JPS6347401Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat holding device for keeping the temperature of molten metal constant in a continuous casting apparatus.

Generally, in a continuous casting apparatus, molten steel in a ladle is once received by a tundish, and then distributed to each mold through a nozzle of the tundish for casting. Since this casting requires a long time of up to two hours per ladle, a drop in the temperature of the molten steel during this time is unavoidable.

For this reason, the tapping temperature of the furnace is generally set higher by estimating the temperature drop from the required casting time, based on the final pourable temperature of molten steel in the continuous casting equipment, and Only passive measures were taken to reduce emissions as much as possible.

However, as mentioned above, increasing the tapping temperature of the furnace, for example when an arc furnace is used as a melting furnace, not only increases the electricity consumption and electrode consumption, but also worsens the refractory consumption consumption. In continuous casting, breakouts occur frequently and problems with the quality of slabs increase, and the casting speed is likely to be restricted. In addition, in the conventional method, it was not easy to match the cycles of the steelmaking furnace and the continuous casting equipment, and there were many problems with productivity.

The present invention was developed in view of these circumstances, and is based on the upstream position of the continuous casting equipment (position just before pouring).
By making it possible to heat the molten metal, the casting temperature of the molten metal can be maintained at a predetermined temperature, thereby reducing the energy consumption and refractory material consumption, and improving the matching between the furnace and continuous casting equipment. The purpose is to make it easier to perform continuous casting operations.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example of a device to which the present invention is applied, in which a ladle 1 receiving molten steel 2 is movably provided on a tundish 4 provided on the upstream side of a continuous casting device 3. The molten steel 2 in the ladle 1 is supplied to the tundish 4 through the casting sprue 5 to create a reservoir in the tundish 4, and is then cast into the mold 7 of the continuous casting device 3 through the tundish nozzle 6. It is designed to be formed in the slab 8. The ladle 1 has an outer periphery made up of a metal enclosure 9 made of steel plate or the like, and has a trunnion 10 at the top for transportation by a crane or the like, and the inside of the enclosure 9 is not generally used. It is lined with a refractory material 11.

The heat retention device of the present invention applied to the above device is constructed as follows.

A bottom electrode 13 is provided on the metal bottom plate 12 of the tundish 4, and a tundish external connection terminal 14 is connected to the bottom electrode 13. Further, the inner surface of the side plate 15 of the tundish 4 is lined with a refractory material 11. As the details of the bottom electrode 13 are shown in FIG.
Alternatively, the tundish electrode section 16 is made of a metal structural material such as a spike material, a metal grid, or a combination thereof, and the tundish electrode section 16 is provided so as to cover the upper surface of the tundish electrode section 16 and has no effect on the components of the molten steel 2. The coating material 17 is made of a stamp material, such as zirconium oxide, MgO, etc., which has a property of ensuring high conductivity at high temperatures.

Further, a heating device 18 is provided at a position near the ladle 1 on the upstream side of the continuous casting device 3.
The heating device 18 has an electrode lifting device 19, and the lifting platform 2 is raised and lowered by the lifting device 19.
A single insertion electrode 21 provided at 0 is inserted into the ladle 1 so that an arc 22 can be formed between the tip of the insertion electrode 21 and the upper surface of the molten steel 2. A single-phase AC or DC power source 23 is connected to the insertion electrode 21, and the power source 23 is detachably connected to the tundish external connection terminal 14 of the bottom electrode 13 via a connection terminal 24. Further, the tundish 4 is provided with a thermometer (thermocouple) 25 that can detect the temperature of the molten steel within the tundish 4. Further, the connection between the tundish external connection terminal 14 and the connection terminal 24 is made using the tundish 4.
is performed automatically or remotely when the continuous casting device 3 is placed at a fixed position (casting position) on the upstream side. 26 indicates a water cooling cable.

As described above, when the tundish 4 is installed in the fixed position and the tundish external connection terminal 14 and the connection terminal 24 are connected, the ladle 1
is installed at a fixed position on the tundish 4, and the supply of molten steel 2 from the casting sprue 5 to the tundish 4 is started. Then, at this time, the molten steel 2 in the ladle 1
is electrically connected to the bottom electrode 13 of the tundish 4 via the molten steel 2' falling from the casting spout 5 (forming an electric circuit).

