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US4397697A
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Hot strips or heavy plates from a denitrated steel and method for their manufacture
Assignee: Stahlwerke Pein Salzgitter AG
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Filing: 1980-12-03
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Granted: 1983-08-09
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Expires: 2000-12-03
Abstract
Abstract An improved method for the manufacture of hot strips or heavy plates from a denitrated steel composed of 0.04 to 0.16% carbon, 1.25 to 1.90% manganese, 0.2 to 0.55% silicon, 0.004 to 0.020% phosphorus, 0.002 to 0.015% sulfur, 0.02 to 0.08% aluminum, 0.02 to 0.08% niobium, the remainder iron and possibly contaminants, including the steps of having the hot strips or plates leaving the last finishing stand of rolls at a temperature of 750° C. to 820° C., cooling the hot strips or plates to an intermediates temperature of 450° C. to 500° C. at a cooling rate of 2° to 10° C./s and then slowly cooling the hot strips or plates in air to room temperature in a coil or in a pile.
Inventors
- 👤 Klaus Freier
- 👤 Constantin M. Vlad
- 👤 Klaus Hulka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:15
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/0221; C21D8/0226; C22; C22C; C22C38/00; C22C38/04; C21D8/0247; C21D8/0263
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
126 words
In a method for the manufacture of hot strips or heavy plates from a denitrated steel composed of 0.04 to 0.16% carbon, 1.25 to 1.90% manganese, 0.2 to 0.55% silicon, 0.004 to 0.020% phosphorus, 0.002 to 0.015% sulfur, 0.02 to 0.08% aluminum, 0.02 to 0.08% niobium, the remainder iron and possibly contaminants, the improvement comprising the steps of having the hot strips or plates leaving the last finishing stand of rolls at a temperature of 750° C. to 820° C., cooling the hot strips or plates to an intermediate temperature of 450° C. to 500° C. at a cooling rate of 2° to 10° C./s and then slowly cooling the hot strips or plates in air to room temperature in a coil or in a pile.
Claim 2
Dependent Claim
126 words
In a method for the manufacture of hot strips or heavy plates from a denitrated steel composed of 0.04 to 0.16% carbon, 1.25 to 1.90% manganese, 0.2 to 0.55% silicon, 0.004 to 0.020% phosphorus, 0.002 to 0.015% sulfur, 0.02 to 0.08% aluminum, 0.02 to 0.08% niobium, the remainder iron and possibly contaminants, the improvement comprising the steps of having the hot strips or plates leaving the last finishing stand of rolls at a temperature of 750° C. to 820° C., cooling the hot strips or plates to an intermediate temperature of 450° C. to 500° C. at a cooling rate of 2° to 10° C./s and then slowly cooling the hot strips or plates in air to room temperature in a coil or in a pile.
Claim 3
Dependent Claim
17 words
Method according to claim 1, wherein the steel is alloyed with 0.02 to 0.10% addition of vanadium.
Claim 4
Dependent Claim
148 words
In a method for the manufacture of hot strips or heavy plates from a denitrated steel composed of 0.04 to 0.16% carbon, 1.25 to 1.90% manganese, 0.02 to 0.55% silicon, 0.004 to 0.020% phosphorus, 0.002 to 0.015% sulfur, 0.02 to 0.08% aluminum, 0.02 to 0.08% niobium, as well as addition of 0.15 to 0.35% molybdenum, 0.10 to 0.30% chromium and/or 0.30 to 0.90% nickel, alone or in combination, the remainder iron and possibly contaminants, the improvement comprising the steps of having the hot strips or plates leaving the last finishing stand of rolls at a temperature of 750° C. to 850° C., cooling the hot strips or plates to an intermediate temperature of 450° C. to 500° C. at a cooling rate of 2° to 10° C./s and then slowly cooling the hot strips or plates in air to room temperature in a coil or in a pile.
Claim 5
Dependent Claim
148 words
In a method for the manufacture of hot strips or heavy plates from a denitrated steel composed of 0.04 to 0.16% carbon, 1.25 to 1.90% manganese, 0.02 to 0.55% silicon, 0.004 to 0.020% phosphorus, 0.002 to 0.015% sulfur, 0.02 to 0.08% aluminum, 0.02 to 0.08% niobium, as well as addition of 0.15 to 0.35% molybdenum, 0.10 to 0.30% chromium and/or 0.30 to 0.90% nickel, alone or in combination, the remainder iron and possibly contaminants, the improvement comprising the steps of having the hot strips or plates leaving the last finishing stand of rolls at a temperature of 750° C. to 850° C., cooling the hot strips or plates to an intermediate temperature of 450° C. to 500° C. at a cooling rate of 2° to 10° C./s and then slowly cooling the hot strips or plates in air to room temperature in a coil or in a pile.
Claim 6
Dependent Claim
17 words
Method according to claim 3, wherein the steel is alloyed with 0.02 to 0.10% addition of vanadium.
Claim 7
Dependent Claim
18 words
Method according to claim 3 or 4, wherein the finishing temperature lies between 750° C. and 820° C.
Claim 8
Dependent Claim
16 words
Method according to claim 3, wherein the steel includes an addition of 0.002 to 0.08% zirconium.
Claim 9
Dependent Claim
16 words
Method according to claim 3, wherein the steel includes an addition of 0.004 to 0.051% cerium.
Claim 10
Dependent Claim
15 words
Hot strips or heavy plates manufactured according to the method of claim 1 or 3.
Claim 11
Dependent Claim
16 words
Hot strips or heavy plates according to claim 8, wherein the steel exhibits a ferritic-perlitic structure.
Claim 12
Dependent Claim
21 words
Hot strips or heavy plates according to claim 8, wherein the ratio of Cvmax to Cv100 lies between 1.0 and 1.3.
Claim 13
Dependent Claim
21 words
Hot strips or heavy plates according to claim 8, wherein the ratio of Cvmax to Cv100 lies between 1.3 and 2.0.
Claim 14
Dependent Claim
26 words
Hot strips or heavy plates according to claim 8, having a maximum impact tenacity value of 280 J/cm 2 at a test temperature of -20° C.
Claim 15
Dependent Claim
26 words
Hot strips or heavy plates according to claim 8, having a maximum impact tenacity value of 230 J/cm 2 at a test temperature of -40° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |