CN101683660A - Control method of tandem cold rolling mill emulsion section cooling - Google Patents

Abstract

The invention discloses a control method of tandem cold rolling mill emulsion section cooling, comprising the following steps: a. collecting the device parameter of a rolling mill and the key parameter of band steel to be rolled; b. collecting a technological lubrication institution parameter; c. giving emulsion section cooling flow distribution initial value and iteration precision; d. calculating corresponding work roll thermal crown; e. calculating the lateral distribution value of a slipping factor; f. comparing the slipping factor maximum value with a critical value; g. calculating the lateral distribution value of a slip injury index; h. comparing the maximum value of the slip injury index with the critical value; i. calculating the corresponding strip shape distribution value; j. calculating the function value of a strip shape objective function; and k. judging whether Powell condition is available, and obtaining the control curve of the optimal section cooling flow. The controlmethod of the invention combines device section condition with practical flow control precision to set the emulsion flow in sections, reduces problems of slipping, hot slip injury and the like causedby lubrication and ensures the strip shape and the surface quality index of chassis outlet strip steel rolled stock.

Description

Control method of tandem cold rolling mill emulsion section cooling

Technical field

The present invention relates to a kind of cold continuous rolling production Technology, particularly a kind of control method of tandem cold rolling mill emulsion section cooling.

Background technology

Fig. 1 is the schematic diagram of cold belt steel continuous rolling process, and as shown in Figure 1, band 1 is delivered to frame after uncoiler 2 rolls out, and passes through the rolling of a plurality of frames, and band 1 reaches the thickness of regulation and is sent to coiling machine 3 backrush.The roll of each frame comprises backing roll 4 and working roll 5, and wherein working roll 5 directly contacts with band 1 surface.In the cold continuous rolling production process, because fricative distortion heat and frictional heat between metal deformation and metal and the roll, the roll roll surface temperature is raise gradually, form certain roll crown, produce certain hot-rolling type and production board shape is affected, so must effectively cool off by breaker roll.Like this, as shown in Figures 2 and 3, row's nozzle 6 is set near working roll 5, sprays emulsion to working roll 5 and band 1 surface, realize the cooling of roll and band by nozzle 6.

Practice shows, can be by to the reasonable control of emulsion section cooling control system and the band that correctly is used to obtain excellent surface quality and plate shape in cold continuous rolling process.But most of tandem mills does not have corresponding segmentation control model for segmentation emulsion spray beam in the frame in the prior art, rely on artificial experience to set the emulsion flow and adopt, though other has the fraction unit that certain emulsion section control model is arranged, but correlation model is mainly based on plate shape problem, relate to and the problem of preventing and treating with hot sliding injury of skidding rarely had, can not guarantee the production capacity performance of milling train and the surface quality of finished strip.

Summary of the invention

The object of the present invention is to provide a kind of control method of tandem cold rolling mill emulsion section cooling, this control method bonding apparatus segmentation situation and actual flow control accuracy are carried out the segmentation of emulsion flow and are set, reduce because problems such as skidding of causing of lubrication problem and heat scuffings guarantee that simultaneously frame exports the plate shape and the surface quality index of band.

The present invention is achieved in that

A kind of control method of tandem cold rolling mill emulsion section cooling may further comprise the steps:

(a) collect the device parameter of milling train and the key parameter of band steel to be rolled;

(b) the lubricated system parameter of collection process;

(c) given emulsion section cooling flow distribution initial value X ₀={ Q _0jJ=1,2 ..., N} and initial step length and termination precision;

(d) calculate corresponding work roll thermal crown Δ D _Wti

(e) calculate slip factor cross direction profiles value ψ _i

(f) judge inequality max (ψ _i)≤ψ ^*Whether set up, if set up then change step (g) over to; If be false, then repeating step (d) is to (e), till inequality is set up;

(g) calculate slip injury index cross direction profiles value

(h) judge inequality

Whether set up, wherein:

Be the critical slip injury index of milling train, if set up then change step (I) over to; If be false, then repeating step (d) is to (g), till inequality is set up;

(i) calculate corresponding plate shape distribution value σ _1i

(j) functional value of calculating plate shape objective function F (X);

(k) judge whether the Powell condition is set up,, repeat above-mentioned steps (d), set up, finish to calculate, draw optimal segmentation cooling flow-control curve until the Powell condition to step (j) if be false.

