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Effects of Phosphorus and in-situ Post-heat Pulse Conditions on Resistance Spot Weldability of High Si DP980 Steel Sheet
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  • Journal title : Journal of Welding and Joining
  • Volume 33, Issue 6,  2015, pp.21-26
  • Publisher : The Korean Welding and Joining Society
  • DOI : 10.5781/JWJ.2015.33.6.21
 Title & Authors
Effects of Phosphorus and in-situ Post-heat Pulse Conditions on Resistance Spot Weldability of High Si DP980 Steel Sheet
Choi, Du-Youl;
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 Abstract
Recently, application of UHSS(Ultra High Strength Steels) whose tensile strength is over 1000MPa to car body structure are growing due to great needs for light weighting and improved crash worthiness. However, their poor weldability is one of obstacles to expand selecting to car body. In this study, effect of Phosphorus contents on resistance spot weldability of high elongation DP980 steel whose Si content is over 1% was investigated. The cross tension strength (CTS) was decreased showing partial interface fracture as Phosphorus content increase because of solidification segregation of Phosphorus. In order to improve resistance spot weldability by modification of welding condition, in-situ post-weld heating pulse was introduced after main pulse. The optimum cooling time between main and post pulse and post-pulse current condtion were determined through FEM welding simulation and DOE tests. The CTS was increased about 1.5 time showing plug fracture. The decrease of Phosphorus segregation was found to be a major reason for weld ductility and CTS improvement.
 Keywords
Ultra high strength steel;Dual phase steel;Cross tension strength;Resistance spot welding;
 Language
Korean
 Cited by
 References
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