The present study is aimed to compare the microstructure characteristics and mechanical properties of AA6082 in T6 condition of tubular joints fabricated by tungsten inert gas welding （TIG） and metal inert gas weldi...The present study is aimed to compare the microstructure characteristics and mechanical properties of AA6082 in T6 condition of tubular joints fabricated by tungsten inert gas welding （TIG） and metal inert gas welding （MIG） processes. The effect of welding processes was analysed based on optical microscopy image, tensile testing, and Vickers micro-hardness measurements. The results showed that the tensile strengths of the TIG-welded joints were better than those of the MIG-welded joints, due to the contribution of fine equiaxed grains formation with narrower spacing arms. In terms of joint efficiency, the TIG process produced more reliable strength, which was about 25% higher compared to the MIG-joint. A significant decay of hardness was recorded in the adjacent of the weld bead zone, shown in both joints, related to phase transformation, induced by high temperatures experienced by material. A very low hardness, which was about 1.08 GPa, was recorded in the MIG-weldcd specimens. The extent of the heat-affected-zone （HAZ） in the MIG-welded joints was slightly wider than those of the TIG-welded specimens, which corresponded with a higher heat input per unit length.展开更多
Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anod...Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H 2SO 4 solution. The polarization tests showed that for the as welded joint both the heat affected zone and the weld metal decreased in resistance to corrosion compared with the as received parent material while for the micro plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.展开更多
基金University Science Malaysia (USM) and Malaysia Ministry of Education (MoE) for their technical and financial support
文摘The present study is aimed to compare the microstructure characteristics and mechanical properties of AA6082 in T6 condition of tubular joints fabricated by tungsten inert gas welding （TIG） and metal inert gas welding （MIG） processes. The effect of welding processes was analysed based on optical microscopy image, tensile testing, and Vickers micro-hardness measurements. The results showed that the tensile strengths of the TIG-welded joints were better than those of the MIG-welded joints, due to the contribution of fine equiaxed grains formation with narrower spacing arms. In terms of joint efficiency, the TIG process produced more reliable strength, which was about 25% higher compared to the MIG-joint. A significant decay of hardness was recorded in the adjacent of the weld bead zone, shown in both joints, related to phase transformation, induced by high temperatures experienced by material. A very low hardness, which was about 1.08 GPa, was recorded in the MIG-weldcd specimens. The extent of the heat-affected-zone （HAZ） in the MIG-welded joints was slightly wider than those of the TIG-welded specimens, which corresponded with a higher heat input per unit length.
文摘Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H 2SO 4 solution. The polarization tests showed that for the as welded joint both the heat affected zone and the weld metal decreased in resistance to corrosion compared with the as received parent material while for the micro plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.
