Inconel is considered as one the difficult to cut metal and to find out causes of why Inconel 718 is difficult to machine is a topic of research for many researcher since past many years. The availability of high-pressure cooling (HPC) of cutting tools can be very effective when machining the difficult to cut metal like Inconel 718. With high-pressure coolant, it is possible to improve machinability of Inconel 718. Analysis of Microhardness and Degree of Work Hardening (DWH) is presented in this paper while Turning Inconel 718 with High Pressure Coolant Environment. There is a sudden change in micro hardness values in region between 30 and 120 μm depths from the machined surface. After this depth the microhardness of the machine affected zone slowly approaches the bulk microhardness. The bulk microhardness is found at a depth of about 270–300 μm below the machined surface for all samples. The microhardness close to the machined surface is found in the order of 1.11 times the bulk microhardness.