Evaluation of the machinability performance of PH 13-8 Mo maraging steel used in the aerospace industry

This study focused on investigating the impacts of machining parameters on cutting force (Fc), surface roughness (Ra), cutting power (Pc), and specific cutting energy (SCE) and determining optimum machining parameters in turning PH 13-8 Mo stainless steel. For this purpose, an experimental design was set with Taguchi's L32 orthogonal array by identifying cutting parameters such as cutting speed (Vc), feed rate (f), and depth of cut (ap) at different levels. The turning tests were carried out on the CNC lathe using a coated carbide cutting tool under dry-cutting conditions. Signal/Noise (S/N) ratio and analysis of variance (ANOVA) were used to determine the impacts of cutting parameters on Fc, Ra, Pc, and SCE values obtained after turning experiments. In addition, regression analysis was performed to identify the correlation between Fc, Ra, Pc, and SCE and cutting parameters through linear and quadratic regression models. The main findings of the study are that the lowest Fc (A1B1C3), Ra (A1B1C4), Pc (A1B1C1) and SCE (A2B4C3) values were measured at 287.8 N, 0.59 µm, 697.16 W and 1549.55 J/mm3 in turning PH 13-8 Mo martensitic stainless steel. ANOVA, the most important process parameter affecting Fc, Ra, Pc, and SCE was feed rate at the rate of 85.57%, 84.93%, 71.10% and 60%. It was observed that the mathematical model findings obtained with the test results are in good agreement. In general, wear mechanisms such as adhesion, BUE, chips, crater, notch, fracture, and chipping on the cutting tool were detected in the turning of PH 13-8 Mo stainless steel.