Steel Dictionary

A

Aging (a.k.a. Age Hardening) A process by which hardness and strength of steel increases and  ductility decreases  over time. Special Killed (i.e., aluminium killed) prevents that condition.

AISI American Iron & Steel Institute.

Aluminized A cold-rolled sheet with aluminium applied (by hot-dip process) to the top and bottom sides. Provides excellent heat resistance and very good corrosion resistance.

Aluminium Improves ductility. Chemical symbol Al.

Aluminium Killed see Special Killed.

Annealing A process involving the controlled high-temperature heating and subsequent cooling of as-rolled (usually Full-Hard) Cold Rolled to induce softness and greater formability.

ASTM American Society for Testing and Materials. Organization which sets technical standards and specifications for steel and other materials, systems, services, etc. Generally, ASTM standards constitute the "laws" governing steel products.

 

B

Bake Hard enable Steel A grade of cold rolled sheet with good dent resistance, especially common in automobile doors and panels.

Band A basic form of hot rolled coil, without undergoing temper-levelling (skin passing). Bands are especially susceptible to wave, centre buckle, cross breaks and minor surface defects, often referred to as unprocessed coil.

Bend, Longitudinal A bend in the direction of (with) the grain; easier bend

Bend, Transverse A bend perpendicular to (against) the grain; harder bend

Bend Radius Inside radius of a bent section, normally indicated as a factor of material thickness (T).
1-T bend diameter = ½-T bend radius.

Bend Test Tests used to determine steel ductility in which material is bent (with or against the grain).

Black Plate A specific form of light gauge (typically under .016") cold rolled sheet, usually used as feedstock for Tinplate.

Blank A generally small steel sheet, typically with restrictive width, length and diagonal tolerances.

Bowdlerized Hot-dipped galvanized treated with phosphate-treated improved paint ability, corrosion resistance and formability as regular galvanized. A medium-dark grey surface with some spangle appearance.

Boron Can improve ductility and hardenability. Chemical symbol B.

Burr A thin ridge of roughness left by a cutting operation such as slitting, trimming, shearing, blanking, or sawing.

C

Camber The deviation of a coil or sheet's side edge from a straight line, the measurement taken on the concave side with a straight edge.

Carbon Main hardening element in steel. Usually, as carbon increases: tensile increases; ductility and weldability decline. Chemical symbol C.

Chemical/Chromate Treatment A chemical solution applied to galvanized to further forestall rust.

Chromium Hardens steel and prevents rust. Is prominent in stainless steel. Chemical symbol Cr.

Coating Weight The amount of zinc and/or aluminium applied to Galvanized, Electrogalvanized, or Aluminized sheet, normally expressed in oz./ft2.

Cold Rolling Passing of Hot Rolled coils through work rolls to reduce and tighten thickness range, improve shape, and surface quality.

Columbium Often used in high-strength low-alloy steels for increased yield and tensile strengths. Also referred to as Niobium. Chemical symbol Cb.

Commercial Steel (CS) Material with mechanical properties intended for simple bending (i.e., 180° flat) or moderate forming.

Copper Reduces atmospheric corrosion resistance. Chemical symbol Cu.

Corrosion (a.k.a. Rust) Degradation of metal caused by atmospheric conditions, i.e., moisture and/or oxygen.

Corrosion, Water Stain Superficial oxidation of the surface in the absence of circulating air. Often caused by moisture trapped between closely adjacent metal surfaces such as between wraps of a coil or sheets of a stack. On Hot Rolled and Cold Rolled products the color is typically yellow, orange and/or red. On Galvanized, it's often a whitish color but can also range to black.

Crown The contour on a sheet where the thickness increases from the edges to the centre.

Cut Edge More defined than mill edge, usually associated with tighter width tolerances.

D

Dead Soft Material that has not been rolled or tempered following annealing. Characterized by very low hardness, yield strength, tensile strength with comparatively high elongation.

Debur To remove sharp edges from a slit or cut edge.

Density The mass per unit volume of a substance. The density of carbon steel is .2833 pounds per cubic inch.

Drawing Steel For applications involving ductility beyond Commercial Steel.

Ductility The ability a sheet to allow change in shape without fracturing.

E

Edging The process of applying a particular shape (i.e., round, square) to a slit edge.

Elasticity The ability of steel to return to its native shape and dimensions.

Electrogalvanized A thin coating of zinc applied by electrolytic deposition to a cold rolled substrate. Electrogalvanized usually has less corrosion resistance than hot-dipped galvanized, but with very good paint ability.

