ON THE MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF HIGH-SPEED STEELS

The authors have studied the role of the primary carbides on the wear of high-speed steels and found them to be of no importance, and under certain conditions contributing to higher wear rates. It has been shown analytically and experimentally that in quenched and tempered high-speed steels, the precipitation of the secondary hardening carbide (cubic M2C type) is the main reason for the improved strength and wear resistance. This shows that the secondary hardening phenomenon of high-speed steels is a direct result of the hardening caused by the precipitation of the cubic M2 C-type carbide. The present study has estimated that at peak hardness the volume fraction of secondary hardening carbide and secondarily on martensitic strengthening.