Tin bronze
Tin bronze is a copper alloy with about 5 to 12 % tin — and no beryllium. It's tough, wear-resistant, and seawater-resistant. Classics are CuSn6 and CuSn8 for plain bearings, worm gears, and fittings.
What is Tin Bronze
Tin bronze is a copper alloy with tin as the main alloying element, usually 5 to 12 %. Depending on tin content and other additions (zinc, lead, phosphorus), its properties vary. Important: it contains no beryllium, so it's not a health concern when machining.
Properties
Tin bronze is tough, has good sliding properties, is wear-resistant, and resists seawater. That's why it's used in plain bearings, worm wheels, pumps, and fittings. As tin content increases, hardness rises and toughness drops.
Welding and Brazing
Tin bronze welds quite well with TIG or MIG, DC plus. Use a CuSn filler wire of matching grade (DIN EN ISO 24373). Thin sections don't need preheat, but thicker ones need 150 to 300 °C preheat because copper conducts heat away quickly.
Pitfall
Make sure surfaces are clean and free of grease: copper absorbs hydrogen in the weld pool, and pores form on solidification. Remove grease, oil, and moisture thoroughly beforehand.