Fracture Toughness Assessment for JN 1 Austenitic Stainless Steel Rolled Plate at Liquid Helium Temperature

Abstract

In order to evaluate the fracture toughness of CSUS-JN 1 austenitic stainless steel rolled plate for superconducting magnet structures of magnetic fusion reactors, we have performed elastic-plastic fracture toughness testing at 4.2K. 1T compact test specimens and computer controlled unloading compliance method are used for the J_IC tests. The effects of specimen thickness and side-groove on J_IC and T_mat are examined. SEM fractograph reveals the effect of specimen thickness on fracture surface. The effect of crack tunneling on determination of J-R curve and J_IC, and a difference between ASTM E 813-81 and E 813-87 are also discussed.