Comparative Study on Welding Characteristics of Laser-CMT and Plasma-CMT Hybrid Welded AA6082-T6 Aluminum Alloy Butt Joints

Abstract

Laser-CMT (Cold Metal Transfer) and plasma-CMT hybrid welding are two promising alternative joining technologies for traditional Metal-Inert-Gas (MIG) welding of the aluminum alloy joints in the high speed trains manufacturing industry. In this work, a comparative study on the weld formation, microstructure, micro-hardness, and mechanical properties of the butt joints in the two welding methods was conducted. The results indicate that the overall quality of the laser-CMT and plasma-CMT welds were good, especially of the laser-CMT hybrid weld, and the laser-CMT hybrid welding process needed a lower heat input. The width of the partially melted zone of the laser-CMT hybrid weld was narrower than that in the plasma-CMT hybrid weld. Micro-hardness test results show that two distinct softening regions were identified in the heat affected zone, and the micro-hardness values of each zone in the laser-CMT hybrid weld were lower than that in the plasma-CMT hybrid weld. The tensile strength of the laser-CMT hybrid welded joints was higher than that of the plasma-CMT hybrid welded joints, which could reach up to 79.4% and 73.7% of the base materials, respectively. All the fractures occurred in the softening region and exhibited a ductile shear fracture with a shear angle of approximately 45°. The fractographs manifested that the laser-CMT and plasma-CMT hybrid welded joints presented ductile fracture and ductile-brittle fracture features, respectively.

A Review of Numerical Simulation of Laser–Arc Hybrid Welding

“…In LAHW, welding parameters (such as laser power, arc current, and wire spacing), heat source parameters, and process parameters (such as shielding gas flow rate and welding speed) have great influence on laser-arc interaction, and help to achieve the control of weld formation, welding process stability, and welding defects and other purposes [55][56][57]. Gas hole defect is the key research object of welding-related subjects because it can reduce the effective working section of the weld seam, lead to stress concentration, and then reduce the mechanical properties of the weld seam.…”

Comparative Study of Laser-Arc Hybrid Welding for AA6082-T6 Aluminum Alloy with Two Different Arc Modes

“…By comparison, the width of the heat-affected zone of the LPMHW joint was larger than that of the LCHW joint. It was found that there were two softening regions in the affected zone of the two joints: one was in the partially melted zone because of the loss of strengthening alloying elements in this area [37,38], and the other was at a distance away from the fusion line due to the strengthening phases (β") being dissolved and substantially decreased in this area [39]. Furthermore, the second softening region was more prominent in the arc zone, and was also wider for the LPMHW joint compared with that of the LCHW joint.…”

Investigation on Microstructure and Tensile Properties of High‐Strength AA2014 Aluminium Alloy Welds Joined by Pulsed CMT Welding Process

“…e light combat aircraft interstage skin and the automotive wheel are made from this alloy. e main problems encountered in welding high-strength agehardened Al-alloys, including AA2014, are cracking in weld metal and partially melted zone, porosity, and alloy segregation which constrain the fusion welding of AA2014 aluminium alloy (Babu et al, [1][2][3][4][5][6][7][8][9]). Hence, novel methods have been developed and commercialized over few decades.…”