機械構造用鋼の被削性におよぼす微量元素低減の影響

抄録

The effect of a decreased content of impurities in steel on machinability was studied by meam of turning tests using cemented carbide tools. Low-carbon boron steels and medium-carbon steels were used as the work materials. The machined surfaces were examined by the use of a scanning electron microscope and an electron probe micro analyzer. The results of the investigation show that imperfections such as voids on the surface layer are produced even when workpieces are machined at high speeds without built-up edges. It is shown that the void formation is associated with inclusions and the occurrence of voids is reduced with a decreased content of inclusions. It is found that the surface damage decreased during the machining of calcium deoxidized free-machining steels owing to the formation of a nonmetallic layer on the tool flank.