CN104324948B - A kind of rougher of hot strip mill process rolled piece width control method - Google Patents

Abstract

The invention provides a method for controlling the width of a rolled piece in the rough rolling process of hot continuous rolling, which includes: obtaining PDI data of hot continuous rolling; determining the total number of rolling passes according to the technical requirements of the rolling plan; The exit thickness, exit width and strip threading speed of the pass; the rough rolling process starts, and the rolling schedule is calculated once and sent to the rolling line equipment; the even-numbered first-pass width is calculated; the odd-numbered second pass is calculated According to the rolling width of each odd-numbered pass and the rolled thickness of each even-numbered pass, the vertical roll opening and the flat roll gap are continuously adjusted to complete hot continuous rolling. The width of the piece is controlled until the end of the hot rolling rough rolling process. The invention can calculate the width after even-numbered passes on-line, can be successfully applied in the width control process of hot continuous rolling and rough rolling, replaces the role of the width measuring instrument, and improves the precision of width control while saving production investment costs .

Description

A method for controlling the width of rolling stock in hot continuous rolling rough rolling process

technical field

The invention belongs to the technical field of rolling process control, and in particular relates to a method for controlling the width of a rolled piece in the rough rolling process of hot continuous rolling.

Background technique

During the production process of hot continuous rolling, the roughing unit is mainly responsible for the width control of the rolled piece, and calculates the width after rolling of each pass through the width mathematical model to ensure that the width of the finished product is within the required range.

At present, in most hot continuous rolling production lines at home and abroad, the rough rolling unit widely adopts the configuration mode of "vertical roll + flat roll" two stands, and adopts the reciprocating rolling strategy with the total number of passes being an odd number of passes. In order to reduce the cost, the rough rolling unit is generally only equipped with a width gauge after the machine, which can only measure the actual width of the rolled piece after the odd-numbered rolling (after the comprehensive control of the vertical roll and the flat roll), and cannot measure the even-numbered rolling. The width affects the calculation accuracy of the width model.

At present, only the width after even-numbered rolling can be predicted, and there is a certain deviation in the result, which is not conducive to the precise control of the width. The present invention mainly utilizes on-site measuring instruments to calculate the width after even-numbered passes of rolling through a suitable vertical roll opening degree change curve in a mathematical manner, thereby improving the accuracy of width prediction.

Contents of the invention

Aiming at the problems existing in the prior art, the invention provides a method for controlling the width of a rolled piece in the rough rolling process of continuous hot rolling.

Technical scheme of the present invention is:

A method for controlling the width of a rolled piece in a hot continuous rolling rough rolling process, comprising the following steps:

Step 1: Obtain hot continuous rolling PDI data, including the data of the original billet, the thickness and width of the intermediate billet, and the thickness and width of the finished product;

Step 2: Determine the total number of rolling passes according to the technical requirements of the rolling plan;

Step 3: Determine the exit thickness, exit width and threading speed of each pass according to the thickness and width of the intermediate billet;

Step 3.1: Determine the outlet thickness of each pass;

Step 3.2: Determine the exit width of each pass;

Step 3.3: Obtain the threading speed of each pass according to the thickness of the intermediate billet and the set thickness of each pass;

Step 4: The rough rolling process starts, and a rolling schedule is calculated and sent to the rolling line equipment; the rolling schedule includes: the opening of the vertical roll and the roll gap of the flat roll;

Step 4.1: The rolled piece enters the vertical roll and the flat roll in turn, and the hot continuous rolling rough rolling process starts;

Step 4.2: Measure the odd-numbered width after the first pass by the width gauge at the exit of the rough rolling;

Step 4.3: According to the measured width of the odd-numbered first pass, correct the flat roll gap of the even-numbered first pass, and send it to the rolling line equipment for even-numbered first-pass rolling;

Step 5: Calculating the width of the even-numbered first pass after rolling;

Step 5.1: Calculating the thickness after rolling in the first odd-numbered pass and the thickness after rolling in the first even-numbered pass;

