JPH05209231A - Strip cooling device for continuous annealing - Google Patents

Abstract

PURPOSE:To stably manufacture a produce where the temperature profile in the direction of the strip width is improved and the quality is uniform is strip cooling device, where cooling rolls are employed in a continuous annealing equipment. CONSTITUTION:A cooling roll 1 consists of a single roll of a large diameter, and movable deflector rolls 2a and 2b which move along the circumference of the roll 1 around this roll 1 which can adjust the contact angle between the roll 1 and a strip X, are provided, and at the same time, bridle rolls 3a and 3b are arranged on the entry side and the exit side of the cooling roll 1, respectively. Gas jet nozzles 4a, and 4b are provided between the cooling roll 1 and the bridle roll 3b, and a sheet temperature meter 5 which is capable of measuring the temperature profile in the width direction of the strip X is provided on the bridle roll 3b side, and the measured value is inputted to a control and arithmetic device 6. This control and arithmetic device 6 provides a command to the gas jet nozzles 4a, 4b on the basis of the input of the measured value so that the sheet temperature distribution in the width direction of the strip X may be uniform, performing the adjustment of the cooling in the width direction of these strips.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip cooling device for quenching strips by cooling rolls for continuous annealing.

[0002]

2. Description of the Related Art In a strip roll cooling method carried out in a continuous annealing equipment, a cooling roll having a spiral groove inside and a coolant such as cooling water passing through the groove is usually used. ..

FIG. 11 shows an example of the structure of a quenching equipment for continuous annealing of strips X using a plurality of cooling rolls 1a to 1e. The quenching equipment has a structure in which each of the cooling rolls 1a to 1e can move in the direction orthogonal to the strip pass line, and the contact area with the strip X is changed by these movements to obtain a predetermined temperature drop amount. You can do it.

[0004]

However, in the above-described roll cooling equipment, uneven cooling is apt to occur such that the temperature of the strip edge portion becomes high, and the temperature distribution in the strip width direction is non-uniform. When the temperature distribution in the plate width direction becomes non-uniform, the shape of the strip X is deformed, and meandering or throttling occurs in the subsequent overaging furnace, which significantly impairs the stable operation of the furnace. .. In addition, when such a non-uniform temperature distribution occurs, the important aging index among the materials of general cold-rolled steel sheet is partially inferior at the edge portion, etc., and there is a problem that only products with uneven material in the width direction can be manufactured. Was there.

The present invention was devised in view of the above problems of the prior art. In a cooling device for performing roll cooling for continuous strip annealing, the temperature profile in the strip width direction is improved and a uniform temperature profile is obtained. The purpose is to obtain a stable product of the material.

[0006]

Therefore, in the strip annealing apparatus for continuous annealing of the present invention, at least one of the one to a plurality of cooling rolls has a large diameter, and the large cooling roll is surrounded by In addition to having two or more movable deflector rolls that can be moved around the roll to adjust the contact angle between the roll and the strip, bridle rolls are arranged at the inlet side and the outlet side of the cooling roll, and the cooling roll outlet is provided. A gas jet nozzle that can adjust the cooling amount in the strip width direction is provided between the outlet side and the outlet side bridle roll, and a plate thermometer that can measure the temperature profile in the strip width direction is installed on the outlet side bridle roll side. Based on the above, the basic feature is that a control arithmetic unit for adjusting the strip width direction cooling amount of the gas jet nozzle is provided.

The above-mentioned structure is made based on the clarification of the cause of the problem in the prior art by the present inventors. The clarified cause will be described in detail below.

It is estimated that the occurrence of cooling unevenness in the conventional structure is caused mainly by the low contact surface pressure between the cooling roll and the strip. In particular, as shown in FIG. 4, by winding the strip X around a cooling roll to give a curvature R, the roll contact side of the strip X receives a tensile stress in the roll axial direction, and the opposite side receives a compressive stress. As a result, as shown in FIG. 5, a portion H that does not completely contact the cooling roll 1 is generated at the edge portion of the strip X. As shown in FIG. 6, the edge lift amount H tends to increase when the strip tension of the cooling roll portion is small. If the radius of the cooling roll, that is, the curvature R of the strip 1 is small, the edge lift amount H also increases in this case as shown in FIG. Due to the above phenomenon, the strip edge portion has a high temperature distribution as shown in FIG. 8 and the aging index is inferior at the edge portion as shown in FIG. Was produced, and the meandering and throttling in the furnace due to the collapse of the strip shape occurred, resulting in the inability to operate stably.

