Friction Stir Welding (FSW) is a candidate to overcome problems traditionally encountered when conventional fusion welding methods are applied to join low weldability metals. Moreover, FSW shows greater performance than conventional fusion welding in joining materials with dissimilar welding characteristics. However, since FSW is still a relatively new technique, more research is needed to improve the methodology and achieve a better understanding of the physical phenomena that occur during the FSW process. The focus of this paper is the role that the pin’s shape plays on the achievable tensile strength. To this aim, three pin’s shapes are considered, namely circular (baseline), square, and triangular. The effects of the pin’s shape is studied by mean of experiment and numerical methods. The effect of pin geometry on double side stir welding (DSFSW) is also experimentally studied. It is proven that a modified pin geometry can indeed improve the tensile strength of FSW joints obtained with a cylindrical pin. DSFSW significantly improves the joint quality since it provides strain hardening in the interference zone and better mixing when the second pass is applied.

搅拌摩擦焊（FSW）是克服传统熔焊方法用于焊接低可焊性金属时传统上遇到的问题的候选方法。此外，FSW在具有不同焊接特性的接合材料中表现出比常规熔焊更高的性能。但是，由于FSW仍然是一种相对较新的技术，因此需要进行更多的研究来改进方法并更好地理解FSW过程中发生的物理现象。本文的重点是销钉形状对可达到的拉伸强度的作用。为此，考虑了三种销钉的形状，即圆形（基线），正方形和三角形。通过实验和数值方法研究了销钉形状的影响。还通过实验研究了销钉几何形状对双面搅拌焊（DSFSW）的影响。事实证明，修改后的销钉几何形状确实可以改善用圆柱销钉获得的FSW接头的抗拉强度。DSFSW显着改善了接头质量，因为它在干涉区域提供了应变硬化，并在第二遍应用时提供了更好的混合。