Performance evaluation of CrAlNAg-coated inserts with varying Ag content during roughing and finishing operations in face milling.

The performance of a novel hard solid lubricant coating, CrAlNAg, in the face milling operation of AISI 1045 medium carbon steel under the modes of roughing and finishing was investigated. Dry machining was carried out using CrAlN coated inserts with varying silver (Ag) contents ranging from 0 to 16 at.%. The objective was to evaluate the performance of the developed coatings under different machining conditions, which could potentially result in (a) a high material removal rate (rough machining) and (b) high surface finish and dimensional accuracy (finish machining). An in-depth analysis of the cutting forces in face milling was performed to assess the impact of the coatings under these machining conditions. During machining, the force components in the X, Y, and Z directions were measured using a cutting force dynamometer attached to the workpiece. The components of these forces concerning the tool edge were calculated using geometrical characteristics and mathematical formulations, enabling the identification of the true cutting forces and the most sensitive force components relative to the cutting parameters. Apart from cutting forces, chip temperature, tool wear, surface roughness, and chip characteristics were evaluated for different coating compositions under both machining conditions. Owing to superior coating-substrate adhesion and tribological characteristics, the CrAlNAg9 coating with around 8.6 at.% of Ag was found to significantly reduce dominant forces and chip temperature under both machining conditions. Furthermore, the same coating exhibited remarkable resistance to flank wear compared to other compositions of CrAlNAg coatings. [ABSTRACT FROM AUTHOR]