CN106984651A - An On-Line Control System for Improving the Precision of Rolling Thickness Control - Google Patents

Abstract

The invention provides an online control system for improving the control precision of the thickness of a rolled piece, which utilizes a temperature measuring device of the rolled piece at the inlet side of a rolling stand and a thickness measuring device of the rolled piece at the outlet side of a rolling mill to perform compensation calculation on a roll gap in real time, and specifically comprises the following steps: calculating the influence coefficient of the plastic processing temperature of the rolled piece relative to the thickness change of the rolled piece according to the measured data of the rolled piece temperature measuring and thickness measuring device; thereby calculating and obtaining the increase and decrease value of the thickness of the rolled piece at the outlet side of the rolling mill, which is generated by the temperature change of the rolled piece; meanwhile, the influence of the processing temperature on the physical properties of the rolled piece is compensated by using the corrected value of the physical properties of the material; and performing real-time compensation control on the roll gap of the roll according to the roll gap deviation calculation result. The invention can eliminate the problem of poor thickness control precision caused by uneven plastic processing temperature of the rolled piece, and the thickness control precision of different thickness specifications is improved by more than 2 percent.

Description

An On-Line Control System for Improving the Precision of Rolling Thickness Control

technical field

The invention belongs to the field of metal plastic processing control, and in particular relates to an on-line control system for improving the thickness control precision of rolled pieces.

Background technique

The thickness index of the rolled piece is one of the most important quality indicators for the control of the rolled piece, and the factors affecting the thickness control mainly include the following aspects: slab temperature change, strip tension change, speed influence, roll gap change, etc. In the production of hot-rolled strip steel, automatic thickness control (AGC) is one of the main means to improve the accuracy of thickness control. Therefore, a complete automatic thickness control system needs to fully consider the influence of various factors on thickness control, and have corresponding The compensation function is eliminated.

At present, the thickness automatic control system is mainly divided into two control modes: GM-AGC and MN-AGC. Among them, GM-AGC mode considers factors such as roll state, rolling speed, and tension between stands, while MN-AGC corrects GM-AGC through the measured strip thickness.

In the above method for controlling the thickness of the rolled piece, the predicted thickness H of the rolled piece at the exit side of the rolling mill is:

H=F/M+S _r

Among them: H represents the predicted thickness of the rolled piece at the exit side of the rolling mill, F represents the rolling force exerted by the rolling mill on the rolled piece, M represents the stiffness of the rolling mill, and S _r represents the compensation for the roll gap position of the rolling mill. Among them, the compensation value S _r for the roll gap position of the rolling mill:

S _r ＝S ₀ +S _WRS +S _RW +S _RH

Among them: S _r includes the following types of rack roll gap compensation: S ₀ represents the zero mark of the rack roll gap; S _OIL is the compensation value for the rack roll oil film change during the rotation acceleration process of the rack roll; S _WRS is the roll shifting compensation value of the rack roll produced by the lateral movement of the rack roll; S _WRB is the compensation value of the rack roll bending force generated by the rack roll under the load bending force; S _RW is the rolling force of the rolled piece In the process, the wear compensation value of the rolled piece on the surface of the stand roll; S _RH is the thermal expansion compensation value of the stand roll generated by the temperature change of the stand roll during the rolling process. Therefore, the above method for controlling the thickness of the rolled piece does not take any consideration of the change of the hardness of the rolled piece caused by the change of the plastic processing temperature of the rolled piece, that is, the change of the physical properties of the rolled piece.

Patent CN103934278A discloses a method of using computer program to control the thickness of hot-rolled finish-rolled strip steel. According to the detection value of the rolling performance value data of the stand, the strip thickness at the exit of the stand is calculated; the calculated strip thickness data of the stand is tracked At the moment of reaching the frame, combined with the actual rolling performance data of the frame, the plastic coefficient of the strip passing through the frame is calculated in real time; according to the plastic coefficient of the strip calculated in real time, the adjustment amount of the roll gap of the frame is determined, and the thickness of the strip is determined. Perform real-time feed-forward control. Although this patent can obtain the strip plasticity coefficient of different sections of a rolled strip, that is, the change of the strip plasticity coefficient caused by the hardness change of the rolled piece has been taken into account, but in this technical solution, the adjustment amount of F _x stand roll gap is Calculated based on the thickness control deviation and the plasticity coefficient of the strip steel, without considering the thickness of the roll oil film, roll shifting, roll bending force, roll surface wear, and the influence of roll thermal expansion on the roll gap during rolling, only a fixed compensation value is used Make corrections. Therefore, the method of this patent still can cause the thickness control accuracy of the steel strip on the exit side of the rolling mill to be relatively poor. At the same time, this control method can only be applied to two or more continuous rolling stands, and is not suitable for the thickness control of a single-stand rolling mill.

