Abrasive
A substance capable of removing material from another substance in machining, abrasion or polishing.
Abrasive Wear
The removal or displacement of materials from a surface when hard particles slide or roll across the surface under pressure. The particles may be loose or may be part of another surface in contact with the surface being worn.
Abrasion
The process of grinding or wearing away through the use of abrasives, a roughening or scratching of a surface due to abrasive wear.
Abrasion Rate
The rate which material is removed from the surface during abrasion. It is usually expressed in terms of thickness removed per unit of time or distance traversed.
Accelerated Cooling
Employed to improve resistance to impact (toughness) and refine the grain size of certain grades and thickness of plates. Such cooling is accomplished by fans to provide circulation of air during cooling, or by a water spray or dip.
Acid Bottom
Furnace bottom (hearth) of a melting furnace made of acid refractory such as silica bricks.
Acid Brittleness
Brittleness induced in sheet and strip pickled in acid solution to remove scale or during electroplating. This is commonly attributed to absorption of hydrogen.
Acid Fluxes
Used to remove unwanted basic impurities to form a fusible slag. Silica (SiO2), available as sand, gravel, and quartz in large quantities and in a sufficiently pure state, is the only substance that is used as a strictly acid flux.
Acid Process
A steel making process in which steel is refined under an acid slag in an acid refractory lined furnace or converter.
Acid Refractory
A refractory material, acidic in chemical composition and containing high proportion of silica, that is, silica sand and ganister.
Acid Steel
Steel made by acid process.
Adhesive Wear
The removal or displacement of materials from a surface by the welding together and subsequent shearing of minute areas of two surfaces that slide across the surface under pressure. In advance stages, may lead to galling.
Adjustable Mould Width
In order to minimize both the time required to change a mould as well as the mould inventory during slab casting, adjustable mould were first developed which could be adjusted without the mould being removed from the casting machine. More recently, as an alternative to slab slitting, the slab width can be changed during the actual operation. In one design, the mould taper can be adjusted by using different gear ratios for moving the top and bottom of the narrow mould faces.
A. G. C. System
(Automatic Gauge Control) Hydraulic or electric system th at supplies the force to the A.G.C. roll force cylinders.
Age Hardening
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.
Aging
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.
Agglomerating Processes
Fine particles of limestone (flux) and iron ore are difficult to handle and transport because of dusting and decomposition, so the powdery material usually is processed into larger pieces. The raw material’s properties determine the technique that is used by mills.
Sinter Baked particles that stick together in roughly one-inch chunks. Normally used for iron ore dust collected from the blast furnaces.
Pellets Iron ore or limestone particles are rolled into little balls in a balling drum and hardened by heat.
Briquettes Small lumps are formed by pressing material together. Hot Iron Briquetting (HBI) is a concentrated iron ore substitute for scrap for use in electric furnaces.
Nodules Fine iron bearing materials moving through a rotary kiln are formed into nodules or lumps by the rolling of the charge heated to incipient fusion temperatures.
Air Hardening
Hardening by cooling in air or gas at ambient temperature from a temperature above the transformation range.
Air Heater Tubes
Tubes used for heating air by means of hot gases, the air passing either inside or outside the tubes.
AISI (American Iron and Steel Institute)
An association of North American companies that mine iron ore and produce steel products. There are 50 member companies and more than 100 associate members, which include customers that distribute, process, or consume steel. The AISI has reorganized into a North American steel trade association, representing the interests of Canada, Mexico, and the United States.
Alkaline Cleaner
Uses an alkaline solution, usually sodium hydroxide, to clean residual oils and iron fines left on the strip from the cold reduction process.
Alkyd
A type of resin made from a polyhydroxy alcohol combined chemically with the acids of various oils. They are particularly adapted for use where hardness and high gloss are required. Used largely for outside decoration.
Alligatoring
The longitudinal splitting of flat slabs in a plane parallel to the rolled surface. Also known as fishmouthing.
Alloy
A substance having metallic properties consisting of two or more elements in which the major constituent is metal, or of metallic and non-metallic elements which are miscible with each other when molten, and have not separated into distinct layers when solid.
Alloying Element
An element (metal or non-metal) added during the making of steel for the purpose of increasing corrosion resistance, hardness, or strength. The metals used most commonly as alloying elements in stainless steel include chromium, nickel, and molybdenum.
Alloy Steel
An iron-based mixture is considered to be an alloy steel when manganese is greater than 1.65%, silicon over 0.5%, copper above 0.6%, or other minimum quantities of alloying elements such as chromium, nickel, molybdenum, vanadium, lead, niobium or tungsten are present. An enormous variety of distinct properties can be created for the steel by substituting these elements in the recipe.
Alloy Tool Steels
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 :
- 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.
- Intermediate Alloy Tool Steels : These steels usually contain elements such as tungsten, molybdenum or vanadium, which form hard, were-resistant carbides.
- 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.
Alloy Surcharge
The addition to the producer’s selling price included in order to offset raw material cost increases caused by higher alloy prices.
Alumina
Aluminium oxide (Al2O3), a common constituent of many refractory materials used in steel making.
Aluminum Killed Steel (Special Killed)
Steel deoxidized with aluminum in order to reduce the oxygen content to a minimum so that no reaction occurs between carbon and oxygen during solidification.
Anneal
A process, consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften metallic materials, such as steel. This process also simultaneously produces desired changes in microstructure, as in other properties, such as improvement of mechanical or electrical properties, removing stresses, increase in stability in dimensions, facilitation of cold work, improving machinability, etc. Also see Continuous Anneal and Batch Anneal.
Annealing
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.
Anneal to Temper
A final partial anneal that softens a cold worked non-ferrous alloy to a specified level of hardness or tensile strength.
Anodes
Tin bars that are put in the plater cells and are important to the plating process in the Tin Mill.
API
American Petroleum Institute.
