Abstract
Influence of silicon content of hot working tool steel (4mass%Cr-Mo-V-Ni) on machinability at milling process has been investigated. The effect of silicon was compared with that of lubricant, concerning tool life, cutting forces and temperature, chip detachment from a tool, tool damages, surface oxidization, microstructure and shapes of chip.
The observation of the chip detached from the tool by high-speed video camera showed that increasing the amount of silicon resulted in suppression of adhesion between the tool and the chips. This lubrication effect of silicon coincided with the effect of lubricant sprayed. The suppression of adhesion by increasing silicon content prolonged the tool lives, probably because the scale of Fe-Si-O formed on the surface of the chips of high silicon steel lubricated more effectively than that of Fe-Cr-O formed on the surface of low silicon steel.
