EFFECT OF IN-PLANE CONSTRAINT AND TYPE OF LOADING ON FRACTURE TOUGHNESS OF TWO RPV STEELS OF PWRS

摘要

In the paper, results obtained from testing of small specimens performed within VOCALIST project at NRI Rez are presented. The VOCALIST project covered examination of constraint effect on fracture toughness for two steels representing materials of reactor pressure vessel: material A, i.e. steel of 22NiMoCr 3 7 type (similar to ASTM A 508 Grade 3 Class I), and material D, i.e. ferritic steel A533B in aged condition. At NRI Rez, a total of 79 small fracture specimens were tested, the specimens contained either shallow or deep cracks, and both tension and bending types of loading were examined. For the individual groups of specimens (bending/tension specimens with deep/shallow cracks from material A/D) Master Curve reference temperatures T_0 were determined. For material D, smaller values of T_0 for tension than for bending were found, both for deep and shallow cracks. J-Q loci for material A and D for selected temperatures were constructed and are presented in the paper. Also, in connection with construction of J-Q loci, the problems with determination of Q-stress parameter with respect to value of standardized distance rσ_0/J are addressed.