A method for automatically synchronizing the billet linear speed of a tandem rolling mill with the linear speed of a roller bed

Abstract

The application discloses a kind of tandem rolling mill billet linear velocity and roll linear velocity automatic synchronization control method, comprising: installing high-precision Doppler speed measuring length instrument at rolling mill inlet and outlet;Doppler speed measuring length instrument is fed back standard AB pulse signal to the FM450 high-speed counter template of the first PLC installation, and the special speed measuring function block for the instrument is prepared, and the relevant parameters of Doppler length measuring instrument are called and configured in the first control program;By comparing the feedback speed v1' and the original roll setting speed v1, the calculation result is coefficient K;Again, the speed value that the roll should be set actually can be obtained by multiplying coefficient K by the original roll setting speed v1.The application synchronizes billet linear velocity and roll linear velocity, reduces a large amount of friction generated by billet and roll due to different speeds, reduces the frequency of worker grinding roll and maintenance time, improves production efficiency and product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation control technology, in particular to a method for automatically synchronizing the billet linear speed and the roller linear speed of a tandem rolling mill. BACKGROUND

[0002] A large number of work roller tables and extension roller tables are distributed in front of and behind the tandem rolling mill, which are used for the functions of biting and conveying the billets.

[0003] In theory, the movement speed of the billet and the linear speed of the roller should be synchronized during the rolling process (billet speed V1 = roller speed V2), but in actual production, the billet speed and the roller speed are out of synchronization due to various factors (billet speed V1 ≠ roller speed V2).

[0004] The speed calculation in the program is shown in the following formula. Figure 1

[0005] The speed of the roller is followed by the speed of the main drive.

[0006] Main drive linear speed V1 (m / s) = D x π x n / (m / 60)

[0007] D - diameter of the work roll

[0008] n - angular speed of the roll

[0009] V2 roller linear speed (m / s) = D x π x n / 1000 (m / 60)

[0010] D - diameter of the roller

[0011] n - angular speed of the roller

[0012] From the above two formulas, it can be seen that the linear speed of the main drive is calculated based on the roll diameter, while in actual production, the work roll diameter in the rolling schedule is often not very accurate due to the adjustment of micro-tension, calibration and other reasons, and the speed of the roller is given according to the rolling speed in the rolling schedule, which will cause the roller speed and the actual billet speed to be not completely matched.

[0013] The out-of-synchronization of the actual billet speed and the roller speed has the following effects:

[0014] Wax sticking and nodular phenomenon often occur on the roller tables near the front and back of the rolling mill, causing quality accidents such as scratching, in order not to affect the product quality, maintenance workers need to manually polish the surface of the roller table frequently, which not only wastes a lot of manpower and production effective time but also reduces the service life of the roller. The out-of-synchronization of the roller and the rolled billet will affect the width of the rail running surface and the direction of the walking position of the rolled steel after the rolling mill, directly affecting the product quality of the rolling enterprise. ​

[0015] Advantages and disadvantages compared to other control methods:

[0016] A handheld tachometer is used to measure the speed of the steel billet, and the roller conveyor speed coefficient K is calculated manually based on the measurement data.

[0017] Disadvantages: Handheld speed measuring devices are not accurate and can only be used as reference speeds, which is not effective and cannot meet the needs of the field.

[0018] The speed is calculated by the time it takes for the billet to pass through the material tracker, such as Figure 2 As shown:

[0019] The billet's speed (v = s ÷ t) is calculated by taking the time it takes for the billet to pass through material trackers 1 and 2.

[0020] shortcoming:

[0021] The billet speed varies considerably: the billet switches between bite speed, rolling speed, and exit speed, so the calculated speed is only the average of these three speeds.

[0022] The calculated billet speed is not accurate enough: the accuracy of speed calculation depends on the accuracy of time measurement and the distance between the sensor and the time measurement. As the measurement errors in time and distance increase, the accuracy of the speed calculation will also be affected.