Contents of the invention

The object of the present invention is to provide an on-line control system for improving the thickness control accuracy of rolled pieces, by using the rolling piece temperature measuring device at the entrance side of the rolling mill stand and the rolled piece thickness measuring device at the rolling mill exit side, the roll gap is compensated and calculated in real time, Eliminate the poor thickness control accuracy of the rolled piece caused by the uneven plastic processing temperature of the rolled piece.

In order to solve the problems of the technologies described above, the present invention has the following technical solutions:

An on-line control system for improving the thickness control accuracy of a rolled piece includes: at least one rolling mill 4, a rolling piece temperature measuring device 2 at the entrance side of the rolling mill 5, a rolling piece thickness measuring device 3 at the rolling mill exit side 6, and an automatic control device for the rolling piece thickness 7. The rolling piece thickness automatic control device 7 includes: the influence coefficient calculation unit S100 for calculating the temperature change rate of plastic processing and the influence coefficient of thickness fluctuation, the temperature and thickness compensation calculation unit S200 for calculating the temperature deviation of plastic processing and the compensation value of thickness fluctuation; Material physical property correction unit S300 for property parameter compensation value; Roll gap deviation calculation unit S400 for calculating roll gap deviation.

Further, in S100 of the online control system for improving the precision of rolling stock thickness control, the difference between the detected value of the rolling stock thickness and the target thickness measured by the rolling stock thickness measuring device 3 at the rolling mill exit side 6 and the deviation value of the rolling stock thickness at the rolling mill entry side 5 The rolling piece temperature measuring device 2 measures the rate of change of the rolling piece plastic processing temperature as a variable, and establishes a relationship function between the plastic processing temperature deviation and the rolling piece target thickness deviation.

Further, in S200 of the on-line control system for improving the thickness control accuracy of rolled pieces, the calculation results in S100 are used to calculate and predict the thickness deviation δH _t+Δt value of 6 rolled pieces at the outlet side of the rolling mill stand and to eliminate the thickness deviation of the rolled pieces Required mill stand thickness compensation deviation value δh't _+Δt :

δH _t+Δt =Inf_coe×δT _t+Δt +δH _t ;

Among them: δH _t is the deviation between the thickness of the rolled piece detected by the rolling piece thickness measuring device 3 at the exit side 6 of the lower rolling mill at time _t and the target control thickness; The deviation between the thickness of the rolled _piece detected by the rolling piece thickness measuring device 3 and the target control thickness; Processing temperature change rate; M is the stiffness coefficient of the rolling mill; Q is the plasticity coefficient of the rolling material.

Further, in S300 of the on-line control system for improving the precision of rolling piece thickness control, different material physical property parameter correction values are used to calculate the deviation value δh _t+Δt of rolling piece thickness control on the outlet side 6 of the final rolling mill:

δh _t+Δt = δh' _t+Δt ×α;

Among them, δh _t+Δt is the deviation value of the thickness control of the rolled piece 6 on the exit side of the rolling mill at the time t+Δt (Δt>0); α is the correction value of the physical property parameters of the material.

Further, in S400 of the on-line control system for improving the control accuracy of rolled piece thickness, the roll gap deviation compensation value δS _t+Δt is calculated:

Among them, δS _t+Δt is the roll gap deviation compensation value at t+Δt (Δt>0).