Arc Heating
A method of heating steel by electric current in which the current is passed through an ionized gaseous medium and the heat radiated by the arc generated is utilized. This practice can be applied through two methods : (a) arcs pass between electrodes supported in the furnace above the metal. In this method, known as indirect-arc heating, the metal is heated solely by radiation from the arcs. Or, (b) arcs pass from the electrodes to the metal. In this method, known as direct-arc heating, the current flows through the metal charge so that the heat developed by the electrical resistance of the metal, though relatively small in amount, is added to that radiated from the arcs.
Argon-Oxygen Decarburization (AOD)
What A process for further refinement of stainless steel through reduction of carbon content.
Why The amount of carbon in stainless steel must be lower than that in carbon steel or lower alloy steel (i.e., steel with alloying element content below 5%). While electric arc furnaces (EAF) are the conventional means of melting and refining stainless steel, AOD is an economical supplement, as operating time is shorter and temperatures are lower than in EAF steel making. Additionally, using AOD for refining stainless steel increases the availability of the EAF for melting purposes.
How Molten, unrefined steel is transferred from the EAF into a separate vessel. A mixture of argon and oxygen is blown from the bottom of the vessel through the melted steel. Cleaning agents are added to the vessel along with these gases to eliminate impurities, while the oxygen combines with carbon in the unrefined steel to reduce the carbon level. The presence of argon enhances the affinity of carbon for oxygen and thus facilitates the removal of carbon.
Argon Rinse
To homogenise the melt temperature and composition and also to assist the flotation of deoxidation products during ladle refining of steel, the argon is blown through the melt at a rate of 0.08-0.13 nm3/min for 3 to 5 minutes.
Argon Trim
To facilitate the dissolution of ladle additions during refining of steel, the argon is blown through the melt at a rate of 0.30-0.45 nm3/min.
Argon Stir
To achieve slag-metal mixing in ladle desulphurization of steel during refining, the argon is blown through the melt at a rate of 0.3-0.5 nm3/min.
Artificial Aging
Aging above room temperature.
ASTM
American Society for Testing and Materials. A non-profit organization that provides a forum for producers, users, ultimate consumers, and those having a general interest (representatives of government and academia) to meet on common ground and write standards for materials, products, systems, and services.
ASTM Standards
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.
Atmosphere Valve
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.
Atomic Hydrogen Welded Tube
Tube made by forming strip, usually of stainless or heat-resisting steel, into tubular form and welding the joint by the atomic hydrogen process.
Atomizing Steam
Low pressure steam which is introduced to the oil gun to help atomize the oil, to assist the burning process, and to keep the oil gun from plugging.
Attemperator
Header connecting the primary and finishing superheaters into which feed water is sprayed to control the final temperature of the steam leaving the boiler.
Austempering
Cooling (quenching) an austenitised steel at a rate high enough to suppress formation of high temperature transformation products, then holding the steel at a temperature below that for pearlite formation and above that for martensite formation until transformation to an essentially bainitic structure is complete.
Austenite
Generally a solid solution of one or more alloying elements in a face centered cubic polymorph of iron (g iron). Specifically, in carbon steels , the interstitial solid solution of carbon g iron.
Austenitic
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).
Austenitic Grain Size
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.
Automatic
Describes the status of the operation when the O2 pulpit has control and the boiler logic has control.
Automatic Gauge Control
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 :
- Mathematical models that adequately describe the process.
- Instrumentation to measure the required variables of the system.
- Control equipment, including a digital computer, to perform the required functions for control of the system.
Auto Stamping Plant
A facility that presses a steel blank into the desired form of a car door or hood, for example, with a powerful die (pattern). The steel used must be ductile (malleable) enough to bend into shape without breaking.
Auxiliary Hydraulic System
Hydraulic system that supplies the force to run the various hydraulic cylinders associated with the finishing mill which are not taken care of by the A.G.C. or C.V.C. Hydraulic systems.
Auxiliary Oil Pump
A steam or electric pump that maintains oil pressure on the controls and the bearings of a turbo blower when it is not up to maximum speed.
Auxiliary Pump
Pump on the auxiliary system which supplies the pressure for the system.
AW-100
The hydraulic oil used in all the hydraulic systems located in the finishing mill oil cellar and the furnace hydraulic system.
Back Drafting
Taking the blast furnace out of blast for short periods, often less than 2 hours, (instead of banking) to perform various maintenance functions such as replacing tuyeres or repairing skip cables. This is done usually by opening the chimney valve and the hot-blast valve to a stove that has already been prepared by heating it to temperature and then shutting off the gas valve. As the furnace gas is drawn back into the stove, air is admitted through the peep sights and stove burner, and the operator makes certain that the gas burns in the stove. During the operation, the bleeders at the top of the furnace also are opened to pull some of the furnace gas out through the top.
Baking
Heating after pickling /or pickling and coating to remove hydrogen.
Balanced Steel (Semi-Killed and Semi-Rimmed Steel)
Steel to which controlled amounts of deoxidizers have been added in the liquid stage during tapping and teeming, the object being to reduce the severity of piping. This steel is intermediate between killed and rimming types.
Band
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.
Banding
Inhomogeneous distribution of alloying elements or phases aligned in filaments or plates parallel to the direction of working.
Banking
Shutting down the blast furnace for few days. The blast is taken off, the blowpipes are dropped and the tuyere openings are plugged with clay to prevent air from drafting through. Thus, hearth heat is preserved and the furnace can be returned to operation with a minimum effort.
Bar
Finished product of solid section generally supplied in straight length, which are rolled from billets and may be rectangular, square, flats, channels, round, half round or polygonal. The bars may be supplied in coil form also. The dimensions generally conform to the following :
a. Rounds and Half-Rounds : Minimum diameter 5mm.
b. Squares and Polygonal : Minimum 6mm side.
c. Flat Bar (Flat) : A finished product, generally of cross section, with edges of controlled contour and thickness 3mm and over, width 400mm and below and supplied in straight lengths. The product shall have rolled edges only (square or slightly rounded). This group also includes flat bars with bulb that has swelling on one or two faces of the same edge and a width of less than 400mm.
Bar Hold
The end of a bar or forging so reduced as to accommodate a porter bar or tongs for manipulation during forging.
Bare Spot
A location on the strip where coating did not adhere.
Barrel
The part of a forging of major cross section, the length of which usually exceeds the diameter.
