JPS62248542A - Method and apparatus for continuous casting and rolling - Google Patents

Abstract

PURPOSE:To produce a rolling directly from a molten metal with a short stage and to considerably reduce cost by casting an unsolidified ingot having a large sectional area, crushing the ingot to gradually decrease the sectional area and rolling the solidified ingot. CONSTITUTION:The molten metal 3 in a tundish 2 is poured into a roll gap part of casting rolls 1 to form the unsolidified ingot 5A having the large sectional area. The ingot is then cooled by a cooling water sprayer 4. The ingot 5A is successively decreased in the sectional area by crushing rolls 6, 7, 8 and cooling water sprayers 9, 10, 11 to form the thoroughly solidified ingot 5B. The ingot 5B is then rolled by using rolling mills 13, 14, 15 to complete a hot strip 5C. The rolling material is thus produced directly and continuously from the molten metal 3 with the shorter stage and therefore, the initial cost and production cost are considerably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous casting and rolling method and apparatus that can continuously perform the process from casting to rolling of hot strips, thick plates, shapes, etc.

[Prior Art] Current rolled materials, such as steel plates and hot strips, are produced by supplying molten metal R from a tundish f into a mold a that moves the slab to be cast out of the mold, as shown in Fig. 5. to cast an unsolidified slab, and pull it out with a feed roll p,
This is solidified while being cooled by cooling water spray C to continuously cast a long slab d, which is further divided into pieces and rolled into a predetermined shape with a small cross-sectional area using a rolling mill. There is. In addition, b is a presser roll. The manufacturing process for rolling material is a long process in which rolled material with a small cross-sectional area is made from a large cross-section of a slab, and the membrane width is large, resulting in huge construction costs, maintenance costs, labor costs, shaping energy, etc. was needed. Incidentally, FIG. 6 is an explanatory diagram of a vertical mold type casting machine, which has the same problem as the horizontal type shown in FIG.

Recently, for the purpose of reducing costs, we have developed casting machines that are smaller and capable of higher speed casting than the conventional mold type casting machines, such as twin roll type casting machines, caterpillar type casting machines, and belt/chilled roll type casting machines. etc. were devised.

Figure 7 shows a twin-roll casting machine, in which molten metal is poured from the nozzle of a tundish f between cooling rolls e and e, which have a roll gap that determines the thickness of the slab, and cooling roll e is internally cooled. The molten metal is cooled on the circumferential surfaces of rollers , e, and the slab d is continuously fed out by the rotation of the solidification zone V and the cooling rolls e and e.

Fig. 8 shows a caterpillar type casting machine, in which a pair of casters h, h coupled with a cooling mold block Q are arranged facing each other, a mold space is formed between them, and a caterpillar type casting machine is installed.
, h are moved, so that the molten metal poured from one mouth of the mold space is sent out as slab d from the other mouth.

Furthermore, Fig. 9 shows a belt/chilling roll type casting machine, in which an endless belt j is placed side by side with a cooling roll i to form a mold space, and the rotation of the cooling roll i and the movement of the belt j create a mold space. , the slab d is sent out in the same way as the caterpillar type.

[Problems to be Solved by the Invention] The mold type casting machine (Figs. 5 and 6) has a limited casting speed and cannot perform high-speed casting. Therefore, a long rolling process is required to cast a slab with a large cross-sectional area and produce strips, plates, etc. with a small cross-sectional area.

In addition, in the above-mentioned twin-roll type casting machine, if the (+) roll gap is made small, the strip can be directly cast, but because the plate thickness is thin, the molten metal that has been rapidly cooled on the circumferential surface of the cooling rolls e and e has uneven solidification. This causes cracks, scratches, wrinkles, etc., which impairs the quality of the strip. In other words, solidified shells with different temperatures are generated at the peripheral surface of the casting machine's roll, the side dam, etc., so when casting slabs that have a small cross-sectional area and are close to completely solidified, it is necessary to The lumps will be collected and shaped using the roll gap. However, each solidified mass has a different crystal structure depending on the temperature, and when these are collected, discontinuous boundaries are created, which cause cracks in the molding material.
Appears as scratches, wrinkles, etc.

(i) If the roll gap is set large, it is possible to cast slabs, thick plates, etc., but the casting speed cannot be increased because the heat loss capacity is limited.

There are other problems.

In addition, in the caterpillar type casting machine, (1) Since the small mold blocks g are coupled, slag enters the connecting gap of the mold blocks g, and a crack is formed on the casting surface of the slab d. Put it away.

0) Since the K-shaped block g is coupled, the thickness of the slab d cannot be made uniform due to thermal deformation of the mold and uneven mold formation, making it unsuitable for strip casting.

(2) Casting speed is slower than the twin roll type.

There are other problems.

Furthermore, the belt/chilled roll type casting machine has the same shortcomings as the twin roll type casting machine, as well as the fatal shortcoming of the short life of the belt j.

Therefore, the reality is that these casting machines have not yet been put into practical use.

