50キロ高張力鋼溶接継手の脆性破壊発生挙動におよぼす溶接熱・歪履歴の影響

概要

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In the welded joint having the pre-existing defect, the crack tip is subjected to thermal-strain cycle by post-welding. This strain cycle has effect upon the mechanical properties, especially upon fracture toughness. Consequently brittle fracture behaviors of the welded joint are influenced considerably by this strain cycle: Wells-Kihara Test is carried but comparing so-called "Before Weld Notch" with "After Weld Notch". Brittle fracture initiation temperature of BWN specimens is much higher than that of AWN ones. It is clarified by FEM analysis that the concentration of plastic strain during welding at the crack tip is occurred in BWN specimen. This hot-straining causes considerable deterioration of fracture toughness. BWN specimen shows a considerable susceptibility to effects of hot-straining embrittlement. The influence of this hot-straining on fracture toughness can be estimated quantitatively by COD Bending Test.
社団法人日本船舶海洋工学会の論文