JPH0811276B2 - Belt cooling structure and cooling method in twin belt type continuous casting apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a belt cooling structure of a twin-belt type continuous casting apparatus used for continuous casting of thin plates and a cooling method using the same cooling structure.

[Conventional technology]

2. Description of the Related Art A twin-belt type continuous casting apparatus has been conventionally used which forms a casting space in the wall thickness direction of a thin plate to be cast by a pair of belts and continuously feeds molten metal from a pouring nozzle. FIG. 7 shows an outline of the main part of this twin belt type continuous casting apparatus.

A pair of metal belts 50, 51 drive pulleys 52,
A casting space is formed between the belts 50 and 51 which are wound around the 53 and the pulley 54 and pass in a substantially vertical direction. The portion corresponding to the casting space receives the back surfaces of the belts 50 and 51 to suppress the deformation and cool the fin roll.
55 are arranged. Then, the pouring nozzle 56 is inserted into the upper end of the casting space, and the supplied molten metal becomes a thin cast piece A between the belts 50 and 51 and is discharged downstream.

Since the belts 50, 51 are heated by the molten metal from the pouring nozzle 56, a cooling nozzle 57 for injecting cooling water to cool the belt 50, 51 is provided as shown in FIG. The built-in structure of the cooling nozzle 57 is disclosed in, for example, Japanese Patent Laid-Open No. 60-152347.

A plurality of cooling nozzles 57 are arranged over the entire length in the width direction of the belts 50 and 51, and a plurality of cooling nozzles are also arranged in the casting direction.From each of them, cooling water is oblique to the running direction of the belts 50 and 51 as shown in the drawing. Spray cooling water onto the belt or the belt 5
A jet is applied vertically to the back surface of 0, 51 to cool it.

[Problems to be Solved by the Invention]

However, in the cooling nozzle 57 of the conventional structure, the jet end of the cooling water is located below the center of the pulley 54 as shown in FIG. Therefore, when the belt 50 is stopped, the range of the distance D between the position away from the peripheral surface of the pulley 54 and the position where the cooling water hits remains uncooled. Therefore, when the pouring nozzle 56 is inserted as shown by the alternate long and short dash line while the belt 50 is stopped, the pouring nozzle 56 is preheated, and the radiation of the pouring nozzle 56 heats the belt 50 in the uncooled portion. However, local thermal deformation occurs. A similar problem occurs in the left belt 51.

In this way, at the start of the belts 50, 51, the uncooled part is inserted by the pouring nozzle 56 and the belts 50, 51
Inevitable partial deformation of. Therefore, in addition to affecting the surface quality of the cast slab A, the belts 50 and 51 are frequently replaced, which is one of the causes of a decrease in the operating rate.

The problem to be solved in the present invention is to complete the cooling structure for eliminating the uncooled portion of the belt in the twin-belt type continuous casting apparatus and preventing its deformation.

[Means for solving the problem]

The cooling structure of the present invention cools a pair of belts that create a casting space in a substantially vertical direction around a pair of pulleys provided at intervals and a back surface of the belt that runs away from the peripheral surface of the pulleys. It has a cooling nozzle that injects water,
A twin-belt type continuous casting device for supplying molten metal by inserting a pouring nozzle into the upper end of the casting space, wherein the belt is separated from the peripheral surface of the pulley and a portion where cooling water from the cooling nozzle hits Between, and at least the period from the process of inserting the pouring nozzle into the casting space to the time before the belt is activated, the cooling water having jet holes for jetting the cooling water toward the back surface of the belt obliquely above. It is a belt cooling structure in a twin-belt type continuous casting apparatus including a water header.

Further, the belt cooling method of the present invention, from the process of inserting the jet of cooling water from the jet holes of the cooling water header into the upper end portion of the casting space of the pouring nozzle to running the belt. It is characterized in that it is performed for a period of time longer than the period.

