Chemical symbol for Carbon.

Chemical symbol for Calcium.

A copper ingot rectangular in cross section intended for rolling.

Calcium (Ca)
In the form of calcium silicate acts as a deoxidizer and degasifier when added to steel. Recent developments have found that carbon and alloy steels modified with small amounts of calcium show improved machinability and longer tool life. Transverse ductility and toughness are also enhanced.

Call Option
A contract that gives the holder the right, but not the obligation, to buy metal futures at a set price (the strike price) on a given date.

Edgewise curvature. A lateral departure of a side edge of sheet or strip metal from a straight line.

Camera Shutter Steel
Hardened, tempered and bright polished extra flat and extra precision rolled. Carbon content 1.25 - Chromium .15.

A dished distortion in a flat or nearly flat surface, sometimes referred to as oil canning.

Normal ability to produce steel in a given time period. This rating should include maintenance requirements, but because such service is scheduled to match the needs of the machinery (not those of the calendar), a mill might run at more than 100% of capacity one month and then fall well below rated capacity as maintenance is performed.
  • ENGINEERED CAPACITY The theoretical volume of a mill, given its constraints of raw material supply and normal working speed.

  • "TRUE" CAPACITY Volume at full utilization, allowing for the maintenance of equipment and reflecting current material constraints. (Bottlenecks of supply and distribution can change over time, capacity will expand or reduce.)

Capped Steel
Semiskilled steel cast in a bottle-top mold and covered with a cap fitting into the neck of the mold. The cap causes to top metal to solidify. Pressure is built up in the sealed-in molten metal and results in a surface condition much like that of rimmed steel.

A compound of carbon with one or more metallic elements.

Carbon ( C )
(Chemical symbol C) - Element No. 6 of the periodic system; atomic weight 12.01; has three allotropic modifications, all non-metallic. Carbon is preset in practically all ferrous alloys, and has tremendous effect on the properties of the resultant metal. Carbon is also an essential compound of the cemented carbides. Its metallurgical use, in the form of coke, for reduction of oxides, is very extensive.

Carbon-arc welding
Arc welding using a carbon electrode or electrodes.

Carbon Free
Metals and alloys which are practically free from carbon.

Carbon Range
In steel specifications, the carbon range is the difference between the minimum and maximum amount of carbon acceptable.

Carbon Steel
A steel containing only residual quantities of elements other than carbon, except those added for deoxidization or to counter the deleterious effects of residual sulfur. Silicon is usually limited to about 0.60% and manganese to about 1,65%. Also termed plain carbon steel, ordinary steel, straight carbon steel.

A case-hardening process in which steel components are heated in an atmosphere containing both carbon and nitrogen.

(Cementation) Adding carbon to the surface of iron-base alloys by absorption through heating the metal at a temperature below its melting point in contact with carbonaceous solids, liquids or gasses. The oldest method of case hardening.

Case Hardening
A generic term covering several processes applicable to steel that change the chemical composition of the surface layer by absorption of carbon or nitrogen, or a mixture of the two, and, by diffusion, create a concentration gradient, so that the outer portion, or case, is made substantially harder than the inner portion, or core. Typical processes used for case hardening are carburizing, cyaniding, Carbo-nitriding, nitriding, induction hardening, and flame hardening.

Cash Price
The current price in the market for cash/spot contracts. LME cash contracts are for delivery two days forward from the trading day.

Cash Today
An LME trade that is carried out after the normal period for a 'cash' trade (i.e. for delivery two business days later) A cash today trade between brokers can only be done prior to the commencement of the official rings at 12.30 and is for delivery on the next business day. Customers' cash today trades must be completed by 12.20 on the trading day before the delivery day. Also referred to as '"tom next"'.

Casing is the structural retainer for the walls of oil and gas wells, and accounts for 75% (by weight) of OCTG shipments. Casing is used to prevent contamination of both the surrounding water table and the well itself. Casing lasts the life of a well and is not usually removed when a well is closed.

(1) A term indicating in the annealed state as Cast Spring Steel Wire.
(2) In reference to Bright or Polished Strip Steel or Wire, the word cast implies discoloration as a shadow.
(3) A term implying a lack of straightness as in a coil set.

