关键词: 焊合, 挤压, 空洞闭合

Abstract: During the divided flow extrusion process of aluminum alloy tube, the metal streams in welding chamber undergoes a solid welding process, which results in the formation of longitudinal weld seams in the whole length of extruded profile. Generally, the weld seams are the weakest part of extruded tubes, so seam welding quality is one of the key problems for aluminum alloy extruded tube working under high pressure conditions. Based on theory of the extrusion forming process and meso-plasticity, evolution mechanism of the voids at the seaming welding plane during the extrusion process is studied. A mathematic model which is able to describing the void closure process under macro stress field is established. Constitutive model of the material at the welding position was established and then an expression of the void closure process is deduced according to the process of the extrusion welding process. Further, physical simulation is done to validate the model and key factors affecting the welding status is examined. This study provides a quantitative means of evaluating the seam welding quality.

Key words: extrusion, seam welding, void closure