Backer Coat
Usually refers to the coating on the reverse side of a pre-painted sheet. The backer coating is generally not as narrowly specified with reference to its color, thickness and composition as is the topcoat.
Retrogression of the flame into the blowpipe neck or body with rapid self extinction.
Backing bar
A piece of metal or other material placed at a root (Temporary backing) (These terms are applied only to the welding of pipes or tubes.)
Back-step sequence
A welding sequence in which short lengths of run are (Back-step sequence)
Backing strip
A piece of metal placed at a root and penetrated by (Permanent backing)

A slender, needle-like (acicular) microstructure appearing in spring steel strip characterized by toughness and greater ductility than tempered Martensite. Bainite is a decomposition product of Austenite (see Austenite) best developed at interrupted holding temperatures below those forming fine pearlite and above those giving Martensite. 

Band Saw Steel (Wood)
A hardened tempered bright polished high carbon cold rolled spring steel strip produced especially for use in the manufacture of band saws for sawing wood, non ferrous metals, and plastics. Usually carries some nickel and with a Rockwell value of approximately C40/45.

Banded Structure
Appearance of a metal, under a microscope or viewed by the naked eye, on fractured or smoothed surfaces, with or without etching, showing parallel bands in the direction of rolling or working. 

Surface of metal, under the oxide-scale layer, resulting from heating in an oxidizing environment. In the case of steel, such bark always suffers from decarburization.

Long steel products that are rolled from billets. Merchant bar and reinforcing bar (rebar) are two common categories of bars, where merchants include rounds, flats, angles, squares, and channels that are used by fabricators to manufacture a wide variety of products such as furniture, stair railings, and farm equipment. Rebar is used to strengthen concrete in highways, bridges and buildings.

Basic Oxygen Furnace (BOF)
  • WHAT
    A pear-shaped furnace, lined with refractory bricks, that refines molten iron from the blast furnace and scrap into steel. Up to 30% of the charge into the BOF can be scrap, with hot metal accounting for the rest.

  • WHY
    BOFs, which can refine a heat (batch) of steel in less than 45 minutes, replaced open-hearth furnaces in the 1950s; the latter required five to six hours to process the metal. The BOF's rapid operation, lower cost and ease of control give it a distinct advantage over previous methods.
  • HOW
    Scrap is dumped into the furnace vessel, followed by the hot metal from the blast furnace. A lance is lowered from above, through which blows a high-pressure stream of oxygen to cause chemical reactions that separate impurities as fumes or slag. Once refined, the liquid steel and slag are poured into separate containers.

Basic Open Hearth
(See Open-Hearth Process)

Basic Oxygen Process
A steel making process wherein oxygen of the highest purity is blown onto the surface of a bath of molten iron contained in a basic lined and ladle shaped vessel. The melting cycle duration is extremely short with quality comparable to Open Hearth Steel.

Basic Process
A steel making process either Bessemer, open hearth or electric, in which the furnace is lined with a basic refractory. A slag, rich in lime, being formed and phosphorous removed.

Basic Steel
Steel melted in a furnace with a basic bottom and lining and under a slag containing an excess of a basic substance such as magnesia or lime.

Bessemer Process
A process for making steel by blowing air through molten pig iron contained in a refractory lined vessel so that the impurities are thus removed by oxidation.

Bath Annealing
Immersion in a liquid bath (such as molten lead or fused salts) held at an assigned temperature. When a lead bath is used, the process is known as lead annealing.

The only commercial ore of aluminum, corresponding essentially to the formula Al2O3xH2O.

Raising a ridge on sheet metal.

Bearing Load
A compressive load supported by a member, usually a tube or collar, along a line where contact is made with a pin, rivet, axle, or shaft.

Bearing Strength
The maximum bearing load at failure divided by the effective bearing area. In a pinned or riveted joint, the iffective area is calculated as the product of the diameter of the hole and the thickness of the bearing member

Belly Band
The band (strapping) that goes around the outside diameter of a coil.

