JP2000107804A - Method for deciding cutting length of bar steel and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide an intermediate cutting length including an appropriate surplus length in the case of executing the intermediate cutting before finish rolling. SOLUTION: This device is provided with a temp. sensor 11 for detecting the temp. of bar steel before the intermediate cutting, roll gap measuring apparatus 12, 13 for respectively detecting the gap length of rolling rolls in a roughing mill and finishing mill and cutting length arithmetic unit 22 (cutting length arithmetic part 226) for calculating the intermediate cutting length based on the length of a main body, temp. detected with the temp. sensor 11 and gap lengths respectively detected with the roll gap measuring apparatus 12, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining a cutting length of a steel bar, such as a hot steel bar, which is to be cut before cooling so as to be within a length range required as a product after cooling. A method and an apparatus therefor.

[0002]

2. Description of the Related Art FIG. 5 is a schematic view showing a part of a rolling equipment for strip steel 1. The rolling equipment for strip steel 1 is provided with a rough rolling mill 2 for roughly rolling a lump of steel as a raw material heated to a predetermined temperature by a heating furnace (not shown) to a predetermined sectional dimension before finish rolling.
And a finish rolling mill 4 for finish-rolling the bar steel 1 after the rough rolling to a finished cross-sectional dimension, and cutting the bar steel 1 after the finish rolling to a length based on facility restrictions of a cooling floor 6 which is a post-process facility (intermediate cutting). )
A first cutting machine 5, a cooling floor 6 that naturally cools the bar steel 1 after the intermediate cutting, and a shearing machine 7 that shears several bar steels 1 cooled to a predetermined temperature in the cooling floor 6 to a predetermined size. The steel bar 1 is processed while being conveyed in the direction indicated by the arrow in FIG.

In some cases, a second cutting machine 3 having a higher cutting ability than the first cutting machine 5 is provided between the rough rolling mill 2 and the finishing rolling mill 4. This is because cutting was conventionally performed by the first cutting machine 5, but with the recent demand for higher strength of the steel bar 1, it has become difficult to cut the first cutting machine 5 effectively. The first cutting machine 5 is left as it is, and a new second cutting machine 3 is provided between the rough rolling mill 2 and the finishing mill 4 in consideration of installation space.

[0004] Therefore, depending on the type of steel and the cross-sectional dimensions of the bar steel 1, one of the first and second cutting machines 5 and 3 is used,
Recently, the demand for operating the second cutting machine 3 has been increasing.

FIG. 6 is a sectional view showing a state in which the second cutting machine 3 performs intermediate cutting, in the process of manufacturing the bar steels 1a to 1e.
FIG. 4 is an explanatory view for explaining a change in length of a steel bar 1;
This shows a state in which a to e are viewed from the side. The bar steel 1a as a raw material heated in the heating furnace is roughly rolled to a predetermined cross-sectional shape and a predetermined cross-sectional size by a rough rolling mill 2, and is elongated like a bar steel 1b.

[0006] The bar steel 1b is intermediately cut to a predetermined length by the second cutting machine 3 to form bar steels 1c, 1c, ..., and then is finish-rolled by the finishing mill 4 to obtain bar steels 1d, 1d.
1d, etc., each become longer. And the first cutting machine 5
Are conveyed to the cooling floor 6 without being cut, and at this cooling stage, the steel bars 1d, 1d,.

[0007] Several of these bar steels 1d, 1d, ... are collectively sheared to a predetermined product length by a shearing machine 7, and each bar steel 1d is divided into bar steels 1e, 1e, .... Since the temperature of the sheared steel bars 1e, 1e, ... is usually several hundred degrees Celsius, the steel bar 1e cooled to room temperature when the product is delivered after shearing.
, 1e, ... are further contracted and shortened.

In such a rolling plant, the length of the bar steel 1e, 1e,... As a product is given by the main body length at room temperature and its tolerance required by the product delivery destination. The length of the steel bars 1e, 1e,... Does not fall below the required length of the main body and cannot be shipped as a product, and the steel bars 1e, 1e,.
It is important to determine the cutting length of the intermediate cutting including an appropriate surplus length so that the length does not greatly exceed the main length and lower the yield.

