Glossary & Terms
- Coatings Designates Zinc–Iron Alloy (Galvannealed) Coating, either thermally treated (galvannealed) or electrolytically applied.
- American Association of State Highway and Transportation.
- A process in which steel increases hardness and strength, and ordinarily decreases ductility over time. Special Killed (i.e. aluminum killed) prevents that condition.
- Changes in physical and mechanical properties that occur when low–carbon steel is stored for some time. Aging is also accelerated by exposure of steel to elevated temperatures. Stretcher strains and fluting can result from aging.
- American Iron & Steel Institute. No longer writes chemical specifications. The SAE has taken over the task.
- When a metallic coating, through heat–treating, becomes a part of the base metal. i.e. galvannealed, aluminum zinc, long ternes.
- A Cold Rolled sheet with aluminum applied (by hot–dip process) to the top and bottom sides. Provides excellent heat resistance and very good corrosion resistance.
- Deoxidizes the steel and ties up Nitrogen. This combined action improves ductility. Chemical symbol Al.
Aluminum Coated Steel Sheets
- Type 1: a carbon steel product continuously hot–dipped coated with an aluminum coating containing 5 to 10% silicon. Heat resistant grade used for heat exchangers and automotive mufflers. Type 2: a carbon steel product continuously hot–dipped coated with pure aluminum. Combines the strength of the steel substrate and the corrosion resistance and reflectivity of the pure aluminum.
- see special killed.
Aluminum Zinc Alloy Coated Steel Sheets (Galvalume)
- A carbon steel product continuously hot–dipped coated, nominally by weight, with 55% aluminum, 1.6% silicon and the balance Zinc. The product is intended for applications requiring corrosion resistance, heat resistance or both.
- A process of controlled heating, soaking at elevated temperatures and controlled cooling for the purposes of softening, developing a grain structure, improve machinability or obtaining a special set of physical or mechanical properties.
- American Society for Testing and Materials. An organization which sets technical standards and specifications for steel and other materials, systems, services, etc. Generally, ASTM standards constitute the "laws" governing steel products.
Bake Hardenable Steel
- A grade of Cold Rolled sheet with good dent resistance, especially common in automobile doors and panels.
- A basic form of Hot Rolled coil, as rolled from the hot strip mill. Usually has a 28" to 30" ID, a rolled curved head (ID) and an irregular fish tail (OD).
- A bend in the direction of (with) the grain; easier bend.
- A bend perpendicular to (against) the grain; harder bend.
- Inside radius of a bent section, normally indicated as a factor of material thickness (T). 1–T bend diameter = 1/2–T bend radius.
- Test used to determine steel ductility in which material is bent (with or against the grain).
- A hot–worked, semi–finished product suitable for subsequent working by such methods as rolling, forging, extruding, etc.
- 1: The uncoated steel sheet product before electrotinning. An AISI flat rolled carbon steel product classification for a Cold Rolled coil or cut length product ranging in width from over 12" to less than 32" and 29 gauge (.0135") or lighter. 2: A specific form of light gauge (typically under .016") Cold Rolled sheet, usually used as feedstock for Tinplate.
- A generally small steel sheet, typically with restrictive width, length and diagonal tolerances.
- In coated products, a defect caused by the formation of gas bubbles in a zinc or aluminum coating. In uncoated, refers to a raised spot on the steel surface evidencing inclusions and small laminations.
- 1: A proprietary name for a phosphate treated steel or metallic coated substrate. See Phosphatized. 2: Hot–dipped galvanized that has been phosphate–treated for improved paintability. Same corrosion resistance and formability as regular galvanized. A medium–dark gray surface with some spangle appearance.
- Improves ductility by combining with nitrogen. Increases hardenability by slowing down the transformation rate. Chemical symbol B.
- Curvature in the plane of sheet or plate in the rolling direction. Usually caused by unbalanced stresses between the top and bottom surfaces of the rolled product – Coil set.
- Curvature across the rolling direction of sheet. A more severe case can result in a center buckle. Usually caused by unbalanced roll bending during the hot rolling – Canoe shape.
- Annealing steel by heating in a sealed container under conditions that minimize oxidization.
- A distortion (usually repetitive) in flatness during rolling.
Buckle, Arbor Bends
- Creases, wrinkles or departures from flat, occurring perpendicular to the slit edge of a coil, which are repetitive in nature, with severity decreasing as the distance increases in the coil from the original source. Often they are found at/near the coil ID or OD.
- Undulations (wavy regions) in the center of the metal.
- Undulations (wavy regions) along the edge(s) of the metal.
- A coil made by welding (or stitching) together two or more coils to make a larger one, often for efficiency during the galvanizing process.
- A thin ridge of roughness left by a cutting operation such as slitting, trimming, shearing, blanking or sawing.
- A thin turned down edge on the sheet as a result of shearing or slitting. Only the Perforating Association has a suggested 10% of metal thickness as a listed maximum tolerance.
- The deviation of a side edge from a straight line with the measurement (per unit length) being taken on the concave side with a straight edge.
Capped Steel (OLD STEEL MAKING)
- Capped Steels have characteristics similar to those of rimmed steels but to an intermediate degree between those of rimmed and semi–killed steels. Capped steels are not as segregated and are harder than rimmed steels. Because of the increased hardness of a sheet produced from mechanically capped steel, this type is not generally used where severe forming is involved. However, this grade is satisfactory for most applications where only mild forming or bending is required. Generally, steels of this type are above, 0.15% carbon and are applied to sheet, strip, skelp and tin plate.
- Main hardening element in steel. Usually, as carbon increases: tensile increases; ductility and weldability decreases. Chemical symbol C.
- Steel which owes its properties chiefly to carbon without substantial amounts of other alloying elements; also known as straight–carbon steel or plain–carbon steel. Steel is classified as carbon steel when the maximum content does not exceed the following percentages: Manganese: 1.65; Silicon: 0.60; Copper: 0.60 (when specified).
- A wave condition in the coil/sheet, caused by the center (in the rolling direction) being longer than the edges.
- A chemical solution applied to galvanized to further forestall rust.