Cast Iron
Iron containing more carbon than the solubility limit in austenite (about 2%).

Cast Steel
Steel in the form of castings, usually containing less than 2% carbon.

(1) An object at or near finished shape obtained by solidification of a substance in a mold. (2) Pouring molten metal into a mold to produce an object of desired shape.

Cathodic Corrosion
Corrosion caused by a reaction of an amphoteric metal with the alkaline products of electrolysis.

Cathodic Inhibitor
A chemical substance that prevents or slows a cathodic or reduction reaction.

Cathodic Protection
Reducing the corrosion of a metal by making the particular surface a cathode of an electrochemical cell.

The rapid formation and depletion of air bubbles that can damage the material at the solid/liquid interface under conditions of severe turbulent flow.

Chemical symbol for Columbium

Chemical symbol for Cerium.

A compound of iron and carbon, known chemically as iron carbide and having the approximate chemical formula Fe3C. It is characterized by an orthorhombic crystal structure. When it occurs as a phase in steel, the chemical composition will be altered by the presence of manganese and other carbide-forming elements.

A powder metallurgy product consisting of ceramic particles bonded with a metal.

Chain intermittent weld
An intermittent weld on each side of a joint (usually fillet welds in T and lap joints) arranged so that the welds lie opposite to one another along the joint.

Charcoal Tin Plate
Tin Plate with a relatively heavy coating of tin (higher than the “Coke Tin Plate” grades).

The act of loading material into a vessel. For example, iron ore, coke and limestone are charged into a Blast Furnace; a Basic Oxygen Furnace is charged with scrap and hot metal.

Charpy Test
A pendulum-type single-blow impact test in which the specimen usually notched, is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed, as determined by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.

Charpy Test
A test to measure the impact properties of steel. A prepared test piece, usually notched, is broken by a swinging pendulum. The energy consumed in breaking the test piece is measured in Joules. The more brittle the steel the lower the impact strength. Izod is a similar and more widely used impact test in this country. Both are quoted in the current edition of BS 970.

Chatter Marks
(Defect) - Parallel indentations or marks appearing at right angles to edge of strip forming a pattern at close and regular intervals, caused by roll vibrations.

Chemical Treatment
An aqueous solution of corrosion-inhibiting chemicals, typically chromates or chromate/phosphate.

A method for removing seams and surface defects with chisel or gouge so that such defects will not be working into the finished product. Chipping is often employed to remove metal that is excessive but not defective. Removal of defects by gas cutting is known as “deseaming” or “scarfing.”

Chloride Stress Corrosion Cracking
Cracking due to the combination of tensile stress and corrosion in the presence of water and chlorides.

Chromium (Cr)
An alloying element that is the essential stainless steel raw material for conferring corrosion resistance. A film that naturally forms on the surface of stainless steel self-repairs in the presence of oxygen if the steel is damaged mechanically or chemically, and thus prevents corrosion from occurring.

Chromium-Nickel Steel
Steel usually made by the electric furnace process in which chromium and nickel participate as alloying elements. The stainless steel of 18% chromium and 8% nickel are the better known of the chromium-nickel types.

Cigarette Knife Steel
Hardened, tempered and bright polished, 1.25 Carbon content- Chromium .15. Accurate flatness necessary and a high hardness with Rockwell C 51 to 53. Usual sizes are 4 3/4 wide and 6 wide x .004 to .010.


  • WHAT A gas-based process developed by Lurgi Metallurgie in Germany to produce DRI or HBI (see Direct Reduced Iron and Hot Briquetted Iron).
  • HOW The two-stage method yields fines with a 93% iron content. Iron ore fines pass first through a circulating fluidized-bed reactor, and subsequently through a bubbling fluidized-bed reactor.
  • WHAT
    Method of applying a stainless steel coating to carbon steel or lower-alloy steel (i.e., steel with alloying element content below 5%).

  • WHY
    To increase corrosion resistance at lower initial cost than exclusive use of stainless steel.

  • HOW
    By (1) welding stainless steel onto carbon steel, (2) pouring melted stainless steel around a solid carbon steel slab in a mold, or (3) placing a slab of carbon steel between two plates of stainless steel and bonding them by rolling at high temperature on a plate mill.