[0009]

However, the extra length in the cutting length as described above has been conventionally determined manually. For this reason, when performing intermediate cutting after finish rolling, it is easy to determine the extra length only by taking into account that it is cooled to room temperature and then contracted, but it is easy to perform intermediate cutting before finish rolling. In the case of implementation, it is necessary to further consider the length that changes in finish rolling (the “extension length” that changes from bar 1c to 1d in FIG. 6) to determine the extra length.
It was difficult to determine the extra length.

The present invention has been made in view of such circumstances, and detects the temperature of a strip before intermediate cutting and the gap length between rolling rolls in a rough rolling mill and a finishing rolling mill, respectively. And, by determining the intermediate cutting length based on the subject length, in the case of performing the intermediate cutting before finish rolling, a strip steel cutting length determining method capable of determining an intermediate cutting length including an appropriate extra length And an apparatus therefor.

[0011]

According to a first aspect of the present invention, there is provided a method for determining a cutting length of a steel bar, wherein the length of the steel bar after finish rolling is set to a predetermined length. A method for determining a strip steel cutting length, the step of detecting a temperature of the strip steel before cutting, and a gap length between rolling rolls in the rough rolling mill and the finish rolling mill, respectively, the predetermined length, the temperature, and Calculating the cutting length based on the gap length.

[0012] A method for determining a cutting length of a bar according to a second invention is a method for determining a cutting length for cutting a bar between a rough rolling mill and a finishing rolling mill so that the strip after finishing rolling has a predetermined length. A determining method, wherein the step of detecting the gap length between the rolling rolls in the rough rolling mill and the finish rolling mill, respectively, the rolling by the rough rolling mill and the finish rolling mill based on the detected gap length. Calculating the cross-sectional area of the section steel, detecting the temperature of the section steel before cutting, and calculating the allowable width of the predetermined length based on the detected temperature, gap length, and steel type of the section steel, respectively. And calculating the cutting length based on the cross-sectional area, the temperature, the allowable width, and the heat shrinkage of the steel bar.

[0013] A method for determining a strip length according to a third invention is the method for determining a strip length according to the first or second aspect, wherein the step of detecting the length of the strip after the finish rolling is performed; The method further includes a step of calculating a deviation between the cut length and the calculated value, and a step of correcting the cut length based on the calculated deviation.

[0014] A method of determining a strip length according to a fourth aspect of the present invention is the method of determining a strip length according to the third aspect, wherein the correcting step stores the calculated cut length and deviation in time series. The method further comprises the step of correcting the calculated cut length based on the calculated deviation, and the calculated deviation, and a ratio of the calculated cut length to a previously calculated cut length.

According to a fifth aspect of the present invention, there is provided a strip steel cutting length determining apparatus for determining a cutting length for cutting a strip between a rough rolling mill and a finish rolling mill in order to set the strip after finish rolling to a predetermined length. A determining device, a temperature detector for detecting a temperature of the strip steel before cutting, a gap length detector for detecting a gap length between rolling rolls in the rough rolling mill and the finish rolling mill, respectively, Cutting length calculating means for calculating the cutting length based on the temperature detected by the temperature detector and the gap length detected by the gap length detector, respectively.

According to a sixth aspect of the present invention, there is provided an apparatus for determining a cutting length of a steel bar between a rough rolling mill and a finishing rolling mill so as to set the length of the steel bar after finish rolling to a predetermined length. A determination device, wherein a gap length detector for detecting a gap length between rolling rolls in the rough rolling mill and the finish rolling mill, respectively, and the rough rolling based on the gap length detected by the gap length detector, respectively. Cross-section calculating means for calculating the cross-sectional area of each of the strips to be rolled by a mill and a finishing mill, a temperature detector for detecting the temperature of the strip before cutting, and the temperature detected by the temperature detector. An allowable width calculating unit that calculates the allowable width of the predetermined length based on the gap length detected by the gap length detector and a steel type of the strip steel, and the cross-sectional area calculated by the cross-sectional area calculating unit. Cutting length calculating means for calculating the cutting length based on the area, the temperature detected by the temperature detector, the allowable width calculated by the allowable width calculating means, and the heat shrinkage of the strip. It is characterized by.

