CA1310462C - Process and apparatus for the electromagnetic stirring of metal melts in a continuous casting chill mould - Google Patents
Process and apparatus for the electromagnetic stirring of metal melts in a continuous casting chill mouldInfo
- Publication number
- CA1310462C CA1310462C CA000566497A CA566497A CA1310462C CA 1310462 C CA1310462 C CA 1310462C CA 000566497 A CA000566497 A CA 000566497A CA 566497 A CA566497 A CA 566497A CA 1310462 C CA1310462 C CA 1310462C
- Authority
- CA
- Canada
- Prior art keywords
- continuous casting
- melt
- chill mould
- magnetic field
- mould
- 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.)
- Expired - Lifetime
Links
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
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
ABSTRACT
The invention relates to a process for the electromagnetic stirring of metal melts in a continuous casting chill mould, wherein the application of a magnetic field initiates in the melt forces which set the melt in rotation in horizontal planes. The characterizing feature of the invention is that the flow of current to the coils generating the magnetic field is alternated in a cycle such that the surface of the bath remains unmoved.
The invention relates to a process for the electromagnetic stirring of metal melts in a continuous casting chill mould, wherein the application of a magnetic field initiates in the melt forces which set the melt in rotation in horizontal planes. The characterizing feature of the invention is that the flow of current to the coils generating the magnetic field is alternated in a cycle such that the surface of the bath remains unmoved.
Description
PROCESS AND APPARATUS FOR THE ELECTROMAGNETIC STIRRING OF METAL
MELTS IN A CONTINUOUS CASTING CHILL MOULD
The invention relates to a process and apparatus for the electro-magnetic stirring of metal melts in a continuous casting chill mould, wherein a magnetic force is introduced which sets the melt in rotation in horizontal~planes. This known step is meant to prevent the formation of a dendritic structure and the formation of blowholes and segregations in the cast strand.
Electromagnetic stirring often produces in the continuous casting chill mould a strong and undesirable movement of the bath in the ~one of its surface. When casting under slag using an immersion tube. excessive movement on the bath surface can produce the following undesirable events:
- slag inclusions in the melt ~ ~
- inadequate lubrication between the strand and the chlll mould by the opening-up of the bath surface - absorption of oxygen from the atmosphere - heavy wear on the immerslon tube.
:
It is an object of the invention to provide a process and an apparatus which enable a calm bath surface to be maintained, while nevertheless intensively stirrlng the melt in the continuous casting chill mould for the purpose already mentioned in the stirring zone - i.e., the zone in which solidification starts.
Hitherto no thought was given to such a possibility, since it seemed inevitable that a rotary movement of the metal melt in the ~, . . .
.
.. ~ ;
, .
., " ' . ' .
i 1310462 chill mould causes effects which extend as far as -the zone of the bath surfacs and also turbulently mix such zone.
The invention now provides a solution to this problem which enables a calm ~ath surface to be maintained in the stirring zone in the continuous casting chill mould, even though the metal melt is intensively stirred.
To this end according to the invention the flow of current in the coil arrangement setting the melt in rotation is periodically alternated, the cycle being so selected that the surface of the bath remains unmoved. although the melt is intensively moved in the planes lying below the bath surface. The half cycle time within which the flow of current is changed is preferably adjusted to 1 to 4 seconds, with a pause of about 0.5 second between the alternation in the flow of current.
It should be pointed out that it is known to change the direction of flow in the electromagnetic stirring of the sump inside the strand guide in the continuous casting of steel slabs. For example, German AS 24 01 145 discloses such a process for avoiding secondary white bands and secondary dendrites. The cycle time after which the direction of the current is changed is 5-3~
seconds according to this citation, which discloses no steps for preventing the bath surface from movlng during stirring.
