Quality-productivity decision making when turning of Inconel 718 aerospace alloy: A response surface methodology approach

Abstract

Inconel 718 is among difficult to machine materials because of its abrasiveness and high strength even at high temperature. This alloy is mainly used in aircraft and aerospace industries. Therefore, it is very important to reveal and evaluate cutting tools behavior during machining of this kind of alloy. The experimental study presented in this research work has been carried out in order to elucidate surface roughness and productivity mathematical models during turning of Inconel 718 superalloy (35 HRC) with SiC Whisker ceramic tool at various cutting parameters (depth of cut, feed rate, cutting speed and radius nose). A small central composite design (SCCD) including 16 basics runs replicated three times (48 runs), was adopted and graphically evaluated using Fraction of design space (FDS) graph, completed by a statistical analysis of variance (ANOVA). Mathematical models for surface roughness and productivity were developed and normality was improved using the Box-Cox transformation. Results show that surface roughness criterion Ra was mainly influenced by cutting speed, radius nose and feed rate, and that the depth of cut had major effect on productivity. Finally, ranges of optimized cutting conditions were proposed for serial industrial production. Industrial benefit was illustrated in terms of high surface quality accompanied with high productivity. Indeed, results show that the use of optimal cutting condition had an industrial benefit to 46.9 % as an improvement in surface quality Ra and 160.54 % in productivity MRR.

Modeling and Optimization of Cutting Parameters When Turning EN-AW-1350 Aluminum Alloy

“…Three optimization operations have been carried out in terms of quality, productivity, and qualityproductivity [28][29][30]. The first procedure consists on finding out the minimum of the surface roughness, while the second seeks the maximum of the material remove rate.…”

Anomalies in the Geometric Surface Structure of Shaped Elements Composed of Inconel 718 Alloy

“…Due to its mechanical and physical properties, such as high strength [3] and creep resistance at high temperatures, it is widely used in the aircraft and aerospace industries, as well as in gas turbines and nuclear reactors [4][5][6][7]. The numerous advantages of this alloy result in it being used in extraordinarily severe conditions, such as those inside the combustion chamber of an aircraft engine [8,9], where heat resistance [10,11] and precision of the manufacturing of parts are extremely important, because they influence the safety of passengers during flight. Due to the price of Inconel and machining difficulties [12,13], it is used only where conditions require it.…”