Application of minimum quantity GnP nanofluid and cryogenic LN2 in the machining of Hastelloy C276

Abstract

The current study delves into the combined influence of lubrication and cooling on the machinability of a difficult-to-cut superalloy. A comparative study of four lubricating mediums—dry, Minimum Quantity Lubrication (MQL), nanoMQL (NMQL), and Cryo-NMQL—was conducted during the milling of Hastelloy C276. Findings reveal that the Cryo-NMQL medium resulted in a 25.49%, 29.84%, and 42.50% decrease in cutting force, cutting temperature, and surface roughness, respectively, compared to dry cutting. This lubricating medium also decreased tool wear by 44.55%, as confirmed by SEM images showing reduced adhesion and abrasion. Analysis of chip morphology indicated a finer lamella structure with minimal serration under Cryo-NMQL, indicating enhanced efficiency. Furthermore, Cryo-NMQL refined the grain structure, enhancing microhardness for improved superalloy machining. ANOVA analysis identified feed rate and cutting speed as the most impactful parameters affecting the machining responses. Lastly, based on MORSM analysis, optimal machining parameters were determined as a cutting speed of 76.60 m/min, feed rate of 0.12 mm/tooth, radial depth of cut of 6.7 mm, and axial depth of cut of 0.6 mm. Experimental and predicted values closely matched, with a composite desirability score of 0.912, showcasing the efficacy of MORSM in addressing machining difficulties. This holistic investigation underscores Cryo-NMQL as a promising solution for the efficient and effective machining of superalloys.