If in spite of intensively stirring the melt in the stirring zone in the continuous casting chill mould using the aforementioned means on their own, it is impossible to adjust an unmoved bath surface, according to an advanta~eous feature of the process . ~ ,, , , ~ 1 3 1 0462 according to the invention the vertical position of the coil arrangement generating the magnetic field is 60 adiu~ted in dependence on the values (field strength, frequency) characterizing the magnetic field and the paramekers influencing the rotation of the melt, more particularly the viscosity of the melt and the geometry and material of the chill mould, that the surface of the bath remains unmove~. The following practical methods are therefore used in the performance of the process according to the invention:
1. periodically changing the direction of the current, 2. periodically changing the direction of the current and that of the flow of coil current, 3. periodically changing the flow of current of the electro-magnetic field in conjunction with an adiustment of the vertical position of the arrangement of electric coils on the continuous casting chill mould.
The means stated very simply solve the problem of intensively stirring a metal melt in the stirring zone in a continuous casting chill mould, while at the same time however leaving the surface of the bath unmoved.
The drawings illustrate diagramatically an embodiment of the apparatus according to the invention for the generation of an electromagnetic field in the zone of a continuous casting chill mould, by means of which the process according to the invention can be performed. Fig. 1 is a longitudinal section and Fig. 2 a cross-section.
~` 1310~62 A coil arrangement 4 for the electromagnetic stirring of a melt 3 in a continuous casting chill mould 1 is mounted vertically adjustably in relation thereto around the continuous casting chill mould 1 into which an immersion tube 2 discharges via which the melt 3 is supplied to the continuous casting chill mould 1. The coil arrangement 4 comprises six coils 5 uniformly distributed along the periphery of the chill mould 1 around iron poles 6 having a common short-circuit ring 7 enclosed by a sheet metal iacket 8. The coil arrangement 4 is coupled to a pole reverser P
and if necessary to a frequency transducer F.
Example 1 A copper continuous casting chill mould having a wall thickness of 10 mm was enclosed by a rotary stirring coil having the following dimensions: internal diameter 515 mm, external diameter 870 mm and height 490 mm, the coil being arranged at a height of about 200 mm below the level of the molten metal in the continuous casting chill mould. The coil current was adjusted to 400 ~ and the frequency to 6 Hz. The stirring time in each direction was 3 seconds. with a pause of 0.5 second between the changes in curren-t direction.
- ~; -
MELTS IN A CONTINUOUS CASTING CHILL MOULD
The invention relates to a process and apparatus for the electro-magnetic stirring of metal melts in a continuous casting chill mould, wherein a magnetic force is introduced which sets the melt in rotation in horizontal~planes. This known step is meant to prevent the formation of a dendritic structure and the formation of blowholes and segregations in the cast strand.
Electromagnetic stirring often produces in the continuous casting chill mould a strong and undesirable movement of the bath in the ~one of its surface. When casting under slag using an immersion tube. excessive movement on the bath surface can produce the following undesirable events:
- slag inclusions in the melt ~ ~
- inadequate lubrication between the strand and the chlll mould by the opening-up of the bath surface - absorption of oxygen from the atmosphere - heavy wear on the immerslon tube.
:
It is an object of the invention to provide a process and an apparatus which enable a calm bath surface to be maintained, while nevertheless intensively stirrlng the melt in the continuous casting chill mould for the purpose already mentioned in the stirring zone - i.e., the zone in which solidification starts.
Hitherto no thought was given to such a possibility, since it seemed inevitable that a rotary movement of the metal melt in the ~, . . .
.
.. ~ ;
, .
., " ' . ' .
i 1310462 chill mould causes effects which extend as far as -the zone of the bath surfacs and also turbulently mix such zone.
The invention now provides a solution to this problem which enables a calm ~ath surface to be maintained in the stirring zone in the continuous casting chill mould, even though the metal melt is intensively stirred.
To this end according to the invention the flow of current in the coil arrangement setting the melt in rotation is periodically alternated, the cycle being so selected that the surface of the bath remains unmoved. although the melt is intensively moved in the planes lying below the bath surface. The half cycle time within which the flow of current is changed is preferably adjusted to 1 to 4 seconds, with a pause of about 0.5 second between the alternation in the flow of current.
