Regularities of Softening of Thermally Hardened Steels during Welding,

During welding of thermally hardened steel a new phenomenon must be reckoned with - softening in the heat affected area. As a result of welding heating in the weld joint there is formed a soft interlayer, which disturbs the mechanical homogeneity. The provision of uniform strength and mechanical homogeneity of the weld joint is the basic specific problem of welding of the thermally hardened steels, for the solution of which it is necessary to find methods of controlling the processes of softening. In connection with this the regularities of softening are of interest, the knowledge of which permits rationally directing the development of the chemical composition of new mild steels and welding technology, and also permits considering the effect of the soft interlayer when designing structures. In certain cases, in the authors opinion, the reasons for the limitation of softening by the chemical composition of steel are erroneously explained, which can lead to the irrational consumption of scarce alloying elements. Author