JPH0527691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a gas jet cooling zone installed in a continuous annealing furnace.

[Conventional technology]

In a continuous annealing furnace, cooling gas is ejected onto the strip surface from the nozzle of a gas ejection header that extends in the width direction of the strip and is provided in multiple stages in the strip running direction. Gas jet cooling methods are often used.

[Problem that the invention seeks to solve]

However, when the strip is cooled by such a method, the edge portions of the strip are likely to be cooled, so that the temperature distribution in the width direction of the strip becomes a mountain-shaped distribution where the edge portions are lowered. Also, depending on the shape of the header and the direction of gas supply, the plate temperature distribution is not symmetrical, and the high temperature portion is biased toward one side.

When such a temperature distribution occurs, the shape of the strip becomes asymmetrical, causing a meandering problem in the roll cooling zone, overaging treatment zone, etc. installed after the gas jet cooling zone.

In order to adjust the left-right balance, a configuration in which the header is divided into a plurality of parts has been proposed. However, in a header with a small number of divisions, the difference in air volume at the partition positions of the division parts becomes large, making it difficult to smoothly balance the plate temperature distribution. In order to smoothly adjust the plate temperature, it is necessary to divide the plate into many parts, but in this case the ductwork becomes complicated.

In addition, as one of the other means of adjusting the cooling distribution in the strip width direction, "Steel Manufacturing Research No. 304 (1981)"
On page 89 of , the configuration of a cooling tube for adjusting cooling distribution is disclosed. These cooling tubes are arranged in parallel in the running direction of the strip, symmetrically with respect to the center of the strip width, in a C shape and an inverted C shape, and the cooling amount distribution can be adjusted by changing the amount of air flowing into each tube individually. It is something to do.

However, in such a tube shape, all of the cooling gas flow paths are installed parallel to the strip, and the cooling gas flows from both sides of the strip in the width direction of the strip.
Or, since a plurality of tubes are interposed in a complicated manner in the width direction, such as inverted Cs arranged in a layered manner (Baumkuchen shape), there is a problem in terms of controllability of cooling distribution.

Furthermore, as one of other configurations for adjusting cooling distribution, a method has been proposed in which a plurality of width direction nozzles are arranged to perform cooling. One of these nozzles has a concave shape with a symmetrical air volume in the width direction, and the other nozzle has a convex shape with a symmetrical air volume in the width direction.
Variable cooling is possible by adjusting the overall air volume to each nozzle.

However, with this type of left-right symmetrical system, it may be possible to make the left and right sides the same at one optimal point in the nozzle design, but by changing the cooling amount in the width direction, it is not possible to stabilize the temperature or consciously adjust the temperature. It cannot be applied when making adjustments outside the optimal design point, and it is impossible to make the left and right sides the same when making adjustments outside of the optimal design point, and the maintenance, maintenance, etc. of equipment are extremely sophisticated, which is also impractical from this point of view.

The present invention has been devised in view of the above-mentioned current situation, and has a device configuration that improves the gas jet header that constitutes the gas cooling device of the gas jet cooling zone and can control the temperature distribution in the width direction of the strip after cooling is completed. The objective is to improve the stability of the strip in the roll cooling zone and overaging treatment zone provided after the gas jet cooling zone.

[Means for solving problems]

Therefore, the present invention divides each gas jet header, which is provided in a plurality of stages in the strip running direction, constituting the gas cooling device of the gas jet cooling zone, into two in the strip width direction, and changes the dividing position for each stage. A right gas supply device that supplies gas to all the headers on the right side of these dividing positions and a left gas supply device that supplies gas to all the headers on the left side are provided, and a strip width direction is provided on the outlet side of the cooling device. A temperature measuring device for measuring plate temperature is provided, and an arithmetic control device is provided for controlling the gas supply amount of each of the gas supply devices based on the plate temperature distribution in the strip width direction measured by the temperature measuring device. This is a basic feature.

Furthermore, in order to improve the configuration of the gas jet cooling zone for the continuous annealing furnace to a configuration capable of controlling the plate temperature profile, a second invention consisting of the following configuration was also simultaneously invented.

