Distinguishing effect of turning and grinding on the surface integrity and fatigue performance of ultra-high strength steel

The final processing techniques for ultra-high strength steel typically involve turning and grinding. The selection of processing parameters is crucial in determining the surface integrity and fatigue behavior of the resulting parts. This study investigates the surface integrity of 45CrNiMoVA steel, including surface roughness, residual stress, and microhardness, as well as its low cycle torsional fatigue behavior, such as fatigue life and fatigue fracture morphology. The effects of different turning and grinding allowance conditions on surface integrity parameters and fatigue behavior are examined. In addition, this text analyzes the differences between the surfaces produced by turning and grinding. It examines the microscopic factors that affect surface quality and fatigue life by considering crystallographic characteristic parameters. The results show that the specimens that subjected to fine turning exhibit poor surface morphology, high compressive residual stress, high microhardness, and the longest fatigue life. Among the various grinding allowance distributions, RFGF1 is considered relatively optimal. It consists of a rough grinding allowance of 0.45 mm and a fine grinding allowance of 0.15 mm, with the use of cutting fluid.