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A eutectoid transformation product of ferrite and a fine dispersion of carbide, generally formed at temperatures below 840 to 930 F (450 to 500 C): upper bainite is an aggregate containing parallel lath-shape units of ferrite, produces the so-called feathery appearance in optical microscopy, and is formed at temperatures above about 660 F (350 C) ; lower bainite consists of individual plate-shape units and is formed at temperatures below about 660 F (350 C). Also, 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 best developed at interrupted holding temperatures below those forming fine pearlite and above those giving Martensite.

Bamboo Grain Structure
A structure in wire or sheet in which the boundaries of the grains tend to be aligned normal to the long axis and to extend completely through the thickness.

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 showing parallel bands in the direction of rolling or working.

Inhomogeneous distribution of alloying elements or phases aligned in filaments or plates parallel to the direction of 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.

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 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.

Bath Annealing
Is immersion is 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.

Bend Radius
The inside radius of a bent section,

Bend Test
Various tests which is used to ascertain the toughness and ductility of a metal product, in which the material is bent around its axis and/ 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 employed, then you must line the jaws with some soft metal, to permit a flow of the metal in the piece 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.

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.

A solid semi-finished round or square product that has been hot worked by forging, rolling, or extrusion. An iron or steel billet has a minimum width or thickness of 1 1/2 in. and the cross-sectional area varies from 2 1/4 to 36 sq. in. For nonferrous metals, it may also be a casting suitable for finished or semi-finished rolling or for extrusion.

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.

Black Oil Tempered Spring Steel Strip (Scaleless 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
A light weight or a thin uncoated steel sheet or strip so called because of its dark oxide coloring prior to pickling. It is manufactured by two different processes.

(2) Form sheet bar on single stand sheet mills or sheet mills in tandem. This method is now almost obsolete.

(3) On modern, high speed continuous tandem cold reduction mills from coiled hot rolled pickled wide strip into ribbon wound coils to finished gage. Sizes range from 12 to 32 in width, and in thicknesses from 55 lbs. to 275 lbs. base box weight. It is used either as is for stampings, or may be enameled or painted or tin or terne coated.

Blast Furnace
A vertical shaft type smelting furnace in which an air blast is used, usually hot, for producing pih iron. The furnace is continuous in operation using iron ore, coke, and limestone as raw materials which are charged at the top while the molten iron and slag are collected at the bottom and are tapped out at intervals.

A defect in metal, on or near the surface, resulting from the expansion of gas in a subsurface zone. Very small blisters are called pinheads 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.

Ancient Definition: iron produced in a solid condition directly by the reduction of ore in a primitive furnace. The carbon content is variable but usually low. Also known as bloomery iron. The earliest iron making process, but still used in underdeveloped countries.

(2) Modern Definition: a semi-finished hot rolled steel product, rectangular in section, usually produced on a blooming mill but sometimes made by forging.

A semi-finished hot rolled product, rectangular in cross section, produced on a blooming mill. For iron and steel, the width is not more than twice the thickness, and the cross-sectional area is usually not less than 36 sq. in. Iron and steel blooms are sometimes made by forging.

A primitive furnace used for direct reduction of ore to iron.

A mill used to reduce ingots to blooms, billets slabs, sheet-bar etc.,

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

Blue Annealing
Heating hot rolled ferrous sheet in an open furnace to a temperature within the transformation range and then cooling in air, in order to soften the metal. The formation of a bluish oxide on the surface is incidental.

Blue Brittleness
Reduced ductility occurring as a result of strain aging, when certain ferrous alloys are worked between 300 and 700 (degrees) F. This phenomenon may be observed at the working temperature or subsequently at lower temperatures.

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.

Subjecting the scale-free surface of a ferrous alloy to the action of air, steam, or other agents at a suitable temperature, thus forming a thin blue film of oxide and improving the appearance and resistance to corrosion. NOTE: This term is ordinarily applied to sheet, strip, or finished parts, It is used also to denote the heating of springs after fabrication in order to improve their properties.

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

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 ( chemical symbol B)
Element N. 5 of the periodic system. Atomic weight 10.82. It is gray in color, ignites at about 1112 (degrees) F. and burns with a brilliant green flame, but its melting point in a non-oxidizing atmosphere is about 4000 (degrees) 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.

Box Annealing
Annealing a metal or alloy in a sealed container under conditions that minimize oxidation. In box annealing a ferrous alloy, 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.

Box Annealing
A process of annealing a ferrous alloy in a closed metal container, with or without packing materials, in order to minimize the effects of oxidation. The charge is normally heated slowly to a temperature below the transformation range, but occasionally above or within it, and then is slowly cooled.

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.

Copper base alloys in which zinc is the principal alloying element. Brass is harder and mechanically stronger than either of its alloying elements copper or zinc. It is formable and ductile; develops high tensile strength with cold-working and is not heat treatable.

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 (425C), but lower than those of the metals being joined. May be accomplished by a torch. 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 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.

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
The process of annealing in a protective atmosphere so as to prevent discoloration of the bright surface desired.

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 wire of hard temper. Normally wire is drawn down to size without annealing.

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

Brinell Hardness Test
A common standard method of measuring the hardness of materials. The smooth surface of the metal is subjected to indentation by a hardened steel ball under pressure. The diameter of the indentation, in the material surface, is then measured by a microscope and the hardness value is read from a chart or determined by a prescribed formula.

Brittle Fracture
Fracture preceded by little or negligible plastic deformation.

The tendency of a metal or material to fracture without undergoing appreciable plastic deformation.

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

Primarily an alloy of copper and tin, but additionally, the name is used when referring to other alloys not containing tin, for example, aluminum bronze, manganese bronze, and beryllium bronze.

Brown & Sharp Gages (B&S)
A standard series of sizes refered to by numbers, in which the diameter of wire or thickness of sheet metal is generally produced 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. In 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, where is assigned a hardness value of 1/4 hard.

Bulges and/ or hollows occurring along the length of the metal with the edges remaining otherwise flat.

A substance added to aqueous solutions to maintain a constant hydrogen-ion concentration, even in the presence of acids or alkalis.

Permanently damaging a metal or alloy by heating to cause either incipient melting or intergranular oxidation.

(2) In grinding getting the work hot enough to cause discoloration or to change the microstructure by tempering or hardening.

(3) 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.

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

A definition applying to material which has been permanently damaged by over-heating.

Roughness left by a cutting operation such as slitting, shearing, blanking , etc.

Butcher Saw Steel
A hardened, tempered, and polished high carbon spring steel strip material (carbon content is generally higher than that of a material used for wood band saw applications) with a Rockwell value of roughly C47/49.

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