Basal Crack
A crack in the ingot base caused by restriction to free contraction during solidification.
Base Box
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.
Base Metal Contamination
Dirt or other impurities in the steel strip.
Base Size
The intermediate size in which wire is annealed before drawing; in case of drawn galvanised or drawn tinned wire, the size in which it is galvanised or tinned.
Base Type
Type of base used for cooling; i.e., water or fan.
Base Weight
Tin Mill term; Thickness divided by .00011. Also weight in pounds of one Base Box of tin plate. In finished inventory, base weight is specified instead of decimal thickness.
Basic Flux
Used to remove unwanted acidic impurities to form a fusible slag. The chief natural basic fluxes are limestone, composed primarily of calcium carbonate (CaCO3), and dolomite, composed primarily of calcium-magnesium carbonate (Ca, Mg)CO3.
Basic Oxygen Furnace (BOF)
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.
Basic Oxygen Process (BOP)
A process in which molten steel is produced in a basic lined furnace by blowing oxygen into molten iron, scrap and flux materials. The furnace is known as Basic Oxygen Furnace (BOF).
Basic Process
A steel making process in which steel is refined under a basic slag in a basic refractory lined furnace or convertor.
Basic Refractory
A refractory material basic in chemical composition and containing high amounts of such oxides as lime and magnesia, for example, calcined dolomite or magnetite.
Basic Steel
Steel made by basic process.
Basis Weight
See Base Weight.
Batch Anneal
The process by which a large, stationary stack of steel coils (4 coils high) is subjected to a long heat-treating cycle. This process enables the cold-rolled sheet to fully recrystallize into the softest possible product conforming to customer specifications. Controlling the recrystallization process makes a fine-grained microstructure easy to obtain, and minimizes the tendencies for retention of directional properties of the rolled steel which could produce undesirable shapes in the stamping of a cylindrical part such as a can. Also see Anneal and Continuous Anneal.
Batch Pickling
Pickling of steel sheets and other light-gauge sheared lengths performed with specialized equipment in which a batch of sheets are processed together. Agitation of acid bath is employed as a means to increase the pickling rate.
Bath Sample (Spoon Sample)
A sample taken from molten steel in the furnace, for estimation and analysis of constituents.
Bead Test
Commonly used for testing coating adherence, especially on light-gauge material. A bead is used to deform the steel such that the sample contains a continuous ridge.
Becking
Forging the wall of a steel ring between a top becking tool and a becking bar to increase the internal diameter with or without an increase in the external diameter.
Belly Band
The band (strapping) that goes around the outside diameter of a coil.
Bench Drawn
Bars bright drawn in straight lengths on a draw bench.
Bender
Device used in drop forging hammer dies to bring the several sections of the stock or prepared blank into alignment.
Bend Tests
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.
Bessemer Process
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.
Best Patented Steel Wire
Rope wire drawn to tensile strength of 128 to 147 kgf/mm2.
Best Plough Steel Wire
Patented rope wire drawn to a tensile strength of 155 to 170 kgf/mm2.
Bevelling
Refers to pipe; the end preparation for field welding of the joint.
Bi-Coil
Also BY-COIL. Tin Mill term. Customers buy “by coil” or “bi-coil” rather than cut sheets.
Billet
A semi-finished steel form that is input material for manufacturing long products: bars, channels or other structural shapes. A billet is different from a slab because of its outer dimensions; billets are usually square and not exceeding 125×125 mm in cross section with rounded corners, while slabs are 750-1000 mm wide and 50-250 mm thick. Both shapes are generally forged or continually cast or rolled in billet mill / slabbing mill from ingots, but they may differ greatly in their chemistry.
Binders
Soft wire used for tying bundles or coil of wire.
Binders
Binders are used to impart strength to the refractory during manufacture or in service. These are of 4 types :
d. Temporary Binder : Their function is to improve handling strength during manufacture. Temporary binders include paper byproducts, sugar, or certain clays.
e. Chemical Binder : They impart strength during manufacture, after manufacture, or on installation as a monolithic material. Chemical binders include resins, starches, synthetic clays, waxes etc.
f. Chemical Binders : Chemical binders set hydraulically when mixed with water. The primary binders of this type used in refractories are the calcium-aluminate cements which set rapidly and are able to retain some of their bonding strength to intermediate temperatures.
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.
Biological Oxidation
The most commonly applied technology for final treatment of coke plant waste waters which have significant levels of phenol, cyanide, and ammonia, plus lesser concentrations of other organic compounds, primarily as a result of condensation from coke oven gases. The process consists of two stages : in an aeration basin, a mass of microorganisms in the form of suspended solids called an ‘activated sludge’ is supplied with oxygen, which enables it to destroy the biologically degradable contaminants in the wastewater. The treated water overflows to a clarifier, where the activated sludge is settled out to be recycled back to the aeration basin. The overflow water from the clarifier is discharged.
Bitumen Coating (Asphalt Coating)
An internal and / or external coating obtained either by dipping in a bath of molten asphaltic bitumen or by painting or dipping in a suitable asphaltic bitumen solution.
Bitumen Lining (Asphalt Lining)
An internal protection consisting of suitable bitumen, usually reinforced with inert mineral filler, applied hot by centrifugal means.
Bitumen Sheathing (Asphalt Sheathing)
An external protection consisting of bitumen reinforced with inert mineral filler which may be of a fibrous nature. The sheathing is applied hot.
Bituminous Solution
A paint made from bituminous materials dissolved in appropriate hydrocarbon solution.
Black Annealing
Annealing without any protective covering or using a controlled atmosphere. It is also termed as open annealing. Box annealing of ferrous alloy sheet, strip or wire.
Black Edges
The black colouration at the edges of annealed sheets and strips caused by oxidation or due to soot deposit.
Black Patches
Patches of scale left on sheet and strip surface due to unsatisfactory pickling.
Black Plate
- Any steel that has not been coated – usually has gone through Tandem Mill (cold-rolled). Also defines a product, uncoated material in tin plate gauges. 2. 128 lb. (.0141 in) and lighter tin mill product which has not received any additional metallic coating during production. 3. A low carbon cold reduced steel intended for use in the uncoated state or for coating with tin and chromium.
Black Iron
Uncoated steel product.
Black Sheet or Strip
Hot-rolled sheet or strip that is not descaled.
Black Softened
Hot- or cold-rolled sheet and strip softened by black annealing, but not yet descaled (and usually refers to stainless variety).
Blank Holder
The device used to hold the blank to prevent wrinkling of the edges during pressing or drawing.
Blanking
An early step in preparing flat-rolled steel for use by an end user. A blank is a section of sheet that has the same outer dimensions as a specified part (such as a car door or hood) but that has not yet been stamped. Steel processors may offer blanking for their customers to reduce their labor and transportation costs; excess steel can be trimmed prior to shipment.
Blast Furnace
A tall shaft-type furnace, with a vertical stack superimposed over a crucible-like hearth, lined with heat-resistant (refractory) bricks and used by integrated steel mills to smelt iron by reducing iron oxides present in ores and sinter into liquid hot metal by using coke as fuel and reducing agent. Its name comes from the blast of preheated air and gases blown from the bottom through water-cooled copper tuyeres and forced up through the iron ore, sinter, coke, and fluxes (limestone and dolomite) that load the furnace. Hot metal and slag are periodically tapped from bottom and gasses rising from the top are cleaned and used as fuel in the steel plant. Blast furnaces are rarely stopped but they can be slowed down or idled.
Blast Furnace Coke
The sized coke obtained from screening in the range of 25 mm to 80 mm which is suitable for charging in the blast furnaces.
Blast Furnace Gas
A by-product of the iron blast furnace. 2.5 to 3.5 ton of BF gas is generated per ton of the pig iron produced.
Blasting
A process of cleaning or preparing surfaces by high speed impact of abrasive particles, such as sand, chilled iron shot, or angular steel grit (generally called sand blasting, shot blasting or grit blasting).
Bleeding
- Escape of liquid steel through the bursting of the shell of a partly solidified ingot due to build up of pressure inside the solidifying mass, or escape of liquid from the core of an ingot, withdrawn from the mould before it has solidified sufficiently. 2. A coating defect consisting of the migration of an ingredient to the surface of a coating, or a migration, which stains in an adjacent area. The term blooming is also a form of bleeding – usually associated with lubricants rather than pigments.
Blister
- Coating defect consisting of the formation of bubbles in a coating, which appear as hemispherical elevations. The blisters are hollow, and are usually caused by entrapped air or solvent. 2. A raised spot on the surface on the surface of metal due to expansion of gas which causes a subsurface metal separation such as inclusions and small laminations.
Block Drawn
Wire drawn in coil on a block.
Block Off
- Wooden separators which are used at both the bottom of a lift and between IPM’s (bundles) of a lift. 2. The act of placing 4x4s between the lifts in the piler’s box.
Blocking
A coating defect consisting of the adhesion of two adjoining coatings or materials. Usually this term refers to the coating on one side of coated plate being tacky or sticky and adhering to the adjacent sheet.
Bloom (1)
A semi-finished forged, rolled or continuously cast steel form whose cross-section is square or rectangular (excluding slab) and is generally more than 125 x 125mm (or equivalent cross-sectional area). This large cast steel shape is broken down in the mill to produce the familiar I-beams, H-beams and sheet piling. Reduction of a bloom to a much smaller cross-section results in formation of billets. Blooms are also part of the high quality bar manufacturing process: reduction of a bloom to a much smaller cross-section can improve the quality of the metal.
Bloom (2)
A coating defect consisting of the migration of an ingredient, in the coating, to the surface of the cured film. Usually blooming refers to waxes or lubricants, which rise to the surface and cause a hazy appearance.
Blow Back
A coating defect consisting of a lower coating film weight on the bottom of the coated sheet caused by high velocity air in the oven. Blow back usually occurs with high solids coatings which have little solvent to evaporate and “set” the film.
Blow Hole (Gas Cavities)
Cavities in solid steel formed by entrapped gas bubbles during solidification.
Blowing Out
When a furnace has reached the end of its campaign (lining worn out), it is usually blown out except under most unusual circumstances. Or, if business conditions deteriorate to the extent production is no longer required, the decision may be made to blow out the furnace.
Blown Ingot
An ingot with pronounced blow holes.
Blown Metal
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.
Blue Annealing
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.
Blue Annealed Wire
Wire with scale free surface, but oxidised to a blue temper colour during annealing.
Blue Billy (Purple Ore)
The iron oxide residue from the manufacture of sulphuric acid from iron pyrites containing approximately 50% iron. It is used for fettling the puddling furnace.
Blued Edges
Blue or bluish-black oxidation colouration at the edges of sheets and strips arising during heat treatment in the absence of any protective medium.
Blush
A coating defect consisting of the whitening of a cured film which results in a translucent or opaque appearance with accompanying loss of gloss. Blushing usually occurs during the pasteurization or steam processing of films which are undercured or water sensitive.
Boiler Tubes (Smoke Tubes)
Tubes which form part of the heating surface of a boiler, as distinct from superheater tubes. The tubes may contain water and be surrounded by the furnace gases as in a water tube boiler, or they may act as flues and be surrounded by water as in smoke tube boiler.
Bolster
A dovetailed block of steel which rests on the base block of the hammer into which the bottom die is keyed.
Bonderizing
Treating cold rolled or galvanized steel surfaces with phosphate to improve paint-adherence.
Bonderized Coating
A thin film of phosphate pretreatment applied to a steel surface (bare or zinc coated) to enhance paintability.
Boss
A projection on the surface of a forging.
Bottling
Reducing the diameter at the end of a hollow forging to form a neck.
Bottom Blowing
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.
Bottom Casting (Trumpet Casting, Uphill Casting)
Simultaneous casting of a number of ingots by pouring the metal into a central refractory-lined tube or trumpet, whence it flows through refractory runners into the bottom of the moulds.
Bottom Fash (Bottom Flash, Bottom Fin)
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.
Bottom Plate (Bottom Stool)
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.
Bottom Splash (Bottom Shell)
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.
