|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||High Performance Steels
||Multi-stage Welding Cycles for Resistance Spot Welding of Advanced Martensitic Steels
||Emmitt Fagerstrom, Benjamin Hilpert, Holger Schubert, Bharat Balasubramanian, Luke Brewer
|On-Site Speaker (Planned)
This research investigates the influences of in-process heat treatment on resistance spot welding (RSW) of next generation martensitic steels for automotive body applications. RSW is used extensively in the automotive industry, but with the advent of newer high strength steels (ultimate strengths > 1200 MPa), the standard process cycle cannot always achieve acceptable weld quality. The martensite formed by the high cooling rates associated with RSW can be ameliorated by the use of pre- or post- weld current pulses during joining. In this study, we have systematically investigated multi-stage welding cycles for RSW of a fully-martensitic 1500 MPa steel. The mechanical properties are evaluated through lap-shear tensile testing and microhardness testing. While initial microscopy does not show large differences in weld microstructure, the lap-shear results show a significant, positive increase in mechanical energy absorbed during joint failure. Further connections between martensite content and weld mechanical properties will be discussed.
||Iron and Steel, Joining, Mechanical Properties