A Dual Material Approach for P/M Automotive Camshaft Timing Sprockets

A novel approach to the manufacture of high-performance powder metallurgy (P/M) sprockets and gears has been developed. The result is advanced components with a unique combination of properties tailored to the current needs of the marketplace. This dual material or “Duplex” method allows for the selective application of dissimilar yet compatible P/M alloys in order to optimize properties and reduce costs. In the example described, expensive sinter-hardening or induction-hardening materials were used for the teeth of an automotive camshaft timing sprocket, while the core consists of a low density and low cost material. Key advantages of this approach are reduced weight and rotational inertia, increased sound dampening properties, lower cost, and a reduction in the size of the press required for compaction. The paper describes this development and contrasts the advantages to the current manufacturing methods for components of this type.