非穿透激光深熔焊熔深与等离子体光信号的关系

对于非穿透激光深熔焊而言 ,焊接熔深是最重要的质量参数之一 ,对其进行实时监测具有重要意义。通过采集和分析激光焊接过程中等离子体光信号以探索焊接熔深的实时监测技术。研究结果表明 ,当激光功率不变时降低焊接速度 ,或焊接速度不变时提高激光功率 ,在焊缝熔深加大的同时 ,采集到的等离子体光信号强度亦呈明显上升趋势 ;在工艺参数不变的同一焊缝内 ,对应焊缝光信号的频谱图中存在明显主频 ,且随着焊接线能量的提高 ,主频率下降 ;同一焊缝内由于某些不稳定因素导致局部焊缝熔深变化超过 8%时 ,等离子光强明显下降 ,而对应该段信号的幅值谱不存在明显主频率。

Relationship Between Penetration Depth and Plasma Optic Signal During Partial-Penetration Laser Welding

The penetration depth is one of the most important quality parameters in partial penetration laser welding,and therefore real time monitoring for penetration depth becomes extremely significants.A system was built for real time monitoring the penetration depth of laser welding by measuring and analyzing the plasma optical signal induced by laser.The experiments and analyses show that if increasing the laser power or reducing the speed,the penetration depth is increased and the plasma optical intensity is also increased.A characteristic frequency component exists in the signal from the amplitude spectrum analysis for a whole weld seam which is welded under the same welding parameters,what's more,the characteristic frequency falls as the welding heat input increases.When an 8% fluctuation in the penetration depth is caused by random unstable factors in the same weld seam,the optical signal amplitude decreases rapidly,and there is no characteristic spectrum line in the corresponding signal amplitude spectrum.