- Process for passivizing a galvanized coating to retard the formation of "wet storage stains" during shipment and storage. Most chemical treatment is used to prevent storage stains. Process for preparing a surface for painting. See Phosphatized.
- Hardens steel and prevents rust. Is prominent in Stainless steel. Chemical symbol Cr.
Coating, High or Low
- Failure to meet the proper coating weight range.
- A coating thickness greater than nominal due to uneven application.
- 'G' free Zinc, 'A' Zinc–Iron alloy (Galvannealed), 'X' no coating. i.e.. one side coated (Metric), 'E' exposed part (Metric), or 'U' unexposed part grams/m3 (Metric)
- A non–uniform extraneous deposit of coating on the coated sheet.
- On coated steels, a hump in the rolling direction usually caused by improper wiping when exiting the coating tank.
- The amount of zinc and/or aluminum applied to Galvanized, Electrogalvanize, or Aluminized sheet, normally expressed in oz./ft2.
- A deficit, exhibiting creases, a snaky pattern across a metal sheet running transverse to the coiling or rolling direction. The spacing is irregular and its location in the surface is very often random. Creases of ridges, which appear as parallel lines, transverse to the direction of rolling. They generally extend across the width of the sheet.
Coil Coated Sheet Steel
- A sheet steel product exhibiting paint, plastic, or non–metallic film on one or both of its surfaces.
- Longitudinal bow in an unwound coil, caused by the action of winding the sheet into a coil. Also termed pre–painted.
- A coil weld is a joint between two lengths of metal within a coil. They are not always visible in a cold reduced product.
Cold Rolled Products
- Flat rolled products for which the approximate required thickness has been obtained by rolling HR bands without heating at approximately room temperature.
Cold Rolled Sheet Steel
- A flat–rolled steel product classification produced to an ordered thickness by cold reducing a heavier gauge Hot Rolled coil. The cold–reduced coil (full hard) is subject to additional processing. The coil could be run through a continuous coating line; or softened in a controlled anneal and temper rolled.
- Passing of Hot Rolled coils through work rolls to reduce and tighten thickness range, improve shape and surface quality.
- An out–of–round condition of coil often due to inappropriate tension during rewinding operations. The internal diameter (ID) is compressed.
- Often used in high–strength low–alloy steels for increased yield and tensile strengths. Also referred to as Niobium. Chemical symbol Cb.
Commercial Quality (CQ now CS)
- A sheet of this quality is for uses involving simple bending or moderate drawing. A commercial quality sheet can be bent flat upon itself in any direction at room temperature. Sheets of this quality can be specified to ASTM A526 now ASTM A1008 (full hard) is subject to additional processing, continuous line, controlled annealing and temper rolling to produce un–coated Cold Rolled sheet steel products.
Con Cast Steel
- There is a large–scale production of continuous cast slabs, steels of this type have been found to be equal to and often better than conventional cast steels of the same nominal grade. One of the biggest metallurgical advantages is the uniformity of chemical composition and mechanical properties as compared to ingot cast steels. This results from the fact that the continuous cast slab solidifies in a few minutes, whereas in an ingot, complete solidification is not obtained until hours have gone by. Chemical segregation, characteristic of ingot cast steel, is virtually absent in continuous cast slabs.
- The heat treating process performed in a line designed to unwind a steel coil, pass it through a controlled atmosphere furnace in a single thickness, cool it at a controlled rate, and rewind it for shipment to its next destination.
Continuously Cast Steel
- A process involving the pouring of liquid steel continuously as it solidifies into a desired shape, square, rectangular, or other cross section. The shape is withdrawn from the mold according to a calculated rate based upon the cross section being cast, the metered rate of the liquid metal, the available cooling and other factors.
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.
- A process in which steel coils are unwound and passed through a furnace where they are subjected to a prescribed annealing cycle under a protective atmosphere.
- Increases atmospheric corrosion resistance. Chemical symbol Cu.
Corrosion (a.k.a. Rust)
- Degradation of metal caused by atmospheric conditions, i.e., moisture, oxygen, chemicals. There are varying degrees of severity, i.e., extent across surface, depth of penetration into surface.
- Tears or discontinuity on the coil/sheet edge.
- A sharp deviation from flat in the sheet, which is transferred from processing equipment subsequent to the roll bite. If longitudinal, typical sources include idler rolls, leveler rolls, segmented rolls and slitter spacers. If transverse, typical sources include mandrels, coil ends and racks.
- A curvature across the width of the strip perpendicular to the rolling or coiling direction.
- Refer to Coil Breaks.
- The contour on a sheet where the thickness increases from the edges to the center.
- More defined than mill edge, usually associated with tighter width tolerances.
- Material that has not been rolled or tempered following annealing. Characterized by very low hardness, yield strength and tensile strength with comparatively high elongation.
- To remove sharp edges from a slit or cut edge.
- A press forming process utilizing the plastic flow characteristics of a metal to form deep cup or pan shapes with deeply recessed turns or comers.
Deep Drawing Special Killed Fully Stabilized (DDQSK IF)
- Explanation same as Extra Deep Drawing. Produced from vacuum degassed steel to eliminate coil breaks, strain lines and fluting during fabrication.
- Instead of exhibiting the same coating weight, or designation, per side of the sheet, this product will have contrastingly different coating weights on each side, i.e. one side will have a light coating and the other side will have a heavy coating.
- The mass per unit volume of a substance. The density of carbon steel is .2833 pounds per cubic inch.
- A sharply defined surface impression on the metal, which may be caused by a blow from another object.
- Foreign debris embedded in or under the coating from rolling or post–rolling operations.
Drawing Quality (DQ DS)
- 1: An ASTM designation for uncoated or metallic–coated sheet steel intended for a specifically identified part where the draw or deformation is moderately severe. The steel manufacturer selects the steel grade, chemistry and the processing to make the identified part. 2: As compared with sheet of Commercial Quality, Drawing Quality sheet has a greater degree of ductility and is more consistent in performance.
Drawing Quality Aluminum Killed (DQAK)
- Specially killed steel using aluminum as the deoxidizing agent.
Drawing Quality Special Killed (DQSK DDS)
- When Drawing Quality will not provide a sufficient degree of ductility for fabrication of parts or applications require that the sheet be free from aging, Drawing Quality Special Killed steel should be used. This quality is made by special steel making and processing practices. Also sometimes known as Deep Drawing quality.
Drawing Steel (DS)
- For applications involving ductility beyond Commercial Steel (CS).
- Drops of sediment atop galvanized sheet.
- The ability to permit change of shape without fracture. In steel, ductility is usually measured by elongation and reduction of area as determined in a tensile, hardness, or Olsen test.
- An A.S.T.M. designation for Exposed (parts)
- The outer boundaries of a sheet product. If untrimmed, termed Mill Edge, the rolling process squeezes the area and causes the edges to form a semi–cylindrical, slightly ragged, profile. As it runs parallel with the rolling direction, it deviates from a true straight line causing some slight variations in strip width. The ragged nature of a mill edge product varies from a fine, finishing file rasp appearance, to a very jagged sawtooth appearing, condition. Micrometer readings along a narrow band along the edge of the strip may indicate slightly less gauge thickness than that of the rest of the strip. This condition is termed "feathering";. When blanking or shearing parts from mill edge material, sufficient width allowance should be made to insure obtaining the shape and size of the pattern sheet. If trimmed, termed Cut Edge, the edge will resemble the result of shearing, slitting, or trimming the mill edge. The overall width from one end of the coil to the other will be uniform. If the product has been silt in a pickle line, the edge may exhibit some slight jaggedness, but no severe sawtooth appearing, condition.
- Excessive buildup of material on edge(s) during a rewinding operation. Typical causes include excessive edge burr, turned edge, and "dog bone"; shaped cross sectional profiles.
- Edge(s) with a crossbreak surface defect.
- Similar to center buckle but occurring along one or both edges.
- A heavier coating (zinc, aluminum) concentration at the edge(s) rather than the center of the coil.
- Severe bending (like a washboard) along a coil/sheet edge caused by improper rolling practice. Usually will occur in a belled edge shape.
- Sheet/coil edge that has been bent, torn or scraped by an object.
- A condition in the band of steel where the edges (in the direction of rolling) are longer than the center.
- The process of applying a particular shape (i.e., round, square) to a slit edge.
- Normal edge produced in hot rolling that does not conform to any definite contour. Mill edge product may contain some edge imperfections the more common types of which are, checked edges, thin edges (feather) and damaged edges due to handling or processing. These edge conditions are detrimental where joining of the mill edges by welding is practiced. When the customer intends to shear or blank, a sufficient width allowance should be made by the purchaser to assure obtaining the desired shape and size of the pattern sheet. A cut edge is the normal edge, which results from the shearing, slitting or trimming of a mill edge. Cold Rolled products are customarily furnished with cut edge. The edge cut is usually made in the continuous pickling operation prior to the cold reduction process.
- The ability of steel to return to its native shape and dimensions.
- Carbon Sheet Steels are widely used for electrical and magnetic applications. They are usually furnished as one of the following: Cold Rolled Lamination Steel: Type 1 is ordinarily furnished to a controlled chemical composition, usually carbon, manganese and phosphorous and it is provided in the full–hard or annealed condition. The annealed product customarily receives a light temper pass to enhance flatness and punchability. Depending upon the application, the purchaser may choose to anneal the stamped laminations to achieve better magnetic properties. Magnetic properties are not normally guaranteed by the steel producer. Cold Rolled Lamination Steel Type 2 is a specialty product available in the annealed condition with magnetic properties superior to Type 1. The improved magnetic properties are attained by special mill processing and controlled chemical composition, usually carbon, manganese and phosphorus. In the last stage of mill processing, special emphasis may be placed on obtaining high extensions during temper rolling. To obtain optimum magnetic properties, it is necessary that the consumer anneal to adequately decarburize and promote grain growth. Applications include motors, generators, ballast transformers. Available in coils and cut lengths.
- 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 paintability.
- 1: An ionic conductor. 2: A liquid bath, most commonly a solution of chemical salt or salts, that will conduct an electric current.
Electrolytic Tin Coated Sheet Steel
- Steel plated with tin using an electric current through an electrolyte.
Electrolytic Zinc Coated Sheet
- Proper name for Electrogalvanized.
Electrolytic Zinc Iron
- Steel plated with 10% to 20% iron and zinc, using an electric current to achieve a "layering"; of Zinc Iron produced in the Galvannealed Process.
- The amount of extension a test specimen undergoes to fracture during tensile testing. A measurement compares a before and after unit gauge length indexed into the specimen. The change is expressed numerically as a percentage of the original gauge length.
- Refer to Extra Smooth.
Extra Deep Drawing Special Killed
- A new variation of DQSK with very low carbon content to enhance deep drawing characteristics. Basically for automotive applications.
Extra Smooth Galvanized
- Extra–smooth finish is imparted to galvanized sheet by temper rolling after coating to obliterate the spangle in the zinc coating. Most extra–smooth galvanized sheet is intended for painted sheet applications.
- A condition in coated sheet where portions of the coating become loosened due to inadequate adhesion.
- The degree of surface smoothness, expressed as peaks per inch, or micro–inches of a temper rolled or skin passed steel strip. Includes surface reflectivity, brightness and dullness.
- Flatness is a measure of a cut length sheet's ability to conform to a flat horizontal surface. Maximum deviation from that surface is the degree to which the sheet is out of flat.
- Lines or ridges, which are diagonally transverse to the direction of rolling and generally confined to the section midway between the edges of a coil as rolled. They are somewhat irregular and tend toward a flat arc shape.
- Fluting is a series of sharp parallel kinks or creases occurring in the arc when sheet steel is formed cylindrically, as to stretch the outer surface well beyond its yield point.
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.
- A break in steel, first observed at the surface.
- A series of relatively short scratches variable in form and severity.
- A series of short abrasions caused by the rubbing of laps or sheets. Also called galling. Scratches are shallow; gouges are deep.
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.
- As a coating designator designates Free Zinc.