Compared with the prior art, the present invention has at least the following beneficial effects:

1. The present invention uses the rolling piece temperature measuring device at the entrance side of the rolling mill stand and the rolling piece thickness measuring device at the rolling mill exit side to establish the influence coefficient of the plastic processing temperature change of the rolled piece and the thickness change of the rolled piece to correct the roll gap of the stand , which can eliminate the deviation between the thickness of the rolled piece at the exit side of the rolling mill and the target control thickness caused by the uneven plastic processing temperature of the rolled piece, and improve the overall thickness control accuracy of the rolled piece;

2. The present invention can be applied not only to continuous rolling mills, but also to the thickness control of rolled pieces in single-stand rolling mills, and is a direct and effective thickness control method with a wide range of adaptability;

3. The present invention can be implemented by programming the basic automation controller, and can be realized without replacing or transforming the original equipment or controller, which is an economical and reliable method.

Description of drawings

Fig. 1 shows equipment device and control flow chart of the present invention,

Among them, 1-rolling piece, 2-rolling piece temperature measuring device, 3-rolling piece thickness measuring device, 4-rolling mill, 5-rolling mill entrance side, 6-rolling mill exit side, 7-rolling piece thickness automatic control device;

Fig. 2 is the strip thickness control deviation curve of Strip1;

Fig. 3 is the strip thickness control deviation curve of Strip2 coil.

detailed description

In order to better understand the above technical solutions of the present invention, a further detailed description will be given below in conjunction with the drawings and embodiments.

Fig. 1 is the equipment device and control flow chart of the present invention, it can be seen that the online control system for improving the thickness control accuracy of the rolled piece in the present invention includes: a rolled piece 1, at least one rolling mill 4, a rolled piece temperature measuring device 2 on the entrance side of the rolling mill 5, The rolled piece thickness measuring device 3 and the rolled piece thickness automatic control device 7 on the rolling mill exit side 6; the rolled piece thickness automatic control device 7 includes: calculating the influence coefficient calculation unit S100 for calculating the temperature change rate of plastic processing and the influence coefficient of thickness fluctuation, and calculating the plastic processing Temperature and thickness compensation calculation unit S200 for temperature deviation and thickness fluctuation compensation value; material physical property correction unit S300 for calculating material physical property parameter compensation value; roll gap deviation calculation unit S400 for calculating roll gap deviation.

In the influence coefficient calculation unit S100, the difference between the detected value of the rolled piece thickness measured by the rolled piece thickness measuring device 3 on the exit side of the rolling mill and the target thickness is compared with the plastic processing temperature of the rolled piece measured by the rolling piece temperature measuring device 2 on the rolling mill entrance side 5 The rate of change is used as a variable to establish a relationship function between the plastic processing temperature deviation and the target thickness deviation of the rolled piece.

In the temperature thickness compensation calculation unit S200, use the calculation results in S100 to calculate and predict the value of the thickness deviation δH _t+Δt of the 6 rolled pieces at the exit side of the rolling mill stand and the thickness compensation deviation value δh of the rolling mill stand required to eliminate the thickness deviation of the rolled piece ' _t+Δt :

δH _t+Δt =Inf_coe×δT _t+Δt +δH _t ;

Among them: δH _t is the deviation between the thickness of the rolled piece detected by the rolling piece thickness measuring device 3 at the exit side 6 of the lower rolling mill at time _t and the target control thickness; The deviation between the thickness of the rolled _piece detected by the rolling piece thickness measuring device 3 and the target control thickness; Processing temperature change rate; M is the stiffness coefficient of the rolling mill; Q is the plasticity coefficient of the rolling material.

In the material physical property correction unit S300, different material physical property parameter correction values are used to calculate the deviation value δh _t+Δt of the rolled piece thickness control on the exit side 6 of the final rolling mill:

δh _t+Δt = δh' _t+Δt ×α;

Among them, δh _t+Δt is the deviation value of the thickness control of the rolled piece 6 on the exit side of the rolling mill at the time t+Δt (Δt>0); α is the correction value of the physical property parameters of the material.

In the roll gap deviation calculation unit S400, the roll gap deviation compensation value δS _t+Δt is calculated:

Among them, δS _t+Δt is the roll gap deviation compensation value at t+Δt (Δt>0).

