Abstract
In succession to the previous experiments, we have studied the influence of alloying elements (C, Ni, Cr), various heat-treatments and diameters of specimeus on residual stresses of quenched Fe-base alloys by Heyn’s method. The results with full hardening are as follows: Residual stresses of steels are closely related with their cooling dilatation curves. These are much influenced by the expansion caused by the transformation as the transformation point are depressed by the increase of alloying elements. Therefore, these are powerfully influenced by carbon contents. The residual stresses of alloying steel samples are markedly influenced by the carbon contents of austenite when these samples transform at lower temperature. For instance, the residual stress of 21% Ni-Fe alloy samples are different from that of 1.1% carbon steel samples in spite of resembling cooling dilatation curves, i.e. the effect of thermal stress is not apparently recognized in the residual stress of 21% Ni-Fe alloy samples quenched from high temperature. But both the effects of thermal stress and transformation stress are clearly recognized in 1.1% carbon steel samples quenched from the same temperature. Moreover, residual stresses of steel samples containing two or more alloying elements are similar to that of carbon steel samples of the same cooling dilatation curves if these steels contain 0.2 per cent or more carbon contents. Therefore, 0.2 per cent or more of carbon content of high alloying steel samples have a potent effect on susceptibity to cracking.