That is, the second invention divides each gas jetting header, which is provided in a plurality of stages in the strip running direction, constituting the gas cooling device of the gas jet cooling zone into two in the strip width direction, and changes the dividing position for each stage. A right side gas supply device that supplies gas to all the headers on the right side of these division positions and a left side gas supply device that supplies gas to all the headers on the left side are provided, and furthermore, a Previous and/
Or, later, a center cooling nozzle that cools the center portion in the width direction of the strip is arranged, and a center gas supply device is installed to supply gas to the nozzle.
A temperature measuring device for measuring the temperature of the strip in the width direction of the strip is installed on the outlet side of these gas cooling devices, and the gas supply of the three gas supply devices is controlled based on the temperature distribution of the strip in the width direction of the strip measured by the temperature measuring device. The basic feature is that an arithmetic control device is provided to control each amount.

[Effect]

In the first invention, even if the right side gas supply device (or left side gas supply device) supplies gas only to all headers on the right side (or left side) of the dividing position, the air volume pattern that collides with the strip will be on the right side (or left side). )
A smooth pattern that gradually decreases toward the left (or right) is obtained, and the plate temperature distribution can also be smoothly adjusted. Therefore, if the plate temperature in the width direction of the strip at the outlet side of the cooling device is measured with a temperature measuring device, and the gas supply amount of the right and left gas supply devices is controlled by the arithmetic and control unit based on the plate temperature distribution, the plate temperature distribution can be determined. This means that the balance can be adjusted.
In order to achieve such a smooth air flow pattern, the number of headers divided into two parts must be increased, and the header division positions (in terms of number) must be balanced on the left and right sides of the strip center. The clearer it is, the better.

Furthermore, in the second invention, in addition to adjusting the balance of the plate temperature distribution with the above-described configuration, it is possible to further cool the center portion in the width direction of the strip by the center cooling nozzle and the center gas supply device.
It is possible to control the plate temperature profile by making the center part colder than the strip edge part.

〔Example〕

Examples of the present invention will be described below.

1 and 2a and 2b show one embodiment of the present invention, FIG. 1 is an explanatory diagram showing the overall equipment configuration of the gas jet cooling zone in a continuous annealing furnace, and FIG. A front view showing an example of the arrangement of gas jetting headers that constitute the gas cooling device in the cooling zone;
FIG. 5B is a graph showing the gas air volume pattern caused by the header.

The gas jet cooling zone of the present invention includes #1 to #15 double-sided gas jet headers 2 that constitute a gas cooling device.
a, 2b, right and left gas supply devices 3, 4 that supply gas to these headers 2a, 2b, and a temperature measuring device 5 provided on the outlet side of the gas cooling device.
and an arithmetic control device 6 that controls the gas supply amount of both gas supply devices 3 and 4, respectively. In the figure, numeral 1 indicates a strip running inside the continuous annealing furnace.

The double-sided gas ejection headers 2a and 2b are provided in 15 stages (#1 to #15) on both sides of the strip 1 along the running direction of the strip 1.
Each header is divided into two in the width direction of the strip 1, and the positions of these divisions are changed for each header 2a, 2b, so that they are arranged in a staggered manner around the center of the strip 1. To explain the division position in detail, each header 2a, 2b has a total length of 1200 mm when the left and right sides are combined.
However, as shown in Figure 2a, the #1 header is divided at the strip center position, and the left and right lengths are 600 mm each. Also, the #2 header is divided at a position 150mm to the right of the center, and the #3 header is divided at a position 150mm to the left of the center.
Headers #4 and #5 are also divided at similar positions. Furthermore, #6 to #11 headers are divided at a position of 225 mm to the right or left side of the center position, and #12
The 15# to 15# headers are divided at positions of 300 mm to the right or left of the center position.

The gas supply devices 3 and 4 are composed of a blower 30 serving as a cooling gas supply source, and a right control valve CV ₁ and a left control valve CV ₂ provided in respective flow paths that are divided into two at the tip thereof. However, in the right side gas supply device 3, the flow path from the right side control valve CV ₁ is further connected to all the headers 2a, 2b on the right side of each division position of the gas jetting headers 2a, 2b, and these headers are connected to each other. Cooling gas can be supplied to 2a and 2b. Also, left side gas supply device 4
The flow path beyond the left control valve CV ₂ is connected to all the headers 2a, 2b on the left side of each division position, and supplies cooling gas to these headers 2a, 2b. In the figure, reference numeral 40 denotes a regulating valve that opens and closes all gas supplies from the blower 30 and adjusts the supply amount.

