大截面钢/铝摩擦焊接头力学性能及显微组织分析

Analysis on Mechanical Properties and Microstructure of Friction Welded Joints for Large Cross-section Steel/Aluminum

针对大截面铸态纯铝与Q235钢异种金属,采用连续驱动摩擦焊技术进行焊接试验,通过光学显微镜观察、电子探针分析、常温和高温拉伸性能及硬度测试,探讨了其焊接接头的微观组织和力学性能。研究表明,大截面铸态纯铝与Q235钢间具有良好的摩擦焊接性,焊接接头强度等于或高于铝基材;高温条件下,试样均断于铝端母材,抗拉强度随着温度的升高呈现出明显的下降趋势,而伸长率随温度升高而增大;焊接接头在近缝区发生了晶粒细化,在粘塑性层内发生了一定程度的原子扩散,形成扩散层。

For large cross-section cast aluminum and Q235 steel dissimilar metals, continuous drive friction welding technology was used for welding test. By means of optical microscopy observation, electron microprobe analysis, and the test of hardness and tensile properties at high temperature and room temperature respectively, the microstructure and mechanical properties of dissimilar welded joints between Q235 steel and aluminum were discussed. The research indicates that there are good friction welding properties between the large cross-section cast aluminum and Q235 steel, and the strength of welded joint is equal to or higher than that of aluminum substrate. Under the high-temperature conditions, all the samples fracture in the side of aluminum; with the rise of temperature, tensile strength of the joint declines obviously, while elongation increases; the grain refinement occurs near the welded joint, and a certain degree of atomic diffusion takes place in the visco-plastic layer, forming the diffusion layer.