Technoeconomic and environmental analysis of cryogenic and MQL-assisted machining of Hastelloy X

The growing significance of superalloys like Hastelloy X, particularly in critical engineering sectors such as aerospace, chemical processing, and selective biomedical equipment (e.g., surgical instruments and medical tooling), underscores the need for advancements in their manufacturing processes. In today’s era of advanced manufacturing, it is crucial to develop machining systems that are both environmentally sustainable and cost-effective. To bridge the existing gap between economic, technological, and sustainability aspects in the machining of Hastelloy X, the present research aims to shed light on this critical interplay. Experimental investigations were conducted to evaluate the performance of various cooling techniques, including dry machining, minimum quantity lubrication (MQL), and cryogenic cooling using liquid nitrogen (LN₂) and carbon dioxide (CO₂). The results revealed that cryogenic cooling with LN₂ demonstrated superior performance across technological, sustainability, and economic metrics, outperforming other methods. Specifically, LN₂ cooling during the turning of Hastelloy X led to a reduction in tool wear and surface roughness by 21.11% and 25%, respectively, over dry machining conditions. These findings highlight the potential of advanced lubrication and cooling techniques to enhance sustainable manufacturing practices, reducing resource consumption while improving machining performance, particularly for industries involving difficult-to-machine superalloys.