Abstract: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.

Key words: continuous extrusion; 6063 Al alloy; extrusion speed; welding performance