JPH01218747A - Continuous casting apparatus for cast strip - Google Patents

Abstract

PURPOSE:To prevent the development of uneven thickness in a continuously cast strip by setting magnet to a pad for cooling the metallic belt, preventing deviation of the metallic belt and uniformly cooling the metallic metal with the fixed thickness of water film at the time of continuously casting the cast strip directly from the molten steel with belt caster system. CONSTITUTION:In the belt caster for continuously casting the cast strip A, such as sheet bar having <=50mm by pouring the molten steel from a pouring nozzle 4 in a vessel at gap between the metallic belts 1, 1 circulate-rotating with the plural guide rolls 3, cooling pad 5 for cooling the metallic belt 1 is arranged, and the cooling water is supplied from plural cooling water supplying hole 5a and the water film (a) between the metallic belts 1 is formed to cool the metallic belts 1 and the cooling water, which becomes high temp., is drained from the drainage hole 5b. By fitting plural magnets 5c to this cooling pad 5, the metallic belt 1 is attracted to the fixed position with attracting force of these magnets and the thickness of the water film (a) is always kept to the constant and the development of the uneven thickness in the continuously cast strip A caused by variation of cooling capacity by uneven thickness of the water film (a) is prevented.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a continuous casting device suitable for directly manufacturing thin cast slabs such as sheet bars with a thickness of 50 mm or less, particularly a cooling casting device for a so-called belt caster. This paper attempts to propose development results for improving structures.

(Prior Art) Various types of belt casters have been proposed for directly producing thin slabs such as sheet bars from molten steel. -32551 or JP-A-60-15234
Reference is made to the technique disclosed in Publication No. 7.

Now, this type of belt caster usually includes a pair of circulating metal belts forming a continuous casting mold, a fixed short side wall that is in close contact with the metal belts near their side edges, and a fixed short side wall that is in close contact with the metal belts near their side edges. It consists of main components such as a cooling device (cooling pad) that is installed on the back of the molten steel and forms a constantly flowing water film between them to indirectly cool the molten steel. Here, the above-mentioned cooling device is required to: 1) be able to secure a predetermined water film flow rate for cooling the slab, and 2> be able to secure a predetermined water pressure in the water film for holding the slab. However, in conventional belt casters, especially belt casters equipped with a straight type cooling device that is not convexly curved toward the molten steel side, a certain water film is formed in the area of the mold where the static pressure of the molten steel is low or the belt tension is low. It is difficult to secure the desired flow rate,
Therefore, the cooling capacity in that area decreases, leading to thermal deformation of the metal belt and resulting uneven thickness of the slab.

Life was inevitable.

“(Problem to be solved by the invention car) It is advantageous to maintain the thickness of the water film formed on the back side of the metal belt uniformly over the entire surface of the metal belt on which the cooling pad is arranged, thereby ensuring the desired cooling performance. It is an object of this invention to propose a continuous casting apparatus.

(Means for Solving the Problems) The present invention has a circulating metal belt that forms a continuous casting mold for thin slabs, and has a cooling water supply hole and a cooling water discharge hole. A continuous casting apparatus equipped with a cooling pad for forming a water film, characterized in that the cooling pad is provided with suction means for attracting a metal spool to maintain the water film at a constant thickness. It is a casting device.

FIG. 1 shows a side view of a continuous thin slab casting apparatus according to the present invention, and FIG. 2 shows a front view of the main part and an enlarged sectional view thereof. In the figure, number 1 is a circulating metal belt that forms a continuous casting mold for thin slab A, 2 is a short wall, 3 is a guide roll for circulating the metal belt, 4 is an injection nozzle, and 5 is on the back of metal belt 1. It is a cooling device (cooling pad) that forms a water film, and this cooling pad 5 has cooling water supply holes 5a.
A suction means (for example, a magnet) 5c is provided to attract the discharge hole 5b and the metal belt 1 to maintain the water film a at a constant thickness a, that is, to maintain a predetermined flow rate and pressure of the water film.

(Function) In this type of continuous casting equipment using a metal belt, the static pressure of the molten metal in the upper part of the continuous casting mold is particularly low, so it is necessary to maintain the desired water film flow rate and pressure in that area as shown in Figure 3. Therefore, it is difficult to maintain the thickness a of the water film formed between the cooling pad 5 and the metal belt 1 at a desired thickness when the metal belt 1 is pushed toward the molten metal side. As a result, the desired cooling capacity could not be secured, and uneven thickness of the slab due to thermal deformation of the metal belt 1 could be avoided. Therefore, in this invention, during casting work, the metal belt 1 in that area is always attracted to the side of the cooling pad 5 using an attraction means 5c such as a magnet provided on the cooling pad 5 to ensure a predetermined water film flow velocity and water pressure. The purpose is to maintain the thickness a of the water film uniformly in both the longitudinal and lateral directions. Note that it is desirable to adjust the arrangement position of the suction means 5c and the suction force of the suction means 5c as appropriate so that they are at appropriate positions and values.

(Example) A slab (AI) with a thickness of 30 mm and a width of 1000 mm was manufactured using the equipment shown in Figure 1 above under the following conditions to determine the life of the metal belt and the thickness accuracy of the slab. investigated.

The results are shown in Table 1. In addition, a magnet having a magnetic force equivalent to an attractive force of about 0.15 kg/cm2 was disposed at a position of the cooling pad 5, particularly in the area of the meniscus portion, in order to ensure a predetermined water film flow velocity and pressure.

Manufacturing conditions: ΔT (super heat): 38℃ Casting speed: 8m/min Water film thickness (
a): 0.5 mm Average water film flow velocity: 8 m/m1n = 5- Average water film internal pressure 0.15 kgf/cm2 Relative display with the value of the comparative example determined in Table 1 as 1.

As is clear from Table 1, the device according to the present invention was confirmed. Note that FIGS. 4(a) and 4(b) show changes in water film pressure and water film thickness in the casting direction.

Figure 4(a) shows the metal belt at the meniscus part (
This is an example of the case where the water film is attracted by a magnetic force having an attractive force equivalent to 1.15 kgf/cm2, and it is clear that the thickness of the water film can be maintained uniformly.

According to this invention, the flow rate and pressure of the water film formed between the metal belt and the cooling pad can be maintained uniformly over the entire surface to ensure sufficient cooling capacity. Multiple casting is now possible.

[Brief explanation of the drawing]

FIG. 1 is a side view of a continuous casting apparatus according to the present invention, FIG. 2 is a front view and a cross-sectional view of a cooling pad, and FIG. 3 is a cross-sectional view of a main part of a conventional example. (t+) is a graph showing changes in water film thickness and water film pressure in the casting direction. 1...Metal belt, 2...Fixed short side wall 3...Guide roll 4...Injection nozzle 5...Cooling device 5a...Cooling water supply hole 5b...Cooling water discharge hole 5c...Suction means (mIII [buy) and rumors also (wuI)''&/cum M-year-old

Claims (1)

[Claims] 1. Continuous casting equipment equipped with a circulating metal belt that forms a continuous casting mold for thin slabs, and a cooling pad that has cooling water supply and discharge holes and forms a water film on the back side of the metal belt. A continuous casting apparatus for thin slabs, characterized in that the cooling pad is provided with a suction means for attracting a metal belt to maintain a water film at a constant thickness.