Temper carbon

Irregular, cauliflower-like carbon aggregates formed by prolonged annealing of white cast iron. They transform a brittle raw casting into a tough, machinable component.

Temper carbon forms when white cast iron is annealed. The carbon from the cementite in the structure is redistributed and forms nodular graphite precipitates. This makes the material tougher and easier to machine. When welding malleable cast iron, you have to be careful: The heat can dissolve the temper carbon again and locally alter the structure. The weld then becomes hard and brittle, and cracks can occur. If you are unsure how the casting was treated, ask or do a test weld on a scrap piece.

MetallurgieSchweißtechnik