Investigation on Resistance Spot Welding of TWIP Steel Sheets. Issue 12 (14th March 2015)

• Record Type: Journal Article
• Authors: Russo Spena, Pasquale; De Maddis, Manuela; Lombardi, Franco; Rossini, Matteo
• Is Part Of: Steel research international. Volume 86:Issue 12(2015:Dec.)
• Page Start: 1480
• Page End: 1489
• Publication Date: 2015-03-14
• Subjects: resistance spot welding -- welding parameters -- TWIP steel -- tensile shear strength -- microstructure, fractograph; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.201400336
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : A widespread usage of new advanced high strength TWIP steels in the automotive industry is conditional on proper assembly operations by welding. Therefore, the effects of the main important process parameters on the mechanical and microstructural properties of resistance spot welded TWIP sheets are examined here. The welding parameters used were the welding current, clamping force, and welding time. An L‐9(3 3 ) orthogonally array was used to design the experimental tests. The mechanical response of the welded joints was assessed by tensile shear tests and Vickers microhardness measurements. The effects of the welding parameters on the fracture mode of the tensile shear specimens were also investigated. Some combinations of the welding process parameters guarantee acceptable tensile shear strengths for the automotive industry. The tensile shear samples mainly failed by interfacial fracture mode, while partial thickness with pull out fractures were observed in the samples when a high welding current and clamping force were used. Improper clamping force and welding current promoted excessive metal expulsions and, in turn, the formation of welding defects in the weld spots. Abstract : New austenitic high‐manganese TWIP steels have been proposed for the fabrication of car‐body components due to their excellent combination of strength and ductility . A widespread usage of TWIP steel grades is conditional on the employment of resistance spot welding to assemble car body components. For this reason, this work aims at investigating the effect of welding parameters on the mechanical and microstructural responses of TWIP weld spots.