Using hydraulic roll force systems, steel makers have the ability to control precisely their steel sheet's gauge (thickness) while it is traveling at more than 50 miles per hour through the cold mill. Using feedback or feed-forward systems, a computer's gap sensor adjusts the distance between the reduction rolls of the mill 50-60 times per second. These adjustments prevent the processing of any off-gauge steel sheet. The principal components of a computerised AGC are :

1. Mathematical models that adequately describe the process.

2. Instrumentation to measure the required variables of the system.

3. Control equipment, including a digital computer, to perform the required functions for control of the system.

A process of aging at atmospheric temperature that increases hardness and strength and ordinarily decreases ductility gradually. Age hardening usually follows rapid cooling or cold working. Takes effect on all cold rolled sheets in storage except fully aluminum killed.

A process of aging at atmospheric temperature that increases hardness and strength and ordinarily decreases ductility gradually. Age hardening usually follows rapid cooling or cold working. Takes effect on all cold rolled sheets in storage except fully aluminum killed.

A change in the properties of certain metal and alloys (such as steel) that occurs gradually with time at atmospheric temperatures (natural aging) or more rapidly at moderately elevated temperatures (artificial or accelerated aging) after a hot working heat treatment or cold working operation. Artificial aging refers to : quench aging (aging following quenching) and strain aging (aging induced by cold-working). Typical properties impacted are: hardness, yield strength, tensile strength, ductility, impact value, formability, magnetic properties, etc. See also Non-aging and artificial aging.

The principle functions of the alloying elements in tool steels are to increase hardenability ; to form hard, wear-resistant alloy carbides; and to increase resistance to softening on tempering. The alloy tool steels may be roughly classified according to the extent of their utilization of these three functions :

1. Relatively Low-alloy Tools Steels : These are of higher hardenability that the plain carbon tool steels in order that they may be hardened in heavier sections or with less drastic quenches and thereby less distortion.

2. Intermediate Alloy Tool Steels : These steels usually contain elements such as tungsten, molybdenum or vanadium, which form hard, were-resistant carbides.

3. High-speed Tool Steels : These contain large amounts of the carbide-forming elements which serve not only to furnish wear-resisting carbides but also to promote secondary hardening and thereby to increase resistance to softening at elevated temperature.

What A heat or thermal treatment process by which a previously cold-rolled steel coil is made more suitable for forming and bending. The steel sheet is heated to a designated temperature for a sufficient amount of time and then cooled. 

Why The bonds between the grains of the metal are stretched when a coil is cold rolled, leaving the steel brittle and breakable. Annealing re-crystallizes the grain structure of steel by allowing for new bonds to be formed at the high temperature. Annealing may be done to induce softness, improving machinability, improving cold-working properties, obtaining a desired structure, reducing stresses and to facilitate diffusion process.

How There are two ways to anneal cold-rolled steel coils : batch and continuous. 

(1) Batch (Box). Three to four coils are stacked on top of each other, and a cover is placed on top. For up to three days, the steel is heated in a non-oxygen atmosphere (so it will not rust) and slowly cooled. 

(2) Continuous. Normally part of a coating line, the steel is uncoiled and run through a series of vertical loops within a heater: The temperature and cooling rates are controlled to obtain the desired mechanical properties for the steel. 

The various annealing processes are : full annealing, sub-critical (or process) annealing, isothermal annealing and spheroidization annealing.

A final partial anneal that softens a cold worked non-ferrous alloy to a specified level of hardness or tensile strength.

A final partial anneal that softens a cold worked non-ferrous alloy to a specified level of hardness or tensile strength.

Tin bars that are put in the plater cells and are important to the plating process in the Tin Mill.

Air Preheater

Heat Exchanger that preheats the Combustion Air used in the Burners of the Reducing Gas Heater by recovering waste heat from the Flue Gas.

Backwash - A process for thoroughly cleaning the filter medium and/or dissolving and flushing away build-up (fouling) on the Heat Exchanger channel plates by reversing the flow of water through the filter and/or channel plates.

Battery Limits - Geographical boundaries of the Technology Supplier scope, as set forth in the project scope matrix.

Blower Area Sump - A sump which collects water and condensate generated in the process. 

Bottom Seal Gas - The Seal Gas or Nitrogen injected at the Reduction Furnace or Product Cooler Bottom Seal Leg to maintain system pressure.

Bottom Seal Gas Bubbler - Water seal through which the Bottom Seal Gas System for the HDRI Discharge System may vent in the event of over pressure..

Bottom Seal Gas Bubbler - Water seal through which the Bottom Seal Gas System for the HDRI Discharge System may vent in the event of over pressure..

Charge Hopper - A material storage bin located on top of the Reduction Furnace that receives the iron oxide feed and supplies it to the Reduction Furnace.

Cold Discharge Plant - Plant designed to discharge DRI at ambient pressure and near ambient temperature.

Cold Preop - The period of initial system checkout and cold run tests (with and without load) under simulated operating conditions.

Combustion Fuel - Top gas fuel, Syngas and Propane that is burned in the Burners of the Reducing Gas Heater.

Cooling Gas - The gas circulated within the Reduction Furnace Cooling Zone or Product Cooler used to cool the Metallized Product.

Cooling Gas Aftercooler- Direct contact cooler on the discharge of the Cooling Gas Compressor to remove the heat of compression.

A charge is a set of at least one coke and one ferrous material batch. Within a charging cycle each charge has a different

composition (otherwise the batch itself would constitute a charging cycle)

A centrifugal compressor or Rotary blower used to circulate Cooling Gas evenly through the Metallized Product in the Cooling Zone of the Reduction Furnace or in the Product Cooler.

- The process in which Oxygen is removed from iron oxide by

reacting with Reducing Gas to form iron according to the following steps:

Fe2O3  ?  Fe3O4  ?  FeO  ?  Fe

(Hematite ? Magnetite ? Wustite ? Iron)

Dirty Process Water - Water that comes into direct contact with particulate-laden gases from the Top Gas Scrubber, Cooling Gas Scrubber, and various coolers and dust collection scrubbers. DISCHARGE DELAY - An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a limited time (about 10 to 15 minutes) but the flow of Reducing gas continues and no changes are made to process control parameters.

DISCHARGE DELAY must end when the Top Gas temperature becomes too high. DRI - See Direct Reduced Iron. Dryer - A device used to remove moisture from a gas stream. Dual Discharge Plant - MIDREX Plant designed and equipped to produce hot (HBI or HDRI)

and cold (DRI) Metallized Product. Dust Collection System - A system consisting of hoods, pipes, cyclones, scrubbers, and fans

used to collect and remove dust generated by oxide and Metallized Product handling,discharge, and storage systems.  Most Plants have multiple Dust Collection Systems. Electrical Interlock System - See Interlocks. EXTENDED DISCHARGE DELAY - An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a period of time greater than 15 minutes 

A long-term maintenance condition when the Seal Gas Compressors are stopped, the Process Gas and Cooling Gas Compressors are shut down, and the Reducing Gas Heater box temperature is maintained at 1000° C.  The Reduction Furnace or ProductCooler may contain some Metallized Product. Feeder - Vibrating, screw, rotary wheel, or belt conveyor-type equipment that controls the discharge rate of bulk material from the bottom of bins and hoppers.  Plants use vibrating Feeders to control the discharge rate of Metallized Product from the Reduction Furnace or Product Cooler. Feed Gas - The controlled composition mixture of Lean Process Gas and Syngas fed to the

Reducing Gas Heater. Feed Gas Mixer - The device in which Lean Process Gas and Process Syngas are mixed to form Feed Gas. Feed Gas Preheater - A heat exchanger that uses waste heat from the Flue Gas in the convection section to preheat the Feed Gas prior to entering the radiant section of the Reducing Gas Heater. Feed Gas Saturator - Direct contact cooler with a mixture of hot and cold water to control the water content in the Feed Gas to the Reducing Gas Heater. Feed Legs - An arrangement of pipes used to distribute the Oxide Feed uniformly within the Reduction Furnace.

A controlled mixture of Oxide Pellets, Lump Ore, and other iron-bearing materials that make up the feed for the Reduction Furnace.Fines - Undersized oxide or metallized materials resulting from handling and screening Oxide Feed and Metallized Product.  A limited percentage of Fines can be added to the Reduction Furnace Feed Mix. Fines Conveyor - A belt conveyor at the discharge of the oxide, Product, or Remet screens used to transport Fines to the appropriate storage bunker. Flue Gas - Product of combustion from the Burners in the Reducing Gas Heater, which prior to being released to the atmosphere through the Stack is used to preheat various gas streams.  A

small amount of Flue Gas is cooled and compressed and used as Seal Gas throughout the MIDREX Process.Flue Gas Blower- Induced draft fan that evacuates flue gases from the Reducing Gas Heater to the atmosphere. Fuel Gas - A name for Top Gas Fuel, Syngas or Propane used as fuel in the Burners of the Reducing Gas Heater. Furnace Discharge - Lower part of the Reduction Furnace where Metallized Product enters the PDC, (Product Discharge Chamber) Product Cooler, or the Furnace Discharge Feeder

depending on the type of Plant. Furnace Discharge Feeder - A vibrating feeder used to discharge DRI from the bottom of the Reduction Furnace of a Cold Discharge Plant.

 Device installed at the discharge of a hot discharge furnace that simultaneously distributes hot Metallized Product to a Product Cooler and a PDC. (Product Discharge Chamber) Gas Sample Cooler - An air or water-cooled device permanently attached in a hot gas stream to cool a representative gas sample for analysis and control. Gas Sample Probe - A device normally attached permanently in a cold gas stream to extract a representative gas sample for analysis.

HBI - Hot Briquetted Iron (HBI).

HDRI - Hot DRI.

HDRI Discharge System - Equipment located between Reduction Furnace lower cone and either a hot briquetting system, hot rotary feeder, or hot transport vessels.  System consists of slide gates, seal leg, PDC,(Product Discharge Chamber) surge hopper, HPD, (Hot Product Distributor) feed leg(s), and shut off valves. Heat Exchanger  A device that transfers heat from one fluid to another without allowing them to mix. Heat Recovery System - A system of coils mounted in the convection section of the Reducing Gas Heater that recovers heat from the Flue Gas drawn from the radiant section  The heat is used to preheat various process streams prior to use.  The spent Flue Gas is exhausted into the atmosphere through the Stack. The streams pre-heated are Feed Gas, Syngas and Combustion Air.

The mineralogical name for Fe2O3 (69.94% iron and 30.06% Oxygen).  Hematite is a naturally occurring mineral.  It can have a color ranging from steel gray through a dull or bright red, with consistency ranging from earthy to crystalline. HOT - Condition when the Reduction Furnace Burden is above 700° C.  A “hot” Reducing Gas Heater condition exists when all of the thermocouples inside the Heater read above 815° C (i.e., minimum temperature for lighting Burners). Hot Discharge Plant - A MIDREX Plant equipped with a Hot Discharge Reduction Furnace. The hot DRI can be discharged directly to an electric arc furnace (EAF) or into a Hot Transport

System, briquetted into HBI, or cooled in a Product Cooler. Hot Discharge Reduction Furnace - A vertical shaft furnace in which oxide is charged, heated, reduced, and discharged at elevated temperatures (650-750° C) as hot Metallized Product. HOTLINK® - A system designed by Midrex Technologies, Inc. (Midrex) to discharge and transport HDRI to an electric arc furnace (EAF) or similar melter using gravity flow. Hot Preop - The period starting with 24-hour operation of the various plant systems, extending through lighting the auxiliary burners, and ending with the completion of refractory dry out. Hot Product Distributor (HPD) - Device installed below the PDC (Product Discharge Chamber) that distributes hot DRI to the Hot Transport System. Hot Transport System - Combination of specially designed equipment used to move hot DRI from the Reduction Furnace to the steel mill for charging into an EAF.  System can be based

on a hot transport conveyor or insulated transport vessels. Hot Well - A sump for hot water collection and distribution.

Reductant component (with Carbon Monoxide) in the MIDREX Process Reductant- to-Oxidant Ratio.  See Carbon Monoxide and Reductant-to-Oxidant Ratio. IDLE - An operating condition when all systems are on “standby,” ready to start production. The Reducing Gas Heater box temperature is maintained at 1000° C by the Burners, and the Seal Gas Compressor on full recycle only.  However, no flow is circulated through the Reducing Gas System.  The furnace contains some Metallized Product, and the Process Gas and Cooling Gas Compressors are running on recycle. Impulse Purge Gas - Nitrogen or other Inert Gas that is stored in a tank and supplied in

metered quantities to the process instrumentation impulse system to prevent solids or condensate buildup in the instrument lines.

Inert Gas - Gas (often Nitrogen) containing little or no Oxygen that has limited reaction with Metallized Product and does not support combustion. Inert Gas Generator - Device that generates Inert Gas or wet Seal Gas.  Its operation is independent of the Reducing Gas Heater. Instrument Air - The clean, dry, oil-free compressed air used to operate the pneumatic instruments and diaphragm actuated valves throughout the Plant. Interlocks - A part of the control system designed to achieve sequential operation, protect equipment, and ensure operating safety. Interruption - An unexpected SHUTDOWN or reduction in production caused by instrument or equipment failure, operator error, or lack of adequate support facilities.

Product Discharge Chamber.

PDC Feed Leg Shutoff Valve - A gas-tight ball valve that closes to help isolate the HDRI discharge system from the Reduction Furnace.

Performance Guarantee Test (PGT) - A series of operational tests detailed in the plant supply contract that demonstrates the plant performance.  Also see Process Guarantee.

Plant - See Direct Reduction Plant.

Plant Air - The utility air supply for pneumatically operated equipment and general Plant use.

Port Tiles - The refractory that forms a series of holes around the bottom periphery of the Bustle through which Bustle Gas enters the Reduction Furnace.

Process - See Direct Reduction Process.

Process Control System (PCS) - A redundant, microprocessor-based controller with operator graphics.

Process Gas - The Top Gas that has been cooled and cleaned of solid particulates in the Top Gas Scrubber and subsequently compressed and recycled to the CO2 Removal System.

Process Gas Aftercooler- Direct contact cooler on the discharge of the Process Gas Compressors to remove the heat of compression and to adjust the Process Gas water content to accommodate the CO2 Removal system.

 A centrifugal or Rotary Lobe compressor used to circulate Process Gas through the Reducing Gas Heater and Reduction Furnace.  Two-stage operation is needed to achieve the required circulation pressure.

Process Guarantee - Guarantee of specific process production parameters during a defined test period.

Process Gas Mist Eliminator - Vertical, cylindrical vessel located upstream of the Process Gas Compressors containing a mist eliminator/demisting pad that removes any liquid water from the Process Gas prior to gas entering the compressors.

Process Syngas - The Syngas that is mixed with Process Gas to yield a Feed Gas composition satisfactory for the Reduction Process..

Process Water - Water used to clean and cool the various gas streams and equipment.  After treatment in the Clarifier, the Process Water is cooled in the Cooling Tower or Seawater Heat Exchangers and recirculated through the Process.

Process Water Sump - A sump for distribution of Process Water to various users of hot and cold Process Water.

Product - See Metallized Product.

Product Cooler - A conical vessel designed to cool 750° C DRI to less than 60° C before it is discharged onto the product storage conveyor.  It resembles the lower cone of a cold discharge Reduction Furnace but is a completely separate unit with a domed roof.

 A vibrating feeder used to discharge DRI from the bottom of the Product Cooler.

Product Cooler Feed Leg - A part of the discharge system of a dual discharge plant that connects the Reduction Furnace to the Product Cooler.

Product Discharge Chamber (PDC) - A chamber lined with refractory and heat-resistant alloy located at the bottom of the Reduction Furnace containing the furnace discharge device,product sizing and surge capacity equipment.

Product Fines Bunker - Storage site for undersized Metallized Product from the Product Screen.

Product Screen - A vibrating screen that removes fines and oversize material from the Metallized Product.

Product Silo - A specially designed bin to safely store Metallized Product.

Proportioning Hopper - See Octopus.

Purge Gas - Nitrogen or other Inert Gas used to maintain a minimum system pressure in the reducing Gas system during a SYSTEM PURGE.

Purge Gas Compressor - A compressor that pressurizes dry Seal Gas or nitrogen for storage in the Purge Gas Tanks.

Purge Gas Tanks - Pressure vessels that store the necessary volume of Inert Gas to purge the entire plant of combustible gases.

 In Cold Discharge Plants, a vertical shaft furnace containing Reduction, Transition, and Cooling Zones in which oxide material is heated, reduced, carburized, cooled to near ambient temperature, and discharged.  In Hot Discharge Plants, a vertical shaft furnace

containing Reduction and Transition Zones in which oxide material is heated, reduced, carburized, and discharged (as HDRI or briquetted as HBI).

Reduction Zone - The upper part of the Reduction Furnace, from the Bustle to the upper level of the Burden, where the Reduction reactions occur.

Refractory Dry-out - The period of Hot Preop when refractory temperatures are precisely increased over time in order to properly cure the refractory for OPERATION.

Remet - Product that does not meet required specifications and is eventually reprocessed (remetallized) in the Reduction Furnace.

Screensizer - An apparatus in the PDC (Product Discharge Chamber) that screens out oversize material and discharges them to the oversize or tramp collection area.

Seal Gas - A controlled, low Oxygen gas taken from the Flue Gas of the Reducing Gas Heater. Seal Gas is cleaned, cooled, and compressed for use in the seals of the Reduction Furnace and as Impulse Purge Gas, Purge Gas, etc.  An Inert Gas Generator also can supply Seal Gas.

Seal Gas Aftercooler - A cooler downstream of the Seal Gas Compressor used to remove the heat of compression.

Seal Gas Compressors - Positive displacement, rotary lobe compressors that provide Seal Gas for various uses in the Plant.

A cooler that lowers a portion of the Flue Gas to a temperature near ambient prior to entering the Seal Gas Compressor.

SHUTDOWN - An operating state characterized by a prolonged stoppage of furnace discharge.  During SHUTDOWN, all Metallized Product is removed from the Reduction Furnace and all combustible gases are purged from the Reducing Gas System.  The resulting

operating condition is COLD.

Slide Gates - Mechanical sealing devices that block material flow and restrict the outward flow of combustible gases from the Reduction Furnace, Product Cooler, and HDRI/HBI seal legs.

Sponge Iron - See Direct Reduced Iron.

Spray Water - Water injected into the rotary lobe compressor inlets to prevent solids buildup, provide cooling, and saturate the transported gas.

Stack - The device used to discharge Flue Gas from the Reducing Gas Heater to the atmosphere

Start-up - The point at which Process Syngas is introduced into the Reducing Gas System.

Stockline - The uppermost level of Oxide Feed in the Reduction Furnace located at the outlet of the Feed Legs.

System Pressure - See Top Gas Pressure.

SYSTEM PURGE - The removal of combustibles from the Reducing Gas System to prepare the Plant for a long-term SHUTDOWN.

Dust-laden gas from the Reduction Furnace that primarily contains Carbon Dioxide (CO2), Water Vapor (H2O), Hydrogen (H2), and Carbon Monoxide (CO).

Top Gas Fuel - The portion of cooled and cleaned Top Gas used as fuel for the Burners of the Reducing Gas Heater.

Top Gas Pressure - The pressure at the inlet of the Process Gas Compressors that ensures air does not infiltrate the Process.  This is the lowest pressure in the Process Gas loop and serves as an interlock to stop the Process Gas Compressor in case a minimum positive pressure is not maintained.  Also called System Pressure.

Top Gas Scrubber - A venturi scrubber that cleans and cools the Top Gas prior to recirculating it in the Process or use as Top Gas Fuel.

Top Seal - A dynamic sealing system that includes the upper seal leg and upper Slide Gate.  It uses Seal Gas to prevent the escape of combustible gases from the Reduction Furnace into the Charge Hopper.

Transition Zone - The part of the Reduction Furnace between the Bustle and the Windboxes (in Cold Discharge Plants) and between the Bustle and the middle Burdenfeeders (in Hot Discharge and Dual Discharge Plants).  The Transition Zone is characterized by a relatively

low flow of gas through the Burden. Transition Zone Syngas - Syngas injected directly into the Transition Zone of the Reduction Furnace to promote product Carburization.

Venturi Booster Pump - A pump that supplies high pressure Process Water to the venturis of the Top Gas and Cooling Gas Scrubbers.

Oxidant component (with Carbon Dioxide) in the MIDREX Process Reductants- to-Oxidants Ratio.  See Carbon Dioxide and Reductants-to-Oxidants Ratio.

Wiper Bar - A volumetric displacement device used to discharge product from the bottom of the Reduction Furnace into the Product Discharge Chamber.

Wustite - The mineralogical name for ferrous oxide (FeO).  In the Reduction Process, iron oxide (as Hematite) is reduced to Magnetite, then to Wustite, and finally to Metallic Iron.  The Reduction reaction FeO ? Fe is the most difficult to accomplish. MIDREX and HOTLINK are registered trademarks of Kobe Steel, Ltd.

 A venturi scrubber that cleans and cools the Cooling Gas before it is recirculated to the Reduction Furnace or Product Cooler.

 Consists of the Cooling Gas Compressor, Cooling Gas Scrubber, Cooling Gas Aftercooler, Cooling Gas Mist Eliminator and Product Cooler. The Cooling Gas System is swept with Purge Gas during SYSTEM PURGE.

 A structure where hot water flows downward vertically and is cooled in an adiabatic process by a countercurrent flow of ambient air.

 A pump that moves Process Water from the hot well of the Process Water Sump to the top of the Cooling Tower.

 A pump that moves Process Water from the hot well of the Process Water Sump to the top of the Cooling Tower.

The lower portion of a cold discharge Reduction Furnace where descending Metallized Product is cooled prior to discharge.

The lower portion of a cold discharge Reduction Furnace where descending Metallized Product is cooled prior to discharge.

The Syngas that is mixed with Cooling Gas prior to entering the Cooling Zone of the Reduction Furnace to promote product carburization and help cool the Bed prior to discharge.

A centrifugal separation device used to remove solid particulates from a gas stream.Day Bin - A storage bin for the Oxide Feed located upstream of the Charge Hopper.

Air supplied by the Combustion Air Blower to control the Flue Gas temperature to the inlet of the Convective section of the Reducing Gas Heater.

A stream of cold Lean Process Gas that is directly recycled to the Bustle Gas without going through the Reducing Gas Heater.  Direct Recycle is used to precisely control Bustle Gas temperature if the Reducing Gas temperature (without Oxygen Injection) or the Bustle Gas temperature (with Oxygen Injection) exceeds the desired Bustle Gas temperature.

 The product of the direct reduction of iron oxide designated by its final form: cold DRI (CDRI), hot DRI (HDRI), or hot briquetted iron (HBI).  Also called Metallized Product or Sponge Iron. Direct Reduction - The solid-state reduction of iron oxide materials to produce a Metallic

Product with a known, consistently uniform iron (Fe) composition for use as feed material in

iron and steel production processes. Direct Reduction Furnace - See Reduction Furnace.

 The product of the direct reduction of iron oxide designated by its final form: cold DRI (CDRI), hot DRI (HDRI), or hot briquetted iron (HBI).  Also called Metallized Product or Sponge Iron. Direct Reduction - The solid-state reduction of iron oxide materials to produce a Metallic

Product with a known, consistently uniform iron (Fe) composition for use as feed material in

iron and steel production processes. Direct Reduction Furnace - See Reduction Furnace.

 The product of the direct reduction of iron oxide designated by its final form: cold DRI (CDRI), hot DRI (HDRI), or hot briquetted iron (HBI).  Also called Metallized Product or Sponge Iron. Direct Reduction - The solid-state reduction of iron oxide materials to produce a Metallic

Product with a known, consistently uniform iron (Fe) composition for use as feed material in

iron and steel production processes. Direct Reduction Furnace - See Reduction Furnace.

- The process in which Oxygen is removed from iron oxide by reacting with Reducing Gas to form iron according to the following steps:

Fe2O3  ?  Fe3O4  ?  FeO  ?  Fe

(Hematite ? Magnetite ? Wustite ? Iron)

- The process in which Oxygen is removed from iron oxide by reacting with Reducing Gas to form iron according to the following steps:

Fe2O3  ?  Fe3O4  ?  FeO  ?  Fe

(Hematite ? Magnetite ? Wustite ? Iron)

water that comes into direct contact with particulate-laden gases from the Top Gas Scrubber, Cooling Gas Scrubber, and various coolers and dust collection scrubbers.

- An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a limited time (about 10 to 15 minutes) but the flow of Reducing gas continues and no changes are made to process control parameters.

DISCHARGE DELAY must end when the Top Gas temperature becomes too high.

- An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a limited time (about 10 to 15 minutes) but the flow of Reducing gas continues and no changes are made to process control parameters.

DISCHARGE DELAY must end when the Top Gas temperature becomes too high.

- An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a limited time (about 10 to 15 minutes) but the flow of Reducing gas continues and no changes are made to process control parameters.

DISCHARGE DELAY must end when the Top Gas temperature becomes too high.

- An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a limited time (about 10 to 15 minutes) but the flow of Reducing gas continues and no changes are made to process control parameters.

DISCHARGE DELAY must end when the Top Gas temperature becomes too high.

 A system consisting of hoods, pipes, cyclones, scrubbers, and fans used to collect and remove dust generated by oxide and Metallized Product handling, discharge, and storage systems.  Most Plants have multiple Dust Collection Systems.

 An operating state when the Reduction Furnace or Product Cooler discharge system is stopped for a period of time greater than 15 minutes but less than an hour.  Process control parameters must be changed, and reducing gas flow may

be stopped.

  A long-term maintenance condition when the Seal Gas Compressors are stopped, the Process Gas and Cooling Gas Compressors are shut down, and the Reducing Gas Heater box temperature is maintained at 1000° C.  The Reduction Furnace or Product

Cooler may contain some Metallized Product.

  A long-term maintenance condition when the Seal Gas Compressors are stopped, the Process Gas and Cooling Gas Compressors are shut down, and the Reducing Gas Heater box temperature is maintained at 1000° C.  The Reduction Furnace or Product

Cooler may contain some Metallized Product.

  Vibrating, screw, rotary wheel, or belt conveyor-type equipment that controls the discharge rate of bulk material from the bottom of bins and hoppers.  Plants use vibrating Feeders to control the discharge rate of Metallized Product from the Reduction Furnace or

Product Cooler.

  The controlled composition mixture of Lean Process Gas and Syngas fed to the Reducing Gas Heater.

  The controlled composition mixture of Lean Process Gas and Syngas fed to the Reducing Gas Heater

  The device in which Lean Process Gas and Process Syngas are mixed to form Feed Gas.

 A heat exchanger that uses waste heat from the Flue Gas in the convection section to preheat the Feed Gas prior to entering the radiant section of the Reducing Gas Heater.

 - Direct contact cooler with a mixture of hot and cold water to control the water content in the Feed Gas to the Reducing Gas Heater.

 - Direct contact cooler with a mixture of hot and cold water to control the water content in the Feed Gas to the Reducing Gas Heater.

 A controlled mixture of Oxide Pellets, Lump Ore, and other iron-bearing materials that make up the feed for the Reduction Furnace.

 A controlled mixture of Oxide Pellets, Lump Ore, and other iron-bearing materials that make up the feed for the Reduction Furnace.

 A controlled mixture of Oxide Pellets, Lump Ore, and other iron-bearing materials that make up the feed for the Reduction Furnace.

 Undersized oxide or metallized materials resulting from handling and screening Oxide Feed and Metallized Product.  A limited percentage of Fines can be added to the Reduction Furnace Feed Mix.

A belt conveyor at the discharge of the oxide, Product, or Remet screens used to transport Fines to the appropriate storage bunker.

Flue Gas - Product of combustion from the Burners in the Reducing Gas Heater, which prior to being released to the atmosphere through the Stack is used to preheat various gas streams.  A small amount of Flue Gas is cooled and compressed and used as Seal Gas throughout the MIDREX Process.

A belt conveyor at the discharge of the oxide, Product, or Remet screens used to transport Fines to the appropriate storage bunker.

Flue Gas - Product of combustion from the Burners in the Reducing Gas Heater, which prior to being released to the atmosphere through the Stack is used to preheat various gas streams.  A small amount of Flue Gas is cooled and compressed and used as Seal Gas throughout the MIDREX Process.

A belt conveyor at the discharge of the oxide, Product, or Remet screens used to transport Fines to the appropriate storage bunker.

Flue Gas - Product of combustion from the Burners in the Reducing Gas Heater, which prior to being released to the atmosphere through the Stack is used to preheat various gas streams.  A small amount of Flue Gas is cooled and compressed and used as Seal Gas throughout the MIDREX Process.

Induced draft fan that evacuates flue gases from the Reducing Gas Heater to the atmosphere.

A belt conveyor at the discharge of the oxide, Product, or Remet screens used to transport Fines to the appropriate storage bunker.

Product of combustion from the Burners in the Reducing Gas Heater, which prior to being released to the atmosphere through the Stack is used to preheat various gas streams.  A small amount of Flue Gas is cooled and compressed and used as Seal Gas throughout the MIDREX Process.

Device installed at the discharge of a hot discharge furnace that simultaneously distributes hot Metallized Product to a Product Cooler and a PDC.

Device installed at the discharge of a hot discharge furnace that simultaneously distributes hot Metallized Product to a Product Cooler and a PDC.

An air or water-cooled device permanently attached in a hot gas stream to cool a representative gas sample for analysis and control

A device normally attached permanently in a cold gas stream to extract a representative gas sample for analysis.

A system of coils mounted in the convection section of the Reducing Gas Heater that recovers heat from the Flue Gas drawn from the radiant section  The heat is used to preheat various process streams prior to use.  The spent Flue Gas is exhausted into the atmosphere through the Stack. The streams pre-heated are Feed Gas, Syngas and Combustion Air.

The mineralogical name for Fe2O3 (69.94% iron and 30.06% Oxygen).  Hematite is a naturally occurring mineral.  It can have a color ranging from steel gray through a dull or bright red, with consistency ranging from earthy to crystalline.

Condition when the Reduction Furnace Burden is above 700° C.  A “hot” Reducing Gas Heater condition exists when all of the thermocouples inside the Heater read above 815° C (i.e., minimum temperature for lighting Burners).

A vertical shaft furnace in which oxide is charged, heated, reduced, and discharged at elevated temperatures (650-750° C) as hot Metallized Product.

A system designed by Midrex Technologies, Inc. (Midrex) to discharge and transport HDRI to an electric arc furnace (EAF) or similar melter using gravity flow.

The period starting with 24-hour operation of the various plant systems, extending through lighting the auxiliary burners, and ending with the completion of refractory dry out

Device installed below the PDC (Product Discharge Chamber) that distributes hot DRI to the Hot Transport System.

Reductant component (with Carbon Monoxide) in the MIDREX Process Reductant- to-Oxidant Ratio.  See Carbon Monoxide and Reductant-to-Oxidant Ratio.

An operating condition when all systems are on “standby,” ready to start production.The Reducing Gas Heater box temperature is maintained at 1000° C by the Burners, and the seal Gas Compressor on full recycle only.  However, no flow is circulated through the reducing Gas System.  The furnace contains some Metallized Product, and the Process Gas and Cooling Gas Compressors are running on recycle.

Nitrogen or other Inert Gas that is stored in a tank and supplied in metered quantities to the process instrumentation impulse system to prevent solids or condensate buildup in the instrument lines.

Gas (often Nitrogen) containing little or no Oxygen that has limited reaction with metallized Product and does not support combustion.

The clean, dry, oil-free compressed air used to operate the pneumatic instruments and diaphragm actuated valves throughout the Plant.

An unexpected SHUTDOWN or reduction in production caused by instrument or equipment failure, operator error, or lack of adequate support facilities.

The equipment that mixes dry lime with water and adds it to the clarifier to raise the pH of the water and to increase Clarifier efficiency.

Unprocessed, screened Hematite ore used (up to 30.0%) with Oxide Pellets in the Oxide Feed mix.

An indirect Heat Exchanger that cools the closed loop Machinery Cooling Water with a stream of cooled Process Water.

The mineralogical name for Fe3O4 (72.36% iron and 27.64% Oxygen).  Magnetite is a naturally occurring mineral, ranging in color from steel gray to black, with a crystalline consistency.

A central panel located in the Plant control room used to monitor, control, and record most Process functions.

A quantitative term used to express the degree of Reduction defined as: kg metallic iron / kg total iron x 100%.

The iron oxide material that has been processed by Direct Reduction to form MIDREX® Iron (in DRI, HDRI, or HBI forms).

See Metallized Product.

A centrifugal or impingement-type separation device that removes water droplets from saturated gases.

Supplies N2 gas for use as Impulse Purge Gas and Purge Gas in some plant designs.  Used as backup to Purge Gas system in some plant designs.  Can be used to provide dry Seal Gas when normal supply from the Seal Gas system is not available or insufficient.

Another name for the assembly consisting of the Proportioning Hopper and the oxide feed distribution legs at the top of the reduction furnace.

The operating state when Metallized Product is discharged from the Reduction Furnace or Product Cooler and Feed Gas is heated in the Reducing Gas Heater and circulated through the Reducing Gas System.

Water Vapor (H2O) and Carbon Dioxide (CO2), minor constituents of Reducing Gas(<5%).

A system consisting of all the equipment required to unload, load,move, store, segregate, mix, and prepare Oxide Feed for processing in the Reduction Furnace.

Spherically shaped, 5-15 mm (nominal) diameter, indurated pellets consisting of iron oxide and small amounts of gangue and trace elements present in the raw ore during the pelletizing process.

 Oxidant component (with Water Vapor) in the MIDREX Process Reductants-to-Oxidants Ratio.  See Water Vapor and Reductants-to-Oxidants Ratio.

 The closely controlled introduction of Oxygen (O2) into the Reducing Gas system to achieve a higher Bustle Gas temperature than Reducing Gas temperature, which increases Reduction Furnace production.  An Oxide Coating System usually is required when a plant uses Oxygen Injection.

 Product Discharge Chamber

A gas-tight ball valve that closes to help isolate the HDRI discharge system from the Reduction Furnace.

A series of operational tests detailed in the plant supply contract that demonstrates the plant performance.  Also see Process Guarantee.

The refractory that forms a series of holes around the bottom periphery of the Bustle through which Bustle Gas enters the Reduction Furnace.

See Direct Reduction Process.Process Control System (PCS) - A redundant, microprocessor-based controller with operator graphics.

Process Gas - The Top Gas that has been cooled and cleaned of solid particulates in the Top Gas Scrubber and subsequently compressed and recycled to the CO2 Removal System.

Direct contact cooler on the discharge of the Process Gas Compressors to remove the heat of compression and to adjust the Process Gas water content to accommodate the CO2 Removal system.

Guarantee of specific process production parameters during a defined test period.

Vertical, cylindrical vessel located upstream of the Process Gas Compressors containing a mist eliminator/demisting pad that removes any liquid water from the Process Gas prior to gas entering the compressors.

The Syngas that is mixed with Process Gas to yield a Feed Gas composition satisfactory for the Reduction Process.

Water used to clean and cool the various gas streams and equipment.  After treatment in the Clarifier, the Process Water is cooled in the Cooling Tower or Seawater Heat Exchangers and recirculated through the Process.

A sump for distribution of Process Water to various users of hot and cold Process Water.

See Metallized Product.

A conical vessel designed to cool 750° C DRI to less than 60° C before it is discharged onto the product storage conveyor.  It resembles the lower cone of a cold discharge Reduction Furnace but is a completely separate unit with a domed roof.

A vibrating feeder used to discharge DRI from the bottom of the Product Cooler.

A part of the discharge system of a dual discharge plant that connects the Reduction Furnace to the Product Cooler.

A chamber lined with refractory and heat-resistant alloy located at the bottom of the Reduction Furnace containing the furnace discharge device, product sizing and surge capacity equipment.

A vibrating screen that removes fines and oversize material from the metallized Product.

A specially designed bin to safely store metallized product.

Nitrogen or other Inert Gas used to maintain a minimum system pressure in the reducing Gas System during a SYSTEM PURGE.

A compressor that pressurizes dry Seal Gas or nitrogen for storage in the Purge Gas Tanks.

Pressure vessels that store the necessary volume of Inert Gas to purge the entire plant of combustible gases.

Expressed as the reductants-to-oxidants ratio (H2 + CO)/(H2O + CO2) when referring to Reducing Gas or Bustle Gas and as higher Product Metallization when referring to metallized Product.  See Reductants-to-Oxidants Ratio.

