Metallographic Analysis of the Cutting Zone and Comparison with Numerical Simulation

In the paper the detailed structural changes in the cutting zone were determined using metallography. Accurate determination of parameters such as shear angle, slip angle, chip thickness, cutting ratio, chip separation point, etc. required metallographic analysis on a relatively complex sampling of the cutting area. We performed the analysis on an orthogonal cutting. We achieved orthogonal cutting by turning a thin-walled Inconel 718 and C45 alloy tubes and setting the lath bit cutting edge perpendicular to the tube axis. In real state, the shapes in the cutting zone are more complicated therefore the chip thickness was determined using quantitative metallography from the equality of areas and the resulting point of transition between the chip and the machined surface. The shear angle starts from this point and is a tangent to the cutting edge, the direction of which was determined using the Thales circle. The distance between this point and the machined surface which represents a layer which is not separated from the machined material but is planar deformed was determined too. The depth of the deformed layer and the value of deformation on the machined surface was determined by quantitative metallography. A much simpler numerical simulation was performed with the same parameters using Deform 2D/3D software package. Numerical simulation could not fully replace metallographic analysis, but to some extent numerical simulation can be used instead of metallographic analysis.