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In situ postweld heat treatment of transformation induced plasticity steel resistance spot welds

Sajjadi Nikoo, S ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1080/13621718.2017.1323174
  3. Publisher: Taylor and Francis Ltd , 2018
  4. Abstract:
  5. Transformation-induced plasticity (TRIP) steel resistance spot welds are delicate to low-energy interfacial failure via crack propagation through martensitic fusion zone during cross-tension (CT) loading. This paper addresses the effect of three different types of in situ postweld heat treatment (PWHT) on the mechanical properties of TRIP steel resistance spot welds. Depending on the post weld second pulse current level, three different strengthening mechanisms were found including (i) martensite tempering with reduced hardness, (ii) refining of martensite packets with improved toughness and (iii) nugget re-melting/enlargement combined with possible reduction of grain boundary impurity segregation. All designed in situ PWHTs were enabled to promote pullout failure mode with improved load-bearing capacity and energy absorption capability during CT loading. © 2017 Institute of Materials, Minerals and Mining. Published by Taylor & Francis on behalf of the Institute
  6. Keywords:
  7. Failure mode ; Postweld heat treatment ; TRIP steel ; Failure modes ; Grain boundaries ; Heat resistance ; Heat treatment ; High strength steel ; Martensite ; Martensitic steel ; Martensitic transformations ; Plasticity ; Spot welding ; Steel ; Welds ; Energy absorption capability ; Load-bearing capacity ; Post weld heat treatment ; Resistance spot welding ; Second pulse currents ; Strengthening mechanisms ; Transformation induced plasticity steel ; TRIP-steel ; Resistance welding
  8. Source: Science and Technology of Welding and Joining ; Volume 23, Issue 1 , 2018 , Pages 71-78 ; 13621718 (ISSN)
  9. URL: https://www.tandfonline.com/doi/abs/10.1080/13621718.2017.1323174