Case-hardening method for carbon steel
Abstract
Abstract A case-hardening method for forming a hardened layer on the surface of carbon steel of high toughness and hardness is provided which comprises forming a powdered mixture of titanium in an amount of 5 to 30% by weight of said mixture, chromium in an amount such that the weight ratio of chromium to titanium is within the range of 2 to 10, alumina and a catalyst, embedding carbon steel in said powder mixture, and then subjecting said mixture to a heat treatment to form a hardened layer mainly composed of titanium carbide. The method may also be carried out by coating the surface of carbon steel with alumina, preparing a powder mixture containing titanium in an amount of 5 to 30% by weight of said mixture chromium in an amount such that the weight ratio of chromium to titanium is within the range of 2 to 10, alumina and a catalyst, then embedding said alumina-coated carbon steel in said powder mixture, and then subjecting said mixture to a heat treatment to form a hardened layer mainly composed of titanium carbide.
Inventors
- 👤 Hiroshi Hashimoto
- 👤 Kiyomitsu Suga
- 👤 Toshio Shimizu
Bibliographic Details
Claims Analysis
Total Claims: 6References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |