JPS643591B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses molten steel in the copper wall of a mold, or unsolidified molten steel in the shell of a slab drawn from the mold, in continuous casting equipment for multiple strip casting. The present invention relates to a rotating magnetic field type electromagnetic stirring device used for stirring by electromagnetic induction.

[Prior art]

In continuous casting equipment, a stirring force is applied by electromagnetic induction to the molten steel in the copper wall of the mold or the unsolidified molten steel in the shell of the slab drawn from the mold, and the surface properties of the slab are improved by floating inclusions. It is known that it has great effects on continuous casting of undeoxidized steel by floating air bubbles in the surface layer of the slab, and on improving the internal quality of the slab by improving the equiaxed crystal structure of the slab and reducing center segregation. Yes (Reference [Continuous Casting in a Rotating Magnetic Field (published by Nippon-Soviet Press)]).

In continuous casting equipment for multi-strip casting, a pair of linear inductors are installed above and below the slab so as to sandwich the two strands, and generate magnetic fields traveling in opposite directions. It is also known that an electromagnetic stirring device was devised to provide rotational force to the continuous casting, and was installed in the secondary cooling zone of continuous casting (Japanese Patent Laid-Open No. 57-209757).
issue).

[Problem that the invention seeks to solve]

However, when stirring molten steel within the copper walls of a mold, sufficient thrust cannot be obtained with conventional linear inductors due to the attenuation of the magnetic field by the copper walls, the small width of the slab, and the small effective thrust. Nakatsuta.
In addition, in the conventional salient pole rotating magnetic field type or concentric winding rotating magnetic field type, the inductor is relatively large and the spacing between the multi-strip slabs is restricted. It was impossible to stir at the same location at the same time.

The present invention provides an inductor in the shape of a spectacle, or in the form of two or more ports arranged in a row, for unsolidified molten steel in the copper wall of a multi-strip mold or in the shell of a slab drawn from the mold. By winding each side of the iron core, generating a rotating magnetic field in each multi-strip slab, and selecting an appropriate cooling method, we can create a high-thrust, compact, multi-strip continuous casting equipment. The present invention provides an electromagnetic stirring device for use in.

[Means for solving problems]

The electromagnetic stirring device of the present invention is driven by two-phase alternating current with a phase difference of about 90 degrees from each other, and in order to generate a rotating magnetic field inside the multi-strand strand, there are two or more inductors inside the inductor. , consists of an inductor core in the shape of a spectacles or two or more openings lined up in a row so as to have a slab passage, and windings on each side of the inductor core, and located between each opening. The side induction cores and their windings are shared.
The features of the present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. This is 2
This is used for continuous strip casting equipment.

The inductor core 1, which is laminated with glasses-shaped magnetic material and has two openings, is wound around each side of the inductor core 1 so that two strips of slab can pass therethrough. Seven windings 2 to 8 surround the
is wound around the inductor core 1. The winding 5 wound around the side sandwiched between the two slabs is used in common to excite the slabs passing through each of the two openings.

Therefore, an AC power source of the same phase is connected to the windings 3, 5, and 7 with the same polarity, and the other paired windings 2, 4 and windings 6, 8 are connected to each other from the phase of the AC power source. Connect an AC power supply with a 90° phase delay.
By doing this, the main flux in the inductor core 1 is minimized, the cross-sectional area of the core 1 is minimized, and a two-phase, two-pole rotating magnetic field is simultaneously generated in the two slabs, and the inside of the slab is of molten steel is stirred.

The winding conductor shall have a shape compatible with the cooling method. In the case of indirect cooling by immersion cooling, use a solid conductor with water-resistant insulation on the outside, and in the case of direct cooling by internal water passage, use a hollow conductor, and use a combination of direct and indirect cooling to improve cooling capacity. In the case of combined cooling with large current and high thrust type, use a hollow type with water-resistant insulation on the outside. FIG. 2 shows the cooling water passage 3'
A winding wire with .

FIG. 2 shows a longitudinal cross-sectional view of the iron core 1. winding 5,
a mouth surrounded by 6, 7 and 8, and a winding 2,
A mold copper plate 12 is located in each of the openings surrounded by 3, 4, and 5, and the space inside this mold copper plate 12 is a slab passage section 13. The phase of the AC power supply is π/
2, the magnetic fields generated by windings 6, 8 and 4, 2 are maximum, and the magnetic fields generated by windings 7, 5, and 3 are minimum,
When the phase of the AC power supply is π/2, the magnetic field generated by windings 6, 8 and 4, 2 is the minimum, and the magnetic field generated by windings 7, 5, and 3 is maximum, and the magnetic field is surrounded by windings 5, 6, 7, and 8. The aperture surrounded by windings 2, 3, 4 and 5 generates a rotating magnetic field in the directions indicated by arrows A and B in FIG. 3, respectively.

FIG. 4 shows another embodiment of the invention.
This embodiment is constructed for three threads, and the iron core 1 has three ports formed therein and a winding wire wound around each side. There are 10 windings. Similar to the embodiment shown in FIG.
5, 6, 7 and 9, π/
An alternating current voltage with two phases delayed is applied. winding 8,
The opening surrounded by 7, 10 and 9 produces a rotating magnetic field in the direction indicated by arrow A in FIG. Winding 1
The opening surrounded by 0, 6, 11 and 2 produces a rotating magnetic field in the direction shown by arrow B in FIG. Furthermore, a rotating magnetic field in the direction indicated by arrow C in FIG. 5 is generated at the opening surrounded by windings 11, 5, 4, and 3.

〔Effect of the invention〕

The electromagnetic stirring device in the continuous casting equipment for multi-strip casting according to the present invention has an inductor core shaped like a spectacle, or two or more openings arranged in a line so that the inductor core has a plurality of openings through which the cast sides of the multi-strips pass. By connecting two phases of alternating current with a phase difference of approximately 90 degrees to the coils incorporated in each side of the coil, so as to generate a rotating magnetic field within each cast-side passing portion, The inductor in the part sandwiched between the slabs can be shared by both parties, and the inductor can be made smaller, making it possible to shorten the interval between slab streams and efficiently stirring the slabs. did.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention;
The appearance of the row inductor is shown. FIG. 2 is a sectional view of the inductor shown in FIG. 1, and FIG. 3 is a sectional view of the iron core showing the direction of current in the coil, the direction of the main magnetic flux, and the direction of the rotating magnetic field. FIG. 4 is a perspective view showing another embodiment of the present invention, showing the appearance of a three-strip inductor. FIG. 5 shows a sectional view of the core of the inductor shown in FIG. 4. 1...Laminated inductor core, 2-11...Coil, 3'...Cooling water passage, 12...Mold copper plate,
13... Slab passage section.

Claims (1)

[Claims] 1. In an inductor for stirring the unsolidified molten steel of a slab in a continuous casting device having two or more slab passages, the inductor core is shaped like a spectacle or two or more holes are arranged in a row. Electromagnetic stirring in continuous casting equipment, characterized in that the cores are arranged side by side, windings are applied to each side, and the induction core and the windings on the side located between each mouth are shared. Device.