JPH05228525A - Width-direction temperature control method and apparatus for hot-rolled steel strip - Google Patents

Abstract

(57) [Summary] [Purpose] In hot run cooling, the temperature nonuniformity in the strip width direction, which has conventionally occurred, is eliminated and the temperature distribution in the width direction is made uniform. In a method of hot-run cooling a hot-rolled strip 2, width-direction temperature detectors 4 and 5 provided on an exit side of a finish rolling mill 1 and an inlet side of a winding machine 3 of a hot-rolling line are used to detect the width direction. The temperature distribution is continuously measured, and apart from the hot run spray header 8 group, a plurality of side spray nozzles 12 that can freely control the spray angle and the sprayed water amount are arranged facing each other on both sides of the strip 2 width direction. A side spray nozzle 12 for injecting cooling water to a position in the width direction of the maximum temperature together with the amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero based on the measurement result of the temperature distribution in the direction.
The injection angle of the side spray nozzle 12 and the injection amount of water are controlled based on the calculation result. [Effect] The temperature distribution in the strip width direction during hot run cooling can be made uniform, and non-uniformity in quality due to the temperature difference between both edge portions and the central portion can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strip width direction temperature control method and apparatus on a hot run table for cooling hot rolled hot steel strip (hereinafter referred to as strip).

[0002]

2. Description of the Related Art The rolling temperature in hot rolling is an important factor that determines the material properties, of which the finish rolling mill outlet temperature and winding temperature greatly affect the crystal grain structure,
Sufficient control is required to determine YP and E1. Hot run cooling is usually performed at a finish rolling temperature of 87.
By cooling from around 0 ° C. to a coiling temperature of around 550 ° C., the strip running at high speed must be cooled in a limited space and time, and the cooling end temperature must be controlled within a strict range. In addition, there are restrictions on the cooling system and the installation position of the cooling equipment. Generally, the upper cooling is a lamina system and the lower cooling is a spray system.

The cooling by the lamina method breaks the vapor film with a large kinetic energy of a rod-shaped water flow or water droplets, and water and the strip surface are in good contact with each other to obtain a high heat transfer coefficient. In order to control the winding temperature of the strip running at high speed, it is important to shorten the time of water injection and water cutoff. For this reason, on / off valves having a good response such as a piston valve, a three-way valve, and a butterfly valve are used. The cooling by the lamina method is such that the nozzle header is arranged above the strip passing on the hot run table at a right angle to the traveling direction of the strip, and one end of the inverted U-shaped tube is communicated with the nozzle header, and
A large number of lamina flow nozzles for jetting cooling water downward from the other end of the character tube are installed in the width direction of the strip, and cooling water is jetted from the lamina flow nozzles to cool the strip. However, in the above cooling method, the strip width direction both edge portions have a larger contact area with the cooling water and the heat radiation area than the center portion, so that both width direction edge portions are more easily cooled than the center portion. For this reason, even if the water amount distribution in the strip width direction is uniform, the temperature at both edges of the strip is lower than the temperature at the center, and the mechanical properties in the width direction are also different between the edges and the center. There is a problem that they are different.

As a conventional method for equalizing the temperature distribution in the strip width direction in hot run cooling, as shown in FIGS. 6 and 7, a lamina flow nozzle 22 is arranged above the strip 21 in the width direction so as to face the strip 21. While installing the lamina flow nozzle 22 and the strip 2
1, a water receiving plate 23 for changing the direction of the cooling water from the lamina flow nozzle 22 to adjust the water injection width to the strip 21.
Is provided so as to be movable in the width direction of the strip 21, and a gutter 24 for draining the cooling water received by the water receiving plate 23 is provided in the vicinity of the water receiving plate 23 (Japanese Patent Laid-Open No. 59-197313). A number of rows of slit laminar nozzles are arranged almost at right angles to the sheet passing direction of the strip, and the cooling water is discharged across these strip laminar nozzles diagonally to the sheet passing direction and across the entire width of the strip. A method (Japanese Patent Laid-Open No. 1-100224) has been proposed in which a nozzle is disposed and a discharge flow layer having a different flow direction with respect to the strip width direction is formed in the vicinity immediately below the auxiliary nozzle.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The device disclosed in Japanese Patent No. 7313 not only requires a great amount of cost and time for maintenance for maintaining the gutter so that it can always be operated normally, but also has a defective shape when the shape of the strip is disturbed by cooling. There is a drawback that cooling water accumulates in a portion and is supercooled. In addition, Japanese Patent Laid-Open No. 1-
The method disclosed in Japanese Unexamined Patent Publication No. 100224 can eliminate the occurrence of the interference zone of the water stream on the strip which causes the reduction of the cooling ability of the water film collision surface in the plate width direction, and can prevent the reduction of the cooling ability of the central portion in the width direction. However, it does not prevent the temperature drop at both edges.

