Liquid Metal Embrittlement of Galvanized TRIP Steels in Resistance Spot Welding

Abstract

Liquid metal embrittlement (LME) in Zn-coated steels is a serious issue in automotive design. The risk of rising LME surface cracks in resistance spot welding (RSW) of Zn-coated high strength steels has triggered significant research activities across the globe. This paper presents a state-of-the-art review of the various phenomena and issues related to LME during RSW. Various aspects of LME surface cracks have been described in this review, focusing on the macro- and microscopic features of LME, spot weld cracks, the sensitivity of the LME cracks towards surface locations, welding conditions, and susceptibility to high strength and galvanized steels. We also focus on the effects of various processing factors, such as temperature, stress, microstructure, and the nature of the galvanized layer, related to studies with actual spot welds LME cracks. Finally, we summarize the possible mechanisms of embrittlement and the remedies for minimizing LME cracks, with suitable guidelines to suppress surface cracks during RSW.

An Investigation on Laser Welding Parameters on the Strength of TRIP Steel

“…Furthermore, the transformation induced plasticity (TRIP) steels with enormous strength and ductility properties has emerged as a new generation material to replace AHSS and thus to meet the requirements of automobile industries [19]. The base metal microstructure of TRIP steel is mainly constituted with a ferrite matrix along with trace amounts of martensite, bainite, and confined austenite alloys [20].…”

Effect of Silica Content on Mechanical and Microstructure Behaviour of Resistance Spot Welded Advanced Automotive TRIP Steels

“…However, TRIP high-strength steel has a higher C, Mn, Si, Al, and other alloying elements with better weldability than other steels [6], [7]. In recent years, resistance spot welding is the primary welding method used to join the TRIP steels for automobile structure application [8]. Many researchers have studied the pulsed welding and heat treatment on TRIP steels after welding [9,10].…”

Numerical Prediction of Stresses at High Temperature of 3rd Generation Advanced High Strength Steels During Resistance Spot Welding - Liquid Metal Embrittlement Risk Assessment. Methodology to Create and Validate a Reliable and Robust Numerical Material Card

“…All these steps are needed to create a robust spot weld. However, during resistance spot welding of 3rd generation Advanced High Strength Steel sheets with zinc coating, the Liquid Metal Embrittlement phenomenon may occur [4,5]. This phenomenon corresponds to the penetration of liquid zinc of the coating in the grain boundaries of the steel at high temperature [6,7], in a zone under high internal stress.…”