EP1018382A1 - Method and device for continuous casting - Google Patents
Method and device for continuous casting Download PDFInfo
- Publication number
- EP1018382A1 EP1018382A1 EP99922589A EP99922589A EP1018382A1 EP 1018382 A1 EP1018382 A1 EP 1018382A1 EP 99922589 A EP99922589 A EP 99922589A EP 99922589 A EP99922589 A EP 99922589A EP 1018382 A1 EP1018382 A1 EP 1018382A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- rolling
- cast strip
- rollers
- mold
- unsolidified
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
Definitions
- the present invention relates to a continuous casting method and a continuous casting device.
- a thin cast strip produced by a continuous casting device is rolled thinner into a steel sheet by rolling mills in the downstream. If a cast strip is made thin enough in the casting process, the downstream rolling process can be made short, which reduces the cost of the rolling equipment.
- the object of the present invention is to provide a continuous casting method and a continuous casting device for producing such thin cast strips.
- a narrow aperture is made in the mold.
- the molding aperture cannot be made as narrow as it is desired to be because of the thickness of the nozzle of melted steel.
- a molding aperture of even width through its length, or depth, can be made as narrow as 90 mm. If the aperture is made narrower than 90 mm, stable casting cannot be made. Accordingly, some molds have an aperture which is wide at its inlet and narrows, towards its outlet, to 50 to 120 mm.
- the reduction per roller has to be 10 mm or less, and the rolling-completion point has to be 1,900 mm or more below the surface of melted steel in the mold. Under such restrictions, it has, as a matter of fact, been impossible to complete the rolling of a cast strip before its solidified shell grows thick. Accordingly, a method of producing thin enough cast strips continuously has not been made available yet.
- the object of the present invention is to provide a continuous casting method and a continuous casting device for producing cast strips which are thinner, and whose quality is higher, than those produced by the conventional unsolidified rolling method.
- a continuous casting method of producing cast strips of thickness of 40 mm or less in a continuous casting device comprises (i) the step of rolling a cast strip, which is 50 to 120 mm in thickness at the outlet of a mold, in an unsolidified state that its solidified shell has grown to a certain thickness and melted steel is flowing in its central portion and (ii) the step of rolling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
- a continuous casting device which comprises (i) a non-rolling area 400 to 1,000 mm long which is disposed immediately below a mold, the mold having an aperture which is 50 to 120 mm wide at its outlet, (ii) a group of rollers for rolling a cast strip in an unsolidified state, the group of rollers being provided in the downstream of the non-rolling area, and (iii) a group of rollers for rolling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
- the numeral 1 indicates a mold; 2, support rollers in a non-rolling area 2A; 3, rolling rollers in an unsolidified rolling area 3A; and 4, rolling rollers in a semisolidified rolling area 4A.
- the two faces of the aperture of the mold 1, corresponding to the two faces of a cast strip A, may be parallel with each other, or may be tilted to each other so as to make the outlet narrower than the inlet.
- the outlet of the aperture is 50 to 120 mm wide.
- the spacing between the two faces of the aperture is 50 to 120 mm at the outlet.
- the non-rolling area 2A is directly under the mold 1 and have a length of 400 to 1,000 mm.
- the cast strip A is guided by the support rollers 2 but not rolled in the non-rolling area 2A.
- the melted steel poured into the mold 1 is cooled in it, and a solidified shell S is formed around the melted steel, or cast strip A. Then, its solidification is promoted by water spray, etc. in the non-rolling area 2A.
- the rollers 3 roll the cast strip A in an unsolidified state.
- melted steel is flowing in the central portion of the cast strip A and, therefore, the cast strip A can be rolled by small pressure. Because the required rolling pressure is small, rollers 3 of a small diameter can be disposed with small spacing between them and, hence, the cast strip A is less liable to develop bulging due to the static pressure in the melted steel.
- rollers 3 are rolling the cast strip A to reduce its thickness in the unsolidified rolling area 3A, the cast strip A cools naturally, thickening its shell S.
- the two face (as distinguished from “side") portions of the shell S of the cast strip A meet each other at a point 6 on the bottom of the unsolidified rolling area 3A, where the cast strip A completes its solidification.
- the cast strip A has no melted steel flowing in its central portion but has not completely solidified yet.
- the mean temperature of a section (the ?????? section) of the cast strip A is over 1,200o C, or the temperature of the center of the cast strip A is over 1,350o-1,400o C, and the mean temperature of its solidified shell S is 1,250o to 1,300o C. It has been found by the inventor(s) that a cast strip A in such a semisolidified state can be rolled with a pressure far smaller than the reaction which occurs in the cast strip A if it is rolled in a solidified state.
