Welding of the Ni-base wrought superalloy · GH698

摘要

The welding technology of the Ni-based wrought superalloy -GH698 alloy components was studied. The mechanical properties of joints were tested. The microstructures and the precipitation phases such as the carbides of the joints were observed and analyzed using the OM (optical microscope) and SEM (scanning electronic microscope). The results show that the GH698 alloy is weldable with the filler metal HGH533 using the TIG (tungsten-inert-gas arc welding) technology and that sound weld can be obtained. With the post-weld heat treatment at 775℃ for 16 hr., the tensile strength of the joint at ambient temperature is close to that of the base metal, and the tensile strength of the joint at the high temperature is 92% of that of the base metal. The post-weld heat treatment has no detrimental effect on the base metal. It also shows that welded under water-cooling condition, the GH698 alloy exhibits high cracking resistance. On the basis of these results, some load-bearing components of an engine have been successfully repaired.