Effects of turning speed on high-speed turning by ultrafine-grained ceramic tool based on 3D finite element method and experiments

Abstract

In this paper, 3D computational models of turning process of alloy steel AISI4340 by nano Al2O3 tool with different turning speeds are studied. Simulations results are utilized to predict the evolutions of turning forces, temperatures, and tool wear in tools. Coupled thermo-mechanical FEM model of turning incorporating the material properties and simulation conditions (initial and boundary) are applied. Theories of heat generation in metal turning have been discussed. The flow stress–strain data of the AISI1013 were obtained from the material library in DEFORM-3D software. Microstructures of nano- and commercial micron-sized Al2O3 have been observed. The effects of turning speed on the temperature distribution have been researched. The temperatures of workpiece increase with the rise of turning speeds. The temperatures of workpiece and tool may remain stable when stable cutting stage reached. The reason of the turning forces decrease is due to the workpiece metal softens for temperature rise. The reason of tool breakage is the abruptly increasing turning force in the Y-direction. The crater wear is normally the dominating wear mode during the high-speed turning. Diffusion wear plays a major role in crater wear. The reasons of wear dropping with speed increase are temperature rise of workpiece and flow stress dropping. The reasons of wear rise with speed increase are increase of turning forces. The measures to decrease the failures of turning tools have been put forward.