In view of these circumstances, the present invention prevents the occurrence of board cracks, board defects, wrinkles, etc., and also prevents the occurrence of board cracks, board defects, wrinkles, etc.
The purpose is to continuously cast and roll shapes directly from molten metal in a short manufacturing process.

[Means for Solving the Problems] The present invention provides a device for supplying molten metal, a casting roll device for cooling the molten metal and casting an unsolidified slab, and a device for crushing the cross section of the unsolidified slab into a desired shape. a crushing device that transfers while
It has a configuration that includes a cooling device that cools the unsolidified slab being transferred, and a rolling device that rolls the slab that has been solidified by cooling.

[Function] (1) An unsolidified slab is cast with a casting roll device, and this unsolidified slab is sequentially cooled and solidified in a subsequent device, so that cooling and solidification of the metal progresses slowly, and the metal forms continuous crystals. Build an organization.

(2) The unsolidified slab is crushed by rolls to extrude the medium molten metal, and the ratio of the solidified area of the slab is gradually increased, resulting in a solidified slab with the required cross-sectional area.

(3) The unsolidified slab is cooled by rolling contact by crushing,
solidifies quickly.

(4) The unsolidified slab is shaped into a desired roll shape by roll crushing to reduce the cross-sectional area.

(5) Minimize rolling.

(6) By rolling the crush-shaped slab, the precision and quality of the finished product are improved.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 is a pair of casting rolls whose circumferential portions of the rolls are internally water-cooled, 2 is a tundish for pouring molten metal 3 into the roll gap of the casting rolls 1, and 4 is a tf
a first cooling water spray device for cooling the unsolidified slab 5A cast from the roll 1; 6 a first crusher for crushing the unsolidified slab 5A that has passed through the first cooling water spray device 4; Rolls 7 and 8 are second and third crushing rolls installed sequentially downstream of the first crushing roll 6, and 9.10.11 are second and third crushing rolls placed downstream of each crushing roll 6 and 7.8, respectively. 3, a fourth cooling water spray device; 12, a crop shear for cutting the front and rear ends of the completely solidified slab 5B sent through the fourth cooling water spray device 11; 13, 14, and 15, a fully solidified slab; These are the first, second, and third rolling mills that sequentially roll the hot strip 5B to form the hot strip 5C.

Now, the molten metal 3 in the tundish 2 is poured into the roll gap of the casting roll 1, and the molten metal 3 adheres to the circumferential surface of the casting roll 1 and solidifies, resulting in a cross section BIXH1 as shown in FIG. The unsolidified slab 5^ (the shaded area indicates the solidified shell) is sent out, and is cooled by the first cooling water spray device 4 to increase the thickness of the solidified shell. The unsolidified slab 5A is then crushed by the first crushing roll 6 to have a cross section 82XH2 as shown in FIG.
The solidified shell is crushed and sent out, and is cooled by the second cooling water spray device 9 to further increase the thickness of the solidified shell.

Subsequently, the unsolidified slab 5^ is passed through the second and third crushing rolls 7.8.
Cross section B3 XH as shown in Figure 2 (Jr) (-)
3. The solidified shell is sequentially crushed into B4 x H4 and cooled by the third and fourth cooling water spray devices 10.11, gradually increasing the thickness of the solidified shell, and the thickness of the solidified shell is determined by the contact cooling of each crushing roll. It also increases to become a completely solidified slab 5B. Thus, the completely solidified slab 5B has a tip with a crop shear 12.
After cutting at the first, second and third rolling mills 13.1
4.15, the hot strip 5C is sequentially rolled into cross-sections B5XH5, B6XH6, and BZXH7 as shown in FIGS. The sharp end of the completely solidified slab 5B is cut by the crop shear 12 in the same way as the tip.

The operation begins by plugging the roll gap of the casting roll 1, allowing metal to adhere to the plug, passing the unsolidified slab together with the plug through each crushing roll with a dummy bar, and removing the slab from the slab when it exits the fourth cooling water spray device 11. Remove the dummy bar,
As described above, the tip of the slab 5B is cut with the crop shear 12.

In this way, the casting roll 1 to the third rolling mill 15 are continuously cast and rolled, and the operation is continued until there is no molten metal 3 in the tundish 2. Of course, continuous operation for a long time is possible by continuously pouring molten metal into the tundish 2.

In the above, in order to prevent a discontinuous crystal structure from forming in the solidified part of the slab, the unsolidified slab 5A is cast with a casting roll 1 to have a larger cross-sectional area than the fully solidified slab 5B, and then the unsolidified slab 5A is cast with a crushing roll. The slab 5A is sequentially crushed in steps 6 and 7.8 to reduce the cross-sectional area of the slab 5A, and is transferred while increasing the solidification rate of the slab cross section. That is, when the slab 5^ is crushed by the crushing rolls 6, 7.8, the length of the outer circumference where the solidified shell is formed is constant, but the unsolidified molten metal inside is extruded from the cross section and solidified. Because it is sent at a slower speed than the shell,
The cross-sectional area is reduced and solidification is accelerated. Therefore, the pouring speed V
The relationship between e and the transfer speeds (1), (2), Vs, and v4 of 1 part of the casting roll and each of the crushing rolls 6 and 7.8 parts of the slab 5A is as follows: Ve <V+ =V2 ''Vs =Va.