A conveyor that transports Briquettes or Bypass Feeder discharge through the Quench Tank for cooling, to the product collection conveyor.

Refractory lined duct from the outlet of the Reducing Gas Heater to the Reducing Gas Mixer.

It consists of the Reduction Furnace, Top Gas Scrubber, Feed Gas preheater, Reducing Gas Heater, and the piping connecting these vessels.  The Reducing Gas System is pressurized with Purge Gas during SYSTEM PURGE.

The Quality of Reducing Gas and Bustle Gas, as expressed in the following equation:

(H2 + CO)/(H2O + CO2).

See Direct Reduction.

See Direct Reduced Iron

See Top Gas Pressure.

A charge is a set of at least one coke and one ferrous material batch. Within a charging cycle each charge has a different

composition (otherwise the batch itself would constitute a charging cycle).

charging cycle is a cyclically sequence of charges. Each charging cycle respects the targeted burden composition.

A section is a continuous part of material discharged from a single weighing hopper. Sections can be queued or overlapped

one with the other.

A series of documents, approved and published by ASTM, that include specifications or requirements, practices, guides, test methods, etc., covering various materials, products, systems or services. In the steel industry, the steel related ASTM standards are used by both the producers and users to ensure that a steel product or service meets all intended requirements. See American Society for Testing and Materials.

 

A valve that is located in the exhaust line of a turbine and is designed to open up and get a positive pressure in the exhaust line.

 

 

 

 

The largest category of stainless steel, generally non-magnetic, accounting for about 70% of all production. Refers to a particular grain structure of steel which in normal steel exists at high temperature. In stainless steel, this structure exists at room temperature and imparts certain characteristic properties. The austenitic class offers the most resistance to corrosion in the stainless group, owing to its substantial nickel content and higher levels of chromium. Austenitic stainless steels are hardened and strengthened through cold working (changing the structure and shape of steel by applying stress at low temperature) instead of by heat treatment. Ductility (ability to change shape without fracture) is exceptional for the austenitic stainless steels. Excellent weldability and superior performance in very low-temperature services are additional features of this class. Applications include cooking utensils, food processing equipment, exterior architecture, equipment for the chemical industry, truck trailers, and kitchen sinks. The two most common grades are type 304 (the most widely specified stainless steel, providing corrosion resistance in numerous standard services) and type 316 (similar to 304 with molybdenum added, to increase opposition to various forms of deterioration).

 

The size attained by the grains in steel when heated to the autenitic region. This may be revealed by appropriate etching of cross sections after cooling to room temperature.

 

Heating after pickling /or pickling and coating to remove hydrogen.

Refers to metal strap signode band that is one half inch wide. This band is used to thread and pull the strip through the line.

Inhomogeneous distribution of alloying elements or phases aligned in filaments or plates parallel to the direction of working.

The part of a forging of major cross section, the length of which usually exceeds the diameter.

A crack in the ingot base caused by restriction to free contraction during solidification.

Unit of area of 112 sheets of Tin Mil products (tin plate, tin free steel or black plate) 14 by 20 inches, or 31,360 square inches. Tin plate is sold, and carried in finished inventory, on a weight per unit area rather than on a thickness basis.

What A pear-shaped furnace, lined with refractory bricks, that refines molten iron from the blast furnace and scrap into steel. Up to 30% of the charge into the BOF can be scrap, with hot metal accounting for the rest. 

Why BOFs, which can refine a heat (batch) of steel in less than 45 minutes, replaced open-hearth furnaces in the 1950s; the latter required five to six hours to process the metal. The BOF's rapid operation, lower cost and ease of control give it a distinct advantage over previous methods. How Scrap is dumped into the furnace vessel, followed by the hot metal from the blast furnace. A lance is lowered from above, through which blows a high-pressure stream of oxygen to cause chemical reactions that separate impurities as fumes or slag. Once refined, the liquid steel and slag are poured into separate containers.

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A steel making process in which steel is refined under a basic slag in a basic refractory lined furnace or convertor.

A refractory material basic in chemical composition and containing high amounts of such oxides as lime and magnesia, for example, calcined dolomite or magnetite.

The band (strapping) that goes around the outside diameter of a coil.

 Various tests used to assess the ductility of steel when subjected to bending. Tests may include determination of the minimum radius or diameter required to make a satisfactory bend and the number of repeated bends that the material can withstand without failure when it is bent through a given angle and over a definite radius. 

 A steel making process in which pig iron is refined in an acid refractory lined convertor by blowing air or a mixture of air, carbon dioxide and oxygen or steam through the molten metal. The basic process is known as Thomas process.

 Rope wire drawn to tensile strength of 128 to 147 kgf/mm2.

 Patented rope wire drawn to a tensile strength of 155 to 170 kgf/mm2.

g. Organic Binders : Organic binders include tars, pitches, or resins for use in reducing atmospheres where the carbon residuals impart bonding strength or act to inhibit alteration.

Liquid pig iron which has been subjected to blowing in the converter, as a result of which the iron is refined to the degree depending on requirement. Blown metal is made into steel by addition of elements as required.

Heating hot rolled ferrous sheet in an open furnace to a temperature within the transformation range then cooling in air to soften the metal. A bluish oxide surface layer is formed.

A thin film of phosphate pretreatment applied to a steel surface (bare or zinc coated) to enhance paintability.

A projection on the surface of a forging.

Injection of oxygen, singularly, with additives (such as pulverized lime) or in addition to hydrocarbon fuels (such as natural gas, pulverized coke or fuel oil), all routed in the same manner to initiate reactions in the bath during oxygen steelmaking.

A layer of metal in the space between the base of the mould and the bottom plate which is attached to the ingot. Similarly, a layer of metal may be formed at the top, in the space between the mould and the refractory lined hot top, the layer of metal formed being called top flash.

A cast iron plate of suitable size, on which the bottom of the mould (which is open at both ends) sits. This plate may be recessed or refractory lined.

The splash of metal solidifying on the bottom portion of a mould, and later engulfed in the rising column of liquid steel, and arises from the impact of the liquid steel on the bottom plate in initial stages of teeming.

The greatest deviation from a straight line along a longitudinal edge in a sheet or strip.

Annealing of a metal or alloy in a sealed container under condition that minimise oxidation. See black annealing also.

An operation which produces various degree bends when fabricating parts from steel.

Uncoiler rolls through which the strip passes; composed of a mandrel and leveling rolls which unwind the strip prior to processing through the Pickler. Breaker rolls assist in breaking up the Hot Mill surface scale. 

An accident caused by the failure of the walls of the hearth of the Blast Furnace, resulting in liquid iron or slag (or both) flowing uncontrolled out of the Blast Furnace and cause considerable damage to the furnace and surrounding auxiliaries. The term is also used in continuous casting when the solidified outer shell breaks-out resulting in liquid steel flowing-out and spreading over the casting machine, jeopardising the entire casting operation.

See Slips.

Wire which has been annealed in a controlled atmosphere to prevent surface oxidation.

Bar or wire with a bright finish obtained by cold drawing, machining, grinding etc.

Material which has been turned, ground, shaped or milled to size and finished with a smooth bright surface.

An iron-zinc alloy layer formed between the steel substrate and the free zinc of galvanized coatings.

See Butyl Stearate.

A compression phenomenon that occurs when, after some critical level of load, a bulge, bend, bow, kink, or other wavy condition is produced in a beam, column, plate, bar, or sheet product form.

A coil made by putting together two or more coils to make one max coil or one shippable coil.

Specific number of sheets which equals 1 unit of production. Number is determined by multiplying sheets/Packages/Bundle. For example, an order calls for 112 sheets/package according to the maximum height allowed for a lift. Therefore, multiplying 15 packages X 112 sheets = 1680 sheets/bundle.

In blast furnace, the ratio of iron-bearing materials per charge to the weight of coke.

A defect on the surface of the ingots, usually on their corners, as a result of flame infringement as they are heated in the soaking pits.

(3) In grinding, sufficient heating of the workpiece to cause discoloration or to change the microstructure by tempering or hardening.

Broken edges occurring during hot-rolling and caused by overheating or burning.

Small or large black spots that generally show up on surface and are generally caused by pickling steel too hot.

The very subtle ridge on the edge of strip steel left by cutting operations such as slitting, trimming, shearing, sawing or blanking. For example, as a steel processor trims the sides of the sheet steel parallel or cuts a sheet of steel into strips, its edges will bend with the direction of the cut (see Edge Rolling). 

Devices used to remove build up on edge of strip after the slitting process.

Edges of sheet or strip ruptured due to excessive cold rolling.

2. Compacting wrought iron turnings, borings and scrap into a bloom or slab by heating to a welding temperature and forging.

Rotating disc-type valve which moves 90o from the closed position to the fully open position. Normally used to stop or control the flow through a line, the butterfly regulates steam on the plant service line.

Joining two edges or ends by placing one against the other and welding them.

The standard pipe used in plumbing. Heated skelp is passed continuously through welding rolls, which form the tube and squeeze the hot edges together to make a solid weld.

A lubricant applied on electrolytic chromium coated steel.

Selling term which refers to product sold in the form of a coil vs. cut plate. "Bi Coil" is also used in production to refer to coils vs. cut plate.

Camber is the deviation of a side edge from a straight edge. Measurement is taken by placing a straight edge on the concave side of a sheet and measuring the distance between the sheet edge and the straight edge in the center of the arc. Camber is caused by one side being elongated more than the other due to improper heating, differential expansion or contraction, improper alignment on the hot beds or faulty setting of the rolls. 2. The hook or dogleg near the ends of a coil.

Can measurements are expressed in inches and sixteenths of inches in a kind of shorthand. The standard 12 ounce beverage can, for example, is described as 211 by 413, which translates to a 2 11/16 inches in diameter by 4 13/16 inched in height. When a two piece can is described as 211/209/413, this means 2 11/16 inches in diameter, necked in at the top to a 2 9/16 inches by a 4 13/16 inches in height. 

A close-joint tube of steel over which a close-joint or seamless or welded tube of another metal is drawn.

The surface hardening processes which involve a change in chemical composition of the surface portion. They include carburizing, in which the carbon content of the surface portions is locally increased; nitriding, in which the nitrogen content of the surface portions is increased; and carbonitriding, in which both the carbon and nitrogen contents are increased.

Tubes used for lining bore holes to prevent caving in of the surrounding strata and the undesired entry of water.

Casing is the structural retainer for the walls of oil and gas wells. Casing is used to prevent contamination of both the surrounding water table and the well itself. Casing lasts the life of a well and is not usually removed when a well is closed

Usually the product of a single furnace charge. Sometimes the furnace contents are tapped into two or more ladles when the product of each ladle may be called a separate cast. In the Bessemer process, a cast is also known as a blow.

Refractory concretes made with calcium aluminate (CA) cements and various refractory aggregates uses in various locations like coke oven battery, tundish covers and in soaking pit construction.

An alloy essentially of iron and carbon containing more than 2 percent carbon (usually between 2.5 and 4 percent). It also contains silicon, manganese, sulphur and phosphorus in varying amounts. The character of cast iron is controlled by the manner in which carbon is present, and the fractured surface of cast iron exhibits characteristic colour, namely white, mottle, or grey, depending on whether carbon is present wholly in combined state (as carbide) or partly in combined state or wholly in the form of graphite.

Pouring or teeming molten metal into moulds. This also refers to metal objects so procured. 

A refractory lined receptacle in which liquid steel is received from the furnace for teeming purpose.

The metallographic structure of a casting evidenced by shape and orientation of grains as well as segregation of impurities.

The term is used for steel castings.

Rapidly occurring or accelerating surface damage, deterioration, or change of shape caused by wear to such a degree that the service life of a part is appreciably shortened or its function is destroyed.

A coil of non-standard weight

A common treatment applied to passivate the surface of electrolytic tin plate against the formation of tin oxides.

Ingot top, characterized by numerous bulges (like a cauliflower) found in semi-killed / rimming steel ingots. This is caused by the bleeding of metals, when it has reached a mushy stage.

A form of stress corrosion cracking most frequently encountered in carbon steels or iron-chromium-nickel alloys that are exposed to concentrated hydroxide solutions at temperatures of 200 to 250oC. Also known as caustic embrittlement.

Erosion of a solid surface through the formation and collapse of cavities in an adjacent liquid. Also known as cavitation erosion.

A condition in the band of steel where the center (in the direction of rolling) is longer than the edges and has a wave or buckle. 

