Glossary of Terms

Jump To: A, B, C, D, E, F, G, H, I, K, L, M, O, P, Q, R, S, T, U, V, W, Y

A

AAR – Association of American Railroads.

AASHTO – American Association of State Highway and Transportation Officials.

ABS – American Bureau of Shipping

AGING – 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.

AISI – American Iron and Steel Institute

ALLOY STEEL – Steel is considered to be an alloy steel when: Manganese over 1.65%, silicon over 0.60%, copper over 0.61 %, or a definite minimum quantity of alloying elements is specified. These specific elements impart special properties. The added alloying elements provide increased strength … corrosion resistance … and ability to have increased hardenability.

ALLOY COATED – When a metallic coating, through heat treating, becomes a part of the base metal, i. e. galvannealed, aluminum-zinc, long ternes.

Aluminum Coated Steel Sheets – Type I – A carbon steel product continuously hot dipped coated with an aluminum coating containing 5 to 10 percent silicon. Heat resistant grade used for heat exchangers and automotive mufflers.  

Aluminum Coated Steel Sheets – Type 2 – A carbon steel product continuously hot dipped coated with a pure aluminum. Combines the strength of the steel substrate and the corrosion resistance and reflective of the pure aluminum

Aluminum-Zinc Alloy Coated Steel Sheets (Galualume) – 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 or heat resistance, or both.

ANNEALING – Annealing is a thermal treatment used to soften the steel, to improve machinability, to improve or restore ductility and to reduce internal stresses. Annealing consists of heating the steel to a temperature above or within critical range, holding a sufficient length of time at the designated temperature and then cooling in the furnace at a slow rate.

ANSI – American National Standards Institute – Adopts ASTM specifications as American National Standards.

ASTM – American Society for Testing and Materials.

ATMOSPHERIC CORROSION – Atmospheric corrosion occurs when unprotected steel is exposed to air containing moisture. The attack is generally uniform on plain surfaces and may be affected by corners.  Damage can usually be measured in terms of loss of thickness in thousandths of an inch (mils) per year. The rate of attack, however, varies with time, and therefore it is not possible to describe accurately with an average value.

 B

BASIC OXYGEN PROCESS – B.O.P. – Steel making method in which substantially pure oxygen is introduced to facilitate the melting process. The furnace in which this method is accomplished is known as a BOF (Basic Oxygen Furnace).

BLACK PLATE – Cold reduced sheet steel ranging in width from over 12 inches to less than 32 inches and in gauge from 29 (.0135) and lighter, in coil or cut lengths, and within the uniform Classification of Flat Rolled Carbon Steel Products.  

BLISTERS – A raised irregularly-shaped area on surface that when ruptured, may reveal a light-colored non-metallic substance.

BORON (AS AN ELEMENT) – Added to steels for purpose of achieving a special alloying effect. Principally used to improve machinability and formability at a particular level of hardenability.

BOX ANNEALING – Annealing steel by heating in a sealed container under conditions that minimize oxidation.

BRINELL HARDNESS – In the Brinell Hardness Test, the value obtained by dividing the applied load (in kilograms) by the surface area of the impression (in square millimeters) resulting from forcing a hard steel or carbide ball into the steel test sample. The higher the number, the harder the steel.

Black Plate – 1. The uncoated steel sheet product before electro-tinning. 2. An A.I.S.I. Flat Rolled Carbon Steel Product Classification for a cold rolled coilor cut length product ranging In width from over 12″ to less than 32″, and 29 gauge (0. 135″) or lighter.

Bonderized – A proprietary name for a phosphate treated steel or metallic coated substrate. See Phosphatized.

Burr – A thin ridge of rough mess left by cutting operations such as slitting, trimming, shearing, blanking, etc.

Burred Edge –A thin turned down edge on sheet resulting from shearing.

 C

CAMBER – Camber is the greatest deviation of a side edge from a straight line, the measurement being taken on the concave side with a straight edge. The camber tolerance for sheet in coils is 1/2 inch in any 20 feet of length.