According to a seventh aspect of the present invention, there is provided the strip length determining apparatus according to the fifth or sixth aspect, wherein the length detecting means for detecting the length of the strip after the finish rolling is provided. Deviation calculating means for calculating a value relating to the length detected by the means and a deviation of the cutting length calculated by the cutting length calculating means; and the cutting based on the deviation calculated by the deviation calculating means. And a correcting means for correcting the length.

According to an eighth aspect of the present invention, there is provided the strip length determining apparatus according to the seventh aspect, wherein the cut length calculated by the cut length calculating means and the deviation calculated by the deviation calculating means are determined. Storage means for storing in time series, wherein the correction means comprises a ratio of the cutting length calculated by the cutting length calculating means and a cutting length calculated by the cutting length calculating means, and the deviation The apparatus is characterized in that the cutting length calculated by the cutting length calculating means is corrected based on the deviation calculated by the calculating means.

The principle of determining the cutting length of the strip according to the present invention will be described below. In the rolling equipment for strip steel, pass detectors for detecting the passage of the strip are provided on the entrance side of each rolling mill, each cutting machine, cooling floor, shearing machine, and the like. Based on the results, tracking of the bar is performed. In the tracking information, information such as the type of steel bar and the length of the main body is stored.

In the method and apparatus for determining the cutting length of a strip according to the present invention, the tracking information includes a gap length (hereinafter referred to as a roll gap) between rolling rolls in a rough rolling mill and a finishing rolling mill, which will be described later. The length operation value and the actually measured value are additionally recorded and stored.
Therefore, for example, the passage of the steel bar is detected by the above-described passage detector provided in the rough rolling mill on the upstream side of the second cutting machine,
At this point, the intermediate cutting length is calculated.

In the calculation, first, the steel type, main length, and roll gap of the bar steel stored in the tracking information are obtained, and whether or not these are the same as the steel type, main length, and roll gap in the previous calculation. Check. That is, if all these conditions are the same, the same cutting length can be obtained by the following equation (1), so that the subsequent calculation of the cutting length can be omitted. On the contrary, if any of the above conditions is different, it is necessary to newly calculate the cutting length using the equation (1).

[0022] _{L i = γ · T i ·} n · (L + α) · S i / SO i (1) L i: intermediate cut length (m) gamma: linear expansion coefficient (deg ^-1) T _i: Before intermediate cut N: Number of samples (pieces) L: Subject length (m) α: Allowable width (m) SO _i : Cross-sectional area of steel bar in rough rolling mill (mm ² ) S _i : Steel bar in finishing mill Cross-sectional area (mm ² )

However, the number of samples is the number obtained when the bar after the intermediate cutting is sheared into a plurality of bar lengths as products, and is set in advance. In addition, it is also possible to adopt a configuration in which the information on the number of samples is input in advance and included in the tracking information. The allowable width is the width of the allowable difference with respect to the main length, and is obtained in advance based on the temperature of the steel bar at the time of shearing, the steel type, the main length, and the like. In addition, the cross-sectional areas of the bar steel in the rough rolling mill and the finish rolling mill can be calculated from the roll gaps of the rough rolling mill and the finishing rolling mill described above.

On the other hand, when the steel type, main length and roll gap of the bar steel stored in the tracking information are the same as the steel type, main length and roll gap at the time of the previous calculation, as described above, the equation (1) is used. There is no need to calculate again.

The actual measured value of the intermediate cutting length is calculated by calculating the intermediate cutting length as shown in the equation (1), and calculating the time required for the intermediately cut strip to reach the length measuring instrument provided downstream of the finishing mill. It can be obtained by making a prediction based on the tracking information and measuring after elapse of this time.

In the method and apparatus for determining a cutting length of a bar according to the present invention, the steel type, the main length and the roll gap of the bar stored in the tracking information are the same as the steel type, the main length and the roll gap at the time of the previous calculation. If they are the same, the next intermediate cutting length is to be corrected based on the actually measured intermediate cutting length as described above.