Bottom Stirring
Injection of essentially inert gases into the bottom of the BOF vessel, penetrating the bottom shell and the bottom refractory lining, under the molten bath, to agitate the molten masses for such purposes as homogeneity of the melt after introducing additions in the furnace and improving the interaction between the steel bath and the slag. There is usually no direct chemical reaction associated with bottom stirring. The gas injection is either by means of refractory material porous plugs embedded in the bottom lining, or by means of tuyeres, penetrating the bottom lining.
Box Annealing (Close Annealing)
A process of annealing a ferrous alloy in a suitable closed metal container, with or without packing material, in order to minimize oxidation. The charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly.
Bow
The greatest deviation from a straight line along a longitudinal edge in a sheet or strip.
Box Annealing
Annealing of a metal or alloy in a sealed container under condition that minimise oxidation. See black annealing also.
Brake Press Bending
An operation which produces various degree bends when fabricating parts from steel.
Breakage
Cracks or separation of the steel.
Breaker
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.
Breakout
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.
Breeze Coke
Smallest fraction of coke, less than 10 mm in size.
Bridging
See Slips.
Bridle Unit
A three-roll cluster used to control line tension at strategic locations on the line.
Bright Annealing
Annealing in a protective medium to prevent discoloration of the bright surface.
Bright Annealed Wire
Wire which has been annealed in a controlled atmosphere to prevent surface oxidation.
Bright Bar or Wire
Bar or wire with a bright finish obtained by cold drawing, machining, grinding etc.
Bright Ground
Bar or wire ground between abrasive wheels which give a bright finish to the material.
Bright Machined
Material which has been turned, ground, shaped or milled to size and finished with a smooth bright surface.
Bright Turned Rounds
a. Round hot rolled material which has been reduced in size by centreless turning and finished with a smooth bright surface
b. Round hot rolled material which has been turned between centres and finally finished. Turned material is generally cold rolled to remove tool marks.
Brinell Hardness Test
A test for determining the hardness of a material by forcing a hard steel or carbide ball of specified diameter into it under a specified load. The result is expressed as the Brinell hardness number.
Briquette Blending
Using non-coking or poorly coking coals by partially briquetting them with coking coals (and binder i.e. tar or pitch) to produce high-strength coke.
Brite
- Regular galvanize coating (not minimized spangle or JP). 2. Rolls that have no grit; smooth finish on surface of steel.
Brittle Fracture
Separation of a solid accompanied by little or no macroscopic plastic deformation. Typically, brittle fracture occurs by rapid crack propagation with less expenditure of energy than for ductile fracture.
Brittle Inter-metallic Layer
An iron-zinc alloy layer formed between the steel substrate and the free zinc of galvanized coatings.
Brittleness
Tendency to fracture without any visible sign of appreciable deformation.
Broken Backs
A band of traverse cracks along a drawn wire.
Bruise
A mark transferred to the strip surface from a defective process roll. Similar to dent or punchmark.
BSO
See Butyl Stearate.
Buckling
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.
Build Up Coil
A coil made by putting together two or more coils to make one max coil or one shippable coil.
Bundle
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.
Burdening
The regulation of the proportion of ore, pellets, sinter, flux, coke and miscellaneous materials charged into the blast furnace. Essential to keep the operation of the furnace at maximum efficiency and to control the hot metal composition.
Burden Ratio
In blast furnace, the ratio of iron-bearing materials per charge to the weight of coke.
Burned Steel
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.
Burning
(1) During austenitising, permanent damage of a metal or alloy by heating to cause incipient melting or intergranular oxidation.
(2) During subcritical annealing, particularly in continuous annealing, production of a severely decarburised and grain coarsened surface layer that results to excessively high temperature.
(3) In grinding, sufficient heating of the workpiece to cause discoloration or to change the microstructure by tempering or hardening.
Burnt Edges
Broken edges occurring during hot-rolling and caused by overheating or burning.
Burnt Rubber
Small or large black spots that generally show up on surface and are generally caused by pickling steel too hot.
Burr (Fash, Flash)
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).
Burr Mashers
Devices used to remove build up on edge of strip after the slitting process.
Burst Edges
Edges of sheet or strip ruptured due to excessive cold rolling.
Bushelling
- Steel scrap consisting of sheet clips and stampings from metal production. This term arose from the practice of collecting the material in bushel baskets through World War II.
- Compacting wrought iron turnings, borings and scrap into a bloom or slab by heating to a welding temperature and forging.
Butterfly
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.
Butt Weld
Weld made to join two strip ends set against each other.
Butt Welding
Joining two edges or ends by placing one against the other and welding them.
Butt-Weld Pipe
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.
Butyl Stearate (BSO)
A lubricant applied on electrolytic chromium coated steel.
By Coil
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.
By-Product Process of Coke Making
In this process, air is excluded from the coking chambers, and the necessary heat for distillation of coal is supplied from external combustion of some of the gas recovered from the coking process (or, in some instances, cleaned blast furnace gas or a mixture of coke oven and blast furnace gas).
Camber
- 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.
Camber Tolerances
Camber is the deviation from edge straightness. Maximum allowable tolerance of this deviation of a side edge from a straight line are defined in ASTM Standards.
Can Dimensions
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.
Capacity
Normal ability to produce steel in a given time period. This rating should include maintenance requirements, but because such service is scheduled to match the needs of the machinery (not those of the calendar), a mill might run at more than 100% of capacity one month and then fall well below rated capacity as maintenance is performed.
Engineered Capacity The theoretical volume of a mill, given its constraints of raw material supply and normal working speed.
True Capacity Volume at full utilization, allowing for the maintenance of equipment and reflecting current material constraints. (Bottlenecks of supply and distribution can change over time–capacity will expand or reduce.)
Capped Steel
It is a rimming steel in which the depth of the rim is controlled by arresting the rimming action, at the appropriate time. The rimming action can be arrested mechanically by putting a heavy steel plate on the top of the surface of the ingot (mechanical capping), or can be stopped by killing by the addition of decoxidizers on the ingot top (chemical capping). The rimming action can also be stopped by spraying water on the top of the ingot.
