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Stellite is a nickel based superalloy and expansively adopted in higher temperature engineering applications. This alloy possesses better mechanical properties such as strength and hardness. Due to its lesser thermal conductivity, it is difficult to machine by conventional methods of machining. For avoiding such kind of demerits, advanced methods of machining have been introduced. Wire Electrical Discharge Machining (WEDM) is one of category of thermal energy based machining methods which is developed from the concept of Electrical Discharge Machining. This kind of machining method is preliminarily engaged for making complex shaped components especially in harder and electrically conductive materials. In this present experimental study, an endeavour has been taken to analyse the optimized process parameters for achieving better machining performance during WEDM of Stellite using Taguchi-Grey approach.

Inconel 718, a nickel based superalloy is used in all kinds of applications where outstanding strength and corrosion resistance are essential. The Inconel 718 alloys joints from sheets of 1mm thickness are fabricated using a 4 kW Nd: YAG laser welding equipment. The influence of welding speed on the weld bead ripples, weld morphology, defects and the mechanical properties are investigated. Microstructure of the weld fusion zone, Heat Affected Zone (HAZ) and the weld ripple structure were analyzed using optical microscope and the scanning electron microscope. The weldments obtained were with nominal cracks, porosity and shape imperfections that signifying Nd: YAG laser welding as an effective method for fabricating joints of Inconel 718 of thickness 1mm. The weld fusion zone consists of fine dendritic structure and HAZ is found with columnar grain structure.