Effect of Heat Input on Microstructure and Mechanical Properties of Joints Made by Bypass-Current MIG Welding–Brazing of Magnesium Alloy to Galvanized Steel

• Published in: Acta metallurgica sinica : English letters Vol. 27; no. 6; pp. 1038 - 1045
• Main Authors: Miao, Yugang, Wu, Bintao, Xu, Xiangfang, Han, Duanfeng
• Format: Journal Article
• Language: English
• Published: Heidelberg The Chinese Society for Metals 01-12-2014; Springer Nature B.V
• Subjects: Aluminum; Bypasses; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Friction stir welding; Galvanized steel; Galvanized steels; Galvanizing; Gas flow; Gas metal arc welding; Intermetallic compounds; Iron; Lap joints; Magnesium alloys; Magnesium base alloys; Materials Science; Mechanical properties; Metallic Materials; Metallurgy; Microstructure; Nanotechnology; Organometallic Chemistry; Oxidation; Scanning electron microscopy; Spectroscopy/Spectrometry; Steels; Tribology; Joint characteristics; Interface analysis; Bypass-current MIG welding–brazing; Dissimilar metals
• ISSN: 1006-7191; 2194-1289
• DOI: 10.1007/s40195-014-0118-3

Experiments were carried out with bypass-current MIG welding–brazing of magnesium alloy to galvanized steel to investigate the effect of heat input on the microstructure and mechanical properties of lap joints. Experimental results indicated that the joint efficiency tended to increase at first and then to reduce with the increase of heat input. The joint efficiency reached its maximum of about 70% when the heat input was 155 J/mm. The metallurgical bonding between magnesium alloy and steel was a thin continuous reaction layer, and the intermetallic compound layer consisted of Mg–Zn and slight Fe–Al phases. It is concluded that bypass-current MIG welding–brazing is a stable welding process, which can be used to achieve defect-free joining of magnesium alloy to steel with good weld appearances.