Capping (of Abrasive Particle)
A mechanism of deterioration of abrasive points in which the point become covered by caps of adherent abrasion debris.
Carbon Electrodes
Made from calcined petroleum coke or calcined low-ash anthracite coke, carbon electrodes are widely used in submerged-arc furnaces for the manufacture of ferroalloys, silicon metal, aluminum, calcium carbide, phosphorus, and so on because of their infusibility, chemical inertness, electrical conductivity, mechanical strength, and resistance to thermal shock.
Carbon Steel
An unalloyed steel. Steel that has properties made up mostly of the element carbon and which relies on the carbon content for structure. Most of the steel produced in the world is carbon steel. The plain carbon steels may also be classified on the basis of carbon content as hypoeutectoid (carbon content below the eutectoid value of 0.80%) or hypereutectoid (carbon content above this value)
Carbonitriding
A case hardening process in which a suitable ferrous material is heated above the lower transformation temperature in a gaseous atmosphere having a composition that results in simultaneous absorption of carbon and nitrogen by the surface and by diffusion, creates a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the workpiece.
Carburising
A process of introducing carbon into the surface of a solid piece of steel by heating and holding above the transformation temperature in contact with a suitable source of carbon which may be a solid, liquid or gas. On quenching after carburizing, the high-carbon ‘case’ becomes very hard, while the low-carbon core remains comparatively soft.
Cardboard Drum
Cardboard insert placed on the reel around which the coil is wound. The drum is used to eliminate damage in the center of the coil.
Case
That portion of a ferrous alloy, extending inward from surface whose composition has been altered during case hardening. Typically considered to be the portion of an alloy (a) whose composition has been measurably altered from original composition, (b) that appeared dark when etched, (c) that has a higher hardness value than the core.
Cased Tube
A close-joint tube of steel over which a close-joint or seamless or welded tube of another metal is drawn.
Case Hardening
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.
Casing (Oil Well Casing)
Tubes used for lining bore holes to prevent caving in of the surrounding strata and the undesired entry of water.
Casing
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.
Cast (Heat or Melt)
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.
Castables
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.
Cast Iron
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.
Casting
Pouring or teeming molten metal into moulds. This also refers to metal objects so procured.
Casting Ladle
A refractory lined receptacle in which liquid steel is received from the furnace for teeming purpose.
Cast Structure
The metallographic structure of a casting evidenced by shape and orientation of grains as well as segregation of impurities.
Casting Shrinkage
Contraction of a casting during solidification and subsequent cooling to ambient temperature.
Cast Steel
The term is used for steel castings.
Catastrophic Wear
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.
Catch Weight Coil
A coil of non-standard weight
Cathodic Sodium Dichromate
A common treatment applied to passivate the surface of electrolytic tin plate against the formation of tin oxides.
Cauliflower Top
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.
Caustic Cracking
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.
Cavitation Damage
Erosion of a solid surface through the formation and collapse of cavities in an adjacent liquid. Also known as cavitation erosion.
Cementite
A very hard and brittle compound of iron and carbon (Fe3C). It is characterised by orthorhombic crystal structure. Its occurrence as a phase in the steel alters chemical composition by presence of manganese and other carbide forming elements.
Center Buckle
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.
Chafing Fatigue
Fatigue initiated in a surface damaged by rubbing against another body.
Chamfering
The removal of sharp edges (the term is practically synonymous with ‘bevelling’ but has a less restricted application.
Channeling
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.
Charge
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.
Charging Box (Charging Basket)
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.
Charging Machine (Charger)
A ground or overhead travelling machine used for charging scrap in the steel making furnace such as open hearth.
Charging on the Main
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’.
Chattering
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
Cracked edges in sheet bars and strips occurring during hot-rolling.
Checking
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.
Cheese
A roughly cylindrical forging with convex sides formed by upending ingot or billet lengths between flat tools.
Chemical Treatment
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.
Chemically Brightened
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.
Chemistries
The chemical composition of steel indicating the amount of carbon, manganese, sulfur, phosphorous and a host of other elements.
Chill
An external zone of cementitic iron without appreciable graphite.
Chill Factor
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.
Chill Cracks
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.
Chilled Spring Wire
Wire drawn from quenched and age hardened mild steel.
Chipping
Removing surface defects by manual or pneumatic chisel.
Chop
A defect caused by metal being scrapped from the side of forging and hammered into the surface.
Chromite
A neutral refractory which is a double oxide of chromium and iron. The term is also used for a mineral containing chromic oxide and iron oxide.
Chromium
An alloying element that is the essential stainless steel raw material for conferring corrosion resistance. A film of chromium oxide that naturally forms on the surface of stainless steel self-repairs in the presence of oxygen if the steel is damaged mechanically or chemically, and thus prevents corrosion from occurring.
Cinder
The molten by-products produced in furnace used for bushelling or reheating. The chemical composition varies but is essentially silicate of iron.
Cinder Notch
Another name for slag notch.
Cinder Patch
This defect is the result of pick-up of material from soaking-pit bottoms, and generally has the appearance of a very scrabby bottom.
Circored
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.
Cladding
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.
Class 1 Surface Quality
A class of cold rolled steel processed to meet requirements for controlled surface texture, flatness, and temper requirements. Produced for exposed applications.
Cleaning Tank
This section of the plater is used to remove dirt, oil, grease, oxides and other contaminates from the surface of material to be electroplated. A cleaning agent is used at a temperature of 180-190 degrees.
Cleanliness
For internal steel quality, a measure of the size and frequency of inclusions; for external steel surface quality, a measure of the amount of extraneous materials (such as dirt, iron particles, carbon, etc.) on the steel surface.
Clean Steel
Steel which is obtained after secondary steel making (also referred to as Ladle Metallurgy’) and satisfies stringent requirements of surface, internal and micro-cleanliness quality and of mechanical properties.
Cleavage Fracture
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..
Clink
A rupture (internal or external) in ingot, bloom, billet, slabs, etc., caused by thermal stresses.
Clipping
Removing the fash.
Closing
Reducing the diameter of a tube, ring or hollow forging by pressing or hammering on a mandrel.
