铝合金双面同步平-仰焊接头成形机理与力学性能

采用双面同步平-仰焊工艺,对8 mm厚5083铝合金进行试验研究,分析了熔池的成形机理,并测试了接头的力学性能.结果表明,工件熔透时形成“公共熔池”,当破坏力大于维持力时,熔池液面下凹,下凹程度随热输入的增大而增大,弯曲液面产生附加压力,压力值与液面的凹陷程度成正比,最终熔池受力达到平衡,形成上凹下凸的“倒拱桥”形接头;双面同步平-仰焊的熔化效率达到了17.29%,远高于单面弧焊的2.20%;接头的平均抗拉强度与断后伸长率分别为275.14 MPa和14.73%,达到母材的90.70%和53.18%.

Shaping mechanism and mechanical properties of aluminum alloy joint by double-sided synchronization downhand-overhead welding

Double-sided synchronization downhand-overhead welding (DSSDOW) of 5083 aluminum alloy with thickness of 8mm was conducted. The shaping mechanism of molten pool was analyzed, and the mechanical properties of joints were tested. The results show that "common pool" formed when the workpiece was completely penetrated. The depression of molten pool began when the collapsing force was larger than the maintaining force, and the extent of depression increased with the increase of heat input. The flexure fluid level produced additional pressure which was proportional to the extent of depression. The force in weld pool reached equilibrium finally. It meants the joint with concave-up convex-down shape formed, which was like an inverted arch bridge. The melting efficiency of DSSDOW was up to 17.29%, more than 2.20% of single side arc welding. The average tensile strength and elongation of the resultant joints were 275 MPa and 14.73%, which were 90.7% and 53.18% of those of base metal, respectively.