CN1840255A - Extension coefficient and plate shape integrated control method in steel strip flattening process - Google Patents

Abstract

The invention discloses a belt steel flattening elongation and slab-shaped complex control method, which is characterized by the following: the invention can choose draught pressure mode by comparing draught pressure adjusting elongation algebraic system and tension adjusting elongation algebraic system or use tension mode to control elongation, which can control rolling process of planisher according to set point of every processing parameter and relevant on-line measured value; the tension is controlled in draught pressure control mode, when the draught pressure accumulation regulating variable is over finite limit and the draught pressure keeps constant; the draught pressure is adjusted in tension control mode, when the tension accumulation regulating variable is over finite limit and the tension keeps constant; the curve roll force is adjusted when adjusting draught pressure.

Description

Belt steel flating percentage elongation and plate shape integrated control method

Technical field

The present invention relates to a kind of production method of steel, particularly a kind of belt steel flating percentage elongation and board-shape control method.

Background technology

Cold rolling levelling is to being rolled with less plastic deformation (percentage elongation is generally 0.2%～3%) through the band steel after the recrystallization annealing, with elimination yield point elongation, control panel shape, and the operation of rolling of the surface topography that obtains requiring.No matter be traditional or modern cold-rolling process process, smooth one of the production link that all is absolutely necessary.Because smooth is the belt plate shape of decision finished product, last procedure of mechanical performance, so the percentage elongation of planisher and the control of plate shape have very important significance for the quality that improves cold-strip steel.

Connect the planisher that moves back in the unit for a most galvanizing unit and a part at present, do not have the closed-loop control of plate shape, mainly adopt permanent elongation control (being the percentage elongation closed-loop control) and permanent draught pressure control (being the draught pressure closed-loop control) dual mode.When adopting the percentage elongation closed-loop control, when the percentage elongation actual value departs from setting value, adjust draught pressure or tension force, make actual percentage elongation get back to desired value.According to rolling therory as can be known, the adjustment of draught pressure can cause the variation of load roll gap.Because in existing each control system, generally do not have bending roller force to follow the function that draught pressure is regulated automatically, the percentage elongation closed-loop control will inevitably bring harmful effect to exit plate shape.When adopting the draught pressure closed-loop control, the draught pressure fluctuation is little, helps improving plate shape, but because percentage elongation is actually open loop control, its control accuracy is difficult to guarantee.

In the permanent elongation control mode of present planisher, adopting many is the draught pressure mode, promptly when the percentage elongation actual value with setting value deviation takes place, by adjusting draught pressure elimination deviation.Also have some systems to adopt draught pressure mode and tensionless mode simultaneously, promptly select the draught pressure mode, select tensionless mode for other specification band steel for the band steel of some specification.The system of selection that dual mode is general is: the band steel for thinner thickness is selected tensionless mode, selects the draught pressure mode for the band steel that thickness is thicker, is perhaps determined by artificial selection.

The problem that existing permanent elongation control mode exists mainly comprises:

1, only adopts the system of draught pressure mode, for thin thickness, band steel that strength grade is high, because percentage elongation is insensitive to draught pressure, when the percentage elongation deviation ratio is big, although the draught pressure regulated quantity is very big, the percentage elongation deviation may not necessarily be eliminated fully, thereby influences the elongation control precision.

2, adopt at the same time in the system of draught pressure mode and tensionless mode, the system of selection of control mode is too simple, has only considered the belt steel thickness factor, can not reflect the sensitivity of percentage elongation to draught pressure and tension force comprehensively.Such as for the high band steel of strength grade, even it is thicker, it is much smaller that its percentage elongation also may be compared tension force to the draught pressure sensitivity, this moment is if select the draught pressure mode to control percentage elongation, cause the draught pressure regulated quantity bigger than normal easily, smooth exit plate shape and system stable operation are caused adverse effect.

Even the control mode of 3 percentage elongation is selected rationally, only singlely by regulating draught pressure or tensionless mode control percentage elongation, (it is bigger to preset error as draught pressure, tension force) in some cases, draught pressure or tension buildup regulated quantity situation bigger than normal still might occur, can bring harmful effect to exit plate shape and system stable operation equally.

Summary of the invention

Purpose of the present invention provides a kind of belt steel flating percentage elongation and plate shape integrated control method, is guaranteeing under the prerequisite of system stability, improves the percentage elongation and the plate shape control accuracy of band in the cold-strip steel smoothing and rolling process.

