Experimental and numerical investigation of Inconel 718 machining with worn tools

Nickel based superalloy is widely used in safety critical areas and its machined surface integrity is considered as one of the most important aspects regarding their work performance. Due to the reality that most of the machined surface is actually generated with tools in the worn condition because of the rapid worn when machining these kinds of materials, it is essential to understand the machining performance with worn tools. In the present investigation, both numerical and experimental methods are employed to study the cutting process when machining Inconel 718 with worn tools, including chip formation, force variation, tool wear and thermal distribution, as well as the acquired subsurface microstructure and mechanical characteristics. The results clearly shows the influence from wear tool at difference cutting speeds on the thermal distribution, force variation and tool flank wear performance. Obvious white layer appeared on the subsurface is believed because of the existing of the tool wear which causes the intense of friction in the tool-surface contact and significant heat generation changing the stress condition and thermal distribution. The EBSD and SEM results also clearly present the subsurface material alternation and deformation difference in various cutting conditions. The similar findings acquired from the numerical results not only shows good coherence with the experimental study, but also emphasize the ability to investigate the cutting performance with worn tools in numerical way, which can reduce the needed resource and study the deformation in generated surface properties rapidly.