Abstract
The operating temperature has been increased to improve the efficiency of gas turbine. The most advanced Gas turbine is operated at above $1,500^{\circ}C$. Improvement in material and cooling method permit hot gas path component to run at increased temperature. But, the repair of blades which are developed with advanced manufacture technique is difficult to use normal welding. Most of gas turbine blades are made of precipitation harden nickel base superalloy, which is very hard to weld. Therefore, the employment of welding filler on blade is solid solution nickel base superalloy(Hastelloy X, Inconel 617). In this study, Tensile test in high temperature was conducted on welded GTD111DS with GTD111 to evaluate effect of variation of pre, post treatment. The result of this study showed that the specimen was treated with optimum pre and post treatment(preweld HT($1200^{\circ}C$), Post treatment($1100^{\circ}C$ HIP, $1200^{\circ}C$ + $1100^{\circ}C$ + $800^{\circ}C$ HT) is mush superior.