International round robin test results of J-evaluation on tensile test at cryogenic temperature within the frame work of VAMAS activity

A new J-evaluation method named JETT has been investigated through international round robin tests within the frame work of VAMAS activity. On the first stage, SUS316LN was tested as a common test material and it was found that JETT has potential to clarify the local fracture toughness. During last two years, 9% Ni steel was used and the effect of serrations on the toughness was investigated. As the results, the serration produces additional blunting at the notch tip resulting in delaying the crack initiation and giving higher fracture toughness. Nevertheless, it is recognized that JETT is a very conventional method to evaluate a relative toughness at the local area of the material.