JPH07314096A - Spray cooling type mold in continuous caster - Google Patents

Abstract

PURPOSE:To obtain a mold cooling device preventing uneven solidification, deformation, crack, etc., of a cast slab by intensely cooling the upper part of the mold by spraying and weakly cooling the lower part thereof. CONSTITUTION:Cooling water supplied from a cooling water supplying passage 11 is stored in a lower cooling header 8 and thereafter, a forced water passage 6 paralleled to the mold surface is formed upward from the lower part in a cooling jacket 5 formed between a water passage forming plate 9 and the mold body 1 to cool the lower part B of the mold. The cooling water cooled to the lower part B of the mold is guided into an upper pressing tube 7, and the spray water 4 is sprayed to the upper part A of the mold through spray nozzles 3 arranged at a prescribed position and in a prescribed pitch of the upper pressing tube 7 to cool the upper part A thereof. This cooling water is guided to a cooling water draining passage 12 through a lower water draining chamber 14. By this constitution, even at the time of casting in high speed, the mold is efficiently cooled with a small quantity of the cooling water, and the upper part thereof is uniformly and intensely cooled and the lower part thereof is weakly cooled, and the troubles, such as the uneven solidification, deformation, crack, of the cast slab are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a spray cooling type mold for a continuous casting machine.

[0002]

2. Description of the Related Art As a conventional method for cooling a mold in a continuous casting machine for steel, a forced water flow cooling method in which cooling water is passed through the mold cooling surface at high speed to cool it, or a cooling water is sprayed on the mold cooling surface. There is a spray cooling method that cools by means of cooling.

These conventional mold cooling methods include:
Japanese Unexamined Patent Publication No. 63-104753 (forced water flow cooling method), Jikken 1-60746 (Spray cooling method)
Etc. can be mentioned.

[0004]

However, the conventional mold cooling method has the following problems. That is, (1) In the case of the forced water flow cooling method, as shown in FIG.
A cooling water passage is formed behind the mold surface. At the meniscus where the heat load is the largest in the mold, a very high speed (8 m / sec or more) is used to prevent the formation of a vapor film during water flow cooling. ), It is necessary to pass cooling water, and a large amount of cooling water is required. Further, in this case, since the cooling strength from the lower part to the upper part of the mold is almost the same as the cooling water flow rate, the cast slab to be cast is supercooled at the mold outlet.
When the slab is overcooled, it causes excessive solidification shrinkage, which causes quality defects such as uneven solidification, deformation, and cracking of the slab.

(2) Next, in the case of the spray cooling method, there is a method of reducing the cooling water amount in the lower half to 1/2 to 1/4 of the upper half as disclosed in Japanese Utility Model Publication No. 1-60746. Proposed (see Figure 3). However, in the case of this system, when the amount of spray water in the lower half part is reduced, there is a problem that the spray distribution is disturbed or that the cooling of the lower spray is hindered by the water dripping from the upper part.

The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide a mold cooling device that can easily perform strong cooling on the upper side and weak cooling on the lower side.

[0007]

According to the present invention, as a mold cooling system, the upper part has a spray cooling structure, the lower part has a forced water flow cooling structure, and the lower forced water flow cooling part supplies the upper spray cooling part. It is characterized in that a cooling water passage is formed.

[0008]

The spray cooling mold of the present invention employs a spray cooling system for the upper part and a forced water flow cooling system for the lower part. The meniscus part with the highest heat load performs uniform strong cooling by spray cooling, and the heat flux from the slab decreases at the bottom of the mold where the shell thickness increases to a certain extent, so strong cooling is not necessary, and the slab quality is also good. We will also perform weak cooling by the forced water flow cooling method to improve the temperature. According to the present invention, even during high speed casting, ideal cooling of the meniscus portion with strong cooling and the lower portion with weak cooling can be efficiently performed with a small amount of cooling water.

[0009]

EXAMPLE FIG. 1 is a view showing an example of a spray cooling type mold of the present invention. The mold body 1 is a slab 2 to be cast
It is an open mold with a predetermined cross section according to the shape of, and is made of high thermal conductivity metal such as pure copper.

The cooling water supplied from the cooling water supply 11 is
After being stored in the lower cooling header 8, a forced water flow 6 parallel to the mold surface is formed from bottom to top in the cooling jacket 5 formed between the water channel forming plate 9 and the mold body 1,
Cool the lower part B of the mold. The cooling water that has cooled the lower part B of the mold is guided to the upper spray pipe 7, and spray water 4 is sprayed onto the upper part A of the mold by a spray nozzle 3 arranged at a predetermined position in the upper spray pipe 7 at a predetermined pitch. This upper part A is cooled by.

The cooling water obtained by cooling the upper part A of the mold with the spray water 4 is discharged from a drain pipe (not shown) connecting the lower surface of the upper spray chamber 10 and the lower drain chamber 14, and the cooling water drain 12
Be led to. Also. Part of the drainage water of the spray water 4 is the outer wall 1
5 is guided to a drainage chamber 14 below the mold through a gap 13 formed between the upper spray pipe 7 and the lower cooling header 8.

The upper part A of the mold having the spray cooling structure is
It is a position corresponding to the meniscus portion of the molten metal having a high heat load, and it is preferable to set it within a range of about 300 mm from the upper surface of the mold.

According to various studies and test results by the present inventors, when casting a slab size of 130 × 130 mm at a casting speed of 3 m / min, the cooling water amount of the mold is the same as the conventional forced water flow cooling system and spray cooling. In the case of the method, 150 each
While 0 l / min and 1200 l / min were required, in the case of the present invention, it is about 700 l / min, which is about 50% of the conventional value.
It was confirmed that the cooling water amount can be reduced, and that the quality problems such as uneven solidification, deformation, and cracking of the cast can be avoided by weakly cooling the lower part of the mold.

[0014]

As described above, according to the spray cooling type mold of the present invention, the following excellent effects can be obtained. (1) It can be effectively cooled with a small amount of cooling water even during high speed casting. (Can be cooled with about 50% of the cooling water of the conventional mold) (2) Uniform and strong cooling of the upper part and weak cooling of the lower part improve quality problems such as uneven solidification, deformation, and cracking of the slab. (3) In the conventional spray cooling mold, when the lower spray water is reduced and weak cooling is performed, there is a problem that sufficient cooling cannot be achieved due to water dripping from the upper spray and disturbance of the spray distribution. Disappeared.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a spray cooling type mold that is an embodiment of the present invention.

FIG. 2 shows a conventional forced water flow cooling mold.

FIG. 3 shows a conventional spray cooled mold.

[Explanation of symbols] 1 mold body 2 cast piece 3 spray nozzle 4 spray water 5 cooling jacket 6 forced water flow 7 upper spray pipe 8 lower cooling header 9 water channel forming plate 10 upper spray chamber 11 cooling water supply 12 cooling water drain 13 gap 14 lower Drainage chamber 15 Outer wall A Upper part of mold B Lower part of mold

Claims (1)

[Claims] 1. A mold of a continuous casting machine, wherein a cooling surface of the mold is divided into an upper part and a lower part, a top part has a spray cooling structure, and a lower part has a forced water flow cooling structure in which cooling water flows in parallel to the cooling surface. A spray cooling type mold for a continuous casting machine, characterized in that a cooling water flow path is configured so as to be supplied from the lower forced water flow cooling structure to the upper spray cooling structure.