JPS59118246A - Continuous casting device for steel plate - Google Patents

Abstract

PURPOSE:To produce directly a steel plate from a molten steel while preventing bulging by disposing rolls in such a way that the inlet side of the roll gap is lower than the outlet side and drawing horizontally the steel plate from the roll gap. CONSTITUTION:A molten steel 9 flowing like an arrow in a molten steel flow passage 4 through a communicating path 6 from a tundish 7 is primarily cooled by contact with cooling rolls 1, 2 and forms a solidified layer 11. The layer 11 grows while moving in a roll gap 12 and moves in the form of a steel plate 3 having internally an unsolidified layer 13 in a horizontal direction. The steel plate receives the secondary cooling during the movement and the thickness of the layer 11 increases gradually. A flow rate regulating valve 10 is so operated that the molten steel level HA in the tundish 7 is made equal to the molten steel level HC in the layer 13 in the plate 3 during casting. The static pressure in the layer 13 in the plate 3 is thus decreased and bulging is prevented.

Description

[Detailed Description of the Invention] The present invention enables the production of steel plates directly from molten steel,
This invention relates to continuous casting equipment for steel plates that can significantly improve production efficiency, save labor on production lines, and promote energy savings.

The most common method for producing steel sheets, and one that is still practiced today, is to cast a thick slab using a continuous slab casting machine and roll it 5 to 10 times or more on a separate rolling line to make it thinner. This is a method of manufacturing a plate through a finishing rolling process in which a large number of finishing rolling mills are arranged in tandem. However, this method requires heating the slab and controlling the temperature to a constant temperature for rolling, which requires a large amount of rolling energy as well as heating energy. Furthermore, since the slab casting speed in the casting line and the rolling speed in the rolling line are significantly different, it is impossible to connect both lines, and two lines must be installed in order to cast steel plates. Therefore, not only will equipment be severely damaged, but equipment for connecting both lines will also be required.

Therefore, in order to reduce rolling energy and heating energy,
In recent years, methods of manufacturing steel sheets directly from molten steel by increasing the casting speed have been considered. One such method is a continuous casting method called the twin roll method. In this twin roll method, molten steel is introduced into two parallel cooling rolls, the molten steel is solidified on the surfaces of the rolls, and then drawn out in the form of a plate from between the two cooling rolls.

Currently, the following problems are posing problems in the practical application of the twin roll method. That is, in the twin roll method, since high-speed casting is planned, it is necessary to increase the heat transfer coefficient between the cooling roll and the solidified layer, and from this point of view, it is not possible to apply high static pressure to the molten steel. Although this is desirable, if the static pressure of the molten steel is increased in this way, there is a possibility that bulging will occur in the solidified layer immediately after exiting the twin rolls, and the unsolidified layer will flow outside.

In view of the above, the present invention applies high static pressure to molten steel to increase the heat transfer coefficient between the cooling roll and the solidified layer, and at the same time, reduces the static pressure of the internal unsolidified layer of the steel plate coming out of the cooling roll as low as possible. This was done in order to provide a continuous steel plate casting apparatus that suppresses the occurrence of bulging and makes it possible to manufacture steel plates directly from molten steel by matching the casting speed to the rolling speed.

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

Two cooling rolls (1) and (2) whose inner surfaces can be cooled with water or the like are opposed in parallel and diagonal directions with a gap corresponding to the thickness of the steel plate (3) to be cast. The cooling rolls (1) and (2) are arranged diagonally below the cooling rolls (1) and (2) to be rotatably supported by a housing (not shown).
A molten steel flow path (
4), the upper end of the flow path wall (5) communicates with the tundish (7) via the communication path (6), and a hot water storage tank is provided above the tundish (7). (8)
A flow rate regulating valve θO is provided in the flow path that supplies the molten steel (9) in the hot water storage tank (8) to the tundish (7), and the molten steel flow path ( 4
), the molten steel (9) comes into contact with the cooling rolls (1) and (2), is cooled, and solidifies sequentially from the outside to form a solidified layer 01), and the rotation of the cooling rolls (1) and (2) This solidified layer (1]) grows while moving to the roll gap (6) so that the steel plate (3) having an unsolidified layer a3 inside is sent out from the roll gap 02, and the unsolidified layer ( The steel plate (3) having passed through the roll gap 0 force with 13 is bent along the cooling roll (2) and moved in the horizontal direction, and the molten steel level HA in the tundish (7) and the molten steel flow path ( 4) Molten steel level HB and steel plate (
3) The molten steel level Hc of the unsolidified layer αe is set to HA, H6, and HB. αXun has each molten steel level HA and HB.

