Interactive effects of porosity and microstructure on strength of6063 aluminum alloy CMT MIX + Synchropulse welded joint
(1. School of Iron and Steel, Soochow University, Suzhou 215002, China;
2. School of Mechanical and Transportation, Southwest Forestry University, Kunming 650224, China;
3. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China)
2. School of Mechanical and Transportation, Southwest Forestry University, Kunming 650224, China;
3. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China)
Abstract: The porosity, pore size and softening of 6063 aluminum alloy CMT MIX + Synchropulse welded joint with different welding speeds were studied. The results show that with the increase of welding speed (from 55 to 65 cm/min), the porosity increases dramatically (from 0.1% to 3.9%) and large pores (341.1 μm) appear. The pore size distributions are mainly concentrated at 87.8 and 20.6 μm in the joints produced from weld speeds of 65 and 55 cm/min, respectively. The dissolution and transformation of the β′′ phase in the base metal (BM) result in a significant softening of both the fusion zone and heat-affected zone, and the latter was more serious. The effects of welding speed on the average tensile strength of the full penetration welded joints are minor, which was about 155 MPa (67.4% that of the BM).
Key words: cold metal transfer; aluminum alloy; pore; microstructure; mechanical properties