Ih. Kwon et Hs. Yu, Cryogenic fracture toughness evaluation for austenitic stainless steels bymeans of unloading compliance method, KSME INT J, 15(1), 2001, pp. 26-34
Most research to date concerning the cryogenic toughness of austenitic stai
nless steels has concentrated on the base metal and weld metal in weldments
. The most severe problem faced on the conventional austenitic stainless st
eel is the thermal aging degradation such as sensitization and carbide indu
ced embrittlement. In this paper, we investigate the cryogenic toughness de
gradation which can be occurred for austenitic stainless in welding. The te
st materials are austenitic stainless JN1, JJ1 and JK2 steels, which are ma
terials recently developed for use in nuclear fusion apparatus at cryogenic
temperature. The small punch(SP) test was conducted to detect similar isot
hermally aging condition with material degradation occurred in service weld
ing. The single-specimen unloading compliance method was used to determine
toughness degradation caused by thermal aging for austenitic stainless stee
ls. In addition, we have investigated size effect on fracture toughness by
using 20% side-grooved 0.5TCT specimens.