It shows the reference height of Ho.

In the above configuration, from Menditsch (7) to the communication path (
The molten steel (9) flowing through the molten steel channel (4) in the direction of the arrow through 6) contacts the cooling rolls (1) and (2) and is primarily cooled to form a solidified layer 01). This solidified layer 01) grows while moving into the roll gap (6) as the cooling rolls (1) and (2) rotate, and the steel plate (3) having an unsolidified layer a3 inside grows.
After passing through the roll gap (a), it is bent along the cooling roll (2) and moved in the horizontal direction, undergoing secondary cooling during the movement, and the thickness of the solidified layer Ql) gradually decreases. It will increase. During casting, the flow rate regulating valve surface is operated so that the molten steel level HA becomes equal to Ho.

In this way, the cooling roll (1
) (2) is arranged so that the steel plate (3) is pulled out horizontally, and the molten steel level H6 of the unsolidified layer α■ in the steel plate (3) is made approximately equal to the molten steel level in the tundish (7). Since the steel plate (3) is made to be able to perform casting, the static pressure of the unsolidified layer 03 in the steel plate (3) can be reduced, and bulging can be prevented.

In addition, the molten steel level HB in the molten steel flow path (4) is lower than the molten steel level salt in the tundish (7) so that the molten steel static pressure can be increased, so that the cooling rolls (1) (2) and the solidified layer 0η It can improve heat transfer between the parts and prevent air from being sucked in.

In the above embodiment, the cooling rolls (1) and (2) had the same diameter, but the cooling roll (2) on the side with the larger heat load
It is also possible to make the diameter of one of the cooling rolls (1
) side and the other cooling roll (2) side to have the same thickness, the cooling roll (1) may have a large diameter, and the cooling rolls (1) and (2) It goes without saying that they may be arranged in parallel with a required gap in the horizontal direction as well as in the diagonal direction, and that various changes can be made without departing from the gist of the vehicle invention. .

According to the present invention, as described above, (1) Since the static pressure of the unsolidified layer of the steel sheet coming out from between both cooling rolls can be reduced, bulging can be prevented and high-speed casting becomes possible. Therefore, the casting line and the rolling line can be made continuous, the conventional heating process can be omitted, and the number of times the fabric is rolled can be significantly reduced.

(11) Since the static pressure of the molten steel on the outer periphery of the cooling roll can be maintained high, heat transfer to the cooling roll can be improved and the solidified layer can grow to the required thickness. Therefore, high-speed casting is possible, and air It is possible to produce high quality steel sheets.

This excellent effect can be achieved.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing embodiments of the present invention. (1) (2)...Cooling roll, (3)...Steel plate,
(4)...molten steel flow path, (7)...tandish,
(9)...Hot water tank, α1)...Coagulation layer, (12α)
... Inlet side of the roll gap, (12b)... Outlet side of the roll gap, α Enoki... Unsolidified layer.

Claims (1)

[Claims] 1) In a continuous casting machine for steel plates, in which molten steel is guided between two cooling rolls arranged in parallel and drawn out into a plate form from the gap between the rolls, the cooling rolls are arranged so that the entrance side of the roll gap is lower than the exit side. 1. A continuous steel plate casting apparatus, characterized in that the apparatus is configured to horizontally draw out a steel plate from a gap between the rolls.