Furthermore, since the fully solidified slab 5B needs to be rolled with a constant width, the transfer speeds V5, 6, and 7 of the slab 5B, which becomes the rolled material in the 13, 14, and 15 parts of the rolling mill, are Vs < VB
<V7, and the relationship between the transfer speed of the entire line is Ve <V+
=V2 =V3 =V4 <V5 <VB <V7.

Therefore, such speed conditions allow continuous operation.

In the above embodiment, the hot strip 5C, which is a thin plate, was finally manufactured, but by setting the roll gap of the casting roll 1 to a large value, a thick plate can be manufactured. Further, as shown in FIG. 3, the third rolling mill 15
By arranging the dividing shear 16, the first and second down coilers 17 and 18, and the runout table 19 further downstream, a dual-use design is created that allows production of both thin plates and thick plates.

Alternatively, the equipment may be arranged so that casting and rolling are performed not as a continuous metal piece but as individual cut metal pieces.

In this way, in the present invention, both thin plates and thick plates can be manufactured.
By devising the shape of the roll in Figure 4 (I
) (c) ← Bajo) (f) (g) It is also possible to manufacture a section steel as shown in (g).

In this embodiment, an example of a horizontal arrangement is shown, but an arrangement using a vertical casting device may also be used. Furthermore, it goes without saying that the present invention can be applied to metals such as iron and non-ferrous metals. Furthermore, although a crushing roll was used to crush the slab, other crushing devices may be used.

[Effects of the Invention] As explained above, according to the continuous casting and rolling method and apparatus of the present invention, (I> Since a solid cast piece is cast into a single piece with a large cross-sectional area and the cross-section is reduced by crushing, , defects such as cracks, scratches, and wrinkles caused by uneven solidification of molten metal are eliminated, improving product quality.

<n> Since it can be cast in a cross-sectional shape that is easy to cast, and then formed into the required new surface shape by crushing, not only natural strips but also slabs such as shapes and plates can be made in lengths of 1 m.

[Phase] Since the cooling and solidification of the slab is accelerated by crushing contact, the cooling device can be made smaller compared to conventional mold casting machines.

■ Since the cross-sectional area is greatly reduced by crushing, the rolling process is minimal, and the conventional rolling process can be shortened.

(V) The quality and precision of the product produced by rolling is better than that produced by only casting.

■ As a result of the above, it is possible to continuously cast and roll rolled materials directly from molten metal using small-scale equipment, and the construction costs of production equipment, costs for manufacturing rolled materials, labor, maintenance costs, etc. are significantly reduced compared to conventional methods. can.

It can produce excellent effects such as

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the continuous casting and rolling apparatus of the present invention, and Figure 2 (
A) to (G) are diagrams showing changes in cross-sectional shape, FIG. 3 is a partial view of the continuous casting and rolling apparatus of the present invention configured as a device for both thin plate and thick plate, and FIGS. ) is a diagram showing changes in the cross-sectional shape when manufacturing a section steel using the apparatus of the present invention, and FIG. 5 is an explanatory diagram of a conventional horizontal mold casting machine.
Figure 6 is an explanatory diagram of a vertical mold type casting machine, Figures 7 to 9
The figures are all explanatory diagrams of casting machines that have been recently considered. 1 is a casting roll, 3 is a molten metal, 4, 9, 10.11 is a cooling water spray device, 5A is an unsolidified slab, 5B is a fully solidified slab, 5C is a hot strip, 6.7.8 is a crushing roll , 13.14.15 indicates a rolling mill. Figure 9

Claims (1)

[Scope of Claims] 1) Molten metal is cooled on the circumferential surface of rotating rolls, the molten metal is cast into an unsolidified slab surrounded by a solidified shell, and the unsolidified slab is crushed while being transferred. The cross-sectional area of the slab is reduced by extruding hot water, the cross-section of the slab is shaped into the desired shape by this crushing, and the slab is further rolled into metal pieces of the desired shape to continuously produce rolled products from the molten metal. A continuous casting and rolling method characterized by: 2) A device for supplying molten metal, a casting roll device that cools the molten metal around the rolls and casts the molten metal into an unsolidified slab surrounded by a solidified shell, and a casting roll device that cools the molten metal around the rolls and casts the unsolidified slab into an unsolidified slab while transporting the unsolidified slab. A slab crushing device that crushes the slab into a shaped cross section and extrudes a medium molten metal to reduce the cross-sectional area of the slab, a slab cooling device that cools and solidifies the slab to be transferred, and a rolling device that rolls the cooled slab. , a continuous casting and rolling apparatus characterized in that it continuously produces rolled products from molten metal.