First, a deviation β _i between the intermediate cutting length calculated as in the equation (1) and the actually measured intermediate cutting length is calculated based on the equation (2).

Β _i = L _i −LH _i (2) β _i : deviation (m) L _i : calculated value of intermediate cutting length according to equation (1) (m) LH _i : measured value of intermediate cutting length (m) )

Therefore, the deviation β _i is the error when the intermediate value is cut with the calculated value as the target value. In the next calculation of the intermediate cut length, the calculation result of the equation (1) is corrected by this amount. Since it is sufficient to add the intermediate cutting length L after the correction,
_i can be calculated by equation (3).

L _i = (L _i−1 −β _i−1 ) · L _i / L _i−1 (3) L _i : Intermediate cutting length after correction (m) L _i−1 : Equation (1) The previous intermediate cutting length (m) β _i-1 : the previous deviation (m)

[0031] Note that in the long products cut length determining method and apparatus according to the present invention that the above description, (2) the length of the long products Found LH _i of the intermediate cutting length used in the formula, which has been cooled to room temperature after shearing Is measured, and a length obtained by multiplying this by the number of samples can be used to obtain a more accurate intermediate cutting length.

Further, as the subject length L used in the equation (1),
For example, when using the length of the bar steel which is higher than the normal temperature immediately after the shearing, an appropriate value can be obtained by calculating the main length L by the equation (4).

L = (L ₁ + α ₁ ) + (L ₂ + α ₂ ) +... + (L _n + α _n ) (4) L _{1 to} L _n : Measured values (m) α _{1 to} α _n : tolerance (m) of the _{1st to nth} bar steels

As described above, the method and the apparatus for determining the cutting length of the strip according to the first, second, fifth and sixth inventions include the temperature of the strip before intermediate cutting, the roll gap of the rough rolling mill and the finish rolling mill. Are detected, respectively, and a predetermined length of the subject length, the temperature,
And calculating the intermediate cutting length based on each roll gap.

More specifically, the roll gaps of the rough rolling mill and the finish rolling mill are detected, and based on the detected roll gaps, the cross-sectional areas of the strips to be rolled in the rough rolling mill and the finish rolling mill are calculated. . Next, the temperature of the bar before the intermediate cutting is detected, and the allowable width for the main length is calculated based on the detected temperature, roll gap, and steel type of the bar. Then, the calculated cross-sectional area, temperature, allowable width,
And calculating the intermediate cutting length based on the heat shrinkage of the strip.

Accordingly, it is possible to determine an intermediate cut length including an appropriate extra length in a strip steel rolling facility for performing intermediate cut before finish rolling.

A method and an apparatus for determining a cutting length of a strip according to the third, fourth, seventh and eighth inventions detect the length of the strip after finish rolling, and determine a value related to the detected length. A deviation from the calculated value is calculated, and the intermediate cutting length calculated as described above is corrected based on the calculated deviation. When the length after shearing is used as described above as the length of the strip after finish rolling, a value obtained by multiplying the number of samples from the strip after intermediate cutting can be used.

More specifically, as the above-described correction, the calculated intermediate cutting length and deviation are stored in a time series like tracking information, and the intermediate cutting length and the intermediate cutting length calculated before that are stored. The calculated intermediate cutting length is corrected based on the ratio and the deviation.

Therefore, the calculated value of the intermediate cutting length is corrected based on the deviation from the actually measured value of the intermediate cutting length actually obtained based on this calculated value. Cutting length can be obtained.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a configuration diagram showing a main part of a rolling facility in which a strip steel cutting length determining apparatus according to the present invention is used. In FIG. 1, rolling equipment for a bar steel 1 such as a bar to be rolled mainly includes a rough rolling mill 2, a second cutting machine 3, a finishing rolling mill 4, a first cutting machine 5, a cooling floor 6, and a shearing machine 7. The bar 1 is processed while being conveyed as indicated by the arrow in FIG.

