JPS6138757A - Tundish heater - Google Patents

Abstract

PURPOSE:To provide a titled device which can be relatively easily attached and detached to and from a tundish by drilling communicating holes at a prescribed interval to a shielding block provided between a molten metal receiving chamber and pouring chamber and inserting attachably and detachably a core having an induction heating coil into a through-hole. CONSTITUTION:The shielding block 5 consisting of a refractory material is formed between the molten metal receiving chamber 1a and pouring chamber 1b to the inside of the tundish body 1 of a continuous casting machine. The two communicating ports (not shown in figure) communicating with the tap hole of the chamber 1a and the chamber 1b are drilled at a prescribed space to the block 5 and the core 4 having the induction heating coil 4a is attachably and detachably inserted into the vertical through-hole 6. The block 5 is more preferably molded preliminarily to a prescribed shape and installed attachably and detachably to the prescribed position of the core 1. The heater constituted in the above-mentioned way heats efficiently and inductively the molten steel in the tundish 1 and is relatively easily attachable together with the refractories to the tundish.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to a heating device for a tundish in a continuous casting machine.

[Prior art and its problems 1 Continuous casting machines mainly used in the steel industry are equipped with a tundish as a device for pouring a fixed amount of molten metal and removing impurities from the molten metal before molding. The tanditshu itself was not equipped with a heating device. Therefore, once the temperature of the molten metal drops in the tandish,
There were cases where the molten steel was separated in the vicinity of the tap nozzle of the tundish. Once the molten steel becomes individualized, a large amount of energy is required to remelt it, which is extremely uneconomical, and there is also a large loss due to the suspension of operations.

To solve this problem, a heating device may be provided in the tundish itself, but in preparation for replacing the refractory material of the tundish, etc., the heating device must be configured to be relatively easily attached to and removed from the tundish.

[Objective of the Invention 1 This invention was made to solve the above-mentioned problems, and its main object is to provide a tundish equipped with a heating device. Another object of the present invention is to provide a heating device having a structure in which both the heating device and the refractory material can be attached to a tundish relatively easily.

[Structure 1 of the Invention In this invention, a shield block is provided between the hot water receiving chamber and the hot water pouring chamber of the tundish, and an induction heating coil is installed in the hole provided in this shield block. A flow path for the molten metal is provided, and the magnetic field generated by the induction heating coil and the current path for the molten metal are interlinked to inductively heat the molten metal. The heating coil can be easily attached to the shielding block.

Embodiment 1 of the Invention In FIG. 1, a tundish main body 1 includes a protective casing 2 made of a generally rectangular steel plate, and a protective wall 3 made of a fireproof material provided on the inner periphery of the protective case 2. A core 4 for induction heating is attached to the center of the tundish main body 1, and a shield block 5 for partitioning into a hot water receiving chamber 1a and a pouring chamber 11 is removably installed.

As shown in Fig. 3, the shield block 5 is made of a generally rectangular fireproof material, and a through hole 6 for inserting the core 4 is vertically opened in the center thereof, and a through hole 6 is vertically opened in the center of the shield block 5 to allow the core 4 to pass therethrough. Communication holes 7 and 8 for communicating with the hot water chamber 1b are formed at the bottom of the shielding block 5 and located on both sides of the through hole 6.

The bottom of the communication hole 7.8 can be heated as much as possible by the last molten metal core, and the riser can be raised as close as possible to the bottom of the tundish to prevent pinching.

The shielding block 5 is manufactured in advance in the form of a cassette so that it can be fitted into the tundish main body, separately from the manufacture of the tundish main body 1. This is due to the following reasons.

(i) When molding blocks on-site, it takes time to install and dry the refractories, which reduces the operating rate of the tanditshu.

(ii) Furthermore, since the fireproof structure formed in this manner is constructed in an environment with poor workability, the dimensional accuracy of each part of the structure is low. As a result, the following problems arise.

b) The shape of the groove that serves as a current path during induction heating and the correlation between the groove and the coil become inaccurate, resulting in inaccurate electrical characteristics during heating, which makes heating control difficult.

口) It becomes difficult to secure the gap between the refractory, fill, and core, making it difficult to assemble the coil and core.

c) The gap between the refractory and the coil (iron core) is a path through which cooling air flows between the refractory and the coil, but if this gap is uneven, it will lead to an inability to obtain a stable wind cooling effect.

The above problems are solved by prefabricating the shielding block 5 in cassette form, as shown in this embodiment.

At the time of manufacture, the protective wall 3 is formed in a U-shape as shown in Fig. 3, and the shielding block 5 is fitted into the space 9 where the protective walls 3, 3 face each other, and the bottom surface of the shielding block The book 4 is installed so as to be in contact with a floor (not shown) made of fireproof material laid at the bottom of the unit 1, and the contact area between the protection wall 3 and the floor etc. and the barrier block 5 (as shown in 11) ) is sealed with cement, etc.

The core 4 is formed into a rectangular ring shape, and an induction heating coil 4a is wound around one leg of the core 4, and this coil 4a is fitted into the through hole 6 of the jacket block 5. The magnetic field generated by the coil 4a acts vertically across the molten metal within the tundish body 1.

Note that insulating gaps 12 are provided in the protective housing 2 in the vertical direction at appropriate positions in order to avoid the generation of a one-way current path due to the above-mentioned magnetic field.

