RCF-testing of Selectively Densified Rollers of P/M Materials for Gear Applications
PM²TEC 2002, in Orlando, USA. Authors: Pernilla Johansson, Sven Bengtsson, Senad Dizdar. Selective densification can be an appropriate way to fulfill high demands on rolling contact fatigue (RCF) resistance of P/M materials for gear applications. Pre–alloyed P/M materials were tested us-ing the ZF-RCF test. Reference material was low-alloyed case hardened steel DIN 16MnCr5 (AISI 5115) commonly used for gear applications. Test samples, rollers Ø 30X30 mm, were pressed from different test materials as cylinders, machined to an oversize compared to the finished roller, selectively densified on a rolling machine and finally heat treated in different ways. The tested roll-ers were characterized with respect to microstructure, mechanical properties, and surface character-istics. Damage mechanisms were examined and failure analyses were performed on the rollers in or-der to trace crack initiation and propagation.