Effects of extrusion speed of continuous extrusion with double billets on welding performance of 6063 Al alloy

挤压速度对双坯料连续挤压6063铝合金焊合性能的影响

During continuous extrusion,the welds were formed at the confluence of two billets.Influences of extrusion wheel rotational speed on micromorphology and properties of welds of 6063 Al alloy were investigated through microstructure observation,tensile test,and SEM analyses.Welding parameters were analyzed using finite element simulation.Results indicated that metal welding was remarkably affected by oxide on outer surface of the double billets during continuous extrusion.Degree of oxide breakage on the welding surface increased due to the evident increase in effective strain rate with increasing extrusion speed.The high temperature induced by increased extrusion speed accelerated the formation of metallurgical bonding.A portion of weld seam lines slowly disappeared,and the proportion of the welding interface that failed to reach metallurgical bonding was also gradually reduced.Tensile strength and elongation of the weld specimen increased with the increase of extrusion speed.

在双坯料连续挤压过程中,由于两根坯料汇合而形成挤压焊缝。通过显微组织观察、拉伸试验、扫描电镜研究挤压轮转速对6063铝合金焊缝显微组织形貌和性能的影响,并通过有限元仿真分析焊合参数。结果表明,在连续挤压过程中,坯料外表面的氧化物对金属焊合有显著影响,随着挤压速度的增加,等效应变速率明显增加,造成焊合面上的氧化物的破碎程度增加。提高挤压速度所引起的高温加速焊合界面形成冶金结合,部分焊合线逐渐消失,焊合界面上未达到冶金结合的焊缝所占比例逐渐降低。随着挤压速度的增加,焊缝试样的抗拉强度和伸长率均增大。