Mechanism of grinding-induced burns and cracks in 20CrMnTi steel gear

摘要

To investigate the characteristics and formation mechanism of grinding-induced burns and cracks in 20CrMnTi steel gear, diverse distribution characteristics including metallographic structure, Microhardness, and residual stress of the gear surface were analyzed. Under the effect of thermal-mechanical coupling, the transformation mode of metallographic structures led to different degrees of grinding burns, showing the unique nature of each affected layer. When subjected to tempering-induced burn, martensite was transformed into troostite or sorbite to thus decrease the microhardness and initial residual compressive stress. When being subjected to quenching-induced burn, the finegrained white layer formed, and the surface microhardness was enhanced, but the residual compressive stress on the gear surface was transformed into tensile stress, resulting in the generation of grinding-induced cracks. By optimizing the grinding parameters and conducting shot peening strengthening treatment, grinding-induced burns or cracks can be prevented.