It should be pointed out that it is known to change the direction of flow in the electromagnetic stirring of the sump inside the strand guide in the continuous casting of steel slabs. For example, German AS 24 01 145 discloses such a process for avoiding secondary white bands and secondary dendrites. The cycle time after which the direction of the current is changed is 5-3~
seconds according to this citation, which discloses no steps for preventing the bath surface from movlng during stirring.
If in spite of intensively stirring the melt in the stirring zone in the continuous casting chill mould using the aforementioned means on their own, it is impossible to adjust an unmoved bath surface, according to an advanta~eous feature of the process . ~ ,, , , ~ 1 3 1 0462 according to the invention the vertical position of the coil arrangement generating the magnetic field is 60 adiu~ted in dependence on the values (field strength, frequency) characterizing the magnetic field and the paramekers influencing the rotation of the melt, more particularly the viscosity of the melt and the geometry and material of the chill mould, that the surface of the bath remains unmove~. The following practical methods are therefore used in the performance of the process according to the invention:
1. periodically changing the direction of the current, 2. periodically changing the direction of the current and that of the flow of coil current, 3. periodically changing the flow of current of the electro-magnetic field in conjunction with an adiustment of the vertical position of the arrangement of electric coils on the continuous casting chill mould.
The means stated very simply solve the problem of intensively stirring a metal melt in the stirring zone in a continuous casting chill mould, while at the same time however leaving the surface of the bath unmoved.
The drawings illustrate diagramatically an embodiment of the apparatus according to the invention for the generation of an electromagnetic field in the zone of a continuous casting chill mould, by means of which the process according to the invention can be performed. Fig. 1 is a longitudinal section and Fig. 2 a cross-section.
~` 1310~62 A coil arrangement 4 for the electromagnetic stirring of a melt 3 in a continuous casting chill mould 1 is mounted vertically adjustably in relation thereto around the continuous casting chill mould 1 into which an immersion tube 2 discharges via which the melt 3 is supplied to the continuous casting chill mould 1. The coil arrangement 4 comprises six coils 5 uniformly distributed along the periphery of the chill mould 1 around iron poles 6 having a common short-circuit ring 7 enclosed by a sheet metal iacket 8. The coil arrangement 4 is coupled to a pole reverser P
and if necessary to a frequency transducer F.
Example 1 A copper continuous casting chill mould having a wall thickness of 10 mm was enclosed by a rotary stirring coil having the following dimensions: internal diameter 515 mm, external diameter 870 mm and height 490 mm, the coil being arranged at a height of about 200 mm below the level of the molten metal in the continuous casting chill mould. The coil current was adjusted to 400 ~ and the frequency to 6 Hz. The stirring time in each direction was 3 seconds. with a pause of 0.5 second between the changes in curren-t direction.
- ~; -
Claims (4)
1. A process for the electromagnetic stirring of metal melts in a continuous casting chill mould, wherein the application of a magnetic field initiates in the melt forces which set the melt in rotation in horizontal planes, characterized in that the flow of current to the coils generating the magnetic field is alternated in a cycle such that the surface of the bath remains unmoved.
2. A process according to claim 1, characterized in that the cycle time is adjusted to 1 to 4 seconds.
3. A process according to claim 1, characterized in that the vertical position of the coil arrangement generating the magnetic field is so adjusted in dependence on the values (field strength, frequency) characterizing the magnetic field and the parameters influencing the rotation of the melt, more particularly the viscosity of the melt and the geometry and material of the chill mould, that the surface of the bath remains unmoved.