Step 5.2: During the rolling process of the first even-numbered pass, the opening of the vertical rolls gradually decreases according to the unit step;

Step 5.3: When the rolling force signal appears, keep the rolling force of the vertical roll within a certain range by adjusting the opening of the vertical roll;

Step 5.4: After the rolling force has stabilized for a period of time, take the average value of the opening of the vertical rolls within this period of time, that is, the width after rolling of the current even-numbered first pass;

Step 6: Calculate the openness of the vertical rolls of the odd second pass and send it to the rolling line equipment;

Step 6.1: According to the rolling width of the first odd-numbered pass and the rolled width of the first even-numbered pass, calculate the amount of free spread and the coefficient of free spread during the rolling process of the first even-numbered pass;

Step 6.2: According to the odd-numbered width after the first pass, calculate the dog-bone width and the dog-bone spread coefficient;

Step 6.3: According to the free splay coefficient and the dog-bone splay coefficient, calculate the vertical roll opening degree and the flat roll roll gap of the odd-numbered second pass;

Step 7: Repeat steps 4 to 6 to continuously adjust the opening of the vertical roll and the roll gap of the flat roll according to the width of the odd-numbered passes and the rolled thickness of the even-numbered passes to complete the width control of the hot continuous rolling rough rolling , until the end of the hot continuous rolling rough rolling process, an intermediate billet that meets the width requirements in the PDI data is obtained.

Beneficial effect:

The invention can accurately measure the rolled width of the even-numbered passes in the rough rolling process, and solves the problem that the rolled width of the even-numbered passes cannot be measured without a width measuring instrument. The invention has high safety and accurate calculation, and can obtain the width after even-pass rolling by online calculation, and can be successfully applied in the width control process of hot continuous rolling and rough rolling, replacing the role of the width measuring instrument, and saving production investment costs at the same time , which improves the precision of width control.

Description of drawings

Fig. 1 is a schematic diagram of instrument configuration of a typical hot continuous rolling roughing unit "vertical roll+flat roll" according to a specific embodiment of the present invention;

Fig. 2 is the schematic diagram of the width change after the first pass of the specific embodiment of the present invention, (a) is the cross-sectional shape of the raw material slab, (b) is the cross-sectional shape after vertical roll rolling, (c) is the cross-sectional shape after passing through the flat Cross-sectional shape after rolling;

Fig. 3 is the rolling force variation curve that changes with vertical roller opening degree according to the specific embodiment of the present invention;

Fig. 4 is a flow chart of a method for controlling the width of a rolled piece in the hot continuous rolling rough rolling process according to a specific embodiment of the present invention.

detailed description

The specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings.

This implementation mode adopts a typical hot continuous rolling roughing unit, and adopts the arrangement of "vertical roll + flat roll" as shown in Figure 1. The measuring instruments include: ① hot metal detectors before, during and after the machine ② before and after the machine Temperature measuring instrument behind the machine ③ Width measuring instrument behind the machine ④ Vertical roller displacement sensor, pressure sensor, speed encoder ⑤ Flat roller displacement sensor, pressure sensor, speed encoder.

The functions of each measuring instrument are: the hot metal detector is used to track the specific position of the rolled piece during the rolling process; the thermometer is used to measure the temperature of the rolled piece; the width gauge is used to measure the The width of the piece; the displacement sensor is used to measure the position of the vertical roll (flat roll); the pressure sensor is used to measure the rolling force during the rolling process; the speed encoder is used to measure the rotational speed of the vertical roll (flat roll) during the rolling process.

The rolling direction is from left to right (defined as odd-numbered passes), and from right to left (defined as even-numbered passes). As shown in Figure 2, during the rolling production process, the intermediate billet (outline in Figure 2(a)) passes through odd-numbered passes first through vertical roll rolling (outline in Figure 2(b)), and then through flat rolls Rolling (contour in Fig. 2(c)); even-numbered passes, first pass through flat roll rolling, vertical roll does not participate in the control (fully open), reciprocating rolling, and finally complete the rolling process.

