Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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A Study on New Technique Development for Creep Evaluation of Heat Resistant Steel Weldment (I)

내열강 용접부의 크리프 평가 신기술 개발에 관한 연구(I)

  • 유효선 (전북대학교 기계항공시스템공학부, 자동차신기술연구센터) ;
  • 백승세 (전북대학교 대학원 정밀기계공학과) ;
  • 권일현 (전북대학교 대학원 정밀기계공학과) ;
  • 이송인 (전북대학교 기계항공시스템공학부, 자동차신기술연구센터)
  • Published : 2002.12.01
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Abstract

It has been reported that the creep characteristics on weldment which is composed of weld metal(W.M), fusion line(F.L), heat-affected zone(HAZ), and base meta(B.M) could be unpredictably changed in severe service conditions such as high temperature and high pressure. However, the studies done on creep damage in power plant components have been mostly conducted on B.M and not the creep properties of the localized microstructures in weldment have been thoroughly investigated yet. In this paper, it is investigated the creep characteristics for three microstructures like coarse-grain HAZ(CGHAZ), W.M, and B.M in X20CrMoV121 steel weldment by the small punch-creep-(SP-Creep) test using miniaturized specimen($10{\times}10{\times}0.5mm$). The W.M microstructure possesses the higher creep resistance and shows lower creep strain rate than the B.M and CGHAZ. In the lower creep load the highest creep strain rate is exhibited in CGHAZ, whereas in the higher creep load the B.M represents the high creep strain rate. The power law correlation for all microstructures exists between creep rate and creep load at $600^{\circ}C$. The values of creep load index (n) based on creep strain rate for B.M, CGHAZ, and W.M are 7.54, 4.23, and 5.06, respectively and CGHAZ which shows coarse grains owing to high welding heat has the lowest creep loade index. In all creep loads, the creep life for W.M shows the highest value.

Keywords

References

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