- Steel coated (by hot–dip method) with a molten alloy that Is 95% zinc, 5% aluminum–mischmetal.
- Friction scratches.
- Cold Rolled sheet with a coating of aluminum (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). It can be ordered to various coating weights.
- A term long used to describe steel sheet coated with zinc to promote corrosion resistance. The term is associated with the hot–dip process but the zinc coating can also be applied by electroplating. The hot–dip process consists of passing the steel through a bath of molten zinc. (See Hot–dipped Steel.) The electroplating process consists of the application of zinc by electrolytic deposition.
- A galvanized sheet steel, which is altered by heat treatments or other processes immediately after coating, before the zinc solidifies. The coating produced consists entirely of iron zinc alloy and has a rougher appearance than the surface of regular coating. This is known as 'galvannealed' steel. Sheets produced in this manner are dull gray in color, have no spangle, and after proper preparation, is well suited for painting.
- A number representing steel's nominal thickness (within minimum and maximum tolerances).
- Ghost lines are lineal irregularities in the surface which develop in drawing. They are parallel to the direction of rolling.
- An instrument used to compare the reflectivity of finishes.
- A deep scratch.
- Referring to Cold Rolled with a Rockwell range of B70–85. Normally will only accept an approximate 90–degree bend on 1T diameter without fracture.
Hardness, Hardness Tests
- Hardness is the resistance of a material to deformation, particularly permanent deformation, indentation or scratching. There is no absolute scale for hardness; therefore, to express hardness quantitatively, each type of test has its own scale of arbitrarily defined hardness. For sheet steel the primary method used is the Rockwell hardness test. Usually referenced by a Rockwell hardness number, i.e., B60.
Healed Over Scratch
- A scratch that occurred in a mill operation and was partially masked in subsequent rolling. It might open up during forming.
- The amount of steel produced from a production lot.
- Usually referring to Hot Rolled, a hump in the rolling direction usually resulting from a trapped center buckle after cold reduction.
- Excessive amount of coating (i.e., zinc or aluminum) applied to the surface.
- Steel with carbon content exceeding 0.50%.
- 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).
High Strength Steel
- 1: A specific class of low–alloy steels in which increased mechanical properties and, usually, good resistance to atmospheric corrosion are obtained with moderate amounts of one or more alloying elements other than carbon. Preferably called high–strength, low–alloy steels. 2: Commonly known as High–Strength Low–Alloy (HSLA), a specific class of low alloy steels in which increased mechanical properties, and usually good resistance to atmospheric corrosion, are obtained with moderate amounts of one or more alloying elements other than carbon. Galvanized flat steel sheets (HSLA) are coated with zinc by the continuous hot–dip process. You can also achieve high strength through physical, not chemical, properties.
- A metal void, usually caused by a non–metallic inclusion during rolling.
Hot Dip Steel
- This product is a steel sheet with a zinc coating that is applied by passing the steel through a bath of molten zinc in a continuous operation. The zinc enhances the corrosion resistance of the steel sheet. The product is available with various thicknesses of zinc coating. The coating thickness (weight) should be chosen carefully, with attention to the type of environment in which the sheet is expected to serve. In general, the corrosion resistance of the coating is directly proportional to the coating thickness.
- The inside diameter of a coil.
- Procedure to determine the resistance of steel to fracturing under extreme conditions.
- Particles of foreign material (i.e., oxides, silicates, sulfides) in steel, usually compromising physical integrity. These particles of non–metallic material usually oxides, sulfides, silicates and such are entrapped mechanically or are formed during solidification or by subsequent reaction within the solid metal.
- 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.
- A metallic element. However, In the steel Industry, Iron represents the product of a blast furnace containing 92% to 94% Iron. Blast furnace iron is also called pig iron or hot metal. Chemical symbol Fe.
Iron Zinc Coating
- (See Galvannealed and electro Zinc–iron).
- Institute of Supply Management (formerly National Association of Purchasing Managers).
- Just in time delivery.
- 1: Steel deoxidized by silicon or aluminum to reduce the oxygen content to a minimum so that no reaction occurs during solidification of the metal. Kilted Steels have more uniform properties and chemical composition than other types. 2: In conjunction with Drawing Steel, material is deoxidized (using Aluminum) to allow for uniform chemical composition and freedom from age hardening.
- An abrupt bend or deviation from flat, which is caused by localized bending during handling.
Lamination (a.k.a. Segregation or Piping)
- Defect caused by the presence of internal blisters, seams or inclusions. Harmful to structural integrity; could cause steel fracturing.
- Imperfections resulting from the presence of blisters, seams or foreign inclusions, and sometimes visible on the surface of the metal.
- Coil ends are "lapped" over one another and welded or stitched for production purposes. As a result, the thickness of the steel is doubled at the weld area.
- Improves machinability of steel. Chemical symbol Pb.
- Flattening of coil through series of rollers to reduce or eliminate distortions in thickness, shape and/or surface quality.
- Abbreviation for Lock Forming Quality.
Light Matte Finish
- Cold Rolled surface intended for a smoother painted or plated coating. Usually has a profilometer range of 20–40 micro inches.
- Referring to coated steels, an area of a coil where the coating line was halted. This region is usually characterized by irregular and questionable coating integrity.
Lock Forming Quality (LFQ)
- This quality should be specified when sheet is subject to machine lock forming for end uses such as heating and air conditioning ductwork. Lock Forming Quality sheet will be furnished to ASTM A–527 when specified.
- Procedure conducted on Galvanized to determine zinc adherence to the substrate.
Long Terne Sheet
- Is produced by passing the steel through a molten bath of terne metal (lead and tin alloy) in a continuous coating operation. The terne coating provides the steel sheet with a number of enhancements for a variety of applications. It provides good corrosion resistance for fuel tank applications. The terne coating is very ductile and acts as a lubricant for parts that involve deep drawing. The coating provides a surface that is readily solderable for electronic–component chassis applications. Also, the terne coating (without the passivation treatment) is paintable without any special surface preparation.
- A coil that is not wound tight due to insufficient tension when winding.
- Steel with carbon content below 0.25%.
