Improvement of the contact fatigue strength by rolling of sintered ferrous alloy rolle -2nd Report

Due to the continual improvements of powder metallurgy techniques, it is possible for sintered materials to compete the wrought materials even in some of the most demanding applications. However, strength of sintered materials was normally inadequacy, because they have a lot of pores. This paper describes a study on the effects of the amount of rolling and effective hardened depth by case hardening on the contact fatigue strength of sintered ferrous alloy compacts and the contact fatigue damage mechanisms. Porosity at the vicinity of the surfaces of rolled compacts was decreased with increasing the amount of radial feed, from which the contact fatigue strength of rolled compacts was improved. Furthermore rolling contact fatigue strength of rolled and case hardened compacts was more improved.