An Investigation of different parameters on the penetration depth and welding width of Ti-6Al-4V alloy by plasma arc welding

In this investigation, the effect of plasma arc welding (PAW) process parameters on the welding quality of Ti-6Al-4V alloys is studied. These parameters including current, welding linear velocity and plasma gas composition that affected on the weld bead width. Macrograph results indicated that there is a certain range of electric current and linear velocity, which within the range, the full penetration welding obtains, and the weld bead is free from defect. As a result, the mechanical properties are favorable and comparable to those of the base material. It can be protected weld bead from oxidation with argon gas (5N). Furthermore, the automation of the process resulted in repeatability of the plasma arc welding is very good and the weld quality is well controlled. The results indicated that increasing the amount of helium gas, increases the welding area and the higher penetration depth of the weld. Examination of the microstructure of the weld region shows that there are three serrated alpha phase, alpha-beta phase (Widmanstätten) and the martensitic phase in the weld microstructure.