Citation:
M.T. Rush, P.A. Colegrove, Z. Zhang and B. Courtot, An investigation into cracking in nickel-base superalloy repair welds. Advanced Materials Research, 2010, Volumes 89-91, pp467-472.
Abstract:
The nickel-base superalloy Rene 80 is considered very susceptible to liquation
and strain-age cracking. Material in the solutionised condition is welded using
the Cold Metal Transfer, or CMT process (with ductile filler alloy) and
autogenously using a laser. Grain size is shown to have a significant effect on
cracking. Using the CMT, welding power is shown to have high significance on the
level of cracking, whereas welding speed has little effect. When welding using
the laser, it is shown that the power and spot size are more crucial to the
material cracking than the travel speed. It is indicated that the weld bead
geometry has high significance over the occurrence of cracking, with a
relationship between welding power, weld bead geometry, and stresses controlling
the occurrence and magnitude of cracking. Further, some laser welds are analysed
after post-weld heat treatment, and there is a significant increase in cracking
after this. However, 34% of samples contained no cracking in both the as-welded
and post-weld heat treated state.
