不锈钢激光-MAG复合焊接头成型规律及性能

Forming Rules and Performances of Laser-MAG Hybrid Welding Joints of SUS301L-MT Stainless Steel

为了给新一代城轨列车的焊接制造提供技术支持,以列车用6 mm SUS301L-MT奥氏体不锈钢为研究对象,采用焊缝截面分析、金相观察、X射线衍射法、残余应力测试等手段,研究了激光-MAG(metal active gas welding)复合焊接头的成型规律及接头性能.结果表明:激光功率、离焦量增大能增加焊缝上表面熔宽;焊接速度增加后,焊缝中部熔宽和下表面熔宽明显减小;焊缝宽度比随离焦量的增大显著增加;焊缝组织为奥氏体+δ铁素体;接头纵向残余应力在接头中心位置存在极大值,约为330 MPa.

This study focusses on 6 mm-thick SUS301L-MT austenitic stainless steel,which will be used for the manufacture of next-generation city rail trains. In order to establish the technical foundation for the manufacture of city rail trains, the forming rules and performances of 6 mm-thick SUS301L-MT austenitic stainless steel laser-MAG （ metal active gas welding） hybrid welding T-joints were studied using weld cross-section analysis,metallographic observation,X-ray diffraction residual stress tests, etc. The increase of laser power and defocusing distance can improve the width of the weld top surface. When welding speed increases, the widths of the weld middle section and weld bottom surface significantly decrease. The width of the weld cross-section increases significantly with the increase in defocusing distance. The microstructure of the weld zone is austenite mixed with ferrite. The maximum longitudinal residual stress appears at the center of the joint, with a value of 330 MPa.