激光拼焊焊缝显微组织及精细结构分析

Microstructure of Weld Seam by Laser Tailor Welding and Analysis on Its Fine Struture

将厚度为1.2 mm和0.8 mm的低碳冷轧汽车薄板通过激光拼焊工艺焊接成一个整体,利用光学金相显微镜和透射电子显微镜研究了焊缝处的显微组织和精细结构,并利用显微硬度计连续地测量了焊缝处的显微硬值。结果表明,该钢激光拼焊缝焊处组织为通过块型转变形成的块型铁素体,其位错密度高于多边形铁素体,块型铁素体硬度介于先共析铁素体与贝氏体之间。

The low carbon cold rolled steel sheets with thickness of 0.8 mm and 1.2 mm for automobile are welded into tailor welded blanks by laser tailor welding technology.The microstructures and fine structures at the weld seams of these blanks are studied by the optical microscope and transmission electron microscope.And also the values of the micro-hardness on these weld seams are measured continuously by the micro-hardness meter.The results show that microstructures at the seams are massive ferrites formed by massive transformation whose dislocation densities are much more than that of polygonal ferrites and their values of micro-hardness are between the values of eutectoid ferrites and bainites.