厚板補修溶接部の脆性破壊強度評価

概要

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3-dimensional welding residual stress distribution of repair weld was measured and a wide plate test with a surface notch at repair weld was carried out. The brittle fracuture strength from the 3-dimensional crack at the repair weld was evaluated using COD criterion. The results of the present study are summarised as follows. 3-dimensional welding residual stresses in the thickness direction are measured. These values are seemed to be independent of the repair weld depth. CTOD values obtained from wide plate test are equivalent to those from COD test, provided that the microstructure of the notch tip is similar between them. The brittle fracture strength of the 3-dimensional crack at the repair weld is reasonablly estimated by using equivalent 2-dimensional crack, COD design curve and the criterion of δ_R+δ_σ=δ_c,where δ_R,δ_σ andδ_c are CTOD due to residual stress, applied stress (strain) and its critical value, respectively. The effect of welding residual stress is analysed quantitatively by means of the proposed method of the present study, but practically, WES 2805 gives the reasonable and safety-side estimation for it.
社団法人日本船舶海洋工学会の論文