Compacted graphite iron (CGI) has become one of the most potential and promising materials for diesel engines contributing to automotive industry applications because of its outstanding mechanical properties over flake graphite iron (FGI). However, the poor machinability of CGI has hindered it to be widely employed in potential automotive industry. In this paper, a supercritical CO₂-based MQL technique was introduced to improve the machinability of CGI. The machinability of CGI was systematically evaluated considering the cutting force, cutting temperature, surface integrity and tool wear under various cutting parameters (cutting speed, feed rate, depth of cut) and machining atmospheres (i.e., dry, supercritical carbon dioxide (ScCO₂), supercritical CO₂-based minimum quantity lubrication with oil-on-water droplets cutting fluid (ScCO₂-MQL)) compared to FGI and nodular graphite iron (NGI) in the milling process. The results show that among three machining atmospheres, the lowest values regarding cutting force, cutting temperature, and surface roughness values are obtained under the ScCO₂-MQL atmosphere. Furthermore, the tool wear mechanisms were revealed to be abrasion wear and adhesion wear. The ScCO₂-MQL exhibited excellent superiority in cutting force and temperature, surface integrity, and tool life compared to dry and ScCO₂ conditions due to its outstanding cooling and lubricant effects. The results demonstrated that using the advanced ScCO₂-MQL technique can substantially improve the machinability of the compact graphite cast irons.

蠕墨铸铁 (CGI) 因其优于片状石墨铸铁 (FGI) 的优异机械性能，已成为用于汽车工业应用的柴油发动机最有潜力和前景的材料之一。然而，CGI 的可加工性差阻碍了它在潜在的汽车工业中的广泛应用。本文介绍了一种基于超临界CO ₂的MQL技术，以提高CGI的可加工性。考虑在各种切削参数（切削速度、进给率、切削深度）和加工气氛（即干燥、超临界二氧化碳 (ScCO ₂ )下）下的切削力、切削温度、表面完整性和刀具磨损，系统地评估了 CGI 的可加工性, 超临界二氧化碳与 FGI 和球墨铸铁 (NGI) 在铣削过程中相比，基于₂的最小量润滑使用油对水滴切削液 (ScCO ₂ -MQL))。结果表明，在三种加工气氛中，在 ScCO ₂ -MQL 气氛下获得的切削力、切削温度和表面粗糙度值最低。此外，工具磨损机制被揭示为磨损和粘附磨损。与干燥和 ScCO ₂条件相比，ScCO ₂ -MQL 在切削力和温度、表面完整性和刀具寿命方面表现出卓越的优势，因为它具有出色的冷却和润滑效果。结果表明，使用先进的 ScCO ₂-MQL 技术可以显着提高致密石墨铸铁的切削加工性。