JPS62224414A - Control method for cooling temperature of rolled stock - Google Patents

Abstract

PURPOSE:To improve the product yield by controlling a coolant flow rate to be constant for a prescribed duration before and after the top of a rolled stock reaches a cooling zone and controlling a coolant flow rate based on a stock temp. in the inlet side of the cooling zone after the above duration. CONSTITUTION:An inlet side steel stock temp. TA is real time measured from the time when a carried inlet side steel stock 10A reaches an inlet side steel stock thermometer 14A and the measured value is sent to a controller 16. Then, a coolant flow rate is controlled to be constant for a prescribed duration by a control valve 26 through an amplifier 22 and a unit 24. The flow rate through the valve 26 is subjected to a feedforward control by a feedforward arithmetic function 18 after the duration. In that method, the temp. throughout the entire length of the stock including the top part is equalized, so that the dimensional accuracy of products is improved and variations in scale are reduced to improve the product yield.

Description

[Detailed description of the invention]

[Industrial Application Field 1 The present invention is suitable for water-cooling wire rods and steel bars during rolling.
The present invention relates to an improvement in a method for controlling the cooling temperature of a rolled material when the rolled material is cooled by supplying a cooling liquid in a cooling zone.

[Prior art] Generally, when rolling steel materials such as wire rods and steel bars, the steel materials are water-cooled upon exiting the finishing mill to facilitate processing in subsequent steps and to reduce the scale of the steel materials. The aim is to suppress the generation of Here, the water cooling process of the steel material during rolling will be explained based on the water cooling control device shown in FIG. The steel material 10 during rolling is
It enters the water-cooling box 12 at a certain rolling speed V, where cooling water is supplied and cooled to a predetermined temperature, and it exits the water-cooling box 12 and proceeds to the water cooling box 12.At this time, the simplest cooling method for the steel material 10 is There is a method in which the cooling water supplied to the steel material 10 in the cooling box 12 is controlled to a constant flow.
A, and the steel material on the exit side is assumed to be the exit side net material 10B, and the following description will be made. This constant flow mother control is performed to reduce the temperature of the inlet steel material 10A measured by the inlet steel material thermometer 14A, while the temperature of the inlet steel material 10A is
This is a control for water cooling by supplying a constant flow of cooling water to the rolled material 10 over the entire length so that the temperature rg and T of the exit net material 10B measured at B are within a predetermined control temperature box. . FIG. 3A shows an example of the relationship between the inlet steel material temperature T^, the cooling water flow ff1Q, and the outlet material temperature T when the cooling of the m material 10 is controlled with a constant flow m in this manner. In addition, in the figure, the temperature T^ of the material between the inlet side i is indicated by the symbol A1, the flow rate Q is indicated by the symbol Q1, and the temperature T of the outlet mesh material T is indicated by the symbol B1. In this case, the range of fluctuation (indicated by the symbol a in the figure) on the day when the temperature of the material for the exit side is determined is determined by the fluctuation of the temperature of the steel material on the entry side, T^, so the range of fluctuation on the day when the temperature of the material on the exit side is exhausted is reduced. There is a limit to how far the steel material 10 can be heated, and it is necessary to soak the steel material 10 in a heating furnace or to reduce fluctuations in the entrance steel material temperature T^ during rolling, which wastes energy and lowers the operating rate. It had the problem of being stored away. In addition, as another method of cooling the steel material 10, the exit side steel material temperature T in FIG. 2 is measured in real time (
There is a method using feedback control, in which the temperature of the steel material on the exit side is measured in real time and the flow of water supplied from the water cooling box 12 is controlled so that the temperature of the steel material on the exit side falls within the controlled temperature range. However, in this feedback control method, the time required for the input steel material 10Δ to pass through the water cooling box 12 and reach the exit steel material thermometer 148 (in the figure, the distance tL÷rolling speed V); The timing of cooling control for the steel material 10 is shifted. Therefore,
Especially when the rolling speed V is slow, it cannot be expected to accurately equalize the temperature over the entire length of the steel material 10, and even with this feedback control method, the humidity control V using a heating furnace etc. is similar to the constant flow m control described above. The problem was that it required countermeasures such as the following. As a means to solve the problems of constant flow m control and feedback control as described above, a feedforward system (feed forward system) which controls the amount of cooling water supplied to the copper material 10 based on the temperature detected at the inlet side of the water cooling box 12 is proposed. Wholesale is possible.In addition,
Techniques related to this feedforward control include a cold 1g1ffl132 control method for rolling wire rods, which was already proposed in Japanese Patent Laid-Open No. 55-106616. In this method, the cooling water injection from the water-cooled zone is converted into a temperature signal detected by a wire temperature sensor installed at the front stage of the water-cooled zone.
I am adjusting the amount. Here, when performing the feedforward control using the cooling equipment shown in FIG. 2, first, the input ff! lltM
The entrance steel material temperature rCiT^ is measured in real time from the instantaneous force u when the material 10A reaches the entrance material thermometer 14A, and the measured value is sent to the controller 16. This controller 16 performs a feed forward calculation t'F (in function II Then, based on the calculation result, the flow control function 20h outputs a control signal, and the control valve 26 is driven by the unit 24 based on the control signal amplified by the universal amplifier 22. 10A is the entry side material thermometer 14
The water cooling control is started from u11 when the water cooling box 12 is reached after a predetermined time (distance LB ÷ rolling speed \l in the figure) after passing through Δ, and the temperature Ts of the outlet m material is maintained at a predetermined value. Keep the temperature within the controlled temperature range. In addition,
In the figure, 28 is a flow meter that detects the flow of cooling water ff1Q. Figure 3 <8') shows the temperature change when feedforward control is performed over the entire length of the lumber 10 in this way.
Shown below. In the figure, the flow mQ is indicated by the symbol Q2, and the exit side steel material temperature Te is indicated by the symbol B2. As can be understood from the figure, the parts other than the tip of the steel material 1o are shown in the same figure (A
) The temperature of the steel material on the exit side T compared to the constant flow control indicated by the symbol B1
It is possible to reduce and smooth the width of fluctuation in the total length of the day (symbol b in the figure). Problems to be Solved by the Invention However, the reference numeral B2 in FIG.
It is understood that the temperature fluctuation at the tip of the steel material 1o is large, and the temperature fluctuation in this part can be reduced by controlling the heating of the steel material 1o using bar force in the heating zone to reduce the fluctuation in the entrance steel material temperature TA. However, it is not a fundamental countermeasure and cannot be completely eliminated. In addition, in the case of water cooling after rolling, the exit side steel material 1 is
If the temperature fluctuation at the tip of 0B is large, scale defects etc. will occur in that part, and when producing a product, it is necessary to cut I and TI at the part where the defect has occurred, resulting in a decrease in yield. There was a problem.

