JPS61283441A - Belt cooler for belt caster - Google Patents

Abstract

PURPOSE:To eliminate the deflection of belts in the transverse direction thereof and to prevent the middle recess deformation of an ingot by changing the pressure drop of the drain routes in the transverse direction of the belts between the central part and the end parts so that the flowing water film of cooling water is formed to a uniform thickness. CONSTITUTION:A belt caster is oppositely disposed with a pair of the cyclically movable metallic belts 1, 2 to constitute a casting space 3 to a convergent shape and is disposed with cooling pads 4, 5 apart from each other via a liquid passage space behind the belts 1, 2 to cool the belts. The hole size of the drain holes 6 of the pads 4, 5 is made larger from the end toward the central part to decrease the pressure drop of the drain route in the central part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a belt cooling device for a belt caster.
In particular, this proposal concerns the structure of a cooling device placed on the back side of the belt to support the long sides of the slab, especially regarding the drainage opening.

A belt caster is a continuous thin slab casting machine that directly produces thin slabs (so-called sheet bars, etc.) with a thickness of 50 m or less from molten steel, among other molten metals.

(Prior Art) A narrow type belt caster using a pair of moving metal belts with part of the running path facing each other is disclosed in Japanese Patent Application Laid-Open No. 59-92154. There is. The belt caster in this known technology is equipped with a cooling device called a "cooling pad" which has a large number of supply/drain ports opening facing the belt behind the head belt. The belt is cooled by forming a running water film between the belt and the belt.

However, between the cooling pad and the belt (liquid passage space),
Belt tension fluctuates due to belt centering, etc.
As a result, it becomes non-uniform in the width direction (the slab takes on the shape of a hollow). Therefore, there is a problem in that the thickness of the cooling liquid film flowing through the liquid passage space is not uniform, and as a result, the cooling in the belt width direction is also not uniform.

In order to solve such problems, the present applicant has previously filed a patent application filed in 1983-
No. 12151 showed a part of the solution, but it had not yet completely achieved its purpose, and improvements were still needed.

(Problems to be Solved by the Invention) In the prior art in this field, uniform support by the cooling water film in the width direction of the belt is inhibited, and the entire belt bends in an arched manner. Non-uniformity in the thickness of the slab in the width direction (s>) (s) Occurrence of casting due to leakage between the belt and the side plate (8) Sticking break that occurs between the belt and the side plate out, will inevitably occur.

(Means for Solving the Problems) The present invention solves the above-mentioned problems that need to be solved in the prior art by changing the drainage pressure loss (positive drainage distribution) corresponding to the belt width direction of the cooling pad. Even when the same flow rate of cooling water is supplied into the cooling pad, pressure is applied so that the fluid pressure distribution in the belt width direction can be adjusted to prevent bowing deformation of the belt. The basic idea was to raise the cooling pad to strengthen the contact with the side panel and prevent the occurrence of casting gaps, and proposed a cooling pad, that is, a cooling device, with a water inlet structure as shown in Figures 1 and 2. do.

For such a cooling device, the area ratio of the drain opening facing the belt (the ratio of the area of the drain opening to the pad surface) is
A belt constructed such that the ends are smaller than the center in the width direction of the belt is used. Although a slit-like form is conceivable as the form of the drain port, a hole-like form is preferably used.

As mentioned above, specific means for changing the drainage hole space factor include not providing a drainage slit or drainage hole near the end in the belt width direction, or reducing the width of the drainage slit or the diameter of the drainage hole from the end. Realized by

In the former case, when the width W of the cooling pad is 1,000 to 1,500 mm, the drain port at a position 20 to 200 u from the end should be blocked or not provided at all. In the latter case, the diameter of the drainage hole at the center is W, and the diameter from the end is W,
When ``e/We<1'' is selected, a drainage outlet space base is selected.

(Function) By changing the pressure drop in the drainage path in the belt width direction between the center and the ends, the thickness of the cooling water flow film becomes uniform, eliminating deflection in the belt and width direction. Prevents concave deformation of cast slabs, and also prevents boiling, casting, and breakouts.

The reason for the numerical limitation expressed as the space factor of the drain hole is that the pressure loss of the drain hole increases from the center of the width toward the ends, so that under the same flow rate, the pressure loss characteristic is as shown in FIG. 6. To increase the pressure at the belt end we/wo
<1 should be satisfied.

(Example) The device of the present invention will be explained using an example in which it is applied to a belt caster shown in FIG. The illustrated belt caster is of a narrowing type, and includes a pair of rotatable metal belts 1 and 2 that are disposed opposite each other to form a gap for holding molten steel and its solidified slab over a predetermined distance. A pair of fixed side plates (
(not shown) constitutes a casting space 8 with a tapered tip, and a cooling pad 4.5 is arranged on the back side of the metal belt 1, 2 with a liquid passage space in between for cooling the metal belts 1 and 2. This is what happens.

The cooling pad 4.5 has a hole shape as shown in FIGS. 1 and 2, but the one in FIG. This is an example in which the pressure loss of the drainage path is reduced, and the one shown in Fig. 2 eliminates the drainage hole 6 near the end, and only places it near the center, and furthermore, gradually increases toward the center.

This structure has a large diameter.

So, ■ As a conventional example? A cooling pad with 16 drainage holes of fiφ provided at a pitch of 20gm on one side in the belt width direction; ■ As an example of the present invention with the structure shown in Fig. 1, a cooling pad with 16 drainage holes of fiφ, 5.5 asφ, 6fi
φ, 6.5fiφ, 71111φ (and the remaining 11 holes up to the center are equal to 7fiφ, and a total of 16 holes are provided in 20 cod pitches.) ■ An example of the present invention with a structure corresponding to Fig. 2. 1005m from the end is non-porous, and there are a total of 12 7+m11 holes inside from that to the center.
A cooling pad with φ drainage holes opened at a pitch of 20m, 88! The belt deflection and water pressure distribution were investigated using The results are shown in Figure 4 (a) and (b). In addition, (a) and (b) in Fig. 5 are graphs showing a comparison between the present invention and the conventional example regarding the occurrence rate of cast overburden and the change in slab thickness, and the effect of the method of the present invention is remarkable. I understand that.

(Effects of the Invention) As explained above, according to the present invention, in addition to being able to reliably obtain slabs of a constant thickness, stable continuous casting is possible without cast casting, boiling, and breakouts caused by them. Operations can be carried out.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are both partial sectional views showing a part of the belt cooling device of the present invention, Fig. 8 is a route diagram of a belt caster employing the Stt of the present invention, Fig. ) is a graph showing the effect of the present invention on the amount of belt deflection and water pressure in comparison with the conventional example. Figures 5(a) and 5(b) are graphs showing the occurrence rate of casting and slabs showing the effects of the present invention. The graph of thickness change, Figure 6, is a graph showing the relationship between water supply hole diameter and water supply pressure loss. , 1.2
...Metal belt 8...Casting space 4.5...
Cooling pad 6... Drain hole No. 31! ! ('?)C%J S-

Claims (1)

[Claims] 1. At least one side of the part corresponding to the mold that faces each other is constructed of a metal belt that moves in synchronization with the drawing of the slab, and a cooling liquid supply and discharge function is provided behind the metal belt. In a belt cooling system for a belt caster that is equipped with a cooling system that cools slabs across the belt, the space factor of the drain opening facing the belt of the cooling system is determined by the belt width. A belt cooling device for a belt caster, characterized in that the end portion is smaller than the center portion.