Study on Machining of Inconel 718 Super Alloy and Effective Process Parameters Using Design of Experiment Method

Inconel alloys are a family of nickel-based superalloys that consist of a wide range of compositions and properties. Inconel 718 is one of superalloys used in the aerospace industry due to its good mechanical properties; such as high corrosion and creep resistance at high temperatures. Despite these advantages, Inconel 718 is among the most difficult materials to be machined. In this paper, a finite element model for orthogonal machining of Inconel 718 was developed in order to investigate the effective parameters on the force, temperature and chip morphology. The plastic behavior of material was simulated with Johnson-cook material model, and constant shear friction factor (m) is used to model the friction between chip and tool interface. Then, the simulation results were compared with experimental values with which a good agreement was found between them. After validating the simulation results, the effect of coefficient friction, cutting speed and rake angle, on the cutting edge temperature, force on the tool and chip morphology was achieved by using design of experiments (DOE) method. According to the results, feedrate (with 30% contribution) and friction coefficient (with 19% contribution) have the greatest impact on the force on the tool. Rake angle (with 31% contribution), cutting speed (with 21% contribution) and feedrate (with 20% contribution) are the most effective parameters on the cutting edge temperature. The friction coefficient and feedrate (both with 25% contribution) have the greatest impact on the chip geometry.