Influence of filler wire and wire feed speed on metallurgical and mechanical properties of MIG welding–brazing of automotive galvanized steel/5754 aluminum alloy in a lap joint configuration

Abstract

In this research, the galvanized steel with thickness of 2 mm was joined to the 5754 aluminum alloy with thickness of 3 mm by the cold metal transfer MIG welding-brazing process. The effect of the filler wires (AlSi 3 Mn, AlSi 5 , and AlSi 12 ) and wire feed speeds (4.7, 5, and 5.3 m/min) on metallurgical and mechanical properties have been discussed. According to the experimental results, thickness of intermetallic compound (IMC) layer which was formed along the interface during the MIG welding-brazing was varied by changing of parameters. In addition, the results indicated that by increasing of the wire feed speed, the thickness of IMC layer at first decreased and then increased. Results indicated that the maximum thickness variation of IMC layer belonged to the AlSi 12 filler wire and the best consistent tensile strength was produced with AlSi 3 Mn filler wire with an average value of 188 N/mm 2 . Observation of the failed specimens indicated two types of failure modes under the tensile load, including the fractures occurred in HAZ of aluminum and the fractures occurred near IMC layer.

Laser and Gas Metal Arc Based Dissimilar Joining of Automotive Aluminium Alloys and Steel Sheets - A Review

“…The authors found phase layer thickness around 1.3 ~ 2 μm with maximum joint strength of 73 MPa for aluminium to GA sheets 45,46) , while joining with GI sheet exhibited higher joint strength of 210 MPa with phase layer thickness of 0.8 ~ 4.5 μm 7) . Milani et al 47) examined the influence of different filler wires -AA4043, AA4047 and Al-Si3-Mn -on joining of 2 mm thick AA5754 alloy and 3 mm thick GI steel sheets by CMT process. The maximum joint strength was found to be around 188 MPa with the Al-Si3-Mn1 filler wire 47) .…”

“…Milani et al 47) examined the influence of different filler wires -AA4043, AA4047 and Al-Si3-Mn -on joining of 2 mm thick AA5754 alloy and 3 mm thick GI steel sheets by CMT process. The maximum joint strength was found to be around 188 MPa with the Al-Si3-Mn1 filler wire 47) . In another study, Chang et al 48) investigated the effect of AA2319 (Al-6%Cu) and AA5087 (Al-5%Mg) filler wire on joint quality in joining of AA6082 and ultra-high strength steel, both of 4 mm in thickness, by GMA process.…”

Review of Aluminum-To-Steel Welding Technologies for Car-Body Applications

“…In particular, Al-5% or 12% Si or Zn-15% Al are commonly used filler alloys. Dong et al [9], Su et al [10] and Milani et al [11] have shown that a relatively high amount of Si in the filler wire can reduce the diffusion of iron in molten aluminum, resulting in a reduction of the thickness of the IMC layers, and especially of the Al 5 Fe 2 layer.…”

Mechanical and microstructural characterization of cold metal transfer (CMT) spot aluminium-steel weld-brazed joints

“…8 Several studies have reported the miraculous role of Si in preventing the excessive formation of hard and brittle Fe-Al binary intermetallic phases. 27,28 Figure 6 shows the microstructural evolution in the fusion zone (deposited Al-Si-Mn filler) and intermetallic compound layer at the interface of deposited filler-steel. The fusion zone consisted of α-Al matrix and Al-Si eutectic phases at its grain boundaries.…”