- Abbreviation for long ternes.
- Slipperiness. The ability of steel sheet to slide in a forming die.
- Elongated surface markings or depressions appearing in patterns caused by localized plastic deformation that results from a discontinuous yield and resulting yield point elongation.
- Contributes to hardness and strength, but less than carbon. Tends to minimize segregation. Usually beneficial to surface quality. Chemical symbol Mn.
- Surface damage at/near coil ID caused by roughened, damaged or non–circular arbor.
- Lines which are generally perpendicular to the rolling direction, caused by the leading end of the metal entering the leveling rolls resulting in minor surface disruptions. These disruptions then transfer to the surface of the rolled metal in subsequent rotations.
Mark, Chatter (Roll or Leveler)
- Close, intermittent lines transverse to the rolling direction.
- Appearance of surface where actual inclusion or the void it left is observed.
- A continuous scratch (which may also be creased) near a slit edge, caused by sheet contacting the slitter knife.
- A small repeating raised or depressed area on rolled products caused by the opposite condition on a roll. The repeat distance is a function of the offending roll diameter.
Mark, Roll Bruise
- A greatly enlarged roll mark whose height or depth is very shallow.
Mark, Roll Skid
- Scratch like, repeating patterns perpendicular to rolling direction. Usually caused by work roll misalignment.
- A large number of very fine scratches or abrasions. A rub mark can occur by metal–to–metal contact, movement in handling and movement in transit.
- Surface abrasions generally diagonal to rolling direction. Typically caused by fluttering of coil between leveling rolls.
- An ultra–high strength form of steel with tensile strengths ranging from 130000–215000 psi.
- A specified Cold Rolled surface roughness (or brightness), measured with a profilometer.
- Those properties of a material that are associated with the elastic reaction when force is applied, or that involve the relationship between stress and strain; for example modulus of elasticity or endurance limit. These properties are often incorrectly referred to as physical properties. Refers to structural characteristics, i.e. tensile strength, yield strength, hardness and bend ability.
- Instrument used to ascertain steel thickness.
- Usually refers to carbon steel with a Carbon of 0.15% maximum.
- Standard edge used in Hot Rolled. Does not have a definite shape; has liberal width tolerances.
- In hot–dipped Galvanized, refers to a relatively small flower like crystallization pattern.
- A mixture of rare earths. Cerium (0.04% and Lanthanum (0.04%). In aluminum–zinc alloy steel. Type 1 contains the two rare earth elements. Trade name: Galfan.
- A fully coated coil whose surfaces contain more than one coating, i.e. both regular galvanized (bright) and galvannealed (dull).
- 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).
- A narrowing of coil width caused by improper tension in rolls during production.
- Commonly referred to as Columbium. Often used in high–strength low–alloy steels for increased yield and tensile strengths. Chemical symbol Nb.
- Tends to increase hardness, yield and tensile strengths. Contributes to age hardening effects. Chemical symbol N.
- The outside diameter of a coil.
- Thickness deviation from the ordered specification and/or tolerances.
- A tight wave or undulation, also referred to as a trapped center buckle.
- Application of a suitable oil to flat–rolled steel to retard rusting. When surface is a consideration, it is also desirable in reducing friction scratches that may develop in transit. The oil coating is not intended to serve as a lubricant for subsequent fabrication.
- The practice of applying the protective oil, encompassing its formulation and the amount used.
- This is a cupping test made on an Olsen machine, used as an aid in determining ductility and deep drawing properties. The test simulates a deep drawing operation. It is continued until the cup formed from the steel sample fractures. Ductility and drawing properties are judged by the depth of the cup, position of the break, condition of the surface after the break, etc.
Orange Peel Strain
- The course grain condition, which occurs when large grains in the metal are present and become evident during drawing.
- Uneven wrap in coiling and lateral travel during winding. Improper alignment of rolls over which the metal passes before rewinding and insufficient rewind tension are typical causes.
- The difference between two diagonal measurements of a square, rectangular, square sheet or blank; also the deviation from 90 degree angles at the corners between the sides and ends of a rectangular or square sheet or blank.
- Excessively–prolonged exposure to pickling acids, usually resulting in a burnt or stained surface.
- Width exceeding the ordered dimension.
- Rust and corrosion. The exposure of steel to air (oxygen). Over time, it may result in stain, pitting and reduction in strength.
- See Phosphatized.
- Relatively invisible as applied to a galvanized sheet, this thin chemical film is applied to the surface of the coated sheet to minimize the tendency to "white rust"; (humid storage stain) during transit and storage. It is more effective than oil in preventing white rust. The product may be ordered without a passivation treatment to accommodate certain post–painting operations.
- See Embossed or Embossing.
- On galvanized, aluminized and other metallic–coated steels, the separation of the coating from the steel substrate.
- Refers to a surface treatment applied by the mill to provide a paintable surface. The treatment is a visible phosphate film (dull surface). It provides a surface that is readily paintable and enhances the paint adherence characteristics (sometimes referred to as bonderizlng).
- Reduces ductility and toughness; tends to segregate. Chemical symbol P.
- The properties, other than mechanical, that pertain to the physics of a material. For example, density, electrical conductivity, heat conductivity, thermal expansion.
Physical Quality (PQ)
- Also known as Structural Quality (SQ). There are applications where strength in the finished part is closely related to the strength of the steel sheet as ordered. For these end uses, physical quality should be specified. Sheets of this quality can be specified to ASTM A653 (old ASTM A–446).
- An area of heavy scale that has not been removed after pickling or other processing.
Pickle Stain or Burn Surface
- Discoloration due to excessive acid solution and/or steel's exposure to the same.
- Removal of mill scale or oxide by immersion of steel in a dilute solution off sulphuric or hydrochloric acid, then rinsed and dried.
- Transfer of portions of the coating from one surface of the sheet to an adjacent surface due to poor coating adhesion. Usually defined as <l% total coating loss or
- Small particles of debris trapped in the rolls and transferred to the sheet surface. Could apply to Cold Rolled or coated sheet.
- Fern–like ripples or creases usually diagonal to the rolling direction.
