| Blowhole | (english) A defect in a casting caused by trapped steam or gas. |
| Blowhole 2 | (english) A cavity which was produced during the solidification of metal by evolved gas, which in failing to escape is held in pockets. |
| 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. |
| Blue Vitriol Copper sulfate | (english) A layout solution which turns a copper color when applied to a clean,polished metal surface. |
| Blush | (english) A coating defect consisting of the whitening of a cured film which results in a translucent or opaque appearance with accompanying loss of gloss. Blushing usually occurs during the pasteurization or steam processing of films which are undercured or water sensitive. |
| 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. |
| Bonderized Coating | (english) A thin film of phosphate pretreatment applied to a steel surface (bare or zinc coated) to enhance paintability. |