Forging is often categorized according to the temperature at which it is performed—cold, warm, or hot forging. A wide range of metals can be forged.Forging is now a worldwide industry with modern forging facilities producing high-quality metal parts in a vast array of sizes, shapes, materials, and finishes. Metal is heated before it is manipulated to the desired shape using a forging hammer. This used to be done by hand by blacksmiths.