Influence of tool path strategies on friction and wear behavior of high-speed ball-end-milled hardened AISI D2 steel

Abstract

This paper aims at exploring how tool path strategies influence the friction and wear behavior of high-speed ball-end-milled hardened AISI D2 steel. High-speed hard milling (HSHM) operations were conducted on a 5-axis machining center with three different tool path strategies. Dry sliding friction and wear tests of test samples versus GCr15 rings were performed utilizing a block-on-ring tester. Results showed that friction and wear behavior were closely associated with tool paths. Though the same cutting parameters were used, there is a numerical evidence on the difference in surface integrity for different tool path conditions. Low friction coefficient was obtained for surfaces with microgroove orientation perpendicular to sliding direction. Inclination extent of grain boundary can act as a wear resistance indicator. The subsurface softening degree is the most evident factor by which tool paths influence wear behavior. It determines the way of carbide spalling and the severity of plastic deformation and then the main wear mechanisms. This study indicates that the friction and wear performance of ball-end-milled surfaces suffering from known friction loads can be improved by appropriate selection of tool path strategies.