| Boring Tool | (english) A cutting tool in which the tool bit,the boring bar and in some cases the tool holder are incorporated. |
| 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. |
| Boss | (english) A projection or an enlarged section of a casting through which a hole may be machine. |
| Bottle Top Mold | (english) 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. |
| Bottom Die | (english) The stationary half-die. |
| Bottom Roll | (english) Submerged roll in the pot used to keep the strip submerged in the pot. |
| Bottom Up | (english) Reversing the wrap of a coil putting the top surface on the bottom. |
| Bow | (english) The lateral deviation from straightness |
| Box | (english) Interanl (female) threaded end. |