Hard Turning of AISI D4 Steel Under Dry Machining and Gas Cooling Attempt is made for the Elimination of White Layer Also Enhancement of Surface Finish

Of late, hard turning is widely accepted as an innovative and cost-effective machining solution for the hard-to-cut materials in a single machining set-up using Dry machining and other cooling medium such as liquid and solid lubricants. The hard turning provides better part quality than grinding, but hard turning surfaces are affected by the distressed surface pattern termed as white layer (WL). This WL is detrimental to the part produced by decreasing the fatigue life. Also, the surface integrity is deteriorated due to dynamic phase transformations. So, an attempt was made with super hardened AISI D4 steel turned with cubic boron nitride insert under Dry Machining, also gas mixture cooling. Noticeably, the results revealed that the dry machining didn’t eliminate WL and produced more roughness. But WL elimination and better surface finish were accomplished under Gas mixture cooling.