After the lump of the steel bar 1 as a raw material is heated to a predetermined temperature by a heating furnace (not shown), it is coarsely rolled by a rough rolling mill 2 to a predetermined cross-sectional dimension before finish rolling. 3, the intermediate floor is cut into lengths based on the equipment restrictions of the cooling floor 6, which is a post-process equipment, and is finish-rolled to a finishing cross-sectional dimension by the finishing mill 4, and then transferred to the cooling floor 6 by the roller table 15. Air cooling. The strip steel 1 cooled to a predetermined temperature in the cooling floor 6 is collectively sheared into predetermined dimensions by a shearing machine 7 several times, and then cooled to room temperature to be a product. However, when the second cutting machine 3 is not used, the strip steel 1 after finish rolling is intermediately cut by the first cutting machine 5 for the same purpose.

On the upstream side of the rough rolling mill 2, a temperature sensor 11 for detecting the temperature of the steel bar 1 passing therethrough is provided. In addition, as the temperature sensor 11, in addition to a non-contact type such as a radiation thermometer, a contact type temperature measuring unit such as a resistance thermometer and a thermocouple can be used.

The rough rolling mill 2 and the finish rolling mill 4 are provided with roll gap measuring devices 12 and 13, respectively, to detect the cross-sectional dimensions during the rough rolling and the finish rolling.

Immediately upstream of the cooling floor 6, an intermediate cutting length meter 14 for measuring the length of the strip 1 after the intermediate cutting conveyed to the cooling floor 6 is provided. Is provided with a shear length meter 16 for measuring the length of the bar steel 1 after shearing.

In the vicinity of the entry side of each station such as the rough rolling mill 2, the second cutting machine 3, the finishing rolling machine 4, and the first cutting machine 5, the cooling floor 6, the shearing machine 7, etc. And tracking sensors S, S,... For detecting the transport speed.

FIG. 2 is a block diagram showing the configuration of the steel bar cutting length determining apparatus according to the present invention. This apparatus comprises a temperature sensor 11, roll gap measuring devices 12, 13, an intermediate cutting length meter 14, a shear length meter 16, and tracking sensors S, S,
And the measurement control device 21 connected to the
A cutting length calculating device 22 connected via a communication line to
A cutting control device 23 connected to the cutting length calculating device 22 via a communication line and connected to the second cutting machine 3
It is composed of

The measurement control device 21 includes a cutting length calculation device 22
The measurement timing is predicted based on the tracking information of the steel bar 1 given from the controller, and a measurement instruction signal is sent to the temperature sensor 11, the roll gap measuring devices 12, 13, the intermediate cutting length meter 14, and the shear length meter 16 according to the elapse of the predicted time. Output,
Let each measurement be performed. Further, as the measurement results, the temperature of the bar 1 before rough rolling, the roll gap during rough rolling (rough rolling roll gap), the roll gap during finish rolling (finish rolling roll gap), and the length of the bar 1 after intermediate cutting. The length of the bar 1 after the shearing is received from each measuring device and sent to the cutting length calculating device 22. Also, it receives a tracking signal including the presence / absence of passage of the steel bar 1 detected by the tracking sensors S, S,... And a transport speed, and sends it to the cutting length calculating device 22.

The cutting length calculating device 22 is composed of a process computer and includes a tracking information processing section 221, a tracking information database 222, a transmitting section 223, a receiving section 224, a material / dimensional information database 225, and a cutting length calculating section 226. The transmission unit 223 and the reception unit 224 have a communication function with the measurement control device 21.

The tracking information processing section 221 performs tracking of the steel bar 1 conveyed in each step in FIG. 1 based on the tracking signal from the tracking sensors S, S,. It generates information and outputs a tracking information transmission instruction signal to the transmission unit 223. The generated tracking information is stored in the tracking information database 2
22.

The tracking information database 222
The tracking information provided from the tracking information processing unit 221 is stored. The tracking information is stored in chronological order from one station to the next station as one block, and each block has a customer type such as a steel type of steel bar 1 and a subject head inputted from input means (not shown). The request information is stored, and the cutting length calculation unit 226
Is stored.

The transmitting section 223 reads out tracking information from the tracking information database 222 according to the transmission instruction signal given from the tracking information processing section 221 and sends out the tracking information to the measurement control device 21.

