The Effects of V and Mo Addition on Microstructure and Mechanical Properties of 60SI2CR Spring Steel for Grinding Balls

Effects of V and Mo micro-alloy elements on the microstructure and mechanical properties of 60Si2Cr grinding ball steel were studied by means of optical microscope, scanning electron microscope, tensile test, impact test and Rockwell hardness test. Results show that by adding 0.12wt%Mo to 60Si2Cr grinding ball steel, less cementite can be precipitated from the matrix than adding 0.08wt%V, so that the hardness of wear-resistant steel ball is higher. The addition of V can refine the needle-like martensite structure, which is conducive to the improvement of impact toughness. The best comprehensive mechanical properties can be obtained by adding 0.12wt%Mo and 0.08wt%V simultaneously, with the ultimate tensile strength (UTS) of 2 277.7 MPa, the yield strength (YS) of 1 753 MPa, the near surface hardness (SH) of 62 HRC, the core hardness (CH) of 60.7 HRC, and the impact energy of 54.3 J/cm^2. The results show that the addition of 0.08wt% V and 0.14wt%Mo to 60Si2Cr grinding ball steel can effectively improve the impact toughness and hardness.