JP4564765B2 - Thermal crown control device - Google Patents

Description

  The present invention relates to a thermal crown control device for controlling a thermal crown generated in a hearth roll incorporated in a heating zone and a cooling zone of a continuous annealing furnace.

  The continuous annealing furnace generally has a heating zone 13, a soaking zone 14, a slow cooling zone 15, a primary cooling zone 16, an overaging zone 17, a secondary cooling zone, as shown in the layout diagram of the continuous annealing furnace of FIG. 18 and a final cooling zone 20, and a steel strip 21 is conveyed and passed through these furnace bodies for heat treatment.

  A hearth roll 1 is adopted for transporting the steel strip 21, and the hearth roll 1 is arranged above and below each furnace body, and the steel strip 21 is wound around the hearth roll 1 by 180 ° or 90 ° and transported. . The steel strip 21 is preheated to room temperature or about 100 ° C. from the heating zone, enters the heating zone 13 and is heated to a predetermined temperature, and is soaked in the soaking zone 14 to the heated temperature. Is gradually cooled to 400 ° C. from the primary cooling zone 16 and sent to the overaging zone 17. In the aging zone 17, the steel strip 21 is aged, cooled by the secondary cooling zone 18, cooled to about 80 ° C. by the final cooling zone 20, and conveyed to the next process.

  In the heating zone 13, a furnace temperature higher than the heating temperature of the steel strip 21 is usually set in order to heat the steel strip 21 to a predetermined temperature. For example, if the heating temperature of the steel strip 21 is 800 ° C., the temperature is set to about 950 ° C., and the steel strip 21 is conveyed to the heating zone 13 having a furnace temperature set to 950 ° C. and heated to a predetermined temperature. . As described above, the temperature of the steel strip 21 entering the heating zone 13 is room temperature or about 100 ° C. Therefore, when the steel strip 21 is wound around the hearth roll 1 and conveyed, the heating zone 13 in particular. Since there is a difference between the surface temperature of the hearth roll 1 arranged on the entrance side of the steel plate and the temperature of the steel strip 21, when the steel strip 21 comes into contact with the hearth roll 1, the temperature difference causes thermal deformation of the steel strip 21, so-called heat buckle. appear. This heat buckle is likely to occur when the temperature difference between the hearth roll 1 and the steel strip 21 increases. Various techniques have been disclosed for preventing this heat buckle.

  For example, Patent Document 1 discloses a cooling or heating hearth roll around which a strip is wound, and a plurality of rows in the axial direction of the hearth roll, and a side of the strip opposite to the surface in contact with the roll. In a cooling / heating apparatus for a strip composed of nozzles for jetting cooling or heating gas toward a surface, a space formed between the side walls of a pair of nozzles is reduced and reflected by the strip There is disclosed a strip cooling / heating device provided with one or more combinations of nozzles in which a pair of nozzles are set at an angle such that the gas goes to the space.

  Further, in Patent Document 2, a spray that reduces the temperature difference along the axial direction of the roll by spraying a gas on a portion of the roll that supports the strip that does not contact the strip and spraying a gas on the non-contact portion of the strip. An apparatus for preventing thermal deformation of a belt support roll provided with means is disclosed.

  Further, in Patent Document 3, in a thermal crown control device provided with a coolant spraying device that sprays coolant onto the peripheral surface of a hearth roll of a continuous annealing furnace, the coolant spraying device is arranged to oppose the peripheral surface of the hearth roll. And selectively opening or closing the plurality of refrigerant outlets based on one or two or more slit-shaped or cylindrical strip refrigerant outlets and the meandering and / or narrowing amount of the metal strip supplied to the hearth roll. A thermal crown control device provided with an opening / closing device is disclosed.

In Patent Document 4, the inner wall of a hollow hearth roll is divided into a central part in the roll axis direction and both end parts in the roll axis direction, and a central cooling zone for injecting a cooling medium and cooling both ends. A hearth roll crown control device is disclosed in which a cooling zone is provided, and a central heating zone for heating the hearth roll divided into a central portion in the roll axial direction and both end portions in the roll axial direction and a double-sided heating zone are provided. .
JP 59-93839 A Japanese Patent Publication No. 6-2910 JP-A-11-315330 JP-A-8-176680

  The technique disclosed in Patent Document 1 is a technique for cooling or heating a steel strip wound around a roll. When cooling a steel strip, a cooling medium is jetted from a nozzle toward the steel strip to cool it. When heating the steel strip, the gas blown by the technique of injecting and heating the heating medium from the nozzle toward the steel strip is exhausted through the space between the nozzles. When the steel strip is wound around a hearth roll and continuously conveyed, there is a temperature difference between the surface where the steel strip is always in contact and the surface where the steel strip is not in contact. The temperature difference cannot be eliminated. For this reason, when a heating medium or a cooling medium is sprayed on a steel strip around which a hearth roll is wound, the thermal crown is further promoted, and a heat buckle is easily generated in the heating zone and a cooling buckle is likely to be generated in the cooling zone.

