硅对304不锈钢GMAW高速焊接头组织性能的影响

以不锈钢焊丝中Si元素含量不同对高速焊焊后焊缝成形以及接头组织性能为研究目的，采用GMAW焊接工艺方法，借助扫描电镜、XRD衍射图谱、拉伸以及微观硬度等力学性能测试作为分析手段，深入研究Si元素在焊缝内部空间分布规律，及其对焊后成形焊缝组织和力学性能的影响规律. 结果表明，焊丝中存在特定含量的Si元素，不仅能够增加熔池金属流动性，提高焊接过程稳定性，改善焊后焊缝成形；同时焊接速度可以大幅提高至120 cm/min；由于Si元素的存在，GMAW高速焊焊后接头组织主要为奥氏体+δ铁素体，焊缝组织得到优化. XRD衍射图谱中发现焊后接头组织中存在马氏体和渗碳体，焊后接头微观硬度有所增加，拉伸性能基本持平，且在拉伸断裂前有明显的颈缩，塑性及抗拉强度良好.

Effect of silicon on microstructure and properties of high speed GMAW welded joint of 304 stainless steel

By stainless steel welding wire with different Si element content, the weld forming, microstructure and performance after high-speed welding has been organized for research purposes, with the GMAW welding method,by analysis means of SEM, XRD diffraction pattern, mechanical properties such as stretching and the micro hardness testing, to further study of Si elements in the weld internal space distribution, and its influnce rule on microstructure,mechanical properties when forming after welding. The results show that the specific content of Si element in the welding wire can not only increase the metal fluidity in the weld pool, but also improve the stability of the welding process and the weld forming after welding. At the same time, the welding speed can be greatly increased to 120 cm/min; As a result of the existence of element Si, the joint organization after GMAW high-speed welding mainly austenite and δferrite, weld organization optimized.In XRD diffraction pattern after welding, martensite and cementite exists in the joint organization, micro hardness increased, tensile properties are basic flat, and apparent necking have appeared in front of the tensile fracture, plasticity and tensile strength are good.