JPH05293609A - Continuous casting machine and continuous casting method - Google Patents

Abstract

PURPOSE:To separately produce extremely thick slabs having different sizes and to reduce component segregation by arranging one pair of side surface weirs which is arranged by extending over a metallic belt and a secondary cooling zone and synchronously travel with the metallic belt, and a rear surface weir which does not travel. CONSTITUTION:At the time of continuous casting, molten metal 11 is poured into a space formed with the metallic belt 1, side surface weirs 8a, 8b and rear surface weir 10. In this caster, one pair of the side surface weirs 8a, 8b, which arrange by extending over the metallic belt 1 and the secondary cooling zone 3 while arranging an interval corresponding to slab width W of the produced cast slab 7, and the rear surface weir 10, which is fixed at the fixed position between the side surface weirs 8a, 8b on the metallic belt 1, are arranged. The metallic belt 1 and the inner wall surfaces of the side surface weirs 8a, 8b are travelled while rubbing the rear surface weir 10. The poured molten metal 11 is cooled by the metallic belt 1 to form a solidified shell 12 on the metallic belt 1. In the secondary cooling zone 3, as cooling medium directly cools the back surface of the solidified shell, growing speed of the solidified shell 12 can be quickened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting machine and a continuous casting method suitable for producing a slab-shaped slab having a large plate thickness.

[0002]

2. Description of the Related Art For example, as a method for producing a slab-shaped slab having a plate thickness of about 500 mm, it is possible to produce a large steel ingot by an ordinary ingot making method. However, a large steel ingot produced by the ingot-making method has a problem that its homogeneity is insufficient due to segregation of components, and a slab-rolling machine or the like for forming a desired slab shape is required, resulting in low yield.

JP-B-53-19290, JP-A-61-
No. 14067 relates to the manufacture of extra thick slabs. That is, a flat mold consisting of a bottom surface and a side surface, which is suitable for the size of the slab to be manufactured, is assembled, the molten metal is injected into this mold, the surface of the molten metal after the injection is heated and heated, and the molten steel is cooled by cooling from the bottom surface The slab is manufactured by solidifying the molten steel in two directions by solidifying in either direction, or by cooling from the bottom and controlled cooling from the top. However, it is troublesome to assemble a mold corresponding to the size of the slab each time, and since the bottom of the mold is a surface plate, it is difficult to control the cooling rate from the bottom with sufficient accuracy.

Although not usually carried out, it is also conceivable to manufacture an extremely thick slab by using a general-purpose vertical continuous casting machine. In the vertical continuous casting machine, the slab is cut after the solidification of the center of the slab is completed. With a very thick slab, it takes a long time to complete the solidification of the central part. Therefore, in the case of an extremely thick slab, a large-scale continuous casting machine in which the distance from the mold to the slab cutting machine is extremely long is used, but it is impractical because the static pressure of molten steel becomes extremely large. Further, when an ordinary continuous casting machine is used, the injection speed is extremely reduced to perform an operation with low productivity, which is not preferable.

In the single-belt type continuous casting, the surface is cooled and the molten metal is poured onto the metal belt running diagonally upward to form a solidified shell on the surface of the metal belt and grow it to form a slab. Remove the strip from the end of the metal belt. In this single belt type continuous casting machine, solidification is completed on the metal belt. However, as already mentioned, the extremely thick slab requires a long time to complete the solidification. Therefore, an extremely long metal belt is required to manufacture an extremely thick slab, and the equipment becomes large-scale.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous casting machine which is not a large-scale facility and is capable of producing extremely thick slabs having different sizes by a simple operation. The present invention further discloses a method for producing an extremely thick cast piece having a small component segregation by using this continuous casting machine.

[0007]

FIG. 1 is an explanatory view of the present invention, (A) is a front explanatory view, and (B) is a plan explanatory view. The continuous casting machine of the present invention has a metal belt 1 whose rear surface is cooled and runs horizontally. This metal belt 1
Is a pulley with an endless metal belt at the same height.
It is obtained by straddling a and 2b and rotating the pulleys 2a and 2b in the arrow direction. Reference numeral 5 in the drawing denotes a cooling device for cooling the back surface of the metal belt 1.

