小型 3 点曲げ試験片による原子炉圧力容器鋼材の J_<IC> 破壊靱性の評価(<特集>鉄鋼材料の破壊靱性)

概要

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Four methods for determining J_<IC> value using small specimens are compared on A533B Cl. 1 steel (HSST 03 Plate). Three-point bend tests are carried out at temperatures between -65 and 70℃. The crack initiation point on a load-deflection curve is determined by an electrical potential method. Besides this, precracked Charpy type specimens of A533B Cl. 1 and A542 steels are tested using the R-curve method to clarify the relation between the J integral value and COD value. The test results obtained are as follows : (1) The method proposed by RICE et al. is the most useful with respect to its simplicity, accuracy, and requirement of only one specimen. (2) The specimen size requirement for a valid J_<IC> value can be described by the following equation ; B≧25(J/σ_Y) where B is the specimen thickness and σ_Y is the yield strength. (3) The empirical results obtained with small specimens are in good agreement with those obtained with large ones. (4) The blunting line used in the R-curve method can be described by the following equation ; J=3.7σ_Y⊿a where σ_Y is the yield strength and ⊿a is the crack extension. (5) J value, COD, and lateral contraction, LC are related with each other as follows ; J/σ_Y=2.6(COD) J/σ_Y=2.0(LC) COD=0.77(LC)
社団法人日本鉄鋼協会の論文
1978-06-01