不同填充材料下316LN/Inconel 718异种激光焊接头的显微组织与力学性能

目的研究不同填充材料下316LN/Inconel 718异种激光焊接接头的显微组织、显微硬度及室温拉伸性能。方法分别对316LN/Inconel 718异种材料在不填充焊丝、填充ER316LMn焊丝和填充HGH4169焊丝的情况下进行激光对接试验。采用XJP-2C型倒置光学显微镜观察不同填充材料下接头的显微组织,401MVD型数显显微硬度计测量不同填充材料下接头显微硬度,WDW-100型万能电子试验机测量不同填充材料下接头的室温拉伸抗拉强度,最终,对不同填充材料下316LN/Inconel718激光焊接接头的显微组织和力学性能进行对比分析。结果不填充焊丝与填充ER316LMn焊丝时,可获得外观成形良好的焊接接头;填充HGH4169焊丝时,接头外观成形稍差,但力学性能较好;不填充焊丝时,焊缝组织主要为柱状树枝晶、胞状晶和等轴树枝晶,填充焊丝时,焊缝组织主要为柱状树枝晶和胞状晶。填充焊丝和不填充焊丝情况下,316LN侧熔合区均会产生分层现象,而Inconel 718侧熔合区分层现象则不明显;当填充HGH4169焊丝时,焊缝的显微硬度值与抗拉强度值最大,焊缝填充ER316LMn焊丝时次之,不填充焊丝时最小。接头抗拉强度最大值为764.59 MPa,接头断裂方式为典型的韧性断裂。结论填充焊丝较不填充焊丝时,接头的力学性能有所提高,且填充HGH4169焊丝时,接头的力学性能达到最佳,但焊缝的宏观成形难以控制。

Microstructure and Mechanical Properties of 316LN/Inconel 718 Dissimilar Alloy Laser Welding Joint with Different Filling Materials

The paper aims to study microstructure, microhardness and room temperature tensile properties of Inconel 718/316LN dissimilar laser welded joints with different filling materials. Docking tests were performed on Inconel 718/316LN dissimilar materials with different filler wire: ER316LMn filler wire and HGH4169 filler wire. The microstructure of the welded joint was observed with XJP-2C inverted optical microscope. The microhardness of the joint was measured with 401MVD digital microhardness tester. The tensile test was performed on the tensile specimen with WDW-100 universal electronic tester. The microstructure and mechanical properties of 316LN/Inconel 718 laser welded joints with different filling materials were compared and analyzed. The results show that when the no filler wire and the ER316LMn welding wire is filled, the welded joint with good appearance can be obtained. When the HGH4169 welding wire was filled, the joint appearance was poor slightly, but the mechanical property was better. When the welding wire was not filled, the weld bead was mainly composed of columnar dendrites, cell crystals and equiaxed dendrites. When the wire was filled, the weld bead structure was mainly columnar dendrites and cell crystals. Whether the filler wire was filled or not, stratified phenomenon both appeared at the fusion zone of 316LN side will, while the fusion zone of Inconel 718 side was not obvious. When the HGH4169 wire was filled, the microhardness and tensile strength of the weld were the largest, followed by weld filled with ER316LMn wire. It was the minimum when the wire was not filled. The maximum value of the tensile strength of the weld joint was 764.59 MPa, and the fracture mode of the joint was a typical ductile fracture. When the weld is filled with wire, the mechanical properties of the joint are improved. When the HGH4169 wire is filled, the mechanical properties of the joint are optimal, but the macroscopic formation of the weld is difficult to be controlled.