[0023] Dependence on sensor and CPU processing speed: Sensor malfunction or improper installation, as well as uncertainty in CPU scanning time, can easily lead to speed calculation errors.

[0024] It is easily affected by external interference: environmental factors such as temperature, humidity, and water vapor may affect the speed calculation, resulting in inaccurate speed calculation. Summary of the Invention

[0025] To improve product quality, enhance brand value, reduce roller wear, decrease spare parts procurement costs, and lower production costs, the present invention aims to provide an automatic synchronization control method for the billet linear speed and roller linear speed of a tandem rolling mill. By synchronizing the billet linear speed and roller linear speed, the large amount of friction caused by the speed difference between the billet and the roller is reduced, thereby reducing the frequency of roller grinding by workers and maintenance time, and improving production efficiency and product quality.

[0026] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0027] This invention discloses an automatic synchronization control method for the billet linear speed and roller conveyor linear speed of a tandem rolling mill, comprising:

[0028] (1) Install high-precision Doppler velocity and length measuring instruments at the inlet and outlet of the rolling mill;

[0029] (2) The Doppler speed measuring and length measuring instrument feeds back the standard AB pulse signal to the FM450 high-speed counter template installed in the first PLC, a special speed measuring function block is prepared for the instrument, and the related parameters of the Doppler speed measuring and length measuring instrument are called and configured in the first control program.

[0030] (3) The feedback speed v1' and the original roller setting speed v1 are compared, and the calculation result is the coefficient K; the actual speed value that the roller should be set to is obtained by multiplying the original roller setting speed v1 by the coefficient K; if the calculation result K exceeds the predetermined range, the coefficient K is automatically assigned as "1", that is, the roller running speed is set as the speed in the rolling table.

[0031] Further, the Doppler speed measuring and length measuring instrument has a measurement precision of 10 pulse numbers per millimeter.

[0032] Further, a feedback and automatic synchronization control program is prepared in the Doppler speed measuring instrument.

[0033] Compared with the prior art, the beneficial technical effects of the present application are:

[0034] (1) Non-contact measurement and high measurement precision can accurately realize the speed measurement of the billet, and real-time feedback to the first control system for control, greatly improving the quality of the product. By using high-precision measuring equipment such as a laser Doppler speed measuring instrument, the matching of the rolling piece and the roller speed can be realized, which can effectively avoid the product distortion face wear exceeding the national standard and the product affected by the roller nodules in the rolling process, and ensure the quality and size precision of the product.

[0035] (2) Realizing the speed matching of the rolling piece and the conveying roller can also improve the service life of the equipment and reduce the procurement cost of spare parts. If the speed of the rolling piece and the conveying roller is not matched, the service life of the roller is short, and it needs to be replaced regularly, which increases the production cost. If the speed is matched, the production efficiency and product quality can be improved, thereby reducing the production cost.

[0036] (3) Benefit analysis:

[0037] ① Quality improvement: The qualified rate of heavy rail products is increased from 92.25% to 92.53%. The heavy rail product production of Baotou Rail and Beam Plant is 600,000 tons per year, and 1,008 tons of qualified heavy rail products can be produced, with an economic benefit of 504,000 yuan.

[0038] ② Reduction of equipment procurement cost: The roller consumption is reduced from 900,000 yuan per year to 65,000 yuan per year, with an economic benefit of 250,000 yuan.

[0039] The total economic benefit of the two items is 754,000 yuan. BRIEF DESCRIPTION OF DRAWINGS

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] Figure 1 Schematic diagram of the Doppler velocimeter feedback and automatic synchronization control program developed for this invention

[0042] Figure 2 This is a diagram illustrating the speed calculation principle in the original program of the background technology.

[0043] Figure 3 This is a schematic diagram illustrating the speed calculation of the time it takes for a steel billet to pass through a material tracker, as described in the background art.

