JPH0335017B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for directly and continuously casting a wide thin plate from molten metal, particularly molten steel, using a surface moving mold that moves synchronously with the slab.

In continuous steel casting, proposals have been made to manufacture wide thin plates directly from molten steel by casting instead of conventional thick slabs. For example, an invention that attempts to directly manufacture thin plates from molten steel using a synchronously rotating mold consisting of twin rolls or twin belts,
JP-A-55-75862, JP-A-57-9566, JP-A-Sho
It is described in No. 58-32548 and Japanese Unexamined Patent Publication No. 58-32551. The basic principle of these is that, as shown schematically in Figure 1, casting is performed by a pair of cooled casting rolls (or casting belts) placed opposite each other with a predetermined gap corresponding to the thickness of the slab. surface-moving molds 1a, 1b, and the width of slabs placed oppositely on top of the surface-moving molds 1a, 1b with a gap corresponding to the width of the slab, which is within the width of the surface-moving molds 1a, 1b. A pair of fixed walls 2a for regulation,
2b (this fixed wall in the figure) is used to continuously cast thin plate slabs.

There are various problems in realizing continuous casting of thin plates using such a moving surface mold, but among them,
Non-uniform cooling rate in the width direction of the slab (fixed wall 2a,
2b (the cooling rate is faster on the slab side), problems such as uneven plate thickness, lamination, and generation of hot water wrinkles, as well as gaps between the lower edges of the fixed walls 2a and 2b and the surface-moving mold. A major issue is how to solve problems such as the occurrence of hot water burrs on both sides of the slab and the occurrence of solidification shells getting stuck when hot water is inserted into the slab.

The present invention has been made to solve these problems, and consists of a movable mold surface formed by a pair of casting rolls or a casting belt that are arranged facing each other with a predetermined gap corresponding to the thickness of the slab. , fixed walls facing each other on the surface of the movable mold with a gap corresponding to the width of the slab. An applicator roll having a length greater than the width of the slab is installed in contact with the surface of the moving mold, and an auxiliary roll that rotates in the opposite direction to this applicator roll is placed in contact with the applicator roll. A high viscosity lubricant and a low viscosity lubricant are applied to the V-shaped curved surface formed by the auxiliary roll, the former being applied to the moving mold surface in contact with the fixed wall, and the latter being applied to the part between the fixed walls. It is characterized in that it is supplied so that it is applied to the surface of the moving mold that comes into contact with the molten metal. Note that the word "contact" used here as "the surface of the movable mold in contact with the fixed wall" actually means contact through a lubricant, and the fixed wall and the surface of the movable mold are not necessarily directly connected. This includes cases in which they are not in close contact with each other. The device for carrying out this method consists of a movable mold surface formed by a pair of casting rolls or casting belts that are placed opposite each other with a predetermined gap corresponding to the thickness of the slab, and and a fixed wall facing above the surface of the movable mold with a corresponding gap therebetween to form a continuous casting mold. A coating roll having a length at least greater than the width of the slab is installed on the surface, and an auxiliary roll that rotates in the opposite direction to this coating roll is placed in contact with the surface of the coating roll. An apparatus for continuous casting of thin plate slabs has been devised, characterized in that a plurality of nozzles for supplying a coating agent are disposed between the auxiliary roll in contact with the auxiliary roll and the auxiliary roll.

Figure 2 shows an example of an apparatus in which the method of the present invention is applied to a moving surface mold using casting rolls.
Similarly to the figure, a pair of cooled casting rolls (hereinafter referred to as moving mold surfaces 1a and 1b) that rotate in opposite directions and are arranged facing each other with a gap corresponding to the thickness of the thin plate slab 3, and a slab This figure shows an example in which a thin plate continuous casting mold is constructed by fixed walls 2a and 2b that are arranged oppositely on the movable mold surfaces 1a and 1b with an interval corresponding to the width of 3. The fixed walls 2a, 2b for regulating the slab width are connected to long side walls 4a, 4b installed perpendicularly thereto on the movable mold surfaces 1a, 1b, and the other side wall forming a sump container. It's summery. The long side walls 4a, 4b are
It plays the role of retaining a sufficient amount of molten metal while preventing the backflow of molten metal to the moving mold surfaces 1a and 1b that are about to head towards the casting space. In the case of equipment that forms deep valleys that can hold ), this long side wall 4
In some cases, the fixed walls 2a, 2b and the movable mold surfaces 1a, 1b can form a sump vessel without the need for a, 4b.

In any case, the present invention provides, in such a surface moving type casting apparatus, the following:
A lubricant having a different viscosity is applied depending on the location. More specifically, a high viscosity semi-liquid lubricant, such as grease, is applied to the surface of the moving mold toward the location where the fixed walls 2a and 2b are present. Then, a low-viscosity semi-liquid lubricant, such as fluid graphite, silicone oil, or castor oil, is applied to the surface of the moving mold that is about to come into contact with the molten metal between the fixed walls 2a and 2b. The former highly viscous semi-liquid lubricant is applied to the movable mold surfaces 1a and 1b and the fixed wall 2.
The low viscosity semi-liquid lubricant is filled into the gap between the molten metal and the moving mold surface and provides a sealing effect to prevent the molten metal from entering the gap. By forming a uniform film between the molten metal and the moving mold surface, direct contact between the molten metal and the surface of the moving mold is avoided, and the molten metal has a gradual cooling effect and an anti-seizure effect.