The above-mentioned problem is to install a tension applying device such as a bridle roll that can apply a tension to the strip before and after the cooling roll, and to cool the strips that have been in contact with it by providing a plurality of tension applying devices. Since all or most of them are configured by one large-diameter cooling roll having a contact area equivalent to these contact areas, the edge lift amount can be significantly reduced. on the other hand,
Since it is not possible to expect complete cooling of the edge just by adding tension to the strip and increasing the diameter of the cooling roll, a gas jet nozzle capable of adjusting the cooling amount in the strip width direction is arranged at the rear stage of the cooling roll group, In addition, the strip width direction temperature profile is measured by the plate thermometer installed on the outlet side bridle roll side, and the measured signal is sent to the control arithmetic unit to control the edge cooling amount, so that a uniform temperature distribution is output from the cooling device. So that you can get on the side.

On the other hand, as shown in FIG. 10 (a), when the cooling amount of the roll that comes in contact with the strip later is larger than the cooling amount of the roll that comes earlier in the sequence, as shown in FIG. ) The high temperature part of the edge extends to the central part of the plate width, the cooling load at the gas jet nozzle installed on the exit side of the cooling roll group also becomes large, and the part with poor aging is the central part of the plate width. I will enter the department. In the present invention, the cooling rolls that come into contact with the strips first are formed of large-diameter cooling rolls having the same contact area as that of a plurality of cooling rolls (in some cases, one cooling roll has a large diameter). In addition, since the contact area is adjusted by the movable deflector roll to uniformly cool it over a wide contact area, it is possible to prevent the high temperature portion of the edge from reaching the central portion of the plate width.

In order to improve the cooling capacity of the edge cooling gas jet nozzle, the blowing gas is H ₂ 40 to 90%,
It is recommended to use N _{2 in} the range of 10 to 60%.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing a horizontal roll cooling device in a strip continuous annealing equipment in a state in which the structure of one embodiment of the present invention is applied.

The strip X that has been heated and soaked and then gradually cooled enters the roll cooling device and has a large diameter cooling roll.
It will be cooled in 1 and sent to the next overaging treatment. Among these, in the present roll cooling device, a plate thermometer 50 for measuring the inlet plate temperature is provided in front of the entrance side bridle roll 3a described later, and the measured value is input to the control calculation device 6 described later, and the control calculation device At 6, the roll cooling amount is calculated from the inlet plate temperature, the target outlet plate temperature that has been input in advance, and the strip size and line speed. Based on this calculation, the control calculation device 6 gives commands to the moving devices 20a and 20b of the movable deflector rolls 2a and 2b that move around the cooling roll 1 around the roll 1, respectively, and the winding amount of this roll, that is, The amount of roll cooling can be adjusted.

Further, in this embodiment, the bridle rolls 3a and 3b are arranged on the inlet side and the outlet side of the cooling roll 1 and the cooling roll 1 (correctly, the fixed deflector roll 20).
And gas jet nozzle 4 between the exit bridle roll 3b
a and 4b are provided, and a strip thermometer 5 consisting of a multiple reflection thermometer and a radiation thermometer capable of measuring the temperature profile in the strip width direction is provided on the exit side bridle roll 3b side, and the outlet strip temperature profile is further controlled. Inputting to the arithmetic unit 6.
In this control arithmetic unit 6, in addition to adjusting the roll cooling amount as described above, the cooling amount in the width direction of the gas jet nozzles 4a, 4b is determined by inputting the outlet plate temperature profile, and the valve
40, and controls the widthwise cooling amount of the nozzles 4a, 4b so that the outlet plate temperature profile becomes constant (of course, as a result of the gas jet cooling by these nozzles 4a, 4b, the plate temperature of the strip X is The total cooling amount is also adjusted so that the target outlet plate temperature will be).

