Effect of mechanical rolling on fatigue properties of A473M steel

The surface treatment was carried out on the surface of materials of A473M martensitic stainless steel axle sleeve by rolling technology, aiming to investigate the effect on its mechanical properties. The surface morphology and roughness, residual stress, microhardness, tensile and fatigue property were systematically studied using the SEM, white light interferometer, X-ray diffractometer, microhardness tester, EBSD, tensile tester and fatigue tester. The results show that the surface roughness of rolling specimen reduces significantly, which is about 1/5 of that of turning surface. The residual compression stress is induced near surface by rolling processing, the maximum value can reach up to 946 MPa and the residual compression stress decreases along with the depth. The thickness of the residual compression stress layer is about 200 μm. In addition, the rolling surface microhardness can be improved by 30% compared with that of turning surface and the hardened layer can be about 200 μm. As for mechanical properties, the tensile strength, yield strength and elongation of rolling specimens increase about 40%, 22% and 8% respectively compared with that of turning specimens. The fatigue life increases from 5.4×104 cycles to 1×107 cycles after rolling processing. The mechanical properties of the rolled material significantly improve, and the fatigue life significantly increases.