The removal of sharp edges (the term is practically synonymous with 'bevelling' but has a less restricted application. 

When the percentage of fines in the blast furnace burden material increases significantly, too much of the burden will be deposited directly below the rim of the bell and very little will reach the walls. As a result, the ratio of burden to coke will be very low near the walls and, since the permeability there will increase because of the increased percentage of coke, the flow of hot gas along the walls will significantly increase. This is termed as channelling and causes excessive heating of the walls. Channelling is no longer a major problem because of changes in furnace top design, charging sequence, and raw material preparation.

Materials charged in a furnace for producing steel. For example, iron ore, coke and limestone are charged into a Blast Furnace; a Basic Oxygen Furnace is charged with scrap and hot metal. Also, the act of loading material into a vessel.

Cast or fabricated steel or cast iron box used for charging material in steel making furnace. Charging basket is fabricated with a false bottom steel container for charging scrap in electric furnace.

To prevent escape of gases from the coke ovens during charging of coke, a steam-jet aspirator is used to draw gases from the space above the charged coal into the collector main. This practice is called 'charging on the main'.

A coating defect consisting of the washboard appearance of the cured film with variations of color or opacity. "Gear marks" is another synonym when the defect is caused by the gear lash of the coating machine. Chattering occurs when the coating machine permits the uneven application of the coating. 

Checked edges in sheet bars and strips occurring during hot-rolling.

A coating defect consisting of the cracking of the cured film into small segments, with hairline cracks separating the segments. The similar defects of mud cracking or alligatoring are the same as checking, but they are larger. Crazing is a synonymous term. 

A customer-specified rust inhibitor applied to the coated product. 2. A passivating chemical treatment normally applied to the steel surface to control oxide formation and growth. 

A chemical addition made to the plating bath that results in a coating with a bright appearance as opposed to the mechanically brightened surface appearance.

The temperature change in degrees Celcius when one kilogram of addition agent is added to one metric ton of liquid steel and, in FPS units, the temperature change in degrees Fahrenheit caused by the addition of one pound of addition agent to one net ton of liquid steel.

Marks on a rolled surface resulting from cracks in the surface of a roll used for hot rolling. A particular form of roll mark. Surface cracks found on rolls are usually caused by alternate heating and cooling or by overheating of the rolls in service, in which case they are called fire cracks.

What A gas-based process developed by Lurgi Metallurgie in Germany to produce DRI or HBI (see Direct Reduced Iron and Hot Briquetted Iron). How The two-stage method yields fines with a 93% iron content. Iron ore fines pass first through a circulating fluidized-bed reactor, and subsequently through a bubbling fluidized-bed reactor. 

What Method of applying a stainless steel / copper / aluminum coating to carbon steel or lower-alloy steel (i.e., steel with alloying element content below 5%). 

Why To increase corrosion resistance at lower initial cost than exclusive use of stainless steel etc. 

How By (1) welding stainless steel onto carbon steel, (2) pouring melted stainless steel around a solid carbon steel slab in a mould, (3) placing a slab of carbon steel between two plates of stainless steel and bonding them by rolling at high temperature on a plate mill, (4) mounting the steel core in a covered mould and heating it out of contact with air to a temperature slightly above the melting point of copper, which then is cast about it, (5) dipping the solid steel core into a bath of molten copper, (6) depositing the copper on steel core electrolytically, (7) rolling flat steel almost to gauge, cleaning it thoroughly and either placing it between two sheets of aluminum and cold rolling or heating to between 315o and 400oC and rolling.

A fracture, usually of a polycrystalline metal, in which most of the grains have failed by cleavage, resulting in bright reflecting facets. It is one type of crystalline fracture and is associated with low-energy brittle fracture.. 

Removing the fash.

A method of coal preparation :the coal is dried and preheated before charging it into coke ovens. The major advantages are : improvement in strength and hardness of coke, usage of poorer quality coals, increase in oven throughput because of reduction in coking time, reduction in overall fuel requirements, more uniform heating of the batteries, and less thermal shock to the refractory brickwork. 

The process of covering steel with another material (tin, chrome, zinc etc.), primarily for corrosion resistance. They can be classified as anodic, cathodic, inert or inhibitive.

1. In the Sheet Mill, the amount of Zinc on a galvanized sheet measured in ounces per square foot. 2. Specified in pounds (or parts thereof) of tin coating per base box. This term is often misunderstood because in most cases the decimal point is omitted when written or printed.

A test of the weight of the coating measured 2 inches from each side of the strip and at the center. 

Steel sheet that has been wound. A slab, once rolled in a hot-strip mill, is more than one-quarter mile long; coils are the most efficient way to store and transport sheet steel. 

A long length of hot rolled bar produced in a continuous rolling mill and coiled in a manner similar to wire rod.

What The basic fuel consumed in blast furnaces in the smelting of iron. It is a hard porous substance that is principally pure carbon. Coke is a processed form of coal, made in oven by driving off volatile elements. In blast furnaces, coke helps generate the 3000o F temperatures and reducing gases needs to smelt iron ore. About 1,000 pounds of coke are needed to process a ton of pig iron, an amount which represents more than 50% of an integrated steel mill's total energy use. 

Why Metallurgical coal burns sporadically and reduces into a sticky mass. Processed coke, however, burns steadily inside and out, and is not crushed by the weight of the iron ore in the blast furnace. 

How Inside the narrow confines of the coke oven, coal is heated without oxygen for 18 hours to drive off gases and impurities. 

Types There are three principal kinds of coke, classified according to the methods by which they are manufactured : Low, medium and high-temperature coke, Coke used for metallurgical purposes must be carbonized in the higher ranges of temperature (between 900o and 1095o) if the product is to have satisfactory physical properties. Even with good coking coal, the product obtained by low-temperature carbonization between 450o and 760o is unacceptable for good blast furnace operation.

What Finishing mills roll cold coils of pickled hot-rolled sheet to make the steel thinner, smoother, and stronger, by applying pressure, rather than heat. How Stands of rolls in a cold-reduction mill are set very close together and press a sheet of steel from one-quarter inch thick into less than an eighth of an inch, while more than doubling its length. 

Coils that are cold worked or reduced to gauge on the tandem mill. 

A product manufactured from hot rolled descaled (pickled) coils by cold reducing to the desired thickness, generally followed by annealing and temper rolling. Strip has a final product width of approximately 12 inches, while sheet may be more than 80 inches wide. Cold-rolled sheet is considerably thinner and stronger than hot-rolled sheet, so it will sell for a premium (see Sheet Steel). If the sheet is not annealed after cold reduction it is known as full hard. (See Full Hard Cold Rolled).

Rolling steel (generally sheet or strip) below its recrystallization temperature with the degree of reduction being usually above 5%. 

What Substantial mechanical working (usually above 5%), for example, drawing, rolling, forging, etc. of a metal or alloy below its normal recrystallization temperature. Why To create a permanent increase in the hardness and strength of the steel. 

How The application of forces to the steel causes changes in the composition that enhance certain properties. In order for these improvements to be sustained, the temperature must be below a certain range, because the structural changes are eliminated by higher temperatures. 

That part of the total carbon in steel or cast iron present as other than free carbon.

Squaring of the strips by use of mechanical shear.

Minimum rate of continuous cooling for preventing undesirable transformations. For steel, unless specified, it is the slowest rate at which austenite can be cooled from above critical temperature to prevent its transformation above the martensite start temperature.

Time-dependent strain, occurring under stress. The creep strain occurring at a diminishing rate is called primary or transient creep; that occurring at a minimum and almost constant rate, secondary or steady-rate creep; that occurring at an accelerating rate, tertiary creep. It is more marked at elevated temperatures and is, therefore, important in connection with metal and alloys for service at high temperature.

Markings on ingot or ingot mould surface in the form of a network, in a mosaic pattern giving the appearance of crocodile skin. 

Tubes of suitable dimensions for the production of couplings. 

Wear in which chemical or electrochemical reaction with the environment is significant.

The intrinsic ability of a material to resist degradation by corrosion. This ability can be enhanced by application of special coatings on the surface of the material or by imparting certain structural changes in the material by addition of alloying elements. 

Cracking produced by the combined action of repeated or fluctuating stress and a corrosive environment at lower stress levels or fewer cycles than would be required in the absence of a corrosive environment.

The gradual degradation or alteration of steel caused by chemical or electrochemical attack due to atmosphere, moisture, or other agents. 

What COREX is a smelting reduction process in which coal is directly used in a melter gasifier as an energy carrier and reducing agent thereby eliminating the need for a blast furnace, sinter plant and coke ovens. It yields hot metal or pig iron that can be used by integrated mills or EAF mills. How The process gasifies non-coking coal in a smelting reactor, which also produces liquid iron. The gasified coal is fed into a shaft furnace, where it removes oxygen from iron ore lumps, pellets or sinter; the reduced iron is then fed to the smelting reactor. 

What A method of pouring steel directly from the furnace into a semi-finished product such as billet, bloom, or slab directly from its molten form. It bypasses the traditional process of pouring (teeming) molten steel into ingots, reheating those ingots, and then rolling them into semi-finished steel shapes. Why Continuous casting avoids the need for large, expensive mills for rolling ingots into slabs. Continuous cast slabs also solidify in a few minutes versus several hours for an ingot. Because of this, the chemical composition and mechanical properties are more uniform. This process has steadily displaced ingot casting due to its advantages of higher yield and improved productivity.How Steel from the BOF or electric furnace is poured into a tundish (a shallow vessel that looks like a bathtub) atop the continuous caster. As steel carefully flows from the tundish down into the water-cooled copper mould of the caster, it solidifies into a ribbon of red-hot steel. At the bottom of the caster, torches cut the continuously flowing steel to form slabs or blooms. 

Tubes used in the conversion of a vapour into a liquid by cooling. 

Material of normally good quality for which limits of chemical composition and mechanical properties are more relaxed.

That part of the total carbon in steel or cast iron present as other than free carbon.

Also called top and bottom blowing or mixed blowing, this process is characterized by both a top blowing lance and a method of achieving stirring from the bottom. The configurational differences in mixed blowing lie principally in the bottom tuyeres or elements. These range from fully cooled tuyeres, to uncooled tuyeres, to permeable elements.

A coarse structure of parallel elongated grains formed by unidirectional growth that is most often observed in castings. This results from diffusional growth accompanied by a solid state transformation.

What Substantial mechanical working (usually above 5%), for example, drawing, rolling, forging, etc. of a metal or alloy below its normal recrystallization temperature. Why To create a permanent increase in the hardness and strength of the steel. How The application of forces to the steel causes changes in the composition that enhance certain properties. In order for these improvements to be sustained, the temperature must be below a certain range, because the structural changes are eliminated by higher temperatures. 

Reducing the cross-sectional area and diameter of a tube by drawing when cold through a die.

An ingot or casting defect resulting from interrupted flow of metal during pouring, causing a discontinuity in the skin.

What Finishing mills roll cold coils of pickled hot-rolled sheet to make the steel thinner, smoother, and stronger, by applying pressure, rather than heat. How Stands of rolls in a cold-reduction mill are set very close together and press a sheet of steel from one-quarter inch thick into less than an eighth of an inch, while more than doubling its length. 

A curvature of the strip in the lengthwise sense, parallel to the direction in which the strip was rolled or uncoiled. 

Loss of carbon from the surface layer of a carbon-containing alloy usually during heating, hot working or heat treatment due to reaction with one or more chemical substances in a medium that contacts the surface. 

The fabrication process of flat rolled steel to make drawn parts. The part is mechanically formed through or in a die. The blank diameter is reduced; the blank contracts circumferentially as it is drawn radially inward. (See Deep Drawing Applications). 

Macroetching specially for steel to determine the overall character of the material that is the presence of imperfections such as seams, forgings, bursts, shrinkage-void remnants, cracks and coring.

A high quality low carbon steel possessing high ductility, desirable grain size, etc. which permits deep drawing. 

1. Anything that renders the steel unfit for the specific use for which it was ordered. What is defective for one customer may be prime steel for another. 2. A variety of quality problems in a coil. Examples are punch marks, roll marks, oil spots, and scratches.

Concrete reinforcing bars in which the surface is provided with lugs or protrusions )called deformations) which inhibit longitudinal movement of the bars relative to the surrounding concrete. The surface deformations are hot formed in the final roll pass by passing the bars between rolls having patterns cut into them so that the surfaces of the bars are forced into the depressions in the rolls to form characteristic deformations. 

