Machinability of some hexagonal metals

Abstract

The machinability of 99.9% magnesium was studied and was compared with those of 99.9% cadmium, 99.5% zinc and 99.5% titanium. Cutting tests were performed under the Same condition for all the samples and had the following characteristics: cutting Speed of 65-400m/min, feed of 0.04-0.32mm/rev and cutting depth of 1 and 3mm. The following results were obtained:(1) Except titanium, cutting force was hardly affected by cutting speed. The order of the samples with respect to cutting force was shown asTi>Cd_??_Zn>Mg.(2) Chip shapes of zinc and cadmium changed gradually from a flow type to a sheared type as feed increased. However, titanium always showed a flow type of chips.(3) Cutting ratios of the samples were in the following order:Mg>Cd>Zn_??_Ti.(4) Cutting temperatures depended on the samples and were expressed in the following order:Ti>Cd_??_Zn>Mg.(5) Sensitivity of cutting temperature with respect to changes of cutting speed and feed was the largest for magnesium and the lowest for titanium.