CAPPED STEEL – Capped Steels have characteristics similar to those of rimmed steels, but to a degree intermediate 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 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. Gener- ally, steels of this type are above .15% carbon and are applied to sheet, strip skelp and tin plate.

CARBON STEEL – 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 d2aa = exceed the following percent- ages: Manganese:1.65; Silicon:0.60; Copper:0.60 (when specified).

CHEMISTRY – (Effects of Common Elements in Miscellaneous Section)

Chemical Treatment – 1. Process for passivating a galvanized coating to retard the formation of “wet storage stains” during shipment and storage. Most chemical treatment isused to prevent storage stains. 2. Process for preparing a surface for painting. See Phosphatized.

CHROMIUM (AS AN ELEMENT) – Principally used to increase hardenability and improve wear and corrosion resistance.

COIL BREAKS – Creases of ridges which appear as parallel lines, trans- verse to the direction of rolling. They generally extend across the width of the sheet (see Defects section).

Coil Coated Sheet Steel – Also termed prepainted, is a sheet steel product exhibit a paint, plastic, nonmetallic, or nonmetallic fflm on one or both of its surfaces.

COIL WELD – A coil weld is a joint between two lengths of metal within a coil. Coil welds are not always visible in a cold reduced product (see Defects section).

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.

COMMERCIAL QUALITY (CO) – Sheet of this quality is for uses involving simple bending or moderate drawing. Commercial Quality sheet can be bent flat upon itself in any direction at room temperature.

CONTINUOUS ANNEALING – 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.

CONTINUOUS CAST STEEL – There is a large scale production of con- tinuous 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.

CONTINUOUS ROLLING – A process whereby slab reheating is either eliminated or substantially reduced. It occurs in a continuous casting operation. As the slab is formed, it is moved immediately to the finishing area for conversion into a sheet product.

COPPER (AS AN ELEMENT) – Added to steel’s for the purpose of improving the steel’s resistance to corrosion.

CORROSION – Gradual chemical or electrochemical attack on a metal by atmospheric moisture or other agents.

CORROSION RESISTANCE – The ability of a metal to withstand attack in an environment that is conductive to chemical or electrochemical reaction.

 D

DEEP DRAWING – The process of working metal blanks in dies on a press into shapes which are usually more or less cup-like in character.

DEEP DRAWING QUALITY – SPECIAL KILLED – FULLY STABILIZED (DDQSK-FS) – Coated sheet of this quality is characterized by excellent uniformity and exceptional formability. DDOSK-FS sheet is produced from vacuum degassed steel to achieve a very low carbon content. Stabilizing elements are added during steel production which combine with carbon and nitrogen to make it interstitial free. The final product exhibits a high resistance to thinning during drawing. It is non-aging which eliminates coil breaks, strain lines and fluting during fabrication.

DEEP DRAWING QUALITY – SPECIAL KILLED – EXTRA LOW CAR- BON (DDQSK-ELC) – DDQSK-ELC sheet is also degassed during steel production to achieve a very low carbon content. The primary use will be for continuously annealed Hot Dipped Galvanized Sheets. Coated sheet of this quality will have excellent uniformity and formability. The formability will not be as good as DDQSK-FS and it will exhibit the effects of aging, although they will not be severe.

DRAWING QUALITY (DQ) – As compared with sheet of Commercial Quality, Drawing Quality sheet has a greater degree of ductility and is more consistent in performance. The greater ductility and uniformity results from higher standards of production, selection and processing of the steel.

DRAWING QUALITY – ALUMINUM KILLED (DQAK) – Specially killed steel using aluminum as the deoxiclizing agent. “

DRAWING QUALITY – SPECIAL KILLED (DQSK) – 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 QUALITY – SPECIAL KILLED – DENT RESISTANT, BH SERIES – Sheet products of this quality are produced from aluminum- killed steel and offer a unique combination of as-received formability and final properties after fabrication. DQSK-DR sheet has excellent formability yet exhibits significantly higher yield strength and dent resistance after parts are manufactured. Although DQSK-DR sheet is essentially non-aging at room temperature, it gains strength from work hardening during fabrication and from carbon-aging during a subsequent thermal cycle, such as paint-baking.

