Performance of Nitrogen and Liquid Nitrogen as Coolants in Orthogonal Machining of AISI 1020 Steel Alloy With Uncoated Carbide Tools

The growing cost associated with insurance, handling and disposing of conventional metal working fluids (oil and water based) continues to drive a need for alternative metal working fluids. An orthogonal tube turning experiment was conducted to study the effects of nitrogen and liquid nitrogen in machining of AISI 1020 steel alloy on a HAAS CNC lathe along with a Kistler Dynamometer to record the force data. Two levels of uncut chip thickness, 0.002” and 0.004” per revolution are maintained with a constant feed and depth of cut of 0.125”. The tool used in this study is an uncoated carbide insert at three different rake angles of 0°, 7° and 15°, with no chip breaker. The statistical design of the experiment established the machining for a duration of 1 minute at each factor level combination. Force data from the dynamometer is analyzed along with wear of the tooling. Tool inserts were studied under a 3-dimensional optical microscope to measure the rake face tool wear. Simple nitrogen produced less wear than the more expensive liquid nitrogen setup.