EP0370575A1
Expired / Lapsed
EP
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Method for the manufacture of formable steel
Assignee: Tata Steel Ijmuiden BV
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Filing: 1989-11-20
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Granted: —
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Expires: 2009-11-20
Abstract
Abstract In the manufacture of formable steel in the form of a strip with a final thickness of between 0.5 and 1.5 mm, in a number of continuous successive process stages, molten steel is continuously cast into a slab of less than 100 mm thickness and the slab is rolled into the strip. To simplify the apparatus required, and improve process control, the slab is cooled down to a rolling temperature of between 300°C and a temperature T t at which at least 75% of the material is converted into ferrite, and the rolling of the slab into strip comprises at least one reduction stage with a thickness reduction of over 30%. The rolling exit speed is less than 1000 m/min. After recrystallisation, the strip is coiled.
Inventors
- 👤 Erik Bernard Ir. Van Perlstein
- 👤 Huibert Willem Dr. Ir. Den Hartog
- 👤 Robert Franciscus Gadellaa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 02:38
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0431; B; B21; B21B; B21B1/00; B21B1/46; B21B1/463; B21B1/38; B21B2001/383; B21B2201/00; B21B2201/04; C21D8/0426; C21D8/0447; C21D8/0463; C21D8/0478
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
134 words
Method for the manufacture of formable steel in the form of a strip with a final thickness of between 0.5 and 1.5 mm in which, in a number of continuous successive process stages, molten steel is continuously cast into a slab of less than 100 mm thickness and the slab is rolled into the strip, characterized in that the slab is cooled down to a rolling hot temperature of between 300°C and a temperature T t at which at least 75% of the material is converted into ferrite, in that the hot rolling of the slab into strip comprises at least one reduction stage with a thickness reduction of over 30% and has an exit speed after the hot rolling of less than 1000 m/min, and in that after recrystallisation the strip is coiled.
Claim 2
Dependent Claim
134 words
Method for the manufacture of formable steel in the form of a strip with a final thickness of between 0.5 and 1.5 mm in which, in a number of continuous successive process stages, molten steel is continuously cast into a slab of less than 100 mm thickness and the slab is rolled into the strip, characterized in that the slab is cooled down to a rolling hot temperature of between 300°C and a temperature T t at which at least 75% of the material is converted into ferrite, in that the hot rolling of the slab into strip comprises at least one reduction stage with a thickness reduction of over 30% and has an exit speed after the hot rolling of less than 1000 m/min, and in that after recrystallisation the strip is coiled.
Claim 3
Dependent Claim
19 words
Method in accordance with Claim 1, wherein the strip exit speed after the rolling is less than 750 m/min.
Claim 4
Dependent Claim
58 words
Method in accordance with Claim 1 or Claim 2, wherein the hot rolling comprises a plurality of reduction stages and is carried out partly in a temperature range in which between two successive reduction stages the steel largely recrystallises and partly in a temperature range in which between two successive reduction stages the steel substantially does not recrystallise.
Claim 5
Dependent Claim
36 words
Method in accordance with any one of Claims 1 to 3, wherein before being coiled the strip is annealed for at least 0.1 seconds at a temperature of between 600°C and 900°C to achieve said recrystallization.
Claim 6
Dependent Claim
30 words
Method in accordance with Claim 4, wherein before being coiled the strip is annealed for a period from 5 to 60 seconds at a temperature of between 700°C and 850°C.
Claim 7
Dependent Claim
22 words
Method in accordance with Claim 4 or Claim 5, wherein immediately after annealing, the strip is brought to a temperature below 450°C.
Claim 8
Dependent Claim
25 words
Method in accordance with Claim 6, wherein immediately after annealing the strip is brought to a temperature of between 450°C and 300°C and then coiled.
Claim 9
Dependent Claim
19 words
Method in accordance with Claim 6, wherein immediately after annealing the strip is brought to a temperature below 150°C.
Claim 10
Dependent Claim
19 words
Method in accordance with Claim 6, wherein immediately after annealing the strip is brought to a temperature below 80°C.
Claim 11
Dependent Claim
15 words
Method in accordance with any one of the preceding Claims, wherein the strip is pickled.
Claim 12
Dependent Claim
27 words
Method in accordance with any one of the preceding Claims, wherein after the recrystallization the strip is re-rolled with a re-rolling reduction of between 0.1% and 10%.
Claim 13
Dependent Claim
19 words
Method in accordance with any one of the preceding Claims, wherein the strip is provided with a coating layer.
Claim 14
Dependent Claim
50 words
Method in accordance with any one of the preceding Claims, wherein after the hot rolling, the strip is heated for recrystallization to a temperature of between 750°C and 850°C and then at a cooling rate of between 100°C/sec and 1000°C/sec is cooled down to a temperature of less than 450°C.
Claim 15
Dependent Claim
38 words
Method in accordance with any one of the preceding Claims, wherein before hot rolling the slab is cooled to a temperature of between 300°C and a temperature at which at least 90% of the material converts to ferrite.
Claim 16
Dependent Claim
24 words
Method in accordance with any one of the preceding Claims, wherein the slab is pre-reduced before being cooled down to the hot rolling temperature.
Claim 17
Dependent Claim
14 words
Strip manufactured by a method in accordance with any one of the preceding Claims.
References Cited (Backward Citations)
US3969162A
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EP0112027A1
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EP0194118A2
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EP0196788A2
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