Influence of Precipitates in Automobile Spring Flat Steel 50CrVA on Its Properties

The early fatigue fracture of 50CrVA leaf spring produced by converter process was analyzed by means of chemical analysis, hardness test, metallographic examination and electronic energy spectrum. The results show that there are not only serious nitride inclusion and slag entrapment defects, but also a large number of bainite structures in the fatigue fragments. It is shown that the fatigue life of spring steel can be effectively increased by improving metallurgical quality and heat treatment process.