The rolling direction is from left to right (defined as odd-numbered passes), and from right to left (defined as even-numbered passes). In the production process, the odd-numbered passes first pass through the vertical roll rolling, and then pass through the flat roll rolling; the even-numbered passes first pass through the flat roll rolling, the vertical roll does not participate in the control (fully open), reciprocating rolling, and finally completes the rolling process. making process.

A method for controlling the width of a rolled piece in a hot continuous rolling rough rolling process, as shown in Figure 4, comprises the following steps:

Step 1: Obtain hot continuous rolling PDI (Primary Date Input) data, including the data of the original billet, the thickness and width of the intermediate billet, and the thickness and width of the finished product;

Hot continuous rolling starts production of new rolling stock. First, it goes through the rough rolling stage. The rough rolling process control system receives the PDI production data from the host computer (production control level), mainly including the data of the original billet, such as steel coil number, steel type , furnace number, billet length, width, thickness, intermediate billet thickness, width, temperature, and finished product thickness, width, etc. The billet will be rolled through the rough rolling unit with a total of odd passes.

Step 2: Determine the total number of rolling passes according to the technical requirements of the rolling plan;

Step 3: Determine the exit thickness, exit width and rough rolling strip threading speed of each pass according to the thickness and width of the intermediate billet;

Step 3.1: Determine the outlet thickness of each pass;

According to the distribution mode of the reduction rate, the outlet thickness of each pass is determined, and the calculation formula is as follows:

h _i =H _i ·(1-r _i ), wherein, h _i is the outlet thickness of the i-th pass, H _i is the inlet thickness of the _i -th pass, and ri is the thickness reduction rate of the i-th pass;

Step 3.2: Determine the exit width of each pass;

According to the distribution mode of the reduction rate, the outlet width of each pass is determined, and the calculation formula is as follows:

w _i =W _i ·(1-r _wi ), wherein, w _i is the exit width of the i-th pass, W _i is the entrance width of the i-th pass, and r _wi is the width reduction rate of the i-th pass;

Step 3.3: According to the thickness of the intermediate billet and the thickness set for each pass, look up the table to obtain the threading speed of each pass;

Step 4: The rough rolling process starts, and a rolling schedule is calculated and sent to the rolling line equipment; the rolling schedule includes: the opening of the vertical roll and the roll gap of the flat roll;

Step 4.1: The rolled piece enters the vertical roll and the flat roll in turn, and the hot continuous rolling rough rolling process starts;

Figure 2(a) is the cross-sectional shape of the raw material slab, where L1 is the thickness h ₀ of the slab; L2 is the width w ₀ of the slab; Figure 2(b) is the cross-sectional shape after vertical roll rolling, where L3 L4 is the maximum height of the dog bone h _d ; L5 is the width w _E of the vertical roll after rolling; L6 is the position of the dog bone peak _{L p} ; L7 is the length of the dog bone affected area L _d ; L8 is dogbone widening Figure 2(c) is the cross-sectional shape after flat roll rolling, where L9 is the thickness h ₁ after rolling with odd passes; L10 is the natural widening L11 is the rolling width w ₁ of odd passes.

Step 4.2: Measure the odd-numbered width after the first pass by the width gauge at the exit of the rough rolling;

Width after rolling in the odd i-th pass:

w _i ＝w _E,i +Δw _D,i +Δw _N,i (1) In the formula: i is the pass number; w _E,i is the width before flat roll rolling of the odd i pass; Δw _D,i is the width of the dog bone; Δw _N,i is the free width;

The dog bone width Δw _D,i is calculated by formula (2):

Δw _D,i ＝s _E (w _i -w _E,i ) (2) where: s _E is the dog bone widening coefficient;

Free width Δw _N,i is calculated by formula (3):

In the formula: S _B is the free expansion coefficient; h _i-1 is the inlet thickness of the odd i-th pass; h _i is the outlet thickness of the odd i-th pass;

Step 4.3: According to the width w _i measured by the width gauge at the exit of rough rolling, correct the flat roll gap of the first even pass, and send it to the rolling line equipment for the first even pass rolling;

Step 5: Calculating the width of the even-numbered first pass after rolling;

During the even-numbered rolling process, the vertical rolls do not participate in the width control, and the flat rolls participate in the reduction control. The calculation formula for the rolled width of the even-numbered passes is:

w _i =w _i-1 +Δw _N,i (4)

In the formula: w _i-1 is the width value after rolling in the last odd pass, and Δw _N,i is the amount of free width.

