本试验采用IPG YLS-5000型激光焊接系统，焊接舰船用高强钢907A三明治板。采用万能试验机、显微硬度仪、超景深三维数码显微镜以及扫描电镜，测定了T型焊接接头的拉脱力学性能、显微硬度、显微组织和断口形貌。结果表明，焊缝和热影响区的显微硬度均高于母材，焊缝显微硬度在330~360 HV0.2之间；焊缝组织为板条马氏体，热影响区组织主要为马氏体、残余奥氏体及少量析出碳化物；T型接头断口属于兼有韧性断裂和解理断裂的综合断裂；焊接速度和离焦量一定时，焊缝宽度和深度随激光功率的提高而增大；T型搭接接头的力学性能主要取决于搭接处的焊缝宽度，在当前工艺条件下进行3道次的激光焊，能保证腹板和面板的接合强度比母材的强度大。

Laser welding high strength steel 907A sandwich structure by IPG YLS-5000 laser welding system in this experiment. Tensile properties, microstructure, fracture morphology and microhardness of T-joints are measured by universal testing machine, microhardness tester, super depth of field three-dimensional digital microscope and scanning electron microscope. The results show that, the microhardnesses of welding seams and heat affected zone are higher than that of base metal. The microhardness of weld seam is between 330 HV0.2 and 360 HV0.2. Microstructures of weld seams are lathy martensites, and microstructures of heat affected zone mostly are martensites, residual austenite and a small amount of carbides. T-joint fracture is a composite fracture, which both have ductile fracture and cleavage fracture. In the case that welding speed and coke are certain, weld width and depth increase with higher laser power. Mechanical performance of T-joint mainly depends on the weld width. Under the conditions of this test process, it needs 3 times single laser welding, to ensure that the web and panel joint strength is bigger than the strength of the base metal.