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Enhanced mechanical properties of martensitic stainless steels resistance spot welds enabled by in situ rapid tempering

Pouranvari, M ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1080/13621718.2019.1641962
  3. Publisher: Taylor and Francis Ltd , 2020
  4. Abstract:
  5. Resistance spot weldability of martensitic stainless steels is impaired by the formation of brittle martensite in the fusion zone (FZ). In this paper, in situ rapid tempering via applying a second pulse current after a first melting/solidification pulse during resistance spot welding of AISI 420 martensitic stainless steel sheets was used as a pathway to enhance the toughness of the FZ. By using proper second pulse conditions, the FZ with reduced hardness can be generated which is featured by a decomposed martensitic structure with nano-sized carbide precipitations. The improved toughness as a consequence of this modified microstructure resulted in remarkable enhancement of the peak load and energy absorption of the spot welds compared to the single-pulse welds. © 2019, © 2019 Institute of Materials, Minerals and Mining. Published by Taylor & Francis on behalf of the Institute
  6. Keywords:
  7. In situ rapid tempering ; Second pulse time ; Carbides ; Energy absorption ; Mechanical properties ; Spot welding ; Tempering ; Welds ; Aisi 420 martensitic stainless steels ; Martensitic structures ; Nano-sized carbides ; Peak load ; Pulse time ; Resistance spot weld ; Resistance spot welding ; Second pulse currents ; Martensitic stainless steel
  8. Source: Science and Technology of Welding and Joining ; Volume 25, Issue 2 , 2020 , Pages 119-126
  9. URL: https://www.tandfonline.com/doi/abs/10.1080/13621718.2019.1641962?journalCode=ystw20