Copper and its alloys have excellent corrosion resistance and are nonmagnetic. All copper alloys can be cast, hot or cold formed, and machined, but pure copper is difficult to machine. Some alloys are heat treatable and all will work harden.
- Beryllium Copper Alloy #25
Beryllium copper is the strongest of the non-ferrous alloys, with strengths approaching those of alloy steels (200 kpsi). It is often used in springs that must be nonmagnetic, carry electricity, or exist in corrosive environments. This alloy produces excellent spring properties due to a combination of low modulus of elasticity and high ultimate tensile strength. The alloy gains its physical properties by precipitation hardening. Beryllium copper is non-magnetic. Its electrical conductivity is about 2-4 times as great as phosphor bronze.
These alloys were originally defined as alloys of copper and tin, but now also include alloys containing no tin, such as silicon bronze and aluminum bronze, so the terminology is somewhat confusing.
- Phosphor Bronze, Grade A
Phosphor bronze offers electrical conductivity and fair spring properties. It is purchased in spring temper condition to maximize spring characteristics. Phosphor bronze is hardenable only by cold working. This material is non-magnetic. Phosphor bronze is also used for springs but unlike beryllium copper, it cannot be bent along the grain or heat treated.