抄録
1. In early days of automobile manufacture, in Japan, U.S.A. and England, high alloy steels were used to make automobile parts. But afterwards, developments of design of automobile parts, to-gether with more accurate manufacture and finer surface finish, have greatly improved the service life of automobile parts.
This resulted in very much less accent on the importance of basic alloy composition, so that the available lower cost, lower alloy grades could, with the highly developed heat-treating control and investigation on the hardenability of steels, be used interchangeably for automotive applications.
2. The author investigated and compared the grades of steels made in Japan, U.S.A. and England, concerning not only the kind of steels but also a quantity of incidental alloying elements, non-metallic inclusions and the grain size in steel.
The result of comparison showed that, grade of automotive steels made in U.S.A was the best of all and steels made in Japan was, to a great regret, the poorest of all.