  Patent Document 2 is provided with a gas spraying means for spraying a gas facing a portion where the steel strip does not contact on the roll surface to reduce the temperature difference in the axial direction of the roll. Since it is installed from both sides, the gas spraying means has a one-sided structure. When it is installed in the heating zone or the cooling zone, it is deformed in strength and cannot exert the function of gas spraying. Further, there is no disclosure about the supply of the blowing gas, and assuming that an external medium is supplied into the furnace, the furnace pressure rises and hinders control of the furnace pressure.

  Also, the gas sprayed on the roll surface diffuses throughout the furnace. For example, when installed in a heating zone, the entire furnace is cooled by the diffusion of the cooling gas. Decreases.

  In Patent Document 3, which selectively opens and closes the refrigerant outlet by means of the metal meandering amount and the amount of squeezing, the nozzle opening and closing device is deformed by heat in a place where the temperature condition of the heating zone or cooling zone is severe, and the function is sufficient Can not be demonstrated.

  In the hearth roll of Patent Document 4 where a cooling zone and a heating zone are provided and controlled separately at the center and both ends, the hearth roll winds and conveys a steel strip, so the rotation balance becomes important. The rotational balance also changes due to changes in the thickness of the hearth roll. If the rotation balance of the hearth roll is poor, meandering occurs when the steel strip is conveyed. Therefore, it is preferable not to insert a nozzle or the like inside the hearth roll as much as possible.

  Therefore, the present invention provides a thermal crown control method and apparatus capable of preventing thermal deformation of a hearth roll and performing thermal crown control without reducing thermal efficiency.

The present invention includes a nozzle header having a nozzle divided into a plurality of hearth roll axial directions for blowing a refrigerant or a heat medium on a peripheral surface of a hearth roll incorporated in a continuous annealing furnace, and the axial temperature difference of the hearth roll by the blowing A thermal crown control device for reducing the number of nozzles in which the divided nozzles are arranged in a range of length L (mm) on both sides of the hearth length of the hearth roll , respectively, ) and the relationship between the minimum width B of the strip (mm) and the nozzle row of a length L (mm) is in the range of below 1 set, and the divided nozzle the hearth roll side of the opening length △ In the thermal crown control device in which L (mm) is in the range of the two formulas, the nozzle header is provided with the divided nozzles at the upper part and the coolant is supplied to the nozzles. Includes a pair of divided supply headers arranged to face each other and supplying a heat medium, and an exhaust header into which the sprayed refrigerant or heat medium is taken from an exhaust port between the supply headers End face seal plates are provided at both ends of the nozzle header, and side seal plates are provided in parallel along the axial direction of the hearth rolls between the nozzle rows arranged on both sides of the body length of the hearth rolls. A nozzle header is surrounded by an end face seal plate and a side surface seal plate, and the divided nozzles have a relationship between the length ΔL and the supply header side length ΔL1 (mm) as shown in the following three formulas to gas to the hearth roll surface. It is characterized by having a divergent shape in which the spraying is uniformly performed.
200 (mm) ≦ L ≦ (W−B) / 2 + 100 (mm) 1 set 50 (mm) ≦ ΔL ≦ 200 (mm) 2 sets ΔL> ΔL1 3 sets

  In the thermal crown control of the present invention, the nozzle is divided in the axial direction of the hearth roll, so that thermal deformation can be prevented and application to a severe temperature condition is also possible.

Further, the header portion of the control device so covered with the protective plate and the heat insulating material, it is possible to insulation from the outside, it is possible to prevent thermal deformation.

  The top and bottom surfaces of the nozzle are wider on the top surface of the nozzle than on the bottom surface, making it easier to attach to the header and expanding toward the top of the nozzle, so spraying evenly on the hearth roll I can do it.

  Further, the thermal crown control device of the present invention integrally incorporates an exhaust header for exhausting the refrigerant or the heat medium blown from the nozzle and the nozzle space, and the refrigerant or the heat medium blown also from the gap between the divided nozzles. Because it is designed to take in air, most of the refrigerant or heat medium sprayed on the hearth roll surface can be recovered without diffusing into the furnace, and thermal crown control can be performed without reducing thermal efficiency. It becomes.

