鋼のオーステナイト相の変態によって生成する各種組織の研削特性 恒温変態によって生ずるベーナイト組織の被研削性 Ｉ

Abstract

In the present study, isothermal transformation temperature, θISO of the carbon steel was changed and grinding force, grinding temperature, grinding ratio, surface roughness, and thickness of ground surface layer of the upper and lower bainite steel were investigated. The results are as follows: (1) Grinding force, grinding temperature and thickness of ground surface layer reduce to the minimum around the boundary temperature θISO of upper and lower bainite structure, whereas grinding ratio increases around this temperature. (2) Both scratching force, P of the material to be cut and energyfor plastic deformation, W, reduce at the boundary temperature of upper and lower bainite structure. This temperature correspond to that stated in (1), at which grindability is most improved. (3) The thickness of plastic deformation of the ground surface layer is most reduced around the boundary temperature of upper and lower bainite structure. Similarly, plastic flow in the direction of grinding is minor around this temperature. The changes are observed corresponding to the temperature at which concavo-convex of tensile fracture faces and sizes of dimple patterns abruptly reduce. (4) Grinding damages such as grinding burns, swell out residual of the grinding surface, etc., are most alleviated at the boundary temperature of upper and lower bainite structure.