[Purpose of the invention] The present invention has been made in view of the above-mentioned conventional problems, and provides a cooling temperature control method for a rolled material that can make the temperature of the rolled material after cooling uniform over the entire length including the tip. The purpose is to [Means to solve the problem]

In the present invention, when cooling a rolled material during rolling by supplying a cooling liquid in a cooling zone, the gist of the invention is as shown in FIG. For a predetermined period of time after reaching the temperature, the cooling liquid is controlled to a constant flow rate, and the predetermined period of time has elapsed (for wheat, the temperature of the rolled material is measured on the loading side. The above object is achieved by controlling the flow rate of the cooling liquid.

[Effect]

When performing feedforward control as described above, one
For example, a possible reason for the large temperature fluctuation at the tip of the exit steel material 10Δ on the exit wire temperature T day indicated by the symbol B2 in FIG. 3(B) above is due to the cooling water flow ff1Q.
This is the decrease in the flow base Q (indicated by the symbol m in the figure) that occurs at the time of rise when is controlled. The reason for this decrease in flow rate is, for example, in FIG.
Since there is usually an inherent time delay in the temperature signal output from the temperature signal compared to the actual temperature change, the temperature during the rise of the inlet steel material temperature T
This is taken as the true tip temperature of the entry side net material 10A, and due to this, the entry side net material 10A has a temperature between This is because the inlet Mlu temperature T^ outputted from the steel material thermometer 14A does not become the true steel material temperature (that is, it does not become a step response). If the cooling of the rolled material is performed by feedforward control over the entire length as described above, the above-mentioned glue problem will occur.
・The inventors discovered that before the entrance steel material 10A shown in FIG. 2 was transported and reached the water cooling box 12,
A cooling temperature control method has been devised in which the flow rate of the cold liquid is controlled at a constant rate for a predetermined period of time after 0A reaches the water cooling box 12, and the cooled liquid is feedforward controlled from the moment the predetermined time is exceeded. Therefore, according to the present invention, the temperature at the tip of the rolled material to be cooled can be reliably lowered, so that the humidity after cooling can be made uniform over the entire length of the rolled material, including the tip. . [Example 1] Hereinafter, an example of the method for controlling the cooling temperature of a rolled material according to the present invention will be described in detail. This example is based on the wire rods and bar assembly shown in FIG.
The present invention was implemented in a water cooling control device for cooling a steel material 10 such as a billet. The configuration of this embodiment is similar to that of the conventional example, so detailed explanation thereof will be omitted. The effects of the embodiment will be explained below. The entrance steel material 10A is conveyed at a speed ①, and the temperature T△ of the entrance mesh material is measured in real time from the moment when the entrance steel material 10A reaches the temperature 14A. Measured entrance steel temperature T
△ is sent to the controller 16, and is Wiffed by the internal feedforward calculation n, ohi 18 to reduce the cooling water flow.
The supply timing and required flow rate are calculated. Before the input side steel material 10A reaches the water cooling box 12 and after reaching the time t, the controller 16
The control valve 26 is controlled by the universal amplifier 22 and the unit 24 by the control signal output from the internal flow m control function 2o.
is driven to control 211 the flow field of cooling water supplied to the steel material 10 in the cooling box 12 to a predetermined constant flow rate. Then, feedforward control is performed by driving the control valve 26 so that the required flow rate of cooling water calculated by the feedforward calculation function 18 is supplied to the steel material 10 from the period rs exceeding the time 11. In this way, an example of the exit side waste material temperature T day (code B3) when the cooling water flow ff1Q (code Q3) is controlled is shown in the third example.
Shown in Figure (C). From the figure, it can be seen that unlike the constant flow control and full length feedforward control shown in FIG. The outlet material temperature Te is within the range (symbol C in the figure)