  FIG. 1 is a schematic layout diagram of a thermal crown control device according to the present invention, showing an example in which the thermal crown control device is arranged above the heating zone of a continuous annealing furnace. A hearth roll 1 is pivotally supported on a bearing 22 fixed to the heating zone 13, and a thermal crown control device 2 is supported by a support 25 below the hearth roll 1.

  The thermal crown control device 2 includes a nozzle header 3 having a nozzle 4 for spraying a refrigerant or a heat medium as a heat exchange medium on the peripheral surface of the hearth roll 1, and the nozzle header 3 is connected to a supply pipe 23 and an exhaust pipe 24. The exhausted heat exchange medium is heat-exchanged by the heat exchanger 29 and supplied to the nozzle header 3 by the blower 30. The thermal crown control device of the present invention is particularly suitable for the hearth roll 1 illustrated by the black circles in FIG.

  FIG. 2 is a perspective view showing an embodiment of the thermal crown control device of the present invention. The nozzle header 3 is composed of a pair of supply headers 5 and exhaust headers 7 facing each other with a gap therebetween, and a plurality of nozzles 4 are formed on both sides in the longitudinal direction of each supply header 5. It is aired.

  The exhaust header 7 is blown out of the exhaust port 6 between the opposing supply headers 5 and is exhausted from the exhaust pipe 24. End seal plates 26 are provided at both ends of the nozzle header 3, and side seal plates 27 are provided between the central nozzles 4 of the nozzle 4, and are surrounded by the end seal plates 26 and the side seal plates 27. The blowing gas is efficiently collected in the exhaust header 7.

  FIG. 3A is a perspective view showing another embodiment of the thermal crown control device of the present invention, and FIG. 3B is a longitudinal sectional view. In the present embodiment, the plurality of nozzles 4 provided on both sides in the longitudinal direction of each supply header 5 are divided into two groups, the outer side and the inner side, and the supply header is made independent for each group. Air is supplied to the supply header 5a through the supply pipe 23a, and the group of the inner nozzles 4b is supplied to the supply header 5b through the supply pipe 23b, and the use range of the nozzles is switched according to the plate width of the steel plate.

  FIG. 4 shows an outline of the nozzle, (a) is a front view, (b) is a plan view, and (c) is a side view. The supply header 5 and the exhaust header 7 are provided in a heat insulating material 8 covered with a protective plate 9. The nozzle 4 provided at the upper part of the supply header 5 is formed so as to widen upward, and gas is sprayed evenly from the rectangular nozzle opening 10 onto the surface of the hearth roll 1 around which the steel strip 21 is wound. The exhaust gas 12 is taken in from the exhaust port 6 of the exhaust header 7.

  FIG. 5A is an explanatory diagram of the relationship between the nozzle length, steel strip width, and roll cylinder length of the thermal control device, and FIG. 5B is an explanation of the thermal crown control device in which the nozzles shown in FIG. 3 are grouped. FIG.

  In FIG. 5A, a plurality of nozzles 4 divided into a range of L length are arranged on both sides of the hearth roll 1 with respect to the body length W of the hearth roll 1 below the hearth roll 1. The division length ΔL is 50 mm or more and 200 mm or less. If it is 50 mm or less, the number of divisions increases, and the nozzle 4 base cannot be fixed to the supply header 5, and if it is 200 mm or more, thermal deformation occurs and the medium cannot be evenly ejected from the nozzle 4. For example, the minimum width B of the steel strip 21 is 900 mm, the nozzle length L is 600 mm on both sides with respect to the barrel length W = 2000 mm, and each divided nozzle length ΔL = 200 mm is employed.

  Thus, by satisfying 200 ≦ L ≦ (W−B) / 2 + 100 (1 formula) and 50 ≦ ΔL ≦ 200 (2 formula), a thermal crown control device having a nozzle with little thermal deformation is provided. can do.

  In the formula (1), 200 ≦ L is set because the steel crown edge has a walk of about ± 100 mm during conveyance, and therefore it is necessary to control the thermal crown in the range of 200 mm. This is because when crown control is performed, if L is less than 200 mm, there is no effect of crown control. Further, L ≦ (W−B) / 2 + 100 is necessary to cover the maximum width to the minimum width, and a width larger than this is meaningless.

