JP2010131644A - Method of controlling supply of cooling water in water-cooling apparatus of bar and shape rolling equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling the supply of cooling water in the water-cooling apparatus of bar and shape rolling equipment, by which it is possible to make the flow rate of cooling water supplied to the body of the water-cooling apparatus attain to the set value of flow rate quickly. <P>SOLUTION: The water-cooling apparatus of the bar and shape rolling equipment includes: the body 10 of the water cooling apparatus; a cooling water supplying line 20 which has a flow meter 21, a flow rate regulating valve 22 and a three-way valve 23 and connects with the supply source of the cooling water; and a bypass line 30 which is branched from the three-way valve 23. In the water-cooling apparatus, whenever rolled stocks are guided on, the bypass line 30 is switched to the cooling water supplying line 20 by the three-way valve 23 and, when starting the opening degree regulation of the flaw rate regulating valve 22, the command value of the opening degree which is obtained in the water cooling of the rolled stock at the last rolling is given to the flow rate regulating valve 22 as the command value of the opening degree. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling water supply control method in a water cooling device of a steel strip rolling facility.

  In a strip rolling facility that manufactures steel bars and steel wires by hot rolling, a water cooling device may be installed online to control the temperature of the rolled material. For example, when performing controlled rolling at a lower rolling temperature, particularly a finishing temperature for composition control, a water cooling device (intermediate water cooling device) having a large cooling capacity is installed between the intermediate rolling mill row and the finishing rolling mill row. .

  FIG. 1 is a diagram schematically showing a configuration of a water cooling device installed between an intermediate rolling mill row and a finishing rolling mill row in a strip rolling mill.

  As shown in FIG. 1, the water-cooling device includes a water-cooling device body (immersion-type water-cooling device) 10 installed between the intermediate rolling mill row 60 and the finishing rolling mill row 70, and a flow meter 21 in order from the upstream side. A cooling water supply line 20 that has a flow rate adjusting valve 22 and a three-way valve 23 and connects a cooling water supply source (not shown) and the water cooling device main body 10, and branches from the three-way valve 23, and the water cooling device main body 10 And a bypass line 30 that reaches the sluice 40 that is a waste water treatment facility for cooling water. 24 to 26, 31 are check valves.

  The water cooling apparatus main body 10 has a guide pipe (not shown) that allows the rolled material to pass therethrough, and the guide pipe is filled with cooling water for cooling the rolled material. A large amount of cooling water is allowed to flow through the induction pipe, and the rolling material is passed through the induction pipe filled with the cooling water. The water-cooling device body 10 has a structure capable of supplying a large amount of cooling water without mixing air bubbles that hinder cooling by supplying water from both ends of the induction pipe toward the inside and draining at the center. It has become.

  By the way, in the case of strip rolling, when the leading end of the rolled material enters the induction pipe in a state where the cooling water is filled in the induction pipe, the leading end of the rolled material is extremely cooled, and the next finishing rolling mill row 70 Cause inadequate roll biting and roll damage in the first rolling mill. Further, in the case of a thin rolled material, the cooling water may become resistance and the tip portion may buckle. Therefore, when the end of the rolled material passes through the outlet side end (the outlet side end of the induction pipe) of the water cooling apparatus main body 10 or reaches the position immediately before the outlet side end, the water cooling apparatus main body 10 is supplied by the cooling water supply line 20. Cooling water is supplied to the tank.

  That is, in the water cooling apparatus configured as described above, conventionally, cooling water supply control has been performed as follows.

  When the rear end of the rolled material passes through the outlet end of the water cooling apparatus main body 10, the water supply to the water cooling apparatus main body 10 is stopped by switching the three-way valve 23, and the cooling water from the cooling water supply source is caused to flow through the bypass line 30. ing. In this case, the controller (PI adjustment) is performed so that the measured value of the cooling water flow rate by the flow meter 21 becomes a predetermined flow rate setting value Qs when the cooling water is supplied to the water cooling apparatus main body 10 by the cooling water supply line 20. 50), the opening degree of the flow rate adjusting valve 22 is adjusted.

  Next, when the next rolled material is guided and the leading end of the rolled material passes through the outlet side end 10a of the water cooling apparatus main body 10, or when it reaches the position immediately before the outlet side end, by switching the three-way valve 23, Cooling water from the cooling water supply source flows through the cooling water supply line 20 and is supplied to the water cooling apparatus main body 10. In this case, the opening adjustment of the flow rate adjustment valve 22 by the regulator 50 is performed so that the measured value of the coolant flow rate by the flow meter 21 becomes the flow rate set value Qs. Then, when the rear end of the rolled material passes through the outlet end of the water cooling apparatus main body 10, the water supply to the water cooling apparatus main body 10 is stopped by switching the three-way valve 23, and the cooling water supply source is again supplied to the bypass line 30. The cooling water from the water is made to flow.