The receiving section 224 receives, from the measurement control device 21, the respective detection results of the temperature sensor 11, the roll gap measuring devices 12 and 13, the intermediate cutting length meter 14, and the shear length meter 16, in addition to the information corresponding to the above-mentioned tracking signal. It receives them and supplies them to the material / dimension information database 225, and outputs a calculation instruction to the cutting length calculation unit 226 in accordance with the reception.

The material / dimension information database 225 stores each measurement result given from the receiving section 224, and also stores a linear expansion coefficient according to the steel type of the bar steel 1, a steel type, a subject length,
A data table is stored which has a tolerance for the main length and the number of samples obtained by shearing the bar 1 after the intermediate cutting, corresponding to the cross-sectional area, the temperature during rough rolling, and the like.

The cutting length calculating section 226 reads necessary information from the data table stored in the material / dimensional information database 225 in accordance with a calculation instruction signal given from the receiving section 224, and reads the necessary information from the tracking information database 222. The tracking information stored in a series is read out, an intermediate cutting length is calculated based on the readout result, and the calculated length is sent to the cutting control device 23.

The cutting controller 23 has a cutting length calculator 226.
The intermediate cutting position of the second cutting machine 3 is set and controlled on the basis of the intermediate cutting length given by the company, and based on the setting result, the steel bar 1 to be conveyed next is intermediately cut.

Note that the measurement control device 21 includes a transmission unit 223
From the tracking information received from the temperature sensor 11, the roll gap measuring devices 12, 13, the intermediate cutting length meter 14, and the shear length meter 16, respectively, predict the time it takes for the same bar 1 to reach, and the predicted time elapses At this point, a measurement instruction is output to each of these measuring instruments.

The apparatus for determining a cutting length of a steel bar according to the present invention has the hardware configuration as described above, and determines the intermediate cutting length in the following procedure.

FIG. 3 is a flowchart showing a procedure for determining an intermediate cutting length of the strip steel cutting length determining apparatus according to the present invention. First, the tracking information processing unit 221 generates tracking information based on a tracking signal or the like from each of the tracking sensors S, S,... (Step 1), and based on the generated tracking information, a time required for the steel bar 1 to reach the temperature sensor 11. Is measured by the measurement control device 21 (Step 2), and after the elapse of the predicted time, the temperature sensor 11 and the roll gap measuring devices 12 and 13 execute each measurement (Step 3).

Based on the measured rough rolling roll gap and finish rolling roll gap, the cutting length calculating section 22 calculates the cross-sectional area of the steel bar 1 expected at the time of rough rolling and finish rolling (step 4). The measurement result of the temperature sensor 11 obtained in step 3, the steel type and main length of the bar 1 described in the corresponding block of the tracking information generated in step 1, and the cutting of the bar 1 during finish rolling in step 4 Based on the area, the cutting length calculation unit 226
The corresponding tolerance is read out from the dimension information database 225 (step 5), and the information obtained in steps 3 to 5 is used to calculate the cutting length based on the equation (1).
Calculates the intermediate cutting length of the above-mentioned bar 1 that has reached the temperature sensor 11 (step 6).

Next, the cross-sectional area calculated in step 4 and the steel type and main length of the bar 1 described in the corresponding block of the tracking information generated in step 1 are
The cutting length calculating unit 226 checks whether or not the sectional area, the steel type, and the main length stored in the previous block of the corresponding block are different (step 7).

If any one of these is different, the measurement controller 21 predicts the time required for the steel bar 1 to reach the intermediate cutting length meter 14 from the tracking information generated in step 1 (step 8), and the predicted time After the time elapses, the intermediate cutting length meter 14 performs the measurement (step 9).

On the other hand, if all of the cross-sectional area, steel type, and main length stored in the previous block correspond to or are within the predetermined range in step 7, the intermediate value calculated in step 6 is used. From the deviation between the calculated value of the cutting length and the actual measured value of the intermediate cutting length measured in step 9, the cutting length calculator 226 calculates the extra length correction amount (deviation) based on the above equation (2) (step). 10) From the calculated extra length correction amount, the cutting length calculating unit 226 further corrects the intermediate cutting length calculated in step 6 based on the above equation (3) (step 11).