Coal Preheating
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.
Coating
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.
Coating Weight
- 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.
Coating Weight Test
A test of the weight of the coating measured 2 inches from each side of the strip and at the center.
Cogging (Roughing)
The action of reducing, by hot working, an ingot into a bloom or slab for subsequent rolling or forging.
Coils
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.
Coiling
The process of laying or winding the product in the form of coils
Coiled Bar
A long length of hot rolled bar produced in a continuous rolling mill and coiled in a manner similar to wire rod.
Coil Breaks
- A physical condition produced in the cooling tower or quench tank area of the line due to improper temperature control during cooling. 2. Creases or ridges which appear as parallel lines, transverse to the direction of rolling, and which generally extend across the width of the sheet. 3. A discontinuous curvature in the strip in the direction in which the material was rolled or uncoiled. Generally found in uncoiled hot rolled strip.
Coil End
ID of a coil that is left because of a defect. Ranging from 500 – 10,000 pounds. Anything 10,000 pounds and over get an IPM. A coil with a weight less than 5000 lbs. that does not meet customer specifications is called a salvage coil. These coils do not get an IPM number
Coil Line Markings
A light white-gray mark (square, circle, line, diamond, etc.) which has been placed on the strip by the platers. This mark serves as an indication to the feeder that the placement of the coil on the entry reel must be placed correctly to meet customer specifications (external customers request this mark to distinguish coating on the strip). The Feeder must refer to the scheduling book to determine how to place the coil on the entry reel for over or under wind.
Coil Number
Produced IPM Number assigned to a coil. IPM (In Process Material) Number.
Coil Set
A curvature of the strip in the lengthwise sense, parallel to the direction in which the strip was rolled or uncoiled.
Coining
Sizing a forging to close tolerances under a suitable press or hammer.
Coke
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.
Coke Oven Battery
A set of ovens that process coal into coke. Coke ovens are constructed in batteries of 10-100 ovens that maybe 20 feet tall, 40 feet long, and less than two feet wide. Coke batteries, because of the exhaust fumes emitted when coke is pushed from the ovens, often are the dirtiest area of a steel mill complex.
Coke Oven Gas
A by-product of coke manufacture, it is produced during the carbonization or destructive distillation of bituminous coal in the absence of air in the coke ovens. Approximately 310 cbm CO gas is produced per MT of coal coked in conventional high-temperature coking processes.
Cold Drawing
Reducing the cross-sectional area of a tube, when cold, by drawing through a die. The tubes are occasionally pushed through the die.
Cold Reduction
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.
Cold Reduction Mill
Sheet and strip are cold reduced to the desired thickness for the following reasons: 1) To obtain the desired surface. 2) To impart desired mechanical properties. 3) To make gauges lighter than the hot strip mill can produce economically. 4) To produce sheet and strip of more uniform thickness.
Cold Roll Base
Coils that are cold worked or reduced to gauge on the tandem mill.
Cold-Rolled Strip (Sheet)
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).
Cold Rolling (Cold Reduction)
Rolling steel (generally sheet or strip) below its recrystallization temperature with the degree of reduction being usually above 5%.
Cold Rolling Mill
A mill that reduces the cross sectional area of the metal by rolling at approximately room temperature.
Cold Shut (Teeming Arrest)
An ingot or casting defect resulting from interrupted flow of metal during pouring, causing a discontinuity in the skin.
Cold Sinking
Reducing the cross-sectional area and diameter of a tube by drawing when cold through a die.
Cold Strip Mill
A mill that rolls strip without first reheating.
Cold Work
Plastic deformation at such temperatures and rates that substantial increases occur in the strength and hardness of the metal visible structural changes include changes in grain shape and, in some instances, mechanical twinning or banding. The forces are relatively insensitive to the rate of application of loads and to temperature variations, but the basic strength of the worked metal is permanently increased.
Cold Working (Rolling)
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.
Collar
Part of a forging having a diameter greater than the adjacent portions but of a length less than its diameter.
Columnar Structure
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.
Combined Blowing
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.
Combined Carbon
That part of the total carbon in steel or cast iron present as other than free carbon.
Commercial Quality
Material of normally good quality for which limits of chemical composition and mechanical properties are more relaxed.
Commercial Tolerance
A range by which a product’s specifications can deviate from those ordered and still meet the industry accepted ranges (defined in ASTM Standards, etc.)
Condenser Tubes
Tubes used in the conversion of a vapour into a liquid by cooling.
Consumption
Measures the physical use of steel by end users. Steel consumption estimates, unlike steel demand figures, account for changes in inventories.
Contact Rolls
Metal rolls that are used in the chemical treatment area. Electricity goes through these rolls.
Continuous Anneal
A process by which the steel is rapidly heated, soaked and cooled at a confirmed rate by passing the coil at a relatively high speed through a furnace consisting of numerous sections.
Continuous Casting
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.
Continuous Sheet Galvanizing
A continuous process used to produce a zinc coating on steel sheet by immersion in a bath of molten zinc. Controlled wiping of the coating after galvanizing produces thin uniform coatings of zinc (with no alloy layers), usually 15 to 20 um (0.6 – 0.8 mils) thick. The coating is sufficiently ductile to withstand deep drawing or bending.
Continuous Variable Crown
Hydraulic system that supplies the force to all the cylinders associated with work-roll balance and bending and back-up roll balance (also supplies force for work roll shifting).
Continuous Weld Process (Fretz-Moon Process)
A process for making welded steel tubes in which a continuous strip is passed (by joining the ends of the coils) through a tunnel furnace, from which it emerges at welding temperature to enter a series of rolls which form it into a tube and weld the abutting edges together. The resulting continuous tube is cut to the desired length.
Contraction Cavity
A cavity formed in an ingot as a result of contraction during solidification. Also referred to as shrinkage cavity or pipe usually located in the hot-top region of killed steel.
Controlled Rolling
A hot rolling process in which the temperature of steel is closely controlled, particularly during the final rolling passes to produce a fine grain microstructure.