In the tundish constructed as described above, when molten metal is supplied to the molten metal receiving chamber 1a, the molten metal passes through the communication hole 7.8 and is also stored in the molten metal pouring chamber 1b. Therefore, the molten metal present in the molten metal receiving chamber 1a, the molten metal pouring chamber 1b, and the communication holes 7 and 8 forms a one-round current path.

Here, by supplying alternating current to the heating coil 4a and exciting the core 4, the magnetic field passing through the core 4 and the current path formed by the molten metal passing through the communication holes 7 and 8 are linked, thereby increasing the current path. Induces a current. Then, Joule heat is generated in the molten metal in the communication holes 7 and 8, and the molten metal can be heated.

The heated molten metal is optionally poured out toward the strand (not shown) from the spout 13 by opening and closing a nozzle (not shown).

Figures 6 and 7 show an embodiment of the pond of this invention.
A hot water receiving chamber 1a is provided in the center of the tundish main body 1, and a hot water pouring chamber 111 is provided on both sides of the hot water receiving chamber 1a, and two shield blocks 5 are provided on both sides of the hot water receiving chamber 1a. Components that are the same as those in the embodiment shown in FIG. 1 are given the same reference numerals and their explanations will be omitted.

In addition, in FIG. 7, 14 is a device for attaching and detaching the core 4.

In each of the above-described embodiments, the poppy block 5 is made of refractory material pre-molded into a predetermined shape and fitted into a predetermined position of the tundish main body 1, which facilitates assembly work and improves durability. There is no need to dry the person, so the time required for refractory construction can be shortened and the work can be done quickly.

Moreover, the positional relationship with the core 4 can be made accurate, and the electrical characteristics of the induction heating furnace can be made accurate.

Note that the present invention is not limited to the above-mentioned embodiments, and can be applied to various deformation forces. For example, the communication holes 7 and 8 can be
It is also possible to form a groove on the bottom surface of the plate as shown in 71.31. Others include Tanditshu, Shiyahei Block,
The shape of the core etc. can be selected arbitrarily.

In the above-mentioned tundish, when a large current flows through the communication grooves 7 and 8, that is, the flow path, the currents attract each other, so that the molten metal in the flow path receives a force in a direction that contracts the cross section. This effect is generally referred to as the pinch effect. Here, the force at this time will be referred to as the pinch force.

When the pinch force is large and the static pressure applied to the flow path is small, the cross section of the molten metal in the flow path is reduced, eventually resulting in the cutting of the cross section and the current path. In such a case, electric power for heating cannot be supplied stably, so that the heating device cannot function as a heating device.

Here, the occurrence of a cutting phenomenon in the molten metal is called "pinch occurrence", and the height from the communication groove to the molten metal surface, which corresponds to the static pressure of the molten metal, when "pinch occurrence" occurs when power is turned on is defined as This is called the “pinch hot water height.”

This pinch-generating molten metal height H (cn+) is applied to a normal groove-type induction heating furnace. F, according to Walter's equation.

However, N2: Electric power (KW) generated in molten steel δ:
Molten metal density (g/am3) ρ: Specific resistance (Ω-ell) j2: Groove length
(cm) From equation (1), it can be seen that the height of the molten metal at which a pinch occurs is proportional to the electric power N2 generated in the molten steel. However, this may be proportional to the input power of the heating device since the electrical efficiency of the heating device is approximately constant.

At the end of continuous casting, the supply of molten metal to the tundish ceases and the molten metal level continues to drop, but during this process the molten metal height changes to the formula (
If it becomes lower than 1) H, a pinch will occur and the electrical circuit will be cut off by the molten metal, making it impossible to supply power.

Therefore, the bottom of the communication hole is aligned with the bottom of the tundish in order to heat the molten metal as much as possible with the last molten metal and to hold the riser to prevent pinching.

[Effects of the Invention 1] As detailed above, the present invention provides an island-shaped shielding block made of a fireproof material in the tundish, and inserts the cavity of the induction heating device into the hole formed in the shielding block. The molten metal is passed through the communication part provided in the jamb block, and the current path caused by the molten metal interlinks with the magnetic field for heating.The molten metal is heated in the tundish to prevent the metal material from solidifying. Therefore, wasteful consumption of heating energy can be prevented, and the induction heating device can be easily attached to the tundish.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the tundish of the present invention, FIG. 2 is a perspective view showing an example of the core used in the embodiment of FIG. 1, and FIG. 3 is an exploded view of the embodiment of FIG. 1. Perspective view,
4 is a perspective view showing the tundish of the embodiment shown in FIG. 1 with the core removed, FIG. 5 is a plan view of the embodiment shown in FIG. 1, and FIG.
The figure is a plan view showing an embodiment of the pond of this invention, and FIG.
It is a disconnection diagram along the line AA of the embodiment shown in the figure. 1...tanditshu main body, 1a... hot water receiving room,
11)...Pouring chamber, 2...Protection casing, 3...Protection wall 4...Core, 5...Kayahei block, 6...
Through hole, 7, butt... communicating hole, 9... space, 13...
Pouring spout.

Claims (2)

[Claims] (1) In the tundish of a continuous casting machine, a shielding block made of refractory material is formed between the molten metal receiving chamber and the molten pouring chamber, and this shielding block has two molten metals connected to the molten metal receiving chamber and the pouring port. A tundish heating device characterized in that holes are formed at predetermined intervals, and a core having an induction heating coil is removably connected to the hole that vertically communicates with the shield block. (2) In the tundish heating device according to claim 1, the shielding block is a cassette-type block that is pre-molded into a predetermined shape and is removably installed in a predetermined position of the tundish. .