Study On Welding-Brazing Of Dissimilar Metals Between Steel Stud And Aluminum Alloy

In this paper, weldability of dissimilar metal between Q235 steel stud and 6061 aluminum alloy was researched through high-frequency induction welding-brazing and CMT welding-brazing. The right welding norms and good performance of weld joints were got respectively. Welding process parameters were discussed for welding performance and mechanical properties. Combined with the discussion and analysis of aluminum and steel welding, welding-brazing mechanism of steel stud and aluminum sheet were researched.When high-frequency induction welding-brazing, Al-Si solder was used. When the induction welding time 150s, the induced current 900A, weld appearance was good. A good welding joint, which has a certain mechanical properties, could be got; When CMT welding-brazing, hot-dip galvanizing is used as a middle-tier. When the welding current to 210A and the arc-length correction rate at 10%, a good welding joint could be got.The mechanical performance testing showed that:By means of high frequency induction welding-brazing technology and CMT welding-brazing technology for steel stud and aluminum welding, the shear strength of high-frequency induction welding-brazing joints reached 65.32MPa; The shear strength of CMT welding-brazing welded joints was up to 76.34MPa.Means of metallographic microscope, SEM, ED AX were used to observe and analysis the microstructure of weld joints. The results show that, through induction welding-brazing, the joint organization is composed by three regions, such as the intermetallic compounds of Fe2Al5 and FeA3, Al-Si eutectic phase,α-Al solid solution. The thickness of Intermetallic compounds is about 10μm, which is primarily associated with the spread of Fe atom. With the increase of welding time or the induced current, the diffusion of Fe will be more serious, the formation of intermetallic compounds will be thicker. When the steel stud and aluminum are welded by CMT welding-brazing, intermetallic compounds which has the thickness of 20μm is generated between the aluminum and steel. The intermetallic compound mainly composed of Fe2Al5 and FeAl3; when galvanized steel stud and aluminum are welded, due to the diffusion of Fe atoms and Al atoms, small amount of intermetallic compounds generate in the middle of galvanized layer. The intermetallic compounds have a certain impact on the performance of the joints.