Issue 53

Y. Lu et alii, Frattura ed Integrità Strutturale, 53 (2020) 325-336; DOI: 10.3221/IGF-ESIS.53.25 329 Figure 2: Anti-deformation treatment diagram R ESULTS AND DISCUSSION A6061-T6 aluminum alloy and DP590 steel commonly used in the automotive industry are used as test plates. So in this paper, AA6061-T6 aluminum alloy and DP590 steel are used as test plates, and ER4043 (AlSi5) with a diameter of 1.2mm is used as a filler wire. An aluminum plate having a thickness of 1 mm, 1.2 mm, 1.5 mm, and 2 mm and a steel plate having a thickness of 1.2 mm are cut into a sample having a length × width of 150 mm × 50 mm by a wire cutter. Before the test, the aluminum plate is polished with sandpaper to remove the oxide film, and then the surface of the steel plate is cleaned with an acetone solution to remove stains, grease, and the like on the surface. The test adopts the lap joint method, the upper layer is aluminum plate and the lower layer is steel plate., and the lap joint amount is 150 mm × 10 mm. Fig. 3 is a schematic view of CMT seam welding of aluminum-steel sheet. Figure 3: Illustration of seam welding of AA6061-T6/DP590 sheet The welding equipment required for this test includes the TPS4000 CMT welder from Fronius, welding torch and KUKA robot arm. The welding torch and the surface of the welded part are at an angle of 45°, and the aluminum-steel sheet is welded in a single pass. High purity argon was selected as the shielding gas in the test and operated at a flow rate of 15 L/min. During the aluminum-steel CMT seam welding test, the length and width of the aluminum plate and the steel plate were kept unchanged, and 16 groups of tests were carried out according to the five-factor and four-level orthogonal table. The wire feed speed, welding speed, arc correction and aluminum plate thickness were selected as four factors of orthogonal test. The deformation of aluminum-steel sheet was used as the evaluation index of CMT seam welding quality of aluminum-steel. The welding test factor level table is shown in Tab. 1. It was observed that the aluminum plate side showed warping deformation at the middle and low sides after welding. Select the middle point B of point A and point C on the side of the aluminum plate as the measurement point, and then the welding deformation is the height difference between point B before welding and point B after welding. The measuring point is shown in Fig. 3. The coordinates of point B before and after welding is measured by a binocular stereoscopic measuring point device as shown in Fig. 4, and the height difference was calculated manually as the amount of welding deformation. Welding parameters analysis The orthogonal test results of aluminum-steel CMT welding are shown in Tab. 2. In this paper, the deformation of 16 specimens in Tab. 2 was taken as the reference sequence. The corresponding horizontal value-wire feed speed, welding speed, arc correction, and aluminum plate thickness were used as comparison sequence. The data were substituted into the above formula to calculate the correlation degree of each CMT welding parameter to the welding deformation A