To achieve these goals, the present invention has adopted following technical scheme:

A kind of belt steel flating percentage elongation and plate shape integrated control method are by process computer and basic automatization programmable controller PLCThe control planisher is implemented, and comprises following key element:

A, to being about to smooth coiled strip steel, to the thickness h of process computer input tape steel and setting value, the setting value of tension force T, the setting value of bending roller force S, the setting value of percentage elongation ε, the percentage elongation deviation ε of width b, draught pressure P ₀Set-point and online calculate draught pressure to percentage elongation carry-over factor k by process computer _{P ε}, tension force is to percentage elongation carry-over factor k _{σ ε}, bending roller force is to draught pressure carry-over factor k _Sp, draught pressure regulates percentage elongation cost coefficient k _PcWith tension adjustment percentage elongation cost coefficient k _Tc

B, by process computer relatively draught pressure regulate percentage elongation cost coefficient k _PcWith tension adjustment percentage elongation cost coefficient k _TcSize and its default definite value as this winding steel sent to basic automatization PLC, when draught pressure is regulated the percentage elongation cost coefficient less than tension adjustment percentage elongation cost coefficient, select the draught pressure mode to control percentage elongation; When draught pressure is regulated the percentage elongation cost coefficient greater than tension adjustment percentage elongation cost coefficient, select tensionless mode control percentage elongation;

C, basic automatization PLC carry out skin pass rolling according to each setting value and each on-line measurement value control planisher of process computer to the band steel; In the draught pressure control mode, when draught pressure accumulation regulated quantity surpasses certain limit, keep draught pressure constant, again tension force is regulated; In the tension force control mode, when the tension buildup regulated quantity surpasses certain limit, keep tension force constant, again draught pressure is regulated;

D, when draught pressure is regulated, bending roller force is followed the draught pressure adjusted in concert;

E, when the absolute value of the deviation of percentage elongation measured value and set-point during less than the given deviate of percentage elongation, draught pressure or tension force are not regulated.

Belt steel flating percentage elongation of the present invention and board-shape control method make it compared with prior art owing to adopted above technical scheme, also have following advantage and characteristics:

1, defines draught pressure adjusting cost coefficient and tension adjustment cost coefficient owing to taken all factors into consideration factors such as belt steel thickness, resistance of deformation and capacity of equipment, and according to the control mode of its relative size choose reasonable percentage elongation, can accurately reflect the sensitivity of percentage elongation, improve the percentage elongation and the plate shape control accuracy of band in the cold-strip steel smoothing and rolling process greatly draught pressure, tension force.

2, comprehensively brought into play draught pressure, tension force regulating action, can avoid occurring draught pressure or the excessive situation of tension adjustment amount percentage elongation.

3,, eliminate the harmful effect of draught pressure adjustment to belt plate shape because when draught pressure was regulated, bending roller force was followed the draught pressure adjusted in concert, can keep smooth exit plate shape constant substantially.

4, because when in the control accuracy scope that the deviation of percentage elongation actual value and set-point is requiring, draught pressure or tension force are not regulated, can realize coordination control, can avoid the frequent adjusting of draught pressure, tension force simultaneously, improve the stability of a system percentage elongation and plate shape.

Description of drawings

Fig. 1 is that the elongation control mode among the present invention is selected logic chart.

Fig. 2 is that the draught pressure mode among the present invention is controlled block diagram.

Fig. 3 is the tensionless mode control block diagram among the present invention.

The specific embodiment

Belt steel flating percentage elongation of the present invention and plate shape integrated control method further describe as follows:

Referring to Fig. 1, the present invention before smooth a certain band steel, compares draught pressure by process computer and regulates percentage elongation cost coefficient k in the operation of rolling _PcWith tension adjustment percentage elongation cost coefficient k _TcSize, work as k _PcLess than k _TcThe time, select the draught pressure mode to control percentage elongation; Work as k _PcGreater than k _TcThe time, select tensionless mode control percentage elongation.Process computer sends to elongation control mode selection result the programmable controller PLC of basic automatization level.Described draught pressure is regulated the percentage elongation cost coefficient and is meant that draught pressure can provide the ratio of maximum tension to percentage elongation carry-over factor and planisher tension system.Described tension adjustment percentage elongation cost coefficient is meant that tension force can provide the ratio of maximum tension to percentage elongation carry-over factor and planisher tension system.