After step 9 or 11, the information of the items included in the tracking information among the information obtained in steps 3 to 6, 9, and 11 is used as the cutting length calculating section 226.
Supplies the information to the tracking information database 222 to store them (step 12), and executes the next intermediate cutting based on the intermediate cutting length calculated in step 6 or the intermediate cutting length further corrected in step 11. To this end, the cutting length calculation unit 226 sends any intermediate cutting length to the cutting control device 23 (Step 13), and repeats from Step 2.

FIG. 4 is a table showing a comparison between the result of the determination of the cutting length by the apparatus for determining a cutting length of a steel bar according to the present invention and the result of the determination by the apparatus based on the conventional method. In addition, the bar steel 1 for reinforced concrete is used as the bar steel 1 to be cut, the diameter of which is 60.0 mm, the main length is 60 m, the allowable width at the time of shearing is 15 mm, and the bar steel 1 after the intermediate cutting is obtained by shearing. The number of samples to be collected is 11, and the tolerance is -0.20mm ~
+0.20 mm.

As shown in the table, (remaining length of conventional device)
The surplus length reduction calculated by (the surplus length of the present invention) is 0.12.
1 m, and the ratio of the reduced amount in the indicated value of the intermediate cutting length was calculated as 0.121 m / 66.125 m × 100%, and thus a reduction in the extra length of about 0.18% could be achieved.

[0066]

As described above in detail, in the method and apparatus for determining the cutting length of the strip according to the present invention, the temperature of the strip before the intermediate cutting and the roll gaps of the rough rolling mill and the finish rolling mill are detected, respectively. An intermediate cutting length is calculated based on a predetermined main body length, the temperature, and each roll gap.

More specifically, the roll gaps of the rough rolling mill and the finish rolling mill are detected, and the cross-sectional areas of the strips to be rolled in the rough rolling mill and the finish rolling mill are calculated based on the detected roll gaps. . Next, the temperature of the bar before the intermediate cutting is detected, and the allowable width for the main length is calculated based on the detected temperature, roll gap, and steel type of the bar. Then, the calculated cross-sectional area, temperature, allowable width,
And calculating the intermediate cutting length based on the heat shrinkage of the strip.

Therefore, it is possible to determine an intermediate cut length including an appropriate extra length in a strip steel rolling facility for performing intermediate cut before finish rolling.

Further, the length of the strip after finish rolling is detected,
A deviation between a value related to the detected length and the calculated value is calculated, and the intermediate cutting length calculated as described above is corrected based on the calculated deviation. When the length after shearing is used as described above as the length of the strip after finish rolling, a value obtained by multiplying the number of samples from the strip after intermediate cutting can be used.

More specifically, as the above-mentioned correction, the calculated intermediate cutting length and deviation are stored in a time series like tracking information, and the intermediate cutting length and the intermediate cutting length calculated before that are stored. The calculated intermediate cutting length is corrected based on the ratio and the deviation.

Accordingly, the calculated value of the intermediate cutting length is corrected based on the deviation from the actually measured intermediate cutting length based on the calculated value, so that a more accurate intermediate cutting length can be obtained. The present invention has an excellent effect, for example, a cutting length can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a main part of a rolling facility in which a strip steel cutting length determination device according to the present invention is used.

FIG. 2 is a block diagram showing a configuration of a steel bar cutting length determining device according to the present invention.

FIG. 3 is a flowchart showing an intermediate cutting length determining procedure of the strip steel cutting length determining apparatus according to the present invention.

FIG. 4 is a chart showing a comparison between a cutting length determination result obtained by the strip steel cutting length determining apparatus according to the present invention and a cutting length determination result obtained by an apparatus based on a conventional method.

FIG. 5 is a schematic view showing a part of a strip steel rolling facility.

