Deposition Test Of Inconel718 Welding Materials And The Study Of Microstructure And Properties

As for important structural materials, some problems in welding were encountered for Inconel 718 alloy during application. Other difficulties are encountered in the welding of Inconel 718 in the bead and heat-affected zone, such as hot cracking and post-weld age cracking. The plasticity and ductility of Inconel 718 weldments are somewhat inferior to those of the base metal. It is important to study the special welding material of Inconel 718 alloy for base metal.By adjusted chemical composition of Inconel 718 alloy,five different chemical composition wires were obtained.We obtained deposition coating by deposition test. By microstructure observing, and mechanical properties testing, we studied the influence of wire chemical composition and heat treatment on the microstructure and mechanical properties of the Inconel 718 alloy deposit coating.The results showed that the optimum chemical composition wires for Inconel 718 alloy is 0.026% C,17.92% Cr,5.6% Nb,1.19% Ti,3.0% Mo,0.47% Al,18.99% Fe and 52.8% Ni. The microstructure of the deposit coating was composed of y solid solution, the y solid solution is made up of dendritic crystal. The crystal grain is more coarse after diffusion annealing heat treatment at 1190 ℃ for 12h followed by solution treatment at 1030℃ for 30min,but the crystal grain doesn't channge after aging treatment at 720 ℃ for 10h. Laves phases formed during welding and was dissolved completely after diffusion annealing treatment at 1190 ℃ for 12h.The main carbide is (Nb, Ti)C and distributes on the base. The pattern and quantities of carbide don't channge after diffusion annealing, solution and aging treatment. The optimum chemical composition deposition metal obtained the best over-all properties after diffusion annealing treatment at 1190 ℃ for 12h followed by solution treatment at 1030℃ for 30min and aging treatment at 720 ℃ for 10h,but obtained the good yield and tensile strength after diffusion annealing treatment at 1190℃ for 12h followed double aging treatment at 720℃ for 8h and 620℃ for 8h.