Abstract
The cutting efficiency of high-cobalt highspeed steels was examined on sample tools which had been prepared by proper melting, forging and heat treatment. The result of the experiment revealed the following points:
1) As concerns the cutting efficiency of the highspeed steel, the most economical composition contains about 15% Co, and about 20% W, which also meets the requirement for the saving of valuable resources such as Co and W and corresponds to the analysis of the Japanese current specification.
2) The use of vanadium is not necessary and so better to be excluded from the specification.
3) The carbon content should be determined in relation to the Co. The former should be decreased when the latter enhanced. It is not to suitable to specialy the constant amount of C as in the present specification.
4) The low-C highspeed steel is most recommended for hignspeed cutting tools. of the weld-on or brazed tipped types and precision cutting types.
5) It is most proper to decrease the Co content for saving the valuable metal. However, the present study suggests an alternative whether to save Co or to enhance its content together with the increase of the C, thus improving the cutting efficiency and bettering the ease in hot working.
