中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 8 August 2015 |
（Key Laboratory of Automobile Materials of Ministry of Education,
School of Materials Science and Engineering, Jilin University, Changchun 130025, China）
Abstract:The joining of Mg alloy to steel was realized by metal inert-gas arc welding, and the weld thermal cycle characteristics and Mg-steel joints were investigated. The results show that the temperature distribution in the joints is uneven. Mg alloy welds present a fine equiaxed grain structure. There exists a transition layer consisting mainly of AlFe, AlFe3 and Mg(Fe, Al)2O4 phases at Mg/steel interface, and it is the weakest link in Mg-steel joints. The welding heat input and weld Al content have the significant effect on the joint strength. The joint strength increases with increasing the heat input from 1680 J/cm to 2093 J/cm, due to promoting Mg/steel interface reaction. When weld Al content is increased to 6.20%, the joint strength reaches 192 MPa, 80% of Mg alloy base metal strength. It is favorable to select the suitable welding heat input and weld Al content for improving joint strength.
Key words: AZ31B Mg alloy; Q235 steel; metal inert-gas arc welding; dissimilar metal joining