A secondary cooling zone 3 is arranged at the end of the metal belt 1 in the traveling direction. The secondary cooling zone has a large number of rollers 4 and injection nozzles 6 arranged between the rollers 4. Each injection nozzle 6 injects a cooling medium, for example, water upward. A large number of rollers 4 are arranged so as to extend in the running direction of the metal belt so that the upper ends thereof are at the same height as the metal belt 1.

The continuous casting apparatus of the present invention also comprises a pair of metal belts 1 and secondary cooling zones 3 extending at intervals corresponding to the width W of the cast slab 7 to be manufactured. Side wall 8
a and 8b. The side wall weirs 8a and 8b run in the same arrow 9 direction as the metal belt 1 at the same speed.

Two or more side wall blocks, for example, 8-1, 8-2 and 8-3 in FIG. 1 (B) are detachably connected to each other in the longitudinal direction to form a side wall and run in the direction of arrow 9. As a result of the above, for example, the side wall block 8-3 which has come off from the secondary cooling zone 3
Are separated from the side surface weir 8a, transferred to the position 8-0, and sequentially connected to the tail end of the side surface weir block 8-1, the three side surface weir blocks 8-1, 8-2, 8 The side wall 8a can be formed of -3.

The continuous machine casting apparatus of the present invention also has a rear surface weir 10 disposed between the side surface dams 8a and 8b on the metal belt 1 and in close contact with the metal belt 1 and the side surface dams 8a and 8b.
The rear weir 10 does not run in the direction of arrow 9, but is provided at a fixed position. Therefore, the metal belt 1 and the side wall 8a, 8
The inner wall surface of b runs by rubbing the rear weir 10.

At the time of continuous casting, the molten metal 11 is poured into the space formed by the metal belt 1, the side surface dams 8a and 8b, and the rear surface dam 10. The poured molten metal 11 is cooled by the metal belt 1 to form a solidified shell 12 on the metal belt 1. While this solidified shell grows, it runs in the direction of arrow 9 following the running of the metal belt 1.

After reaching the end of the metal belt in the running direction, the solidified shell is supported by the roller 4. When the end of the metal belt in the running direction is reached, the unsolidified molten metal 11 remains above the solidified shell 12, but the solidified shell has grown and is already thick and has sufficient strength. There is no problem even if the support by the belt 1 is changed to the support by the roller 4. Since the unsolidified molten metal 11 is above the solidified shell 12, the side wall 8a,
8b continuously supports the side surface to prevent the molten metal 11 from flowing off from the side surface.

Even in the secondary cooling zone 3, the solidification shell 12
Is continuously cooled at its lower surface by a cooling medium such as water jetted upward from the jet nozzle 6, and grows while traveling in the direction of arrow 9 to complete solidification and become a slab 7.
The slab 7 is cut into a desired slab size by a conventional means, for example, a cutting machine (not shown) provided on the outlet side of the secondary cooling zone 3.

In the present invention, when changing the strip width W of the slab to be produced, the side wall 8 is arranged at an interval corresponding to the strip width of the slab to be produced.
Move a and 8b. The side weirs 8a and 8b normally run along a guide (not shown) arranged over the metal belt 1 and the secondary cooling zone 3, but the side weirs are moved by, for example, a pusher (not shown) or the like. The traveling paths of 8a and 8b also move, and the distance between the side weirs 8a and 8b is easily changed and set as desired.

When manufacturing an extremely thick slab, the metal belt 1
Since the depth D of the basin formed above becomes large and it takes a long time to complete the solidification, an extremely long metal belt 1 is required to complete the solidification on the metal belt 1, and the equipment is large-scale. Becomes In the present invention, solidification is not completed on the metal belt 1. On the short metal belt 1, only the initial solidified shell is formed. The secondary cooling zone 3 is a simple facility having rollers and jet nozzles. Therefore, the continuous casting apparatus of the present invention is a simple facility having a short metal belt and a simple secondary cooling zone 3.

For example, on the metal belt 1, the cooling device 5 of FIG. 1A cools the metal belt 1 and the solidified shell 12 is cooled by the metal belt 1. However, the solidified shell 12 is cooled by the metal belt 1. It is difficult to strongly cool the solidified shell 12 because it is cooled through the solidification shell 12. In the present invention, since the cooling medium directly cools the back surface of the solidification shell in the secondary cooling zone 3, it is possible to strongly cool the solidification shell 12 and increase the growth rate of the solidification shell.