Bend Radius
The inside radius of a bent section,

Bend Text
Various tests used to determine the toughness and ductility of flat rolled metal sheet, strip or plate, in which the material is bent around its axis or around an outside radius. A complete test might specify such a bend to be both with and against the direction of grain. For testing, samples should be edge filed to remove burrs and any edgewise cracks resulting from slitting or shearing. If a vice is to be used then line the jaws with some soft metal or brass, so as to permit a free flow of the metal in the sample being tested.

Beryllium Copper
An alloy of copper and 2-3% beryllium with optionally fractional percentages of nickel or cobalt. Alloys of this series show remarkable age-hardening properties and an ultimate hardness of about 400 Brinell (Rockwell C43). Because of such hardness and good electrical conductivity, beryllium-copper is used in electrical switches, springs, etc.

Refers to pipe; the end preparation for field welding of the joint.

A semi-finished steel form that is used for "long" products: bars, channels or other structural shapes. A billet is different from a slab because of its outer dimensions; billets are normally two to seven inches square, while slabs are 30-80 inches wide and 2-10 inches thick. Both shapes are generally continually cast, but they may differ greatly in their chemistry.

Binary Alloy
An alloy containing two elements, apart from minor impurities, as brass containing the two elements copper and zinc.

Black Annealing
A process of box annealing or pot annealing ferrous alloy sheet, strip or wire after hot working and pickling. (See Box Annealing)

Black Oil Tempered Spring Steel Strip (Scale less Blue)
A flat cold rolled usually .70/.80 medium high carbon steel strip, blue-black in color, which has been quenched in oil and drawn to desired hardness. While it looks and acts much like blue tempered spring steel and carries a Rockwell hardness of C44/47, it has not been polished and is lower in carbon content. Used for less exacting requirements than clock spring steel, such as snaps, lock springs, hold down springs, trap springs, etc. It will take a more severe bend before fracture than will clock spring, but it does not have the same degree of spring-back.

Black Plate
Cold-reduced sheet steel, 12-32 inches wide, that serves as the substrate (raw material) to be coated in the tin mill.

An early step in preparing flat-rolled steel for use by an end user. A blank is a section of sheet that has the same outer dimensions as a specified part (such as a car door or hood) but that has not yet been stamped. Steel processors may offer blanking for their customers to reduce their labor and transportation costs; excess steel can be trimmed prior to shipment.

Blast Box
(See Tin Plate Base Box)

Blast Furnace
A towering cylinder lined with heat-resistant (refractory) bricks, used by integrated steel mills to smelt iron from its ore. Its name comes from the "blast" of hot air and gases forced up through the iron ore, coke and limestone that load the furnace.

A defect in metal produced by gas bubbles either on the surface or formed beneath the surface while the metal is hot or plastic. Very fine blisters are called “pin-head” or “pepper” blisters.

Blister Steel
High-carbon steel produced by carburizing wrought iron. The bar, originally smooth, is covered with small blisters when removed from the cementation (carburizing) furnace.

Block sequence
A welding sequence in which short lengths of the (Block welding)

A semi-finished steel form whose rectangular cross-section is more than eight inches. This large cast steel shape is broken down in the mill to produce the familiar I-beams, H-beams and sheet piling. Blooms are also part of the high-quality bar manufacturing process: Reduction of a bloom to a much smaller cross-section can improve the quality of the metal.

A mill used to reduce ingots to blooms, billets, slabs, sheet-bar etc. (See Semi-Finished Steel)

A device for mixing and burning gases to produce a flame for welding, brazing, bronze welding, cutting, heating and similar operations.

A cavity produced during the solidification of metal by evolved gas, which in failing to escape is held in pockets.

Blue Annealing
A process of softening ferrous alloys in the form of hot rolled sheet, by heating in the open furnace to a temperature within the transformation range and then cooling in air. The formation of bluish oxide on the surface is incidental.

Blue Brittleness
Brittleness exhibited by some steels after being heated to some temperature within the range of 300 (degrees) to 650 (degrees) F, and more especially if the steel is worked at the elevated temperature. Killed steels are virtually free of this kind of brittleness.

