Study on Reheat Cracking of Ni-base Superally, Waspaloy

概要

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This paper is concerned with reheat cracking of wrought Ni-base superalloy, Waspaloy during post-weld heat treatment (PWHT). Reheat cracking susceptibility (RC susceptibility) was ascertained by local deformability of synthetic heat affected zone (HAZ). Various factors which influence RC susceptibility were discussed in detail. Calculation of hardness of solution-treated material during heating to the temperature of PWHT was also carried out. Main conclusions in this paper are as follows : (1) Possible methods of alleviating RC susceptibility are- (a) rapid cooling during welding and rapid heating during subsequent PWHT through precipitation temperature range of γ' phase ; (b) shielding the weld zone, especially fusion boundary with inert gas to avoid oxygen contamination ; and (c) adding proper content of Ca which is effective to fix free S atoms and prevent grain boundary embrittlement caused by S segregation. (2) Hardness of solution-treated Waspaloy during heating to the temperature of PWHT can be calculated based on the linear relationship between the increment of hardness and (aging time)^<1/6>.
社団法人溶接学会の論文
1988-04-01