Elongation A measurement of ductility/drawability. Expressed as the (%) increase of a given distance (usually 2") prior to fracture during tensile test.

Extra Smooth Galvanized Spangle-free for more uniform surface appearance and/or to improve paint ability.

F

Flatness Measurement of a sheet's conformance to a flat horizontal surface. Maximum variance from the surface (wave) is the extent to which the sheet is out-of-flat.

Forming Steel (FS) Softer than Commercial Steel, this category was previously known as Drawing Quality (DQ). It applies to coated sheet products, i.e., Galvanized, Galvannealed, Aluminized.

Fracture A break in steel, first observed at the surface.

Full Hard (FH) Steel rolled without subsequent annealing. Defined by a Rockwell higher than B84, with elevated yield and tensile strengths and very low elongation. Not suited for severe bending or drawing.

 

G

Galvalume Cold Rolled sheet with a coating of aluminium (55%) and zinc (43%). The coating is applied in a continuous hot-dip process (similar to galvanized). It offers outstanding rust resistance (typically, 3x that of Galvanized). Galvalume can be ordered to various coating weights.

Galvanized A cold rolled or hot rolled pickled substrate upon which zinc is applied to promote corrosion resistance. There is a direct correlation between the amount of zinc applied and the steel's rust protection. Zinc can be applied by either a hot-dipped or electrolytic deposit process.

Galvannealed A type of hot-dipped galvanized with an iron-alloy layer to enhance paint ability, has a medium-light grey, smooth appearance, offers corrosion protection similar to regular hot-dipped Galvanized.

Gauge A number representing steel's nominal thickness (within minimum and maximum tolerances).

H

Half Hard Referring to Cold Rolled with a Rockwell range of B70-85. Normally will only accept an approximate 90° bend on 1t diameter without fracture.

Hardness Resistance of steel to surface penetration. Usually referenced by a Rockwell hardness number, i.e., B60.

Heat The amount of steel produced from a production lot.

High Carbon steel with carbon content exceeding 0.50%.

High Strength Product intended for uses calling for higher strength levels, usually starting at 35,000# minimum yield strength.

High Strength Low Alloy Group of steels in which strength is achieved by the precise addition of alloying elements (i.e., Columbium, Vanadium, Molybdenum, Titanium).

 

I

ID The inside diameter of a coil.

Impact Testing Procedure to determine the resistance of steel to fracturing under extreme conditions.

Intermediate Temper Cold Rolled hardness referenced within a 15-point Rockwell range, i.e. Quarter Hard B60-75.

Interstitial Free (IF) Steel A relatively new form of sheet product with very high ductility for deep drawing, usually produced via vacuum-degassing and nitrogen. IF steel contains very low carbon (.008 max.), manganese .20 max., and titanium.

Iron A raw material of and the most prevalent element in carbon steel, representing about 99% of the chemical composition. Chemical symbol Fe.

I.S.M. Institute of Supply Management (formerly National Association of Purchasing Managers).

 

K

Killed Steel In conjunction with Drawing Steel, material is deoxidized (using Aluminium) to allow for uniform chemical composition and freedom from age hardening.

L

Lead Improves machinability of steel. Chemical symbol Pb.

Levelling Flattening of coil through series of rollers to reduce or eliminate distortions in thickness, shape and/or surface quality.

Light Matte Finish Cold rolled surface intended for a smoother painted or plated coating, usually has a profilometer range of 20-40 microinches.

Lock forming Quality (LFQ) Galvanized sheet ability to accept machine lock forming, usually a back-to-back 180° bend on 1t diameter, commonly used in ductwork. The LFQ designation has been replaced by Commercial Steel (CS).

Lock seam Test Procedure conducted on Galvanized to determine zinc adherence to the substrate.

Low Carbon steel with carbon content below 0.25%.

M

Manganese Contributes to hardness and strength, but less than carbon. Tends to minimize segregation, usually beneficial to surface quality. Chemical symbol Mn.

Martensite An ultra-high strength form of steel with tensile strengths ranging from 130000-215000 psi.

Matte Finish a specified Cold Rolled surface roughness (or brightness), measured with a profilometer.

Micrometre Instrument used to ascertain steel thickness.

Mechanical Properties Refers to structural characteristics, i.e., tensile strength, yield strength, hardness, and bend ability.

Mild Steel Usually refers to carbon steel with a Carbon of 0.15% maximum.

Mill Edge Standard edge used in Hot Rolled. Does not have a definite shape; has liberal width tolerances.

