铝合金5A02不等厚板的CO2激光填粉拼焊

在填加粉末的条件下,采用CO2激光器焊接铝合金5A02不等厚板,研究焊接参数对焊缝成形的影响;利用金相显微镜、扫描电镜、拉伸试验机分别研究了激光拼焊板焊接接头的力学性能、断口形貌及微观组织特点.结果表明,填加粉末可使5A02不等厚薄板的激光焊接过程的稳定性显著提高,在比较宽的参数范围内,可以得到成形良好的焊缝;拼焊板的横向拉伸试样均断裂于薄板热影响区,拉伸性能与母材中变形能力较好的板料所占比例有关,该比例越大则拼焊板具有较大的延伸率,变形能力越强;拼焊板的焊缝组织极为细小,在熔合线附近开始向焊缝中心生长的是树枝状晶,在焊缝中心是等轴晶.

CO2 laser welding of tailored 5A02 aluminum alloy sheets with different thickness using filler powder

CO₂ laser was used to weld 5A02 aluminum alloys sheet with different thickness with filler metal powder and without powder.The influences of the filler metal powder on the weld appearance and process stability was studied.Using tensile tests, microscope and SEM, the mechanical and microstructure characteristics of the welded joints were evaluated, and the effect of the weld distribution on the plastic formability of the TWB(tailored welded blanks) were analyzed.The results indicate that the addition of the metal powder can enhance the energy coupling efficiency during laserwelding of 5A02 aluminum alloys sheet with different thickness, and the weld appearance and process stability can be improved greatly.In a wide range of parameters for this alloy sheet with different thickness, the weld appearance is very well.The total elongation in the longitudinal direction for the laser welds decreased greatly.The specimens of the TWB in the transverse direction all fractured on the HAZ of the thinner base metal, the main reason is the thinner base metal of half-harded state was annealed during welding.The ductibility of the TWB is effected by percent of the sheet in a TWB.The total elongation increases with the percent of the sheet with better ductibility. The microstructure of the welds from the fusion line to the weld is cellular dendrite structure, and it is the finer equl-axed grains in the center of fusion zone.