Abstract
Both the effect of compressive mean stress on fatigue properties of non-rolled specimen and the effect of compressive residual stress on fatigue properties of plastic deformed specimens by roller-working were investigated. Pulsating fatigue test have been performed using the specimens with or without surface deformation. The main results obtained in this study are as follows; (1) According to increase of the compressive mean stress from 0, -61.25, -122.5 and -183.75 MPa, the fatigue limits of these specimens also increase to 255, 288, 388, and 428 MPa. (2) The fatigue limit of rolled specimen D2 is 500 MPa, which is higher than that of non-rolled specimen ND0 by 196 %. The above difference would be caused by compressive residual stress and work-hardening due to roller working. (3) The rolled specimen shows two steps of fracture mode, i.e., shear fracture mode and tensile fracture mode. (4) According to the above results, the compressive mean stress and compressive residual stress delay crack initiation and suppress remarkably the transition from crack initiation to propagation.