The present invention is evenly to be target with frame outlet band forward pull cross direction profiles (being plate shape), with the integrated control of skidding with hot sliding injury is constraints, guarantee the plate shape and the surface quality index of frame outlet band simultaneously, bonding apparatus segmentation situation and actual flow control accuracy are carried out the segmentation of emulsion flow and are set, and reduce because problems such as skidding of causing of lubrication problem, heat scuffings.Control method principle of the present invention is clear, and computational speed is fast, is suitable for online use.

Description of drawings

Fig. 1 is the schematic diagram of cold belt steel continuous rolling process;

Fig. 2 is an emulsion cooling schematic diagram in the cold belt steel continuous rolling process;

Fig. 3 is the arrangement of nozzles schematic diagram;

Fig. 4 is a control method of tandem cold rolling mill emulsion section cooling flow chart of the present invention;

Fig. 5 draws emulsion flow distribution curve map according to method of the present invention and conventional method among first embodiment;

Fig. 6 is the slip factor cross direction profiles figure that draws according to method of the present invention and conventional method among first embodiment;

Fig. 7 is the slip injury index cross direction profiles figure that draws according to method of the present invention and conventional method among first embodiment;

Fig. 8 is the band forward pull cross direction profiles figure that draws according to method of the present invention and conventional method among first embodiment;

Fig. 9 draws emulsion flow distribution curve map according to method of the present invention and conventional method among second embodiment;

Figure 10 is the slip factor cross direction profiles figure that draws according to method of the present invention and conventional method among second embodiment;

Figure 11 is the slip injury index cross direction profiles figure that draws according to method of the present invention and conventional method among second embodiment;

Figure 12 is the band forward pull cross direction profiles figure that draws according to method of the present invention and conventional method among second embodiment;

The specific embodiment

The invention will be further described below in conjunction with the drawings and specific embodiments.

Referring to Fig. 4, a kind of control method of tandem cold rolling mill emulsion section cooling may further comprise the steps:

(a) collect the device parameter of milling train and the key parameter of band steel to be rolled;

(b) the lubricated system parameter of collection process;

(c) given emulsion section cooling flow distribution initial value X ₀={ Q _0jJ=1,2 ..., N} and iteration precision ε;

(d) calculate corresponding work roll thermal crown Δ D _Wti

(e) calculate slip factor cross direction profiles value ψ _i

(f) judge inequality max (ψ _i)≤ψ ^*Whether set up, if set up then change step (g) over to; If be false, then repeating step (d) is to (e), till inequality is set up;

(g) calculate slip injury index cross direction profiles value

(h) judge inequality

Whether set up, wherein: Be the critical slip injury index of milling train, if set up then change step (I) over to; If be false, then repeating step (d) is to (g), till inequality is set up;

(i) calculate corresponding plate shape distribution value σ _1i

(j) functional value of calculating plate shape objective function F (X);

(k) judge whether the Powell condition is set up,, repeat above-mentioned steps (d), set up, finish to calculate, draw optimal segmentation cooling flow-control curve until the Powell condition to step (j) if be false.

The device parameter of milling train comprises described in the step (a): working roll barrel length L _W, work roll diameter D _W, backing roll barrel length L _b, backing roll diameter D _b, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂, maximum bending roller force S, maximum draught pressure P, maximum mill speed V, work original roller type Δ D _Wyi, backing roll original roller type Δ D _Bi, the critical slip factor ψ of milling train ^*, the critical slip injury index of milling train

The key parameter of band steel to be rolled comprises described in the step (a): strip width B, and band outlet average thickness h, band inlet average thickness H comes the length mean value L of flitch shape, comes the length cross direction profiles value L of flitch shape _i, the total tension force T of outlet side ₁, the total tension force T of entrance side ₀

Technological lubrication system parameter comprises described in the step (b): the temperature of emulsion, concentration.

Wherein step (a) and step (b) are the starting stages of control method.

The calculating of work roll thermal crown described in the step (d) is adopted with drag:

$\mathrm{\Δ}{D}_{\mathrm{wti}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(a_{\mathrm{ij}}\·Q_j),j=\mathrm{1,2},\·\·\·,N$

N-emulsion cooling hop count in the formula;

Q _jThe emulsion flow of-Di j section;

a _IjThe emulsion flow of-Di j section is to the influence coefficient of i section work roll thermal crown;

Δ D _Wti-work roll thermal crown.