[Action]

The cooling water from the cooling nozzle is jetted when the belt is running, and the belt is cooled uniformly by the running and receives the molten metal from the pouring nozzle and sends it downstream. On the other hand, before the belt is stopped and the casting is ready, the pouring nozzle from the tundish or the like is inserted into the upper end of the casting space formed between the belts. Since the pouring nozzle is preheated, the belt is heated by heat radiation when it is inserted. On the other hand, the cooling water is ejected from the ejection holes of the cooling water header continuously for a longer period of time from the insertion process of the pouring nozzle to the start of traveling of the belt. For this reason, the portion of the belt near the pouring nozzle that could not be cooled by the cooling nozzle is also cooled, and partial heating of the belt at the start of operation is suppressed. Therefore, the belt starts running without causing deformation or thermal strain, and thereafter, the belt operates while being continuously cooled by the cooling water from the cooling nozzle.

Further, when the moving speed of the belt is high, the passage time in the range D where the cooling water is not applied becomes short, and even if the cooling water is cut off, the belt does not deform or thermal strain due to heat radiation from the nozzle.

〔Example〕

FIG. 1 is a longitudinal sectional view showing the structure of the main part of the present invention, FIG. 2 is a sectional view taken along the line II of FIG. 1, and FIG. 3 is a longitudinal sectional view of the upper end of a twin belt type continuous casting apparatus. Is.

In FIG. 3, as described in the conventional example, a pair of metal belts 1 and 2 are wound around pulleys 3 and 4, and these belts 1 and 2 are respectively driven by drive pulleys (not shown) to form arrows in the drawing. Drive in the direction. Then, the pouring nozzle 5 is placed in a space formed in the vertical pass portion as a casting space.
Is plugged in. Also, below the pulleys 3 and 4, there are fin rolls 6 and 7 that receive the back surfaces of the belts 1 and 2 to adjust the casting space.
Is built in.

As shown in FIG. 1, a pipe 8a is provided around the pulleys 3 and 4 at a portion recessed from the peripheral surface thereof, and a cooling nozzle 8 is attached to the tip thereof. 4 and 5 are a partial front view and a perspective view showing the arrangement of the cooling nozzles 8 of the belt 1. The cooling nozzle 8 is arranged in a posture along the back surface of the belt 1 as shown in FIG. 1, and ejects cooling water from the lower end along the running direction of the belt 1. The same applies to the position and orientation of the cooling nozzle 8 with respect to the belt 2 on the right side.

Further, a cooling header 9 is installed at the back of the cooling nozzle 8 over substantially the entire length of the pulleys 3 and 4 in the axial direction. On the surface of the cooling header 9 that faces the back surface of the belts 1 and 2, ejection holes 9a are formed with the opening axis of the ejection hole 9a slightly upward in the horizontal direction.
These ejection holes 9a are provided between the adjacent cooling nozzles 8 as shown in FIG. 2, and are located higher than the ejection portion at the lower end of the cooling nozzle 8. An inlet 9b is provided at one end of the cooling header 9 as shown in FIG. 4, and cooling water having an appropriate water pressure is externally supplied from this inlet 9b so that the cooling water can be supplied from the jet holes 9a to the belts 1 and 2. Jet toward the back.

In the above structure, the belts 1, 2 by the cooling nozzle 8
The cooling of the belt is the same as the conventional structure, and the belt
While 1, 2 are running, continuously ejecting cooling water and belt
Cool 1,2.

Further, at the start of the operation, the belts 1 and 2 are cooled by the cooling header 8 in addition to the cooling nozzle 8. The ejection of the cooling water from the cooling header 9 is performed for a time period longer than the period from the insertion of the pouring nozzle 5 to the running of the belts 1 and 2 to start the continuous casting operation. This is because when the preheated pouring nozzle is inserted as shown in FIG. That is, only by the cooling nozzle 8, the belts 1 and 2 above the portion where the cooling water from the cooling nozzle 8 hits are heated by the pouring nozzle 5 as described in the conventional example, and the belts 1 and 2 are deformed. Was there. On the other hand, by cooling the back surface of the belts 1 and 2 on the pouring nozzle 5 side, which cannot be cooled by the cooling nozzle 8, by the cooling header 9, the deformation of the belts 1 and 2 at the start timing of the continuous casting operation can be prevented. You can Therefore, similar to the parts of the belts 1 and 2 cooled by the cooling nozzle 8,
The belts 1 and 2 are not deformed even when heat is radiated from the pouring nozzle 5.

