HT80 鋼溶接部における遅れ割れとその破壊力学的評価(第 2 報) : 遅れ割れからぜい性破壊への遷移挙動と J 積分

概要

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Delayed crack behaviour from a notch of poor penetration in a weldments of HT80 steel of 31mm thickness has been investgated. Three points bend specimens of 70mm width with weld defect of poor penetration were welded. In these specimens, the tip of the notch was located on a fusion line in modified-Vee joints. J integral has been applied to evaluate the delayed fracture toughness in coarse grained HAZ. Results can be summarrized as follows : 1) Fracture mode of the pressure vessel at proof loading, that is the transition from stable delayed cracking to unstable cleavage fracture, can be easily reappeared by the laboratory test proposed in this report. 2) The susceptibility to delayed cracking in the weldments of HT80 steel can be successfully evaluated as a function of J integral. 3) A new method to evaluate delayed fracture toughness has been proposed. This method is based on three parameters method proposed by S.J. Garwood et al. 4) Delayed fracture toughness's transition curve is shifted to higher temperature side than fracture toughness's transition curve by 25℃.
社団法人溶接学会の論文
1979-02-05