4. An apparatus for the generation of an electromagnetic field in the zone of the continuous casting mold for the performance of the process according to claim 1, 2 or 3, characterized in that it comprises a coil arrangement which encloses the continuous casting chill mould in a horizontal plane, is mounted vertically adjustably in relation to the continuous casting mould, and has a pole reverser for changing the direction of rotation of the current, and if necessary a frequency transducer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3730300.7-24 | 1987-09-10 | ||
| DE19873730300 DE3730300A1 (en) | 1987-09-10 | 1987-09-10 | Method and apparatus for the electromagnetic stirring of metal melts in a continuous casting mould |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1310462C true CA1310462C (en) | 1992-11-24 |
Family
ID=6335633
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000566497A Expired - Lifetime CA1310462C (en) | 1987-09-10 | 1988-05-11 | Process and apparatus for the electromagnetic stirring of metal melts in a continuous casting chill mould |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS6471557A (en) |
| CA (1) | CA1310462C (en) |
| DE (1) | DE3730300A1 (en) |
| FR (1) | FR2620360A1 (en) |
| SE (1) | SE466585B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03110059A (en) * | 1989-09-22 | 1991-05-10 | Kawasaki Steel Corp | Method and apparatus for removing impurity in molten metal |
| LU87914A1 (en) † | 1991-04-03 | 1992-11-16 | Wurth Paul Sa | ELECTROMAGNETIC LINGOTINE BREWING DEVICE |
| US6443219B1 (en) | 1997-12-08 | 2002-09-03 | Nippon Steel Corporation | Method for casting molten metal |
| DE19843354C1 (en) * | 1998-09-22 | 2000-03-09 | Ald Vacuum Techn Gmbh | Apparatus for oriented solidification of a metal melt cast into a mold shell comprises guide sheets in the liquid metal cooling bath for purposes of controlling the bath flow produced by magnetic fields |
| KR100423427B1 (en) * | 1999-12-14 | 2004-03-19 | 주식회사 포스코 | Method for electro-magnetic stirring molten steel to reducing center segregation at continuous casting |
| WO2003022523A1 (en) | 2001-09-10 | 2003-03-20 | Nikon Corporation | Dressing tool, dressing device, dressing method, processing device, and semiconductor device producing method |
| DE102007037340B4 (en) | 2007-08-03 | 2010-02-25 | Forschungszentrum Dresden - Rossendorf E.V. | Method and device for the electromagnetic stirring of electrically conductive liquids |
| DE102007038281B4 (en) | 2007-08-03 | 2009-06-18 | Forschungszentrum Dresden - Rossendorf E.V. | Method and device for the electromagnetic stirring of electrically conductive liquids |
| DE102008055034A1 (en) * | 2008-12-19 | 2010-07-01 | Forschungszentrum Dresden - Rossendorf E.V. | Method and arrangement for contactless determination of velocity distributions of a liquid metal in a continuous casting mold |
| DE102010041061B4 (en) | 2010-09-20 | 2013-10-24 | Forschungsverbund Berlin E.V. | Crystallization plant and crystallization process for producing a block from a material whose melt is electrically conductive |
| RU2743437C1 (en) * | 2020-04-30 | 2021-02-18 | Общество с ограниченной ответственностью "Научно-производственный центр магнитной гидродинамики" | Device for electromagnetic mixing of liquid core of ingot in crystallizer |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT185039B (en) * | 1953-01-23 | 1956-03-26 | Boehler & Co Ag Geb | Process for casting, in particular metals |
| US3153820A (en) * | 1961-10-09 | 1964-10-27 | Charles B Criner | Apparatus for improving metal structure |
| JPS5252895Y2 (en) * | 1973-04-18 | 1977-12-01 | ||
| DE3128056C2 (en) * | 1981-07-16 | 1983-05-26 | Mannesmann AG, 4000 Düsseldorf | Process for promoting nucleation when cooling metallic melts, in particular steel melts |
-
1987
- 1987-09-10 DE DE19873730300 patent/DE3730300A1/en active Granted
-
1988
- 1988-05-11 CA CA000566497A patent/CA1310462C/en not_active Expired - Lifetime
- 1988-05-27 SE SE8801983A patent/SE466585B/en not_active IP Right Cessation
- 1988-06-08 FR FR8807617A patent/FR2620360A1/en not_active Withdrawn
- 1988-07-04 JP JP16518988A patent/JPS6471557A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6471557A (en) | 1989-03-16 |
| DE3730300A1 (en) | 1989-03-23 |
| SE466585B (en) | 1992-03-09 |
| SE8801983D0 (en) | 1988-05-27 |
| SE8801983L (en) | 1989-03-11 |
| FR2620360A1 (en) | 1989-03-17 |
| DE3730300C2 (en) | 1989-08-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |