For the present work, a center lathe with step variable spindle speed and feed was used. The headstock was powered by an AC motor and incorporated with a 3-jaw chuck to hold the work piece. Revolving tail stock center was used at the other end to support the work piece. A stainless steel work piece (SS202 with 241 BHN hardness, 620MPa tensile strength and 500J/kgK specific heat) of 40mm diameter and carbide insert tool (TPUN 160304) was used for the experimentation which involved plain turning of the work piece for a length of 50 mm from the initial diameter of 39mm to final diameter of 25 mm varying the speed, feed and depth of cut as per the plan of experiments. For each experiment, a fresh cutting edge was used. A KISTLER Piezo-electric dynamometer was mounted on the tool post for the on-line measurement of the cutting force. After each experiment, a tool room microscope was used to measure tool flank wear. Experiments were carried out both in dry condition and in cryogenic environments using liquid nitrogen which was supplied to the tool tip under 5kg/cm2 pressure using a specially designed nozzle. Experimental setup is shown in Fig. 1.
Flank wear in cryogenic cutting,
LWC = 0.2558 + 0.0662N + 0.0389f + 0.0282d + 0.0062N2
+0.0046f2+ 0.0008d2+ 0.0130Nf + 0.01Nd
+0.0066fd (1)
Flank wear in dry cutting,
LWD = 0.3693 + 0.0754N + 0.0512f + 0.0248d + 0.0028N2
+0.0118f2+ 0.0058d2+ 0.0164Nf
+0.0020Nd + 0.0056fd