Clad Metal
A composite metal containing two or three layers that have been bonded together. The bonding may have been accomplished by co-rolling, welding, heavy chemical deposition or heavy electroplating.

Fracture of a crystal by crack propagation across a crystallographic plane of low index.

Cleavage Fracture
Fracture of a grain, or most of the grains, in a polycrystalline metal by cleavage, resulting in bright reflecting facets.

Cleavage Plane
A characteristic crystallographic plane or set of planes in a crystal on which cleavage fracture occurs easily.
Cluster Mill
A rolling mill where each of the two working rolls of small diameter is supported by two or more back-up rolls.

Chemical symbol for Cobalt.

CO2 flux welding
Metal-arc welding in which a flux-coated or flux containing electrode is deposited under a shield of carbon dioxide.

CO2 welding
Metal-arc welding in which a bare wire electrode is used the arc and molten pool being shielded with carbon dioxide

Cobalt (Co)
(Chemical symbol Co.) Element No. 27 of the periodic system; atomic weight 58.94. A gray magnetic metal of medium hardness; it resists corrosion like nickel, which it resembles closely; melting point 2696°F.; boiling point about 5250°F.; specific gravity 8.9. It is used as the matrix metal in most cemented carbides and is occasionally electroplated instead of nickel, the sulfate being used as electrolyte. Its principal function as an alloy in tool steel; it contributes to red hardness by hardening ferrite.

Coefficient of Expansion
The ratio of change in length, area, or volume per degree to the corresponding value at a standard temperature.

An intermediate rolling process when a hot ingot is reduced to a bloom or slab in a cogging mill.

Coil or Longitudinal Curl
A lengthwise curve or set found in coiled strip metals following its coil pattern. A departure from longitudinal flatness. It can be removed by roller or stretcher leveling from metals in the softer temper ranges.

Coil Breaks
Creases or Ridges appearing in sheets as parallel lines transverse to the direction of rolling and generally extending across the width of the sheet.

Coil Weld
A joint between two lengths of metal within a coil - which is not always visible in the cold reduced product.

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

A process of impressing images or characters of the die and punch onto a plane metal surface.

Coke (Tin) Plate
(Hot Dipped Tin Plate) Standard tin plate, with the lightest commercial tin coat, used for food containers, oil canning, etc. A higher grade is the best cokes, with special cokes representing the best of the coke tin variety. For high qualities and heavier coatings, see (Charcoal Tin Plate).

  • WHAT
    The basic fuel consumed in blast furnaces in the smelting of iron. Coke is a processed form of coal. About 1,000 pounds of coke are needed to process a ton of pig iron, an amount which represents more than 50% of an integrated steel mill's total energy use.

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

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

Coke Oven Battery
A set of ovens that process coal into coke. Coke ovens are constructed in batteries of 10‹100 ovens that are 20 feet tall, 40 feet long, and less than two feet wide. Coke batteries, because of the exhaust fumes emitted when coke is pushed from the ovens, often are the dirtiest area of a steel mill complex.

Cold Cracking
Develops in a weldment after solidification. It forms within hours or days after welding, depending on steel grade, residual stresses and hydrogen content. Proper processing will prevent this problem

Cold Drawing
The process of reducing the cross sectional area of wire, bar or tube by drawing the material through a die without any pre-heating. Cold drawing is used for the production of bright steel bar in round square, hexagonal and flat section. The process changes the mechanical properties of the steel and the finished product is accurate to size, free from scale with a bright surface finish.

Cold-Finished Steel bars
Hot-rolled carbon steel bars with a higher surface quality and strength produced from secondary cold-reduction.

Cold Reduced Strip
Metal strip, made from hot-rolled strip, by rolling on cold-reduction mills.

Cold Reduction

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

Cold Rolled Finish
Finish obtained by cold rolling plain pickled sheet or strip with a lubricant resulting in a relatively smooth appearance.

Cold Rolled Products
Flat rolled products for which the required final thickness has been obtained by rolling at room temperature.

Cold-Rolled Strip (Sheet)
Sheet steel that has been pickled and run through a cold-reduction mill. Strip has a final product width of approximately 12 inches, while sheet may be more than 80 inches wide. Cold-rolled sheet is considerably thinner and stronger than hot-rolled sheet, so it will sell for a premium (see Sheet Steel ).

Cold Rolling
Rolling metal at a temperature below the softening point of the metal to create strain hardening (work-hardening). Same as cold reduction, except that the working method is limited to rolling. Cold rolling changes the mechanical properties of strip and produces certain useful combinations of hardness, strength, stiffness, ductility and other characteristics known as tempers.

Cold Short
The characteristics of metals that are brittle at ordinary or low temperatures.

Cold Shut
A defect produced during casting, causing an area in the metal where two portions of the metal in either a molten or plastic condition have come together but have failed to unite, fuse, or, blend into a solid mass. (See Lamination)

Cold treatment
Exposing steel to suitable subzero temperatures (-85 °C, or -120 °F) for the purpose of obtaining desired conditions or properties such as dimensional or microstructural stability. When the treatment involves the transformation of retained austenite, it is usually followed by tempering.

Cold Working (Rolling)

  • WHAT
    Changes in the structure and shape of steel achieved through rolling, hammering, or stretching the steel at a low temperature (often room temperature).
  • WHY
    To create a permanent increase in the hardness and strength of the steel.
  • HOW
    The application of forces to the steel causes changes in the composition that enhance certain properties. In order for these improvements to be sustained, the temperature must be below a certain range, because the structural changes are eliminated by higher temperatures.
Color Standard
A painted sheet panel with a prescribed color of paint representing the precise color it is intended to produce in the pre-painted sheet. The color standard will preferably also be expressed in terms of physical attributes of hue, lightness and saturation called tristimulus values or derivatives of these values. A complete color standard definition will usually include painted panels representative of the limits of acceptable deviation from the precise standard color as well.

(Chemical Symbol Cb) - Element No. 41 of the periodic system. Atomic weight 92.91. It is steel gray in color and brilliant luster. Specific gravity 8.57. Melting point at about 4379°F. It is used mainly in the production of stabilized austenitic chromium-nickel steels, also to reduce the air-hardening characteristics in plain chromium steels of the corrosion resistant type.

Commercial Bronze
A copper-zinc alloy (brass) containing 90% copper and 10% zinc; used for screws, wire, hardware, etc. Although termed “commercial-bronze” it contains no tin. It is somewhat stronger than copper and has equal or better ductility.

Commercial Finish
(See Finishes)

Commercial Quality Steel Sheet
Normally to a ladle analysis of carbon limited at 0.15 max. A Standard Quality Carbon Steel Sheet.

Commercial Steel (CS)
Sheet of this quality is for simple bending or moderate forming.  Commercial Steel sheet can be bent flat upon itself in any direction at room temperature
Composite material
A combination of two or more materials (reinforcing elements, fillers, and composite matrix binder), differing in form or composition on a macro scale. The constituents retain their identities, that is, they do not dissolve or merge completely into one another although they act in concert. Normally, the components can be physically identified and exhibit an interface between one another. Examples are cermets and metal-matrix composites.
Concave fillet weld
A fillet weld in which the weld face is concave (curved inwards).
The more luminous part of a flame, which is adjacent to the nozzle orifice.
Constitutional Diagram
A graphical representation of the temperature and composition limits of phase fields in an alloy system as they actually exist under specific conditions of heating and cooling (synonymous with phase diagram). A constitutional diagram may be, or may approximate, and equilibrium diagram, or may represent metastable conditions or phases. Compare equilibrium diagram.
Contact Corrosion
When two dissimilar metals are in contact without a protective barrier between them and they are in the presence of liquid, an electrolytic cell is created. The degree of corrosion is dependent on the area in contact and the electro-potential voltage of the metals concerned. The less noble of the metals is liable to be attacked, i.e. zinc will act as a protector of steel in sea water whereas copper or brass will attack the steel in the same environment.

Market situation when a nearby price is lower than a further forward price.

Continuous Casting
The most popular technique for solidifying steel. Involves pouring steel into an intermediate tundish before entering a water-cooled copper mold. A solidifying steel strand is drawn through a machine where it continues to cool before exiting the machine.
Continuous weld
A weld extending along the entire length of a joint.

