Tooth Root Bending Stress Analysis of Pre-alloyed Sintered Steel Gears with Different Densities using FEM Model Considering Voids

Abstract

Bending durability tests were carried out using P/M spur gears made from 1.5Cr-0.2Mo pre-alloy sintered steel powder (FL520X) with a density of 7.40 Mg/m 3 (GH1) and 7.55 Mg/m 3 (GH2). The P/M gear specimens were machined from the sintered packs made by the single-press single-sinter route, and some were surface-rolled using a CNC form-rolling machine of two roller-dies type. All of the test gears were case-carburized. The bending durability was investigated by single tooth bending fatigue tests using a pulsator. A two-dimensional finite element simulation model were constructed and examined the effects of the void distributions and the surface densification depths on the bending stress distributions at the critical section on the root fillet of gear tooth flank. Both the experimental and the analytical results show that the bending durability and the stress level of surface-rolled GH1 completely matches that of GH2, whose bending fatigue strength is higher than the target level of 1 GPa.