HARD MACHINING OF P235GH STEEL WITH DIFFERENT PARAMETERS USING GSRS MODELLING

The high-strength and heat-resistant P235GH steel finds wide applications in pressure vessels and heat exchangers. It is a difficult-to-handle material, which reduces the life of the tool during machining, hence spoiling the finish of machined surface. Cutting fluids can improve the life of tools and surface finish. The current investigation observes the effect of machining parameters (revolution and feed rate) and different cutting environments (SAE-40 oil with 5 % boric acid, soybean oil and nanofluid) on the surface finish and flank wear in hard turning of P235GH steel. Machining trials are designed using an L18 orthogonal array with replications. A hybrid approach of grey system based response surface (GSRS) modelling is employed to study the effects of various parameters and their interactions. The chip morphology and flank wear are analysed using scanning electron microscopic images and the predicted optimal machining condition for a better surface finish and reduced tool wear is also validated.