激光焊接5083/6016异种铝合金光谱信号与焊件质量的关系

采用光纤激光器对1.0mm厚5083和1.2mm厚6016异种铝合金平板试件进行激光搭接焊试验,利用光谱测量系统、扫描电镜、维氏显微硬度仪和微机控制的电子万能试验机等手段,检测激光焊接过程等离子体产生时辐射出的时域MgI光谱信号,分析焊缝形貌、显微硬度和力学性能,研究等离子体中MgI光谱信号相对强度与焊件质量之间关系.结果表明,随着扫描速度增加,MgI光谱信号强度降低,离焦量对MgI光谱信号作用明显,而激光功率对MgI信号整体幅度改变较小;MgI光谱强度较小或较大,试件出现焊不透或焊穿现象;MgI等离子体信号波动较大处,出现咬边、凹陷、气孔等缺陷,力学性能低;而MgI等离子体信号平稳时,焊缝平整,缺陷少,力学性能好.基于MgI光谱信号与焊件质量之间的对应关系,运用Hugh hart的统计过程控制(SPC)理论,建立了焊接过程单值-移动极差控制(X-Rs)图.

Relation between Spectrum Signal of 5083/6016 Dissimilar Alloy Laser Welding and Weldment Quality

The laser welding test was carried out on the 5083 aluminum alloy with thickness 1.0 mm and the 6016 aluminum alloy with thickness 1.2 mm. The relationship between plasma MgI spectrum signal and the process parameters as well as welding quality were studied by testing the MgI singal of laser welded dissimilar alloy and by analyzing fracture morphology,microhardness and mechanical properties in the joint by using spectroscopic measurement system, scanning electron microscope, vickers microhardness machine, and computer control electronic universal testing machine. The results show that, with the speed increasing, MgI spectrum signal strength is reduced; the focus obviously affects MgI signal while the laser power changs the whole MgI signal amplitude slightly. When MgI relative strength appears smaller or larger, the specimens have lack or over welding; MgI plasma with strong fluctuations leads to defects such as porosity and low mechanical performance while smooth MgI signal has less defect and good mechanical performance. The real-time control welding process X -Rs is established based on MgI spectral signal corresponding to the quality of weldment and Hugh hart SPC control theory.