| 摘要 |
A screw or a tapping screw, comprising an ultra fine structure steel having ferrite grains of 3 mum or smaller in average grain size and a nitrided layer on a surface part, wherein a strength is increased, a surface hardness is increased, and the surface hardness and an inside hardness are kept in balance, whereby a novel tapping screw and novel general screws can be provided. |
| 申请人 |
NATIONAL INSTITUTE FOR MATERIALS SCIENCE |
发明人 |
TORIZUKA, SHIRO;NAGAI, KOTOBU;KOMATSU, TAKAFUMI;MIYASHITA, NAOHISA;TAKAGI, FUMITO;MATSUZAWA, MASAAKI;MIYASAKA, YOSHIMASA;HATANO, YOSHIKI;FUJIMORI, CHIAKI;OSAKA, MASAYOSHI;UEMATSU, MASAAKI;HAMA, HAJIME |
