CN1234756A

CN1234756A - Electromagnetic braking device for continuous casting mold and method of continuous casting by using same

Info

Publication number: CN1234756A
Application number: CN98801009A
Authority: CN
Inventors: 油原晋; 高田重信; 小山内寿
Original assignee: Kawasaki Steel Corp
Current assignee: JFE Steel Corp
Priority date: 1997-05-29
Filing date: 1998-05-26
Publication date: 1999-11-10
Also published as: EP0922512A1; US20020005267A1; EP0922512A4; WO1998053936A1; CA2261142A1; KR20000029610A; BR9804939A; AU716170B2; TW404866B; AU7451098A

Abstract

In a magnetic brake apparatus for a continuous casting mold having a pair of upper electromagnets which are oppositely placed near the rear faces of the opposing side walls of the continuous casting mold, and a pair of lower electromagnets which are oppositely placed thereunder, a static magnetic field being generated between each pair of electromagnets to stem the stream of the molten steel supplied to the casting mold by the static magnetic field, the apparatus has controlling units which independently control a current supplied to magnetic coils being constituents of the electromagnets. The intensity of the magnetic field between the magnetic poles of the upper and lower electromagnets can, thereby, be readily and inexpensively varied during casting without restriction.

Description

Be used to cast continuously with the electro-magnetic braking device of casting mold and with the method for continuous production of this device

The present invention relates to be used to cast continuously with the electro-magnetic braking device of casting mold and with the method for continuous production of this device, magnetostatic field takes place in the molten steel in especially relevant being suitable in the casting mold that continuous casting is used, being used to during with the control steel flow cast the electro-magnetic braking device of casting mold continuously and with the method for continuous production of this device.

Usually, steel embryo continuous casting (not shown) is performed such, and the molten steel of introducing tundish imports in the casting mold that is used to cast continuously through being connected to the immersion mouth of its bottom.In this case, the molten steel flow speed of emitting from the leakage fluid dram that immerses mouth is obvious bigger than casting speed, so field trash in the molten steel and steam bubble are invaded dearly, is sealed by scull, at this moment, makes goods produce defective inevitably.Also have, especially under the upwards mobile big situation of the jet flow of molten steel, because casting mold meniscus (モ-Le De メニスカス) portion impels fluctuating molten steel face to change, so bring harmful effect for steel billet quality and casting manipulations.

In order to solve such problem, for example open and showed a kind of continuous casting technology among the flat 3-142049 the spy, utilization applies magnetostatic field at the magnetic pole that disposes later of casting mold opposing sidewalls in the molten steel in casting mold, the copper current in the braking casting mold prevent the problems referred to above.

Fig. 6 A is the casting device major part sectional elevation of showing in the above-mentioned communique of expression; Fig. 6 B is the longitudinal section that amplify the part of Fig. 6 A.Among the figure, label 101 is continuous casting casting molds that expression is made up of relative each the pair of short edges wall 101A and Chang Bianbi (opposing sidewalls) 101B of inner water-cooled; The 102nd, in this casting mold 101, supply with the immersion mouth of molten steel from tundish (not shown); 103A, 103B are the iron core main bodys that forms magnetic circuit; 104A, 104B, 105A, 105B are connected with each iron core

main body

103A, 103B, along the upper and lower magnetic pole (iron core) of casting mold 101 widths extension.And, the 106th, be adjusted at the adjustment part, magnetic field of the static magnetic field strength that produces between each magnetic pole, this adjustment part 106 is by the bracket 107 that is fixed on support etc., be fixed on bracket 108 and the pivot pin 109 that is connected these two brackets 107,108 on the main body 103B unshakable in one's determination, with be fixed on the support, the oil pressure pump 110 that the bar front end is installed on the iron core main body constitutes.In addition, number in the figure 102B is the discharge opening that immerses mouth 102.

With in the casting mold 101,, make A upper lateral part magnetic pole 104A become the N utmost point in above-mentioned continuous casting, make B upper lateral part magnetic pole 104B become the S utmost point, in this case, produce A → B magnetic field, produce A ← B magnetic field at the bottom magnetic pole at upper magnetic pole as the left side such as at Fig. 6 A.When providing molten steel in such magnetic field, the stream that makes progress is by the top magnetic field speed reduction, and downward stream is by the bottom magnetic field speed reduction.In above-mentioned casting mold 101, under change magnetic field intensity situation between the magnetic pole of between upper magnetic pole and bottom, make oil pressure pump 110 work with adjustment part, described magnetic field 106, be that the center makes the rotation of iron core main body with pivot pin 109, the change upper magnetic pole distance between two poles from, change magnetic field intensity with this.

Yet in the disclosed technology of described communique, problem is not only essential oil pressure pump 110, pivot pin 109, but also must be used for the position-detection sensor of correct adjustable range, require expansion space for the equipment of adjusting static magnetic field strength is set, simultaneously, need many number of devices.And in described communique, also showed such method, promptly, in order to adjust magnetic field, also at the partial accession nonmagnetic substance of iron core, but in the method, problem is can not change magnetic field intensity arbitrarily according to steel grade, width and the casting speed of steel billet in casting however,, and when replacing its nonmagnetic substance, want spended time, so operating efficiency extreme difference.

In order to solve existing problem, the 1st problem of the present invention provides so a kind of technology, promptly can be easily in casting and the qurer magnetic field intensity of lower magnetic pole in the change arbitrarily.

And the 2nd purpose of the present invention is can make high-quality casting finished product by solving above-mentioned the 1st problem.

Fig. 1 is the major part cutaway view of schematic structure in the expression embodiment of the invention;

Fig. 2 is the key diagram of expression field pole combination;

Fig. 3 is a curve map of representing resulting in an embodiment strand quality;

Fig. 4 is other curve map of representing resulting in an embodiment strand quality;

Fig. 5 is the major part cutaway view of schematic structure among other embodiment of expression the present invention;

Fig. 6 is the existing casting mold schematic cross sectional views of expression;

Fig. 7 is the major part cutaway view of schematic structure among other embodiment of expression the present invention;

Fig. 8 is other key diagram of expression field pole combination;

Fig. 9 is other key diagram of expression field pole combination.

Symbol description:

10-continuous casting casting mold

12-immerses and chews

The free upper lateral part iron core of 14A-

14B-fixation side top iron core

The free upper lateral part coil of 16A-

16B-fixation side upper coil

The 17A-first top electromagnet

The 17B-second top electromagnet

The free side lower part iron core of 18A-

18B-fixation side bottom iron core

The free side lower part coil of 20A-

20B-fixation side lower coil

The 21A-first bottom electromagnet

The 21B-second bottom electromagnet

22A-linking part iron core

22B-linking part iron core

The 24A-current control device

The 24B-current control device

The 24C-current control device

The 24D-current control device

The Sm-molten steel

Describe the embodiment of the invention with reference to the accompanying drawings in detail.

Fig. 1, Fig. 7 schematically show the simple cutaway view of the continuous casting of the embodiment of the invention with the major part of the electro-magnetic braking device of casting mold.The electro-magnetic braking device of present embodiment is applicable to the continuous casting casting mold shown in the number in the figure 10.This casting mold 10 and the same thing that comes down to shown in the earlier figures 6.In its sidewall, to make the cooling water circulation, in this casting mold 10, supply with molten steel Sm from the discharge port (not shown) that immerses mouth 12.The electro-magnetic braking device of present embodiment has: the 1st top electromagnet 17A, by forming near being arranged in top iron core 14A that is provided with from the casting mold 10 sidewall back sides of immersing free side on mouth 12 discharge ports (figure left side) slightly and the top solenoid 16A that around it, reels; And the 2nd top electromagnet 17B, form by same height and position fixation side (right side among the figure) top pincers core 14B and top solenoid 16B.This a pair of the 1st, the 2nd

top electromagnet

17A, 17B make casting mold 10 be placed on therebetween configuration relatively.

In Fig. 1, below the electromagnet of top, has the 1st bottom electromagnet 21A that forms by free side lower part iron core 18A and bottom solenoid 20A; And the 2nd bottom electromagnet 21B that forms by fixation side bottom iron core 18B and bottom solenoid 20B.This a pair of

electromagnet

21A, 21B be configuration relatively similarly.And

top iron core

14A, 14B form integral body and are connected as magnetic by each connecting

portion iron core

22A, 22B respectively with bottom iron core 18A, 18B.And in the present embodiment, constituting respectively on 2 top solenoid 16A, the 16B of the 1st and the 2nd top electromagnet from top current control device 24A, and constituting respectively on 2 bottom solenoid 20A, the 20B of the 1st and the 2nd bottom electromagnet from bottom current control device 24B, supply with electric current respectively separately, want simultaneously each current value is independently controlled.

Promptly on 2

top solenoid

16A, 16B, supply with the same electric current of size arbitrarily, and on 2

bottom solenoid

20A, 20B, supply with same electric current too.Thereby the static magnetic field strength between the static magnetic field strength between 1 couple of

top electromagnet

17A, 17B and 1 couple of

bottom electromagnet

21A, 21B is respectively adjustable arbitrarily.

Then in Fig. 7, below the electromagnet of top, has the 1st bottom electromagnet 21A that forms by free side lower part iron core 18A and bottom solenoid 20A, and the 2nd bottom electromagnet 21B that forms by fixation side bottom iron core 18B and bottom solenoid 20B, the same configuration relatively of this 1 pair of electromagnet.And

top iron core

14A, 14B and

bottom iron core

18A, 18B form integral body by connecting

portion iron core

22A, 22B respectively, and do the magnetic connection.And, simultaneously, can control each current value independently from current control device 24A-24D each independent electric current of supplying with to 4

solenoid

16A, 16B, 20A, 20B.

The work of present embodiment then is described.

In Fig. 1, produce under the common magnetostatic field situation in upper and lower, utilize described 2

control device

24A, 24B, control electric current respectively independently to

top electromagnet

17A, 17B and

bottom electromagnet

21A, 21B, schematically show power-on and power-off magnet relation in Fig. 2, free upper lateral part magnetic pole is under S utmost point situation, and the upper lateral part magnetic pole that is relatively fixed is decided to be the N utmost point, free side lower part magnetic pole is decided to be the N utmost point, and fixation side bottom magnetic pole is decided to be the S utmost point.The utmost point up and down to the utmost point and homonymy that promptly clips molten steel becomes heteropole.And, in the present embodiment, being involved in the casting powder (モ-Le De パウダ-) that prevents the molten steel meniscus is purpose, for the change of molten steel face is calmed down, can strengthen the magnetic field on top, or to prevent that immersing non-metallic inclusion to the molten steel deep is purpose, braked for the molten steel in the casting mold is flowed downward, can strengthen the magnetic field of bottom.According to purpose like this,, can suitably control molten steel flow by the magnetic field intensity of any control power-on and power-off magnet.

Thereby, use the electro-magnetic braking device of present embodiment, according to width and the steel grade and the casting speed of strand, cast on one side can suitably control the static magnetic field strength of the electromagnet formation of top and bottom, improve the quality of strand with this.

Then in Fig. 7, when producing common magnetostatic field in the upper and lower, each that utilize described 4 control device 24A-24D controlled independently to each current of electromagnet, as the relation of the magnetic pole of the power-on and power-off magnet that schematically shows among Fig. 2, clip molten steel to the utmost point and homonymy up and down the utmost point become different poles.Under this situation, it is the most effective making current value to utmost point solenoid identical.And, being involved in the casting powder (モ-Le De パウダ-) that prevents the molten steel meniscus is purpose, for the change of molten steel face is calmed down, can strengthen the magnetic field on top, or to prevent that immersing non-metallic inclusion to the molten steel deep is purpose, braked for the molten steel in the casting mold is flowed downward, can be strengthened the magnetic field of bottom.

In the past, it is impossible making the magnetic field intensity forfeiture of the arbitrary part in top or bottom, even because making the current value of electromagnet coil is zero, utilize each connecting portion iron core also can do connection to last lower core, causes magnetic to connect.Yet in the present embodiment, make the sense of current counter-rotating that makes solenoid one side of electrode of opposite by described control device 24A-24D,, make relative magnetic pole homopolarity, so also can make the magnetic field intensity forfeiture as Fig. 8 and shown in Figure 9.

