Fundamental studies on electron beam welding of heat-resistant superalloys for nuclear plants, (1)

In this paper, the effect of the welding conditions on the characteristics of the weld geometry and the weld defects was made clear, concerning the heat-resistant superalloys for the nuclear plants. Obtained conclusion may be summarized as follows, using technical symbols which are given meaning in this report. 1) The weld defects were R-porosity and microcrack. 2) S sub(p) and Δa sub(b) are considered to be the important criteria for the evaluation of the susceptibility to the R-porosity. 3) Superalloys could be evaluated in the sensitivity to the microcrack in terms of the critical heat input to avoid microcrack q sub(cr). This q sub(cr) is considered to be one of the proper criteria for evaluating the superalloys in the susceptibility to the microcrack. 4) Most microcracks were apt to occur when h sub(c)/h sub(N) came near to 1.0. These microcracks came to occur easily with the increase of d sub(B.N)/d sub(B). (auth.)