FIG. 6 is an explanatory view for explaining a change in the length of a bar in the process of manufacturing the bar when intermediate cutting is performed by a second cutting machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Strip steel 2 Rough rolling mill 3 Second cutting machine 4 Finishing rolling mill 5 First cutting machine 6 Cooling floor 7 Shearing machine 11 Temperature sensor 12, 13 Roll gap measuring instrument 14 Intermediate cutting length gauge 16 Shear length gauge 21 Measurement control device 22 Cutting length Arithmetic unit 23 Cutting control unit 221 Tracking information processing unit 222 Tracking information database 226 Cutting length calculation unit

Claims (8)

[Claims] 1. A method for determining a cutting length for cutting a strip between a rough rolling mill and a finishing rolling mill so that the strip after finish rolling has a predetermined length, comprising: Detecting the temperature of the strip steel and the gap length between the rolling rolls in the rough rolling mill and the finishing mill, and calculating the cutting length based on the predetermined length, temperature and gap length, respectively. A method for determining a cutting length of a steel bar. 2. A method for determining a cutting length for cutting a strip between a rough rolling mill and a finishing rolling mill so that the strip after finish rolling has a predetermined length. And detecting the gap length between the rolling rolls in the finish rolling mill, respectively, and calculating the cross-sectional area of the strip steel to be rolled in the rough rolling mill and the finish rolling mill based on the detected gap length, respectively. Detecting the temperature of the bar before cutting; calculating the allowable width of the predetermined length based on the detected temperature, gap length, and steel type of the bar;
Calculating the cut length based on the temperature, the allowable width, and the heat shrinkage of the steel bar. Detecting a length of the strip after the finish rolling; calculating a value related to the detected length and a calculated deviation of the cut length; and calculating the calculated deviation. 3. The method for determining a strip length according to claim 1 or 2, further comprising the step of correcting the cut length based on the following. 4. The step of correcting includes a step of storing the calculated cutting length and deviation in time series, and a step of calculating a ratio of the calculated cutting length and a previously calculated cutting length. Correcting the calculated cutting length based on the deviation. 4. The method according to claim 3, further comprising the step of: 5. A strip steel cutting length determining apparatus for determining a cutting length for cutting said strip between a rough rolling mill and a finishing rolling mill so that the strip after finish rolling has a predetermined length. A temperature detector for detecting a temperature of the strip steel, a gap length detector for detecting a gap length between rolling rolls in the rough rolling mill and the finish rolling mill, respectively,
Cutting length calculating means for calculating the cutting length based on the temperature detected by the temperature detector and the gap length detected by the gap length detector, respectively. apparatus. 6. A steel strip cutting length determining device for determining a cutting length for cutting said steel strip between a rough rolling mill and a finishing rolling mill so that the steel strip after finish rolling has a predetermined length. And a gap length detector for detecting the gap length between the rolling rolls in the finish rolling mill, and the rolling performed by the rough rolling mill and the finish rolling mill based on the gap length detected by the gap length detector, respectively. A cross-sectional area calculating means for calculating a cross-sectional area of the bar steel, a temperature detector for detecting a temperature of the bar steel before cutting, the temperature detected by the temperature detector, and the temperature detected by the gap length detector, respectively. An allowable width calculating means for calculating an allowable width of the predetermined length based on the gap length and a steel type of the steel bar; and a cross-sectional area calculated by the cross-sectional area calculating means, detected by the temperature detector. A cutting length calculating means for calculating the cutting length based on the temperature, the allowable width calculated by the allowable width calculating means, and the heat shrinkage of the steel bar. . 7. A length detecting means for detecting a length of the strip after the finish rolling, a value related to the length detected by the length detecting means, and a value calculated by the cutting length calculating means. 7. The apparatus according to claim 5, further comprising: deviation calculating means for calculating a deviation of the cutting length; and correcting means for correcting the cutting length based on the deviation calculated by the deviation calculating means.
An apparatus for determining a strip length according to the above description. 8. A storage unit for storing the cutting length calculated by the cutting length calculation unit and the deviation calculated by the deviation calculation unit in a time-series manner, wherein the correction unit performs the cutting length calculation. The cutting length calculated by the cutting length calculating means based on the ratio of the cutting length calculated by the means and the cutting length calculated by the cutting length calculating means before that, and the deviation calculated by the deviation calculating means. 8. The strip steel cutting length determining device according to claim 7, wherein the cutting length is corrected.