Finish Hard Turning of Powder Metallurgy M50 Steel
Y K. Chou, Christopher J. Evans
Finishing performance in turning of hardened powder metallurgy (PM) AISI M50 steel using cubic boron nitride (CBN) tools has been studied. Tool wear and flank wear rates are unusually small and are relatively insensitive to cutting conditions. This is presumably due to the refined transition metal carbides in the workpieces which tend to reduce chemical reactivity during cutting and minimize abrasive wear of cutting tools. Surface finish obtained at a fine feed and small depth of cut is in the range of 60 nm to 120 nm Ra. Cutting chips examined show that segment spacing increases with cutting speed, probably asymptotically, and is nearly linear with the maximum undeformed chip thickness. The results also suggest the potential of using PM steels for machinability enhancement in high speed finishing of hardened dies and molds.
Transactional Analysis Journal
CBN tools, Hard turning, Manufacturing Processes, Tool wear