This study aims at reducing costs of high load gear manufacturing, and substituting P/M gears for conventional wrought steel gears. In order to improve the fatigue strength of P/M gears, we focused on the rolling and the high performance sintered and heat treated 4600 series alloy steels with mezzo-heterogeneous microstructure which were made from the mixed elemental powders. The fatigue strength was determined by single tooth root bending fatigue test machine, and the effect of mezzo-heterogeneous microstructure and rolling on the fatigue strength was mainly investigated. The endurance limit at <I>N</I>=3.0×10<SUP>6</SUP> of the 500 <I>μ</I>m rolled 6 % Ni alloy steel gear compact showed 950 MPa which value is about 2/3 of the case hardened wrought steel (SCM415) gears. However, the endurance limit of rolled and heat treated gear compact showed lower value (630 MPa) as compared to as-rolled gear compact. This seems to be due to the decreasing the compressive residual stress by heat treatment and unfavorable mezzo-heterogeneous microstructures.
|Translated title of the contribution||Effect of Mezzo-Heterogeneous Microstructure and Rolling on the Tooth Root Bending Fatigue Properties of Sintered Ni Alloy Steel Gears|
|Number of pages||5|
|Journal||Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy|
|Publication status||Published - Jun 15 2011|