THE EFFECTS OF DEAERATED WATER ON THE TOUGHNESS OF NICKEL-BASED ALLOYS

摘要

The fracture toughness of nickel based alloys can be degraded when exposed to low temperature deaerated water. This paper uses elastic-plastic fracture mechanics testing to explore some fundamental environmental and metallurgical factors that influence this form of environmentally assisted cracking. Elastic-plastic fracture toughness tests were performed on 0.6T compact tension samples of EN82H weld metal as a function of temperature, hydrogen content in the water, and hydrogen content in the weld metal. Tests were also performed on EN52 and three candidate replacement alloys for EN52 in order to compare their low temperature crack propagation resistance to EN82H. These results are used in conjunction with literature data and fundamental understanding to outline the environmental and material conditions that promote susceptibility to this form of hydrogen embrittlement.