Copper strip and wire may be produced with a combination of high elastic limit and good corrosion resistance, making them an ideal choice for springs. The main groups of alloys are:
- Phosphor bronze, typically CW451K (PB102) with a yield strength of about 500 N/mm2.
- Nickel silver, typically CW409J (NS106).This is silver coloured and has excellent tarnish resistance.
- Copper-beryllium CW100C (CB101). This alloy is used where very high yield strength is required (greater than 1000 N/mm2). These alloys are expensive and phosphor bronze will be adequate for most engineering applications.
A useful Specification is BS EN 1654:1998 (Copper and copper alloys. Strip for springs and connectors).