It is understood that this includes Note that the constant flow rate control area (time≦
In j+), flow control is not carried out in real time with respect to fluctuations in the input-side refined material thirst T^, but the control is merely to lower the exit-side steel material 4 degrees T on average. The flow at this time ff1
The value of Q may be controlled by measuring q so that it falls within the control temperature range (symbol C in the figure) using the one-node meter 16, or when rolling is carried out continuously during actual operation. , 1st grade steel material 10
The flow to be controlled may be determined by using the actual flow m when cooling the flow. Further, the appropriate value of t1 can be determined according to the rolling speed V of the steel material 10. Furthermore, in the feedforward control range beyond the time t1 (time 1>1+), the entrance wing temperature T
The cooling water flow m can be controlled in real time in response to fluctuations in A, and the outlet steel material temperature Ts can be made more uniform. From what has been described above, if the cooling temperature is controlled by controlling the water particles using the method of the present invention, the control temperature range (marked @b in Fig. 3) when feedforward control is performed over the entire length of the steel material 10 is achieved. In comparison, the control temperature range is smaller (c
<b) It is possible to do so. Therefore, the steel material 10
It is possible to reduce the temperature change over the entire length and make the temperature after cooling uniform. In the above embodiment, as shown in FIG. 2, water cooling control controls the cooling of the steel material 10 with one water cooling box. Although we have given an example of the device, this water cooling box is not limited to a single unit. ! 2
It is clear that the method of the present invention can be used to cool the steel material 10 even when several water cooling boxes are installed in series. Furthermore, in the above embodiments, wire rods and steel materials such as frame j were exemplified as rolled materials, but the rolled materials according to the present invention are not limited to these materials, and the cooling temperature of other rolled materials may be changed. It is clear that the present invention can be employed in controlling. Furthermore, in the embodiment described above, the case where the present invention is implemented with the water cooling control device shown in FIG. It is clear that the present invention is not limited to a cooling device using a cooling liquid shown in (1) and can be applied to other cooling devices that use other cooling liquids. The temperature after cooling can be made uniform over the entire length of the material, including the tip part. Therefore, when the rolled material is water-cooled before rolling, the dimensional accuracy after rolling can be improved by making the temperature uniform over the entire length. When the rolled material is cooled after rolling, it is possible to reduce temperature defects at the tip of the rolled material and reduce the dispersion of scales that appear on the rolled material, thereby increasing the yield of rolled products. In addition, since there is no need to heat the rolled material in a heating furnace and equalize the temperature over its entire length, the fuel consumption can be reduced. It has excellent effects such as

[Brief explanation of drawings]

FIG. 1 is a flowchart illustrating the gist of the present invention, and FIG. 2 is a block diagram including a partial plan view showing the overall configuration of a cooling temperature control device in which the method for controlling the cooling temperature of a rolled material according to the present invention is implemented. The diagram and FIG. 3 are diagrams comparing and showing examples of cooling temperature control of steel materials by the conventional method and the method of the present invention. 10. 10A, 10B... Steel material, 12... Water cooling box, 14A... Person side material thermometer, 14B... Exit side steel material thermometer, 16... So-called "total," 18...- Feedforward calculation function, 20...Flow layer control function, 26...Control valve, 28...Flow meter.

Claims (1)

[Claims] (1) When cooling a rolled material during rolling by supplying a cooling fluid in a cooling zone, the cooling fluid is not used before the tip of the rolled material reaches the cooling zone and for a predetermined period of time after reaching the cooling zone. is controlled to a constant flow rate, and after the predetermined time has elapsed, the flow rate of the cooling liquid is controlled based on the temperature of the rolled material measured at the entrance side of the cooling zone. Method.