1Cr18Ni9Ti不锈钢摆动激光焊接接头成形性能研究

    Forming Performance of 1Cr18Ni9Ti Stainless Steel Laser Oscillating Welding Joints

    • 摘要: 采用不同摆动频率和摆动幅度开展1Cr18Ni9Ti不锈钢的摆动激光焊接试验,研究了不同摆动激光工艺参数对焊缝气孔率和宏观形貌,接头微观组织和力学性能的影响规律。结果表明:与摆动频率相比,增加摆动幅度可有效降低焊缝气孔率,在100 Hz频率、1.5 mm幅度时,气孔率降至0.19%。随着摆动频率的增加,钉头宽度先下降后变化不大,随着摆动幅度的增加,钉杆宽度逐渐增加而熔深减小。不同摆动频率和幅度下焊缝微观组织差别不大,主要由骨架状和板条状铁素体以及奥氏体组成。上部焊缝边缘比焊缝中心有更多的板条状铁素体,而下部焊缝过渡区比上部焊缝边缘有更为细小的组织形态。焊缝与母材的整体硬度差异不大,且不同摆动参数下焊缝平均硬度也未发现明显变化。接头拉伸主要断裂在母材位置,其断口的宏观颈缩现象和微观韧窝特征均表明拉伸过程中主要发生了塑性断裂。

       

      Abstract: Laser oscillating welding tests of 1Cr18Ni9Ti stainless steel were carried out by using different oscillating frequencies and oscillating amplitudes, and the effects of different oscillating laser process parameters on the porosity and macroscopic morphologies of the welds, the microstructure and mechanical properties of the joints were studied. The results show that compared with the oscillating frequency, increasing the oscillating amplitude effectively reduces the porosity of the weld. The porosity decreases to 0.19% under 100 Hz frequency and 1.5 mm amplitude. With the increase of the oscillating frequency, the width of nail head decreases firstly and then changes little. With the increase of the oscillating amplitude, the width of nail rod gradually increases, while the weld penetration decreases. There are little differences in the microstructures of the welds under different oscillating frequencies and amplitudes, which are mainly composed of skeletal and strip ferrite and austenite.The upper weld edge has more strip ferrite than the weld center, while the lower weld transition zone has finer microstructure than the upper weld edge. The hardness of the weld and base metal has little differences, and the average hardness of the welds has no obvious changes under different oscillating parameters. The tensile fractures of the joints are mainly at the base metal, and the macroscopic necking phenomenons and microscopic dimple characteristics of the fractures indicate that plastic fracture mainly occurs during tensile process.

       

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