- the mean temperature of the solidified shell of a cast strip in the solidified rolling area, where the cast strip is rolled in a solidified state, of the prior art II is about 1,100o C, and the deformation resistance is 4 kg/mm 2 .
- the deformation resistance in the semisolidified rolling area 4A in accordance with the present invention is 1 kg/mm 2 or less because the mean temperature of the solidified shell in the area is 1,250o to 1,300o C.
- the deformation resistance is reduced to a quarter.
- rollers 4 of a diameter as small as that of the rollers 3 in the unsolidified rolling area 3A can be used in the semisolidified area 4A and, hence, the rollers 4 can be disposed with small spacing between them. Therefore, the freshly formed solidified shell does not bulge. Besides, the cast strip A does not develop cracks in it because it is rolled in a high temperature area where a rolling temperature (1,100oC or more) above the embrittlement temperature range can be secured.
- rolling segments Used in the unsolidified and semisolidified rolling areas 3A and 4A are rolling segments each comprising small-diameter rollers which are disposed with small spacing between them.
- the rolling segments are so configured that they can be raised and lowered, and tilted.
- the thickness of the cast strip A after the rolling in the unsolidified and semisolidified rolling areas 3A and 4A can freely be set by changing the magnitudes of up-and-down movement and tilting movement of the rolling segments.
- the solidification-completing point 6 moves up and down, which causes the length of the unsolidified rolling area 3A and the semisolidified rolling area 4A to change.
- the deformation resistance in the cast strip A in the semisolidified rolling area 4A does not rise suddenly, a prescribed thickness of the cast strip A can be secured notwithstanding such fluctuations.
- Fig. 1 Although the continuous casting device shown in Fig. 1 is a vertical type, it can also be a curved type with the same mechanism.
- cast strips can be rolled thinner than those by the conventional unsolidified rolling method. Besides, cast strips of better quality can be produced continuously.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Metal Rolling (AREA)
Abstract
A continuous casting device comprising (i) a non-rolling
area 400 to 1,000 mm long which is disposed immediately below
a mold, the mold having an aperture which is 50 to 120 mm wide
at its outlet, (ii) a group of rollers for rolling a cast strip
in an unsolidified state, the group of rollers being provided
in the downstream of the non-rolling area, and (iii) a group
of rollers for rolling the cast strip further in a
semisolidified state that there is no flow of melted steel
in its central portion but it has not completely solidified
yet. The cast strip, which is 50 to 120 mm in thickness at
the outlet of the mold, is rolled in the unsolidified state
and further rolled in the semisolidified state to be reduced
to thickness of 40 mm or less. Cast strips can be rolled thinner
than those by the conventional unsolidified rolling method.
Besides, better quality of cast strips is attained.
Description
- The present invention relates to a continuous casting method and a continuous casting device. A thin cast strip produced by a continuous casting device is rolled thinner into a steel sheet by rolling mills in the downstream. If a cast strip is made thin enough in the casting process, the downstream rolling process can be made short, which reduces the cost of the rolling equipment. The object of the present invention is to provide a continuous casting method and a continuous casting device for producing such thin cast strips.
- To produce thin cast strips, a narrow aperture is made in the mold. However, the molding aperture cannot be made as narrow as it is desired to be because of the thickness of the nozzle of melted steel. A molding aperture of even width through its length, or depth, can be made as narrow as 90 mm. If the aperture is made narrower than 90 mm, stable casting cannot be made. Accordingly, some molds have an aperture which is wide at its inlet and narrows, towards its outlet, to 50 to 120 mm.
- To make a cast strip thinner than the outlet of the aperture of a mold, the unsolidified rolling method has been used, whereby a strip drawn out of the mold and having flowing melted steel inside is rolled (prior art I).
- However, because the rolling of a cast strip by the unsolidified rolling method has to be completed before the two face (as distinguished from "side") portions of its solidified shell meet each other, the cast strip cannot be made thinner than the total thickness of the two face portions of its solidified shell in the rolling area. If the rolling of a cast strip is started immediately below the mold to complete the rolling before the shell grows thick and thereby attain a thin cast strip, rolling the cast strip immediately below the mold disturbs the contact between the cooling plates of the mold and the solidified shell, causing uneven solidification, which in turn causes a breakout or surface cracks. If the reduction per roller is made large to raise the rolling-completion point upstream, inner cracks occur. Accordingly, the reduction per roller has to be 10 mm or less, and the rolling-completion point has to be 1,900 mm or more below the surface of melted steel in the mold. Under such restrictions, it has, as a matter of fact, been impossible to complete the rolling of a cast strip before its solidified shell grows thick. Accordingly, a method of producing thin enough cast strips continuously has not been made available yet.
