| Bloomery | (english) A primitive furnace used for direct reduction of ore to iron. |
| Blooming-Mill | (english) A mill used to reduce ingots to blooms, billets slabs, sheet-bar etc., |
| Blow Back | (english) A coating defect consisting of a lower coating film weight on the bottom of the coated sheet caused by high velocity air in the oven. Blow back usually occurs with high solids coatings which have little solvent to evaporate and "set" the film. |
| Blow Down | (english) Process that rids boiler feed water of solids and maintains the proper chemical balance of the feed water. Blow down can also be used to rid drum(s) of excess water. |
| Blowhole | (english) A defect in a casting caused by trapped steam or gas. |
| 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. |
| 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. |
| 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. |
| Boiler | (english) A closed vessel in which water, is transformed into steam at a given pressure and temperature under controlled conditions. |