Investigation of cutting speed, recast layer and micro-hardness in angular machining using slant type taper fixture by WEDM of Hastelloy X

Abstract

Wire electric discharge machining (WEDM) is a thermo-electric spark erosion process that can machine any difficult to cut materials. Taper cutting in WEDM is a unique feature that has many problems such as taper angular inaccuracies, wire cut and distribution of dielectric fluid during machining. In the present research work, angular machining is performed for generating a tapered component using a novel slant type taper fixture which overcomes the disadvantages of taper cutting in WEDM. The machining was performed on Hastelloy X at various angles namely 0°, 30° and 60° with different parameters in the machining range. The behaviour of cutting speeds for Taguchi's L9 set of experiments at 0°, 30° and 60° angle of tilt in machining was reported. The cutting speed is ranging from 0.16 mm/min to 2.49 mm/min during angular machining. From the SEM micrographs, the highest average recast layer thickness for highest cutting speed parameter was 26.4 μm at 0° and for the lowest cutting speed parameter, it was measured 6.4 μm lowest at 60° compared to the remaining angle of cut. The variation of micro-hardness at 0°, 30° and 60° tapered components at the highest cutting speed parameter were measured using Vickers micro-hardness test. The lowest Vickers hardness was found to be 167Hv at 0°. However further it is increased to 173Hv and 180Hv at 30° and 60° angle of cut respectively. © 2019 Elsevier Ltd.