An object of the present invention is to provide a width direction temperature control method and apparatus in hot run cooling which can eliminate the temperature nonuniformity in the strip width direction which has been conventionally generated in hot run cooling and which is excellent in maintainability. ..

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies to achieve the above object. As a result, while continuously measuring the temperature distribution in the strip width direction on the finishing rolling mill outlet side and the winder inlet side of the hot rolling line, it is opposed between the hot run spray header groups and on both sides in the strip width direction. By arranging multiple side spray nozzles that can freely control the spray angle and spray water amount, obtain the amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero based on the temperature distribution measurement results in the strip width direction. At the same time, the injection angle of the side spray nozzle for injecting the cooling water at the maximum temperature width direction position is obtained, and the temperature difference between the maximum temperature and the minimum temperature is made zero at the maximum temperature width direction position through the cooling control unit. It was concluded that the temperature in the strip width direction can be made uniform by injecting the cooling water necessary for the above, and the present invention was reached.

That is, the present invention relates to a method of hot-run cooling a hot-rolled high-temperature steel strip in which the temperature distribution in the strip width direction is continuously made on the finish rolling mill outlet side and the winder inlet side of the hot rolling line. Based on the temperature distribution measurement results in the strip width direction, multiple side spray nozzles that can freely control the injection angle and the amount of water sprayed are arranged between the hot run spray header groups and facing each other in the strip width direction. Along with the amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero, the spray angle of the side spray nozzle for spraying the cooling water to the position of the maximum temperature in the width direction is calculated, and the spray based on the calculation result is calculated. The jet angle of the nozzle and the amount of jet water are controlled.

Further, in an apparatus for hot-run cooling a hot-rolled high-temperature steel strip, the temperature distribution in the strip width direction provided on the exit side of the finish rolling mill and the entrance side of the winding machine of the hot rolling line is continuously measured. Width direction temperature detector, a plurality of hot run spray header groups facing each other across the strip width direction, side spray nozzles that can freely control the injection angle and the amount of water injected, and the temperature distribution of the width direction temperature detector The amount of cooling water required to make the temperature difference between the highest temperature and the lowest temperature zero based on the measurement result, and the injection angle of the side spray nozzle for injecting the cooling water to the widthwise position of the highest temperature are calculated, and the calculation is performed. The temperature control device in the width direction includes a cooling control device that controls the injection angle of the side spray nozzle and the amount of water injection based on the results.

[0010]

According to the present invention, the amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero based on the measurement result of the temperature distribution in the width direction of the strip, and the cooling water is jetted to the position of the maximum temperature in the width direction. The spray angle of the side spray nozzle is calculated, and the spray angle of the side spray nozzle and the sprayed water amount are controlled based on the calculation result. It is locally cooled by the spray nozzle. As a result, the temperature distribution in the strip width direction is made uniform, and the mechanical properties of the strip are also made uniform at both edge portions and the central portion.

[0011]