Slip factor ψ described in the step (e) _iCalculating adopt with drag:

${\mathrm{\ψ}}_i=\frac{1}{4(a+b\·e^{-c\·\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(c_{\mathrm{ij}}\·\underset{k=1}{\overset{N}{\mathrm{\Σ}}}(b_{\mathrm{jk}}\·Q_k))})}|\sqrt{\frac{\mathrm{\Δ}{h}_i}{{R_i}^{\′}}}+\frac{T_{0i}-T_{1i}}{P_i}|$

In the formula: a-fluid friction coefficient, main relevant with the character of lubricating oil own;

B-dry friction influence coefficient, relevant with the contact condition of deformed area;

C-oil film thickness influence coefficient;

Δ h _i-Di i section passage absolute draft amount;

P _iThe total draught pressure of-Di i section;

R _i'-i section working roll flattens radius

c _IjThe working roll temperature field of-Di j section is to the influence coefficient of the oil film thickness of lubricating oil in the i section roll gap;

b _IjThe emulsion flow of-Di j section is to the influence coefficient in i section working roll temperature field.

Slip injury index cross direction profiles value described in the step (g)

Calculating adopt with drag:

In the formula: d _IjThe working roll temperature field of-Di j section is to i section strip steel temperature cross direction profiles influence coefficient;

e _IjThe belt steel surface temperature of-Di j section is to the influence coefficient of i section slip injury index.

The calculating of the functional value of plate shape objective function F (X) described in the step (j) is adopted with drag:

F(X)＝((max(σ _1i)-min(σ _1i))/T ₁)

In the formula: T ₁The total tension force of-outlet side.

Technical scheme to this case is elaborated below.

Can know according to relevant rolling therory and field experience, the temperature field of working roll and hot convexity and the heat flow rate taken away from roller surface unit are infinitesimal by emulsion in the unit interval are closely related in cold continuous rolling process, and heat flow rate depends on the roll and the cooling fluid coefficient of heat transfer.Meanwhile, under the certain prerequisite of the Pressure, Concentration, Temperature of emulsion, the coefficient of heat transfer then is the function of emulsion flow.Like this, can obtain by analyzing, under the prerequisite that other condition is determined, the hot convexity of working roll and temperature field are the functions of emulsion flow, can represent with following formula:

$\mathrm{\Δ}{D}_{\mathrm{wti}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(a_{\mathrm{ij}}\·Q_j),j=\mathrm{1,2},\·\·\·,N---\left(1\right)$

$T_{\mathrm{wi}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(b_{\mathrm{ij}}\·Q_j),j=\mathrm{1,2},\·\·\·,N---\left(2\right)$

N-emulsion cooling hop count in the formula;

Q _jThe emulsion flow of-Di j section;

a _IjThe emulsion flow of-Di j section is to the influence coefficient of i section work roll thermal crown;

b _IjThe emulsion flow of-Di j section is to the influence coefficient in i section working roll temperature field;

Δ D _Wti-work roll thermal crown;

T _Wi-working roll temperature field cross direction profiles.

Meanwhile, in cold continuous rolling process, when one timing of band emulsion flow cross direction profiles, the temperature field of working roll is to the oil film thickness cross direction profiles ξ of lubricating oil in the roll gap _iJust play decisive influence.In other words, can be with the oil film thickness cross direction profiles ξ of lubricating oil in the roll gap _iFunction with formula (3) is represented:

${\mathrm{\ξ}}_i=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(c_{\mathrm{ij}}\·T_{\mathrm{wj}})---\left(3\right)$

$T_{\mathrm{bi}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(d_{\mathrm{ij}}\·T_{\mathrm{wj}})---\left(4\right)$

In the formula:

c _IjThe working roll temperature field of-Di j section is to the influence coefficient of the oil film thickness of lubricating oil in the i section roll gap;

d _IjThe working roll temperature field of-Di j section is to the influence coefficient of i section strip steel temperature cross direction profiles.

Formula (2) substitution formula (3), (4) are got:

${\mathrm{\ξ}}_i=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(c_{\mathrm{ij}}\·\underset{k=1}{\overset{N}{\mathrm{\Σ}}}(b_{\mathrm{jk}}\·Q_k))---\left(5\right)$

$T_{\mathrm{bi}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(d_{\mathrm{ij}}\·\underset{k=1}{\overset{N}{\mathrm{\Σ}}}(b_{\mathrm{jk}}\·Q_k))---\left(6\right)$

Band emulsion flow cross direction profiles one is being worked as regularly, the oil film thickness cross direction profiles ξ of lubricating oil in the roll gap as can be seen in through type (5), (6) _i, belt steel temperature cross direction profiles T _BiThe flow distribution that just depends on the working roll emulsion.

