溶接ボンド部の靱性評価に関するフラクトグラフィ的研究

概要

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Fracture toughness tests of cross-bond notch type specimens with controlled fractions of weld metal in crack front have been carried out. The processes of fracture are observed in detail by using fractographic technique. The processes of fracture of cross-bond type specimens are as follows. Cleavage fracture firstly initiates in the weld metal region, even though its region is small and away from the center of thickness. Then it propagates in the heat affected zone and the base metal region. It seems that, in the case of cross-bond type specimens, stretched zone width can be a proper parameter of fracture toughness, which depends not on stress-strain conditions but on materials. It is necessary to take note of stretched zone width in the lower toughness region, in estimating the macroscopic and average value of fracture toughness of a cross-bond type specimen. It is satisfactory to consider that the critical COD values of cross-bond type specimens used here, even though the weld metal region is away from the center of thickness, are roughly equal to those of specimens of which crack front are completely in weld metal.
社団法人溶接学会の論文
1980-11-05