As described above, in the structure of this embodiment, the bridle rolls 3a and 3b apply a predetermined tension to the strip X to suppress the amount of floating of the strip edge portion in contact with the large diameter cooling roll 1. By doing so, the fluttering of the strip X is reduced, and the scratches due to the contact between the gas jet nozzles 4a and 4b and the strip X are also eliminated, so that the distance between the nozzles 4a and 4b and the strip X can be shortened. Therefore, the edge portion can be cooled efficiently. As the spray gas, H ₂ 40
A gas with a high heat transfer coefficient of ˜90% and N _{2 of} 10 to 60% is used.

The gas jet nozzles 4a and 4b are plate thermometers.
Since the high temperature portion centered on the edge of the strip X measured in 5 is actively cooled, uniform cooling can be expected.

Further, in this embodiment, since the strip X is uniformly cooled at a predetermined temperature by one cooling roll having a large diameter, the high temperature edge portion on the outlet side of the cooling roll 1 extends to the central portion of the strip width. Since it can be suppressed, the gas jet nozzle 4a,
The cooling load of 4b can be reduced.

FIG. 2 shows the widthwise plate temperature profile obtained by carrying out this embodiment, and FIG. 3 shows the results of the aging index test in the strip X widthwise direction. As shown in these figures, the widthwise plate temperature profile on the outlet side of the roll cooling device was uniform, and the shape collapse did not occur. Further, since it is possible to prevent the portion of the edge portion having a poor aging index from reaching the central portion of the plate width, it is possible to manufacture a product having a more uniform material.

[0020]

According to the structure of the strip cooling device of the present invention as described above, it is possible to prevent the uneven cooling in the width direction generated in the cooling roll group from being suppressed to a minimum and to reduce the cooling load of the gas jet nozzle. In addition to being able to reduce the equipment cost and operating cost, a uniform material can be obtained in the width direction, and also in the operating side, the strip shape does not collapse at the exit of the cooling roll group, and stable production is performed. Will be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a roll cooling device configuration to which the configuration of the present invention is applied.

FIG. 2 is a graph showing a temperature distribution of a strip edge portion obtained by the configuration of this embodiment.

FIG. 3 is a graph showing the aging index distribution of the strip edge portion obtained in the configuration of this embodiment.

FIG. 4 is a perspective view showing a strip deformation model at the time of winding a roll.

FIG. 5 is an explanatory diagram of a floating portion that occurs at a strip edge portion when winding a roll.

FIG. 6 is a graph showing the relationship between the amount of lift and the tension that occurs at the strip edge portion when wound around a roll.

FIG. 7 is a graph showing the relationship between the amount of lift and the curvature of the strip that occur at the strip edge when the roll is wound.

FIG. 8 is a graph showing a temperature distribution at a strip edge portion obtained by the conventional configuration.

FIG. 9 is a graph showing the aging index distribution of the strip edge portion obtained by the conventional configuration.

FIG. 10 is a graph showing a temperature drop amount and a temperature distribution of a strip edge portion obtained when cooled by a conventional configuration.

FIG. 11 is an explanatory diagram showing a conventional roll cooling configuration.

[Explanation of symbols]

 1 Cooling roll 2a, 2b Movable deflector roll 3a, 3b Bridle roll 4a, 4b Gas jet nozzle 5 Plate thermometer 6 Control computing device X strip

Claims (1)

[Claims] 1. At least one of the one or more cooling rolls has a large diameter, and the large diameter cooling roll is moved around the roll so as to contact the roll with the strip. In addition to having two or more movable deflector rolls with adjustable corners, bridle rolls are arranged on the inlet side and outlet side of the cooling roll, and the cooling amount in the strip width direction can be adjusted between the cooling roll outlet side and outlet side bridle roll. Gas jet nozzle is installed, and a plate thermometer capable of measuring the temperature profile in the strip width direction is installed on the exit side bridle roll side, and the cooling amount in the strip width direction of the gas jet nozzle is adjusted based on the measured value. A strip cooling device for continuous annealing, comprising a control arithmetic device.