高張力鋼溶接部の破壊発生・伝ぱに及ぼす島状マルテンサイトの影響

概要

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Fracture behavior of the weld zone of 80 kg/mm^2 class HSLA steels has been investigated by means of tensile test, Charpy impact test and three point bending test. The results obtained gave convincible evidences that showed the following important role played by the martensite-austensite (M-A) constituent on the initiation and propagation processes of cracks. For ductile fracture, crack were initiated by cracking flaky M-A constituent or debonding blocky M-A constituent from ferrite matrix. Then cracks expanded to voids and developed to deep holes. The main crack was formed by coalescence of deep holes by internal necking and led to fracture of specimen with a ductile deep dimple fracture surface. On the other hand, for brittle fracture, cracks nucleated at the interface of blocky M-A constituent and ferrite matrix. Then the crack propagated into the specimen, resulting in catastrophic fracture with a brittle river pattern surface.
社団法人日本材料学会の論文
1985-06-15