- A coating defect consisting of random, small round holes. The open area (pinhole) exposes the steel substrate. Usually caused by laminations, inclusions, scratches or improper lubricant.
- Similar to lamination, a void in the steel's thickness.
- A separation midway between the surfaces containing oxide inclusions.
- Random small depressions in the coating. Similar to pinholes, except that pitting does not reveal the bare substrate.
- A severe form of oxidation causing sharp depressions in the steel surface.
- 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 the 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.
- Two finishes suitable for most plating applications: commercial bright rolled with ground and polished rolls, has a relatively bright finish. Extra Light Matte produced with lightly blasted rolls, has a slightly duller finish than commercial bright. Base metal conforms to ASTM A653 (old ASTMA–366).
Porcelain Enameling Sheets (Vitrename)
- Sheet steel for porcelain enameling is chemically constituted and suitably processed to adapt it to the fabricating and enameling requirements of articles for vitreous coating under proper conditions. This product is generally produced in two types. Type I has an extremely low–carbon level commonly produced by decarburizing in an open coil process. In which the coil laps are separated for easy flow of annealing gases. When specified by the purchaser, this material is suitable for direct cover coat and enameling applications. This material is also suitable for ground and cover coat enameling practice. It has good sag resistance and good formability. Type II has moderately low carbon and manganese levels as produced in the melting operation. This material is suitable for ground and cover coat applications. The selection of chemical composition for Type II can be varied to provide either maximum resistance to sag or good formability. Sheet steel for porcelain enameling can be produced to stretcher level standard of flatness, re–squared or sheared into circles or sketches. Type III is a titanium stabilized ultra–low carbon product.
- A problem in which galvannealed's iron–zinc coating dislodges from the steel substrate.
- Coating applied to enhance formability.
Preprinted Sheet Steel
- Another name for cool coated steel sheet.
- An instrument that measures surface–roughness height in micro inches. The height is measured as the absolute deviation from a mean surface.
- Denotes pounds per square inch.
- A coil with relatively small PIW, typically under 200. They often contain defects, i.e. dents, dings and scratches.
- Refers to the suitability of the steel for the purpose or purposes for which it is intended (see commercial quality, drawing quality, structural quality).
- In Cold Rolled, hardness of B60–75. Suitable for only limited bending and forming.
- Sheet edges that are cracked, torn, ragged, split and/or otherwise damaged.
- Reducing the thickness of a sheet or strip by hot or cold rolling.
- Surface blemishes (indicated by kinks across the coil width) caused by the winding arbor. Horizontal creases near a coil ID or OD if rewound.
- Finish for the most common Cold Rolled surface with a uniform dull finish. Usually suitable for painting. Profilometer range usually about 35–65 micro inches.
- A method of shearing or blanking to meet closer than standard width, length and out–of–square tolerances.
- A surface hump down the length of a sheet/coil.
Rimmed Steel (OLD STEEL MAKING)
- A low carbon steel grade that is cast into molds without using strong deoxidizing elements (aluminum or silicon) so that the principal steel making reaction, carbon combining with oxygen to form a gas, continue as the liquid metal solidifies. The marked evolution of the gas (CO) causes the surfaces nearest the mold walls to be lower in carbon, sulfur and phosphorus than the core of the ingot. This grade exhibits a wide range of chemistry across the cross section of the strip. Sheet and strip products produced from rimmed steel ingots have excellent surface characteristics.
- A test measurement to determine hardness. In low–carbon steels, it can indicate approximate yield and tensile strengths. To get tensile strength simply multiply Rockwell by 1,000. For example B53 will approximate a 53,000 tensile strength (53 x 1,000 = 53,000). To get yield strength, multiply Rockwell by 1,000 and subtract total by 20,000. For example, a B53 Rockwell will approximate a 33,000 yield (53 x 1,000 - 20,000 = 33,000).
Rockwell Hardness Conversion
- A test for determining the hardness of sheet steel. Can be converted to another scale by referring to the tables in ASTM E140.
Rockwell Hardness Number
- A number derived from the net increase in depth of impression, as the load on an indenter is increased from a fixed minor load to a major load and then returned to the minor load. Penetrators for the Rockwell hardness test include carbide balls of several specified diameters and a diamond sphere conical penetrator having an included angle of 120 degrees with a spherical tip and a radius of 0.2mm. Rockwell hardness numbers are always quoted with a scale symbol representing the penetrator, load and dial used. To minimize errors and misunderstanding, it is suggested that hardness numbers be specified to the same scale as that used during testing. Rockwell and Rockwell Superficial scales using the 1/16th inch diameter carbide ball indenter are commonly used for testing sheet steel. In thin sheet material, lighter loads and scales should be used depending on thickness and hardness. Rockwell hardness test results are used as indications of the formability of sheet material and to express tempers (see ASTM E18, Standard Method of Test for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials). When a Rockwell Hardness Test forces a cone–shaped diamond or carbide ball into the specimen being tested under standard pressure, the depth of penetration is an indication of the Rockwell Hardness.
- An extraneous chip or particle of metal rolled into the surface of the product.
- A defect resulting from scale being rolled into the steel surface.
- This is extraneous matter rolled into the surface of the sheet.
- Fabrication method in which steel (usually coil) is linearly, progressively deformed by passing through a consecutive series of rolls to produce a predetermined profile.
- The uniform ground finish on the work rolls, which is imparted to the sheet or plate during rolling.
- A rope–like appearance in the rolling direction after the metal has undergone severe deformation. This condition is caused by the presence of irregular grains in the rolled product before being deformed.
- Corrosion caused by exposure over time to the atmosphere, chemicals or other injurious elements. Usually, Hot Rolled and Cold Rolled turn orange/red. Galvanized and Aluminized turn white to black.
- Society of Automotive Engineers.
Salt Spray Test
- A procedure to determine the coating longevity of steel, when exposed to corrosive effects of saltwater.
- Iron oxides, which form on the surface of Hot Rolled during, or subsequent to, rolling. Scale can be removed by Pickling.
- An iron oxide formed on the surface of hot steel, sometimes in the form of large sheets, which fall off when the steel is rolled.