If the control mode that PLC receives is the draught pressure mode, then the control principle of smooth percentage elongation can be described as follows in conjunction with Fig. 2:

Under the draught pressure mode, adopt percentage elongation and two closed loops of roll-force, the roll-force closed loop is as ring in the control, and the percentage elongation closed loop is as the control outer shroud.Calculate the mean value Δ ε of interior percentage elongation setting value of a regulating cycle and percentage elongation value of feedback (being measured value) deviate.In the percentage elongation deviation passage of percentage elongation closed loop, the dead band is set, when the percentage elongation deviation | Δ ε |＜ε ₀The time, the percentage elongation closed loop is not devoted oneself to work, and keeps permanent draught pressure control; When | Δ ε | 〉=ε ₀The time, the percentage elongation closed loop is devoted oneself to work, promptly at the setting value Psv of draught pressure closed loop with compensation rate Δ P (the Δ P=k that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ P in the past _{P ε}Δ ε), simultaneously at the setting value Ssv of bending roller force closed loop with compensation rate Δ S (the Δ S=k that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ S in the past _SpΔ P), make bending roller force follow roll-force variation and adjusting automatically.Above-mentioned adjustment process is up to | Δ ε |＜ε ₀Till.When certain regulating cycle occurs | Δ ε | 〉=ε ₀The time, if the roll-force compensation rate of each regulating cycle accumulation absolute value | ∑ Δ P+ Δ P| will surpass given draught pressure accumulation upper limit P ₀(general value be (0.1～0.5) Psv) keeps in the draught pressure ring set-point constant, the setting value Tsv of tension closed loop and before compensation rate Δ T (the Δ T=k that superposes on the basis of each regulating cycle accumulated compensation amount ∑ Δ T _{σ ε}Δ ε bh), up to | Δ ε |＜ε ₀Till.

If the control mode that PLC receives is a tensionless mode, then the control of smooth percentage elongation can be described as follows in conjunction with Fig. 3:

Under tensionless mode, adopt two control of percentage elongation and tension force closed loop, tension closed loop is as ring in the control, and the percentage elongation closed loop is as the control outer shroud.Calculate the mean value Δ ε of interior percentage elongation setting value of a regulating cycle and percentage elongation value of feedback (being measured value) deviate.In the percentage elongation deviation passage of percentage elongation closed loop, the dead band is set, when the percentage elongation deviation | Δ ε |＜ε ₀The time, the percentage elongation closed loop is not devoted oneself to work, and keeps permanent tension force control; When | Δ ε | 〉=ε ₀The time, the percentage elongation closed loop is devoted oneself to work, promptly at the setting value Tsv of tension closed loop with compensation rate Δ T (the Δ T=k that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ T in the past _{σ ε}Δ ε bh).Above-mentioned adjustment process is up to | Δ ε |＜ε ₀Till.When certain regulating cycle occurs | Δ ε | 〉=ε ₀The time, if the tension compensating amount of each regulating cycle accumulation absolute value | ∑ Δ T+ Δ T| will surpass given upper limit T ₀(general value be (0.1～0.3) Tsv) keeps in the tension force ring set-point constant, the setting value Psv of draught pressure closed loop and before compensation rate Δ P (the Δ P=k that superposes on the basis of each regulating cycle accumulated compensation amount ∑ Δ P _{P ε}Δ ε), simultaneously at the setting value Ssv of bending roller force closed loop with compensation rate Δ S (the Δ S=k that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ S in the past _SpΔ P), make bending roller force follow roll-force variation and adjusting automatically, up to | Δ ε |＜ε ₀Till.

ε in the above-mentioned dual mode ₀Span, generally the percentage elongation that requires allow departure 1/3 in.If the plate shape to some band steel is had relatively high expectations ε ₀Value suitably big, carry out accurate permanent draught pressure control, work as ε ₀Value when very big, the permanent draught pressure control of similar traditional sense.As the mechanical performance (percentage elongation) when having relatively high expectations to some band steel, ε ₀Value suitably smaller, carry out accurate permanent elongation control, work as ε ₀Value when very little, the permanent elongation control of similar traditional sense.

Adopt above control method, by comprehensive performance tension force and draught pressure control action to percentage elongation, the given deviate of choose reasonable percentage elongation, can realize coordination optimization control, overcome planisher and only carry out permanent elongation control or only carry out the drawback that permanent draught pressure control brings percentage elongation and plate shape.

