Patent EP0306076A1 successfully refreshed from Google Patents.
EP0306076A1
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Method and apparatus for the manufacture of formable steel strip
Assignee: Tata Steel Ijmuiden BV
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Filing: 1988-08-19
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Granted: —
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Expires: 2008-08-19
Abstract
Abstract In the manufacture of formable steel strip having a thickness between 0.5 and 1.5 mm, the following process steps are performed sequentially in a continuous process: (a) in a continuous casting machine (1,2), forming liquid steel into a hot slab having a thickness of less than 100 mm, (b) hot rolling (8,9) the hot slab from step (a), in the austenitic region and below 1100°C, to form strip having a thickness of between 2 and 5 mm, (c) cooling (11) the strip from step (b) to a temperature between 300°C and the temperature T t at which 75% of the steel is converted to ferrite, (d) rolling (12) the cooled strip from step (c) at said temperature between 300°C and T t with a thickness reduction of at least 25% at a rolling speed not more than 1000 m/min., (e) coiling the rolled strip from step (d).
Inventors
- 👤 Huibert Willem Dr. Ir. Den Hartog
- 👤 Erik Bernard Van Perlstein
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 18:17
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0431; B; B21; B21B; B21B1/00; B21B1/46; B21B1/463; B21B13/00; B21B13/18; B21B13/20; B21B2201/00; B21B2201/04
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
147 words
Method for the manufacture of formable steel strip having a thickness between 0.5 and 1.5 mm characterised by the following process steps which are performed sequentially in a continuous process: (a) in a continuous casting machine forming liquid steel into a hot slab having a thickness of less than 100 mm, (b) hot rolling the hot slab from step (a), in the austenitic region and below 1100°C, to form strip having a thickness of between 2 and 5 mm, (c) cooling the strip from step (b) to a temperature between 300°C and the temperature T t at which 75% of the steel is converted to ferrite, (d) rolling the cooled strip from step (c) at said temperature between 300°C and T t with a thickness reduction of at least 25% at a rolling speed not more than 1000 m/min., (e) coiling the rolled strip from step (d).
Claim 2
Dependent Claim
147 words
Method for the manufacture of formable steel strip having a thickness between 0.5 and 1.5 mm characterised by the following process steps which are performed sequentially in a continuous process: (a) in a continuous casting machine forming liquid steel into a hot slab having a thickness of less than 100 mm, (b) hot rolling the hot slab from step (a), in the austenitic region and below 1100°C, to form strip having a thickness of between 2 and 5 mm, (c) cooling the strip from step (b) to a temperature between 300°C and the temperature T t at which 75% of the steel is converted to ferrite, (d) rolling the cooled strip from step (c) at said temperature between 300°C and T t with a thickness reduction of at least 25% at a rolling speed not more than 1000 m/min., (e) coiling the rolled strip from step (d).
Claim 3
Dependent Claim
31 words
Method according to claim 1 further including the step (f) subjecting the rolled strip from step (d), before step (e), to recrystallizing annealing at above 620°C for at least 0.1 second.
Claim 4
Dependent Claim
25 words
Method according to claim 2 wherein said recrystallizing annealing is at a temperature between 700 and 850°C for a period of 5 to 60 seconds.
Claim 5
Dependent Claim
23 words
Method according to claim 2 or claim 3 wherein in step (d) the strip has a temperature in the range 400 to 600°C.
Claim 6
Dependent Claim
30 words
Method according to claim 1 wherein in step (d) the strip has a temperature in the range 650°C to T t , and no reheating for recrystallizing annealing takes place.
Claim 7
Dependent Claim
34 words
Method according to any one of claims 1 to 5 further including the step (g) overaging the rolled strip from step (d) at a temperature between 300 and 450°C (after step (f) if performed).
Claim 8
Dependent Claim
27 words
Method according to claim 6 wherein step (e) (coiling) is at a temperature between 300 and 450°C and said overaging of step (g) takes place after coiling.
Claim 9
Dependent Claim
23 words
Method according to any one of claims 1 to 6 wherein before step (e) (coiling) the rolled strip is cooled to below 80°C.
Claim 10
Dependent Claim
21 words
Method according to claim 8 wherein the strip is subjected to pickling after the cooling to below 80°C and before coiling.
Claim 11
Dependent Claim
33 words
Method according to claim 8 or claim 9 wherein after the cooling to below 80°C, and after the pickling is performed, the strip is temper rolled with a reduction of 0.2 to 10%.
Claim 12
Dependent Claim
23 words
Method according to any one of claims 1 to 10 wherein the rolling speed in step (d) is not more than 700 m/min.
Claim 13
Dependent Claim
30 words
Method according to any one of claim 1 to 11 wherein step (d) is performed at a temperature at which at least 90% of the steel is converted into ferrite.
Claim 14
Dependent Claim
50 words
Method according to any one of claims 1 to 12 wherein step (b) takes place in two stages, of which the first stage is a main reduction in a planetary mill stand and the second stage is a thickness reduction of not more than 40% in a further mill stand.
Claim 15
Dependent Claim
21 words
Method according to claim 13 wherein the thickness reduction in said further mill stand is in the range 10 to 20%.
Claim 16
Dependent Claim
35 words
Method according to any one of claims 1 to 14 wherein between steps (a) and (b) the slab passes through a homogenizing furnace which is held at a temperature in the range 850 to 1100°C.
Claim 17
Dependent Claim
30 words
Method according to any one of claims 1 to 15 wherein, after at least one of steps (a) and (b), oxide skin on the surface of the steel is removed.
Claim 18
Dependent Claim
146 words
Apparatus for carrying out the method of claim 1, having the following items arranged in the sequence below so as to perform a continuous process: (i) at least one continuous casting machine for forming liquid steel into slabs having a thickness of 30 to 100 mm, (ii) a homogenizing furnace for the slab from (i), (iii) a planetary mill followed by a planishing mill stand for hot rolling of the slab from (ii) into strip, (iv) means for cooling the strip from (iii) to a temperature in the range 300 to 850°C and homogenizing the strip at that temperature, (v) at least one four-high mill stand for rolling the strip from (iv), (vi) a furnace for recrystallization- annealing of the strip from (v) at a temperature of at least 620°C, (vii) cooling means for cooling the strip from (vi), and (viii) at least one strip coiler.
Claim 19
Dependent Claim
28 words
Apparatus according to claim 17 further having: (vii-a) a homogenization furnace for homogenizing the strip from (vii) for overaging at a temperature in the range 300 to 450°C.
Claim 20
Dependent Claim
57 words
Apparatus according to claim 17 or claim 18 further having, after (vii) and after (vii-a) if provided (vii-b) before (ix), cooling means for cooling the strip to below 80°C, (vii-c) between (vii-b) and (ix), pickling means for pickling the strip from (vii-b) (vii-d) between (vii-c) and (ix), a four-high temper mill stand for the strip from (vii-c).
References Cited (Backward Citations)
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