What Operation that injects a chemical mixture into a ladle full of hot metal to remove sulfur prior to its charging into the Basic Oxygen Furnace. Why Sulfur enters the steel from the coke in the blast furnace smelting operation, and there is little the steel maker can do to reduce its presence. Because excess sulfur in the steel impedes its welding and forming characteristics, the mill must add this step to the steel making process. 

What Operation that injects a chemical mixture into a ladle full of hot metal to remove sulfur prior to its charging into the Basic Oxygen Furnace. Why Sulfur enters the steel from the coke in the blast furnace smelting operation, and there is little the steel maker can do to reduce its presence. Because excess sulfur in the steel impedes its welding and forming characteristics, the mill must add this step to the steel making process. 

Longitudinal lines on the outer surface of a drawn tube caused by localized seizure between the tube and the die. 

Coatings on flat rolled products whereby the thickness of the coating on the one side is heavier than the other side.

A range by which a product's width and gauge can deviate from those ordered and still meet the order's requirements. (Also See Commercial Tolerance) 

The jet impact zone caused by the impingement of oxygen during lancing operation in steel-making. The oxidation reactions occur in this zone.

Kinks on sheet surface. 

Direct pouring of ingots or castings from ladle, that is, without using any refractory reservoir or tundish, in between.

What A processed iron ore that is iron-rich enough to be used as a scrap substitute in electric furnace steel making. 

Why As mini-mills expand their product abilities to sheet steel, they require much higher grades of scrap to approach integrated mill quality. Enabling the mini-mills to use iron ore without the blast furnace, DRI can serve as a low residual raw material and alleviate the mini-mills' dependence on cleaner, higher-priced scrap. How The impurities in the crushed iron ore are driven off through the use of massive amounts of natural gas. While the result is 97% pure iron (compared with blast furnace hot metal, which, because it is saturated with carbon, is only 93% iron), DRI is only economically feasible in regions where natural gas is attractively priced. 

The processes that produce iron by reduction of iron ore below the melting point of the iron produced. 

Folding a sheet or sheet-pack on itself, about the middle, before rolling further. 

Fracture characterized by tearing of metal accompanied by appreciable gross plastic deformation and expenditure of considerable energy. 

A qualitative, subjective property of material that indicates the extent to which it can be deformed without fracture in metal working operations such as rolling, extrusion, fabrication, etc. fracture at room temperature. It is generally expressed as total permanent strain prior to fracture, measured as elongation or reduction of area during tensile testing.

Dumping occurs when imported merchandise is sold in, or for export to, the domestic market at less than the normal value of the merchandise, i.e., a price which is less than the price at which identical or similar merchandise is sold in the comparison market, the home market (market of exporting country) or third-country market (market used as proxy for home market in cases where home market cannot be used). The normal value of the merchandise cannot be below the cost of production. 

A category of stainless steel with high amounts of chromium and moderate nickel content. The duplex class is so named because it is a mixture of austenitic (chromium-nickel stainless class) and ferritic (plain chromium stainless category) structures. This combination was originated to offer more strength than either of those stainless steels. Duplex stainless steels provide high resistance to stress corrosion cracking (formation of cracks caused by a combination of corrosion and stress) and are suitable for heat exchangers, desalination plants, and marine applications. 

Steel making by a combination of two processes, such as Bessemer and open hearth processes or open hearth and electric processes, the popular combination being one using acid Bessemer convertor and basic open hearth furnace. 

The wavy projections formed in deep-drawing which normally occur in geometric positions either at 45% or at 0% and 90% to the direction of rolling. These are caused by directional properties in the sheet. 

A convenience feature can end designed to be opened by utilizing an integral tab opener to tear the container lid along a tear line formed in the lid. The end is designed so that after the container is opened, safe edges remain on the removable panel portion torn off from the lid body and on the rim remaining on the container. This is accomplished by shielding the residual tear line metal with multi-layer metal folds.

Lack of coincidence of the centre of the bore of a tube with that of the outside circumference, resulting in variation in wall thickness. 

Used to measure physical and mechanical parameters and for the detection of surface imperfections in steel products. Eddy currents are so named because their paths often resemble the circular eddies in water. The eddy current method measures the electromagnetic interaction between a transducer or test coil and the part being inspected. By this interaction such physical parameters as the hardness, steel grade, and case depth can be inferred. In addition, cladding thickness, foil thickness, and the presence of surface or subsurface imperfections may be indicated. 

1. Light-gauge, low-carbon, cold reduced steel on which tin has been electro-deposited. 2. Black plate coated with Tin (Sn) electron deposition. 

A batch process used to produce a zinc coating on manufactured articles. These may be functional (for corrosion protection) or decorative coatings. Electric current is used to force the deposition of negatively charged zinc ions from an acid solution onto the positively charged cathode, which is the article to be coated. Produces thin coatings generally less than 10 um (0.4 mils) thick. 

A continuous process used to produce a zinc coating on steel sheet by electroplating. Both sulfuric or hydrochloric acid solutions are used. The most common method uses sulfuric acid with insoluble anodes. Produces thin coatings generally less than 10 um (0.4 mils) thick. 

A process by which the thickness of alloy deposited on a strip can be determined. 

Car-bottom furnaces where the car is rolled under the furnace shell and then raised into the furnace by a motor-driven lifting mechanism. 

1. Total plastic strain before fracture, measured as a percent or axial strain during tensile testing. 2. This term is also used on orders specifying tensile test on which a minimum elongation between give points and distances has to be met. This elongation is expressed as percent of stretch over a given length, i. e. 25% elongation in 2 inches. 

A coating defect consisting of the crawling or dewetting condition where the wet film recedes and forms a raised (in relief) impression. 

See Electrolytic Tin Coated Sheets. 

A coating defect, similar to cratering, but with exposed metal in the void. 

A producer of intermediate products that does not also produce primary metal. For example, a rebar (see Reinforcing Bar) fabricator purchases rebar and processes the material to the specifications of a particular construction project. 

Curtailing the operation of blast furnace by reducing the quantity of wind being blown (to less than 20-25% of normal). This is done when the full productive capacity of the furnace is not required for a period of time. This technique is used for emergency situations or short periods only (for a few hours at a stretch).

Sharp and ragged edges left after shearing or sawing. 

A process to directly reduce iron ore to metallic iron pellets that can be fed into an electric arc furnace with an equal amount of scrap. This process is designed to bypass the coke oven-blast furnace route to produce hot metal from iron ore. It is also one of several methods that mini-mills might use to reduce their dependence on high-quality scrap inputs (see Direct Reduced Iron and Hot Briquetted Iron). 

The phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the ultimate tensile strength of the material. Fatigue failure generally occurs at loads which applied statically produce little perceptible effect. Fatigue fractures are progressive, beginning as minute cracks that grow under the action of the fluctuating stess. 

Failure that occurs when a specimen undergoing fatigue completely fractures into two parts or has softened or been otherwise significantly reduced in stiffness by thermal heating or cracking. 

A refractory lined receptacle, placed on the mould top or built into the ingot mould to reduce the shrinkage cavity (pipe) by keeping the metal in liquid state longer at the top. This arrangement confines the shrinkage cavity to the feeder head. 

A pipe through which water is forced into a boiler. 

Any raw material. 

A solid solution of one or more elements in body centred cubic iron. In plane carbon steels, the interstitial solid solutions of carbon in a - iron 

The process of producing a predominantly ferritic matrix in a ferrous alloy through an appropriate heat treatment. 

A metal product commonly used as a raw material feed in steel making, usually containing iron and other metals, to aid various stages of the steel making process such as deoxidation, desulfurization, adding strength or for introducing such elements in steel. Examples: ferrochrome, ferromanganese, and ferrosilicon, silicon manganese etc. 

An alloy of iron and chromium with up to 72% chromium. Ferrochrome is commonly used as a raw material in the making of stainless steel.

A gray and amorphous fracture that results when a metal is sufficiently ductile for the crystals to elongate before fracture occurs. When a fibrous fracture is obtained in an impact test, it may be regarded as definite evidence of toughness of the metal. 

Crack in the ingot associated with the formation of fin and the resulting obstruction during contraction while cooling. 

The temperature at which hot mechanical working of metal is completed. 

A refractory material, essentially hydrated aluminium silicate in composition, having a high fusion point used in the manufacture of refractory bricks or mortar. 

An irregular pattern of lines on the surface of a sheet caused by rolling with a fire cracked roll. Fire cracks will develop when a roll is not properly cooled. 

A coating defect consisting of the undissolved particles in the coating usually surrounded by a circular crater. The particles are usually resinous and are raised up from the cured surface with the appearance of the eye of a fish. 

That part of the die used to reduce a portion of the stock to the appropriate form of the forging 

This consists of heating the steel to a temperature above the transformation range, holding for one or two hours, and then cooling at a predetermined rate to obtain the desired microstructure. This process is used when it is desired to refine the grain structure and produce a lamellar pearlite. 

Hot rolled pickled steel that is cold reduced to a specified thickness and subject to no further processing (not annealed or temper rolled). The product is very stiff; it is intended for flat work where deformation is very minimal. 

Full Hard Cold Rolled steel produced to a Rockwell hardness of 84 and higher on the B scale. 

Steel coated with a thin layer of zinc to provide corrosion resistance in underbody auto parts, garbage cans, storage tanks, or fencing wire. Sheet steel normally must be cold-rolled prior to the galvanizing stage. Hot-dipped. Steel is run through a molten zinc coating bath, followed by an air stream "wipe" that controls the thickness of the zinc finish. Electro-galvanized. Zinc plating process whereby the molecules on the positively charged zinc anode attach to the negatively charged sheet steel. The thickness of the zinc coating is readily controlled. By increasing the electric charge or slowing the speed of the steel through the plating area, the coating will thicken. Differences. Electro-galvanizing equipment is more expensive to build and to operate than hot dipped, but it gives the steel maker more precise control over the weight of the zinc coating. The automotive manufacturers, because they need the superior welding, forming and painting ability of electro-galvanized steel, purchase 90% of all tonnage produced. 

A siliceous refractory material used in acid furnace. 

In this test, a projectile is dropped from a particular distance to dent the steel to various depths. The impact is measured in inch-pounds, and the coating adherence is determined by assessing flaking or crazing on the convex side of the cup. 

Industry-standard code that indicates quality tolerance of the thickness of the steel. 

Iron oxide, having a composition Fe2O3, corresponding to 69.94% of iron and 30.06% of oxygen, specific gravity 5.26, occurring in nature in igneous, metamorphic, and sedimentary rocks as a product of the weathering of magnetite and associated with varying amounts of impurities.

Internal ruptures in steel caused by stresses which arise from the combination of several factors, such as volume changes due to transformation, brittleness due to the presence of hydrogen, and the arrangement of the micro-structure, resulting from hot working. The size of such ruptures may vary considerably but they are usually comparatively short in length when viewed on a surface cut at right angles to the plane of defect and generally are so fine that they cannot be discerned other than after etching or by magnetic crack detection.

Cold Rolled steel produced to a Rockwell hardness range of 70 to 85 on the B scale. Product of this temper is intended for limited cold forming and will only withstand 90-degree bends made across the rolling direction. 

See Slips. 

A cylindrical or rectangular inner cover placed over the coils prior to placing the furnace on the base in the Batch Anneal. 

What Altering the properties of steel by subjecting it to a series of temperature changes. 

Why To achieve the desired microstructural / mechanical properties like the hardness, strength, or ductility of steel or alloys so that it is suitable for additional applications. How The steel is heated and then cooled as necessary to provide changes in the structural form that will impart the desired characteristics. The time spent at each temperature and the rates of cooling have significant impact on the effect of the treatment. 

The loss of material by scaling in a reheating or hot working process.

A condition caused by too much coating being applied to the strip. 

A mixture of hydrogen and nitrogen gas used to prevent oxidation and to clean the strip during the annealing process.

Coil type indicating that a produced coil or lift has problems that need to be resolved by the Quality Assurance department.

Also called ‘revert scrap’, it includes such items as pit scrap ; ingots too short to roll; rejected ingots; crop ends from slabs, blooms and billets; shear cuttings from trimming flat-rolled products to specified size; products irrevocably damaged in handling or finishing; ends cut from structural shapes, rails, bars, pipe or tubing to bring them to standard or exact ordered lengths; turnings from machining operations, broken moulds; obsolete machinery, dismantled buildings, steel shot recovered from slag, and so on. Bloom and slab crops constitute the largest single item of home scrap.

