Cryogenic Turning of AISI 304 Stainless Steel with Modified Tungsten Carbide Tool Inserts

The machining of stainless steel inherently generates high cutting temperature, which not only reduces tool life but also impairs the workpiece surface quality. Conventional cooling methods are ineffective in controlling the high cutting temperature and rapid tool wear. In the present research work, the effect of liquid nitrogen as a coolant applied through holes made on the rake and flank surfaces of the PVD TiAlN coated tungsten carbide turning tool inserts of ISO CNMG 120412 MP-KC5010 on the turning of AISI 304 stainless steel is studied. The influence of cryogenic cooling on the cutting temperature, cutting force, surface roughness, and tool wear, has been compared with those of wet machining. It has been observed that in the cryogenic cooling method, the cutting temperature was reduced by 44-51%, the cutting force was decreased to a maximum of 16%, and the surface roughness was reduced by 22-34% over that of wet machining. Cryogenic cooling using liquid nitrogen reduced tool wear through the control of temperature-dependant wear mechanisms.