Abstract
Followlng the 8th report, the effects of Ti, Zr, U, Mo, Cr and Mn on the hardness microscopic and cutting tests of the standard tungsten carbide series tools made by the special deviced apparatus were investigated.
Moreover, the effects of the repeated tempering on the expansion, microscopic, cutting and hardness tests at room and high temperatures of the various high speed steels were investigated. In general, the results of investigations showed that the repeated tempering at short time of the high speed steels were superior to the continuous tempering at long time.