Japanese Patent Publication No. 53-19290 and Japanese Patent Laid-Open No. 6-90
As described in No. 1-14067, when molten steel is cooled from the bottom surface, solidification proceeds in one direction from the bottom surface to the upper surface, and finally the upper surface or near the upper surface is solidified, inclusions and segregation components in the molten steel are generated. By concentrating on the upper surface or in the vicinity of the upper surface, an ingot with excellent cleanliness and less segregation can be obtained.

However, in a flat mold whose bottom surface is formed by an ordinary surface plate, it is difficult to control the amount of heat removed by the surface plate, so that it is difficult to proceed solidification in one direction with high accuracy and strong cooling. Further, in cooling through the metal belt 1, it is difficult to proceed solidification in one direction with high accuracy and strong cooling because, for example, an air gap occurs between the metal belt 1 and the solidification shell 12.

In the continuous casting apparatus of the present invention, in the secondary cooling zone, the cooling medium is directly jetted to the solidified shell for cooling. Therefore, by adjusting the injection amount and the injection intensity of the cooling medium, it is possible to control the cooling from the bottom surface to the strong cooling with high accuracy, and it is possible to proceed the solidification in one direction.

Reference numeral 13 in FIG. 1 (A) is an exothermic or adiabatic heat retaining agent placed on the molten metal 11. The heat retaining agent keeps the surface of the molten metal in a molten state for a certain period of time, but after a certain period of time, the heat retaining power is reduced and the surface of the molten metal is solidified. Cooling is weak and difficult to control by cooling with a surface plate or via the metal belt 1, and therefore, in the case of an extremely thick slab that has a thick cast slab to be manufactured, solidification in one direction from the bottom surface within this fixed time It is difficult to reach the molten steel surface. In the present invention, the cooling strength of the secondary cooling zone is adjusted so that the progress of solidification in one direction from the bottom surface reaches the molten steel surface within this fixed time even when the thickness of the slab to be manufactured is large. You can Therefore, when the apparatus of the present invention is used to heat or heat the upper surface of the molten metal and adjust the cooling strength of the secondary cooling zone so that the upper surface of the molten metal is finally solidified, the cleanliness is improved. An ingot with excellent segregation can always be manufactured. Although an example of the heat retaining agent 13 is shown in FIG. 1, other conventional means, such as a heat retaining cover or gas heating, can be used to retain heat or heat the upper surface of the poured molten metal.

[0022]

EFFECT OF THE INVENTION The continuous casting machine of the present invention is not a large-scale facility and is capable of producing extremely thick slabs having different sizes by simple operations such as adjusting the cutting length and moving the side dams. You can Further, by carrying out the continuous casting method of the present invention, it is possible to produce an extremely thick cast piece having excellent cleanliness and less segregation of components.

[Brief description of drawings]

 FIG. 1 is an explanatory view of a continuous casting apparatus of the present invention.

[Explanation of symbols]

1: metal belt, 2a (2b): pulley, 3: secondary cooling zone, 4: roller, 5: cooling device, 6: injection nozzle, 7: cast slab, 8a (8b): side wall, 9: metal belt , Solidification shell, running direction of side wall, 10: rear wall, 11: molten metal, 12: solidified shell, 13: heat retaining agent.

Claims (3)

[Claims] 1. A metal belt having a back surface cooled and running horizontally, a large number of rollers having upper ends arranged at the same height as the metal belt, and an injection nozzle for ejecting a cooling medium arranged between the rollers upward. The secondary cooling zone extending from the end of the metal belt in the running direction to the running direction of the metal belt and the metal belt and the secondary cooling zone with a space corresponding to the width of the cast slab being manufactured. Having a pair of side weirs that extend and run in synchronization with the metal belt, and a rear weir that does not travel and that is placed in close contact with the metal belt and the side weir between the side weirs on the metal belt. Characteristic continuous casting machine. 2. The continuous casting machine according to claim 1, wherein each side weir is a side weir formed by connecting two or more side weir blocks so as to be separable in the lengthwise direction. 3. The continuous casting machine according to claim 1 is used to inject the molten metal into the space formed by the metal belt, the side weir and the rear weir, and heat or heat the upper surface of the poured molten metal. Meanwhile, the continuous casting method is characterized in that the cooling strength of the secondary cooling zone is adjusted so that the upper surface of the molten metal finally solidifies to produce a slab.