抄録
Using Mn steel, Mn-Cr steel, Mn-Cr-Ni steel and bearing steel of 5.0 mmφ cylinder, the effects of residual stresses on their oil quenching, water quenching and subzero quenching were investigated by Heyn’s method. Changes in stress due to tempering of these specimens were also measured. Changes in hardness or amount of retained austenite by these heat treatments were also studied. The results obtained are as follows; (1) The distribution of stress in all the specimens showed a stress-transformation type as it change into tension near the surface and compression at the center of the section, and the stress resulting from oil quenching was smaller than that resulting from water quenching.
(2) According to the subzero treatments after oil or water quenched, the hardness was remarkably increased and the amount of retained austenite were clearly decreased, while the distribution of stresses due to subzero treatments changes little.
(3) The residual stress began to decrease by tempering at about 200°C, decreased considerably at about 400°C and disappeared completely at 600°C.