Draught pressure among the present invention is to percentage elongation carry-over factor k _{P ε}Computing formula derive as follows:

According to rolling therory as can be known, draught pressure is front and back tensile stress σ ₀With σ ₁, band steel inlet thickness h ₀, strip width b, roller radius R _w, resistance of deformation k, percentage elongation ε, deformed area coefficientoffriction etc. function, promptly

P＝P(σ ₀，σ ₁，k，h ₀，ε，R _w，μ，b) (1)

By formula (1) as can be known, under the condition that other each related factors all remains unchanged, there are functional relation one to one in draught pressure and percentage elongation, i.e. P=P (ε).We are defined as draught pressure to percentage elongation carry-over factor k with draught pressure to the derivative of percentage elongation _{P ε}:

$k_{\mathrm{p\ϵ}}=\frac{\∂P}{\∂\mathrm{\ϵ}}\·\·\·\left(2\right)$

During Practical Calculation, can press following formula according to the draught pressure computation model and simplify calculating:

$k_{\mathrm{p\ϵ}}=\frac{\mathrm{\ΔP}}{\mathrm{\Δ\ϵ}}=\frac{P(\mathrm{\ϵ}+\mathrm{\Δ\ϵ})-P\left(\mathrm{\ϵ}\right)}{\mathrm{\Δ\ϵ}}$ (2’)

Tensile stress among the present invention is derived as follows to the computing formula of percentage elongation carry-over factor k σ ε:

At h ₀, b, R _w, under the constant prerequisite such as k, μ, differential is carried out on formula (1) both sides:

$\mathrm{\ΔP}=\frac{\∂P}{\∂{\mathrm{\σ}}_1}{\mathrm{\Δ\σ}}_1+\frac{\∂P}{\∂{\mathrm{\σ}}_0}{\mathrm{\Δ\σ}}_0+\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\Δ\ϵ}\·\·\·\left(3\right)$

When adopting adjustment of tonicity to regulate the percentage elongation deviation, keep draught pressure constant, i.e. Δ P=0 is obtained by formula (3):

$\frac{\∂P}{\∂{\mathrm{\σ}}_1}{\mathrm{\Δ\σ}}_1+\frac{\∂P}{\∂{\mathrm{\σ}}_0}\mathrm{\Δ}{\mathrm{\σ}}_0=-\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\Δ\ϵ}$

∴ $\mathrm{\Δ}{\mathrm{\σ}}_1=-\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\Δ\ϵ}/[\frac{\∂P}{\∂{\mathrm{\σ}}_1}+\frac{\∂P}{\∂{\mathrm{\σ}}_0}\left(\frac{\∂{\mathrm{\σ}}_0}{{\∂\mathrm{\σ}}_1}\right)]\·\·\·\left(4\right)$

In that forward and backward tension force is all identical when regulating, i.e. Δ σ ₀=Δ σ ₁, then

$\mathrm{\Δ}{\mathrm{\σ}}_1=\mathrm{\Δ}{\mathrm{\σ}}_0=-\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\Δ\ϵ}/(\frac{\∂P}{\∂{\mathrm{\σ}}_1}+\frac{\∂P}{\∂{\mathrm{\σ}}_0})$ (4’)

Thereby obtain the carry-over factor of tension force to percentage elongation:

$k_{\mathrm{\σ\ϵ}}=\frac{\mathrm{\Δ}{\mathrm{\σ}}_1}{\mathrm{\Δ\ϵ}}=\frac{{\mathrm{\Δ\σ}}_0}{\mathrm{\Δ\ϵ}}=-\frac{\∂P}{\∂\mathrm{\ϵ}}/(\frac{\∂P}{\∂{\mathrm{\σ}}_1}+\frac{\∂P}{{\∂\mathrm{\σ}}_0})\·\·\·\left(5\right)$

During Practical Calculation, can simplify to calculate by following formula according to the draught pressure computation model and (get Δ σ ₀=Δ σ ₁):

ΔP＝P(σ ₀+Δσ ₀，σ ₁+Δσ ₁，k，h ₀，ε，R _w，μ，b)-P(σ ₀，σ ₁，k，h ₀，ε，R _w，μ，b)

$k_{\mathrm{\σ\ϵ}}=-k_{\mathrm{p\ϵ}}/(\frac{\mathrm{\ΔP}}{{\mathrm{\Δ\σ}}_1}+\frac{\mathrm{\ΔP}}{{\mathrm{\Δ\σ}}_0})\·\·\·\left(6\right)$

Bending roller force among the present invention is to the carry-over factor k of roll-force _SpComputing formula derive as follows:

In order to compensate the influence of draught pressure P variation, need online compensation bending roller force setting value to exit plate shape.According to rolling therory as can be known, under all certain condition of other correlative factor, best bending roller force and draught pressure exist functional relation one to one, i.e. S _a=S (P).The best bending roller force variable quantity that definition unit draught pressure causes is that bending roller force is to draught pressure carry-over factor k _Sp, promptly

$k_{\mathrm{sp}}=\frac{\mathrm{\ΔS}}{\mathrm{\ΔP}}=\frac{S(P+\mathrm{\ΔP})-S\left(P\right)}{P(\mathrm{\ϵ}+\mathrm{\Δ\ϵ})-P\left(\mathrm{\ϵ}\right)}\·\·\·\left(7\right)$

According to formula (7), increment Delta ε of given percentage elongation ε utilizes total draught pressure P and best bending roller force S during Practical Calculation _aComputation model calculates corresponding Δ P and Δ S and gets final product.

