激光偏移量对Hastelloy C-276/316L焊缝腐蚀性能的影响

Effects of Laser Offset on the Corrosion Performance

摘要:

使用Nd:YAG连续激光对Hastelloy C-276/316L薄板进行异质焊接实验，分析不同激光偏移量下焊缝元素含量变化规律，借助极化曲线、电化学阻抗谱研究不同激光偏移量下焊缝在盐酸溶液中的抗蚀性能。结果表明：调节激光偏移量Fe、Ni和Mo含量变化明显，而Cr含量无明显变化；当激光向Hastelloy C-276偏移0.1~0.3 mm时，焊缝中主要元素含量变化较小，腐蚀电压、电荷转移电阻最大，腐蚀电流密度最小，焊缝腐蚀趋势、腐蚀速率最小，焊缝抗蚀性能较好；当激光向316L偏移0至0.2 mm时，焊缝中Fe元素逐渐增加，Ni、Mo元素含量逐渐下降，焊缝的腐蚀电压、电荷转移电阻递减，腐蚀电流密度递增，焊缝的腐蚀趋势、腐蚀速率逐渐增大，焊缝抗蚀性逐渐减弱

Abstract:

Dissimilar welding experiments of Hastelloy C-276/316L thin sheet was performed by Nd:YAG continuous laser. The element content changes of the weld under different laser offsets were studied and the effects of laser offset on the corrosion performance of Hastelloy C-276/316L weld in HCL solution were also investigated by means of polarization curves and electrochemical impedance spectroscopy. The results show that Ni, Fe and Mo contents change significantly with adjusting the laser offset, while Cr element content has no obvious change. When the laser offset is between 0.1~0.3 mm, the main element contents in the weld change slightly, the corrosion voltage and the charge transfer resistance are the largest and the corrosion current density is minimal. At this time the corrosion trend and the corrosion rate of the weld is minimum. Therefore, the corrosion resistance of the weld is the best under this parameter. When the laser offset changes from 0 to –0.2 mm, the content of Fe in the weld increases gradually, but the contents of Ni and Mo decrease. It is the main cause of the decrement of corrosion voltage and the charge transfer resistance. Corrosion current density increases and the corrosion trend as well as the corrosion rate of the weld increase gradually. As a result, the corrosion resistance of weld shows a trend of weakening under this parameter