ABSTRACT
High-Mn twinning-induced plasticity (TWIP) steels have been proposed to meet higher passenger safety and crash-safe vehicle frame requirements demanded by the automotive industry. The corrosion behaviour of welded Fe–30Mn–5Al–0.5C–6Cr TWIP steel using the resistance-spot-welding (RSW) technique was studied. Welds showed a microstructure consisting of primary austenite dendrites and interdendritic δ-ferrite in both fusion zone (FZ) and base metal (BM), which is in agreement with an austenitic-ferritic (AF) solidification mode. The results reveal that the refinement of the microstructure in the weld region does not significantly affect the corrosion resistance of this region, having a low corrosion current density of the order of 1 μA cm–2. It was concluded that Cr-rich second phase particles along the austenite/δ-ferrite interface can lead to Cr-depleted zones, increasing pitting corrosion susceptibility. It was found that the minimum Cr content at the Cr-depleted zones is nearly independent of the δ-ferrite volume fraction.
Acknowledgements
The authors express their gratitude to the CENIM-CSIC for the facilities given to develop this investigation. J. Ress and D.M. Bastidas acknowledge funding from The University of Akron, Fellowship Program FRC-207367. J.M. Bastidas acknowledges Project MAT2015-71761-R from the MINECO/FEDER, Spain, for financial support.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form part of an ongoing study.