However, in the above-described conventional cooling water supply control, when the three-way valve 23 is switched, the cooling water is stopped from flowing to the bypass line 30 and is supplied to the cooling water supply line 20 to be supplied to the water cooling apparatus main body 10. The difference between the pressure loss of the bypass line 30 and the pressure loss of the cooling water supply line 20 causes a large difference in the opening degree of the flow rate adjusting valve 22 before and after the switching of the three-way valve 23, so the water amount immediately after the switching is the target set water amount Different from Qs. The deviation is reduced by the adjuster 50 so that the cooling water flow rate supplied to the water cooling apparatus main body 10 becomes the flow rate set value Qs. However, if adjustment is made so as not to cause hunting, it takes time to converge. It was. For this reason, there was a concern of adversely affecting product quality in controlled rolling.
Japanese Unexamined Patent Publication No. 2007-160316 (FIG. 1)

  Therefore, the problem of the present invention is to provide a cooling water supply line that has a flow meter, a flow rate adjustment valve, and a three-way valve to connect the cooling water supply source and the water cooling device main body, and a bypass line branched from the three-way valve. Each time the rolled material is introduced from the upstream side in the water cooling device of the provided steel strip rolling facility, the three-way valve switches from the bypass line to the cooling water supply line and cools to the water cooling device body for cooling the rolled material. When supplying water, after switching the three-way valve, the cooling water flow rate supplied to the water cooling device main body can be quickly set to the flow rate setting value. Is to provide.

  In order to solve the above problems, the present invention takes the following technical means.

  The invention of claim 1 is installed between the upstream and downstream rolling mill rows of the strip rolling equipment or downstream of the finishing rolling mill row, and the cooling material passes through the inside to cool the rolled material. A water cooling apparatus main body into which water is introduced, a cooling water supply line having a flow meter, a flow rate adjusting valve, and a three-way valve in order from the upstream side to connect the cooling water supply source and the water cooling apparatus main body; and the three-way valve In the cooling water supply control method in the water cooling device of the strip rolling equipment provided with a bypass line branching from, the flow rate setting value of the cooling water flowing to the water cooling device main body by the cooling water supply line for each rolling condition in advance and The data table which defined the opening degree command value of the said flow control valve corresponding was created, (a) The opening degree command value in the said rolling conditions from the said data table for the opening degree command value of the said flow control valve On the other hand, the flow rate control By turning off the opening adjustment of the valve and switching the three-way valve, flowing cooling water through the bypass line, (b) when the rolling material tip has passed the outlet end of the water cooling device body, or When reaching a predetermined position just before the outlet side end, switching of the three-way valve causes the cooling water to flow through the cooling water supply body through the cooling water supply line, (c) the three-way in the step (b) After a predetermined time elapses after switching the valve, the cooling water flow rate flowing through the cooling water supply line based on the measured cooling water flow rate by the flow meter becomes the cooling water flow rate setting value under the rolling conditions. (D) turning off the opening adjustment of the flow rate adjusting valve immediately before the rear end of the rolled material passes through the outlet side end of the water cooling device body, and , Then open Holding the command value in the flow rate adjustment valve; (e) when the rear end of the rolled material passes through the outlet side end of the water cooling device main body, the step of (d) is performed on the flow rate adjustment valve by switching the three-way valve. Including flowing the cooling water through the bypass line in the state where the opening command value held in step 1 is applied as it is, and (f) continuing to the next rolled material and returning to the step (b). It is the cooling water supply control method in the water cooling apparatus of the strip rolling equipment characterized by this.

  Invention of Claim 2 is the cooling water supply control method in the water cooling apparatus of the strip rolling equipment according to Claim 1, wherein the data table is based on the held opening command value output obtained in the step (d). The corresponding opening degree command value is replaced and updated.

