11.6.2003 Pressing & Sintering

Process, Quality and Properties of High Density P/M Gears

PM²TEC 2003, in Las Vegas, USA.  Authors: Senad Dizdar, Paul Skoglund, Sven Bengtsson. High-performance P/M test-gears made by a high-density manufacturing route and sinter-hardening have been experimentally investigated with respect to dimensional accuracy and mechanical properties. The properties of the gears, compacted to a density of 7.5 g/cm³, were compared to the properties of gears made of heat-treated wrought steel. Dimensional- and surface finish features of the P/M prototypes equal to that of conventionally manufactured gears made of wrought steel. The AGMA and DIN gear quality numbers for profile-, alignment- and pitch deviation of net shape sinter-hardened gears were comparable with hobbed gears. P/M gears can thus offer significant cost savings due to fewer costly machining operations such as turning and hobbing and due to better materials utilization compared to conventional gears. The endurance limit of the sinter-hardened P/M gears at a density of 7.5 g/cm³ was similar to that of a quenched and tempered (SAE4140) wrought steel material, commonly used for medium-duty gears.