- A scratch pattern surface induced by brushing with textured rolls. Can often reduce or eliminate light rust.
- Scoring or indentation of varying degrees in the surface. Usually caused by rollers or during handling.
- Material that does not meet the original customer's specifications in terms of thickness, width, surface, chemistry or physical properties. Sold at a discount compared to prime steel, secondary may be quite suitable for other applications.
- A surface crack sometimes caused during casting or hot rolling.
- A non–uniformity in chemical composition occurring during solidification. Often associated with internal defects, i.e. lamination and piping.
Semi Killed Steel (OLD STEEL MAKING)
- A low–carbon steel grade that is cast into molds using very carefully measured amounts of the strong deoxidizing elements (aluminum or silicon) so that the principal steelmaking reaction, carbon combining with oxygen to form a gas, continues as the liquid metal solidifies. The addition the deoxidizing agent alters the evolution of gas (CO). The amount evolved is more than would be observed in the casting of killed steel, but significantly less than the amount evolved by a rimmed steel. The amount of deoxidizing agent used determines the amount of gas evolved. Semi–killed sheet chemistry exhibit variable degrees of uniformity somewhat intermediate to the killed and rimmed grades.
- Flat–rolled steel generally less than .250" in thickness and wider than 12". The formula to calculate the steel sheet weight is: thickness (in.) x width (in.) x length (in.) x density (.2833 lb./cubic inch).
- The contour of a coil's sides and edges. Ideally, they are free of damage, smooth and straight.
- A deoxidizing element in steelmaking; very slight tendency to segregate; generally detrimental to surface quality. Chemical symbol Si.
- Seam or inclusion at surface resembling a blister. Could lead to metal fracture.
- The area of an uncoated sheet, which is frequently caused by equipment malfunction.
- A semi–finished steel block having an oblong cross–section in which width is at least twice the thickness. It differs from a bloom, which has a square or nearly square cross–section.
- An edge produced from slitting; typically tighter width tolerances than mill edge or cut edge.
- Close tolerance rotary cutting of flat rolled products. This is a continuous cutting of a sheet or coil into narrower widths. The longitudinal splitting of the overall width of a flat product through rotary knives mounted on a rotating arbor to reduce the original width or to cut two or more separate strips.
- Thin fragments of steel, which are part of the material, but only partially attached. Typically caused by surface damage or internal inclusions which are subsequently rolled. They are somewhat similar in appearance to skin laminations but usually more prominent.
- A dark film of debris, sometimes covering large areas, deposited on the sheet during rolling.
- A series of reversing lateral bows in coil products. This condition is caused by a weaving action during an unwinding or rewinding operation.
- Regular Spangle, (a.k.a. bright Spangle) is produced by allowing the zinc to cool and crystallize, normally without restriction, to form a flower like pattern on the surface about 1/2" in diameter and larger. This type of sheet is used for ductwork, pails, garbage cans. etc. Minimized or minimum spangle is produced by restricting or retarding the spangle growth by the use of steam, water or air applied as the strip emerges from the molten zinc pot. The process not only restricts the diameter of the spangle, but also reduces the profile or height of the spangle. A sheet coil produced with this surface is usually used for painted products. Regular apatugle is not usually suitable for painting, because if only a thin coat of paint is used the spangle might show through. Also, the high relief on regular spangle does lend itself to a smooth painted surface. It is also usually advisable, if the steel is to be painted or laminated on a continuous coating line, to order it extra smooth. That is, skin passed or temper rolled after galvanizing.
Special Killed Steel (Drawing Quality–DDS)
- A sheet with maximum uniformity used for severe drawing or forming operations. Has maximum ductility plus freedom from age hardening and fluting. Conforms to ASTM A620 now ASTM A1008.
Special Killed Steel (Old Steel Making)
- This is generally a low–carbon aluminum killed steel, although the producer sometimes uses other deoxidizers to obtain the desired characteristics. Special killed steel is intended for applications where Cold Rolled carbon sheet is to be essentially free from significant changes in mechanical properties over a period of time. This product is normally supplied to be essentially free from surface disturbances, such as stretcher strains or fluting, without roller leveling. Special killed steel can be used for Hot Rolled carbon sheet steel when it is to be cold reduced by the purchaser and properly processed to have the characteristics described above.
- Referring to Galvanized or Aluminized, a severe coating buildup resulting in a non–uniform surface.
- A coil having edges that are turned up or down (like a spool of thread).
- Designation for Structural Quality.
- Surface discoloration, which may vary from dark brown to white and is produced during thermal treatment by incomplete evaporation and/or oxidation of the surface by the lubricants.
- Strip steels with high chrome content to impede corrosion.
- Metalworking operation involving the cutting and forming of steel using tooling and dies.
- Non–uniform coating application, which results in absence of coating in certain areas. This condition can be caused by the mismatch of an applicator roll and sheet surface velocities.
- These are arc–shaped types of coil breaks, usually located near the middle of the sheet.
- The amount of elongation or compression when steel is subjected to a specific load.
- A banded condition caused by non–uniform coating during the initial application process.
- Surface discoloration, which may vary from grey to black, is parallel to the direction of rolling, and rolled in foreign debris. It is usually extraneous material from an overhead location that drops onto the rolling surface and is shallow enough to be removed by etching or buffing.
- A streak with a helical pattern transferred to rolled products from the work rolls.
- A streak on the sheet surface in the rolling direction caused by transfer from the leveler rolls.
- A non–uniform surface appearance, parallel to the rolling direction. It is caused by an uneven wiping action on the upper backup roll(s) of a mill, which transfers first to the work roll and then to the rolled product.
- The force per unit area caused by externally produced forces.
- Flatness exceeding commercial tolerances, often specified for panels or similar applications.
- A method of developing superior flatness in a steel sheet by gripping the ends of the sheets with especially designed grippers and pulling it mechanically just beyond its yield point. More commonly termed as tension leveling, a method of developing superior flatness in a steel coil by passing it through equipment designed to pull the strip, while it is in motion, just beyond its yield point.