The following are specific steps for eliminating the influence of different plastic processing temperatures of rolled pieces on thickness control accuracy by adopting the online control system of the present invention to improve the thickness control accuracy of rolled pieces:

The starting end of the rolled piece 1 passes through the rolling mill 4 and the rolled piece thickness measuring device 3 on the exit side 6 of the stand, 5 seconds after detecting the actual effective data of the rolled piece, starts the automatic control device 7 for the thickness of the rolled piece; When the temperature measuring device 2 of the rolled piece detects that the plastic processing temperature data at the end of the rolled piece 1 is invalid, the self-control device 7 for the thickness of the rolled piece is stopped.

In S100, the variation δH _t of the deviation between the thickness of the rolled piece detected by the 6 rolling piece thickness measuring devices 3 on the exit side of the rolling mill and the target control thickness at the current moment (time t) is compared with the 5 rolling piece temperature measuring devices on the rolling mill stand entrance side in the same period 2 The plasticity temperature variation δT _t of the rolled piece obtained constitutes a first-order differential function. Through the above derivation, the calculation result of the function can be used as the value Inf_coe of the plasticity temperature influence function of the rolled piece.

In S200, according to the calculation result of S100, the time t+Δt (Δt=200ms) is predicted, the thickness deviation δH _t+Δt of the rolled piece 6 at the exit side of the rolling mill stand:

δH _t+Δt =Inf_coe×δT _t+Δt +δH _t ,

Among them, δH _t is the deviation between the thickness of the rolled piece detected by the thickness measuring device 3 at the exit side of the lower rolling mill and the target control thickness at time t, and δH _{t + Δt} is t + Δt (Δt = 200ms) at the time t + Δt (Δt = 200ms) The deviation between the thickness of the rolled _piece detected by the piece thickness measuring device and the target control thickness; .

The rolling mill stand thickness compensation deviation δh' _t+Δt at the moment t+Δt (Δt=200ms) is obtained from the thickness deviation δH _t+Δt of the rolled piece:

Among them, δh't _+Δt is the thickness compensation deviation of the rolling mill stand corresponding to the thickness deviation of the rolled piece; M is the stiffness coefficient of the rolling mill, and Q is the plasticity coefficient of the rolled piece material.

There are differences in the rate of change of plastic processing temperature and the amount of change in deformation resistance of rolled pieces (1) with different composition systems.

S300 subdivides the rolled piece 1 of different composition systems, and divides the rolled piece 1 of similar composition system into the same steel race, and different steel races use different material physical property parameter correction values to calculate the final rolling mill at the next moment The thickness control difference δh _t+Δt of the 6 rolling pieces at the exit side:

δh _t+Δt = δh' _t+Δt ×α,

Among them, δh _t+Δt is the deviation value of the thickness control of the rolled piece 6 on the exit side of the rolling mill at the time t+Δt (Δt>0); α is the correction value of the physical property parameters of the material.

S400 determines the compensation value δS _t+Δt for the roll gap deviation of the rolling mill according to the calculated thickness control deviation δh _t+Δt of the rolled piece:

The on-line control system for improving the thickness control accuracy of the rolled piece of the present invention is implemented in the last stand F6 of the continuous rolling group of the 1700mm hot rolling production line. The steel thickness detection devices together constitute the measured data and carry out on-line control of the strip thickness. After the invention is implemented, the strip thickness control precision of the 1700mm hot rolling production line is obviously improved.

As an analysis and comparison, the thickness control methods of the present invention and the present invention are respectively carried out, and the actual thickness curves of two coils of the same steel type and specification are compared. Among them, the steel types shown in the comparison are the same as J40BNNB2, and the plastic processing temperature trends of the analyzed and compared steel strips are similar, and the target finished product thickness is the same as 3.75mm.

The strip thickness control curves that are not rolled by the present invention are shown in Figure 2, as can be seen from Figure 2, the strip thickness control deviation is closely related to the plastic processing temperature of the strip, and there is a negative correlation between the overall fluctuations of the two Trend: Strip 1 coil strip thickness peaks at the low point of plastic processing temperature, with a tolerance of 100um, and the overall thickness control accuracy is 96.1% (control deviation 50um). Adopt the steel strip thickness control curve that the present invention is rolled as shown in Figure 3, can see from Figure 3: Strip2 roll is similar with Strip1 coil plastic working temperature fluctuation, all there is plastic working temperature low point, but Strip2 The thickness control deviation peak corresponding to the low plastic processing temperature of the roll has been eliminated, the thickness control deviation curve of this roll has been significantly improved, and the overall thickness control accuracy reaches 98.5% (control deviation 50um). Table 1 shows the statistical data of the thickness control accuracy of the steel type J40BNNB2 before and after the present invention is put into use.