- On the other hand, disclosed in the Japanese Unexamined Patent Application No. 164460/H8 (1996) is a method by which a cast strip is rolled with rollers of a large diameter only after the completion of its solidification. In its unsolidified area, the cast strip is not rolled, but just guided by guide rollers (prior art II).
- Because even small reduction of a completely solidified cast strip requires a large pressure and rollers of a large diameter, the device materializing the above method becomes large and costly. Besides, cast strips by the method are liable to develop troubles, which reduces their quality. For example, cracks can occur in such a cast strip due to the decrease in temperature of its corners while it is being rolled.
- In accordance with the above, the object of the present invention is to provide a continuous casting method and a continuous casting device for producing cast strips which are thinner, and whose quality is higher, than those produced by the conventional unsolidified rolling method.
- In accordance with the first invention, there is provided a continuous casting method of producing cast strips of thickness of 40 mm or less in a continuous casting device. The method comprises (i) the step of rolling a cast strip, which is 50 to 120 mm in thickness at the outlet of a mold, in an unsolidified state that its solidified shell has grown to a certain thickness and melted steel is flowing in its central portion and (ii) the step of rolling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
- In accordance with the second invention, there is provided a continuous casting device, which comprises (i) a non-rolling area 400 to 1,000 mm long which is disposed immediately below a mold, the mold having an aperture which is 50 to 120 mm wide at its outlet, (ii) a group of rollers for rolling a cast strip in an unsolidified state, the group of rollers being provided in the downstream of the non-rolling area, and (iii) a group of rollers for rolling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
-
- Fig. 1 shows the general arrangement of the mold and rollers of an embodiment of continuous casting device of the present invention.
- Fig. 2 is a graph showing the relation between the temperature of a cast strip and its deformation resistance.
-
- In Fig. 1, the
numeral 1 indicates a mold; 2, support rollers in anon-rolling area 2A; 3, rolling rollers in an unsolidifiedrolling area 3A; and 4, rolling rollers in a semisolidifiedrolling area 4A. - The two faces of the aperture of the
mold 1, corresponding to the two faces of a cast strip A, may be parallel with each other, or may be tilted to each other so as to make the outlet narrower than the inlet. In either case, the outlet of the aperture is 50 to 120 mm wide. In other words, the spacing between the two faces of the aperture is 50 to 120 mm at the outlet. - The
non-rolling area 2A is directly under themold 1 and have a length of 400 to 1,000 mm. The cast strip A is guided by thesupport rollers 2 but not rolled in thenon-rolling area 2A. - The melted steel poured into the
mold 1 is cooled in it, and a solidified shell S is formed around the melted steel, or cast strip A. Then, its solidification is promoted by water spray, etc. in thenon-rolling area 2A. - In the unsolidified
rolling area 3A below thenon-rolling area 2A, therollers 3 roll the cast strip A in an unsolidified state. In the unsolidified state, melted steel is flowing in the central portion of the cast strip A and, therefore, the cast strip A can be rolled by small pressure. Because the required rolling pressure is small,rollers 3 of a small diameter can be disposed with small spacing between them and, hence, the cast strip A is less liable to develop bulging due to the static pressure in the melted steel. - While the
rollers 3 are rolling the cast strip A to reduce its thickness in the unsolidifiedrolling area 3A, the cast strip A cools naturally, thickening its shell S. - The two face (as distinguished from "side") portions of the shell S of the cast strip A meet each other at a
point 6 on the bottom of the unsolidifiedrolling area 3A, where the cast strip A completes its solidification. - In the semisolidified
rolling area 4A under the solidification-completingpoint 6, the cast strip A has no melted steel flowing in its central portion but has not completely solidified yet. In the semisolidifiedrolling area 4A, the mean temperature of a section (the ?????? section) of the cast strip A is over 1,200º C, or the temperature of the center of the cast strip A is over 1,350º-1,400º C, and the mean temperature of its solidified shell S is 1,250º to 1,300º C. It has been found by the inventor(s) that a cast strip A in such a semisolidified state can be rolled with a pressure far smaller than the reaction which occurs in the cast strip A if it is rolled in a solidified state. - As shown in Fig. 2, the mean temperature of the solidified shell of a cast strip in the solidified rolling area, where the cast strip is rolled in a solidified state, of the prior art II is about 1,100º C, and the deformation resistance is 4 kg/mm2. On the other hand, the deformation resistance in the semisolidified
rolling area 4A in accordance with the present invention is 1 kg/mm2 or less because the mean temperature of the solidified shell in the area is 1,250º to 1,300º C. Thus, in accordance with the present invention, the deformation resistance is reduced to a quarter. - Accordingly,
rollers 4 of a diameter as small as that of therollers 3 in the unsolidifiedrolling area 3A can be used in thesemisolidified area 4A and, hence, therollers 4 can be disposed with small spacing between them. Therefore, the freshly formed solidified shell does not bulge. Besides, the cast strip A does not develop cracks in it because it is rolled in a high temperature area where a rolling temperature (1,100ºC or more) above the embrittlement temperature range can be secured. - Used in the unsolidified and semisolidified
rolling areas rolling areas - On the other hand, due to fluctuations in the casting speed, the solidification-completing
point 6 moves up and down, which causes the length of the unsolidifiedrolling area 3A and the semisolidifiedrolling area 4A to change. However, because the deformation resistance in the cast strip A in the semisolidifiedrolling area 4A does not rise suddenly, a prescribed thickness of the cast strip A can be secured notwithstanding such fluctuations. - Although the continuous casting device shown in Fig. 1 is a vertical type, it can also be a curved type with the same mechanism.
