Beryllium Copper C172 Sheets are an alloy of copper and 2-3 percent beryllium. Alloys of this series show remarkable age-hardening properties and an ultimate hardness of about 400 Brinell (Rockwell C43). Because of such hardness and good electrical conductivity, beryllium-copper is used in electrical switches, springs, etc. With greater tensile strength and hardness than other copper alloys, half hard temper Beryllium Copper C172 has good electrical and thermal conductivity is quite ductile, and resists both fatigue and relaxation under stress. Atmospheric performance is good, and it resists corrosion even in contact with seawater or under other high-salt conditions. With a melting point of 1800F (980C), it endures elevated temperatures well. Extended exposure to high temperatures should be limited to a maximum of 400F (240C). Caution: Avoid the inhalation of Beryllium Copper dust when processing.