In the earlier study the wear and metal removal in single grain wear test have been investigated on many grain-work combinations. On the other hand, a series of plain fly milling test have been made to evaluate the resistance of grain to micro-chipping on the same grains and works, but in this research the metal removal, or
G-ratio, has never estimated. In the present paper the numerical results of the
G-ratio are presented, which were obtained based on the previous experimental data on micro-chipping characteristic, provided that grain is a sphere. The ratio was determined as a function of depth of cut. From the result of
G-ratio, the rating and the compatibility of grain to work have been discussed. The results obtained are summarized as follows : The
G-ratio is seen to increase at first with depth of cut and reach a maximum at a depth of cut of 20 to 40μm. The maximum
G-ratio ranges from 400 to 7000 in compliance with grain and work material. Specially, the grain type appears to much effective on the
G-ratio. Roughly speaking, it is evident that the grain types of having high hardness and medium toughness, such as the 40 SH, the SH or the R 71 grains, have higher
G-ratio than the highly friable grain types, the WA or the 2 A grains, and also highly soft grain, the AZ 40 grain, with the exception of the SUS 27 steel, where the tougher grain indicates higher
G-ratio.
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