激光焊接焊缝显微组织磁光成像研究

Research on magneto-optical imaging of laser welded seam microstructure

针对焊缝显微组织对焊件质量影响问题,对激光焊接焊件不同区域的焊缝显微组织特征进行研究,对不同焊接试验参数下的焊缝成形差异进行分析,提出了一种焊缝显微组织磁光成像检测方法,采用低碳钢平板对接焊,试验共分为4组,将焊缝显微组织磁光图像与扫描电镜图像相结合,分析恒定磁场下不同区域焊接接头的显微组织磁光成像差异和焊缝的晶粒组成及特征。研究结果表明,在磁光图像中焊件焊缝可以分为熔合区、热影响区和母材区,且这3个区域的晶粒组成、大小及形态有明显的差异,恒定磁场下焊缝磁光图的颜色、亮度及灰度值反映了焊缝的成形质量。

Aiming at the importance of microstructure on the properties of the weldment,the characteristic of the microstructure of laser welded joint in different regions were studied.The differences of weld forming under different laser welding parameters were analyzed,and a magneto-optical imaging method for researching weld microstructure was proposed.The color,brightness and gray value of magneto-optical image of the weld show the qualities of the weld forming under the constant magnetic field.Laser welding test consists of four groups with butt welding of low carbon steel.The magneto-optical images of the weld microstructure and the scanning electron microscope images were combined to analyze the difference of the microstructures,the grain compositions and characteristics of the weld joints in different regions.The experimental results show that the weld joint can be divided into the fusion zone,the heat affected zone and the base metal zone in magneto-optical images,and the grain's compositions,sizes and shapes in the three regions are obviously different.