Luo Haitao, Wu Tingke, Fu Jia, Wang Wei, Chen Ning, Wang Haonan
Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China.
Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China.
Materials (Basel). 2019 Feb 4;12(3):480. doi: 10.3390/ma12030480.
According to the actual size parameters, the finite element model (FEM) of friction stir welding (FSW) was established, and the FEM was updated by experiments. The FSW of the 2A14-T6 high-strength aluminum alloy was simulated under a reasonable welding process parameter range, and the welding process parameters with good simulation effect were determined. The test was carried out under the same parameters, and the axial force of the FSW tool and temperature of the workpiece measuring point were collected. The comparison between the simulated data and the experimental data is reasonable, indicating the correctness of the FEM. The microstructure analysis of the welded joint shows that the grain size in the upper part of the weld nugget was smaller than that in the middle and lower parts, and there are obvious boundaries of grain size in each region of the joint. The hardness of the joint in the upper layer is higher than that in the middle and lower layers, and the minimum Vickers hardness value of the joint appears near the interface between the thermo-mechanically affected zone and the heat-affected zone on both sides of the weld. Tensile testing shows that the strength coefficient of the joint reaches 82.5% under this process parameter, and the sample breaks at the intersection of the material flow during stretching. After analyzing the final mechanical properties of the joint, we found that a degree of aerospace application can be achieved. Under this parameter, the welding test was carried out on the top cover of the rocket fuel tank. Firstly, melon valve welding, which is relatively difficult in welding conditions, was carried out, and a high-quality joint with good surface and no defects was obtained.
根据实际尺寸参数建立了搅拌摩擦焊（FSW）的有限元模型（FEM），并通过实验对有限元模型进行了更新。在合理的焊接工艺参数范围内对2A14-T6高强度铝合金的搅拌摩擦焊进行了模拟，确定了模拟效果良好的焊接工艺参数。在相同参数下进行试验，采集了搅拌摩擦焊工具的轴向力和工件测量点的温度。模拟数据与实验数据的比较合理，表明有限元模型的正确性。焊接接头的微观结构分析表明，焊核上部的晶粒尺寸小于中部和下部，接头各区域存在明显的晶粒尺寸边界。接头上层的硬度高于中层和下层，接头的最小维氏硬度值出现在焊缝两侧热机械影响区与热影响区的界面附近。拉伸试验表明，在此工艺参数下接头的强度系数达到82.5%，拉伸过程中试样在材料流动的交叉点处断裂。通过对接头最终力学性能的分析，发现该接头在一定程度上可实现航空航天应用。在此参数下，对火箭燃料箱顶盖进行了焊接试验。首先进行了焊接条件相对困难的瓜瓣阀焊接，获得了表面质量良好且无缺陷的高质量接头。
