Finite element simulation and experimental validation of machining martensitic stainless steel using multi-layered coated carbide tools for industry-relevant outcomes

Abstract

Martensitic stainless steel is widely used where there is a need for strength, hardness, and corrosion resistance. But the machinability of this steel is difficult because of its poor thermal conductivity, as it leads to high tool wear. Application of coating on the cutting tool is one of the sustainable techniques utilized in improving the machinability of work material. But the problem in the application of the coated tool is the determination of different coating materials and the thickness of coatings, and it usually requires extensive experimental tests. Therefore finite element modelling has proved to be one of the important techniques which can be employed in evaluating the machining performance of coated cutting tools. In the current work, oblique cutting experiments, 2D, and 3D FEM simulations have been performed while machining the martensitic AISI 420 steel using the multi-layered (TiN-TiCN-Al2O3-TiN, TiN-Al2O3-TiCN-TiN) coated carbide tools and uncoated carbide tool. A tabular data material model has been utilized to model the work material. Initially, the simulation results of tangential forces obtained using 2D FE and 3D FE machining models are validated with the experimental tangential forces at a feed rate (f) of 0.14 mm/rev, depth (d) of 0.3 mm, and cutting velocity (V) of 230 m/min. It has been observed that a maximum error of 59.10% in the tangential force has been observed using the 2D FE machining model and experimental results, while a maximum error of 4.05% has been observed using the 3D machining model and experimental results. Thus it indicates that the 3D FE machining model is more suitable in the prediction of machining responses. The 3D FE machining model has been further validated with the experimental results in terms of tangential force and feeds force using the different coated and uncoated cutting tools at varying feed rates of 0.14, 0.18, 0.224, and 0.25 mm/rev and at depth d = 0.3 mm, cutting speed V = 230 m/min. A maximum error of 13.97% in the tangential force and 5% in the feed force is observed at different cutting conditions. The validated model has been further utilized to examine the influence of tool coatings and cutting parameters on the effective stress, cutting temperature, cutting power, and tool temperature. The developed 3D FE model indicates that the better machinability of martensitic AISI 420 steel can be achieved using the multi-layer TiN-TiCN-Al2O3-TiN coated tool in terms of reduction in cutting temperature, effective stress, and power consumption.