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The successful integration of P/M into a large number of subassemblies can depend on the ability to join P/M components to each other and to wrought materials. Common methods of joining metal components, such as brazing and welding, can give unexpected results when applied to P/M. The purpose of this paper is to investigate the joining of P/M components of varying hardenability, density, and composition using friction welding, high speed pulse welding, gas tungsten arc welding, and brazing. The joints are evaluated using ultimate strength, microhardness, and microstructure. The results show that solid state process, such as high speed pulse welding and friction welding are applicable to all but the highest hardenability materials. Gas tungsten arc welding has less applicability due to crack formation upon cooling. Brazing is generally applicable with most P/M materials assuming a suitable filler metal is selected.

Brake drum failure due to cracking is a significant concern in the design of automotive brake systems. A dynamometer simulation of typical highway driving conditions indicated that for a gray cast iron drum to be resistant to large crack formation under typical driving conditions it should have a high graphite content. Drums with a relatively thin wall may also be more resistant to large crack formation however additional testing is required. Graphite flake length and drum hardness were not found to have an effect large crack formation. Defining the characteristics of drums resistant to large crack formation and failure can lead to safer, more efficient drum designs.