Research on AZ31 Mg alloy/22MnB5 steel pinless friction stir spot welding process and interfacial temperature field simulation

Abstract

This paper discusses the successful welding of AZ31 Mg alloy to 22MnB5 high-strength steel using pinless friction stir welding (P-FSSW) to join dissimilar metals and reduce vehicle weight while maintaining strength and stiffness. P-FSSW eliminates fusion welding defects, ensuring good performance of Mg/steel welds. An orthogonal experimental design was adopted to comprehensively analyze welding parameters for determining the optimum P-FSSW process conditions. The study provides an in-depth examination of the interfacial layer formation between AZ31 Mg alloy and 22MnB5 steel, emphasizing the importance of Al for effective bonding in Mg alloys. Numerical simulation of the welding process's temperature field is verified by thermocouple measurements, confirming result accuracy. The study aims to optimize bonding of dissimilar materials and facilitate interfacial reactions for achieving high-performance welded joints. This comprehensive understanding of the P-FSSW process and interfacial layer formation holds great significance for lightweight construction in the automotive industry, contributing to reduced emissions and improved fuel efficiency.