Glossary of Metal Terms

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

CADMIUM

 

Chemical symbol Cd. Cadmium is produced primarily as a by-product of zinc refining, but also is recovered during the beneficiation and refining of some lead ores and complex copper-zinc ores. Cadmium is bluish-white soft metal that can be cut with a knife. The principal use of cadmium, which was discovered in Germany in 1817, has been in nickel-cadmium batteries for personal, portable communications, electronic and electrical equipment. Other applications include pigments, coatings and plating, stabilizers for plastics and similar synthetics, alloys, lasers, and solar cells.  

CAMBER OR BOW

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

CARBIDE

A compound of carbon with one or more metallic elements.

CARBON STEEL

Ordinary steel made by melting iron or ferrous scrap with carbon, manganese, sulfur, silicon, and phosphorous (see STEEL).

CARBURIZING

(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.

CASING

The structural steel retainer for the walls of oil and gas wells, and accounts for 75% (by weight) of the shipments of all oil country tubular goods (see OCTG). 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.

CASTING

The forming of molten metal into a particular shape by pouring the molten material into a precisely shaped mold or die. There are several casting processes used in making iron and steel shapes (green sand, dry sand, shell mold, core mold, permanent mold, ceramic mold, expandable pattern, centrifugal, continuous and die casting) with the die casting process the most popular method of casting non-ferrous metals (primarily zinc, aluminum, and magnesium and less often copper, tin, and lead).

CATHODE

Primary non-ferrous metal casting to be rolled or forged into other shapes; usually copper or nickel.

CESIUM

Chemical symbol Cs. A silvery-white metal refined from pollucite ore, usually as a co-product in the processing of titanium, beryllium, or lithium minerals. Cesium ignites when exposed to air; has a 28.5-degree F melting point; used in making specialized energy converters and electric power generators.

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.

CHIPPING

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.”

CHROMIUM

Chemical symbol CR. An alloying element that is the essential raw material for conferring corrosion resistance in stainless steel. A film that naturally forms on the surface of chromium-bearing stainless steel self-repairs in the presence of oxygen if the steel is damaged mechanically or chemically; thus, preventing corrosion.

CLADDING

The method of bonding one metal atop another metal; this increases corrosion resistance for steel, galvanic protection for aluminum, electrical conductivity for copper, etc.

CLUSTER MILL

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

COATED METALS

Sheet and strip steel or aluminum, usually in coil form, which has been covered on one or both sides with paint, enamel, adhesive, anti-corrosive coatings, and/or laminates.

COBALT

Chemical symbol Co. Gray magnetic metal of medium hardness with good corrosion resistance. Used as matrix metal in most cemented carbides. Principal function is for alloying in tool steels or superalloys because of its ability to harden ferrite (iron).

COBALT-BASED SUPERALLOYS

Eight specific alloys of at least 50% cobalt blended with traces of such other metals as iron, nickel, chrome, titanium, tungsten, carbon, zirconium, and/or tantalum; used in high-temperature, high-strength, anti-corrosion applications (such as aircraft gas turbines and jet engine components).

COIL

Sheet metal rolled from slab or ingot that, then, has been wound. Once rolled in a hot-strip mill, a steel coil is more than one-quarter mile long. Coils are the most efficient way to store and transport sheet metal.

COIL SET 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 WELD

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

COINING

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

COLD-REDUCING (COLD-ROLLING)

Rolling of cooled metal sheet (or other form which previously has been hot-rolled) to make the steel thinner, smoother, and stronger, by applying pressure. A cold-reduction sheet mill, for example, will roll-press a sheet of metal from one-quarter inch thick into less than an eighth of an inch, while more than doubling its length.

COLD-ROLLED SHEET (AND STRIP)

Sheet of steel, aluminum, copper, or alloy that has passed a cold-reduction mill to give a relatively smooth appearance. 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.

COLD-FINISHED STEEL BARS

Hot-rolled carbon steel bars after secondary cold-reduction processing with better surface quality and strength.

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.

COLD-WORKING

Rolling, hammering, or stretching metal at a low temperature (often room temperature) to create a permanent increase in the hardness and strength by making changes in the metallurgical structure and shape of the metal.

COLUMBIUM

Chemical symbol Co. Refractory metal used as an alloying agent in steel making; essential for high-strength, low-alloy grades. Has some "worked metal" applications, mostly alloyed with zirconium or titanium for aerospace applications. Called Niobium (Nb) everywhere but the U.S.

COPPER

Chemical symbol Cu. A characteristically reddish metal of bright luster; highly malleable and ductile; high heat conductivity; an excellent conductor of electricity and is celebrated for its corrosion resistance. Copper is believed to have been discovered around 8,000 B.C. near the site of a village in the valleys of the Tigris and Euphrates rivers in what is now Iraq. Deposits in Egypt were worked as early as 5,000 B.C. The word copper is derived from "Cyprus," and substantial quantities of the metal were mined on that Mediterranean island. Used in the pure state or alloyed by other elements to make brasses and bronzes consumed in building construction, electric and electronic products, industrial machinery, transportation equipment, and numerous consumer and general products. Copper also is alloy with other metals as nickel (creating cupro-nickel) and beryllium.

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.

CORROSION

Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents.

CROP

The defective ends of a rolled or forged product which are cut off and discarded.

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.

CULVERT PIPE

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

CUTTING-TO-LENGTH (LENGTH-CUTTING)

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Uncoil sections of flat-rolled metal, and then cutting them into a desired length. Product that is cut to length is normally shipped flat-stacked.

DEBURRING

Removal of the very subtle ridge on the edge of strip metal left by such cutting operations as slitting, trimming, shearing, or blanking. (See EDGE-ROLLING)

DEEP DRAWING

The process of cold working or drawing sheet or strip metal blanks by means of dies on a press into shames which are usually more or less cup-like in character involving considerable plastic deformation of the metal. Deep-drawing quality sheet or strip steel, ordered or sold on the basis of suitability for deep-drawing.

DIE CASTING

The principal process for casting near-net shapes of such non-ferrous metals as zinc, aluminum, and zinc-aluminum alloy (see CASTING).

DIE-LINES

Lines of markings caused on drawn or extruded products by minor imperfections in the surface of the die.

DIE SINKING

Forming or machining a depressed pattern in a die.

DIRECT-REDUCED IRON (DRI)

A metallic iron product made from iron ore pellets, lumps or fines that is reduced (by removing only the oxygen) from the ore at a temperature below the melting point of the iron. DRI is used as feedstock in electric-arc furnaces, blast furnaces and in other iron and steel making processes.

DISTRIBUTOR

(See SERVICE CENTER)

DRAWN-OVER-MANDREL

A procedure for producing specialty DOM tubing using a drawbench to pull tubing through a die and over a mandrel, giving excellent control over the inside diameter and wall thickness. Advantages of this technique are its inside and outside surface quality and gauge tolerance. Major markets include automotive applications and hydraulic cylinders.

DRILL PIPE

Pipe used in the drilling of an oil or gas well. Drill pipe is the conduit between the wellhead motor and the drill bit. Drilling mud is pumped down the center of the pipe during drilling, to lubricate the drill bit and transmit the drilled core to the surface. Because of the high stress, torque and temperature associated with well drilling, drill pipe is a seamless product.

DRY ROLLED FINISH

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Finish obtained by cold rolling on polished rolls without the use of any coolant or metal lubricant, material previously plain pickled, giving a burnished appearance.

EDGES

Many types of edges can be produced in the manufacture of flat rolled metal products. Over the years the following types of edges have become recognized as standard in their respective fields.

COPPER BASE ALLOYS

Slit, Slit and Edge Rolled, Sheared, Sawed, Machined or Drawn,

SHEET STEELS OR ALUMINUM SHEET

Mill Edge, Slit Edge or Sheared Edge.

STRIP STEELS and STAINLESS STRIP

No. 1 Edge - A smooth, uniform, round or square edge, either slit or filed or slit and edge rolled as specified, width tolerance +/-.005”.

No. 2 Edge - A natural round mill edge carried through from the hot rolled band. Has not been slit, filed, or edge rolled. Tolerances not closer than hot-rolled strip limits.

No. 3 Edge - Square, produced by slitting only. Not filed. Width tolerance close.

No. 4 Edge - A round edge produced by edge rolling either from a natural mill edge or from slit edge strip. Not as perfect as No. 1 edge. Width tolerances liberal.

No. 5 Edge - An approximately square edge produced by slitting and filing or slitting and rolling to remove burr.

No. 6 Edge - A square edge produced by square edge rolling, generally from square edge hot-rolled occasionally from slit strip. Width tolerances and finish not as exacting as No. 1 edge.

EDGE-CONDITIONING (EDGE-ROLLING)

Rolling a strip of metal to smooth the edges. By removing the burr off the coil, it is safer for users to manipulate during transport, storage, and processing. (See DEBURRING)

EDGE FILING

A method whereby the raw or slit edges of strip metal are passed or drawn one or more times against a series of files, mounted at various angles. This method may be used for deburring only or filing to a specific contour including a completely rounded edge.

EDGE STRAIN OR EDGE BREAKS

Creases extending in from the edge of the temper rolled sheet.

ELASTIC LIMIT

Maximum stress that a material will stand before permanent deformation occurs.

ELECTRIC-RESISTANCE WELDED PIPE

ERW pipe is made from strips of hot-rolled steel, which are passed through forming rolls and welded. While seamless pipe is traditionally stronger and more expensive than ERW pipe, ERW technology is improving and the technique now accounts for approximately 48% of annual tonnage shipments of oil country tubular goods (see OCTG).

ELECTRICAL STEEL

(See SILICON ELECTRICAL STEEL)

ELECTROGALVANIZED

Electrolytic-deposition zinc-plating process whereby the molecules on the positively charged zinc anode attach to the negatively charged steel (usually in sheet form). The thickness of the zinc coating is readily controlled; by increasing the electric charge or slowing the speed of the steel through the plating area, the coating will thicken on the metal substrate.

EMBOSSED ALUMINUM

Flat-rolled aluminum with a surface appearance that has a stucco or grained look.

ETCHING

In metallography, the process of revealing structural details by the preferential attack of reagents on a metal surface.

EXPANDED METAL

A rigid, non-raveling metal sheet or plate of carbon or stainless steel, aluminum, and a variety of alloys of copper, nickel, silver, and titanium that has been slit and expanded (drawn) into an open mesh pattern that is stronger, lighter in weight, and more rigid than the original material.

EXTRUSION

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A shaped piece of metal (typically nonferrous), produced by forcing the bloom, bar, or rod through a die of appropriate shape.

FABRICATOR

A producer of intermediate products that does not also produce primary metal. Examples include brass, wire and rod mills, which buy copper and other primary or secondary metals to produce brass and other copper alloys, or take raw forms of metal and make building, magnet, telecommunications and/or industrial wire, rod, and similar products.

FERRALLOY

A metal product commonly used as a raw material feed in steel making, usually containing iron and other metals to aid various stages of the steel making process such as deoxidation, desulfurization and adding strength. Examples: ferrochrome, ferromanganese and ferrosilicon.

FLAT-ROLLED STEEL

Steel processed on rolls with flat faces as opposed to grooved or cut faces. Flat-rolled products include sheet, strip and tin plate, among others.

FERROUS

Related to iron; derived from the Latin, ferrum. Ferrous metals are, therefore, iron-based metals.

FIBER OR FIBRE

Direction in which metals have been caused to flow, as by rolling, with microscopic evidence in the form of fibrous appearance in the direction of flow.

FILED EDGES

Finished edges, the final contours of which are produced by drawing the strip over a series of small steel files. This is the usual and accepted method of dressing the edges of annealed spring steel strip after slitting in cases where edgewise slitting cracks are objectionable or slitting burr is to be removed.

FINISHES

The surface appearance of the various metals after final treatment such as rolling, etc. Over the years the following finishes have become recognized as standard in their respective fields.

ALUMINUM SHEET

(A) Commercially Bright.

(B) Bright one side.

(A) Bright both sides

(D) Embossed Sheets (Produced by using embossed rolls.)

BLACK PLATE

(A) Dull finish without luster produced by use of roughened rolls.

(B) Bright finish - a luster finish produced by use of rolls having a moderately smooth surface.

