Effects of shot peening and artificial surface defects on fatigue properties of 50CrV4 steel

Abstract Shot peening processes are commonly used for improving the fatigue properties of steels. introduces a compressive residual stress field in near surface steel, which can reduce or stop growth cracks and improve properties. This study experimentally investigated effect shot on 50CrV4 steel alloys with different artificial defects. Drilling tools were to introduce defects root radii 0.585 mm 0.895 unpeened samples. The was applied drilled undrilled Scanning electron microscopy (SEM) observations, micro-hardness X-ray diffraction measurements conducted analyse characteristics shot-peened results show that leads transformation retained austenite martensite near-surface microstructure. hardness rates both increase by 8% after peening. peened samples exhibit stresses high degree isotropy surface. evaluated conducting 3-point bending tests. indicate improves life For radius mm, 500% improvement compared regardless defect depth. is 40% depth 0.2 increases 60% 200% increasing depths 0.4 0.6 mm. linked changes features mainly caused deformation hardening