Minimum Spangle In hot-dipped Galvanized, refers to a relatively small flower like crystallization pattern.

Molybdenum Sometimes used in high-strength low-alloy grades for increased yield and tensile strengths. Chemical symbol Mo.

Motor Lamination/Electrical Sheet A type of Cold rolled sheet engineered for use as electromagnetic core material for electrical equipment (i.e., motors, transformers).

 

N

Niobium Commonly referred to as Columbium, often used in high-strength low-alloy steels for increased yield and tensile strengths. Chemical symbol Nb.

Nitrogen Tends to increase hardness, yield and tensile strengths, contributes to age hardening effects. Chemical symbol N.

O

OD The outside diameter of a coil.

Oiled Application of oil to surfaces to inhibit rust and reduce friction scratches possibly occurring during transit.

Olsen Test A method of measuring the ductility or drawing qualities of a sheet or strip.

Oxidation The exposure of steel to air (oxygen). Over time, it may result in stain, pitting and reduction in strength.

P

Phosphorous Reduces ductility and toughness, tends to segregate. Chemical symbol P.

Physical Qualities/Properties (aka Mechanical Qualities) Refers to values of tensile, yield, elongation, Rockwell, Erickson, Olson and/or other similar tests.

Pickling Removal of oxides and scale on hot rolled, through immersion in hydrochloric and/or sulfuric acids, usually accompanied by oiling to retard subsequent oxidation.

PIW Designates pounds per inch of width of a coil, determined by taking coil weight and dividing by width. For example, a 24000# coil at 24" wide is 1000 piw. The piw will also correlate to coil ID and OD measurements, the larger the piw, the larger the OD. Generally, larger coil PIWs are preferred since they require less production machinery setup time.

Profilometer Instrument measuring surface-roughness as an indicator of material brightness.

PSI Denotes pounds per square inch.

Pup Coil Generally a coil with less than 200 piw. (See PIW definition)

Q

Quarter Hard In Cold Rolled, hardness of B60-75, suitable for only limited bending and forming.

 

R

Regular Matte Finish The most common cold rolled surface with a uniform dull finish, usually suitable for painting. Profilometer range usually about 35-65 microinches.

Resquaring Process of blanking or shearing sheets to improve width, length, and diagonal measurements.

Rimmed Steel An older type of steel manufacture in which there were significant differences in chemical composition. Rimmed product generally exhibited good surface quality. Rimmed steel is no longer produced in the North American market.

Rockwell A test measurement to determine hardness. In low carbon steels, Rockwell can indicate approximate yield strength. To get yield strength, multiply Rockwell by 1000 and subtract total by 20000. For example, a B53 Rockwell will approximate a 33000 yield (53 x 1000 - 20000).

Roll forming Fabrication method in which steel (usually coil) is linearly, progressively deformed by passing through a consecutive series of rolls to produce a predetermined profile.

S

SAE Society of Automotive Engineers. Helps develops standards for auto-related steel products.

Salt Spray Test A procedure to determine the coating longevity of steel when exposed to corrosive effects of saltwater.

Scotch Brite A scratch pattern surface induced by brushing with textured rolls, can often reduce or eliminate light rust.

Sheet Flat-rolled steel generally less than .250" in thickness and wider than 12". The formula to calculate steel sheet weight is: thickness (in.) x width (in.) x length (in.) x density (.2833 lb./cubic inch).

Sidewall (SW) The contour of a coil's sides and edges. Ideally, they are free of damage, smooth and straight.

Silicon A deoxidizing element in steelmaking; very slight tendency to segregate; generally detrimental to surface quality. Chemical symbol Si.

Slab The primary steel shape from which coils are then rolled.

Slit Edge An edge produced from slitting; typically, tighter width tolerances than mill edge or cut edge.

Slitting The continuous cutting if a steel coil into narrower strip widths.

Spangle In hot-dipped galvanizing, the visual manifestation of zinc when it solidifies. Appearing like a snowflake, spangle can be controlled in size and brightness. Regular Spangle is typically 3/8"- 3/4". Minimum Spangle is approximately 1/8". Extra-Smooth has no spangle because of surface rolling after galvanizing. Zero spangle has no spangle, because of zinc pot chemistry.

Special Killed Steel with improve grain structure and prolong ductility through the addition of aluminium and/or silicon and the removal of oxygen and nitrogen.

Stainless Steel Strip steels with high chrome content to impede corrosion.

Stamping Metalworking operation involving the cutting and forming of steel using tooling and dies.