Thus, even if the pouring nozzle 5 preheated while the belts 1 and 2 are stopped is inserted into the upper part of the casting space, the belts 1 and 2 are not deformed. Therefore, as compared with the conventional structure, the quality defect of the cast slab A that occurs each time the deformed portions of the belts 1 and 2 pass through the casting space is eliminated. Also belt
The 1 and 2 themselves also operate without distortion, improving their durability and reducing the frequency of replacement, thus improving the operating rate.

〔The invention's effect〕

(1) When inserting the pouring nozzle into the casting space between the belts, apart from the steady cooling by the cooling nozzle, the part heated by the pouring nozzle cools the belt located in the non-cooling part by the cooling water header. I am trying to do it. Therefore, the belt is not partially deformed by the heat from the pouring nozzle before the belt is run, and the surface quality of the cast slab to be cast can be improved.

(2) Not only the deformation of the belt itself but also the occurrence of thermal strain in the initial stage of operation can be suppressed, so that the durability of the belt is improved, the replacement frequency is lower than that of the conventional structure, and the operating rate is also improved.

(3) It is possible to prevent quality defects that have occurred every time the deformed portion caused by the above causes passes through the casting space.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of the main part of the present invention, FIG. 2 is a view taken along the line II of FIG. 1, and FIG. 3 is a vertical cross-section of the upper end of a twin-belt type continuous casting apparatus. FIG. 4 is a front view showing the arrangement of the cooling nozzles and the ejection holes of the cooling header, FIG. 5 is a schematic perspective view thereof, and FIG. 6 is a schematic view showing the cooling state of the belt by the cooling nozzles and the cooling header. FIG. 7 is a schematic view of a twin-belt type continuous casting apparatus, and FIG. 8 is a schematic view of a main part provided with only a conventional cooling nozzle. 1,2: Belt, 3,4: Pulley 5: Pouring nozzle, 6,7: Fin roll 8: Cooling nozzle, 8a: Piping 9: Cooling header, 9a: Jet hole 9b: Inlet A: Cast piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Tajima, Hirofumi Tajima 1 Nishinosu, Oita-shi, Oita Shin-Nippon Steel Co., Ltd. Inside the Oita Works (72) Junichi Yoneda 4-chome, Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima 22 Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Kanji Shozen 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (56) Reference JP-A-1-99754 (JP , A)

Claims (2)

[Claims] 1. A pair of belts that create a casting space in a substantially vertical direction by rotating a pair of pulleys provided at intervals, and cooling water on the back surface of the belt that runs away from the peripheral surface of the pulleys. A twin-belt type continuous casting device having a cooling nozzle for spraying and supplying a molten metal by inserting a pouring nozzle into an upper end portion of the casting space, wherein the belt is separated from the peripheral surface of the pulley and the cooling is performed. The cooling water is jetted toward the back surface of the belt diagonally above between the portion where the cooling water from the nozzle hits and at least during the period from the insertion process of the pouring nozzle into the casting space until the belt starts before. A cooling structure for a belt in a twin-belt type continuous casting apparatus, which is provided with a cooling water header having a jetting hole. 2. A pair of belts that create a casting idle in a substantially vertical direction by rotating a pair of pulleys provided at intervals, and cooling water on the back surface of the belt that runs away from the peripheral surface of the pulleys. With a cooling nozzle for injecting, when casting a thin slab with a twin-belt type continuous casting device that inserts a pouring nozzle into the upper end of the casting opening to supply molten metal,
A portion of the belt that is separated from the peripheral surface of the pulley and a portion that the cooling water from the cooling nozzle hits, and a cooling water header having ejection holes for ejecting the cooling water toward the back surface of the belt obliquely above, A method for cooling a belt in a twin-belt type continuous casting apparatus in which the cooling water is jetted from the jet port of the cooling water header at least during the period from the step of inserting the pouring nozzle to the upper end of the casting space of the pouring nozzle to the driving of driving the belt. .