Abstract:
The research aims were: 1) to study the influence of liquid nitrogen in terms of cutting fluids for the metal cutting processes applied in order to reduce a cutting temperature that is a key factor in wear mechanism of the cutting tools, and 2) to minimize toxin on environment created by the cutting fluids. The liquid nitrogen was applied in the turning processes of the sus420 stainless steels, which is available with the diameter of 25 mm, with a pressure of 2 bars.
The experiments were conducted using three levels of the cutting speed and feed rate at 60, 120, and 180 m/min, and 0.07, 0.14, and 0.21 mm/rev, respectively. Moreover, the depth of cut and cutting range were set at 1 mm and 1,500 mm. The output parameters were the wear of the cutting tools, surface roughness of the work piece, cutting force and cutting temperature of the cutting processes with and without cutting fluids, and with liquid nitrogen as the cutting fluids in the cutting processes.
The experimental findings indicated that using liquid nitrogen as cutting fluid provided the lowest surface roughness and wear of the cutting tools in average at 1.56 and 40.65 micron, respectively. Since the cutting temperature in the cutting processes using liquid nitrogen as the cutting fluid was the lowest, this would also decrease the surface roughness and wear of the cutting tools. Moreover, using the liquid nitrogen resulted in a higher cutting force in comparison to a normal cutting fluid, but lower than the dry cutting processes. The liquid nitrogen could lower the temperature of the work piece materials to below the freezing point which resulted in decrease of toughness but increase of hardness in work piece materials. According to this, a higher cutting force was required in order to accomplish the cutting processes in comparison to other cutting fluids.