Experiment Study on Micro-Hardness and Structure of NC Grinding Surface Layer of Spiral Bevel Gears

Through the analyses of experiment,mechanism of dislocation and coupling of grinding temperature and deformation field,many conclusions are gotten.Firstly,a tempering metamorphic layer of lower hardness is formed in hardening zones of grinding layer of spiral bevel gear. Secondly,the microstructure of grinding tooth surface is acicular martensite+residual austenite+ a small amount of carbides,and it’s outside to the inside presents the variation of "fine→coarser→finer".Thirdly, the critical condition of grinding burns is obtained,that is when grinding temperature is above 600°C,metamorphic layer depth is greater than 0.2mm or more. The formation characteristics of grinding cracks is also revealed. These provide a basis for the NC grinding quality control of spiral bevel gears.