Thereby, for example, not only the powder of invar water surface change formation is involved in also and can guarantees subepidermal quality, prevent to capture as not make and immerse the obstruction of mouth discharge port and the bubble of the Ar gas that Xiang Gangzhong is blown into, so in the time must making the meniscus MOLTEN STEEL FLOW, the magnetic field that has between the electromagnet of top is zero effect.But according to present embodiment, control like this is also carried out easily.

Embodiment

The object lesson of present embodiment then is described.

Use has the casting mold of described Fig. 1, electro-magnetic braking device embodiment illustrated in fig. 7, casts continuously with following condition, makes the steel billet of low-carbon (LC) A1 killed steel, checks its surface and internal soundness.The bottom magnetic field intensity is fixed on 2500 Gausses, the result when Fig. 3 represents to make magnetic field intensity in upper to change, on the contrary, the result when Fig. 4 represents that magnetic field, top is fixed on 2500 Gausses.

Casting condition

Casting speed 2.5m/min

Strand width 1400mm

Slab thickness 220mm

Bottom magnetic field intensity 2000-3000 Gauss

Magnetic field intensity in upper 2000-3000 Gauss

Utilize the result of above-mentioned Fig. 3, Fig. 4 to recognize, it is very effective adjusting magnetic field intensity according to operating condition.As above detailed description, according to present embodiment, owing to can brake the steel flow in the casting mold arbitrarily, so can prevent from non-metallic inclusion to be involved in deeply by the molten steel jet flow of injecting, or casting powder is involved in the molten steel by meniscus molten steel face change, the therefore good strand of quality bills of materials efficiently.

Other embodiments of the invention then are described.

Fig. 5 is the cutaway view suitable with Fig. 1 of expression present embodiment electro-magnetic braking device schematic structure.The electro-magnetic braking device of present embodiment, there be not connecting portion iron core 22A, the 22B that is connected as magnetic with described last lower core shown in Figure 1 in any of free side and fixation side, each

iron core

14A, 14B of top, bottom, 18A, 18B all magnetic are independent, in addition, be identical with the electro-magnetic braking device of described the 1st embodiment in fact.

In the present embodiment,, the last lower core of homonymy do not connect because not making magnetic, so, though compare with the embodiment situation of above-mentioned explanation, relatively the magnetic field intensity that electric current produced that drops into is little, but can do same control, and any magnetostatic field that also can make power-on and power-off magnet simultaneously is near zero.

Though more than the present invention has been done to specify, the invention is not restricted to the content among the described embodiment, in the scope that does not break away from its main aim, can make many variations.

By above explanation,, in casting, can change the magnetic field intensity between the magnetic pole of power-on and power-off magnet easily, at an easy rate, arbitrarily according to the present invention.

Claims

1. one kind is cast continuously the electro-magnetic braking device of using casting mold, have with continuous casting approaching with the back side of the opposing sidewalls of casting mold, and be configured in therebetween the 1 pair of top electromagnet and 1 pair of bottom electromagnet of relative configuration thus relatively downwards at this casting mold, make at this each to producing magnetostatic field between the electromagnet, utilize this magnetostatic field that the steel flow of supplying with in the described casting mold is braked, it is characterized in that, such control section is set, and the electric current of independently solenoid that constitutes each electromagnet being supplied with is controlled respectively.

2. according to the device of claim 1, it is characterized in that, control section is set, control electric current of supplying with to the solenoid that constitutes 1 pair of top electromagnet and the electric current of supplying with to the solenoid that constitutes 1 pair of bottom electromagnet respectively independently.

3. according to the device of claim 1 or 2, it is characterized in that making respectively, formation is connected as magnetic with the bottom iron core near the top electromagnet of the homonymy back side configuration of the opposing sidewalls of described casting mold and the top iron core of bottom electromagnet.

4. a continuous casing uses claim 1,2 or 3 described electro-magnetic braking devices, it is characterized in that, makes from immersing the molten steel jet flow braking in the mouth discharge port supply casting mold, casts continuously.