Optimization of Nd:YAG-laser welding process for Inconel 718 alloy

Ni-based superalloys are extensively used in the manufacture of aircraft engine components because of their excellent heat-resistant and corrosion-resistant properties. The principal joining processes for Ni-based superalloys are TIG welding, MIG welding, submerged arc welding, electron beam welding, and CO2 laser welding. In this investigation, a robotic 4-kW continuous-wave Nd:YAG laser system was used to identify the optimal laser welding process for 2.0 mm thick Inconel (IN) 718 sheets. The effect of various processing parameters, which included power input, welding speed, weld geometry and filler wire, was studied using the Taguchi design of experiment (DOE) methodology. The DOE methodology enabled the evaluation of the relationship between the process parameters and the quality of the welded joints, from which the optimal Nd:YAG laser welding process was developed for IN718 alloy. Joint quality was examined by tensile and nondestructive testing methods. Using the optimal process established in this research, mechanically-sound welds with narrow fusion and heat-affected zones were produced. The outcome of this research demonstrates the feasibility of the application of Nd:YAG laser in the joining of IN718 sheets for the manufacture of aircraft engine components.Peer reviewed: YesNRC publication: Ye