Holding at high temperature to eliminate or decrease chemical segregation by diffusion. 

A short bend or curvature caused either by improperly adjusted delivery guides or by any obstruction which may halt momentarily the forward motion of the bar from one roll stand to another.

A quality of wrought iron specifically manufactured for horse shoes.

A coil of steel rolled on a hot-strip mill (hot-rolled steel). It can be sold in this form to customers or further processed into other finished products. 

Direct reduced iron that has been processed into briquettes. Instead of using a blast furnace, the oxygen is removed from the ore using natural gas and results in a substance that is 90%-92% iron. Because DRI may spontaneously combust during transportation, HBI is preferred when the metallic material must be stored or moved.

Determination of the number, kind, size, and distribution of non-metallic inclusions.

A process in which the heating is done by eddy currents generated in the charge by the induction coil surrounding the charge. Depending upon the frequency used, the process is called low frequency, medium frequency and high frequency melting.

A form of semi-finished steel. Liquid steel is teemed (poured) into vertical cast iron moulds, where it slowly solidifies. Once the steel is solid, the mould is stripped, and the 25- to 30-ton ingots are then ready for subsequent rolling or forging.

A longitudinal plane of relatively impure steel arising from segregation occurring in the region of a corner of an ingot.

Very low carbon steel generally made in the open hearth in which all the other elements are removed to the maximum extent possible. Some of the commercial products falling under this group have less than 0.1 percent of all elements put together.

The container, usually made of cast iron, into which molten steel is poured and allowed to solidify.

What Inmetco is a coal-based process similar to FASTMET that uses iron oxide fines and pulverized coal to produce a scrap substitute. Mill scale and flue dust, inexpensive byproducts of steel making, can be mixed with the iron oxide fines. Inmetco, unlike other direct reduction products, is intended to be hot charged into an EAF, with attendant energy savings. How The process includes three steps. First, iron oxide fines, pulverized coal and a binder are formed into pellets. Second, the pellets, two to three layers deep, are heated in a gas-fired rotary hearth furnace for 15-20 minutes to produce sponge iron. Subsequently, the iron must be desulfurized. The coal in the pellets provides much of the energy required in the second phase.

A measure of thickness, and refers to those hot rolled sheets having thickness from 0.56 to 0.4 mm. 

This process is an extension of the LD process developed in Belgium whereby lime powder is introduced vertically into an LD converter along with the oxygen in order to make the LD process suitable for refining high phosphorus (up to 2 percent) bearing molten pig iron. 

A process of steel making where the impurities are oxidized by blowing high purity oxygen through a lance at supersonic speeds vertically on the surface of the molten pig iron held in a stationary basic lined converter which itself is kept vertical. 

A process to anneal wire, it consists of drawing the wire through a bath of molten lead heated to the proper temperature. 

Delivery time for an item of inventory to be moved from a source location to a destination via a specific route. Detail is specific to the level of the location. Also the time to produce a customer’s order from order placement to shipment. 

The process by which a leveling machine flattens metal strip, coil, or sheets beyond its yield point by bending it up and down over the interrupting arcs of upper and lowers sets of long, slender work rolls. Machines generally employ 17, 19, or 21 relatively small diameter rolls whose deflection under load is controlled by additional back-up rollers and a rigid frame. 

A process to flatten any shape deficiencies (wavy edges and buckles) in the sheet, prior to final shipment. Most cold-rolled sheet initially has a crowned cross-section that, if such a shape is undesirable to the customer, must be flattened in the leveling line. 

Identifies groups of coils for a particular customer order to be processed at a certain time; identifies a particular group of coils to load. 

Steel with less than 0.005% carbon is more ductile (malleable): It is capable of being drawn out or rolled thin for use in automotive body applications. Carbon is removed from the steel bath through vacuum degassing. 

A condition that occurs when the coating thickness is less than customer specifications. 

Submerged roll in the pot used to stabilize the strip as it exits the pot before entering the dies.

Steels which are especially suited for extremely cold climates and for the handling of relatively ‘warm’ (to –100o) liquefied gases such as propane, anhydrous ammonia, carbon dioxide and ethane. 

The original method of sealing the doors of coke ovens by trowelling and smoothening ground ‘mud’ into the V-shaped opening between the door and the door jamb. In recent years, there have been developed self-sealing doors that do not require luting.

Naturally occurring magnesium carbonate (MgCO3) containing small amounts of silica, alumina and iron oxide, and is used in making banks and bottom of a basic furnace, as well as during its fettling. 

The rock name applied to bedded sedimentary iron formations in which the principal iron mineral is magnetite. It is a hard, dense, compact, fine-grained rock, commonly containing from 40 to 55% silica and 15 to 35% iron in the form of magnetite. Magnetite taconite ores are concentrated by magnetic methods after fine grinding. 

These are an example of alloy electrical steels. The outstanding property of these steels is their retentivity or ability to retain magnetism. Cobalt, chromium, and tungsten are the alloying elements commonly used to enhance this characteristic. 

The term usually means malleable cast iron but it is sometimes applied to wrought iron also. 

Annealing white cast iron so that some or all of the combined carbon is transformed into graphite or, in some instances, so that part of the carbon is removed completely. 

A round bar, usually slightly tapered, inserted through the forging and not supported at the ends, and around which a tube, ring or drum is forged between the upper & lower tools of the hammer or press. The mandrel governs the internal diameter. 

his is a measure of labor efficiency i.e. the ratio of total hours worked by steel employees to the tons shipped for a given period of time. Changes in the inventory level and work that is contracted out will affect the reported measurement. 

1. A hardening procedure in which an austentized ferrous material is quenched into an appropriate medium at a temperature just above the martensite start temperature of the material, held in the medium until the temperature is uniform throughout, although not long enough for bainite to form, then cooled in air. The treatment is frequently followed by tempering.

Small category of stainless steel characterized by the use of heat treatment for hardening and strengthening. Refers to a particular grain structure of steel which is extremely hard and consists of iron oxide precipitates in a ferrite matrix. Martensitic stainless steels are plain chromium steels with no significant nickel content. They are utilized in equipment for the chemical and oil industries and in surgical instruments. The most popular martensitic stainless steel is type 410 (a grade appropriate for non-severe corrosion environments requiring high strength). 

A batch process used to produce a zinc coating on manufactured steel items by shot peening. Small iron and steel parts are coated with zinc by drum-tumbling with a mixture of promoter chemicals, zinc powder, and glass beads. The tumbling action peens the zinc powder onto the part. 

Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain; for example, the modulus of elasticity, tensile strength, and fatigue limit. These properties have often been designated as "physical properties," but the term "mechanical properties" is much to be preferred. These are determined by mechanical methods involving destruction or deformation or both, such as tensile test, bend test, impact test and hardness test. 

A stage in the steel making process when all the scrap charged has been melted. This term is also synonymous with cast, blow or heat. 

1. A group of commodity steel shapes that consist of rounds, squares, flats, strips, angles, and channels, which fabricators, steel service centers and manufacturers cut, bend and shape into products. Merchant products require more specialized processing than reinforcing bar. 2. A trade term for black bar.

A process used to produce a zinc coating on manufactured steel items by metal spraying. Zinc metal wire or powder is fed into a spray gun where it is melted and sprayed onto the part to be coated. Melting is accomplished either by combustion in an oxygen-fuel gas flame or an electric arc. Combustion gases and/or auxiliary compressed air provide the necessary velocity to spray the liquid metal onto the part. 

The nitrogen case-hardening process which consists of subjecting machined and heat-treated parts to the action of a nitrogenous medium, commonly ammonia gas, at temperatures of about 510o to 538o. The outer layer of a conventionally nitrided case contains a shallow (0.05mm) but very brittle ‘white layer’ consisting or iron and other nitrides. Quenching is not required to produce a hard case. 

Obsolete steel scrap grade, at least one-quarter inch in thickness and in sections no larger than five feet by two feet. Much of the metal comes from demolished buildings, truck frames and heavy duty springs. Mini-mills are primary consumers of No. 1 heavy scrap.

Little to no change in mechanical and physical properties over time; Yield point elongation is zero. See Aging. 

A product to which oil has been applied to retard rusting. 

Measure of the amount of oil applied to a flat rolled steel product; for Tin Mill Products, the measure is grams/base box; for Sheet Products, the measure is oz./sq.ft. (or gm./sq.m.). 

The application of a surface layer of lubricant intended to retard rusting on sheet products and lubrication on Tin Mill products. 

A test used to obtain an indication of the drawing properties of the base metal as well as the adherence of the coating. In this test, the male and female dies are used to deform the steel into a cup shape. The force draws the metal into the die slowly so the coated sheet stretches to conform to the shape of the die. The depth of the cup is measured when the steel fractures, and the coating is then examined. 

Annealing of a sheet coil in the form of a loosely wound coil with or without a metal spacer between successive laps of the coil, thus providing gap for the atmosphere to circulate around each lap of the coil. This form of annealing is generally used for decarburisation annealing and / or nitriding, that is, annealing simultaneously with decarburisation and denitriding to produce extra low carbon and low nitrogen steels. Generally it is carried out in Bell type furnaces, but when carried out in Bogie Hearth Furnaces, the process is usually termed as ‘unitised annealing’.

A broad, dish-shaped, shallow hearth to refine pig iron and scrap into steel. Heat is supplied through convection from a large, luminous flame over the surface of the metal and by radiation from the roof, and the refining takes seven to nine hours. Open Hearths, at one time the most abundant steel making furnaces among integrated companies, have been replaced by the basic oxygen furnace. 

Organosols contain poly-vinyl chloride (PVC) dispersed in solvents. At temperatures of 325-350o F (165-175o C) the vinyl particles coalesce and dissolve in the plasticizers to form homogeneous films with good hardness, toughness and adhesion. 

A method of winding narrow strip steel over a much wider roll. Customers want to have as much steel on a coil as will fit in their machines, so they can spend less time moving the material and more time using it. By coiling the strip like fishing line (or thread) over a spool, a much longer strip can fit onto a coil of proper diameter. Oscillate-wound coils allow the customer to enjoy longer processing runs. 

Aging under conditions of time and temperature greater than those required to obtain maximum change in a certain property. See also aging. 

Heating to such a high temperature that an undesirably coarse grained structure is produced. Severe overheating may result in the properties being permanently impaired. 

Results from line delays which permit sections of the steel to remain in the acid too long. Causes pronounced chemical attack, resulting in pitting and roughness on the surface. 

Rust, corrosion. See Red Rust and White Rust. 

Enrichment of blast air with oxygen to increase hot metal production in the blast furnace. For every percent of oxygen above the normal air blast (21%), the production rate can be increased about 2 to 4%. 

Pure oxygen is injected into the molten steel during top-blown oxygen steel-making process through a tubular, water-cooled, copper-tipped retractable lance kept perpendicular above the center of the bath. At the top of the lance, armored rubber hoses are connected to a pressure-regulated oxygen source and top a supply of re-circulated cooling water. The tip of the lance contains from three to five converging-diverging nozzles to impart a supersonic velocity (mach 1.7 to 2.3) to the gas jets exiting normally under a pressure between 140 to 180 psi. 

The steel is packed in boxes with carbonaceous solids, sealed to exclude the atmosphere, and heated to about 927oC for a period of time depending upon the depth of case desired. A time of about 8 hours at 927oC results in a case depth of about 1.6mm.

An elongated area of segregated phosphide which revealed on etching. 

1. An operating unit that removes iron oxide from a hot rolled product by immersion into a hydrochloric or sulfuric acid solution. 2. The pickler tank contains 5-6% concentrations of sulfuric acid. This solution is kept at a temperature of 180-190o F. The purpose of the pickler is to complete the preparation of the steel for plating, by removing any oxides from the surface.

What Process that cleans a steel coil of its rust, dirt and oil so that further work can be done to the metal. 

Why When hot-rolled coils cool, rust forms on the unprotected metal; often coils are stored or transported while exposed to outside air and water. How Through a continuous chemical or electrochemical process, the steel is uncoiled and sent through a series of hydrochloric acid baths that remove the oxides (rust). The steel sheet is then rinsed and dried. 