Step 5.1: Calculating the thickness after rolling in the first odd-numbered pass and the thickness after rolling in the first even-numbered pass;

When the odd-numbered first pass is rolled, the width after rolling is w ₁ ; the thickness after rolling is h ₁ , and h ₁ is calculated by the bouncing equation:

In the formula: S ₁ is the roll gap value of the odd-numbered first flat roll rolling, which is detected by the flat roll displacement sensor; F ₁ is the measured value of the odd-numbered first flat roll rolling force, which is detected by the flat roll pressure sensor Get; K _m is the rolling mill stiffness;

The post-rolling thickness h2 after the even _- numbered first pass rolling can be calculated by the bouncing equation:

In the formula: S ₂ is the roll gap value of the flat roll rolling in the first even-numbered pass; F ₂ is the measured value of the flat-roll rolling force in the first even-numbered pass;

Step 5.2: During the rolling process of the first even-numbered pass, the opening of the vertical rolls gradually decreases according to the unit step;

During the rolling process of the first even-numbered pass, when the hot metal detector at the entrance of the rough rolling (the exit of the even-numbered pass, instrument ① in Fig. 1) detects that the rolled piece reaches this position, a corresponding tracking signal will be generated. At this time, the opening degree of the vertical roll gradually decreases from large to small according to the unit step length of 0.02mm/ms, and approaches the rolled piece in the rolling process until the pressure sensor of the vertical roll shows a reading. At this time, the opening degree change curve of the vertical roll and the corresponding rolling force change curve are shown in Figure 3:

Step 5.3: When the rolling force signal appears, keep the rolling force of the vertical roll within a certain range by adjusting the opening of the vertical roll;

Step 5.4: After the rolling force has stabilized for a period of time, take the average value of the opening of the vertical rolls within this period of time, that is, the width after rolling of the current even-numbered first pass;

When the vertical roll is in contact with the rolled piece (point A in Figure 3), the pressure sensor of the vertical roll will receive the measurement signal F _E , in order to eliminate the interference of the noise signal of the rolling force, the vertical The opening of the roll shrinks or opens slowly to ensure that the rolling force fluctuates within the range of 0 to δF _E (δF _E = 60kN) (the impact on the width of the rolled piece within this range of rolling force can be ignored), and after a period of stability , the average value w of the opening of the vertical rolls during this sampling period (as shown by B in Fig. 3), the average value is the actual width w ₂ of the rolled piece in this pass, that is, the rolled width of the current even-numbered first pass .

Step 6: Calculate the openness of the vertical rolls of the odd second pass and send it to the rolling line equipment;

Step 6.1: According to the rolling width of the first odd-numbered pass and the rolled width of the first even-numbered pass, calculate the amount of free splay and the coefficient of free splay during the rolling process of the first even-numbered pass;

Use the width w ₁ before rolling in the first even-numbered pass (that is, the width after rolling in the first odd-numbered pass) and the actual width w ₂ after rolling in the first even-numbered pass (calculated ), calculate the free width Δw _N,2 in the rolling process of the first even-numbered pass, and obtain from the formula (3): Δw _N,2 =w ₂ -w ₁ ;

Since even passes only have natural width, Δw _D,2 = 0, the thickness h ₁ and h ₂ before and after rolling can be calculated according to formula (5) and formula (6), and the free width can be obtained from formula (3) Expansion coefficient:

Step 6.2: According to the odd-numbered width w ₁ of the first rolling pass, calculate the dog-bone spread and the dog-bone spread coefficient;

