Effect of Specimen Size on the Fracture Toughness of Type 304 Stainless Steel. Interim Report

摘要

The effect of specimen size on the elastic-plastic fracture toughness behavior of Type 304 stainless steel was characterized by the multiple-specimen J-R curve technique at 427 exp 0 C. Fracture tests were performed on five compact specimen sizes: 2.5T (thickness = 63.5 mm), 2.5T (thickness = 14.7 mm), 1T (thickness = 25.4 mm), 1T (thickness = 14.7 mm), and 0.577 (thickness = 14.7 mm). In comparison with the 63.5-mm thick 2.5T specimen results, the smaller specimens exhibited higher J/sub Ic values and lower R-curve slopes (dJ/da). However, the differences in J/sub Ic/ and dJ/da were not statistically significant for the 2.5T and 1T specimens, which suggests that size effects for 1T and larger specimens are relatively small or nonexistant. On the other hand, there was a statistical difference between the 0.577T and 2.5T J/sub Ic/ values.