Draught pressure among the present invention is regulated percentage elongation cost coefficient k _PcWith tension adjustment percentage elongation cost coefficient k _TcComputing formula derive as follows:

With draught pressure to percentage elongation carry-over factor k _{P ε}The maximum draught pressure P that can provide with the planisher press down system _MaxRatio be defined as draught pressure and regulate percentage elongation cost coefficient k _Pc, promptly

$k_{\mathrm{pc}}=\mathrm{\α}\frac{k_{\mathrm{p\ϵ}}}{P_{\max }}\·\·\·\left(8\right)$

α in the formula (α＞0) is a proportionality coefficient (usually getting α=1 gets final product).

With tension force to percentage elongation carry-over factor k _{σ ε}The maximum tension T that can provide with the planisher tension system _MaxRatio be defined as tension adjustment percentage elongation cost coefficient k _Tc, promptly

$k_{\mathrm{tc}}=\mathrm{\β}\frac{k_{\mathrm{\σ\ϵ}}\mathrm{hb}}{T_{\max }}\·\·\·\left(9\right)$

β in the formula (β＞0) is a proportionality coefficient (usually getting β=1 gets final product), and h, b are respectively the thickness and the width of band steel.

Below further specify as follows by two specific embodiments to belt steel flating percentage elongation of the present invention and plate shape integrated control method:

Embodiment 1

Steel grade trade mark DC51, thickness h=1.2mm, width b=1000mm, percentage elongation set-point ε _Sv=0.8%, percentage elongation allows control deviation ± 0.2%, the maximum tension T that the planisher tension system can provide _Max=90KN, the maximum draught pressure P that the planisher press down system can provide _Max=4000KN, the setting value Tsv=61KN of tension force before and after getting, percentage elongation deviation ε ₀=0.2% ÷ 3=0.067%.

With correlation models such as the draught pressure model of above-mentioned parameter difference input process computer, best bending roller force models, by calculating draught pressure setting value Psv=1710KN, bending roller force sets value Ssv=101KN, and draught pressure is to percentage elongation carry-over factor k _{P ε}=61502KN, tension force is to percentage elongation carry-over factor k _{σ ε}=12.8KN/mm ², bending roller force is to draught pressure carry-over factor k _Sp=0.07.According to formula (8) (getting α=1.0), obtain draught pressure and regulate percentage elongation cost coefficient k _Pc=15.4, obtain tension adjustment percentage elongation cost coefficient k according to formula (9) (getting β=1.0) _Tc=170.7.Get the limit P of draught pressure accumulation regulated quantity ₀=0.2Psv=0.2 * 1710=342KN, the limit T of tension buildup regulated quantity ₀=0.3Tsv=0.3 * 61=18.3KN.

Select logic chart according to elongation control mode shown in Figure 1, because k here _Pc＜k _Tc, select the draught pressure mode to control percentage elongation.

Draught pressure mode according to Fig. 2 is controlled block diagram, and the control procedure in a certain control cycle is as follows:

If a certain elongation control in the cycle percentage elongation measured value be 0.83%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.83%=-0.03% because |-0.03%|＜ε ₀(=0.067%) so ring is not done the set-point adjustment in the draught pressure, keeps draught pressure constant, and so far this control cycle finishes, and enters next control cycle.

If a certain elongation control in the cycle percentage elongation measured value be 0.71%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.71%=0.09% because this deviation | 0.09%| is greater than percentage elongation deviation set-point ε ₀(=0.067%) need be adjusted respectively the set-point of ring or tension force control loop in the draught pressure, wherein Δ P=k _{P ε}Δ ε=61502 * 0.09%=55.4KN, Δ S=k _SpΔ P=0.07 * 55.4KN=3.9KN.If each control cycle draught pressure accumulation regulated quantity is ∑ Δ P=102KN before this, bending roller force accumulation regulated quantity is ∑ Δ S=10.3KN.Each regulated quantity accumulation absolute value that comprises current control cycle is | ∑ Δ P+ Δ P|=102+55.4=157.4KN, owing to surpass draught pressure accumulation regulated quantity upper limit P ₀(=342KN), ring is controlled by new set-point Psv+ ∑ Δ P+ Δ P=1710+102+55.4=1867.4KN in the so current control cycle draught pressure, the bending roller force control loop is controlled by new set-point Ssv+ ∑ Δ S+ Δ S=101+10.3+3.9=115.2KN, so far this control cycle finishes, and enters next control cycle.

