A Novel Shim-Assisted Resistance Spot Welding Process to Improve Weldability of Medium-Mn Transformation-Induced Plasticity Steel
- University of Science and Technology, Beijing, School of Metallurgical and Ecological Engineering (China)
- Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics (China)
- General Motors Global Research & Development Center, China Science Lab (China)
Medium-Mn transformation-induced plasticity steels have great potential to significantly reduce vehicle weight and improve fuel economy due to their outstanding combination of high strength and excellent ductility. One bottleneck to the application is their poor weldability resulting from their high Mn contents. In this paper, three resistance spot welding set-ups, including no shim, an interstitial-free steel shim at the faying interface (shim-in) and shims against the electrodes (shim-out), were incorporated to investigate the weldability of Fe-7Mn-0.14C medium-Mn steel. Tensile-shear, cross-tension, and microhardness tests were used to evaluate the mechanical properties of the welds. Experimental results demonstrated that the failure mode of the welds transitioned from the interfacial fracture in the case of no shim to the desired nugget pull-out fracture in the shim-out set-up, resulting in dramatical improvements in both peak loads and their corresponding extensions during the tensile-shear and cross-tension tests. In contrast, the shim-in set-up made no improvement. What can contribute to such improvement was then discussed on the basis of observed morphologies and microstructures of welds.
- OSTI ID:
- 22933584
- Journal Information:
- Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science, Vol. 50, Issue 1; Other Information: Copyright (c) 2019 The Minerals, Metals & Materials Society and ASM International; Article Copyright (c) 2018 The Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1073-5615
- Country of Publication:
- United States
- Language:
- English
Similar Records
Friction Stir Spot Welding (FSSW) of Advanced High Strength Steel (AHSS)
In Situ and Post-Mortem Characterizations of Ultrasonic Spot Welded AZ31B and Coated Dual Phase 590 Steel Joints