Turning of Hardened H13 Steel with Interrupted and Continuous Surfaces using Multilayer Coated Carbide Tool

Abstract

Turning of hardened steels has been used increasingly to replace grinding/finishing operations due to the development of advanced tool materials and rigid machine tools, which can ensure the same accurate geometrical and dimensional tolerances. However, when turning of interrupted surfaces, the tool requires not only these properties but also sufficient toughness to resist impacts against work piece interruptions. In the present study, performance of multilayer hard coatings (TiC/MT-TiCN/Al2O3) on cemented carbide substrate using chemical vapor deposition (CVD) for turning of hardened AISI H13 steel (50 HRC) was evaluated. Performance evaluation of the multilayer coated carbide tool was done on the basis of tool flank wear and was supplemented by cutting force and surface roughness analyses. The results show that the thrust force and cutting force increases with increased depth of cut and feed rate, while reduces with increase in cutting speed in both continuous and interrupt cutting. The tool flank wear was influenced mainly by the cutting speed followed by feed rate. Within the investigated range, abrasion and plastic deformation were deliberated to be the active wear mechanisms for the multilayer coated carbide tool. The feed rate was the dominant factor affecting work piece surface quality. The main conclusions of this work were that in both continuous and interrupted cutting, the multilayer coated tools exhibited a better performance with respect to both tool life and workpiece surface roughness