- In accordance with the present invention, cast strips can be rolled thinner than those by the conventional unsolidified rolling method. Besides, cast strips of better quality can be produced continuously.
Claims (2)
- A continuous casting method of producing cast strips of thickness of 40 mm or less in a continuous casting device, comprising the steps of:rolling a cast strip, which is 50 to 120 mm in thickness at the outlet of a mold, in an unsolidified state that its solidified shell has grown to a certain thickness and melted steel is flowing in its central portion; androlling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
- A continuous casting device comprising:a non-rolling area 400 to 1,000 mm long which is disposed immediately below a mold, the mold having an aperture which is 50 to 120 mm wide at its outlet;a group of rollers for rolling a cast strip in an unsolidified state, the group of rollers being provided in the downstream of the non-rolling area; anda group of rollers for rolling the cast strip further in a semisolidified state that there is no flow of melted steel in its central portion but it has not completely solidified yet.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15718798 | 1998-06-05 | ||
JP15718798A JP3314036B2 (en) | 1998-06-05 | 1998-06-05 | Continuous casting method and continuous casting device |
PCT/JP1999/002879 WO1999064189A1 (en) | 1998-06-05 | 1999-05-28 | Method and device for continuous casting |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1018382A1 true EP1018382A1 (en) | 2000-07-12 |
Family
ID=15644108
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99922589A Withdrawn EP1018382A1 (en) | 1998-06-05 | 1999-05-28 | Method and device for continuous casting |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1018382A1 (en) |
JP (1) | JP3314036B2 (en) |
WO (1) | WO1999064189A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008046507A1 (en) * | 2006-10-13 | 2008-04-24 | Sms Demag Ag | Strand guiding device and method of operating it |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT201800006563A1 (en) * | 2018-06-21 | 2019-12-21 | PLANT AND PROCEDURE FOR THE PRODUCTION OF A HOT ROLLED METAL TAPE |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6082257A (en) * | 1983-10-07 | 1985-05-10 | Kawasaki Steel Corp | Continuous forging method in continuous casting |
JPH0215858A (en) * | 1988-07-02 | 1990-01-19 | Sumitomo Metal Ind Ltd | Method and device for continuously casting cast strip |
JPH03114643A (en) * | 1990-06-02 | 1991-05-15 | Nippon Steel Corp | Continuous casting method |
JPH0890166A (en) * | 1994-09-21 | 1996-04-09 | Sumitomo Metal Ind Ltd | Continuous casting apparatus and method therefor |
-
1998
- 1998-06-05 JP JP15718798A patent/JP3314036B2/en not_active Expired - Lifetime
-
1999
- 1999-05-28 EP EP99922589A patent/EP1018382A1/en not_active Withdrawn
- 1999-05-28 WO PCT/JP1999/002879 patent/WO1999064189A1/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO9964189A1 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008046507A1 (en) * | 2006-10-13 | 2008-04-24 | Sms Demag Ag | Strand guiding device and method of operating it |
US8162033B2 (en) | 2006-10-13 | 2012-04-24 | Sms Demag Aktiengesellschaft | Strand guiding device and method of operating it |
Also Published As
Publication number | Publication date |
---|---|
WO1999064189A1 (en) | 1999-12-16 |
JP3314036B2 (en) | 2002-08-12 |
JPH11347700A (en) | 1999-12-21 |
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Legal Events
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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17P | Request for examination filed |
Effective date: 20000203 |
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AK | Designated contracting states |
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Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20021203 |