Blue Tempered Spring Steel Strips
(See Tempered Spring Steel Strip)


  • (1) Sheets - A method of coating sheets with a thin, even film of bluish-black oxide, obtained by exposure to an atmosphere of dry steam or air, at a temperature of about 1000 0øF., generally this is done during box-annealing.
  • (2) Bluing of tempered spring steel strip; an oxide film blue in color produced by low temperature heating.

(Concerning space lattices.) Having the equivalent lattice points at the corners of the unit cell, and at its center; sometimes called centered or space-centered.

The boiler consists of a steel shell, which includes the boiler barrel, the outer firebox wrapper plate, the inner firebox, boiler back plate, smokebox tubeplate and throat plate


The coating of steel with a film composed largely of zinc phosphate in order to develop a better bonding surface for paint or lacquer.

Boron (B)
(Chemical Symbol B)- Element No. 5 of the periodic system. Atomic weight 10.82. It is gray in color, ignites at about 1112°F. and burns with a brilliant green flame, but its melting point in a non-oxidizing atmosphere is about 4000°F. Boron is used in steel in minute quantities for one purpose only - to increase the hardenability as in case hardening and to increase strength and hardness penetration.

Bottle Top Mold
Ingot mold, with the top constricted; used in the manufacture of capped steel, the metal in the constriction being covered with a cap fitting into the bottle-neck, which stops rimming action by trapping escaping gases.

(See Camber)

Box Annealing
A process of annealing a ferrous alloy in a suitable closed metal container, with or without packing materials, in order to minimize oxidation. The charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly. This process is also called “close annealing” or “pot annealing.” (See Black Annealing)

A piece of equipment used for bending sheet: also called a “bar folder.” If operated manually, it is called a “hand brake”; if power driven, it is called a “press brake.”

A diamond penetrator, conical in shape, used with a Rockwell hardness tester for hard metals.

Brass (Cartridge)
Strip. 70% copper 30% zinc. This is one of the most widely used of the copper-zinc alloys; it is malleable and ductile; has excellent cold-working; poor hot working and poor machining properties; develops high tensile strength with cold-working. Temper is impaired by cold rolling and classified in hardness by the number of B & S Gages of rolling (reduction in thickness) from the previous annealing gage. Rated excellent for soft-soldering; good for silver alloy brazing or oxyacetylene welding and fair for resistance of carbon arc welding. Used for drawn cartridges, tubes, eyelet machine items, snap fasteners, etc.

Brass Shim
(See Shim)

Brass (Yellow)
Strip. 65% copper and 35% zinc. Known as “High Brass” or “Two to One Brass.” A copper-zinc alloy yellow in color. Formerly widely used but now largely supplanted by Cartridge Brass. 

Copper base alloys in which zinc is the principal added element. Brass is harder and stronger than either of its alloying elements copper or zinc; it is malleable and ductile; develops high tensile with cold-working and not heat treatable for purposes of hardness development.

Braze Welding
A family of welding procedures where metals are joined by filler metal that has a melting temperature below the solidus of the parent metal, but above 840 (450 C).

Joining metals by fusion of nonferrous alloys that have melting points above 800°F. but lower than those of the metals being joined. This may be accomplished by means of a torch (torch brazing), in a furnace (furnace brazing) or by dipping in a molten flux bath (dip or flux brazing). The filler metal is ordinarily in rod form in torch brazing; whereas in furnace and dip brazing the work material is first assembled and the filler metal may then be applied as wire, washers, clips, bands, or may be integrally bonded, as in brazing sheet.

Break Test (for tempered steel)
A method of testing hardened and tempered high carbon spring steel strip wherein the specimen is held and bent across the grain in a vice-like calibrated testing machine. Pressure is applied until the metal fractures at which point a reading is taken and compared with a standard chart of brake limitations for various thickness ranges.

An accident caused by the failure of the walls of the hearth of the blast furnace, resulting in liquid iron or slag (or both) flowing uncontrolled out of the blast furnace.