DUCTILITY -A measure of the ability of steel to undergo permanent changes without rupturing.

E

EDGES – Mill edge is the normal edge produced in hot rolling and it 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 = gliga 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 is usually made in the continuous pickling operation prior to the cold reduction process.

EDGE BREAKS – Edge breaks are short creases which extend in varying distances from the side edge of the temper rolled sheets (see Defects Section).

ELECTRICAL FURNACE (EF) – A method to produce steel…basically from scrap metal. (See Steel making section for details and flow charts.

ELECTRICAL SHEET – 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 proper- ties superior to Type 1. The improved magnetic properties are attained by special mill processing and controlled chemical com- position, 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 opti- mum magnetic properties, it is necessary that the consumer anneal to adequately decarburize and promote grain growth.

ELONGATION – In tensile testing, the increase in the gauge length, measured after fracture of the specimen within the gauge length, usually expressed as a percentage of the original gauge length.

 Applications – motors, generators, ballast transformers. Availability – Coils and cut lengths. 

EMBOSSED OR EMBOSSING – Embossing (pattern rolling) is the imprinting of a particular design into a Cold Rolled or Coated Steel product. The design is transmitted by passing between rolls previously etched with the particular pattern. The ductility of the material is dependent upon its condition prior to embossing and also the design and imprinted depth of the pattern. Any repetitive design can be imprinted on one side (coining) or both sides (embossing).

F

FATIGUE – The tendency for a metal to break under conditions of repeated cyclic stressing considerably below the ultimate tensile strength.

FINISHES – The degree of smoothness or luster of the surface of Cold Rolled steel (See Surface Finishes).

FLATNESS – Flatness is a measure of a cut length sheet’s ability to con- form to a flat horizontal surface. Maximum deviation from that surface is the degree to which the sheet is out of flat.  

FLUTING – 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 (see Defects section).

FLOPPERS – Floppers are 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 (see Defects section).

FORMABILITY – The ability to be shaped without injury to the steel in the finished product.

FRICTION DIGS – A series of relatively short scratches variable in form and severity (see Defects section).

 G

GHOST LINES – Ghost lines are lineal irregularities in the surface which develop in drawing. They are parallel to the direction of rolling (see Defects section).  

GLOSSMETER – Instrument used to compare the reflectivity of finishes.

GRAIN SIZE – Traditionally, steels have been referred to as “fine” or 11coarse” grain in reference to the austenitic grain size as determined by the McQuaid-Ehn test. A “fine grain” steel is required to have a grain size number of 5 or higher; a “coarse grain” steel is required to have a grain size number of 5 or lower.

H

HARDENABILITY – Refers to the depth to which hardness penetrates. It is that property which determines the depth and distribution of hardness induced by quenching.

HARDNESS – See Tempers, CR Sheet.

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.

HEALED OVER SCRATCH – Healed Over Scratch is a scratch that occurred in a mill operation and was partially masked in subsequent rolling. It might open up during forming (see Defects section).

HIGH STRENGTH SHEET STEELS UNIFORM DESIGNATOR SYSTEM The uniform designator for High Strength Sheet, steel has five basic components: (1) the sheet product prefix, (2) the minimum yield strength in ksi, (3) a chemical composition classification, (4) a classification for the deoxidization practice, and (5) a classification for minimum tensile strength:

(1) Sheet Products Prefix – HR = Hot Rolled

CR = Cold Rolled

GP = Galvanized Product LT   Long Terne

GL   GALVALUME” Sheet

(2) Yield Strength – Numerical description of minimum yield strength in ksi.

(3) Chemical Composition – Each steel is designated by a letter classification –

S = Structural Quality X = Low Alloy

W = Weathering D = Dual Phase

(4) Deoxidization Practice –

F = Killed Plus Sulfide Inclusion Control K = Killed

0 = Non-Killed (Rimmed, Capped or Semi-Killed)

(5) Tensile Strength – Numerical description of minimum tensile strength in ksi (only the last two digits are used for tensile strengths above 100 ksi).  

HIGH STRENGTH QUALITY – High Strength Quality is applicable when a minimum yield strength of 35 ksi and/or a minimum tensile strength of 50 ksi is specified. The required strength levels may be achieved without the addition of any alloy(s) beyond carbon and manganese. The combination of thickness, specific strength and end use application will determine the acceptability of the ordered strength level and name.

HIGH STRENGTH STEEL – 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.

HSLA – High Strength, Low-Alloy Steels – A specific group of steels with chemical compositions especially developed to impart higher mechanical properties and/or improve atmospheric corrosion resistance.

HOT ROLLED – Describes steel products that are brought to approximate finished size by rolling at elevated temperatures.

 I

IMPACT TOUGHNESS – The ability to withstand a force without breaking.

INCLUSIONS – Particles of non-metallic material usually oxides, sulfides, silicates and such which are entrapped mechanically or are formed during solidification or by subsequent reactions within the solid metal.

IRON – 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.

K

KILLED STEEL – Steel deoxidized by silicon or aluminum to reduce the oxygen content to a minimum so that no reaction occurs during solidification of the metal. Killed Steels have more uniform properties and chemical composition than other types.  

KSI – K Equals 1000 PSI  … thus the term is actually K (1000) PSI. The P has been dropped  … and KSI is the new term (i.e. 50 KSI = 50,000 PSI).

L

LAMINATIONS – Imperfections resulting from the presence of blisters, seams or foreign inclusions, and sometimes visible on the surface of the metal (see Defects section).

LUBRICITY – Slipperiness. The ability of steel sheet to slide in a forming die.

M

MECHANICAL PROPERTIES – Assist in predicting the ability of steel to withstand service loadings without permanently deforming or rupturing and the ability to undergo large or permanent deformations. These properties are expressed by yield, tensile elongation, reduction in area or in elastic reactions of a material to an applied force. Sometimes designated erroneously as “physical proper- ties”.

 
0

OILED – 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.

OLSEN TEST – This is a cupping test made on an Olsen machine 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.

OPEN HEARTH FURNACE – The original method of turning iron into steel. There are only a few open hearth furnaces left, as they have be- come obsolete due to the introduction of the Basic Oxygen Furnace which is faster and thus less costly.

ORANGE PEEL – Orange Peel is the course grain condition which be- comes evident during drawing (see Defects section).

ORANGE PEEL STRAIN – Orange Peel Strain is a pebbly surface condition which develops during drawing (see Defects section).  

OUT-OF-SQUARE – The difference between two diagonal measurements of a square or rectangular or 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.

P

PATTERN ROLL – See Embossed or Embossing

PHYSICAL PROPERTIES (OF STEEL) – Properties which pertain to the physics of a material, such as density, electrical conductivity, a coefficient of thermal expansion. Not to be confused with mechanical properties.

PICKLING – Removal of mill scale or oxide by immersion of steel in a dilute solution of sulphuric or hydrochloric acid, then rinsed and dried.

PIG IRON – Blast furnace iron.

PINCHERS – Pinchers are fern-like ripples or creases usually diagonal to the rolling direction (see Defects section).

PIPE LAMINATION – Pipe Lamination is a separation midway between the surface containing oxide inclusions (see Defects section).

P.M. – Pounds per inch of width.

PLATING QUALITY – 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 A-366.

PORCELAIN ENAMELING SHEETS – Sheet steel for porcelain enameling is chemically treated 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, as shown below:

 Type I – This type 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 11 – This type 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 11 can be varied to provide either maximum resistance to sag or good formability. Sheet steel for porcelain enameling can be produced to stretcher leveled standard of flatness, re-squared or sheared into circles or sketches.

