US4008103A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of strong tough steel plates
Assignee: Nippon Steel Corp
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Filing: 1975-09-17
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Granted: 1977-02-15
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Expires: 1995-09-17
Abstract
Abstract Strong and tough steel is prepared by heating to a temperature of 800 DEG - 1000 DEG C., preferably from 800 DEG to 950 DEG C., before the rolling step, finish rolling at temperatures within the range of from 680 DEG to 850 DEG C., preferably from 680 DEG to 800 DEG C. and with a reduction ratio in thickness of not less than 30% based on the plate thickness of the steel when the finish rolling is started. It is advantageous to provide for a pretreatment of the steel, said pretreatment including the steps of initially heating the steel to a temperature higher than 1000 DEG C., rolling the heated steel to a suitable intermediate thickness and cooling the rolled steel to a temperature lower than 650 DEG C.
Inventors
- 👤 Eiji Miyoshi
- 👤 Minoru Fukuda
- 👤 Yasuhiko Hagiwara
- 👤 Yasuhiro Asai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:42
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/04; C21; C21D; C21D8/00; C21D8/02; C21D8/0221; C21D8/0226; C22C38/14; C21D8/0247; C21D8/0263
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
153 words
A method for the manufacture of a high strength and tough steel plate from a steel comprising 0.03 - 0.30% of carbon, not more than 1.5% of silicon, 0.5 - 4.0% of manganese and the balance essentially of iron, the method 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; cooling down the rough rolled steel plate to a temperature lower than 650° C; reheating the cooled steel plate to a temperature of 800° to 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate within the range of temperature of from 680° to 850° C and with the total reduction in thickness of not less than 30% on the basis of the steel plate thickness when said finishing rolling is started.
Claim 2
Independent Claim
153 words
A method for the manufacture of a high strength and tough steel plate from a steel comprising 0.03 - 0.30% of carbon, not more than 1.5% of silicon, 0.5 - 4.0% of manganese and the balance essentially of iron, the method 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; cooling down the rough rolled steel plate to a temperature lower than 650° C; reheating the cooled steel plate to a temperature of 800° to 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate within the range of temperature of from 680° to 850° C and with the total reduction in thickness of not less than 30% on the basis of the steel plate thickness when said finishing rolling is started.
Claim 3
Dependent Claim
53 words
A method as claimed in claim 1, wherein the steel further contains at least one element selected from the group consisting of 0.02 - 0.30% of vanadium 0.05 - 1.0% of molybdenum, 0.005 - 0.20% of niobium, 0.03 - 0.20% of titanium, 0.02 - 0.20% of zirconium and 0.01 - 0.10% of tantalum.
Claim 4
Dependent Claim
33 words
A method as claimed in claim 2, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 3.0% of chromium and 0.002 - 0.01% of boron.
Claim 5
Dependent Claim
32 words
A method as claimed in claim 3, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 1.0% of copper, 0.2 - 2.0% of nickel.
Claim 6
Dependent Claim
32 words
A method as claimed in claim 2, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 1.0% of copper, 0.2 - 2.0% of nickel.
Claim 7
Dependent Claim
17 words
A method as claimed in claim 2, wherein the steel further contains 0.6 - 5.0% of nickel.
Claim 8
Dependent Claim
33 words
A method as claimed in claim 2, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 3.0% of chromium and 0.002 - 0.01% of boron.
Claim 9
Dependent Claim
32 words
A method as claimed in claim 1, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 1.0% of copper, 0.2 - 2.0% of nickel.
Claim 10
Dependent Claim
32 words
A method as claimed in claim 1, wherein the steel further contains at least one element selected from the group consisting of 0.2 - 1.0% of copper, 0.2 - 2.0% of nickel.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 1, wherein the steel further contains 0.6 - 5.0% of nickel.
Claim 12
Dependent Claim
39 words
A process as claimed in claim 1, further comprising the step of tempering the finish rolled steel plate at a temperature ranging from 500° C to 650° C for a time duration ranging from 20 minutes to 2 hours.
Claim 13
Dependent Claim
25 words
The process according to claim 1 wherein the cooled steel plate is reheated to a temperature of 800° - 950° C prior to finish rolling.
Claim 14
Dependent Claim
22 words
The process according to claim 1 wherein the finish rolling is carried out within the temperature range of 680° - 800° C.
Claim 15
Independent Claim
167 words
A method for the manufacture of a high strength an tough steel plate from a steel comprising 0.03 - 0.30% of carbon, not more than 1.5% of silicon. 0.5 - 4.0% of manganese and the balance essentially of iron, the method 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; cooling down the rough rolled steel plate to a temperature lower than 650° C; reheating the cooled steel to a temperature of 800° to 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate by several passes through rolling mill, each pass in said finish rolling being conducted within the temperature range of 680° to 850° and the total reduction in thickness during the finish rolling passes being not less than 30% on the basis of the steel plate thickness when said finish rolling is started.
Claim 16
Independent Claim
167 words
A method for the manufacture of a high strength an tough steel plate from a steel comprising 0.03 - 0.30% of carbon, not more than 1.5% of silicon. 0.5 - 4.0% of manganese and the balance essentially of iron, the method 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; cooling down the rough rolled steel plate to a temperature lower than 650° C; reheating the cooled steel to a temperature of 800° to 1000° C; and applying a secondary rolling step by finish rolling the reheated steel plate by several passes through rolling mill, each pass in said finish rolling being conducted within the temperature range of 680° to 850° and the total reduction in thickness during the finish rolling passes being not less than 30% on the basis of the steel plate thickness when said finish rolling is started.
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) | 1980-02-15 | 1980-08-16 | 1981-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-15 | 1984-08-16 | 1985-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-15 | 1988-08-16 | 1989-02-15 | $7700.00 | Window Closed / Lapsed |