COLD ROLLED STEEL SHEETS

(A) Commercial Finish. A dull satin surface texture produced by roughened rolls.

(B) Commercial Bright Finish. Bright in appearance with a texture between luster and a very fine matte finish.

(C) Luster Finish. Produced by use of ground and polished rolls. (Note: This is not a number 3 finish.)

COLD ROLLED STRIP STEELS

No. 1 Finish - A dull finish produced without luster by rolling on roughened rolls.

No. 2 Finish - A regular bright finish produced by rolling on moderately bright rolls.

No. 3 Finish - Best Bright Finish. A lustrous or high gloss finish produced by rolling on highly polished rolls. Also referred to as “Mirror Finish”.

COPPER BASE ALLOYS

Acid Dipped - Dry rolled finished. Produced by dry cold rolling bi-chromate dipped alloy with polished rolls, resulting in a burnished appearance and retaining the color obtained by dipping (True Metal Color).

Bright Dipped Finish - Finish resulting from an acid dip.

Buffed or Polished Surface - A finish obtained by buffing, resulting in a high gloss or polished finish.

Cold Rolled Finish - A relatively smooth finish obtained by cold rolling plain pickled strip with a lubricant.

Dry Rolled Finish - A burnished finish resulting from dry cold rolling by use of polished rolls without any metal lubricant.

Hot Rolled Finish - A dark relatively rough oxidized finish resulting from rolling the metal while hot. May subsequently be pickled or bright dipped but the rough surface remains.

Stretched Brushed Finish (Satin Finish) Obtained by mechanically brushing with wire brushes or by buffing.

FLAT WIRE

No. 2 Finish - A regular bright finish.

No. 3 Finish - Best Bright High Gloss finish produced by use of polished rolls. Or by special buffing - this is a negotiated finish.

STAINLESS COLD ROLLED SHEET and STRIP Nos. 1, 2B & 2D.

No. 1 Finish - C. R. Annealed and pickled appearance varies from dull gray matte finish to a fairly reflective surface.

No. 2B Finish - Same as No.1 Finish followed by a final light cold rolled pass generally on highly polished rolls.

No. 2D Finish - A dull cold rolled finish produced by cold rolling on dull rolls.

STAINLESS C.R. SHEET - Polished Finishes

No. 3 Finish - This is an intermediate polished finish.

No. 4 Finish - Ground and Polished finish.

No. 6 Finish - Ground, Polished and Tampico Brushed.

No. 7 Finish - Ground and High Luster Polished.

No. 8 Finish - Ground and Polished to Mirror Finish.

TEMPERED and UNTEMPERED COLD ROLLED CARBON SPRING

STEEL STRIP

Classified by description as follows:

(A) Black Oil Tempered.

(B) Scaleless Tempered.

(A) Bright Tempered.

(D) Tempered and Polished.

(E) Tempered, Polished and Colored (Blue or Straw).

TIN PLATE

(A) Bright Hot Dipped Finish.

(B) Electro Matte Dull Finish.

(C) Electro Bright Reflow Finish - produced by the in-the-line thermal treatment following electrodeposition.

FLOOR PLATE

Usually carbon (but also alloy and stainless) steel plate rolled with raised lug patterns to provide traction for feet and wheels; as the name suggests, used widely for flooring.

FLUTING

Kinking or breakage due to curving of metal strip on a radius so small, with relation to thickness, as to stretch the outer surface above its elastic limit. Not to be confused with the specific product, Fluted Tubes.

FOIL

Metal in any width but no more than about 0.005-inch thick.

FORGING

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The working of metal to some predetermined shape by hammering, upsetting, pressing, or rolling (or a combination of these processes); the metal can be hot or cold. The most common metals forged include carbon, alloy and stainless steels; very hard tool steels; aluminum; titanium; brass and copper; and high-temperature alloys containing cobalt, nickel, or molybdenum. There are four principal types of commercial forgings: drop forgings, where the shape has been formed by repeated blows by a hammer onto a bar or bullet placed between a pair of dies; upset forgings, where the cross-sectional area is increased while the thickness is decreased; roll forgings, whereby the shaping is done by two rotating rolls; and press forgings, where hydraulic pressure deforms the metal.