According to formula (1) and formula (3), the calculated free spread coefficient S _B can be obtained as the equation system shown in formula (8), and the free spread Δw _N of odd-numbered first-pass rolling can be obtained by solving _,1 :

Solving the equation, we get

Substituting formula (9) into formula (2), the dog bone expansion coefficient S _E can be calculated:

Step 6.3: According to the free splay coefficient and the dog-bone splay coefficient, calculate the vertical roll opening degree of the odd second pass;

According to the obtained actual width w ₂ of the even-numbered first pass, according to the formula (1), (2), (3) and formula (7) (10) to adjust the re-opening of the vertical roll of the odd-numbered first pass Continue to set, obtain w _E,i that satisfies the conditions, and obtain the odd-numbered second pass exit width required by the setting.

In the formula: Targets require width for odd second passes.

Step 7: Repeat steps 4 to 6, continuously adjust the opening of the vertical rolls according to the width of the odd-numbered passes and the rolled thickness of the even-numbered passes, and complete the width control of the rolled piece during the hot continuous rolling rough rolling process until the hot rolling The continuous rolling rough rolling process ends, and the intermediate billet meeting the width requirements in the PDI data is obtained.

After each pass is calculated, the calculated value is sent to HMI (HumanMachineInterface) and basic automation Level1 for execution, and the corresponding rolling process is carried out. A typical rolling schedule is shown in Table 1.

Table 1 Calculation results of typical rolling schedule

Claims (1)

1. a rougher of hot strip mill process rolled piece width control method, is characterized in that: comprise the following steps:

Step 1: obtain hot continuous rolling PDI data, comprise the data of original blank, the thickness of intermediate blank and width, and the thickness of finished product and width;

Step 2: according to rolling scaduled technological requirement, determines total road number of times of rolling;

Step 3: determine the exit thickness of each passage, exit width and threading speed according to the thickness of intermediate blank and width;

Step 3.1: determine each passage exit thickness;

Step 3.2: determine each passage exit width;

Step 3.3: according to workpiece thickness and each passage setting thickness, obtain the threading speed of each passage;

Step 4: rolling process of rough rolling starts, carries out a rolling schedule calculation and is issued to rolling line equipment; Rolling procedure comprises: edger roll opening degree peace roller gap;

Step 4.1: rolled piece enters edger roll and plain-barreled roll successively, the rougher of hot strip mill operation of rolling starts;

Step 4.2: the width gage exported by roughing is measured odd number first passage and rolled rear width;

Step 4.3: odd number first passage according to measuring rolls rear width, revises the plain-barreled roll roll gap of even number first passage, and is issued to rolling line equipment and carries out even number first passes;

Step 5: calculate even number first passage and roll rear width;

Step 5.1: calculate odd number first passage outgoing gauge and current even number first passage outgoing gauge;

Step 5.2: in the even number first passage operation of rolling, edger roll opening degree reduces gradually according to one step;

Step 5.3: when there is roll-force signal, makes edge rolling try hard to keep by adjustment edger roll opening degree and holds within limits;

Step 5.4: roll-force after a period of stabilisation, gets edger roll opening degree mean value in this time period, namely current even number first passage roll rear width;

Step 6: calculate the edger roll opening degree of odd number second passage and be issued to rolling line equipment;

Step 6.1: that rolls rear width and even number first passage according to odd number first passage rolls rear width, calculates the unrestricted spread amount in the even number first passage operation of rolling and unrestricted spread coefficient;

Step 6.2: roll rear width according to odd number first passage, calculates dog bone absolute spread and dog bone spread coefficient;

Step 6.3: the edger roll opening degree peace roller gap calculating odd number second passage according to unrestricted spread coefficient and dog bone spread coefficient;

Step 7: repeat step 4 ~ step 6, the outgoing gauge of rear width and each passage of even number is rolled according to each passage of odd number, continuous opposite roller opening degree peace roller gap adjusts, complete rougher of hot strip mill rolled piece width control system, until the rougher of hot strip mill operation of rolling terminates, obtain the intermediate blank meeting width requirement in PDI data.