JPH02210789A - High frequency heating coil for horizontal continuous casting - Google Patents

Abstract

PURPOSE:To obtain a product of good quality by keeping molten raw metal stayed in a crucible uniformly and efficiently with application of inductive heat. CONSTITUTION:Assuming that each interval of coils 2 is set at d2 on the front side of a crucible 1 while at d3-d5 from the top on the back side thereof, d3>d4>d5 so that the coils 2 surround the crucible 1 on the back side thereof from the upper portion to the lower portion. Accordingly, it is possible to produce a sufficient heating effect on the crucible and reduce a difference between temperature of molten liquid at the upper portion of the crucible and that at the lower portion thereof. therefore. The intervals between the coils are changed in accordance with the structure of the crucible so that the molten raw metal stayed in the crucible can be uniformly kept with application of heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high frequency heating coil for horizontal continuous casting of metals such as iron, copper, lead, aluminum, nickel, precious metals, etc. and alloys thereof.

[Prior art] High-frequency heating coils for continuous casting are widely used to hold raw metal in heated and molten crucibles, and are energy efficient, easy to control temperature, and easy to automatically control, and especially This is because it has the excellent feature of causing little pollution. Conventionally, high-frequency heating coils used in the above-mentioned fields have generally been cylindrical coils with equally spaced windings.

[Problems to be solved by the invention] There are two types of continuous casting crucibles depending on the method of drawing out the finished product.In the case of a vertical crucible, there is no die or cooling jacket on the side wall in order to pull out the finished product from the bottom of the crucible. Conventional high-frequency heating coils can surround the entire crucible and heat it evenly. However, in the case of a horizontal crucible, the product is ejected horizontally from the side wall, so the die and cooling jacket get in the way, and the heating coil cannot surround the bottom of the crucible. Heating tends to be insufficient.

For example, as shown in Fig. 3, in a casting device that uses a conventional horizontal high-frequency heating coil for continuous forming (hereinafter simply referred to as a coil), heated and molten raw metal is placed in a crucible 1, and the windings are spaced evenly apart. The molten metal 3 is heated and maintained by a cylindrical coil 2 of di, and is drawn out from the hot water inlet 4 through a die 6 surrounded by a cooling jacket 5 and in contact with the lower part of the side wall of the crucible to form a finished product 7.

However, the coil 2 has a die 6, a cooling jacket 5
Since the lower part of the crucible cannot be surrounded by the molten metal, the heating in the vicinity of the hot water supply port 4 becomes insufficient compared to the upper part of the crucible, and smooth withdrawal of the molten metal 3 is hindered. If the heating power is increased to bring the temperature near the hot water supply port 4 to an appropriate temperature, the temperature at the top of the crucible will rise excessively, which will adversely affect the quality of the cast product and shorten the life of the crucible 1, leading to disadvantageous results in casting. There was a problem.

[Means for Solving the Problems] As a result of various studies to solve the above-mentioned problems, the present inventor has achieved the present invention in a cylindrical high-frequency heating coil with multiple turns surrounding a crucible. Therefore, the first invention widens the winding interval from the front side of the crucible toward the back side,
It is characterized by a winding that surrounds the crucible from the top to the bottom at the back.

The gist of the second invention is a high-frequency heating coil for horizontal continuous casting, characterized by comprising two coils surrounding a portion above and below a die of a crucible.

By using the above-mentioned coil, the interval between the windings can be changed according to the structure of the crucible, and the molten raw metal in the crucible can always be uniformly heated and maintained.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the first invention, where the winding spacing of the coil 2 on the front side of the crucible is d2, and the spacing on the back side is d, ~d5 from above, d,>d4>d , then the coil winding surrounds the back side of crucible 1 from top to bottom,
The heating effect was sufficient and the temperature difference between the molten metal at the top and bottom of the crucible could be reduced.

When the empty crucible was heated using the conventional coil shown in Figure 3, the lower part was black even though the upper part was red hot, but in the case of Figure 1, the lower part was red hot and the effect of the present invention was demonstrated. I was able to confirm.

FIG. 2 shows an embodiment of the second invention, in which the coil is divided into upper and lower parts with the die 6 as a boundary, so that the entire crucible is heated and maintained uniformly. In conventional coils, a temperature difference of 50°C or more occurred between the molten metal at the top and bottom of the crucible, but with the coil of the present invention, the upper part of the coil is wound 8 to 10 times and the lower part is wound 2 to 5 times. , it was possible to suppress the temperature difference to about lθ°C.

If a hollow copper pipe is used as a coil and cooling water is passed through it, a large current can be passed through a thin winding, making the coil smaller. Furthermore, by connecting the upper and lower coils using a copper pipe or a loop nut, power can be supplied from a single power source.

In addition, the coil of the present invention is effective not only for casting in an air atmosphere but also in a low S atmosphere including a vacuum, and good casting results have always been obtained for raw metals ranging from copper alloys with high melting points to solder alloys with low melting points. .

[Effects of the Invention] According to the present invention, the molten raw metal in the crucible is uniformly and efficiently held under induction heating, so that it can be smoothly drawn out through the die and a high-quality product can be obtained.

[Brief explanation of the drawing]

FIG. 1(a) is a longitudinal cross-sectional view of a metal casting apparatus using the high-frequency heating coil of the present invention, FIG. 1(b) is a front view of the crucible and coil of FIG. 1, and FIG. FIG. 3 shows a vertical cross-sectional view of a metal casting apparatus using a high-frequency heating coil, and FIG. 3 shows a vertical cross-sectional view of a metal casting apparatus using a conventional high-frequency heating coil. 1... Crucible, 2... High frequency heating coil, 3...
・Molten metal, 4... Hot water supply port, 5... Cooling jacket, 6... Dice, 7...
・Finished product.

Claims (1)

[Claims] 1) In a multi-turn cylindrical high-frequency heating coil that surrounds the crucible, the interval between the windings is widened from the front of the crucible to the back, and the winding surrounds the crucible from the top to the bottom on the back. High-frequency heating coil for horizontal continuous casting. 2) A high-frequency heating coil for horizontal continuous casting, characterized in that the multi-turn cylindrical high-frequency heating coil surrounds a crucible and consists of two coils surrounding a portion above and a portion below the die of the crucible.