| Blow | (english) The impact or force delivered by one workstroke of the forging equipment. |
| Blue Annealing | (english) 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 | (english) 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 Brittleness 2 | (english) 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 Print | (english) A pen or ink line drawing reproduced (printed) on sensitized paper by direct exposure. |
| Body-Centered | (english) Having the equivalent lattice points at the corners of the unit cell, and at its center; sometimes called centered, or space-centered. |
| Boil | (english) Agitation of a bath of metal caused by the liberation of a gas beneath its surface. May be deliberately induced by the addition of oxidizing material to a bath containing excess carbon. In the later case it is called a carbon boil and CO or CO2 are liberated. |
| BOLT KIT | (english) A set of bolts or screws that ore selected to suit a particular application, i.e. pre-selected length, threads and strength to match the mounted component. |
| 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. |
| Boss | (english) A projection or an enlarged section of a casting through which a hole may be machine. |