Simultaneously, find the functional relation below in cold continuous rolling process, existing between coefficient of friction and the oil film thickness according to theoretical research and lot of data analysis:

${\mathrm{\μ}}_i=a+b\·e^{-c\·{\mathrm{\ξ}}_i}=a+b\·e^{-c\·\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(c_{\mathrm{ij}}\·\underset{k=1}{\overset{N}{\mathrm{\Σ}}}(b_{\mathrm{jk}}\·Q_k))}---\left(7\right)$

In the formula: a-fluid friction coefficient, main relevant with the character of lubricating oil own;

B-dry friction influence coefficient, relevant with the contact condition of deformed area.

C-oil film thickness influence coefficient.

And can know according to pertinent literature, in cold continuous rolling process, characterize laterally the skid characteristic parameter slip factor ψ of probability of each section of band _iCan represent with following formula:

${\mathrm{\ψ}}_i=\frac{1}{4{\mathrm{\μ}}_i}|\sqrt{\frac{\mathrm{\Δ}{h}_i}{{R_i}^{\′}}}+\frac{T_{0i}-T_{1i}}{P_i}|---\left(8\right)$

In the formula: Δ h _i-Di i section passage absolute draft amount;

P _iThe total draught pressure of-Di i section;

R _i'-i section working roll flattens radius, $R^{\&prime;}=R[1+\frac{C_0{P}_i}{B_i\mathrm{\&Delta;}{h}_i}],$ ${\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="A2008102007300022H1.png,A2008102007300022H2.png"\; state="\{\{state\}\}">C</figure-callout>}}_0=\frac{16(1-v^2)}{\mathrm{\&pi;E}}$

(R: working roll radius; E, v: the Young's modulus of working roll and Poisson's ratio, B _i: i section strip width);

T _1i, t _0iThe front and back tension force that-Di i section is total;

Obviously, composite type (6), (7), (8) can be with slip factor ψ _iWrite as Q _jFunction, as the formula (9):

${\mathrm{\&psi;}}_i=\frac{1}{4(a+b\&CenterDot;e^{-c\&CenterDot;\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}(c_{\mathrm{ij}}\&CenterDot;\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}(b_{\mathrm{jk}}\&CenterDot;Q_k))})}|\sqrt{\frac{\mathrm{\&Delta;}{h}_i}{{R_i}^{\&prime;}}}+\frac{T_{0i}-T_{1i}}{P_i}|---\left(9\right)$

Same, characterizing the laterally characteristic parameter slip injury index of the hot sliding injury probability of each section of band

Can represent with following formula:

e _IjThe belt steel surface temperature of-Di j section is to the influence coefficient of i section slip injury index.

According to the flow of metal model in the rolling therory as can be known, the front and back tension force σ of band in cold-rolled process _1i, σ _0iAvailable formula (11) and formula (12) are represented respectively:

${\mathrm{\&sigma;}}_{1i}=\frac{T_1}{B\stackrel{\&OverBar;}{h}}+\frac{E}{1-v^2}[1+\frac{h_i}{\stackrel{\&OverBar;}{h}}-\frac{H_i}{\stackrel{\&OverBar;}{H}}-\frac{L_i}{L}+{u^{\&prime;}}_i-\frac{\mathrm{\&Delta;b}}{B}]---\left(11\right)$

${\mathrm{\&sigma;}}_{0i}=\frac{T_0}{B\stackrel{\&OverBar;}{H}}+\frac{E}{1-v^2}\{\frac{h_i\stackrel{\&OverBar;}{H}[1+{u^{\&prime;}}_i]}{\stackrel{\&OverBar;}{h}{H}_i[1+\frac{\mathrm{\&Delta;b}}{B}]}-\frac{L_i}{L}\}---\left(12\right)$

In the formula: T ₁The total tension force of-outlet side

T ₀The total tension force of-entrance side

The B-strip width

H-band outlet average thickness

h _i-band exit thickness cross direction profiles value

H-band inlet average thickness

H _i-band inlet thickness cross direction profiles value

L-represents to come the length mean value of flitch shape

L _i-expression comes the length cross direction profiles value of flitch shape

U ' _i-band lateral displacement increment cross direction profiles value

Δ b-absolute spread

For cold continuous rolling, consider that the lateral displacement of operation of rolling metal is smaller, thus generally can ignore, so have:

u′ _i≈0 (13)

Δb≈0 (14)

Simultaneously, be convenient research, can be with the inlet thickness cross direction profiles value H of band _iWith strip crown Δ H _iH represents with average thickness, as the formula (15):