If a certain elongation control in the cycle percentage elongation measured value be 0.71%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.71%=0.09% because this deviation | 0.09%| is greater than percentage elongation deviation set-point ε ₀(=0.067%) need be adjusted the set-point of ring or tension force control loop in the draught pressure, wherein Δ P=k _{P ε}Δ ε=61502 * 0.09%=55.4KN, Δ S=k _SpΔ P=0.07 * 55.4KN=3.9KN.If each control cycle draught pressure accumulation regulated quantity is ∑ Δ P=302KN before this, bending roller force accumulation regulated quantity is ∑ Δ S=10.3KN.Each regulated quantity accumulation absolute value that comprises current control cycle is | ∑ Δ P+ Δ P|=302+55.4=357.4KN, owing to surpassed draught pressure accumulation regulated quantity upper limit P ₀(=342KN), the set-point of ring remains unchanged in the so current control cycle draught pressure, still control by Psv+ ∑ Δ P=1710+357.4=2067.4KN, bending roller force control loop set-point remains unchanged thereupon, need adjust the set-point of tension link.Δ T=k _{σ ε}Δ ε bh=12.8 * 0.09% * 1.2 * 1000=13.8KN, if each control cycle tension buildup regulated quantity is ∑ Δ T=0 before this, ring is controlled by new set-point Tsv+ ∑ Δ T+ Δ T=61+0+13.8=74.8KN in the so current control cycle tension force, so far this control cycle finishes, and enters next control cycle.

Embodiment 2

Steel grade trade mark DC51, thickness h=0.2mm, width b=1000mm, percentage elongation set-point ε _Sv=0.8%, percentage elongation allows control deviation ± 0.2%, the maximum tension T that the planisher tension system can provide _Max=90KN, the maximum draught pressure P that the planisher press down system can provide _Max=4000KN, the setting value Tsv=21KN of tension force before and after getting, percentage elongation deviation ε ₀=0.2% ÷ 3=0.067%.

With correlation models such as the draught pressure model of above-mentioned parameter difference input process computer, best bending roller force models, by calculating draught pressure setting value Psv=2827KN, bending roller force sets value Ssv=196KN, and draught pressure is to percentage elongation carry-over factor k _{P ε}=87833KN, tension force is to percentage elongation carry-over factor k _{σ ε}=4.4KN/mm ², bending roller force is to draught pressure carry-over factor k _Sp=0.12.According to formula (8) (getting α=1.0), obtain draught pressure and regulate percentage elongation cost coefficient k _Pc=22.0, obtain tension adjustment percentage elongation cost coefficient k according to formula (9) (getting β=1.0) _Tc=9.8.Get the limit P of draught pressure accumulation regulated quantity ₀=0.2Psv=0.2 * 2827=565KN, the limit T of tension buildup regulated quantity ₀=0.3Tsv=0.3 * 21=6.3KN.

Select logic chart according to elongation control mode shown in Figure 1, because k here _Pc＞k _Tc, select tensionless mode control percentage elongation.

According to the tensionless mode control block diagram of Fig. 3, the control procedure in a certain control cycle is as follows:

If a certain elongation control in the cycle percentage elongation measured value be 0.84%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.84%=-0.04% because |-0.04%|＜ε ₀(=0.067%) so ring is not done the set-point adjustment in the tension force, keeps constant tension, and so far this control cycle finishes, and enters next control cycle.

If a certain elongation control in the cycle percentage elongation measured value be 0.7%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.7%=0.1% because this deviation | 0.1%| is greater than percentage elongation deviation set-point ε ₀(=0.067%) need adjust Δ T=k to the set-point of ring or draught pressure control loop in the tension force _{σ ε}Δ ε bh=4.4 * 0.1% * 0.2 * 1000=0.88KN.If each control cycle tension buildup regulated quantity is ∑ Δ T=2.1KN before this, each regulated quantity accumulation absolute value that comprises current control cycle is | ∑ Δ T+ Δ T|=2.1+0.88=2.98KN, owing to do not surpass the limit T of tension buildup regulated quantity ₀Ring is controlled by new set-point Tsv+ ∑ Δ T=21+2.98=23.98KN in the (=6.3KN), so current control cycle tension force, and so far this control cycle finishes, and enters next control cycle.

