Inconel 718 is a precipitation hardening nickel-chromium-iron alloy containing niobium and molybdenum. It has high strength, good toughness and corrosion resistance in high and low temperature environment at 700 ~C. The state of supply may be solid solution treatment or precipitation hardening.
Because of its high temperature strength, excellent corrosion resistance and workability at 700 C, it can be widely used in various high-demand occasions.
Inconel 718 Alloy is easy to process in various industrial processes.
Inconel 718 preheating
The workpiece must be cleaned before and during heating to keep the surface clean. Inconel 718 Alloy will become brittle if the heating environment contains sulphur, phosphorus, lead or other low melting point metals. Impurities come from marking paint, chalk, lubricating oil, water, fuel, etc. The sulfur content of fuel should be low, such as the impurity content of liquefied gas and natural gas should be less than 0.1%, the sulfur content of urban gas should be less than 0.25g/m3, and the sulfur content of petroleum gas should be less than 0.5%.
The heated electric furnace should have more precise temperature control ability, the furnace gas must be neutral or weak alkaline, and the fluctuation of the composition of the furnace gas in oxidation and reduction should be avoided.
Inconel 718 Hot Processing
Inconel 718 Alloy is suitable for hot working at 1120-900 C. The cooling mode can be water quenching or other rapid cooling mode. After hot working, it should be annealed in time to ensure the best performance. The material should be heated to the upper limit of processing temperature during hot working. In order to ensure the plasticity during processing, the final processing temperature should not be lower than 960 C when the deformation reaches 20%.
Inconel 718 Cold Processing
Cold working should be carried out after solution treatment. Inconel 718's work hardening rate is higher than that of austenitic stainless steel. Therefore, the processing equipment should be adjusted accordingly, and there should be intermediate annealing process during cold working.
Inconel 718 Heat Treatment
Different solid solution treatment and aging treatment process will lead to different material properties. Because the diffusion rate of gamma phase is low, the Inconel 718 Alloy can obtain the best mechanical properties by long time aging treatment.