Conversion Cost
Resources spent to process material in a single stage, from one type to another. The costs of converting iron ore to hot metal or pickling hot-rolled coil can be isolated for analysis.
Converter/Processor
Demand from steel customers such as rerollers and tube makers, which process steel into a more finished state, such as pipe, tubing and cold-rolled strip, before selling it to end users. Such steel generally is not sold on contract, making the converter segment of the mills’ revenues more price sensitive than their supply contracts to the auto manufacturers.
Convertor
The pear shaped refractory lined (acid or basic) vessel in which the pneumatic steel making processes are carried-out. The vessel is mounted suitably for tilting for introducing the liquid material and taking out the blown material. The air, oxygen, carbon dioxide, steam or a mixture of these, is blown through a detachable bottom, side or top.
Coppered Wire
A wire produced by wet drawing with a copper sulphate or copper tin sulphate solutions for improving drawability. The colour depends upon the chemical used and the drawing operation imparts a luster to the wire resulting into improved appearance and limited corrosion resistance.
Core
Inside diameter of a coil.
Also
(1) In a ferrous alloy that has undergone case hardening, that portion of the alloy structure not part of case (see case). Typically considered to be the portion that (a) appears light when etched, (b) has an unaltered chemical composition or (c) has a hardness value lower than that of the case
(2) A specifically formed material inserted in a mould to shape the interior or other part of a casting that can not be shaped as easily by the pattern.
Core Loss
The quantity, expressed in watts per kilogram in SI and watts per pound in FPS system, can be defined as the electrical energy that is expended in the core steel without contributing to the work of the device. The two components of core loss are eddy current loss and hysteresis loss.
COREX®
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.
Corrective Leveling
Capability of a leveling machine to remove or reduce shape defects across the strip, coil, or sheet, in addition to flattening lengthwise curvatures. Generally employs 17 to 23 small diameter rolls with adjustable back ups for varying nest across face of machine.
Corrosion
The gradual degradation or alteration of steel caused by chemical or electrochemical attack due to atmosphere, moisture, or other agents.
Corrosion Fatigue
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.
Corrosion Resistance
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.
Corrosive Wear
Wear in which chemical or electrochemical reaction with the environment is significant.
Coupling Tubes (Coupler Tubes)
Tubes of suitable dimensions for the production of couplings.
Cracked Edges (Broken Corners)
Discontinuity or cracked condition on the edge (at right angles to the direction of rolling) of rolled products. The term ‘broken corners’ is used in connection with large sections, such as blooms, billets and slabs.
Cracking
A coating defect consisting of a break in the cured film which exposes the bare substrate. Cracking usually occurs during fabrication of the coated plate when the coating is too brittle or the adhesion is too low.
Cratering
A coating defect consisting of small, apparently uncoated, spots of coated plate consisting of a very thin film of coating which was contaminated by oil, silicone, or foreign matter. Eyeholing is similar to cratering, but with metal exposure in the crater.
Crawling
A coating defect consisting of a lack of adhesion to, or dewetting of, the substrate while the coating or ink is wet. The cause is due to a difference in surface tension of the coating and substrate. Crawling is also known as cissing and dewetting.
Crazing (Surface Crazing)
Markings on ingot or ingot mould surface in the form of a network, in a mosaic pattern giving the appearance of crocodile skin.
Creep
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.
Creep Recovery
The time-dependent decrease in strain in a solid, following the removal of force. Recovery is usually determined at constant temperature.
Crimped Edge
A damaged edge due to the strip wandering side-to-side into obstructions as it moves down the line.
Critical Cooling Rate
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.
Cropped Head / Tail
Squaring of the strips by use of mechanical shear.
Cropping
Shearing off discard from the ends of an ingot or bloom or forged products prior to further working. End discard shearing of semi-finished or finished products is also called cropping.
Crossbow
A curvature across the width of the strip at a 90o angle to the direction in which the strip has been rolled or uncoiled.
Cross Breaks
- Creases which appear as parallel lines transverse to the direction of rolling. 2. Quality defect on the edge of plate coming to the line (broken steel but not open breaks). 3. Hard spots caused by abrupt deformation of the strip after hot rolling and due to stressing beyond the elastic limit of the metal.
Cross Rolling
Rolling in the direction transverse to the longitudinal axis of the ingot or slab, as in the production of plate or sheet.
Crown
- The difference in thickness between the edge and center of the strip. 2. Thickened center of a strip of steel; can also have a crown on the work roll; two-point crown on a roll means a crown of 0.002 inches. 3. The crown, or center, refers to the tendency of a sheet to be heavier in gauge in the center than on the edges. It may be caused by the use of hollow, or worn back-up rolls, work rolls improperly ground, or excessive work in the last finishing stand.
Crucible Process
A steel making process in which the charge, generally small (roughly 20 to 25 kg), is melted in a crucible for the production of very high quality steel out of contact with fuel. The product, known as crucible steel, is used for making tool steels.
Crucible Steel
Steel made by the crucible process.
Cryogenic Steel
Steels, such as 9% nickel steel and the austenitic stainless steels, are capable of retaining toughness in applications involving the storing and handling of liquefied methane, oxygen, nitrogen, argon, hydrogen and helium to –273o.
Culvert Pipe
Heavy gauge, galvanized steel that is spiral-formed or riveted into corrugated pipe, which is used for highway drainage applications.
Cupping
An internal transverse crack in the wire which may result in fracture of the cup and cone type. It may be caused by excessive cold work or by segregation where the harder section is less ductile than the surface.
Cure Time
Full polymerization is a function of time and temperature.
Curing
The process by which synthetic materials form continuous films by various combinations of oxidation, solvent evaporation and heat of polymerization according to their basic resin structures.
Cut Edge
The normal edge that results from the shearing, slitting or trimming of a mill edge.
Cutoffs
A pair of blades either machined in the corner of dies or inserted in the dies, used to cut away forging from the bar.
Cut-to-Length
Process to uncoil sections of flat-rolled steel and cut them into a desired length. Product that is cut to length is normally shipped flat-stacked.
Cycle Annealing
An annealing process that uses a predetermined and closely controlled time temperature cycle to produce specific properties or microstructure.