抄録
The typical plastic flow that occurs under repeated passages of load by rolling contact, was reproduced by the use of a two-disk wear testing machine. As for the modes of cyclic loading, pure rolling contact, rolling contact driven by frictional force and rolling-sliding contact were applied.
Residual stress was measured by means of X-ray diffraction with Dölle's analyzing method (8). The changes in micro-Vickers hardness and half-value width of X-ray diffraction pattern along the depth direction were measured, and the following results were obtained: The major residual stress components σx and σy were compressive, and others were relatively small, less than ±50MPa. The value of σx decreased from the surface layer to the depth direction showing maximum in the region where plastic flow is observed, while σy showed a maximum value at the surface and decreased along the depth direction. The distributions of these residual stress components along the depth direction were consistent with the analytical calculation by the method of Merwin et al. (6). In the case of rolling-sliding contact, the additional residual shear component τzx was observed. In the plastic flow zone caused by tangential force at the surface, marked work hardening and broadening of half-value width were observed. In the region of plastic flow caused by Hertzian stress, however little work hardening effect and minor broadening effect of half-value width were found.
