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对30 mm厚的TC4钛合金板材进行窄间隙TIG单层填丝焊试验,研究了焊接电流对焊缝成形的影响,分析了焊接接头的显微组织和显微硬度。试验结果表明:随着焊接电流的增加,焊缝熔深、熔宽增加,焊缝表面下凹程度增大,但是焊缝熔宽增加幅度较小;焊缝区晶粒发生严重粗化,主要为粗大的柱状晶,其显微组织均为针状马氏体α’组织;靠近焊缝区侧的热影响区晶粒比靠近母材侧的粗化程度大。焊接接头显微硬度分布相似,焊缝区硬度稍高于母材硬度,并未存在明显的软化区;峰值硬度出现在热影响区,随着焊接电流增加,热影响区峰值硬度降低。
The narrow gap TIG single layer filler wire welding test was carried out on a 30 mm thick TC4 titanium alloy plate. The influence of welding current on the weld formation was studied. The microstructure and microhardness of the welded joint were analyzed. The experimental results show that with the increase of welding current, the weld penetration depth and weld width increase, the weld surface concavity degree increases, but the weld weld melt width increases less; weld grain coarsely roughened, the main Is a coarse columnar crystal, the microstructure of which is acicular martensite α ’; the heat affected zone close to the weld zone has a greater degree of coarsening of the grains than the base material side. The microhardness distribution of the welded joint is similar, the hardness of the weld zone is slightly higher than the hardness of the base metal, and no obvious softening zone exists. The peak hardness appears in the heat affected zone. As the welding current increases, the peak hardness of the HAZ decreases.