The cold working of dead soft annealed strip metal immediately prior to a forming, bending, or drawing operation. A process designed to prevent the formulation of Luder’s lines. Caution: Bridled metal should be used promptly and not permitted to (of itself) return to its pre-bridled condition.

Bright Annealed Wire
Steel wire bright drawn and annealed in controlled non-oxidizing atmosphere so that surface oxidation is reduced to a minimum and the surface remains relatively bright.

Bright Annealing
A process of annealing usually carried out in a controlled furnace atmosphere so that surface oxidation is reduced to a minimum and the surface remains relatively bright.

Bright Basic Wire
Bright steel wire, slightly softer than Bright Bessemer Wire. Used for round head wood screws, bolts and rivets, electric welded chain, etc.

Bright Bessemer Wire
Stiff bright steel wire of hard drawn temper. Normally drawn to size without annealing. Used for nails, flat head wood screws, cheap springs, etc.

Bright Commercial Finish
(See Finish)

Bright Dip
An acid solution into which articles are dipped to obtain a clean, bright surface.

Brinell Hardness (Test)
A common standard method of measuring the hardness of certain metals. The smooth surface of the metal is subjected to indentation by a hardened steel ball under pressure or load. The diameter of the resultant indentation, in the metal surface, is measured by a special microscope and the Brinell hardness value read from a chart or calculated formula.

Brinell Hardness Number (HB)
A measure of hardness determined by the Brinell Hardness test, in which a hard steel ball under a specific load is forced into the surface of the test material. The number is derived by dividing the applied load by the surface area of the resulting impression.

A tendency to fracture without appreciable deformation.

Multiple shaving, accomplished by pushing a tool with stepped cutting edges along the work, particularly through holes.

Primarily an alloy of copper and tin but the name is now applied to other alloys not containing tin; e.g., aluminum, bronze, manganese bronze, and beryllium bronze. For varieties and uses of tin bronze see (Alpha Bronze and Phosphor Bronze).

Brown & Sharpe Gages (B & S)
A standard series of sizes arbitrarily indicated, as by numbers, to which the diameter of wire or thickness of sheet metal is usually made and which is used in the manufacture of brass, bronze, copper, copper-base alloys and aluminum. These gage numbers have a definite relationship to each other. By this system the decimal thickness is reduced by 50% every six gage numbers -while temper is expressed by the number of B S gage numbers as cold reduced in thickness from previous annealing. For each B & S gage number in thickness reduction, there is assigned a hardness value of ¼ hard. To illustrate: One number hard = ¼ hard, two numbers hard = ½ hard, etc.

A raised area in the steel caused by an object going between the work rolls and bruising them.

Alternate bulges or hollows recurring along the length of the product with the edges remaining relatively flat.

Burn back
Fusing of the electrode wire to the current contact tube by sudden lengthening of the arc in any form of automatic or semi-automatic metal-arc welding using a bare electrode.

Heating a metal beyond the temperature limits allowable for the desired heat treatment, or beyond the point where serious oxidation or other detrimental action begins.

Burn off rate
The linear rate of consumption of a consumable electrode.

Smoothing surfaces through friction between the material and material such as hardened metal media.

A term applied to a metal permanently damaged by overheating.

The very subtle ridge on the edge of strip steel left by cutting operations such as slitting, trimming, shearing, or blanking. For example, as a steel processor trims the sides of the sheet steel parallel or cuts a sheet of steel into strips, its edges will bend with the direction of the cut (see Edge Rolling).

Burn through
 A localized collapse of the molten pool due to (Melt through)

Steel scrap consisting of sheet clips and stampings from metal production. This term arose from the practice of collecting the material in bushel baskets through World War II.

Butcher Saw Steel
A hardened, tempered, and bright polished high carbon spring steel strip (carbon content a bit higher than in wood band saw quality) with a Rockwell value of approximately C47/49.

Butt Welding
Joining two edges or ends by placing one against the other and welding them.

Butt-Weld Pipe
The standard pipe used in plumbing. Heated skelp is passed continuously through welding rolls, which form the tube and squeeze the hot edges together to make a solid weld.