KR20000039451A - Roll cooler of continuous casting machine using heat pipe - Google Patents

Abstract

PURPOSE: A roll cooler of a continuous casting machine is provided to obtain a uniform distribution of temperature in a circumferential direction of a roll by equipping the roll cooler using a heat pipe in the roll. CONSTITUTION: A cooler(8) contains a tubular body(10) extended in a ring shape and maintained an inner space in a vacuum state, an operating fluid(14) accepted inside the body(10) and a porous body(11) arranged via an inner circumference of the body(10). When a gradient of temperature is existed inside the body(10), the operating fluid(14) inside the body(10) is evaporated in a high temperature portion(H) near a mold piece. Because a latent heat of the evaporated gas is large, the gas is condensed by quickly moving in a low temperature portion(L) in a center of roll via the porous body(11) with a small difference of temperature. The operating fluid(14) ventilated the latent heat and liquefied during condensing in the low temperature portion(L) is returned to the high temperature portion(H) through the porous body(11) operated a capillary principle. Thereby a distribution of surface temperature in a circumferential direction of roll(9) is uniformed by performing a heat exchange with a higher heat conductivity than a copper.

Description

Roll Cooling System of Continuous Casting Machine Using Heat Pipe

The present invention relates to a cooling apparatus for a roll used in a cooling stand of a continuous casting machine. In particular, by using a roll cooling means using a heat pipe on the roll, a more uniform temperature distribution can be obtained in the circumferential direction of the roll. It relates to a roll cooling apparatus of a continuous casting machine configured

Continuous casting machine related to the present invention is a ladle (2), the molten steel (1) wound as shown in Figure 1, tundish (3), cast slab to function to separate the molten steel storage and inclusion floating between the ladle (2) and the mold (4) And a secondary cooling stand (5) which is combined into a plurality of segments and a mold (4) which solidifies the mold into the required shape and size. Here, the secondary cooling stand 5 is cooled by a nozzle and pressed by a roll so that the cast metal passing through the cooling stand 5 maintains a solidified shell of a constant thickness at an arbitrary position.

The rolls used in the secondary cooling stand 5 are composed of driving rolls responsible for drawing the slabs and guide rolls for bulging the slabs and guiding the slabs in a predetermined casting direction. Because of its contact with the cast iron, it is susceptible to deformation due to thermal load, and the thermal deformation of such rolls has a great negative effect on the cast quality.

Conventionally, in order to suppress thermal deformation of such cooling stand rolls, cooling water passages 6a, 6b, 6c are formed in various forms inside the rolls 9a, 9b, 9c as shown in the example of FIG. The roll was cooled using a method of circulating the coolant through the coolant passage. However, the roll cooling method only slightly lowers the maximum temperature of the roll surface, and in particular, the roll surface temperature is very high (about 1,000 ° C. or more). Due to severe temperature gradient in the circumferential direction, there is a problem that the repeated fatigue heat load cannot be removed, and thus cracks frequently occur on the roll surface, which shortens the roll life, and thus frequently causes defects in cast iron. There was a problem.

Therefore, the present invention has been studied to solve the conventional problems as described above, the roll temperature can be slightly reduced when the roll cooling by forced circulation of the cooling water as in the prior art, but the dominant effect on the roll life It is an object of the present invention to provide a roll cooling apparatus of a continuous casting machine, which is improved to solve the problem that the heat load of the repetitive fatigue known to remain as it is.

1 is a configuration diagram of a continuous casting machine according to the present invention;

2 is a cross-sectional view of rolls provided with a conventional roll cooling apparatus;

Figure 3a is a front sectional view of a roll with a heat pipe installed according to the present invention,

Figure 3b is a side cross-sectional view of the roll shown in Figure 3a,

Figure 4 is a side cross-sectional view showing a detailed configuration and operation principle of the roll cooling apparatus according to the present invention;

Explanation of symbols on the main parts of the drawings

1: molten steel 2: ladle 3: tundish

4: mold 5: secondary cooling zone segment 8: cooling device

9: roll 10: body 11: porous body

14: working fluid

In order to achieve the above object, the present invention provides a roll cooling apparatus for a continuous casting machine, comprising a plurality of heat pipes arranged along the circumferential direction of the roll in the roll cooling apparatus of the continuous casting machine. to provide.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3A and 3B show, respectively, a cross sectional and side cross sectional view of a continuous casting machine cooling stand roll 9 equipped with a cooling device composed of a heat pipe therein according to the present invention.

A single cooling tube 6 penetrates the center of the roll 9, and a cooling device 8 composed of a plurality of heat pipes made of closed tubes is formed around the roll 9 through which the cooling tube 6 is installed. Install along the circumferential direction of.

Fig. 4 shows the detailed configuration and operating principle of the cooling device 8 installed inside the cooling stand roll 9 of the continuous casting machine according to the present invention. The cooling device (8) is formed in a tubular body (10) extending in an annular shape and having an internal space maintained in a vacuum state, a working fluid (14) housed in the body (10), and the body (10) of It is set as the structure containing the porous body 11 arrange | positioned along the inner peripheral surface. As such, when a temperature gradient exists in the body 10 in a state in which the working fluid is sealed in the tubular body 10 in which the inside is kept in a vacuum state, the high temperature portion of the working fluid 14 in the body 10 is close to the cast steel side. Since the latent heat of the evaporated gas at (H) is considerably large, the evaporation gas moves very rapidly along the porous body 11 to the low temperature part L toward the center of the roll and condenses even at a small temperature difference. The latent heat liquefied while condensing at the low temperature portion (L) and the liquefied working fluid 14 is returned to the high temperature portion (H) through the porous body 11 on which the capillary principle works. When this action is repeatedly performed, heat exchange occurs naturally with heat conductivity up to several hundred times as compared with copper, so that the surface temperature distribution in the circumferential direction of the roll 9 is uniform.

In a preferred embodiment, the cooling device 8 is positioned in a direction perpendicular to the longitudinal direction of the roll 9 at a position of a certain depth on the surface of the roll 9, the working fluid 14 is 20 to 400 It operates in the temperature range of ℃, the body 10 is maintained inside a vacuum of about 10 ^-4 torr.

By installing a plurality of the cooling means 8 at regular intervals along the longitudinal direction of the roll 9, as in the case of Figure 3a to maximize the cooling effect in consideration of the temperature gradient in the roll circumferential direction.

According to the present invention, the heat pipe type cooling device 8 is installed inside the roll 9 in the circumferential direction of the roll to achieve a uniform temperature distribution in the circumferential direction of the roll. There is a characteristic that can reduce the roll maintenance cost by improving and extending the roll life.

Claims (1)

An apparatus for cooling the cooling stand roll (9) of a continuous casting machine, comprising: a tubular body (10) sealed in an annular shape and kept in a vacuum state, a working fluid (14) housed in the body (10), Roll cooling apparatus of a continuous casting machine using a heat pipe, characterized in that the cooling device (8) consisting of the porous body (11) arranged along the inner circumferential surface of the body (10) installed in the roll circumferential direction.