Joining of Ti-۶AL-۴V to AISI ۳۰۴ Stainless Steel using Laser Spot Welding with Circular Technique

In this research, dissimilar laser spot welding of the Ti-۶Al-۴V and AISI ۳۰۴ (stainless steel) was investigated. The joining of ۰.۷ and ۰.۵ mm thickness plates with using a copper interlayer of ۰.۲ and ۰.۳ mm in thickness was performed by LSW. A ۴۰۰-W Nd: YAG laser pulse welding machine was used to obtain coaxial spot welds of ۴ mm in diameter with circular technique. Visual inspection and metallographic examination were used for all samples. If no crack was identified, micro-Vickers hardness test, tensile test, and scanning electron microscopy (SEM) were performed on the samples. The result indicated that with a copper interlayer and ۱۰.۷ J heat input on peak power of ۱.۵ kW, welding frequency ۱۵ Hz, and welding time of ۷ ms, leading to an ultimate strength of ۱۶۰ MPa.  In addition the result indicated that applying the circular technique by creating adjacent spot welds can produce a good joint.