Copper-Tin Wrought Alloy Formability

Copper-tin alloys, i.e. tin bronze, can be cold-formed well if the tin content is not too high. When welding, however, the material becomes hard and brittle because a different microstructure forms. If you then bend or form the part further, it will crack quickly. So you have to anneal the weld seam to make the structure formable again. If you don't do that, the component stays brittle and breaks under load.