应用激光, 2015, 35 (2): 196, 网络出版: 2015-05-20
低碳钢与奥氏体钢激光焊接接头的组织与性能
Microstructure and Properties of Laser Welded Joints between Low Carbon Steel and Austenitic Steels
异种材料 激光焊接 低碳钢 奥氏体钢 显微组织 dissimilar materials laser weld low carbon steel austenitic steel microstructure
摘要
异种材料焊接是使零部件具有多功能的有效途径, 但材料性能差异导致焊接接头效果不佳。采用300 W的Nd∶YAG脉冲激光器, 对低碳钢和奥氏体钢进行激光焊接, 研究了激光焊接接头的微观组织、显微硬度及拉伸性能的变化规律, 探讨了微观组织与力学性能之间的本质关系。结果表明, 低碳钢的微观组织是铁素体+马氏体, 奥氏体钢的微观组织是具有孪晶结构的奥氏体。低碳钢-低碳钢焊接接头焊缝区显微组织是板条马氏体, 热影响区组织是马氏体+铁素体, 焊缝区硬度是母材的1.85倍, 拉伸断裂位置位于母材; 奥氏体钢-奥氏体钢焊接接头焊缝区的显微组织是等轴状和柱状奥氏体, 无明显的热影响区, 焊缝区硬度与母材持平, 拉伸断裂位置位于焊缝, 焊接过程中孪晶的消失使奥氏体钢塑性明显降低; 低碳钢-奥氏体钢的焊接接头焊缝区显微组织与奥氏体钢自身焊接组织一致, 仅在低碳钢一侧存在明显热影响区, 焊缝硬度高于奥氏体钢母材而与低碳钢母材持平, 拉伸断裂位置位于奥氏体钢母材; 三种焊接接头拉伸断裂方式均为韧性断裂。
Abstract
Welding of dissimilar materials is an effective way to make part with multi-functional, but different properties between dissimilar materials lead to poor properties of welded joints. In this paper, a 300 W Nd∶YAG pulsed lasers was selected to laser weld the low carbon steel and Austenitic steel. Then the change of microstructure、mechanical properties and the fracture type of laser welded joints were analyzed and the relationship between microstructure and mechanical properties was discussed. The results showed that the microstructure of low carbon steel as ferrite and martensite and the microstructure of Austenitic steel was austenitic which had many twins. The microstructure in welded seam of low carbon-low carbon steel was lath martensite and the microstructure was mostly martensite +little ferrite in the HAZ, the hardness of welded seam was 1.85 times higher than that in the base metal, the welded samples failed at base metal; The microstructure in welded seam of austenitic-austenitic steel was equiaxed grains and columnar grains, HAZ was not found in the joint, Hardness between welded seam and base metal was mostly similar, the welded samples failed at welded seam, the plasticity of austenitic steel significantly reduced when the twins was disappearance in the welding process. The microstructure in welded seam of low carbon-austenitic steel was similar with the microstructure of austenitic-austenitic steel, HAZ only existed in low carbon steel. Hardness of the welded seam was higher than the base metal of austenitic steel but equal to the base metal of Low carbon steel. The welded samples failed at welded seam. The fracture mode of three joints was ductile fracture.
杨兆华, 陈长军, 王晓南, 张敏, 朱广江. 低碳钢与奥氏体钢激光焊接接头的组织与性能[J]. 应用激光, 2015, 35(2): 196. Yang Zhaohua, Chen Changjun, Wang Xiaonan, Zhang Min, Zhu guangjiang. Microstructure and Properties of Laser Welded Joints between Low Carbon Steel and Austenitic Steels[J]. APPLIED LASER, 2015, 35(2): 196.