【Example】

Embodiment 1 Hereinafter, details of the present invention will be described with reference to FIGS. 1 to 3 showing an embodiment. FIG. 1 is a control system diagram showing an embodiment of the present invention, FIG. 2 is a control explanatory view of a side spray nozzle when there is a high temperature portion in the center in the strip width direction, and FIG. 3 is a high temperature portion in the left direction in the strip width direction. It is a control explanatory view of the side spray nozzle in the case. In FIG. 1, 1 is a finish rolling mill of a hot rolling line, 2 is a hot rolled strip, 3 is a winder, and strip 2 rolled by the finish rolling mill 1 is wound by a winder 3. In the meantime, it is cooled to the winding temperature in the hot run table. 4 is a width direction temperature detector provided above the exit of the finish rolling mill 1, and 5 is a winder 3.
Is a width-direction temperature detector provided above the entrance of the. 6 is a thermometer provided above the exit of the finish rolling mill 1, and 7 is a thermometer provided above the entrance side of the winder 3. 8 is a hot run spray header, each hot run spray header 8 has a reverse U
The letter-shaped lamina spray nozzle 9 is connected. Although not shown, a header group having spray type nozzles for cooling the lower surface is disposed below the strip 2. 10 is each hot run spray header 8
The ON / OFF valve 11 is a cooling control device, which is based on the surface temperature of the strip 2 input every time each temperature measurement sampling point in the longitudinal direction of the strip 2 passes directly under the thermometer 6 at the exit of the finishing rolling mill 1. When the sampling point reaches just below the thermometer 7 at the inlet of the winder 3, the number of hot run spray header 8 groups used is calculated so that the ON / OFF valve 10 can be cooled to a predetermined winding temperature. It is configured to control ON / OFF of each ON / OFF valve 10 of the group.

Further, based on the temperature distribution in the width direction of the strip 2 input every time each temperature measurement sampling point in the length direction of the strip 2 passes immediately below the width direction temperature detector 4 at the exit of the finishing rolling mill 1. , The side spray nozzles 12 are calculated from the maximum temperature position while calculating the water injection amount of the side spray nozzles 12 group from the temperature difference between the maximum temperature and the minimum temperature.
The injection angle of the group is calculated, the injection water amount of the flow rate adjusting valve 13 is controlled based on the calculation result, the injection angle of the angle setting device 14 group is controlled, and the sampling point is the width of the inlet of the winder 3. The temperature distribution in the width direction of the strip 2 becomes a predetermined temperature distribution when it reaches the position just below the direction temperature detector 5.

With the above construction, in hot run cooling, the cooling control device 11 is input each time each temperature measurement sampling point in the longitudinal direction of the strip 2 passes immediately below the thermometer 6 at the exit of the finishing rolling mill 1. Based on the surface temperature of the strip 2, the number of hot run spray header 8 groups used is adjusted so that the sampling point reaches a position just below the thermometer 7 at the inlet of the winder 3 so that the hot run spray header 8 is cooled to a predetermined winding temperature. Calculates each ON / OFF of each group of 10 ON / OFF valves
The ON / OFF of the OFF valve 10 is controlled. Further, the cooling control device 11 inputs the temperature distribution in the width direction of the strip 2 each time each temperature measurement sampling point in the length direction of the strip 2 passes just below the width direction temperature detector 4 at the exit of the finishing rolling mill 1. Based on, calculate the water injection amount of the side spray nozzle 12 group required to make the temperature difference between the maximum temperature and the minimum temperature zero, and calculate the injection angle of the side spray nozzle 12 group based on the maximum temperature position, Based on the calculation result, the injection water amount of the flow rate adjusting valve 13 is controlled, and the injection angle of the angle setting device 14 group is controlled. For example, when the maximum temperature in the width direction is in the center, as shown in FIG.
The spray angles θ ₁ and θ _{2 of the} left side spray nozzle 12a and the right side spray nozzle 12b are the same (θ ₁ = θ ₂ ).
Is set to. Further, when the maximum temperature in the width direction deviates from the center to the left edge side, as shown in FIG. 3, the injection angle θ ₁ of the right side spray nozzle 12b is more than the injection angle θ ₂ of the left side spray nozzle 12a. Large angle (θ ₁
<Θ ₂ ) is set.

Control based on the temperature measurement result of the width direction temperature detector 4 on the exit side of the finish rolling mill 1 (feedforward control)
Is carried out over the entire length with respect to the longitudinal sampling points of the strip 2. In the cooling control device 11, the width direction temperature detector 5 in which the tip of the strip 2 is the inlet of the winder 3 is used.
Based on the temperature distribution in the width direction that is input immediately below, the jet water amount and jet angle of the side spray nozzles 12 group are calculated in the same manner as above, and the jet water amount and jet angle of the side spray nozzles 12 group are corrected. To do. Therefore, since the temperature distribution in the width direction of the strip 2 is controlled by calculating and controlling the water injection amount and the water injection angle of the side spray nozzles 12 group based on the temperature measurement result in the width direction, the temperature distribution is made uniform between both edge portions and the central portion. The temperature difference is eliminated.

