利用板条CO2激光器,针对Al-Zn-Mg-Cu系7075-T6高强铝合金2.4 mm厚度的板材进行了扫描和填丝焊接实验研究,并对接头机械性能进行了评定。分析了激光功率、聚焦镜焦距、焊接速度、工作气体及焊缝背面保护对扫面焊焊缝成形及焊接过程稳定性的影响,进而为7075-T6高强铝合金填丝焊接技术研究提供了依据。在对送丝方式、送丝角度、送丝速度及焊丝与光束相对位置等参量优化的基础上,利用板条CO2激光器成功地实现了7075-T6高强铝合金的填丝对接焊缝。焊态下,采用AlSi12焊丝的接头强度为360.8 MPa;采用AlMg4.5MnZr焊丝的接头强度达到414.6 MPa。焊后经热处理,采用AlSi12焊丝的接头强度为404.2 MPa,达到母材的75％,采用AlMg4.5MnZr焊丝的接头强度达到482.6 MPa,为母材的88％。

Experimental study of slab CO2 laser bead-on-plate welding and filling wire welding 7075-T6 high strength aluminum alloy of 2.4 mm thickness has been completed. The mechanical properties of welding joints have been analysed. Through analysis of influence of laser power, focal length, welding velocity, working gas and shielding gas on weld shaping and welding stability, filling wire welding of 7075-T6 high strength aluminum alloy is put forward. On the basis of the optimization of feeding direction, feeding angle, feeding velocity and feeding position, filling wire welding of 7075-T6 alloy is completed successfully with slab CO2 laser. The tensile strength of as-welded welds with AlSi12 is 360.8 MPa and with AlMg4.5MnZr 414.6 MPa. The tensile strengths of welds after heat treatment are 404.2 MPa (75 percents of base-metal) and 482.6 MPa (88 percents of base-metal) for AlSi12 and AlMg4.5MnZr, respectively.