US4055448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferrite-austenite stainless steel
Assignee: Daido Steel Co Ltd
•
Filing: 1976-05-14
•
Granted: 1977-10-25
•
Expires: 1996-05-14
Abstract
Abstract Disclosed is an improved stainless steel in ferrite-austenite condition caused by solution heat treatment at a temperature of 1000° - 1150° C, composed of by weight percent, carbon up to 0.06%, silicon up to 1.0%, manganese up to 1.5%, nickel from 3.0% to 7.0%, chromium from 21.0% to 28.0%, copper up to 3.0%, molybdenum from 1.0% to 4.0%, boron from 0.0008% to 0.0080%, niobium from 0.08% to 0.7%, titanium from 0% to 0.5%, tantalum from 0% to 0.5%, zirconium from 0% to 0.5%, nitrogen up to 0.1%, and the remainder of iron and an inevitable amount of impurity, with the values of nickel equivalent and chromium equivalent calculated by the following equations: Nickel equivalent = 40(carbon % + nitrogen %) + 3(nickel %) + (copper %) + 2(manganese %) Chromium equivalent = (chromium %) + 5.2(silicon %) + 4.2(molybdenum %) + 4.5(niobium %) + 7.0(titanium %) + 3.0(tantalum %) + 13.0(zirconium %) Satisfying the relationship below: Nickel equivalent = from 15 to 30 Chromium equivalent = from 28 to 50 Chromium equivalent -- nickel equivalent = from 8 to 27.
Inventors
- 👤 Masakuni Fujikura
- 👤 Naohiro Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:59
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/44; C22C38/54
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
188 words
An improved stainless steel in ferrite-austenite condition said ferrite-austenite condition being produced by solution heat treatment at a temperature of 1000 ° -1150 ° C, and composed of, by weight percent, carbon up to 0.06%, silicon up to 1.0%, manganese up to 1.5%, nickel from 3.0% to 7.0%, chromium from 21.0% to 28.0%, copper up to 3.0%, molybdenum from 1.0% to 4.0%, boron from 0.0008% to 0.0080%, niobium from 0.08% to 0.7%, titanium from 0% to 0.5%, tantalum from 0% to 0.5%, zirconium from 0% to 0.5%, nitrogen up to 0.1%, and the remainder of iron and an inevitable amounts of impurity, with the values of nickel equivalent and chromium equivalent calculated by the following equations: nickel equivalent = 40 (carbon % + nitrogen %) +3 (nickel %) + (copper %) +2 (manganese %) chromium equivalent = (chromium %) + 5.2 (silicon %) +4.2 (molybdenum %) + 4.5 (niobium %) +7.0 (titanium %) + 3.0 (tantalum %) +13.0 (zirconium %) satisfying the relationship below: nickel equivalent = from 15 to 30 chromium equivalent = from 28 to 50 chromium equivalent -- nickel equivalent = from 8 to 27.
Claim 2
Dependent Claim
188 words
An improved stainless steel in ferrite-austenite condition said ferrite-austenite condition being produced by solution heat treatment at a temperature of 1000 ° -1150 ° C, and composed of, by weight percent, carbon up to 0.06%, silicon up to 1.0%, manganese up to 1.5%, nickel from 3.0% to 7.0%, chromium from 21.0% to 28.0%, copper up to 3.0%, molybdenum from 1.0% to 4.0%, boron from 0.0008% to 0.0080%, niobium from 0.08% to 0.7%, titanium from 0% to 0.5%, tantalum from 0% to 0.5%, zirconium from 0% to 0.5%, nitrogen up to 0.1%, and the remainder of iron and an inevitable amounts of impurity, with the values of nickel equivalent and chromium equivalent calculated by the following equations: nickel equivalent = 40 (carbon % + nitrogen %) +3 (nickel %) + (copper %) +2 (manganese %) chromium equivalent = (chromium %) + 5.2 (silicon %) +4.2 (molybdenum %) + 4.5 (niobium %) +7.0 (titanium %) + 3.0 (tantalum %) +13.0 (zirconium %) satisfying the relationship below: nickel equivalent = from 15 to 30 chromium equivalent = from 28 to 50 chromium equivalent -- nickel equivalent = from 8 to 27.
Claim 3
Dependent Claim
14 words
The improved steel of claim 1 having a copper content of up to 0.3%.
Claim 4
Dependent Claim
189 words
An improved stainless steel in ferrite-austenite condition, said ferrite-austenite condition being produced by solution heat treatment at a temperature of 1000 ° -1150 ° C, and composed of, by weight percent, carbon up to 0.06%, silicon up to 1.0%, manganese up to 1.5%, nickel from 3.0% to 7.0%, chromium from 21.0% to 28.0%, copper from 0.8% to 2.0%, molybdenum from 1.0% to 4.0%, boron from 0.0008% to 0.0080%, niobium from 0.08% to 0.7%, titanium from 0% to 0.5%, tantalum from 0% to 0.5%, zirconium from 0% to 0.5%, nitrogen up to 0.1%, and the remainder of iron and an inevitable amounts of impurity, with the values of nickel equivalent and chromium equivalent calculated by the following equations: nickel equivalent = 40 (carbon % + nitrogen %) +3 (nickel %) + (copper %) +2 (manganese %) chromium equivalent = (chromium %) + 5.2 silicon %) +4.2 (molybdenum %) + 4.5 (niobium %) +7.0 (titanium %) + 3.0 (tantalum %) +13.0 (zirconium %) satisfying the relationship below: nickel equivalent = from 15 to 30 chromium equivalent = from 28 to 50 chromium equivalent -- nickel equivalent = from 8 to 27.
Claim 5
Dependent Claim
189 words
An improved stainless steel in ferrite-austenite condition, said ferrite-austenite condition being produced by solution heat treatment at a temperature of 1000 ° -1150 ° C, and composed of, by weight percent, carbon up to 0.06%, silicon up to 1.0%, manganese up to 1.5%, nickel from 3.0% to 7.0%, chromium from 21.0% to 28.0%, copper from 0.8% to 2.0%, molybdenum from 1.0% to 4.0%, boron from 0.0008% to 0.0080%, niobium from 0.08% to 0.7%, titanium from 0% to 0.5%, tantalum from 0% to 0.5%, zirconium from 0% to 0.5%, nitrogen up to 0.1%, and the remainder of iron and an inevitable amounts of impurity, with the values of nickel equivalent and chromium equivalent calculated by the following equations: nickel equivalent = 40 (carbon % + nitrogen %) +3 (nickel %) + (copper %) +2 (manganese %) chromium equivalent = (chromium %) + 5.2 silicon %) +4.2 (molybdenum %) + 4.5 (niobium %) +7.0 (titanium %) + 3.0 (tantalum %) +13.0 (zirconium %) satisfying the relationship below: nickel equivalent = from 15 to 30 chromium equivalent = from 28 to 50 chromium equivalent -- nickel equivalent = from 8 to 27.
References Cited (Backward Citations)
US2750283A
Cited
US3306736A
Cited
US3352666A
Cited
US3499802A
Cited
US3567434A
Cited
US3740213A
Cited
US3926685A
Cited
US3856515A
Cited
US3795507A
Cited
US3865644A
Cited
US3785787A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |