Abstract
The T-joints of medium-thick 6082 Al-alloy plates created by dual pulsed gas metal arc welding (P-GMAW) and bilateral synchronous welding were investigated to improve weld quality using the adaptive deposition method, which calculates the minimum amount of deposition according to the welding condition, groove size, and cross-sectional area, effectively reducing the heat input and deformation of the welds on the basis of weld filling. The optimized linear energy with a wire feed speed (WFS) of 9.5 m/min can ensure a well-formed weld with a complete root fusion, and high-quality T-joint welds were obtained both in root openings of 0 mm and 1 mm. The biggest penetration was 4 mm, which was four times more than that of the result from a single torch welding process. When the distance between the two welding torches exceeded 20 mm, the molten pool was completely separated, and process pores were observed in the unfused root zone. Influenced by the thermal cycles in asymmetric welding, the hardness distribution changed: the width of the softer zone at the base plate with the fore arc was smaller than that zone with the rear arc. Furthermore, dual P-GMAW bilateral synchronous welding with an asymmetric heat source can further reduce the deformation of the welded joint by about 20% compared to that of symmetric welding.
Highlights
Published: 8 November 2021Owing to its excellent performances such as high specific strength, great stress corrosion resistance, good weldability and formability, Al-alloy and other advanced materials have become the preferred alloys for automobiles and rail transit [1,2,3,4]
When wire feed speed (WFS) increased to 10 m/min, the average current during this process was about 300A, and the droplet transfer frequency increased by 39% in comparison with that of 6 m/min
T-joint welding for medium-thick Al-alloy plates by dual pulsed gas metal arc welding (P-gas metal arc welding (GMAW)) bilateral synchronous welding using the adaptive deposition method has the advantages of reduced deformation, easy operation, and higher quality; this technology will be more suitable to medium-thick plate welding in industry
Summary
Owing to its excellent performances such as high specific strength, great stress corrosion resistance, good weldability and formability, Al-alloy and other advanced materials have become the preferred alloys for automobiles and rail transit [1,2,3,4]. T-joints of aluminum alloy fabricated by dual laser bilateral synchronous welding have been extensively studied [9,10,11,12] It can reliably achieve high-quality symmetrical welding compared with traditional welding processes [13,14]. The double-sided arc welding process has been adopted to join light metal alloy with improved welding quality in comparison with conventional processes, as reported by Shen et al [5] Conventional processes in this part are the multi-pass welding, and the double side welding is used to improve the weld efficiency while ensuring that the joint does not have misalignment and complete penetration [8]. High-quality welds can be obtained by the above method, there are problems: the melted metal only fills the groove, the fusion is poor or not fused, and deformation of the welded plates is severe due to heat input during the multi-layer and multi-pass welding process. Al-alloy plates, and the results and conclusion are on the basis of the technological and theoretical foundation for T-joint welding of a medium-thick plate
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