The temperature measuring device 5 is a profile thermometer that measures the plate temperature in the width direction of the strip 1 on the exit side of the cooling device, and in the present invention, based on the plate temperature profile measured here, feedback is performed to perform the calculation described below. Each gas jetting header 2 is controlled by the control device 6.
The amount of cooling gas supplied to a and 2b will be determined. Further, although a profile thermometer is used in this embodiment, a plurality of plate thermometers may be arranged in the width direction of the strip 1, or a scan type thermometer may be used.

Further, the arithmetic and control device 6 inputs the temperature profile of the strip 1 in the width direction measured by the temperature measuring device 5, and controls the gas supply amount of the right side gas supply device 3 and the left side gas supply device 4, respectively, based on this. This is used to adjust the plate temperature balance. That is, when the plate temperature profile is not smoothed and balanced, the total amount of gas blown to the left and right sides of all the headers 2a and 2b required to smooth the profile is calculated, and both gas supply devices Determine the appropriate value for each gas supply amount in steps 3 and 4. Based on this, the arithmetic and control device 6 adjusts the opening degree of each of the control valves CV ₁ and CV ₂ .

Next, in order to understand how dividing the gas ejection headers 2a and 2b as described above affects the balance adjustment of the plate temperature distribution in the width direction of the strip 1, 2
The basic air flow pattern according to the method b will be explained, and then the method of cooling the strip 1 using the gas jet cooling zone of this embodiment will be explained.

Among the gas ejection headers 2a and 2b having the above configuration,
All headers 2a and 2b on the right side of each division position
When cooling gas is flowed from the right side gas supply device 3 only to the right side, an air flow pattern as shown in FIG. 2b is obtained. Therefore, by flowing the cooling gas from both the gas supply devices 3 and 4 to all the left and right headers 2a and 2b, a smooth air flow pattern can be obtained.

In this embodiment, when the strip temperature distribution in the width direction of the strip 1 on the outlet side of the cooling device measured by the temperature measuring device 5 shows a profile as shown in FIG. 3, the strip temperature at the center of the strip 1 is set as _T3 . , if the plate temperatures at each point equally spaced on both sides in the width direction are T ₁ , T ₂ , T ₄ , and T ₅ , the outputs of the temperature measuring device 5 are T 1 to T ₅ .
For T ₅ , θ ₁ = 1/3 (T ₁ + T ₂ + T ₃ ) θ ₂ = 1/3 (T ₃ + T ₄ + T ₅ ) are determined by the arithmetic and control unit 6, and further |θ ₁ −θ ₂ |< The arithmetic and control device 6 adjusts the opening degrees of the right-hand control valve CV ₁ and the left-hand control valve CV ₂ so that ε, thereby adjusting the balance between the left and right plate temperatures.

That is, in the case of |θ ₁ −θ ₂ |ε If θ ₁ <θ ₂ , the opening degree of the right control valve CV ₁ is increased and the opening degree of the left control valve CV ₂ is decreased.
If θ ₁ > θ ₂ , the adjustment is made in the opposite manner.

Note that ε is a threshold value set in advance by the operator, and is set to about 5° C., for example.

FIG. 4 is an explanatory diagram showing the configuration of an apparatus according to an embodiment of the second invention, which has almost the same configuration as the embodiment described above, except that in the gas jet cooling zone, a Double-sided center cooling nozzles 7a and 7b of Δ1 to Δ3 and these nozzles 7
A center gas supply device 8 is newly installed to supply cooling gas to the a and 7b, and furthermore, the arithmetic and control unit 6 separately controls the gas supply amount of the center gas supply device 8 in addition to the right and left gas supply devices 3 and 4. If necessary, it is possible to obtain a temperature profile that lowers the plate temperature at the strip 1 center.

The double-sided center cooling nozzles 7a and 7b are provided on both sides of the strip 1 to cool the center of the strip 1, but in this embodiment, three nozzles on each side (Δ1 to Δ3) with different nozzle widths are provided. ) center cooling nozzles 7a and 7b are provided in three stages each in the running direction of the strip 1, so that the strip temperature profile can be controlled in accordance with the width of the strip 1 to be threaded.

Further, the center gas supply device 8 has the strip 1
A blower 80 that serves as a cooling gas source when performing center cooling, and three center control valves CV ₃ , CV ₄ , CV ₅ provided in each of the three flow paths separated from the blower 80.
Further, the flow path beyond these control valves is divided into two, and Δ1 center cooling nozzles 7a, 7b, Δ2 center cooling nozzles 7a, 7b, and Δ3 center cooling nozzles 7a, 7 are provided on both sides of the strip 1.
These nozzles 7a,
7b can be supplied with cooling gas.

