JPS5924900B2 - Continuous and semi-continuous metal casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuous and semi-continuous casting of ferrous and non-ferrous metals and their alloys while forming ingots in a magnetic field.

British Patent No. 1,157,977 discloses an apparatus for continuous and semi-continuous casting of metals, which includes an annular inductor which acts on the molten metal and forms it into an ingot by means of an electromagnetic field, which imparts the required axial distribution to the magnetic field. and an annular cooling means to uniformly supply a cooling medium to the surface of the ingot being formed.

The inductor consists of one turn of a steel tube with a rectangular cross section.

Coolant busbars are connected to the inductor, insulated from each other by a dielectric liner.

However, when such an inductor is activated, the magnetic field at the inductor connection to the power supply bus becomes noticeably weaker.

As a result, the ingot is deformed, its circular shape distorted, and it bulges out along its surface.

The aim of the invention is to eliminate this drawback.

The present invention contemplates designing continuous and semi-continuous casting equipment for metals so that the cross-sectional area of the ingot is strictly circular to improve the surface quality of the ingot during casting.

To achieve the above and other objects, an annular inductor connected to a power supply, an annular magnetic field shield disposed within the annular hollow inductor, and an annular magnetic field shield disposed outside the inductor. In continuous and semi-continuous casting equipment for metals comprising annular cooling means, inductor pieces are formed as insert pieces of high resistance metal such as steel on both sides of the inductor contacts in contact with the power supply busbar, and the inductor together with the side wall of the annular inductor to form a hollow part of the annular inductor, and the inductor pieces are box-shaped and each length is at least three times longer than the thickness of the inductor piece, and An arrangement is provided in which the vertical wall of the box is connected to the dielectric lateral wall facing the ingot being formed.

Because a material with a higher specific electrical resistance than that of the inductor is used for the insert piece, current flows from the bus bar along the inductor sidewall facing the ingot during casting, and virtually no current passes through the insert piece. G).

The current is then concentrated at the busbar connection point, creating a uniform electromagnetic field that acts on the molten metal all around the circumference of the ingot.

As a result, the circular shape of the ingot is not distorted because the magnetic field does not weaken at the connection point of the power supply bus.

The quality of the ingot was also improved because the dimensions of the insert and its shape ratios were found to eliminate surface defects and circular cross-sectional distortions.

Embodiments of the present invention will be described below with reference to the drawings.

The annular cooling means 3 of the continuous and semi-continuous casting machine for metals are provided with cavities 4 and 5 for the passage of a liquid cooling medium (water), and all cooling means are connected to the support 1 (no. (Fig. 1).

Each of the cavities communicates with a through duct in order to drain the cooling medium onto the surface of the ingot 7 during casting.

At the bottom, a circular orifice 8 of the annular cooling means 3 accommodates a base plate, not shown.

An annular inductor 9 (FIG. 2) made of a steel pipe with a rectangular cross section is fixed to the inner wall of the annular cooling means 3.

Power supply busbars 10 are connected to the inductor 9, separated from each other by liners 11 of electrically insulating material.

The inductor provides a magnetic field that holds the molten metal in columns as it solidifies into an ingot.

The areas on both sides of the connection of the inductor 10 with the power supply busbar are designed as insert pieces 12 of high resistance steel.

40 to 6 from the specific electrical resistance of the copper used to make the annular inductor.
The insert piece may be made of a material other than stainless steel if the 0x specific electrical resistance is high.

The length l of the insert piece 12 is three times or more thicker than the thickness a of the inductor 9.

The insert piece 12 (FIG. 3) is box-shaped, with its longitudinal walls connected to the solid side wall 13 of the inductor 9 facing the ingot being cast.

Furthermore, the end of the box-shaped member is connected to one side of the corresponding wall of the hollow inductor 9, and on the opposite side the end of the box-shaped member is connected to a hollow conductive busbar.

The insert piece also forms an encircling cavity 14 with the inductor wall to allow cooling medium to flow into the cavity.

A cavity 15 of the power supply bus 10 communicates with this cavity.

An electromagnetic shield 16 is located at the top of the circular hole of the annular inductor 9.

When the inductor surrounds the ingot, an insert piece 12 is placed on the outside of the side wall of the inductor 9, and when the ingot is cast hollow, an insert piece 12 is placed inside the inductor, but in both cases Also, the wall of the inductor 9 facing the ingot is of the same material as the inductor, ie one of the low resistance materials, while the insert piece 12 is made of a high resistance material.

This premise also applies when several ingots are cast simultaneously with a series of devices according to the invention.

The device of the invention operates as follows.

The bottom plate is introduced into the circular hole 8 of the annular inductor 9 from below.

A voltage is applied across the inductor 9 along the power supply bus 10 and a cooling medium circulates through the cavity 14 of the inductor 9 and into the cavity 15 of the bus 10.

Molten metal is injected onto the bottom plate, the magnetic field induced by the annular inductor 9 shapes the molten metal into columns, and the columns solidify to form an outer shell.

Water is sprayed from the cavities 4 and 5 of the annular cooling means through the duct 6 onto the solidification side of the ingot 7 to promote solidification of the ingot.

As the ingot solidifies, the bottom plate is lowered and molten metal is poured from the top until an ingot of the desired size is obtained.

According to the present invention, the ingot casting phenomenon is as follows.

The current supplied by the power supply bus 10 does not dissipate at the contacts of the power supply bus 10 as it flows through the inner sidewall 13 of the annular inductor 9 .

This is because the specific electrical resistance of the insert piece 12 is significantly higher (40 to 60 times) than the steel tube from which the annular inductor 9 is made.

As a result of this, no current is dissipated and the distribution of the magnetic field along the circumference of the wall 13 of the inductor 7 facing the ingot 7 being cast is therefore more uniform.

In the embodiment currently under consideration, the molten metal is located at the annular inductor 9.
The current is concentrated on the inner conductive side wall 13 of the inductor 9.

If a hollow ingot is cast and there is metal on the outer sidewall of the annular inductor, an inductor with an insert piece on the inner sidewall (as described above) is used so that the current flows through the outer sidewall of the inductor and acts on the ingot. induces a uniform electromagnetic field.

If several ingots are to be cast at the same time, a group of devices according to the invention is operated in the same way as in the case described above, the required number of devices arranged in series depending on the purpose.

The inductor, each provided with said insert piece on either side of the point where the inductor connects with the power supply bus, homogenizes the magnetic field along the circumference of each ingot.

As a result of the test, it was found that the deviation of the ingot cast by the known method was 2 to 4 n, while the deviation of the ingot cast by the apparatus of the present invention was within 0.5 n.

The insert piece was made of stainless steel and connected to the conductive steel busbar of the annular inductor.

The width of the inductor was 15 mm and the length of the inserts was 50 m711 each.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a specific example of the device according to the present invention, and FIG.
The figure is a plan view of the inductor, and FIG. 3 is a sectional view taken along line 1-1'll of FIG. 2. 3... Annular cooling medium, 7... Ingot, 8... Circular hole opening, 9... Annular inductor, 10... Electric power supply Bus line, 12...
Insert piece, l...Insert length, a.
...Thickness of the inductor, 13... Side wall of the inductor, 14... Annular cavity of the inductor, 15...
...Electromagnetic shield.

Claims (1)

[Claims] 1. An annular hollow inductor having an annular shape defining a large opening on the inside and connected to a power supply bus, an electromagnetic shield disposed within the opening, and an electromagnetic shield disposed outside the inductor. continuous and semi-continuous casting equipment for metals comprising a cooling means, wherein the inductor is in the form of an insert piece on both sides of the connection point of the inductor connected to the power supply bus bar, and the inductor is in the form of an insert piece, The box-shaped insert piece made of a material having electrical resistivity forms a hollow part of the annular inductor together with the side wall of the inductor, and the longitudinal wall of the box of the insert piece is formed during casting. Continuous and semi-continuous casting equipment for metal, characterized in that the box is butted against the side wall of the inductor facing the ingot, and the length of the box is three times or more greater than the thickness of the inductor.