Causes of surface indentaion and quality improvement of 42CrMoA steel for internal combustion engine crankshaft

Aiming at the problem that the surface indentation of 42CrMoA steel bar blank used in a batch of internal combustion engine crankshaft was obvious after sandblasting, macroscopic observation, chemical composition analysis, macroscopic examination, metallographic examination and scanning electron microscope analysis were used to study the 42CrMoA steel bars corresponding to different surface quality crankshaft blanks, and the improved verification test scheme was designed. The results show that the generation of crankshaft surface indentation was not related to the original surface roughness of the bar, but related to the original chemical composition of the bar. Appropriately increasing the content of S and Al elements and controlling the content of P, Ni and Cu elements could improve the indentation of crankshaft blank surface.