PRE-LUBE – Coating applied to enhance formability.

PROFILOMETER – An instrument that measures surface-roughness height in micro-inches. The height is measured as the absolute deviation from a mean surface.

P.S.I. – Pounds per square inch

 Q

QUALITY – Refers to the suitability of the steel for the purpose or purposes for which it is intended (see Commercial Quality, Drawing Quality, Structural Quality, etc.

R

REDUCTION – Reducing thickness of sheet or strip by hot or cold rolling.

RESQUARING – A method of shearing to meet closer-than-standard width, length and out-of-square tolerances.

RIMMED STEEL – This type of steel, when properly made, can be cast into ingots having a minimum of pipe along with a good surface, though they are subjected to segregation. Given the same rolling conditions, rimmed steel is softer, has a coarser grain and exhibits more variation in mechanical properties than does strip from other types of steel. Rimmed steels are characterized by having a rim of practically pure iron which provides very good surface quality. Because of the softness obtainable on rimmed steel, sheets of this type have very good forming qualities. Although high carbon (above .15%) sheets are not normally produced from rimmed steel, this grade can be made in carbon contents up to about .25% C.

ROCKWELL HARDNESS – (HRB OR HRC) – A measure of hardness determined by either a diamond (Rockwell C Scale) or hard steel ball (Rockwell B Scale) is forced into the surface of a specimen plate, under minor and major loads. The difference between the depths of impressions is the Rockwell Hardness Valve.

ROCKWELL HARDNESS NUMBER TEST – A number derived from the net increase in depth of impression as the load on an indenter is in- creased from a fixed minor load to a major load and then returned to the minor load. Penetrators for the Rockwell hardness test include steel balls of several specified diameters and a diamond sphereconical penetrator having an included angle of 120 degrees with a spherical tip having 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 1/1 6th inch diameter steel ball indenter are commonly used for testing sheet steel. In this 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 El 8, Standard Method of Test for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials).  

ROCKWELL HARDNESS TEST – Forcing a cone-shaped diamond or hardened steel ball into the specimen being tested under standard pres- sure. The depth of penetration is an indication of the Rockwell Hardness.

ROLLED-IN-DIRT – This is an extraneous matter rolled into the surface of the sheet (see Defects section).  

ROLLED-IN-SCALE – This consists of scale partially rolled into the surface of the sheet (see Defects section). 

ROLLER LEVELING – A mechanical operation, where a coiled sheet and/ or plate is passed through leveling and flattening equipment.

S

SCALE – 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.

SEMI-KILLED – A type of steel having a greater degree of gas evolution than in killed steel, but less than in capped or rimmed steel. Semi-killed steels are characterized by variable degrees of uniformity in composition which are intermediate between those of killed and rimmed steels.

SKIN LAMINATION – This is a sub-surface separation which usually results in a surface rupture (see Defects section).

SLAB – A semi-finished steel block having an oblong cross-section in which width is at least twice its thickness. It differs from a bloom which has a square or nearly square cross-section.

SLIVERS – These are surface ruptures somewhat similar in appearance to skin laminations but usually more prominent (see Defects section).

SLITTING – Close tolerance rotary cutting of flat rolled products.

SPECIAL KILLED STEEL – This is generally a low carbon aluminum killed steel, although the producer sometimes uses other de-oxidizers 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.

SPECIAL KILLED STEEL (DRAWING QUALITY) – A sheet with maxi- mum uniformity used for severe drawing or forming operations. Has maximum ductility plus freedom from age hardening and fluting. Con- forms to ASTM A-620.  

SPECIAL SOUNDNESS QUALITY – Special soundness is produced by employing special steel making practices (including controlled phosphorus and sulfur) and finishing practices. With these practices we can obtain a high degree of internal soundness, homogeneity, uniformity of chemical composition and grain control.

