What are “hard metals?
” A: Hard metals are metal alloys with properties of extreme hardness, wear-resistance, and high temperature stability. Hard metals are used for cutting and drilling tools, as well as for metalworking dies and special machine parts. Hard metal alloys are actually metal composites, made by mixing metal carbides and binder metals in powdered form, and then pressing the compound into desired shapes under high temperature and pressure. Tungsten carbide is the most commonly used hard metal in the U.S. Cobalt is the most common binder metal. The amount of cobalt in most hard metal alloys varies from as little as 2 percent up to 25-30 percent. Certain hard metals, such as “stellite,” may contain more than 50 percent cobalt, although airborne cobalt exposures with stellite grinding may be lower than with grinding other hard metals. Cadmium is common in the brazing solders used to attach hard metal pieces to other metal pieces. Q: Which operations involve exposure to hard metals that could be a