  The cooling water supply control method in the water cooling device of the strip rolling equipment of the present invention cools the rolled material by switching from the bypass line to the cooling water supply line with a three-way valve each time the rolled material is introduced from the upstream side. When the cooling water is supplied to the main body of the water cooling system, the three-way valve is switched so that there is no large opening fluctuation of the flow control valve due to the difference between the pressure loss of the bypass line and the pressure loss of the cooling water supply line. Thereafter, the flow rate of the cooling water supplied to the main body of the water cooling device can be quickly set to the flow rate set value. Therefore, it is possible to avoid a decrease in product quality due to controlled rolling.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the last rolling mill 60 a of the intermediate rolling mill row 60 on the upstream side of the water cooling apparatus main body 10 is provided with a metal-in detector 61 that detects whether or not the rolled material is caught. Yes. In the present embodiment, a metal-in signal is output from the metal-in detector 61 when the rolled material reaches the rolling mill 60a, and a timer is provided that starts timing in response to the metal-in signal. Here, since the rolling speed of the rolling material by the rolling mill rows 60 and 70 is determined in advance, the water cooling device enters the water cooling device main body 10 from the intermediate rolling mill row 60 according to the time counted by the timer, and further the water cooling device. The position of the rolled material passing through the main body 10 can be tracked.

  FIG. 2 is a flowchart showing a control procedure of the cooling water supply control method according to the present invention which is carried out in the water cooling apparatus shown in FIG. The control procedure of the cooling water supply control method according to the present invention will be described with reference to FIGS.

  First, in advance, for each rolling condition (C1 to Cn), the flow rate setting values (Qs1 to Qsn) of the cooling water to be supplied to the water cooling apparatus main body 10 through the cooling water supply line 20 and the opening command values of the flow rate adjusting valves corresponding thereto ( A data table defining Vs1 to Vsn) is created.

  Next, when the rolling condition Ci is determined, the opening command value of the flow rate adjusting valve 22 is set to the opening command value Vsi corresponding to the cooling water flow rate setting value Qsi in the rolling condition Ci from the data table. The opening adjustment of the flow rate adjusting valve 22 by the regulator 50 is turned off (the opening command value of the flow rate adjusting valve 22: Vsi), and the cooling water is caused to flow through the bypass line 30 by switching the three-way valve 23 (step 101). ).

  Next, when the leading end of the rolling material from the intermediate rolling mill row 60 reaches a position immediately before the preset outlet side end of the water cooling apparatus main body 10 (YES in step 102), the cooling water supply line is switched by switching the three-way valve 23. The cooling water is caused to flow through the water cooling apparatus main body 10 by 20 (step 103). In this case, the fact that the end of the rolled material has reached the position immediately before the exit end is known from the time measured by the timer. Note that the three-way valve 23 may be switched when the leading end of the rolled material reaches the outlet end 10a of the water cooling apparatus main body 10.

  Then, after the three-way valve 23 is switched to the cooling water supply line 20 side in step 103, after a predetermined time elapses in which a large flow fluctuation immediately after the switching is settled, based on the measured value of the cooling water flow rate by the flow meter 21. The opening degree adjustment of the flow rate adjusting valve 22 by the adjuster 50 is turned on so that the flow rate of the cooling water flowing through the cooling water supply line 20 becomes the cooling water flow rate setting value Qsi under the rolling condition Ci (step 104).

  When the opening degree is adjusted by the adjuster 50, the rolled material advances, and the flow rate adjusting valve 22 is opened by the adjuster 50 when the rear end of the rolled material reaches the position just before the outlet end 10a of the water cooling apparatus body 10. The degree adjustment is turned off, and the opening command value Vsi ′ at that time is held in the flow rate adjustment valve 22 (step 105). Further, the opening command value Vsi 'is updated by replacing the corresponding opening command value Vsi in the data table. Here, the fact that the rear end of the rolled material has reached the position immediately before the exit end is known from the time measured by the timer.

  Then, when the rear end of the rolled material passes through the outlet side end 10a of the water cooling apparatus main body 10, in order to prepare for the entry of the next rolled material, by switching the three-way valve 23, the flow rate adjusting valve 22 is held at the above-mentioned step 105. The cooling water is allowed to flow through the bypass line 30 in a state where the degree command value Vsi ′ is applied as it is (opening adjustment is in the off state) (step 106). Here, the passage of the rear end 10a at the rear end of the rolled material is known from the time measured by the timer.

  Next, in general, the process returns to step 2 in preparation for the subsequent entry of the next rolled material under the same rolling condition Ci (YES in step 107).

  That is, when the leading end of the rolling material from the intermediate rolling mill row 60 reaches a position immediately before the preset outlet end of the water cooling apparatus main body 10 (YES in step 102), the process proceeds to step 103, and the three-way valve 23 is switched. Then, the cooling water is supplied to the water cooling apparatus main body 10 through the cooling water supply line 20. At this time, the opening command value of the flow rate adjusting valve 22 is the held opening command value Vsi ′ obtained by water cooling of the rolled material at the previous rolling.

