Friction stir spot welding was successfully applied to the 1.4 mm thick galvanized DP590 dual-phase steel plates using a W-Re alloy rotating tool. During welding, a constant rotation speed of 800 rpm and a dwell time of 3 s were used and the tool penetration depth was ranged from 0 to 0.9 mm in order to study the flowing behavior and distribution of the Zn element in the joints. It was revealed that different forms of Zn were present along the interface. For example, there were Zn aggregates at the edge of the bonded interface, and there were droplet-like Zn particles along the partially bonded interface. Layers of accumulated Zn also existed outside the weld nugget. No obvious Zn element was detected inside the entire stir zone away from the interface. With the increase of penetration depth, the size of martensite in the stir zone increased from 8 to 14.2 μm. When the penetration depth was less than 0.6 mm, the shear tensile tests of the FSSW joints showed that the existence of Zn at the hook-like interfaces reduced the mechanical properties of the joints. However, when the penetration depth was larger than 0.6 mm, no noticeable effect of Zn was found for the joints with straight interfaces and a higher shear tensile load could be reached. The maximum shear tensile load was about 21.35 kN through the plug failure mode when a bonded interface of 1.9 mm was formed at a penetration depth of 0.8 mm.

使用W-Re合金旋转工具，将搅拌摩擦点焊成功地应用于1.4毫米厚的镀锌DP590双相钢板。在焊接过程中，使用800 rpm的恒定转速和3 s的停留时间，工具穿透深度为0到0.9 mm，以研究接头中Zn元素的流动行为和分布。揭示了沿界面存在不同形式的Zn。例如，在键合界面的边缘存在Zn聚集体，并且在部分键合界面处存在液滴状的Zn颗粒。焊点外还存在累积的锌层。在远离界面的整个搅拌区内，均未检测到明显的锌元素。随着穿透深度的增加，搅拌区的马氏体尺寸从8微米增加到14.2微米。当穿透深度小于0.6 mm时，FSSW接头的剪切拉伸试验表明，钩状界面处Zn的存在降低了接头的机械性能。但是，当穿透深度大于0.6 mm时，对于具有直界面的接头，没有发现Zn的明显影响，并且可以达到更高的剪切拉伸载荷。当插入深度为0.8 mm时形成1.9 mm的粘结界面时，在插塞破坏模式下，最大剪切拉伸载荷约为21.35 kN。当穿透深度大于0.6 mm时，对于具有直界面的接头，未发现Zn的明显影响，并且可以获得更高的剪切拉伸载荷。当插入深度为0.8 mm时形成1.9 mm的粘结界面时，在插塞破坏模式下，最大剪切拉伸载荷约为21.35 kN。当穿透深度大于0.6 mm时，对于具有直界面的接头，未发现Zn的明显影响，并且可以获得更高的剪切拉伸载荷。当插入深度为0.8 mm时形成1.9 mm的粘结界面时，在插塞破坏模式下，最大剪切拉伸载荷约为21.35 kN。