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Malleable and ductile cast irons are used extensively in automotive applications such as clutches, gears, carriers, shafts, bearings, cam, racers, hubs, etc. Recently developed P/M materials can be processed cost efficiently to replace malleable and ductile iron castings. An UTS in excess of 1240 MPa and a YS in excess of 825 MPa can be achieved with one of these new materials. These tensile properties can be coupled with elongations over 2% and impact energies over 25 Joules. This presentation will cover processing routes for these new materials and will identify parts that may benefit from this new technological advancement.

Model testing for rolling contact fatigue (RCF) strength is an important tool for pre-selecting materials and processes for highly loaded gear applications. S-N curves based upon final and catastrophic failure are used to compare material compositions and effects of process parameters in order to improve life time until fracture. The introduction of eddy current technology to detect cracks in the very early stages of nucleation is about to change failure definition in RCF and allows a completely new approach to understanding initiation and propagation of flaws and failures in RCF. This paper describes the fundamental principle of eddy current technology in RCF testing and presents first results on wrought and PM steels. It also contains first test results on crack propagation at different levels of contact pressure, even below the “endurance” limit. The practical consequences of the new approach will be discussed, as well as the impact on future model testing procedures.