| 摘要 |
A stainless steel bearing component (A) containing in excess of 11 % chromium and between 0.05 % and 0.50 % carbon is case-hardened by introducing carbon or nitrogen into the surface of the race using a plasma process. The component is placed in a vacuum chamber. Using the component at elevated temperature as a cathode, hydrogen is introduced into the chamber and ionized, whereupon hydrogen ions bombard the component and clean its surface. A gas containing carbon and/or nitrogen is introduced into the chamber where it exists at a pressure of 2-9 torr. A plasma is produced intermittently and deposits carbon and/or nitrogen onto the component, causing it to diffuse from the surface inwardly. Thereafter, the component is cooled, heated to transform the steel in the core to austenite, and then quenched. The quench is followed by cryogenic cooling to convert retained austenite into martensite. After assuming ambient temperature, the component is again heated to temper the hardened case. |
