鋼の燒入殘留應力に及ぼず變態及び熱收縮の影響

Abstract

Using cylindrical Ni-Fe älloy, specimens, we measured the residual stress of quenching by G. Sachs' method, and studied the mechanism of the growth-of quenching stress by changing the method of the heat treatment and the alloy elements.By this study, we found the fact that, in comparatively low nickel alloy (16% Ni), when quenching tempsrature rises higher than thansformation point, it takes the thermal stress type (Outsidecompression, inside-tension), and when quenching temperature approaches immediately above the transformation point, it takes the transformation stress type (outside-tension, inside-compression). In high Ni alloy (26% Ni), however, no matter how the quenching temperature may be, the stress distribution takes the type of transformation stress, and its value is little, too. As we (authors) thought the cause of the latter depends on "the transformation plasticity" as reported by G. Wasserman and E. Scheil, we made a simple experiment and could assure it to be true. In other words, in the case of low Ni alloy (16% Ni), transformation takes place it the viscous state of high temperature and the stress changes into non-elastic strain when it passes the range of transformation, so it is not affected by "the transformation plasticity". On the contrary, we may conclude that in the case of high Ni alloy, the transformation takes place in the elastic state in low temperature, so it reduces the stress by "the transformation plasticity".