Below is a list of Cold Forging manufacturers from Diamond Bar, California. Cold forging, also known as cold heading, is a metal forming process that involves the plastic deformation of metal by squeezing the material through an open die using an unheated billet and causing the finished part to assume the shape of the die. Unlike most forging, which is performed hot at temperatures nearing or exceeding 2300 degrees F, cold forging is performed at below the re-crystallization temperature of the metal, at anywhere from room temperature to several hundred degrees F.