  Then, the process proceeds to step 104, where the controller 50 adjusts the flow rate of the coolant flowing through the coolant supply line 20 based on the measured value of the coolant flow rate by the flowmeter 21 to the cooling water flow rate setting value Qsi under the rolling condition Ci. The opening degree of the flow rate adjustment valve 22 is adjusted by the above.

  In this case, since the opening degree command value Vsi ′ obtained by water cooling of the rolling material at the time of the previous rolling is given to the flow rate adjustment valve 22 as the opening degree command value at the start of the opening degree adjustment, the water cooling device main body The flow rate of the cooling water supplied to 10 can quickly become the flow rate set value Qsi.

  As described above, the cooling water supply control method according to the present embodiment switches the bypass line 30 from the bypass line 30 to the cooling water supply line 20 with the three-way valve 23 each time the rolled material is introduced from the upstream side. When supplying the cooling water, since the large opening degree fluctuation of the flow rate adjusting valve 22 due to the difference between the pressure loss of the bypass line 30 and the pressure loss of the cooling water supply line 20 is prevented, after switching the three-way valve 23, The flow rate of the cooling water supplied to the water cooling apparatus main body 10 by the cooling water supply line 20 can be quickly set to the flow rate set value. Therefore, it is possible to avoid a decrease in product quality due to controlled rolling. In addition, since the data table is updated each time the cooling water is supplied to the water cooling apparatus main body 10, the latest set value can be used when the rolling conditions are frequently changed. It is also possible to cope with fluctuations over a long span such as fluctuations in the source pressure at the water supply source. In the present embodiment, the water cooling device main body 10 is installed between the rolling mill rows 60 and 70. However, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to those installed on the side.

It is a figure which shows roughly the structure of the water-cooling apparatus installed between the intermediate rolling mill row | line | column and finish rolling mill row | line | column in a strip rolling mill. It is a flowchart which shows the control procedure of the cooling water supply control method by this invention implemented in the water cooling apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Water-cooling apparatus main body 20 ... Cooling water supply line 21 ... Flow meter 22 ... Flow control valve 23 ... Three-way valve 30 ... Bypass line 40 ... Sluice 50 ... Controller 60 ... Intermediate rolling mill row 61 ... Metal-in detector 70 ... Finish Rolling mill row

Claims (2)

A water-cooling device installed between the upstream and downstream rolling mill rows of the strip rolling equipment or downstream of the finishing rolling mill row, through which the rolled material passes and cooling water is introduced to cool the rolled material. A main body, a cooling water supply line that has a flow meter, a flow rate adjustment valve, and a three-way valve in order from the upstream side to connect the cooling water supply source and the water cooling device main body, and a bypass line that branches from the three-way valve In the cooling water supply control method in the water cooling device of the provided strip rolling equipment,
In advance, for each rolling condition, create a data table that defines the flow rate setting value of the cooling water flowing to the water cooling device main body by the cooling water supply line and the opening command value of the flow rate adjustment valve corresponding thereto,
(A) While setting the opening command value of the flow rate adjusting valve as the opening command value under the rolling condition from the data table, the opening adjustment of the flow rate adjusting valve is turned off, and the three-way valve is switched. To flow cooling water through the bypass line,
(B) When the rolling material tip passes through the outlet side end of the water cooling device main body or when it reaches a predetermined position immediately before the outlet side end, by switching the three-way valve, the cooling water supply line Flowing cooling water through the water cooling device,
(C) After a predetermined time has elapsed since switching the three-way valve in the step (b), the flow rate of the cooling water flowing through the cooling water supply line is determined based on the measured value of the cooling water flow rate by the flow meter. Turning on the opening adjustment of the flow rate adjustment valve so as to be the cooling water flow rate setting value under rolling conditions;
(D) Immediately before the rear end of the rolled material passes through the outlet end of the water cooling apparatus body, the opening adjustment of the flow rate adjustment valve is turned off, and the opening degree command value at that time is held in the flow rate adjustment valve. Letting
(E) When the rear end of the rolled material passes through the outlet end of the main body of the water cooling device, the opening command value held in the step (d) is given to the flow rate adjustment valve as it is by switching the three-way valve. Flowing cooling water through the bypass line in a state;
(F) Next, in preparation for the next rolled material, returning to the step (b),
The cooling water supply control method in the water cooling apparatus of the strip rolling equipment characterized by including.   The steel bar rolling facility according to claim 1, wherein the opening degree command value obtained in the step (d) is updated by replacing the corresponding opening degree command value in the data table. A cooling water supply control method in a water cooling apparatus.

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