If a certain elongation control in the cycle percentage elongation measured value be 0.7%, percentage elongation setting value and deviation of measuring value Δ ε=0.8%-0.7%=0.1% because this deviation | 0.1%| is greater than percentage elongation deviation set-point ε ₀(=0.067%) need adjust Δ T=k to the set-point of ring or draught pressure control loop in the tension force _{σ ε}Δ ε bh=4.4 * 0.1% * 0.2 * 1000=0.88KN.If each control cycle tension buildup regulated quantity is before this | ∑ Δ T|=6.1KN, each regulated quantity accumulation absolute value that comprises current control cycle be | ∑ Δ T+ Δ T|=6.1+0.88=6.98KN, owing to surpassed the limit T of tension buildup regulated quantity ₀The set-point of ring remains unchanged in the (=6.3KN), so current control cycle tension force, still controls by Tsv+ ∑ Δ T=21+6.1=27.1KN, need adjust draught pressure control loop and bending roller force control loop set-point.ΔP＝k _pεΔε＝87833×0.1％＝87.8KN、ΔS＝k _spΔP＝0.12×87.8KN＝10.5KN。If each control cycle draught pressure accumulation regulated quantity is ∑ Δ P=0 before this, bending roller force accumulation regulated quantity is ∑ Δ S=0, ring is controlled by new set-point Psv+ ∑ Δ P+ Δ P=2827+0+87.8=2914.8KN in the so current control cycle draught pressure, the bending roller force control loop is controlled by new set-point Ssv+ ∑ Δ S+ Δ S=196+0+10.5=206.5KN, so far this control cycle finishes, and enters next control cycle.

Claims (7)

1, a kind of belt steel flating percentage elongation and plate shape integrated control method are implemented by process computer and basic automatization programmable controller PLC control planisher, it is characterized in that, comprise following key element:

A, to being about to smooth coiled strip steel, to the thickness h of process computer input tape steel and setting value, the setting value of tension force T, the setting value of bending roller force S, the setting value of percentage elongation ε, the percentage elongation deviation ε of width b, draught pressure P ₀Set-point and online calculate draught pressure to percentage elongation carry-over factor k by process computer _{P ε}, tension force is to percentage elongation carry-over factor k _{σ ε}, bending roller force is to draught pressure carry-over factor k _Sp, draught pressure regulates percentage elongation cost coefficient k _PcWith tension adjustment percentage elongation cost coefficient k _Tc

B, by process computer relatively draught pressure regulate percentage elongation cost coefficient k _PcWith tension adjustment percentage elongation cost coefficient k _TcSize and its default definite value as this winding steel sent to basic automatization PLC, when draught pressure is regulated the percentage elongation cost coefficient less than tension adjustment percentage elongation cost coefficient, select the draught pressure mode to control percentage elongation; When draught pressure is regulated the percentage elongation cost coefficient greater than tension adjustment percentage elongation cost coefficient, select tensionless mode control percentage elongation;

C, basic automatization PLC carry out skin pass rolling according to each setting value and each on-line measurement value control planisher of process computer to the band steel; In the draught pressure control mode, when draught pressure accumulation regulated quantity surpasses certain limit, keep draught pressure constant, again tension force is regulated; In the tension force control mode, when the tension buildup regulated quantity surpasses certain limit, keep tension force constant, again draught pressure is regulated;

D, when draught pressure is regulated, bending roller force is followed the draught pressure adjusted in concert;

E, when the absolute value of the deviation of percentage elongation measured value and set-point during less than the given deviate of percentage elongation, draught pressure or tension force are not regulated.

2, belt steel flating percentage elongation according to claim 1 and board-shape control method, it is characterized in that: in the described draught pressure mode, adopt percentage elongation and two closed loops of roll-force, the roll-force closed loop is as ring in the control, the percentage elongation closed loop is as the control outer shroud, calculate the mean value Δ ε of interior percentage elongation setting value of a regulating cycle and percentage elongation measured value deviate, in the percentage elongation deviation passage of percentage elongation closed loop, the dead band is set, when

The time, the percentage elongation closed loop is not devoted oneself to work, and keeps permanent draught pressure control; When | Δ ε | 〉=ε ₀The time, the percentage elongation closed loop is devoted oneself to work, at the setting value Psv of draught pressure closed loop with the compensation rate Δ P that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ P in the past, simultaneously at the setting value Ssv of bending roller force closed loop with the compensation rate Δ S that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ S in the past, make bending roller force follow roll-force variation and adjusting automatically, up to

Till; When certain regulating cycle occurs | Δ ε | 〉=ε ₀The time, if the roll-force compensation rate of each regulating cycle accumulation absolute value | ∑ Δ P+ Δ P| will surpass given upper limit P ₀, keep in the draught pressure ring set-point constant, at the setting value Tsv of tension closed loop with the compensation rate Δ T that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ T in the past, up to Till.

3, belt steel flating percentage elongation according to claim 1 and board-shape control method, it is characterized in that: in the described tensionless mode, adopt two control of percentage elongation and tension force closed loop, tension closed loop is as ring in the control, the percentage elongation closed loop is as the control outer shroud, calculate the mean value Δ ε of interior percentage elongation setting value of a regulating cycle and percentage elongation measured value deviate, in the percentage elongation deviation passage of percentage elongation closed loop, the dead band is set, when

The time, the percentage elongation closed loop is not devoted oneself to work, and keeps permanent tension force control; When | Δ ε | 〉=ε ₀The time, the percentage elongation closed loop is devoted oneself to work, at the setting value Tsv of tension closed loop with the compensation rate Δ T that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ T in the past, up to

Till; When certain regulating cycle occurs | Δ ε | 〉=ε ₀The time, if the tension compensating amount of each regulating cycle accumulation absolute value | ∑ Δ T+ Δ T| will surpass given upper limit T ₀It is constant to keep encircling set-point in the tension force, at the setting value Psv of draught pressure closed loop with the compensation rate Δ P that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ P in the past, simultaneously at the setting value Ssv of bending roller force closed loop with the compensation rate Δ S that superposeed on the basis of each regulating cycle accumulated compensation amount ∑ Δ S in the past, make bending roller force follow roll-force variation and adjusting automatically, up to Till.

4, belt steel flating percentage elongation according to claim 1 and board-shape control method is characterized in that: the limit P of described draught pressure accumulation regulated quantity ₀Span be the draught pressure closed loop setting value Psv 0.1-0.5 doubly, described tension buildup regulated quantity T ₀The limit span be tension closed loop setting value Tsv 0.1-0.3 doubly.

5, belt steel flating percentage elongation according to claim 1 and board-shape control method is characterized in that: described percentage elongation deviation ε ₀The value of set-point less than 1/3rd of percentage elongation allowable error.

6, according to claim 2 or 3 described belt steel flating percentage elongation and board-shape control methods, it is characterized in that: described tension force stack compensation rate Δ T=k _{σ ε}Δ ε bh; Described draught pressure stack compensation rate Δ P=k _{P ε}Δ ε; Described bending roller force stack compensation rate Δ S=k _SpΔ P.

7, belt steel flating percentage elongation according to claim 1 and board-shape control method is characterized in that: described draught pressure is regulated percentage elongation cost coefficient k _PcCalculate by following formula:

$k_{\mathrm{pc}}=\mathrm{\α}\frac{k_{\mathrm{p\ϵ}}}{P_{\max }}$

In the formula, α is a proportionality coefficient, generally gets α=1; P _MaxThe maximum draught pressure that can provide for the planisher pressure system;

Described tension adjustment percentage elongation cost coefficient k _TcCalculate by following formula:

$k_{\mathrm{tc}}=\mathrm{\β}\frac{k_{\mathrm{\σ\ϵ}}\mathrm{hb}}{T_{\max }}$

In the formula, β is a proportionality coefficient, generally gets β=1; H is the thickness of band steel; B is the width of band steel; T _MaxThe maximum tension that can provide for the planisher tension system;

Described draught pressure is to percentage elongation carry-over factor k _{P ε}Calculate by following formula:

$k_{\mathrm{p\ϵ}}=\frac{\mathrm{\ΔP}}{\mathrm{\Δ\ϵ}}=\frac{P(\mathrm{\ϵ}+\mathrm{\Δ\ϵ})-P\left(\mathrm{\ϵ}\right)}{\mathrm{\Δ\ϵ}}$

In the formula, Δ ε is the measured value of percentage elongation and the deviation of setting value;

Described tension force is to percentage elongation carry-over factor k _{σ ε}Calculate by following formula:

$k_{\mathrm{\σ\ϵ}}=-k_{\mathrm{p\ϵ}}/(\frac{\mathrm{\ΔP}}{{\mathrm{\Δ\σ}}_1}+\frac{\mathrm{\ΔP}}{{\mathrm{\Δ\σ}}_0})$

In the formula, σ ₀Be forward pull, σ ₁Be backward pull;

Described bending roller force is to draught pressure carry-over factor k _SpCalculate by following formula:

$k_{\mathrm{sp}}=\frac{\mathrm{\ΔS}}{\mathrm{\ΔP}}=\frac{S(P+\mathrm{\ΔP})-S\left(P\right)}{P(\mathrm{\ϵ}+\mathrm{\Δ\ϵ})-P\left(\mathrm{\ϵ}\right)}.$

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