Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Microstructure and Strength Characteristic of 9Cr Ferritic Heat-resistant Steel Applied to the Power Plants

발전플렌트용 9Cr 페라이트 내열강의 미세조직과 강도특성

  • Kang, C.Y. (Dept. of Metallurgical Engineering, Pukyong National University) ;
  • Lee, J.M. (Dept. of Metallurgical Engineering, Pukyong National University) ;
  • Lee, G.H. (Technical Institute, Sungwoo Metal Co., Ltd.) ;
  • Lee, M.Y. (Technical Institute, Sungwoo Metal Co., Ltd.) ;
  • Sung, J.H. (Dept. of Metallurgical Engineering, Dong-A University)
  • 강창룡 (부경대학교 공과대학 금속공학과) ;
  • 이종문 (부경대학교 공과대학 금속공학과) ;
  • 이규현 (성우금속(주) 기술연구소) ;
  • 이문용 (성우금속(주) 기술연구소) ;
  • 성장현 (동아대학교 공과대학 금속공학과)
  • Received : 1999.11.15
  • Published : 2000.01.30
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Abstract

This present study were investigated effect of Ni contents on the microstructure and strength characteristic in 9Cr ferritic heat-resistant steel added 1.7%W in place of Mo in order to restrain laves phase formation. The result obtained from this study are as follow. Volume fraction, number of particles per unite area and particle size of carbide decreased with increase of Ni contents. Other side, carbides of $M_{23}C_6$ type was mainly precipitated in this steel, but laves phases could not precipitated in spite of increasing of aging time. With increase of tempering temperature, hardness was increased, and maximum value was showed around 873k by secondary hardening due to precipitation of $W_2C$ type carbide and then, was decreased. Tensile and yield strength due to decrease precipitation amount of carbide and number of particles per unite area was decreased, but elongation and impact value was increased. In case of aged specimen after tempering than tempered specimen, strength was higher and elongation was lower due to increasing of precipitated amount of carbide and number of particles per unite area.

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Acknowledgement

Supported by : 부경대학교