| Boron (chemical symbol B) | (english) 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. |
| Boron Steels | (english) The addition of boron in the range 0.0005-0.005% to certain steels increases the hardenability. A range of boron steels is now listed in the current BS 970 and are widely used for the production of cold headed fastenings. |
| Brale | (english) A diamond penetrator, conical in shape, used with a Rockwell hardness tester for hard metals. |
| Brasses | (english) 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. |
| Break Test (for tempered steel) | (english) 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. |
| Bright Bessemer Wire | (english) Stiff bright wire of hard temper. Normally wire is drawn down to size without annealing. |
| Brinell Hardness | (english) The hardness of a metal or part, as represented by the number obtained from the ratio between the load applied on the spherical area of the impression made by a steel ball forced into the surface of the material tested. |
| Brinell Hardness Number | (english) The value of hardness of a metal on an arbitrary scale representing kg/mm2, determined by measuring the diameter of the impression made by a ball of given diameter applied under a known load. Values are expressed in Brinell Hardness Numbers, BHN |
| Brinell Hardness Test | (english) 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. |
| Brinell Hardness Testing | (english) Method of determining the hardness of materials; involves impressing a hardened ball of specified diameter into the material surface at a known pressure (10-mm ball, 500-kg load for aluminum alloys). The Brinell hardness number results from calculations involving the load and the spherical area of the ball impression. Direct-reading testing are generally used for routine inspection of forgings, and as a heat treat control function. |