SPECIFIED HARDNESS – For some applications customers choose to specify a minimum, maximum or a range of hardness. Minimum hardness is often specified to meet and use requirements. Often, a maximum hardness is specified to assure adequate formability. The former Intermediate Temper Grades are now designated as Specified Hardness.

S.S.C.I. – Abbreviation for Steel Service Center Institute.

STRAND CASTING – Strand casting is the direct casting of steel from the ladle into slabs. When two or more heats are cast without interruption, the process is called continuous strand casting. In strand casting, a heat of steel is tapped into a ladle in the conventional manner. The liquid steel is then teemed into a tundish which acts as a reservoir to provide for a constant casting rate. The steel flows from the tundish into the casting machine and rapid solidification begins in the open ended molds. The partially solidified slab is continuously extracted from the mold. Solidification is completed by cooling the moving steel surface. More than one strand may be cast simultaneously, depending upon the heat and slab size. A reduction in size may be carried out by hot working the product as it exists from the strand prior to cutting the cast section to length. Chemical segregation is minimized due to the rapid solidification rate of strand cast product. Steel produced from a strand casting operation is always fully killed steel … thus is generally considered to have excellent surface quality,  

STICKER BREAKS – These are arc-shaped types of coil breaks usually located near the middle of the sheet (see Defects section).  

STRESS RELIEVING – A process of reducing residual stresses in a metal object by heating the object to a suitable temperature and holding for a sufficient time. This treatment may be applied to relieve stresses induced by flattening, straightening, machining or welding.  

STRETCHER LEVELING – A method of producing unusual flatness in steel sheets by stretching them in a hydraulic device (see Tension Leveling).

STRETCHER STRAINS – 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. (see Defects section).

STRUCTURAL QUALITY (STRL-QUAL) – When mechanical property values other than bend tests, such as tensile or yield point elongation, Rockwell hardness or similar tests are specified or required.

 T

TENSION LEVELING – 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 Tension Leveling).

TEMPER – A condition produced in sheet steel by mechanical, chemical or thermal treatment. A given steel may be in the fully softened of annealed temper, or it may be cold worked to the hard temper, or further to spring temper. Intermediate tempers produced by cold working (rolling) are called “quarterhard”, “half-hard”, and “three-quarters hard”, and are determined by the amount of cold reduction.

TENSILE STRENGTH – 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.

THEORETICAL MINIMUM WEIGHT (TMW) CALCULATION FORMULA – TMW = Thickness x Width x Length x Density Factor of Steel Example:

Thickness – .0250 min. inch Width –     48.00 inches

Length –    10,000 ft. = 120,000 inchei,’

Calculation -.0250 x 48.00 x 120,000 x.2833 = 40,795 lbs. TMW

THEORETICAL WEIGHT – Sheet and strip products, sold at the theoretical weight calculated on the basis of the minimum specified thickness, width and length.  

TOLERANCE – Specified limits of deviation from a dimension.  

U

ULTIMATE STRESS – See Tensile Strength.

ULTIMATE TENSILE STRENGTH – See Tensile Strength.

UNS – The Unified Numbering System has been developed by ASTM and SAE and several other societies. A UNS number, which is designation of chemical composition and not a specification, is assigned to each chemical composition of a metallic alloy.

 V

VACUUM TREATMENT – Processes designed to remove undesirable gases and/or to improve the internal micro-cleanliness of the product through use of a vacuum facility.

 VITRENAMEL SHEET – Cold Rolled sheet that has been especially processed for porcelain enameling operations (seePorcelain Enamel Sheets).

VITREOUS ENAMEL – See Porcelain Enamel Sheets.

W

WEATHERING STEEL – Another term for high strength-low alloy steel.  

WELDING – The joining of two pieces of metal into one solid piece.

 Y

YIELD POINT – The load per unit of original cross-section area at which a marked increase in the deformation of the specimen occurs without increase of load. It is usually calculated from the load determined by the drop of the beam of the testing machine or by use of dividers.

 YIELD STRENGTH – The stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals. The point measured in psi at which the metal cross section will no longer return to its original shape.

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