Surface modification of PM gearlever

Paper in proceeding, 2010

A novel manufacturing concept for a gearlever has been evaluated by manufacturing of test components of two materials. Iron-based powders were used, and pressing and sintering was followed by a few different variants of hardening and surface densification. The components have been evaluated by means of component function testing, component fatigue testing, microstructure characterization, hardness measurements and residual stress determination. The gearlever is found to perform well in the function testing and shows also good fatigue properties that well match the demands for the intended application. The porosity in the sintered material is inhomogeneous, and some compaction-induced defects were observed in the material, which thus seems not to give any significant negative impact on the sintered product performance. The results show a doubling in hardness after hardening. If the materials were shot-peened (or shot-blasted) after hardening the surface hardness increased down to a depth of approximately 0.2 mm compared to the hardened material. The case-hardening should be applied after shot-peening to obtain significant effect on surface hardness within the outermost 0.1 mm. In principle no surface densification was created if shoot-peening was performed after hardening.