Relationship between Rolling Contact Fatigue and Residual Stress on Contact Surface

Abstract

A rolling sliding contact fatigue test was conducted with the use of Ni-Cr-Mo-V steel discs (H=340H_B, S=250H_B) for marine main turbine's reduction gears and lubricating oil (No.200 turbine oil) at the soft-specimens slide-sweep ratio of -24% and 2100 rpm: and in the test, the X-ray diffraction techniques were used in obtaining the value of the residual stress on the contact surface where rolling fatigue pits were produced. The residual stresses closely related with; (a) the Herzian maximum pressure and the D-value (total surface roughness of the two discs/EHL minimum oil film thickness) under poorly lubricated conditions such as in D>1; (b) the repetition of contact at early stage of test. A change in the production of residual stress takes place with D=2 as boundary. In addition, the relation between pitting failure and the half breadth of distribution curve of diffraction strength is described.