MICROSTRUCTURAL CHARACTERIZATION OF SURFACE MODIFIED ALLOY 82 WELDS REGARDING SUSCEPTIBILITY TO ENVIRONMENTALLY ASSISTED CRACKING

摘要

Nickel alloys are used in the fabrication of nuclear power plants both as wrought components and as weld materials. Nickel based weld materials include Alloys 82, 182 and 52. Nickel alloys may suffer environmentally assisted cracking during service in nuclear power plants. Several factors affect the susceptibility of nickel alloys to cracking in service including internal or metallurgical factors and external or environmental factors. One of the internal detrimental factors could be the presence of cold work in the alloy. Superficial cold work may be introduced into a component during fabrication such as surface grinding. The objective of the present research was to quantify the damage introduced into an Alloy 82 weld during grinding and how this damage could be mitigated by subsequent electropolishing. The implications regarding susceptibility to stress corrosion cracking are also discussed.