eva‎luation of the performance of different cooling methods on surface quality an‎d tool wear in milling GTD 450 alloy

9/22/2026 12:00:00 AM

In advanced industries such as aerospace an‎d energy production, the deman‎d for high-performance materials capable of withstan‎ding harsh operating conditions (high temperature an‎d stress) is ever-increasing. GTD 450 precipitation-hardening martensitic stainless steel is one such strategic material that, due to its outstan‎ding mechanical an‎d thermal properties, has found widespread application in the manufacturing of gas turbine blades. However, these very desirable properties have made the machining of this alloy a highly difficult an‎d costly process, accompanied by rapid tool wear. Therefore, selec‎ting an optimal cooling an‎d lubrication strategy to improve the machining process of this material is of high scientific an‎d industrial importance. The present study was conducted with the aim of eva‎luating the performance an‎d comprehensively comparing three lubrication strategies: dry, wet, an‎d Minimum Quantity Lubrication (MQL) on two key output characteristics, namely surface quality (using Ra roughness index) an‎d tool wear (using VB flank wear index) , in the face milling process of GTD 450 alloy. For this purpose, a custom experimental design based on the Taguchi method with 27 experiments was designed an‎d executed, in which the effect of main machining variables including spindle speed, feed rate, an‎d depth of cut, each at three levels, was investigated under all three lubrication conditions. The experimental results were analyzed using advanced statistical tools such as Analysis of Variance (ANOVA) an‎d Response Surface Methodology (RSM). The analyses clearly showed that the MQL method decisively an‎d significantly demonstrated the best performance in both reducing tool wear an‎d improving surface quality, an‎d was identified as the superior strategy for machining this alloy. ANOVA revealed that for surface roughness, feed rate is the most dominant influencing factor, while for tool wear, lubrication conditions followed by feed rate have the greatest impact. Quadratic regression models with very high accuracy (R2 > 98%) were developed to predict both output responses. Finally, using a multi-objective optimization method based on the desirability function, the optimal machining conditions were determined. Results indicated that for both approaches (achieving maximum quality an‎d balancing quality an‎d productivity) , the MQL method combined with a feed rate of 800 mm/min an‎d a depth of cut of 2 mm yields the best performance. Also, spindle speeds of 1063 an‎d 925 rpm were identified as optimal values for these two approaches, respectively, confirming the superiority of the MQL method in achieving the research objectives. This research adds valuable new experimental data to the technical literature an‎d provides practical guidelines for the sustainable an‎d economic improvement of the GTD 450 alloy machining process.

سايش ابزار , كيفيت سطح , بهينه‌سازي , روش سطح پاسخ , روانكاري با حداقل مقدار سيال

tool wear , optimization , surface quality , response surface methodology , Minimum Quantity Lubrication

Hamidreza Mohamadali Dastgerdi

Seyed Ali Niknam