Cause of Scarring on Surface of 55SiCr Spring Steel Wire

During production of 55SiCr spring steel wire, the surface of the steel wire was scarred after shot peening and drawing. The reasons for scarring were analyzed by morphology observation, chemical composition analysis, microstructure observation and microhardness test. The results show that the surface scabs were formed during shot peening. During the long-term service, cast steel shots appeared angular and work hardening resulting in the reduction of toughness and increase of brittleness; cast steel shots were easy to crack, and then residual particles formed. During shot peening, residual particles of cast steel shot tended to be embed in the matrix of steel wire, leading to the surface scratches and deformation to form massive scarring on surface of steel wire during following drawing process.