Effect of Mechanical Heterogeneity on Fracture Toughness Evaluation of Steel Welds

概要

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Charpy impact test and bending COD test of specimens with mechanical and/or metallurgical heterogeneity extracted from stainless clad steels, electron beam welded joint and other welds have been conducted to clarify the effect of mechanical heterogeneity on fracture toughness evaluation of welds. Based on these experimental results and FEAI analyses of deformation behaviors of notched welded joint with heterogeneity, considerations have been carried out paying attention to the following three important problems: (i) Significance of Charpy impact test of welds. (ii) Effect of heterogeneity in strength on evaluation of fracture initiation parameter and how to evaluate the parameter controlling the local deformation behavior. (iii) Problems owing to heterogeneity in fracture toughness in evaluation fracture initiation parameter of welds. Consequently, it was pointed out that fracture initiation is mainly controlled by toughness of local embrittlement region in the vicinity of crack tip, and so, energy parameter does not necessarily become an appropriate fracture parameter of welde with mechanical/metallurgical heterogeneity. Nevertheless, local critical COD or SZW is an appropriate measure as to fracture initiation parameter. Critical COD often has a wide scatter due to quasi-pop-in behavior and detectability of crack initiation.
社団法人溶接学会の論文
1985-10-01