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

• Published in: Materials and manufacturing processes Vol. 34; no. 10; pp. 1143 - 1150
• Main Authors: Wang, Long, Tang, Xiujian, Wang, Liuying, Yang, Nengjun, Chen, Xiaohu, Li, Ping, Liu, Gu, Liu, Guohao
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 27.07.2019
• Subjects: burns; Gear; metallographic structure; microhardness; residual stress
• ISSN: 1042-6914; 1532-2475
• DOI: 10.1080/10426914.2019.1605173

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 fine-grained 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.