Empirical modeling of machining parameters during WEDM of Inconel 690 using response surface methodology

Abstract

Machining of superalloy is an active research area due to extensive use of these materials. Inconel 690 is a high-chromium nickel superalloy that offers high hardness and outstanding resistance to corrosion at elevated temperatures, good creep -rupture strength, excellent resistance to oxidizing chemicals and stress-corrosion cracking. This current alloy's protection from gases containing sulfur content makes it ideal material for various applications viz. coalgasification units, petrochemical processing furnaces, equipment for radioactive waste disposal, recuperators and incinerators. Thus, this alloy is extensively used in tubes for steam generator, and equipment in nuclear applications, however, the intrinsic issues experienced during processing of superalloys using traditional methods demand the application of alternative processing techniques. Wire electrical discharge machining (WEDM) process is taken as one of the potential alternatives to traditional processing techniques, however there is inadequate information and appropriate models to foresee the WEDM process performance specifically for Inconel 690. In the present research, experimental modeling of the WEDM input factors was performed for Inconel 690 using response surface methodology (RSM). Input factors viz. pulse-on time (Ton), pulse-off time (Toff), peak-current (IP) and spark-gap voltage (SV) have been considered as process factors keeping other factors constant. The output parameters taken into consideration are cutting rate (CR) and surface roughness (SR). The research findings, and data generated for Inconel 690 will really be beneficial for the industry.