Example 2 In the hot run cooling apparatus, the plate thickness of 3. was used for each of the case of the method of the present invention using the width direction temperature control apparatus of Example 1 and the case of the conventional method in which the width direction temperature control was not performed.
Hot-run cooling of a strip having a width of 0 mm and a plate width of 1200 mm was performed. Then, the temperature distribution in the strip width direction at the inlet of the winder was measured. The result is shown in FIG. Further, a test piece was cut out from the obtained hot rolled steel strip, and the tensile strength in the strip width direction was measured. The result is shown in FIG.

As shown in FIGS. 4 and 5, in the case of the method of the present invention in which the temperature control in the strip width direction is performed, the temperature difference between the maximum temperature and the minimum temperature in the strip width direction and the strip width direction are compared with the conventional method. The tensile strength of is reduced to about 1/4, and the temperature distribution and the tensile strength are made uniform.

[0017]

As described above, according to the present invention,
The temperature distribution in the strip width direction during hot run cooling can be made uniform, and unevenness in quality due to the temperature difference between both edge portions and the central portion can be prevented. In addition, since it does not require a complicated structure unlike the gutter method disclosed in Japanese Patent Laid-Open No. 59-197313, it is not only excellent in maintainability, but also unnecessary cooling water is not discarded. Further, since the time from the closing to the stop of the cooling water dropping is short, the supercooling of the strip can be prevented.

[Brief description of drawings]

FIG. 1 is a control system diagram showing an example of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of control of a side spray nozzle when there is a high temperature portion in the center of the strip width direction.

FIG. 3 is a control explanatory diagram of a side spray nozzle when there is a high temperature portion in the left direction of the strip width direction.

FIG. 4 is a graph showing a temperature pattern in a strip width direction in Example 2.

FIG. 5 is a graph showing a tensile strength pattern in the strip width direction in Example 2.

FIG. 6 is a front view of a hot run cooling device disclosed in JP-A-59-197313.

FIG. 7 is a schematic side view of FIG.

[Explanation of symbols]

 1 Finishing Rolling Machine 2, 21 Strip 3 Winding Machine 4, 5 Width Direction Temperature Detector 6, 7 Thermometer 8 Hot Run Spray Header 9, 22 Lamina Flow Nozzle 10 ON / OFF Valve 11 Cooling Control Device 12 Side Spray Nozzle 13 Flow Rate Adjusting valve 14 Angle setting device 23 Water receiving plate 24 Retracting gutter

Claims (2)

[Claims] 1. A method for hot-run cooling a hot-rolled high-temperature steel strip, wherein the temperature distribution in the width-direction of the high-temperature steel strip is continuously measured on the exit side and finisher side of the hot rolling line. However, multiple side spray nozzles that can freely control the injection angle and the amount of water injected are arranged between the hot run spray header groups and on both sides of the high temperature steel strip width direction. Based on the above, together with the amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero, the injection angle of the side spray nozzle for injecting the cooling water to the widthwise position of the maximum temperature is calculated, and the calculation result is A method for controlling a widthwise temperature of a hot-rolled steel strip, characterized by controlling an injection angle of a side spray nozzle and an amount of injected water based on the above. 2. A device for hot-run cooling a hot-rolled high-temperature steel strip, wherein the temperature distribution in the width-direction of the high-temperature steel strip provided on the exit side of the finish rolling mill and the inlet side of the winder of the hot rolling line is continuous. The width direction temperature sensor, the hot run sprayer header group, and the side spray nozzles that can freely control the injection angle and the amount of water that are arranged facing each other on both sides of the high temperature steel strip width direction, and the width direction The amount of cooling water required to make the temperature difference between the maximum temperature and the minimum temperature zero based on the temperature distribution measurement result of the temperature detector, and the spray angle of the side spray nozzle for spraying the cooling water in the widthwise position of the maximum temperature. And a width direction temperature control device for the hot-rolled steel strip, which comprises a cooling control device for controlling the injection angle of the side spray nozzle and the water injection amount based on the calculation result.