JPH03170619A - Device for cooling in roll in continuous annealing furnace - Google Patents

Abstract

PURPOSE:To suppress the occurrence of a thermal crown in a cooling roll using a refrigerant by pressing heat escape rolls cooled with a refrigerant against the noncontact part of the circumference of the cooling roll when a sheet is cooled with the cooling roll by contact with the roll. CONSTITUTION:When a sheet 1 is cooled with a cooling roll 3 internally cooled with a refrigerant by winding contact with the roll 3 in a cooling zone in a continuous annealing furnace, heat escape rolls 4 internally cooled with a refrigerant are pressed against the noncontact part of the circumference of the roll 3 to cool the roll 3. An ununiform thermal crown in the roll 3 is made uniform and the sheet 1 is uniformly cooled in the transverse direction.

Description

[Detailed description of the invention] Industrial application field> The present invention relates to a roll cooling device installed in a cooling zone of a continuous annealing furnace. <Prior art> The roll cooling method, which is often used in the cooling zone of continuous annealing furnaces for copper strips, etc., has the following advantages: it has a large heat transfer coefficient, allows rapid cooling, is easy to control temperature, is not oxidized by cooling, and has low running costs. There are advantages. In general, this roll cooling method cools the plate by wrapping the plate around a roll whose interior is cooled with a refrigerant such as water, and bringing the plate into close contact with the roll surface. In this roll cooling, it is important to prevent temperature differences from occurring in the width direction of the sheet, and Japanese Patent Publication No. 62-48732 describes the structure of the cooling roll, how to flow the coolant, etc.
Special Publication No. 62-61092, Special Publication No. 63-8l74
Publication No. 14052, Special Publication No. 14052, Special Publication No. 14052, Special Publication No. 1981-
Various proposals have been made, as shown in Japanese Patent Publication No. 56297, Japanese Patent Publication No. 45288/1988, Japanese Patent Publication No. 4050/1986, etc. However, since the plate temperature is higher than the roll temperature, it is inevitable that the roll surface temperature at the temporary contact area will rise and a thermal crown will occur on the roll. If the thermal crown is uniform in the width direction of the sheet, there will be no problem, but if it is uneven, there will be parts that do not make temporary contact with the roll.
That area is not cooled and there is a temperature difference across the board. Once uneven heat is generated in the roll, the heated part expands and rises, making contact with the strip under strong pressure, and the temperature gradually increases. As a result, the shape of the plate after cooling deteriorated, causing meandering and also causing material defects. FIG. 1 schematically shows the cross section of the part where the plate 1 is in contact with the cooling roll 3, and shows the thermal crowns 2-1 and 2.
-2 has occurred, and if the peaks are locally high or the degree of non-uniformity is large, the above-mentioned problems will occur. Problems to be Solved by the Invention The present invention aims to propose a roll cooling device that reduces the uneven thermal crown that occurs on the cooling roll of a continuous annealing furnace. Means for Solving the Problems> The present invention provides a roll cooling device that cools a cooling roll whose inside is cooled by a refrigerant in a cooling zone of a continuous annealing furnace by wrapping a plate in contact with the cooling roll. This is a roll cooling device for a continuous annealing furnace, characterized in that a heat extraction roll whose inside is cooled by a refrigerant is pressed against a portion of the cooling roll that does not come into contact with the temporary part of the cooling roll, thereby reducing the thermal crown of the cooling roll. <Operation> An embodiment of the present invention is shown in Fig. 2. FIG. 2 is a side view, in which the heat removal roll 4 is pressed against the opposite side of the cooling roll 3 where the plate 1 is wound. The insides of the cooling roll 3 and heat removal roll 4 are cooled with water or the like. The contact position between the cooling roll 3 and the heat extraction roll 4 is determined by the heat crown of the cooling roll 3. That is, the portion of the cooling roll 3 having a large heat crown in the width direction contacts the heat removal roll 4. Since the temperature of the heat removal roll surface is lower than that of the cooling roll, the surface of the cooling roll that comes into contact with the heat removal roll will be cooled there. Therefore, the temperature of the thermal crown of the cooling roll 3 in contact with the heat extraction roll 4 decreases, and the thermal crown also becomes smaller. FIG. 3 is an explanatory diagram showing this situation.

In this way, the uneven thermal crown 2 of the cooling roll 3
By pressing the heat removal roll 4, only the large part of the thermal crown 2 is cooled and becomes smaller, and finally the cooling roll 3 has a uniform thermal crown. In the present invention, the method of supporting the heat removal rolls is not specified, but it is preferable to use a gimbal mechanism with two or four bare rolls because stable contact can be achieved. Note that a technique for cooling a heated roll by pressing it against another cooled roll was disclosed in Japanese Patent Application Laid-Open No. 60-18.
4406, but this patent merely cools heated solid rolls such as rolling rolls, and has nothing to do with cooling rolls with hollow parts inside, much less heat crowns. This technique is not intended for correction and is different from the present invention. Next, we will discuss an example in which the roll cooling device of the present invention is actually applied. As in the past, the transport cooling roll is 2400 L x 1500 amφ and has a shell thickness of 40 mm and has a water-cooled interior.
When a strip with a width of 1000 to 1200 m was cooled through the plate at a temperature of 460°C, the heat crown amount shown in Figure 1 was 420 Irm, and the difference between the left and right heat crowns, that is, (r1 rg) was 45-. On the other hand, this cooling roll is equipped with a heat removal roll of the present invention, size 2.
By pressing two 400L x 350mφ internal water-cooled units, the height difference between the left and right peaks in the heat crown was reduced from 45pm to less than 15μs. <Effects of the Invention> By adopting the device of the present invention, a uniform thermal crown is always formed on the cooling roll, and uniform cooling in the temporary width direction becomes possible. Therefore, the temperature difference in the width direction of the plate is reduced,
The plate shape became stable after cooling. This effect improved furnace productivity and board quality.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the state of contact between the cooling roll and the plate, Figure 2
The figure is a side view showing one embodiment of the present invention, and FIG. 3 is an explanatory view showing the contact state between the cooling roll and the heat extraction roll. 1... Plate, 2... Thermal crown, 3... Cooling roll, 4... Heat extraction roll.

Claims (1)

[Claims] In the cooling zone of a continuous annealing furnace, in a roll cooling device in which a plate is wrapped around and brought into contact with a cooling roll whose inside is cooled by a refrigerant, the inside is cooled by a refrigerant at a portion of the circumference of the cooling roll that does not come into contact with the plate. 1. A roll cooling device for a continuous annealing furnace, characterized in that a heat removal roll is pressed to reduce thermal crown of the cooling roll.