Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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Microstructures and Hardness of DISK Laser Welds in Al-Si Coated Boron Steel and Zn Coated DP Steel

Al-Si Coated Boron Steel과 Zn Coated DP Steel 이종금속의 DISK Laser 용접부 미세조직과 경도

  • An, Yong-Gyu (National Core Research Center, Pusan National University) ;
  • Kang, Chung-Yun (National Core Research Center, Pusan National University) ;
  • Kim, Young-Su (Technical Research Team, SUNGWOO HITECH) ;
  • Kim, Cheol-Hee (Advanced Joining Technology Team, Korea Institute of Industrial Technology) ;
  • Han, Tae-Kyo (Technical Research Lab, POSCO)
  • 안용규 (부산대학교 하이브리드소재솔루션 국가핵심연구센터(NCRC)) ;
  • 강정윤 (부산대학교 하이브리드소재솔루션 국가핵심연구센터(NCRC)) ;
  • 김영수 (성우하이텍 기술연구소) ;
  • 김철희 (한국생산기술연구원 정밀접합팀) ;
  • 한태교 (포스코 기술연구소)
  • Received : 2010.10.28
  • Accepted : 2011.01.04
  • Published : 2011.02.28
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Abstract

Al-Si coated Boron steel and Zn coated DP steel were welded using DISK laser and the microstructure and hardness of the weld were investigated. Full penetration was obtained, when the welding speed was lower than 4m/min. In the specimen welded with laser power of 3 kW and welding speed of 2 m/min, the hardness was the highest in the heat affect zone in the boron steel (HAZ-B) and that of the heat affect zone in the DP steel (HAZ-D) was lower than HAZ-B. The hardness of fusion zone was in between those of HAZ-B and HAZ-D. The decreased hardness from each HAZ to base metal(BM) could be explained that ferrite contents increases when access to the BM. The variation of hardness in the welds could be explained by the difference of microstructure, that is, full martensite in HAZ-B, mixture of martensite and bainite in the fusion zone, and the mixture of martensite, ferrite and bainite in HAZ-D.

Keywords

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