Further, when the arithmetic and control device 6 controls the gas supply amount of the center gas supply device 8, the three center control valves CV ₃ , CV ₄ , CV ₅ are adjusted according to the strip width of the strip 1 and the desired strip temperature profile. Adjust the opening.

Next, the method of cooling the strip 1 using the gas jet cooling zone of this embodiment will be explained.

First, in this embodiment, as in the embodiment of the first invention, the opening degrees of the right and left control valves CV ₁ and CV ₂ are adjusted to adjust the balance between the left and right plate temperatures.

Furthermore, the arithmetic and control unit 6 calculates θ ₃ = 1/2 (T ₁ + T ₅ ) θ ₄ = 1/3 (T ₂ + T ₃ + T ₄ ) Δθ = θ ₃ - θ ₄ , so that δ ₁ <Δθδ ₂ . By adjusting the opening degrees of the three center control valves CV ₃ , CV ₄ and CV ₅ using the arithmetic and control unit 6, a plate temperature profile as shown in FIG. 5 can be obtained.

Note that δ ₁ and δ ₂ are threshold values set in advance by the operator; for example, δ ₁ is approximately 5°C, and δ ₂ is 15°C.
Set it to about.

[Effects of the Invention] As detailed above, according to the gas jet cooling zone of the present invention, the air volume distribution of the cooling gas blown in the width direction of the strip can be smoothly changed, so that the balance adjustment of the plate temperature profile can be easily adjusted. It has the excellent effect of being able to perform the process smoothly, and as a result, the strip threading stability is ensured in each continuous annealing furnace installed after the main gas jet cooling zone, thereby promoting operational stability. I can do it.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the overall device configuration of the gas jet cooling zone according to the embodiment of the first invention, and FIG.
1 is a front view showing an example of the arrangement of gas jet headers constituting the gas cooling device of the gas jet cooling zone, and FIG.
3 is a graph showing the gas flow pattern by these headers, FIG. 3 is a graph showing the temperature distribution in the width direction of the strip plate measured by a temperature measuring device, and FIG. 4 is a graph showing the gas jet cooling according to the embodiment of the second invention. FIG. 5 is an explanatory view showing the overall device configuration of the strip, and FIG. 5 is a graph showing the temperature distribution in the width direction of the strip plate measured by the temperature measuring device in this embodiment. In the figure, 1 is a strip, 2a and 2b are gas ejection headers, 3 is a right gas supply device, 4 is a left gas supply device, 5 is a temperature measurement device, 6 is an arithmetic and control device,
7a and 7b are center cooling nozzles, and 8 is a center gas supply device.

Claims (1)

[Scope of Claims] 1. Each gas jetting header provided in multiple stages in the strip running direction constituting the gas cooling device of the gas jet cooling zone in a continuous annealing furnace is divided into two in the strip width direction, and each division position is A right side gas supply device that supplies gas to all the headers on the right side of these division positions and a left side gas supply device that supplies gas to all the headers on the left side of the dividing position, which are changed for each stage, are provided, and the cooling device A temperature measuring device for measuring strip temperature in the strip width direction is provided on the outlet side, and calculation control controls the gas supply amount of each of the gas supply devices based on the strip width direction plate temperature distribution measured by the temperature measuring device. A gas jet cooling zone for a continuous annealing furnace characterized by being equipped with a device. 2. Each gas jetting header, which is provided in multiple stages in the strip running direction and which constitutes the gas cooling device of the gas jet cooling zone in a continuous annealing furnace, is divided into two in the strip width direction, and the position of each division is changed for each stage, A right side gas supply device that supplies gas to all the headers on the right side of these division positions and a left side gas supply device that supplies gas to all the headers on the left side are provided. /Or later, a center cooling nozzle that cools the center part in the width direction of the strip is installed, and a center gas supply device is installed to supply gas to the nozzle, and the plate temperature in the width direction of the strip is adjusted on the outlet side of these gas cooling devices. It is characterized by being provided with a temperature measuring device for measuring the temperature, and an arithmetic control device for controlling the gas supply amount of each of the three gas supply devices based on the strip widthwise plate temperature distribution measured by the temperature measuring device. Gas jet cooling zone for continuous annealing furnace. 3. The gas jet cooling zone for a continuous annealing furnace according to claim 2, wherein a plurality of center cooling nozzles with different nozzle widths are provided in the strip running direction in the gas jet cooling zone for a continuous annealing furnace.