Patent US4360381A successfully refreshed from Google Patents.
US4360381A
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US
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Ferritic stainless steel having good corrosion resistance
Assignee: Nippon Stainless Steel Co Ltd
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Filing: 1981-04-07
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Granted: 1982-11-23
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Expires: 2001-04-07
Abstract
Abstract A 10-35% Cr ferritic stainless steel stabilized with 0.20-1.00% of Nb wherein Nb%>/=(8xC%+2.0%) with impurities, such as carbon, nitrogen, phosphorous, oxygen and sulfur reduced to given levels is disclosed. By reducing the sulfur content to a level of not greater than 0.002%, preferably less than 0.001% or in cases where copper and/or nickel is added, to a level of not greater than 0.005%, the corrosion resistance of the resulting steel can markedly be improved. Since the ferritic stainless steel of this invention also exhibits a combination of good surface appearance and formability, it can be substituted for certain austenitic stainless steels not only as a general corrosion resistant material, but also as a material for making external automotive trims and so on.
Inventors
- 👤 Yoshio Tarutani
- 👤 Taishi Moroishi
- 👤 Masao Koike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:51
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/26
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
87 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%) and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 2
Dependent Claim
87 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%) and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 3
Dependent Claim
18 words
A ferritic stainless steel as defined in claim 1, in which sulfur is less than 0.001% by weight.
Claim 4
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 1 or 2, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 5
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 1 or 2, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 6
Dependent Claim
91 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%), Mo: 0.10-4.00% by weight, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 7
Dependent Claim
91 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%), Mo: 0.10-4.00% by weight, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 8
Dependent Claim
18 words
A ferritic stainless steel as defined in claim 5, in which sulfur is less than 0.001% by weight.
Claim 9
Dependent Claim
23 words
A ferritic stainless steel as defined in claim 5 or 6, in which molybdenum is present in an amount of 0.3-0.75% by weight.
Claim 10
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 5 or 6, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%) C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 11
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 5 or 6, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 12
Dependent Claim
102 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%) at least one of 0.30-1.00% by weight of Cu and 0.20-2.00% by weight of Ni, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 13
Dependent Claim
102 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%) at least one of 0.30-1.00% by weight of Cu and 0.20-2.00% by weight of Ni, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 14
Dependent Claim
18 words
A ferritic stainless steel as defined in claim 10, in which sulfur is less than 0.001% by weight.
Claim 15
Dependent Claim
22 words
A ferritic stainless steel as defined in claim 10 or 11, in which Cu: 0.3-0.6% by weight, and Ni: 0.2-0.6% by weight.
Claim 16
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 10 or 11, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 17
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 10 or 11, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 18
Dependent Claim
106 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%), Mo: 0.10-4.00% by weight, at least one of 0.30-1.00% by weight of Cu and 0.20-2.00% by weight of Ni, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 19
Dependent Claim
106 words
A ferritic stainless steel exhibiting improved corrosion resistance, which consists essentially of: Si: 0.01-5.00% by weight, Mn: 0.01-5.00% by weight, Cr: 8.0-35.0% by weight, Nb: 0.20-1.00% by weight wherein Nb≧(8×C%+0.20%), Mo: 0.10-4.00% by weight, at least one of 0.30-1.00% by weight of Cu and 0.20-2.00% by weight of Ni, and the balance iron with incidental impurities of which the amounts of carbon, nitrogen, phosphorous, sulfur and oxygen are as follows: C: not greater than 0.05% by weight, N: not greater than 0.05% by weight, P: not greater than 0.05% by weight, S: not greater than 0.002% by weight, and O: not greater than 0.02% by weight.
Claim 20
Dependent Claim
18 words
A ferritic stainless steel as defined in claim 15, in which sulfur is less than 0.001% by weight.
Claim 21
Dependent Claim
26 words
A ferritic stainless steel as defined in claim 15 or 18 in which Mo: 0.3-0.75% by weight, Cu: 0.3-0.6% by weight, and Ni: 0.2-0.6% by weight.
Claim 22
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 15 or 16, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 23
Dependent Claim
59 words
A ferritic stainless steel as defined in claim 15 or 16, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 24
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 7, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 25
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 7, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 26
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 12, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 27
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 12, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 28
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 17, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 15-18% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
Claim 29
Dependent Claim
57 words
A ferritic stainless steel as defined in claim 17, in which Si: not greater than 0.5% by weight, Mn: not greater than 0.5% by weight, Cr: 18.5-22.0% by weight, Nb: 0.20-0.60% by weight wherein Nb≧(8×C%+0.20%), C: not greater than 0.025% by weight, N: not greater than 0.025% by weight, and P: not greater than 0.03% by weight.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-22 | 1986-05-24 | 1986-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-22 | 1990-05-24 | 1990-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-22 | 1994-05-24 | 1994-11-23 | $7700.00 | Window Closed / Lapsed |