Effect of LN₂ and CO₂ Coolants in hard turning of AISI 4340 steel using tungsten carbide tool

Abstract

Recently Cryogenic cooling has witnessed a significant role in improving efficiency, increasing the quality of machined parts, and developing a techno-economic and eco-friendly acceptable methodology in the machining of components. This study deals with the effect of hardened AISI 4340 steel at 48 HRC against uncoated WC cutting tool analyzed through use of dry, cryogenic liquid nitrogen (Cryo-LN2) and cryogenic liquid carbon dioxide (Cryo-LCO2) cooling environments. The input parameters for this hard turning condition include cutting velocity, feed rate, and depth of cut. A study of the machining performance of cutting temperature, surface roughness, material side flow, flank wear, microhardness, and chips morphology has also been made. The experiment results revealed the effective lowering of the cutting temperature, better surface roughness and reduces flank wear for LCO2 and LN2 coolant by cryogenic cooling against dry cutting condition. Compared to dry and cryogenic LCO2 cutting environments, the machined zone of a cryogenic LN2 exhibited the highest microhardness value. The main reason for this was the decrease in the thermal softening effect. Overall, the performance of the cryogenic LN2 environment condition was effective and efficient in the turning process compared to dry and cryogenic LCO2.

Application of coolants during tool-based machining – A review

“…On the other hand, spraying lubrication is achieved by spraying a cold liquid that shifts the heat formed in machining operations. The heat energy from the cutting process is transferred by either warming the cold liquid or evaporating the liquid to a gaseous state [107][108][109][110][111].…”

Exploring the Impact of the Turning of AISI 4340 Steel on Tool Wear, Surface Roughness, Sound Intensity, and Power Consumption under Dry, MQL, and Nano-MQL Conditions

“…Cooling of the machining zone is of paramount importance to address the problems caused by excessive heat. Many studies have been conducted to optimize cutting parameters of AISI 4340 alloy steel and improve the quality of the machined surface [3][4][5][6]. In these studies, researchers have focused on reducing surface roughness to ensure the integrity of the machined surface, minimizing tool wear and the resulting increase in cutting forces, reducing power consumption, enhancing machining efficiency, optimizing cutting parameters such as cutting speed and feed rate, as well as controlling pa-rameters such as cooling and lubrication methods, and exploring environmentally friendly green manufacturing [7].…”