Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Microstructural Evolutions and Microhardness of the Heat Treated Ni-base Superalloy Weldment

Ni기 초합금 용접부의 열처리에 따른 미세조직 변화와 미세경도

  • Kim, G.S. (Dept. of Materials Engineering, Soonchunhyang University) ;
  • Ji, J.H. (Dept. of Materials Engineering, Soonchunhyang University)
  • 김광수 (순천향대학교 공과대학 신소재공학과) ;
  • 지정훈 (순천향대학교 공과대학 신소재공학과)
  • Received : 2005.08.26
  • Accepted : 2005.09.20
  • Published : 2005.09.30
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Abstract

This study was performed to determine the repair weldability of the damaged Ni type superalloy used for gas turbine blade. The experimental works included the evaluation of the microstructures of the damaged blade, selection of the repair welding procedure, characterization of repair weldment and finding the heat treatment procedures for repaired weldment. The morphology of the microstructure for the base metal was composed of austenite matrix with cubical ${\gamma}^{\prime}$ phase, MC type coarse precipitates located within grain and fine $M_{23}C_6$ type precipitates decorated at grain boundaries. The repair welding process using 90 amp current exhibited the best weld properties showing no weld microcracks. The solution and aging heat treatments of the repaired weldment could recover the original service properties of the damaged blade.

Keywords

Acknowledgement

Supported by : 기초전력연구원

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