Glossary

Camber

When sheet or strip is rolled, it is not exactly straight from end to end. If a coil was unrolled along an absolutely straight stretch of highway, it would be found to wander from side to side or in some cases, run off the road completely. This deflection to the left and right is called camber. It is measured as the amount of left or right deflection in 8-feet. As it relates to plates is the horizontal edge curvature in the length, measured over the entire length of the plate in the flat position.

Canning

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

Carbide

A compound of carbon with one or more metallic elements.

Carbide Precipitation:

In 300 series stainless steel, Chromium reacts with Carbon in the temperature range of 800° to 1500°F causing “sensitization”. This reaction is generally considered to be detrimental to corrosion resistance because of the Chromium content decrease in the grain area adjacent to the grain boundaries.

Carbon Steels

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. It is classified as carbon steel when the maximum content does not exceed the following percentages

Carburizing

A process in which an austenitized ferrous material is brought into contact with a carbonaceous atmosphere having sufficient carbon potential to cause absorption of carbon at the surface and, by diffusion, create a concentration gradient.

Cast Iron

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

Casting

(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.

Centrifugal Casting

A casting made by pouring metal into a mold that is rotated or revolved.

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.

Chatter

Surface condition characterized by a series of close spaced lines across the strip width; generally caused by vibration in the mill rolls.

Chemical Content or Analysis

A breakdown of elements present by percent of weight in metals or alloys. Although the ladle analysis is certified at the time of melting, additional analyses may be performed throughout the steel producing process.

Chemical Milling

Removing metal stock by controlled selective chemical etching.

Chromium

Chemical symbol Cr. Element No. 24 of the periodic system; atomic weight 52.01. It is of bright silvery color, relatively hard. It is strongly resistant to atmospheric and other oxidation. It is of great value in the manufacture of Stainless Steel as an iron-base alloy. Chromium plating has also become a large outlet for the metal. Its principal functions as an alloy in steel making; (1) increases resistance to corrosion and oxidation (2) increases harden-ability (3) adds some strength at high temperatures (4) resists abrasion and wear (with high carbon).

Chromium Carbide

One of a number of compounds of chromium and carbon, with or without limited amounts of other metallic elements when occurring in steel, appearing as separated phase in chromium steels and stainless steels.

Chromizing

A surface treatment at elevated temperature, generally carried out in pack, vapor, or salt bath, in which an alloy is formed by the inward diffusion of chromium into the base metal.

Classification of Stainless Steels

Stainless steels are classified into five distinct groups, namely

Cluster Mill

A rolling mill where each of the two working rolls of small diameter is supported by two or more back-up rolls.

Cobalt

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.; 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.

Coil Breaks

Surface condition characterized by a series of wide spaced lines generally caused by reels used in uncoiling.

Coil Set

Almost all coils will display coil set when unbanded, except for very thin or very soft material. Because most coils are delivered with inside diameters of less than two feet, coil set resulting from bending to these diameters will be introduced even if the coil was “dead-flat” before recoiling at the mill or slitter. Mill capability is 6″ maximum in a 3-foot length.

Coining

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

Cold Reduced Strip

Metal strip, produced from hot-rolled strip, by rolling on a cold reduction mill.

Cold Working

Plastic deformation, such as rolling, hammering, drawing, etc., at a temperature sufficiently low to create strain-hardening (work-hardening). Commonly, the term refers to such deformation at normal temperatures.

Concast/continuous casting method

Concast is an abbreviation for continuous cast, a molding process developed as an alternative to the ingot casting method. In continuous casting, the mold is made of copper and is water-cooled to remove heat from the molten steel. As the metal passes through the water-cooled mold, it forms a solid shell on the outside while the inside is still full of liquid steel. This shell passes out the bottom of the copper mold and into a spray chamber where water is directed against it, removing more and more of the heat from the steel and causing it to solidify from the edge toward the center until it is completely solidified. This solidified slab passes out upon a roller conveyor where it is cut to the lengths desired for hot rolling.

Conditioning

The removal of surface defects (seams, laps, pits, etc.).

Continuous Annealing

The process where coils are unwound and run continuously through an annealing furnace at prescribed speeds and softening temperatures.

Continuous Pickling

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 Furnaces

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

Cores

Cores are thick cardboard sleeves that hold light gauges coils in the same way that thin cardboard sleeves hold Aluminum wrap in your home. The cardboard used with steels is about 3/4 inch thick and is extremely strong. Light-gauge material is frequently wrapped onto cores to prevent the coils from collapsing in transit. The use of cores also prevents damage to the wraps on the inside diameter by crane hooks or fork truck forks.

Corrosion

Destruction of metal by chemical or electrochemical reaction with its environment; simply said, “eating away of metals”.

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

Cracking produced by the combined action of repeated or fluctuating stress and a corrosive environment.

Corrosion Resistance

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

Corrosion Resistance Alloys

These are materials which provide a higher degree of stress corrosion and/or chloride pitting resistance than that of common types 2XX, 3XX, or 4XX stainless steels. Corrosion resistant alloys are generally characterized by chrome content of at least 20% and/or moly content greater than 2%.

Coupon

A piece of metal from which a test specimen is to be prepared – often an extra piece (as on a casting or forging) or a separate piece made for test purposes (such as a test weldment).

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 value of composition, temperature and pressure, or combinations thereof, at which the phases of a heterogeneous systems are in equilibrium.

Cropping

Cutting off ends of billets ingots or slabs containing pipe or other defects.

Cross Country Mill

A mill composed of several stands which are arranged in train or in two or more trains so that the piece being rolled reverses direction of travel two or more times before the finish. The trains of rolls are so far apart that the bar is engaged in only one stand at a time.

Cross Rolling

The rolling of sheet, plate or slabs so that the direction of rolling is changed 90 degrees from the direction of the previous rolling

Crossbow

Deviation from flat across the strip width.

Crown

Edge to edge thickness variation in flat rolled products. Crown is generally a smooth curve from the center of mill coil to within a few inches of the edge where thickness starts to drop or “feather” more rapidly. In narrow slit coils, crown will appear as a variation in thickness from coil to coil. On a half width slit coil or “split”, wedged shaped cross sections occur, thicker on one side than on the other. .

Crucible

A ceramic pot or receptacle made of graphite and clay, or clay or other refractory material, 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.

Cryogenic

Sub-zero temperature applications.

Crystal

(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 atom; in metals, usually synonymous with grain and crystallite.

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.

Cupping

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