Strain The amount of elongation or compression when steel is subjected to a specific load.

Stress The force per unit area caused by externally produced forces.

Stretcher Levelled Flatness exceeding commercial tolerances, often specified for panels or similar applications.

Strip Steel flat-rolled steel produced to precise thickness and/or narrow width tolerances.

Structural Steel (SS) A steel quality specified when the minimum finished part strength (usually in load-bearing applications) is required, commonly specified in minimum yield strength (i.e., 33000 psi, 40000 psi, 50000 psi, or 80000 psi).

Sulfur A chemical element that tends to lower ductility and weldability; prone to foster segregation; impairs surface quality. Chemical symbol S.

T

T-Bend A mechanical procedure in which a steel sheet is bent 180° with the inside bend diameter expressed in terms of the material thickness. A bend of 1-T is equivalent to the material thickness; a 2-T bend equals twice the material thickness.

Tandem Mill A progressive series of rolling mill stations in which coils are cold worked, primarily to reduce thickness and improve flatness.

Temper Refers to steel hardness resulting from mechanical, chemical and/or thermal properties. Generally produced by cold-reduction, typical classifications are soft, quarter-hard, half-hard, three-quarter hard, and full hard.

Temper-Passed/Rolled A cold reduction of a sheet, passing through a series of rolls, to improve flatness and surface finish, usually reduces or eliminates cross breaks, centre buckle.

Tensile Strength The maximum strength that steel can withstand prior to fracture. Tensile testing measures maximum load ratio in relation to original cross-section area.

Tension Levelled Flat rolled product that has been passed through rollers which stretch the material beyond its yield point, producing improved flatness.

Tin Chemical symbol Sn.

Tin-Plate Very light gauge cold rolled with electrolytically-deposited tin on both sides, used for the manufacture of cans.

Titanium Often used in high-strength low-alloy steels for increased yield and tensile strengths. Also used in EDDS steels to increase ductility. Chemical symbol Ti.

Tolerance permissible variation in dimensions (thickness, width, length, diagonal).

Ton A unit of weight measurement. A net ton is 2,000 pounds. A metric ton is 2,204.6 pounds. A gross (or long) ton is 2,240 pounds.

Transverse Perpendicular to the direction of rolling.

Traverse Winding a.k.a. oscillate, coils that are wound like a fishing reel (in contrast to ribbon winding).

Triple Spot Test A process for measuring the coating weights, representing the average weight from three samples taken across a coil/sheet width.

 

U

Ultimate Strength See tensile strength.

V

Vacuum Degassing An advanced steelmaking process that removes oxygen and nitrogen. It is used to produce very pure ultra-low carbon steels with high drawing and formability features, especially for automotive body applications.

Vanadium Often used in high-strength low-alloy steels for increased yield and tensile strengths. Chemical symbol V.

Vitreous Enamelling Iron A type of cold rolled sheet produced for porcelain enamelling, has very low carbon levels and a rough matte finish (typically 55+ microinches).

W

Weld A joining or union of steel, created by the application of very high temperatures.

Weldability The adaptability of steel to welding, typically influenced by chemical composition, surface finish, coating type and weight.

Work Hardening The increase in resistance to deformation as a result of cold working, i.e., rolling, roll forming.

 

Y

Yield The amount of net finished product generated in relation to the initial gross amount. (Not to be confused with Yield Point.)

Yield Point The load or stress at which a marked increase in deformation (i.e., elongation or discontinuous thickness reduction) occurs without increasing the applied load.

Yield Point Elongation (YPE) Refers to a non-uniform elongation of steel and resulting susceptibility to Lüders bands (surface strain lines, resembling cross breaks). The deformation can be measured and while there is no accepted industry standard, generally a YPE measurement below 0.5% would suggest an absence of strain lines during/after stamping.

Yield Strength The stress at which steel exhibits a specified deviation from a linear proportionality between load and elongation. For steel (and many other metals) an offset of 0.2% is the reference point. If steel is sufficiently stretched, the length is increased. The measurement points at which the length permanently increases by 0.2% represents the yield strength. For example, if a load is applied upon a steel sample, any 1.000" of its length becomes 1.002" after loading to the yield strength. Yield strength is lower than tensile strength, since the steel will "give" before it fractures.

Z

Zinc A chemical element applied (either hot-dipped or electrolytically) to steel to improve corrosion resistance. There is a direct correlation between the zinc coating weight and rate of atmospheric corrosion, the more the zinc, the slower the corrosion. Chemical symbol Zn