The process of blacksmithing -
Blacksmiths work with "black" metals, especially iron. The black color comes from a layer of oxides that form on the surface of the metal during heating (called fire scale).
The term "smith" originates from the word "smite", which means to hit. Thus, a blacksmith is a person who smites the black metals.
Blacksmiths work by heating pieces of wrought iron or steel in a forge until the metal becomes soft enough to be shaped with tools such as a hammer. Heating is accomplished by the use of a forge fueled by propane, natural gas, coal, charcoal, or coke.
Blacksmiths may also employ an oxyacetylene or similar blowtorch for more localized heating. Color is important for indicating the temperature and workability of the metal: As iron is heated to increasing temperatures, it first glows red, then orange, yellow and finally white. The ideal heat for most forging is the yellow-orange color appropriately known as a "forging heat." Because they must be able to see the glowing color of the metal, many blacksmiths work in dim, low-light conditions.
The techniques of blacksmithing may be roughly divided into forging (sometimes called "sculpting"), welding, heat treating and finishing.