- These are vein-like surface defects, which may appear in low-carbon steel during cold deformation. They are associated with the irregular movement of the metal when it is being strained at the yield point. Stretcher strains are also known as "Luder's lines," "strain figures," etc.
- A coating flow defect appearing as near–parallel lines.
- 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).
Structural Quality (SQ)
- When mechanical property values other than bend tests, such as tensile or yield point elongation, Rockwell hardness or similar tests are specified or required. This quality is also identified as physical quality and the term structural (physical) quality is now in use.
- The base metal for coated steel products can be either Hot Rolled, P&O, Cold Rolled steel or high-strength low-alloy.
- A chemical element that tends to lower ductility and weld-ability; prone to foster segregation; impairs surface quality. Chemical symbol S.
- A spangle pattern somewhat like a regular (minimized) spangle finish, except the spangles do not exhibit as much surface relief. This finish is often desired for pre-painted galvanized sheet.
- Minute surface cracks on rolled products, which can be caused by caster cracks.
- A mechanical procedure in which a steel sheet is bent 180 degrees with the inside bend diameter expressed in terms of the material thickness. A bend of 1T is equivalent to the material thickness; a 2T bend equals twice the material thickness.
- A progressive series of rolling mill stations in which coils are cold worked, primarily to reduce thickness and improve flatness.
- Lateral stacking, primarily in one direction, of wraps in a coil so that the sidewall of the coil is conical rather than flat. Usually caused by improper alignment of rolls over which the steel passes before rewinding.
- A condition produced in sheet steel by mechanical, chemical or thermal treatment. A given steel may be fully-softened to an annealed temper, be cold worked to the hard temper or worked further to a spring temper. Intermediate tempers produced by cold working (rolling) are called "quarter-hard," "half-hard," and "three-quarters hard," and are determined by the amount of cold reduction.
- The flexing of a sheet by passing it through a series of rolls to improve flatness. Usually reduces or eliminates crossbreaks and center buckle.
Temper Passing (skin rolling)
- Bands and annealed Cold Rolled are especially susceptible to wave, center buckle, crossbreaks and minor surface defects. A slight cold reduction corrects these problems. Temper rolling can vary from 0.05 to 3.0%.
- The maximum tensile stress, which a material is capable of sustaining. Tensile strength is calculated from the maximum load during the tension test, carried to rupture and the original cross sectional area of the specimen.
- This term denotes a mechanical operation wherein sheet steel in coil form is passed through a unit, which stretches the product beyond its yield point. This is a process for improving flatness in coils by pulling in tensions. The purpose is to provide a sheet with superior flatness characteristics. The stretch unit may be a separate operation or in tandem with another processing unit, such as a galvanizing line.
- See Long Terne Metal.
- Sheet and strip products, sold at the theoretical weight calculated on the basis of the minimum specified thickness, width and length.
- Chemical symbol Sn.
- Very light gauge Cold Rolled with electrolytically-deposited tin on both sides. Used for the manufacturing of cans.
- 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.
- Theoretical Minimum Weight (See Theoretical Weight).
- 1: Permissible variation in dimensions (thickness, width, length, diagonal). 2: The allowed range of deviation from a specified dimension of specified chemical element.
- 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.
- A coil that is partially electrogalvanized coated and partially bare Cold Rolled.
- Oxidation occurring during shipment. Typically appears most prominently on ID and OD wraps, top and bottom sheets, and at edges. It may manifest in sporadic spots within a coil or sheet bundle.
- 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.
- Designates unexposed part.
- See tensile strength.
Ultimate Tensile Strength
- The maximum stress, which a material is capable of sustaining under a gradual and uniformly applied load.
- 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.
- Often used in high-strength low-alloy steels for increased yield and tensile strengths. Chemical symbol V.
- Cold Rolled sheet that has been processed for porcelain enameling operations.
Vitreous Enameling Iron
- A type of Cold Rolled sheet produced for porcelain enameling. It has very low carbon levels and a rough matte finish (typically 55+ micro inches).
- An internal cavity produced during the solidification process during casting.
- Superficial oxidation of the surface with a water film in the absence of circulating air, it is held between closely adjacent metal surfaces such as between wraps of a coil or sheets of a stack. The appearance varies from iridescent in mild cases to white, gray or black in more severe instances.
- An out of flat condition relative to the order or ASTM flatness specifications. Can occur across the width or merely at edge(s).
- A joining or union of steel, created by the application of very high temperatures.
- The area where coils have been welded together to form a single, longer length for more efficient production. The area near the weld is typically of poor quality in terms of strength, surface and coating adhesion.
- The adaptability of steel to welding, typically influenced by chemical composition, surface finish, coating type and weight.
- On galvanized, corrosion that occurs when material is exposed to moisture and is unable to quickly dry, often between adjacent wraps or sheets. Varies in severity and coverage area. Also see water stain.
- The increase in resistance to deformation as a result of cold working, i.e. rolling, rollforming.
- A condition in a coil due to insufficient tension, which creates a small void between the adjacent wraps.
- A coating defect of small ridges or folds resembling a small prune skin.
- Designates no coating, i.e. one-side.
- The amount of net finished product generated in relation to the initial gross amount (Not to be confused with Yield Point).
- The load per unit of the original cross-section area at which a marked increase in the deformation of the specimen occurs with out increase of load. This is usually calculated from the load determined by the drop of the beam of the testing machine or by use of dividers.
Yield Point Elongation (YPE)
- Refers to a non-uniform elongation of steel and resulting susceptibility to Luder's bands (surface strain lines, resembling crossbreaks). 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.
- 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 point 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" of its length becomes 1.002" after loading to the yield strength. It is lower than tensile strength, since the steel will "give" before it fractures.
- 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 zinc, the slower the corrosion. Chemical symbol Zn.
- Among the most common surface blemishes peculiar to galvanized sheet steel are sometimes encountered. They feature coarse coating and zinc ridges. When zinc adherence is good and proper coating weights are present, these surface blemishes have no harmful effect on the life of the sheet.
- Steel covered by the roll-coated process with a base coat of zinc-chromium alloy, and a topcoat of a weld-able zinc-rich primer.