Therefore, if the heating device 18 is operated from the above state and the insertion electrode 21 is inserted into the ladle, an arc 22 will be created between the tip of the insertion electrode 21 and the upper surface of the molten steel 2.
The molten steel 2 can be heated by forming .
Moreover, since the temperature can be monitored by the thermometer 25, the temperature of the molten steel immediately before pouring in the continuous casting device 3 can be maintained at a predetermined value by controlling the heating device 18. Further, the heating operation may be performed intermittently or automatically based on the detected value of the thermometer 25. As the casting progresses, the upper surface position of the molten steel 2 in the ladle 1 lowers, but since the inserted electrode 21 can be moved up and down by the electrode lifting device 19, good heating can be performed accordingly.

In this way, the molten steel 2 is heated at the upstream position of the continuous casting device 3, and the molten steel temperature can be maintained approximately constant from the start of casting to the end of casting, so that the temperature drop can be prevented unlike conventional methods. Compared to the method of estimating and raising the tapping temperature of the furnace, it is possible to reduce the overall unit consumption.

Further, the bottom electrode 13 provided at the bottom of the tundish 4 connects the tundish electrode portion 16 to the covering material 17.
Since the tundish electrode part 16 is covered with a carbon fiber, the life of the tundish electrode part 16 can be extended, and the tundish electrode part 16 can melt into the molten steel 2 (if carbon is used as an electrode), thereby preventing the refined molten steel 2 from being contaminated. You can also prevent problems from occurring if you put them away.

It should be noted that the present invention is not limited to the above-mentioned embodiments; the bottom of the tundish can be made of two layers, and the heating power source can be either alternating current or direct current; however, for large capacity, direct current is preferable. Also, in the case of direct current, the insertion electrode side is generally connected to the negative pole, and although we have explained the case where the molten metal is heated by the electrode/arc method, it is also possible to use the plasma torch/plasma method.
It is also possible to install a thermometer inside the ladle for monitoring, and since the tundish tray has a small movement range, it may be configured to be connected directly to the water cooling cable, within the scope of the gist of the present invention. It goes without saying that various changes may be made therein.

According to the molten metal heat retention device in the continuous casting apparatus of the present invention described above, the following excellent effects can be achieved.

(i) The casting temperature of molten metal can be regulated and maintained immediately before casting of the continuous casting device, that is, at the tundish position, and therefore the casting temperature can be maintained accurately.

(ii) Since the casting temperature in the continuous casting device can be kept low and constant, it is possible to have flexibility in the casting speed and to improve the quality of slabs.

(iii) Possible to adjust casting time;
It becomes easier to match the steelmaking furnace and continuous casting equipment, improving the overall operating rate of all equipment, which helps improve productivity.

(iv) Since the tapping temperature in the melting furnace is lowered, the total energy consumption including melting and heat retention can be reduced.

(v) Since the tapping temperature of the melting furnace is lowered, the refractory unit consumption of the steelmaking furnace can be reduced.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figure is an explanatory diagram showing details of the bottom electrode section of FIG. 1. 1 is a ladle, 2 is molten steel, 3 is a continuous casting device,
4 is a tundish tray, 13 is a bottom electrode, 14 is a tundish external connection terminal, 16 is a tundish electrode part, 17 is a covering material, 18 is a heating device, 19
is an electrode lifting device, 21 is an insertion electrode, 23 is a power source,
24 is a connection terminal, and 25 is a thermometer.

Claims (1)

[Scope of utility model registration request] A bottom electrode equipped with a tundish external connection terminal is provided at the bottom of the tundish, and an insertion electrode is provided at an upstream position of the continuous casting apparatus to be inserted into a ladle located at the top of the tundish to heat the molten metal. Continuous casting characterized in that it is provided with a heating device comprising: a device for raising and lowering the inserted electrode; and a connecting terminal that electrically disconnects and freely attaches the inserted electrode to the tundish external connecting terminal via a power source. Heat retention device for molten metal in equipment.