Measures the physical use of steel by end users. Steel consumption estimates, unlike steel demand figures, account for changes in inventories.

Apparent Supply
Derived demand for steel using AISI reported steel mill shipments plus Census Bureau reported imports, less Census Bureau reported exports. Domestic market share percentages are based on this figure, which does not take into account any changes in inventory.

Continuous Casting

  • WHAT
     A method of pouring steel directly from the furnace into a billet, bloom, or slab directly from its molten form.
  • WHY
    Continuous casting avoids the need for large, expensive mills for rolling ingots into slabs. Continuous cast slabs also solidify in a few minutes versus several hours for an ingot. Because of this, the chemical composition and mechanical properties are more uniform.
  • HOW
    Steel from the BOF or electric furnace is poured into a tundish (a shallow vessel that looks like a bathtub) atop the continuous caster. As steel carefully flows from the tundish down into the water-cooled copper mold of the caster, it solidifies into a ribbon of red-hot steel. At the bottom of the caster, torches cut the continuously flowing steel to form slabs or blooms.

Continuous Furnace
Furnace, in which the material being heated moves steadily through the furnace.

Continuous Picking
Passing sheet or strip metal continuously through a series of pickling and washing tanks.

Continuous Strip Mill
A series of synchronized rolling mill stands in which coiled flat rolled metal entering the first pass (or stand) moves in a straight line and is continuously reduced in thickness (not width) at each subsequent pass. The finished strip is recoiled upon leaving the final or finishing pass.

Controlled Atmosphere
A gas or mixture of gases in which steel is heated to produce or maintain a specific surface condition. Controlled atmosphere furnaces are widely used in the heat treatment of steel as scaling and decarburization of components is minimized by this process.

Controlled Atmosphere Furnaces
A furnace used for bright annealing into which specially prepared gases are introduced for the purposes of maintaining a neutral atmosphere so that no oxidizing reaction between metal and atmosphere takes place.

Controlled Cooling
A process by which steel is cooled from an elevated temperature in a predetermined manner to avoid hardening, cracking or internal damage, or to produce desired microstructure or mechanical properties.

Controlled Rolling
A hot rolling process in which the temperature of the steel is closely controlled, particularly during the final rolling passes, to produce a fine-grain microstructure.

Conversion Coating
The chemical treatment film applied to the steel or metallic coated sheet prior to painting.

Conversion Cost
Resources spent to process material in a single stage, from one type to another. The costs of converting iron ore to hot metal or pickling hot-rolled coil can be isolated for analysis.

A furnace in which air is blown through the molten bath of crude metal or matte for the purpose of oxidizing impurities.

Demand from steel customers such as re-rollers and tube makers, which process steel into a more finished state, such as pipe, tubing and cold-rolled strip, before selling it to end users. Such steel generally is not sold on contract, making the converter segment of the mills' revenues more price sensitive than their supply contracts to the auto manufacturers.

Convex fillet weld
A fillet weld in which the weld face is convex (bulbous).

Cooling Stresses
Stresses develop by uneven contraction or external constraint of metal during cooling; also those stresses resulting from localized plastic deformation during cooling and retained.

Copper (Cu)
(Chemical symbol Cu) - Element No. 29 of the periodic system, atomic weight 63.57. A characteristically reddish metal of bright luster, highly malleable and ductile and having high electrical and heat conductivity; melting point 1981°F.; boiling point 4237°F.; specific gravity 8.94. Universally used in the pure state as sheet, tube, rod and wire and also as alloyed by other elements (See Brass and Bronze), as an alloy with other metals.

In the case of steel this refers to a component that has been case-hardened where the centre is softer than the hard surface layer or case. It can also be applied to the central part of a rolled rimming steel.

Core Wound Flat Wire
(See Oscillated Wound Coils)

  • WHAT
    Corex is a coal-based smelting process that yields hot metal or pig iron. Integrated mills or EAF mills can use the output.

  • HOW
    The process gasifies non-coking coal in a smelting reactor, which also produces liquid iron. The gasified coal is fed into a shaft furnace, where it removes oxygen from iron ore lumps, pellets or sinter; the reduced iron is then fed to the smelting reactor.