Making a hole with a tapered and pointed tool without removal of metal. 

Introduction of carbon in the steel bath by the addition of pig iron. 

The name for the melted iron produced in a blast furnace, containing a large quantity of carbon (above 1.5%, usually between 3% to 4.5%), along with silicon, manganese, phosphorus, and sulphur in varying amounts depending upon the quality of raw materials used and solidified in moving metal moulds of a Pig Casting Machine. Pig iron is used in the foundry or for conversion into steel. Named long ago when molten iron was poured through a trench in the ground to flow into shallow earthen holes, the arrangement looked like newborn pigs suckling. The central channel became known as the "sow," and the moulds were "pigs."

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A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite. 

This treatment is given in addition to annealing in order to develop the optimum mechanical properties and in place of annealing when the amount of machining or cutting to be done is not great. It consists of first heating the steel above the critical range, and then cooling it rapidly by immersing it in a liquid cooling medium such as oil or water. This is followed by heating the steel to an intermediate temperature, very seldom higher than 650oC and usually somewhat lower. 

Working with a rabble, that is, the tool provided for stirring the molten metal bath in a puddling furnace with cinder to assist purification. 

A series of grooves usually horizontal, made in the surface of a roll in order to assist the roll to bite the steel and to prevent skidding between the roll and the work. Ragging is usually found in roughing and forming passes. 

Tank of water used to quickly cool the strip before it reaches the delivery end of the line. 

The lanthanide metals of the periodic table (atomic nos. 57 to 71) are also known as rare earth metals. 

The removal of the ragged inside edge at the ends of cut tubes.

The adjustment of carbon content of molten steel by addition of carbonaceous material, high-carbon pig iron or a high-carbon alloy. 

Annealing cold-worked metal to produce a new grain structure without a phase change. 

The approximate minimum temperature at which recrystallization of a cold-worked metal occurs within a specified time. 

The waste flue gases from high temperature processes contain the sensible heat of vapourisation of water (apart from the latent heat, which is not practical to recover) which is recovered in a recuperator by transfer of heat continuously from one fluid to another. 

A commodity-grade steel used to strengthen concrete in highway and building construction. 

The process of replacing the refractory lining of a liquid steel vessel. Once it wears out, the brick lining of a furnace must be cooled, stripped and replaced. This maintenance can be significant because a blast furnace reline may require up to three months to complete. 

Reversion of or addition of phosphorus into steel under steel making practice.

The impurities in mini-mill steel as the result of the mix of metals entering the process dissolved in obsolete scrap. Residuals are key concerns regarding the mini-mills' recent entry into the flat-rolled market, where high residuals can leave sheet steel too brittle for customer use. 

Mill stands place considerable pressure on slabs, blooms and coils to further process the material. There are two general ways of applying the force to the steel‹screw and hydraulic systems. 

Screw (Incline Plane) This older method used the basic principle of the screw to adjust the space between the mill rolls. Because metal touches metal, these configurations will wear down over time and can cause quality problems. 

Hydraulic (Pancake Cylinder) This modern system uses fluid pressure to rapidly adjust the roll spacing several times per second. These minute, instantaneous adjustments allow for superior gauge tracking and higher-quality products. 

Periodic surface defects due to some imperfection on the surface of a roll or due to particles of matter picked up by rolls. 

Openings of definite shapes formed between a set of rolls through which hot steel passes for taking up the given shape or undergoing a desired amount of reduction in sectional area. This term also applies to a single passage through a pair of rolls for the purpose of altering the shape and / or reducing the cross-sectional area. 

Ferrous (iron-containing) material that generally is re-melted and recast into new steel. Integrated steel mills use scrap for up to 25% of their basic oxygen furnace charge; 100% of the mini-mills' raw material for their electric furnaces generally is scrap. 

Home (Revert) Scrap Waste steel that is generated from within the steel mill, through edge trimming, rejects and metallic losses in slag. It normally is sent directly back to the furnace. Prompt (Industrial) Scrap Excess steel that is trimmed by the auto and appliance stampers and auctioned to scrap buyers as factory bundles. This is a high-quality scrap as the result of its low-residual content and consistent chemistry. Obsolete (Reclaimed) Scrap Iron-bearing trash. Automobile hulks, worn-out refrigerators and useless storage tanks, for example, can be recovered from the junkyard and re-melted. The residual impurity of such scrap normally relegates obsolete scrap to the mini-mills (see No. 1 Heavy Melt). 

Free cutting steel bars suitable for the manufacture of bolts and screws. 

A form of adhesive wear that produces superficial scratches or a high polish on the rubbing surfaces. It is observed most often in inadequately lubricated parts. 

Steel that does not meet the original customer's specifications because of a defect in its chemistry, gauge or surface quality. Mills must search to find another customer (that can accept the lower quality) to take the off-spec steel at a discount. While secondary will not affect the reported yield, margins will suffer. 

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A mashed or deformed end on a bar caused by defective or improperly adjusted shearing equipment. 

Specified Thickness in Inches Specified Width in Inches

  Up to 6 Over 6 to 8 Over 8 to 12 Over 12 to 48 Over 48

0.2300 + Bar Bar Plate Plate                          Plate

0.2299 - 0.2040 Bar Bar Plate Plate                  Plate

0.2039 - 0.1800 Strip Strip Strip Sheet                 Plate

0.1799 - 0.0449 Strip Strip Strip SheetSheet  

A type of specialty steel created by introducing silicon during the steel-making process. Electrical steel exhibits certain magnetic properties (such as greatly increased electrical resistivity, high permeability and greatly reduced core losses), which make it optimum for use in transformers, power generators and electric motors. They are of two types :

Grain-Oriented The metal's grain runs parallel within the steel, permitting easy magnetization along the length of the steel. Although grain-oriented steel may be twice as expensive to produce, its magnetic directional characteristics enable power transformers, made from this metal, to absorb less energy during operation. 

Non-Grain-Oriented Because there is no preferential direction for magnetization, non-grain-oriented steel is best used in rotating apparatus such as electric motors. 

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A process that combines iron-bearing particles, once recovered from environmental control filters, into small pellets. Previously, these materials were too fine to withstand the air currents of the smelting process and were thrown away. The iron is now conserved because the chunks can be charged into the blast furnace (see Agglomerating Processes). 

Steel that is the entry material to a pipe mill. It resembles hot-rolled strip, but its properties allow for the severe forming and welding operations required for pipe production. 

Visibly colder "stripes" on slabs caused by contact with water-cooled skids in a pusher-type reheat furnace. Walking beam reheat furnaces eliminate skid marks. 

Holes visible on ingot surface.

Passing hot-rolled, annealed or normalized sheets in cold state through rolls for removing kinks, stretcher strains or similar surface conditions, develop mechanical properties, and/or reduce the tendency of stretcher strain or fluting during forming. the cold deformation being very light. Usually reduction is less than 5 percent. 

Solidified metal with some amount of slag and refractories remaining in furnace or ladle after the molten metal is poured out. It may also refer to the film formed inside a mould after casting. If detached, it may get entrapped and lead to skull patches. 

Whenever gas passes through a liquid, the liquid expands due to the presence of the gas. During steel-making, oxygen lancing causes formation of stable slag foam bubbles on top of the molten hot metal. While some foam is desirable to help capture the energy from post combustion, excessive foaming can lead to slopping in oxygen steel-making. On the other hand, controlled foaming in the electric arc furnace is desirable to protect the refractories from the electric arc radiation. 

A full width sample of chemically treated steel saved for metallurgical testing. 

A defect on the plate causing a discoloration of the plate.

Precipitation etching that causes contrast by distinctive staining of micro-constituents; different interference colors originate from surface layers of varying thickness.

The term for grades of steel that contain higher (more than 10%) chromium, with or without other alloying elements. By AISI definition, a steel is called "Stainless" when it contains 4% or more chromium. Stainless steel resists corrosion, maintains its strength at high temperatures, and is easily maintained. For these reasons, it is used widely in items such as automotive and food processing products, as well as medical and health equipment. The most common grades of stainless steel are: 

Type 304 The most commonly specified austenitic (chromium-nickel stainless class) stainless steel, accounting for more than half of the stainless steel produced in the world. This grade withstands ordinary corrosion in architecture, is durable in typical food processing environments, and resists most chemicals. Type 304 is available in virtually all product forms and finishes. 

Type 316 Austenitic (chromium-nickel stainless class) stainless steel containing 2%-3% molybdenum (whereas 304 has none). The inclusion of molybdenum gives 316 greater resistance to various forms of deterioration. 

Type 409 Ferritic (plain chromium stainless category) stainless steel suitable for high temperatures. This grade has the lowest chromium content of all stainless steels and thus is the least expensive. 

Type 410 The most widely used martensitic (plain chromium stainless class with exceptional strength) stainless steel, featuring the high level of strength conferred by the martensitics. It is a low-cost, heat-treatable grade suitable for non-severe corrosion applications. 

Type 430 The most widely used ferritic (plain chromium stainless category) stainless steel, offering general-purpose corrosion resistance, often in decorative applications.

A process where the entire coal charge to the coke oven is stamped, or compressed, and then pushed into the oven for coking. The main advantages are : increase in bulk density of the charge, enhancement of coking properties, usage of poorer quality coking coals, production of more abrasion-resistant coke, higher yield of blast furnace-size coke and higher throughput from the ovens. 

A technique used to predict when a steel-making function's quality may deteriorate. By tightly monitoring the product's variance from specifications, the operator can determine when to apply preventative maintenance to a machine before any low-quality (secondary) steel is produced.

A reversing steel sheet reduction mill with heated coil boxes at each end. Steel sheet or plate is sent through the rolls of the reversing mill and coiled at the end of the mill, reheated in the coil box, and sent back through the Steckel stands and recoiled. By re-heating the steel prior to each pass, the rolls can squeeze the steel thinner per pass and impart a better surface finish. 

For the purpose of classification, steel is an iron base alloy generally suitable for working to the required shape in the solid state having a carbon content generally less than 1.5 percent and containing varying amounts of other elements. A limited number of high alloyed steels may have more than 2 percent carbon but 2 percent is the usual dividing into between steel and cast iron. 

Center insert that keeps a coil from collapsing. Used on Double Reduced material. 

Small corrugated insert used to keep coils from collapsing before rewinding.

The amount of steel used per unit of gross domestic product. Intensity reflects the secular demand for steel, as opposed to cyclical demand. The amount of steel used in vehicles and the popularity of alternative materials affect the intensity, or how much steel is needed per unit produced. The state of the economy, however, determines the number of units. 

Banding and packaging material that is used to close and reinforce shipping units, such as bales, boxes, cartons, coils, crates, and skids.

Aging at two or more temperatures by steps, without cooling to room temperature after each step. Compare with interrupted aging and progressive aging. 

The joining up of two adjacent surfaces, due to partial welding of pack-rolled or batch-annealed sheets. 

Controlled deviation in dimensions in any particular region or place with respect to the remainder of the material. In rolls, sweep refers to the camber at the middle. In sheets, sweep refers to controlled dishing of a load of sheets for annealing to ensure flatness in the finally processed sheets. 

Making a forging of circular section between specially shaped concave tools. 

The texture or "pattern" of a steel surface determined by the grit on the roll or the grind on a brite roll.

A superficial defect that mars the surface of steel and is detrimental to the end use; examples include blisters and roll mark defects. 

The ground roll finishes are : 7B, a smooth finish, normally for melted coatings intended for special applications; 7C, the standard mill finish, for either melted or unmelted coatings is the finish used for most applications. The blasted roll finishes are 5B, a shot blast finish (SBF) with a melted tin coating; 5C, a shot blast finish with an unmelted tin coating, principally for crowns and closures; 5D, a shot blast finish with and unmelted tin coating primarily for drawn & ironed cans. 

Material applicable to the various classes of structures, indicated by the standard specifications, which is suitable for the different mechanical operations employed for the fabrication of such structures. Structural quality (the characteristics of which are defined in the standard specifications of the American Society for Testing Materials) represents the quality of steel produced under regular or normal manufacturing conditions.

Facility which produces hot rolled bands, hot rolled and pickled bands, cold rolled steels and cold rolled bands for further processing in Sheet Mill and Tin Mill. 

Filling of moulds with finished molten steel from the ladles. 

A coil that has not wound properly whose sidewall protrudes out. Tension problems or a bad start on the exit reel causes this condition.