  Further, from the above results, as shown in FIGS. 4A and 4B, when the length ΔL = 200 mm is adopted for the upper portion of the nozzle, the nozzle length of the nozzle base (fixed portion with the header 5) is used. ΔL1 = 180 mm. In this way, by setting ΔL> ΔL1, the gas expands toward the hearth roll in a divergent shape, so that the gas can be evenly sprayed onto the hearth roll surface.

  As shown in FIG. 4C, the gas 11 injected from the nozzle 4 collides with the surface of the hearth roll 1 to cool the surface temperature of the hearth roll 1, and the cooled gas 12 is an exhaust port between the nozzles. 6 is discharged from the exhaust header 7. The discharged gas gathers at the exhaust header 24 communicating with the outside of the furnace, is cooled by the heat exchanger 29, and is blown again from the in-furnace supply header 5 to the hearth roll 1 through the supply header 23.

  Further, since the divided nozzle 4 is set to the opening length ΔL on the hearth roll 1 side and the length ΔL1 on the supply header 5 side in a relationship of ΔL> ΔL1, the nozzles shown in FIG. Since the opening 4a exists, the exhaust header 7 is recovered through this opening.

  In FIG. 5B, in the case of the steel strip 21a having a large width, only the supply header 5a is used without using the supply header 5b, and in the case of the steel strip 21b having a small width, the supply header 5a is not used. By using only the header 5b and spraying only the necessary range according to the width of the steel strip, the amount of refrigerant or heat medium sprayed can be reduced, and the reduction in energy intensity can be further reduced.

It is a schematic layout of the thermal crown control device of the present invention. It is a perspective view which shows one Example of the thermal crown control apparatus of this invention. (A) is a perspective view which shows one Example of the thermal crown control apparatus of this invention, (b) is a longitudinal cross-sectional view. (A) is a perspective view which shows one Example of the thermal crown control apparatus of this invention, (b) is a longitudinal cross-sectional view. (A) is explanatory drawing of the relationship with the nozzle length of a thermal control apparatus, steel strip width, and roll trunk | drum length, (b) is explanatory drawing about the thermal crown control apparatus which grouped the book slip shown in FIG. . It is a layout diagram of a continuous annealing furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hearth roll 2 Thermal crown control apparatus 3 Nozzle header 4 Nozzle 4a Nozzle opening 5 Supply header 6 Exhaust port 7 Exhaust header 8 Thermal insulation material 9 Protection plate 10 Nozzle opening part 11 Discharge gas 12 Exhaust gas 13 Heating zone 14 Soaking zone 15 Slow cooling zone 16 Primary cooling zone 17 Over-aging zone 18 Secondary cooling zone 19 Sealing device 20 Final cooling zone 21 Steel strip 22 Bearing 23 Supply header 24 Exhaust header 25 Support 26 End seal plate 27 Side seal plate 29 Heat exchanger 30 Blower

Claims (1)

A thermal apparatus comprising a nozzle header having a nozzle divided into a plurality of hearth roll axial directions for blowing a refrigerant or a heat medium on a peripheral surface of a hearth roll incorporated in a continuous annealing furnace, and reducing the axial temperature difference of the hearth roll by the blowing. A crown control device,
A nozzle row in which the divided nozzles are arranged in a range of length L (mm) on both sides of the hearth length of the hearth roll is arranged, respectively, and the hearth length W (mm) of the hearth roll and the minimum width B (mm) of the steel strip wherein the relationship between the length of the nozzle row L (mm) is in the range of below 1 set, and the divided nozzles and the hearth rolls side of the opening length △ L a (mm) in the range of two equations and In the thermal crown control device
The nozzle header is provided with the divided nozzles at the top and supplies a refrigerant or a heat medium to the nozzles, a pair of the divided supply headers arranged to face each other at an interval, and the sprayed refrigerant or An exhaust header in which a heat medium is taken from an exhaust port between the supply headers,
End nozzle seal plates are provided at both ends of the nozzle header, and a side seal plate is provided in parallel along the axial direction of the hearth roll between the nozzle rows arranged on both sides of the barrel length of the hearth roll. The header is surrounded by an end face seal plate and a side seal plate,
The divided nozzles have a relationship of the length ΔL and the length ΔL1 (mm) on the supply header side as shown in the following three formulas so as to spread the gas evenly on the surface of the hearth roll. Thermal crown control device.
200 (mm) ≦ L ≦ (W−B) / 2 + 100 (mm) 1 set 50 (mm) ≦ ΔL ≦ 200 (mm) 2 sets ΔL> ΔL1 3 sets

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