A variation of composition between the center and surface of a unit of structure (such as a dendrite, a grain or a carbide particle) resulting from non-equilibrium growth over a range of temperature.

The gradual degradation or alteration of steel caused by atmosphere, moisture, or other agents.

If mild steel is exposed to an aerated neutral aqueous solution, for example a dilute solution of sodium chloride in water, then corrosive attack will begin at defects in the oxide film on the steel. These defects may be present as a result of mechanical damage such as scratches, or may be due to natural discontinuities in the film, i.e. inclusions, grain boundaries or dislocation networks at the surface of the steel.
At each defect the steel is exposed to the solution (electrolyte) and an anodic reaction occurs, resulting in the formation of iron ions and free electrons. These electrons are then conducted through the oxide film to take part in a cathodic reaction at the surface of the film. This reaction requires the presence of dissolved oxygen in the electrolyte and results in the formation of hydroxyl ions.

The hydroxyl ions react with the ferrous ions produced by the anodic reaction to form ferrous hydroxide, which is then converted into a hydrated oxide called, ?rust'. Gradually a scab of rust may form over the top of the pit, but this is too porous to completely block the anodic area. This allows the corrosion process to continue, resulting in deeper attack and widening of the anodic area as the surface oxide film breaks away.

If the pH of the solution in contact with the steel is low, for example a dilute acid, then the surface oxide film will be removed and the cathodic reaction will be different. Hydrogen gas will be liberated as gradual dissolution of the steel occurs. With oxidizing acids, a number of alternate cathodic reactions may take place.
In all cases of corrosion the anodic reaction cannot proceed in isolation from the cathodic reaction and if either reaction can be limited or stopped then less or no corrosion will occur.

Corrosion Embrittlement
The embrittlement caused in certain alloys by exposure to a corrosive environment. Such material is usually susceptible to the intergranular type of corrosion attack.

Corrosion Fatigue
Fatigue that arises when alternating or repeated stress combines with corrosion. The severity of the action depends on the range and frequency of the stress, the nature of the corroding condition and the time under stress.

As a defect. Alternate ridges and furrows. A series of deep short waves.

Coupon plate
A test piece made by adding plates to the end of a joint to give an extension of the weld for test purposes. (Note: this term is usually used in the shipbuilding industry.)

Covered Electrode
A filler-metal electrode, used in arc welding, consisting of a metal core vire with a relatively thick covering which provides protection for the molten metal form the atmosphere, improves the properties of the weld metal and stabilizes the arc. The covering is usually mineral or metal powders mixed with cellulose or other binder.

Chemical symbol for Chromium.

A longitudinal discontinuity produced by fracture. Cracks may be longitudinal, transverse, edge, crater, centre line, fusion zone underhead, weld metal or parent metal

Crater pipe
A depression due to shrinkage at the end of a run where the source of heat was removed.

The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength. The effect is particularly important if the temperature of stressing is above the re-crystallization temperature of the metal.

Creep Limit
(1) The maximum stress that will cause less than a specified quantity of creep in a given time.
(2) The maximum nominal stress under which the creep strain rate decreases continuously with time under constant load and at constant temperature. Sometimes used synonymously with creep strength.

Creep Strength
(1) The constant nominal stress that will cause a specified quantity of creep in a given time at constant temperature.
(2) The constant nominal stress that will cause a specified creep react at constant temperature.

Crevice Corrosion
Corrosion of a metal surface that is fully shielded from the environment but corrodes because it is so close to the surface of another metal.

Critical Cooling Rate
The minimum rate of continuous cooling just sufficient to prevent undesired transformations. For steel, the slowest rate at which it can be cooled form above the upper critical temperature to prevent the decomposition of austenite at any temperature above the Ms.

Critical Point
(1) The temperature or pressure at which a change in crystal structure, phase or physical properties occurs; same as transformation temperature. (2) In an equilibrium diagram, that specific combination of composition, temperature and pressure at which the phases of an inhomogeneous system are in equilibrium.

Critical Range
A temperature range in which an internal change takes place within a metal. Also termed Transformation Range.
Critical Temperature
The temperature at which some phase change occurs in a metal during heating or cooling, i.e. the temperature at which an arrest or critical point is shown on heating or cooling curves.

