JPS6234456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shell forming method in continuous slab casting equipment.

An outline of a conventional continuous slab casting equipment using twin mold rollers will be explained based on FIG. 1. Reference numeral 1 designates twin mold rollers that approach each other; reference numerals 2 and 3 designate a pinch roller and guide roller that extend downward from directly below both rollers 1 and constitute a slab conveyance path; and reference numeral 4 designates a tundish nozzle.

In the above configuration, the molten metal 5 is injected from the nozzle 4 between both rollers 1, and both rollers 1 are rotated in the direction of arrow A to pull out the slab 6. I can't get enough _H1 . Therefore, sufficient time is not given for the impurities contained in the molten metal 5 to rise to the surface of the molten metal, making it difficult to obtain a slab 6 of good quality. Therefore, a weir 7 is provided above both rollers 1 to increase the height _H2 of the molten metal, and sufficient time is taken to remove impurities by floating.However, the problem here is that when starting casting, both rollers 1 When the molten metal is injected to a height of _H2 with the rollers stopped, a shell is formed on both rollers 1,
Ciel 8 before rotating the rollers and entering steady operation.
The thickness of the shell 8 becomes too large, and when the shell 8 is sandwiched between the rollers 1, the rollers 1 receive a strong reaction force.

Therefore, the present invention provides a method for forming a shell in continuous slab casting equipment that solves these problems, and its features include twin mold rollers that are brought close to each other, and a shell forming method that is arranged on the rollers. A mold is formed with a pair of short side weirs and a long side weir consisting of a plurality of weir members in contact with each other arranged on each roller between both short side weirs, and all weir members are made into twin mold rollers. The molten metal contact area of the twin mold rollers in the mold is reduced by bringing them into contact, and then molten metal is injected into the mold to start continuous casting, and at the same time or a little later, each weir member is pulled up in sequence from the inside. This method gradually increases the contact area of the molten metal between the twin mold rollers in the mold.This method prevents the shell from increasing in thickness at the start of casting and prevents the twin mold rollers from receiving a strong reaction force. do not have. Therefore, there is no need to increase the strength of the twin mold rollers and their supporting device, and it is economically efficient, and high-quality slabs can be obtained.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 2 and 3. 10, 11 are a pair of short side weirs arranged on the twin mold roller 1; 12,
Reference numeral 13 denotes a pair of long side weirs disposed on each roller 1 between both short side weirs 10 and 11, each of which has a plurality (four in this embodiment) of weir members 12A to 12D in contact with each other. It is composed of 13A to 13D. Here, the weir members are Al ₂ O ₃ based, Al ₂ O ₃ -
Materials made of materials such as SiO ₂ based materials, Al ₂ O ₃ -ZrO ₃ based materials, and steel materials whose surfaces are coated with a refractory material are used. In addition, the long side weir 12,
13, a mold 14 is formed by short side weirs 10, 11 and rollers 1, 1. 15 is a cross beam suspended between the ends of both short side weirs 10 and 11; 16
are each cross beam 15 and each weir member 12A to 12D, 1
3A to 13D, and are rotatably supported by bearings 17 in each cross beam 15, and are synchronously rotated in one direction by a drive machine (not shown). 18A-18
C, 19A to 19C are outer weir members 12D, 13
Inner weir members 12A-12C, 13A- except for D
The weir member lifting cam is fixed to each operating shaft 16 in 13C, and when the operating shaft 16 is rotated in one direction, each cam 18A-
18C, 19A-19C are also rotated in the same direction, and the weir members 18A-18C, 19A-19C are pulled up in order from the inside.

A method for forming the shell 8 will be described based on the above configuration. First, as shown in the solid line in Figure 2, all weir members 1
2A to 12D and 13A to 13D are brought into contact with the roller 1 to reduce the molten metal contact area of the roller 1 in the mold 14. Next, a starter plug (not shown) is inserted between the twin mold rollers 1, and a tundish nozzle 4 is inserted into the mold 14 to inject the molten metal 5 into the mold 14. Then, the portion of the molten metal 5 that contacts the roller 1 is cooled and a shell 8 is formed, but the area of the shell 8 is small. Next, the roller 1 is rotated in the direction of arrow A, the starter plug is lowered, and the slab 6 is pulled out. At the same time or a little later, the operating shaft 16 is rotated in one direction. Then, the inner weir members 12A, 13A are first pulled up by the cams 18A, 19A, and the contact area of the roller 1 in the mold 14 with the molten metal becomes slightly larger. Next, cams 18B and 19B are used to
The weir members 12B and 13B are pulled up, and the contact area of the molten metal of the roller 1 in the mold 14 becomes slightly larger. Similarly, the weir members 12C and 13C are pulled up by the cams 18C and 19C, and the mold 1
The molten metal contact area of roller 1 in roller 4 is further increased slightly. When the area of the shell 8 increases by a predetermined amount in this manner, the rotation of the operating shaft 16 is stopped and normal continuous casting operation begins.

In the above embodiment, three weir members 18A to 18
I pulled up C, 19A to 19C, but only the inner two 18A, 18B, 19A, 19B or the inner 1
The shells 8 may be pulled up appropriately depending on the state of formation of the shells 8 of only the two shells 18A and 19A.

As described above, according to the shell forming method in the continuous slab casting equipment of the present invention, continuous casting is started by injecting the molten metal into the mold while reducing the molten metal contact area of the twin mold rollers in the mold. Because of this, the thickness of the shell does not increase at the start of casting, and the twin mold rollers do not receive a strong reaction force. Therefore, there is no need to increase the strength of the twin mold rollers and their support equipment, which is excellent in economic efficiency, and the mold surface height can be maintained large even at the start of casting, resulting in high-quality slabs. It is something that can be done.
Furthermore, there is no possibility that the molten metal will splash and seize the surface of the roller.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of continuous slab casting equipment using twin mold rollers, Figs. 2 and 3 show an embodiment of the present invention, Fig. 2 is a schematic longitudinal sectional view, and Fig. 3 is FIG. 1... Twin mold roller, 5... Molten metal, 6
...Slab, 8...Ciel, 10...Short side weir, 11
...Short side weir, 12...Long side weir, 12A to 12D...
...Weir member, 13... Long side weir, 13A to 13D...
Weir member, 14... Mold, 18A-18C... Cam, 19A-19B... Cam.

Claims (1)

[Claims] 1. A length consisting of twin mold rollers brought close to each other, a pair of short side weirs disposed on the rollers, and a plurality of weir members in contact with each other disposed on each roller between both short side weirs. A mold is formed with the side weir, all the weir members are brought into contact with the twin mold rollers to reduce the contact area of the molten metal between the twin mold rollers in the mold, and then the molten metal is poured into the mold to start continuous casting. A method for forming a shell in continuous slab casting equipment, which is characterized by simultaneously or slightly later pulling up each weir member from the inside in order to gradually increase the contact area of the molten metal between the twin mold rollers in the mold.