Table 1 Implementation effect of the present invention

It can be seen from Table 1 that after the present invention is put into use, the thickness control accuracy of different thickness specifications can be increased by more than 2%.

Although the present invention discloses some embodiments, it is not intended to limit the present invention. The present invention can also have other multiple implementation modes, and those skilled in the art can make various corresponding changes according to the present invention, but these corresponding changes should belong to the protection scope of the appended claims of the present invention.

Claims (5)

1. a kind of on-line control system for improving rolled piece thickness control accuracy, it is characterised in that the on-line control system includes：Extremely Few 1 rolling mill (4), the rolled piece temperature measuring equipment (2) of inlet of rolling mill side (5), milling train outlet side (6) rolled piece measuring thickness device (3) with And rolled piece device for automatically control thickness (7)；Rolled piece device for automatically control thickness (7) includes：Computational plasticity processing temperature rate of change The influence coefficient calculation unit S100 of coefficient, computational plasticity processing temperature deviation and thickness fluctuation offset are influenceed with thickness fluctuation Temperature thickness compensation computing unit S200；Calculate the material physical properties amending unit of material physical properties parameter offset S300；The roller gap deviation for calculating roller gap deviation calculates cell S 400.

2. the on-line control system according to claim 1 for improving rolled piece thickness control accuracy, it is characterised in that described In S100, the rolled piece Thickness sensitivity value and the deviation of target thickness that the rolled piece measuring thickness device (3) of milling train outlet side (6) is measured Variable, the plasticity of foundation are used as with rolled piece temperature measuring equipment (2) the measurement rolled piece plastic working rate of temperature change of inlet of rolling mill side (5) The relation function of processing temperature deviation and rolled piece target thickness deviation.

3. the on-line control system according to claim 1 for improving rolled piece thickness control accuracy, it is characterised in that described In S200, using result of calculation in S100, prediction rolling-mill housing outlet side (6) rolled piece thickness deviation δ H are calculated_t+ΔtValue and to disappear Except the rolling-mill housing thickness compensation deviation δ h' required for this rolled piece thickness deviation_t+Δt：

δH_t+Δt=Inf_coe × δ T_t+Δt+δH_t；

${\mathrm{\δh}}_{t+\mathrm{\Δ}t}^{\′}=\left(\frac{M}{Q+M}\right)\×{\mathrm{\δH}}_{t+\mathrm{\Δ}t};$

Wherein：δH_tIt is thick for the rolled piece thickness of rolled piece measuring thickness device (3) detection of milling train outlet side (6) and target control under t The deviation of degree；δH_t+ΔtFor t+ Δs t (Δ t>0) rolled piece that rolled piece measuring thickness device (3) detection of milling train outlet side (6) is inscribed when is thick The deviation of degree and target control thickness；δT_t+ΔtFor t+ Δs t (Δ t>0) the rolled piece temperature measuring equipment of inlet of rolling mill side (5) is inscribed when (2) the rolled piece plastic working rate of temperature change of detection；M is mill modulus；Q is rolled piece material plasticity coefficient.

4. the on-line control system according to claim 1 for improving rolled piece thickness control accuracy, it is characterised in that described In S300, using different material physical properties parameter correction values, the rolled piece thickness control of final milling train outlet side (6) is calculated Deviation δ h_t+Δt：

δh_t+Δt=δ h'_t+Δt×α；

Wherein δ h_t+ΔtFor t+ Δs t (Δ t>0) deviation of moment milling train outlet side (6) rolled piece thickness control；α is Material Physics Nature parameters correction value.

5. the on-line control system according to claim 1 for improving rolled piece thickness control accuracy, it is characterised in that described In S400, roller gap bias compensation value δ S are calculated_t+Δt：

${\mathrm{\δS}}_{t+\mathrm{\Δ}t}=\frac{M+Q}{Q}\×{\mathrm{\δh}}_{t+\mathrm{\Δ}t};$

Wherein δ S_t+ΔtFor t+ Δs t (Δ t>0) moment roller gap bias compensation value.