Critical Surface
Intended for material applied to critical exposed/painted applications where cosmetic surface imperfections are objectionable. The prime side surface will be free of repetitive type imperfections, gouges, scratches, scale and slivers. This surface can only be furnished as a pickled product.
The defective ends of a rolled or forged product which are cut off and discarded.
Cropped Head/Tail
Squaring of the strip by use of mechanical shear.
Cutting off ends of billets ingots or slabs containing pipe or other defects.
Deviation from flat across the strip width

Cross Break
(See Luders Lines) This term also applies to transverse ribs or ripples.

Cross Direction
(In rolled or drawn metal) The direction parallel to the axis of the rolls during rolling. The direction at, right angles to the direction of rolling or drawing.

Cross Rolling
Rolling at an angle to the long dimension of the metal; usually done to increase width.

Crown or Heavy Center
Increased thickness in the center of metal sheet or strip as compared with thickness at the edge.

A ceramic pot or receptacle made of graphite and clay, or other refractory materials, and used in the melting of metal. The term is sometimes applied to pots made of cast iron, cast steel or wrought steel.

Crucible Steel
High-carbon steel produced by melting blister steel in a covered crucible. Crucible steel was developed by Benjamin Huntsman in about 1750 and remained in use until the late 1940's.

Cruciform test piece
A flat plate to which two other flat plates or two bars are welded at right angles and on the same axis.

Crude steel
Steel in the first solid state after melting, suitable for further processing or for sale. Synonymous to raw steel.

Cryogenic applications
Sub-zero temperature applications


(1) A physically homogeneous solid, in which the atoms , ions, or molecules are arranged in a three-dimensional repetitive pattern.
(2) A coherent piece of matter, all parts of which have the same anisotropic arrangement of atoms; in metals, usually synonymous with “grain” and “crystallite.”

Composed of crystals.

Crystalline Fracture
A type of fracture that appears bright and glittering, it having formed along the cleavage planes of the individual crystals. Normally an indication that brittle fracture has occurred.

The formation of crystals by the atoms assuming definite positions in a crystal lattice. This is what happens when a liquid metal solidifies. (Fatigue, the failure of metals under repeated stresses, is sometimes falsely attributed to crystallization.)

Chemical symbol for Copper.

Metallography - (Concerning space lattices) - Body-centered cubic. Refers to crystal structure.

Cup Fracture
A type of fracture in a tensile test specimen which looks like a cup having the exterior portion extended with the interior slightly depressed.

The fracture of severely worked rods or wire where one end has the appearance of a cup and the other that of a cone.

Cut Edge
Removal of the as-rolled hot mill edge. Coil ends are cropped back to gauge when cut edge is ordered.

Cup Test
(See Olsen Ductility Test)

Culvert Pipe
Heavy gauge, galvanized steel that is spiral-formed or riveted into corrugated pipe, which is used for highway drainage applications.

Custom Smelter
A smelter that processes concentrates for customers rather than a feed from its own mining operation. For this service treatment charges or tolling charges are received.

Cut Wire Shot
is a product used for Shot Peening and Blasting. Provided in range from Dia 0.40mm to 2.00mm. Used by Manufacturers of Leaf Spring, etc. Available in materials like Steel, SS, Aluminium etc.,

Process to uncoil sections of flat-rolled steel and cut them into a desired length. Product that is cut to length is normally shipped flat-stacked.

Cutting electrode
An electrode with a covering that aids the production of such an arc that molten metal is blown away to produce a groove or cut in the work.

Cutting oxygen
Oxygen used at a pressure suitable for cutting.

Cutting Speed
The linear or peripheral speed of relative motion between the tool and work piece in the principal direction of cutting.

Cyanide Hardening
A process of introducing carbon and nitrogen into the surface of steel by heating it to a suitable temperature in a molten bath of sodium cyanide, or a mixture of sodium and potassium cyanide, diluted with sodium carbonate and quenching in oil or water. This process is used where a thin case and high hardness are required.

Surface hardening of an iron-base alloy article or portion of it by heating at a suitable temperature in contact with a cyanide salt, followed by quenching.