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Metals and Materials International

, Volume 25, Issue 1, pp 179–192 | Cite as

Influence of heat-treated Al–Si coating on the weldability and microstructural inhomogeneity for hot stamped steel resistance nut projection welds

  • Eun-Joon Chun
  • Sung-Sang Lim
  • Young-Tae Kim
  • Ki-Sung Nam
  • Young-Min Kim
  • Young-Whan Park
  • Siva Prasad Murugan
  • Yeong-Do ParkEmail author
Article
  • 160 Downloads

Abstract

Resistance nut projection weldability of Al–Si coated hot stamped steel (HSS) was investigated under the viewpoint of weldable current range and joint strength (pull-out load). The microstructural inhomogeneities in the welds were also studied in order to elucidate the factors affecting the joint strength of the welds. The weldability of the given Al–Si coated HSS was compared with the weldability of an identical HSS without the Al–Si coating (Al–Si coating was polished out) and Zn coated dual phase steel. The weldable current range of Al–Si coated HSS was found to be narrower than that of the other materials. Furthermore, the average pull-out load within the weldable current range of the Al–Si coated HSS was the lowest among the three materials. The reason for poor weld mechanical property of the Al–Si coated hot-stamped steel was attributed to the microstructural inhomogeneities such as unmixed Al–Si coating layer at the edge of the nugget and the second phase Fe3(Al, Si) intermetallic compound. The formation of Fe3(Al, Si) phase was attributed to the solidification segregation of Al and Si during the weld solidification and was confirmed with the numerical analysis of solidification segregation.

Keywords

Welding Nut projection Mechanical property Hot stamped steel Al–Si coating Segregation 

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Copyright information

© The Korean Institute of Metals and Materials 2018

Authors and Affiliations

  • Eun-Joon Chun
    • 1
  • Sung-Sang Lim
    • 2
  • Young-Tae Kim
    • 3
  • Ki-Sung Nam
    • 4
  • Young-Min Kim
    • 5
  • Young-Whan Park
    • 6
  • Siva Prasad Murugan
    • 7
  • Yeong-Do Park
    • 7
    Email author
  1. 1.Busan Machinery Research CenterKorea Institute of Machinery and MaterialsBusanRepublic of Korea
  2. 2.Department of Marine Equipment EngineeringKorea Maritime and Ocean UniversityBusanRepublic of Korea
  3. 3.Sheet Metal Development TeamHyundai Motor R&D CenterHwaseong-siRepublic of Korea
  4. 4.Advanced Technology TeamSungwoo Hitech Co. Ltd.Yangsan-siRepublic of Korea
  5. 5.Joining R&D GroupKorea Institute of Industrial TechnologyIncheonRepublic of Korea
  6. 6.Department of Mechanical EngineeringPukyong National UniversityBusanRepublic of Korea
  7. 7.Department of Advanced Materials EngineeringDong-Eui UniversityBusanRepublic of Korea

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