US4137104A
Expired / Lapsed
US
⏱️ 0.0 years remaining
As-rolled steel plate having improved low temperature toughness and production thereof
Assignee: Nippon Steel Corp
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Filing: 1977-02-14
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Granted: 1979-01-30
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Expires: 1997-02-14
Abstract
Abstract A high strength steel plate of improved low temperature toughness useful for making an arctic grade line pipe is provided with the addition of 0.8 - 2.0% by weight of Ni and 0.0005 - 0.0040% by weight of Ca, which may be used in the as-rolled state and manufactured through two step controlled rolling the secondary step rolling of which is carried out at a temperature lower than a conventional rolling temperature.
Inventors
- 👤 Hajime Nashiwa
- 👤 Akiyoshi Mori
- 👤 Yoshiyasu Kitagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:04
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
121 words
An as-rolled steel plate having improved low temperature toughness, which consists essentially of: C: 0.03 - 0.55% by weight Si: 0.02 - 0.50% by weight Mn: 0.30 - 2.00% by weight P: not greater than 0.025% by weight S: not greater than 0.010% by weight Ni: 0.8 - 2.0% by weight Ca: 0.0005 - 0.004% by weight Nb: 0 - 0.05% by weight V: 0 - 0.10% by weight Sol. Al: not greater than 0.080% by weight Calcium/sulfur weight ratio: 0.05 - 1.50 said amounts of Ca and Ni serving to reduce the formation of bainite phase during low temperature rolling and making it possible for use of said plate as a pipe line material in the as-rolled state Fe: balance.
Claim 2
Dependent Claim
121 words
An as-rolled steel plate having improved low temperature toughness, which consists essentially of: C: 0.03 - 0.55% by weight Si: 0.02 - 0.50% by weight Mn: 0.30 - 2.00% by weight P: not greater than 0.025% by weight S: not greater than 0.010% by weight Ni: 0.8 - 2.0% by weight Ca: 0.0005 - 0.004% by weight Nb: 0 - 0.05% by weight V: 0 - 0.10% by weight Sol. Al: not greater than 0.080% by weight Calcium/sulfur weight ratio: 0.05 - 1.50 said amounts of Ca and Ni serving to reduce the formation of bainite phase during low temperature rolling and making it possible for use of said plate as a pipe line material in the as-rolled state Fe: balance.
Claim 3
Dependent Claim
192 words
An as-rolled steel plate having improved low temperature toughness which consists essentially of: C: 0.03 - 0.55% by weight Si: 0.02 - 0.50% by weight Mn: 0.30 - 2.00% by weight P: not greater than 0.025% by weight S: not greater than 0.010% by weight Ni: 0.8 - 2.0% by weight Ca: 0.0005 - 0.0040% by weight Nb: 0 - 0.05% by weight V: 0 - 0.10% by weight Sol. Al: not greater than 0.080% by weight Calcium/sulfur weight ratio: 0.05 - 1.50 Fe: balance and which is manufactured through a two step controlled rolling comprising the steps of: applying a primary rolling step by heating the steel to a temperature higher than 1000° C; rough rolling the heated steel to obtain a steel plate of a suitable intermediate thickness; reheating the rough rolled steel plate to a temperature of 800° - 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate within the temperature range of 680° - 850° C and with the total reduction in thickness being not less than 30% on the basis of the steel plate thickness when said finishing rolling is started.
Claim 4
Dependent Claim
192 words
An as-rolled steel plate having improved low temperature toughness which consists essentially of: C: 0.03 - 0.55% by weight Si: 0.02 - 0.50% by weight Mn: 0.30 - 2.00% by weight P: not greater than 0.025% by weight S: not greater than 0.010% by weight Ni: 0.8 - 2.0% by weight Ca: 0.0005 - 0.0040% by weight Nb: 0 - 0.05% by weight V: 0 - 0.10% by weight Sol. Al: not greater than 0.080% by weight Calcium/sulfur weight ratio: 0.05 - 1.50 Fe: balance and which is manufactured through a two step controlled rolling comprising the steps of: applying a primary rolling step by heating the steel to a temperature higher than 1000° C; rough rolling the heated steel to obtain a steel plate of a suitable intermediate thickness; reheating the rough rolled steel plate to a temperature of 800° - 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate within the temperature range of 680° - 850° C and with the total reduction in thickness being not less than 30% on the basis of the steel plate thickness when said finishing rolling is started.
Claim 5
Dependent Claim
43 words
An as-rolled steel plate as defined in claim 2, in which the reheating temperature of the secondary step rolling is from 900° to 1000° C; and the secondary step rolling is carried out within a temperature range of from 700° to 800° C.
Claim 6
Dependent Claim
15 words
An as-rolled steel plate as defined in claim 1, wherein Ca is 0.003% by weight.
Claim 7
Dependent Claim
15 words
An as-rolled steel plate as defined in claim 1, wherein Ca is 0.004% by weight.
Claim 8
Dependent Claim
15 words
An as-rolled steel plate as defined in claim 2, wherein Ca is 0.003% by weight.
Claim 9
Dependent Claim
15 words
As as-rolled steel plate as defined in claim 2, wherein Ca is 0.004% by weight.
References Cited (Backward Citations)
US3811873A
Cited
US3834949A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-29 | 1982-07-31 | 1983-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-29 | 1986-07-31 | 1987-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-29 | 1990-07-31 | 1991-01-30 | $7700.00 | Window Closed / Lapsed |