Referring to FIG. 2, a preferred example of an apparatus for carrying out this process will be described in detail.The shaft is parallel to the flat surface of the movable mold surfaces 1a, 1b so that the roll surfaces are in contact with the flat surfaces of the surfaces 1a, 1b. Then, the application rolls 5a and 5b are installed. The applicator rolls 5a, 5b are rolls having a width at least longer than the width of the slab 3, and the moving mold surfaces 1a, 1
It rotates in response to the movement of b. Then, auxiliary rolls 6a, 6b rotating in the opposite direction to the application rolls 5a, 5b are installed so that the application rolls 5a, 5b and the roll surfaces are in contact with each other. That is, both rolls are installed so that a groove having a V-shaped curved surface is formed on a line of contact between the two rolls by the roll pair of the application roll and the auxiliary roll that are in contact with each other. A plurality of nozzles 7 and 8 supply lubricant to the V-shaped curved groove formed on the contact line of both rolls.
will be installed.

The nozzle 7 is a nozzle that supplies a high-viscosity lubricant, and the high-viscosity lubricant is applied to the positions of the movable mold surfaces 1a and 1b that are about to go to the parts corresponding to the fixed walls 2a and 2b. , said V
The discharge ports are directed toward both ends (at least four locations) of the curved groove.

On the other hand, the nozzle 8 is a nozzle for supplying a low-viscosity lubricant, and this low-viscosity lubricant is applied to the moving mold surfaces 1a and 1b, which are about to go to the part between the fixed walls 2a and 2b that comes into contact with the molten metal. The discharge port is directed toward the V-shaped groove closer to the center than the nozzle 7 so that the agent can be applied.

With this configuration, a quasi-liquid high-viscosity lubricant such as grease is always present on the surfaces of both sides of the applicator rolls 5a and 5b (corresponding to the positions of the fixed walls 2a and 2b), and this is applied to the fixed walls 2a and 2b. and the movable mold surfaces 1a, 1b, and can effectively prevent hot water from entering this gap, and
For example, fluidized graphite (fine powder graphite dispersed in an oil-based dispersion medium) is always present on the center side between the grease rings of the application rolls 5a and 5b, and this flows between the fixed walls 2a and 2b. It is uniformly supplied onto the movable mold surfaces 1a and 1b in contact with the molten metal, and the presence of this uniform film of graphite provides a slow cooling effect and an anti-seizure effect. This slow cooling effect is
It alleviates the difference in cooling rate depending on the location (the cooling rate is faster on the side of the fixed walls 2a and 2b), helps to make the thickness of the solidified shell uniform, and therefore the plate thickness, and causes defects such as cracks on the plate surface. It will also help prevent. Furthermore, the anti-seizure effect prevents damage to the surface-moving mold, and enables stable continuous casting of thin plate slabs with good surface properties.

Note that the same configuration can be adopted when a belt is used as the movable mold surfaces 1a and 1b instead of the illustrated casting roll, and the same effect can be achieved.

As described above, according to the present invention, the problem of the occurrence of hot water burrs due to the insertion of hot water into the gap between the fixed wall and the solidified shell of irregular shape, which were problems in continuous casting of thin sheets, can be solved by the above-mentioned problem due to the difference in cooling rate. Since the problems are also effectively solved at the same time, the invention is particularly useful for carrying out direct casting of thin plate slabs from molten steel.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing an outline of a typical example of a conventional thin plate continuous casting apparatus, and FIG. 2 is a general view showing an example of an apparatus for carrying out the method of the present invention. 1a, 1b... moving mold surface, 2a, 2b...
Fixed wall, 3...Thin slab, 4a, 4b...Long side wall, 5a, 5b...Applying roll, 6a, 6b...
Auxiliary roll, 7...High viscosity lubricant supply nozzle, 8
...Low viscosity lubricant supply nozzle.

Claims (1)

[Claims] 1. A movable mold surface formed by a pair of casting rolls or casting belts that are placed opposite each other with a predetermined distance corresponding to the thickness of the slab, and a width corresponding to the width of the slab. When continuously casting a thin plate by supplying molten metal to a continuous casting mold consisting of a fixed wall disposed oppositely above the surface of the movable mold with a gap in between, a coating roll having a length is placed in contact with the surface of the moving mold, and an auxiliary roll rotating in the opposite direction to the coating roll is placed in contact with the coating roll,
A high viscosity lubricant and a low viscosity lubricant are applied to the V-shaped curved surface portion formed by the applicator roll and the auxiliary roll so that the former is applied to the moving mold surface in contact with the fixed wall, and the latter is applied to the moving mold surface in contact with the fixed wall. A method for applying a lubricant in continuous thin plate casting, characterized in that the lubricant is supplied so as to be applied to the surface of a moving mold in a portion between walls that is in contact with molten metal. 2. A movable mold surface formed by a pair of casting rolls or casting belts placed opposite each other with a predetermined distance corresponding to the thickness of the slab, and a movable mold surface formed by a pair of casting rolls or casting belts placed opposite each other with a predetermined distance corresponding to the thickness of the slab. In a thin plate continuous casting apparatus that constitutes a continuous casting mold by a fixed wall disposed facing above a surface of a moving mold, at least one of the slabs is placed in contact with the surface of the moving mold before moving to a part in contact with the molten metal. A coating roll with a length greater than its width is installed, and an auxiliary roll rotating in the opposite direction to this coating roll is placed in contact with the surface of this coating roll, and the relationship between this coating roll and the auxiliary roll in contact with it is A thin plate continuous casting apparatus characterized by having a plurality of nozzles arranged between which a coating agent is supplied.