Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Tensile properties and Spot Weldability of Trip High Strength Steel Sheet

Trip형 고장력강판의 인장성질 및 점용접성

  • Kang, C.Y. (Dept. of Metall. Eng., Pukyong National University) ;
  • Kim, H.J. (Dept. of Metall. Eng., Pukyong National University) ;
  • Kim, C.G. (Dept. of Metall. Eng., Pukyong National University) ;
  • Lee, B.W. (Dept. of Metall. Eng., Pukyong National University) ;
  • Lee, M.Y. (Technical Institute, Sungwoo Metal Co., Ltd.) ;
  • Lee, G.H. (Technical Institute, Sungwoo Metal Co., Ltd.) ;
  • Kim, T.I. (Technical Institute, Sungwoo Metal Co., Ltd.)
  • 강창룡 (부경대학교 공과대학 금속공학과) ;
  • 김효정 (부경대학교 공과대학 금속공학과) ;
  • 김창규 (부경대학교 공과대학 금속공학과) ;
  • 이병우 (부경대학교 공과대학 금속공학과) ;
  • 이문용 (성우금속(주), 기술연구소) ;
  • 이규현 (성우금속(주), 기술연구소) ;
  • 김태일 (성우금속(주), 기술연구소)
  • Published : 1998.12.31
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Abstract

The effects of retained austenite and carbon content in the retained austenite on the tensile strength-elongation balance and spot weldability of TRIP high strength steel sheet have been investigated. The retained austenite of granular type increased with increasing intercritical annealing and austempering temperature, and film type was increased with the increase of austempering time. The volume fraction of retained austenite increased with decreasing intereritical annealing temperature, and the maximum value was obtained at austempering temperature of $400^{\circ}C$. The values of tensile strength-elongation balance increased with decreasing intercritical annealing temperature and maximum value was obtained at austempering temperature of $400^{\circ}C$. The maximum value of tensile strength-elongation balance was obtained at a retained austenite content of about 12%. Tensile shear strength of the specimens with retained austenite was higher than that of the normalizing specimens. With increasing welding current and time, the tensile shear strengh and nugget diameter increased, while nugget thickness showed the peak value and then decreased. The optimum range of welding condition at the given welding pressure of 350kgf was 7~11kA and 10~15 cycles.

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Acknowledgement

Supported by : 포항종합제철주식회사