[0044] Figure 4 This is a schematic diagram of the automatic synchronization control method for the billet linear speed and roller table linear speed of the tandem rolling mill of the present invention;

[0045] Figure 5 for Figure 4 Diagram of the middle and lower end of the outlet;

[0046] Explanation of reference numerals in the attached diagram: 1. CCS universal rolling mill; 2. Work roller conveyor; 3. Steel billet; 4. Conveyor roller conveyor; 5. Doppler speed and length measuring instrument. Detailed Implementation

[0047] A method for automatic synchronization control of billet linear speed and roller conveyor linear speed in a tandem rolling mill includes:

[0048] This practical solution involves installing high-precision Doppler velocity and length measuring instruments at the inlet and outlet of the rolling mill. The instrument's measurement accuracy is 10 pulses per millimeter.

[0049] The Doppler speed and length measuring instrument feeds back standard AB pulse signals to the FM450 high-speed counter module installed in the primary PLC. A dedicated speed measuring function block is developed for this instrument, and the relevant parameters of the Doppler length measuring instrument are called and configured in the primary control program.

[0050] The developed Doppler velocimeter feedback and automatic synchronization control program is based on the following principle: Figure 1 As shown.

[0051] The coefficient K is calculated by comparing the feedback speed v1' with the original roller conveyor set speed v1. Multiplying coefficient K by the original roller conveyor set speed v1 yields the actual speed value that the roller conveyor should be set to. To prevent production disruptions due to tachometer malfunctions, the value of K is kept within a certain range (empirical values ​​need verification). If the calculated result K exceeds the predetermined range, the program will automatically assign the coefficient K a value of "1", meaning the control system will set the roller conveyor running speed to the speed in the rolling schedule.

[0052] Application Cases

[0053] After installing the Doppler velocity measuring length meter in the air-cooled water-cooled temperature control box, the 24V power supply line, the 422 protocol communication line and the standard AB pulse signal line are led to the electrical room through a 10-core shielded twisted pair line. In the electrical room, the device is powered by a 24V power supply, the AB pulse signal line is connected to channel 0 of the FM450-1 template, the signal type of the FM450-1 template is configured in the first-level PLC configuration and downloaded to the PLC, the obtained data is put into the corresponding parameters by programming, and the function of calculating the speed of the steel billet is put into the OB36 for fixed scanning period cyclic call. Then the length value, speed value and K coefficient obtained are displayed on the WINCC control interface for the convenience of the operator to view.

[0054] The developer can directly read the data of the speed measuring instrument by introducing the 422 signal of the electrical room through the 422 to USB data line and can debug the device parameters and precision. Such an embodiment can not only be directly connected to the PLC control system, but also can be used for real-time debugging of the device to perfect the functions of the whole system.

[0055] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for automatically synchronizing the speed of billets in a tandem rolling mill with the speed of a roller table, characterized by, Comprise: (1) install high-precision Doppler speed measuring instrument at the entry and exit of rolling mill; (2) the Doppler speed measuring instrument feeds back standard AB pulse signal to the FM450 high-speed counter template installed by first-stage PLC, and a special speed measuring function block is prepared for the Doppler speed measuring instrument, the related parameters of the Doppler speed measuring instrument are called and configured in the first-stage control program; (3) the feedback speed v1' and the original roller setting speed v1 are compared, the calculation result is coefficient K; the actual speed value that the roller should be set is obtained by multiplying the original roller setting speed v1 by the coefficient K; if the calculation result K exceeds the predetermined range, the program will automatically assign the coefficient K as "1", that is, the control system sets the roller running speed as the speed in the rolling table.

2. The method of automatic synchronization of billet line speed and roll table line speed of a tandem rolling mill according to claim 1, characterized in that, The measurement accuracy of the Doppler speed measuring instrument is 10 pulse numbers per millimeter.

3. The method of automatic synchronization of billet line speed and roll table line speed of a tandem rolling mill according to claim 1, characterized in that, The feedback and automatic synchronization control program is prepared in the Doppler speed measuring instrument.

Images