$H_i=\mathrm{\&Delta;}{H}_i+\stackrel{\&OverBar;}{H}-\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{H}_i---\left(15\right)$

Like this, wushu (13)-(15) substitution formula (11), (12) then can be with front and back tension force σ _1i, σ _0iThe function representation of difference available formula (16) and formula (17):

σ _1i＝f ₁(h _i，H _i，L _i，B，T ₀，T ₁) (16)

σ _0i＝f ₀(h _i，H _i，L _i，B，T ₀，T ₁) (17)

Equally, according to the roll elastic deformation model in the document plate shape theory as can be known, for the exit thickness distribution value h that rolls the back band _iCan use the function representation of formula (18):

h _i＝f ₃(P，S，ΔD _wi，ΔD _bi，H _i，σ _1i，σ _0i) (18)

In the formula: the total draught pressure of P-

The S-bending roller force

Δ D _Wi, Δ D _BiThe distribution value of-working roll and backing roll roll shape

In formula (18), the roll shape distribution value of working roll can be divided into two parts, and a part is the original roller type of working roll, and a part then is the hot convexity of working roll in addition, represents with formula (19):

ΔD _wi＝ΔD _wyi+ΔD _wti (19)

In the formula: Δ D _WyiThe original roller type of-working roll

Δ D _WtiThe hot convexity of-working roll

Like this, for the cold continuous rolling process of a particular chassis, band supplied materials parameter such as H _i, L _i, B etc. are known, backing roll roll shape Δ D _BiWith working roll original roller type Δ D _WyiDeng determining, if given front and back tension force T ₁, T ₀With technological parameters such as total draught pressure P, and bending roller force S is set in ground state (that is: gets

S _MinThe minimum bending roller force that-milling train allowed, S _MaxThe maximum bending roller force that-milling train allowed.Why bending roller force being set in ground state, is in order to allow bending roller force that bigger adjusting space is arranged), simultaneous formula (16)-(19) can be with the forward pull cross direction profiles value σ of characterization board shape _1iWith one with work roll thermal crown Δ D _WtiFor the function of independent variable is represented, that is:

σ _1i＝g ₀(ΔD _wti) (20)

And can know Δ D according to the analysis of formula (1) _Wti=f ₁(Q _j), it is updated to formula (20), promptly can be with the forward pull cross direction profiles value σ of characterization board shape _1iWith one be that the function of independent variable is represented with the emulsion section flow, that is:

σ _1i＝g(Q _j) j＝1，2，...，N (21)

Can know according to Field Research and theory analysis,, not only will guarantee to export the plate shape precision index of band, the part in the operation of rolling, not occur and skid and localized heat sliding injury phenomenon but also will satisfy band in order to give full play to the effect of segmentation cooling control system.For this reason, emulsion section control object function can simply be defined as:

In the formula: X={Q _jJ=1,2 ..., N}

ψ ^*The critical slip factor of-milling train

The critical slip injury index of-milling train

Like this, tandem cold rolling mill emulsion section mathematics of control model can simply be described as: seek an appropriate emulsified flow quantity distribution setting value X={Q _jJ=1,2 ..., N} makes F (X) minimum.Emulsion section cooling control procedure flow chart as shown in Figure 4.

Embodiment 1

Be that the typical steel grade of AP0740 is an example now, describe emulsion section cooling control procedure and the relevant effect of specific steel grade on specific tandem mills by means of Fig. 4 with the tapping mark.

At first, in the starting stage, the first, collect the device parameter of milling train and the key parameters such as description of band steel to be rolled, mainly comprise working roll barrel length L _W=2230mm, work roll diameter D _W=560mm, backing roll barrel length L _b=2030mm, backing roll diameter D _b=1500mm, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁=2360mm, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂=2360mm, maximum bending roller force S=50t, maximum draught pressure P=3000t, maximum mill speed V=1200m/min, work original roller type Δ D _Wyi=0, backing roll original roller type Δ D _Bi=0, the critical slip factor ψ of milling train ^*=0.41, the critical slip injury index of milling train

Strip width B=1020mm, band outlet average thickness h=0.498mm, band inlet average thickness H=0.501mm, come flitch shape length mean value L=1, come the length cross direction profiles value L of flitch shape _i=0, outlet side tension force T ₁=29Mpa, entrance side tension force T ₀=190Mpa;

In the starting stage, the second, collection process lubricates the system parameter, and the temperature of emulsion is that 55 ℃, concentration are 2%;

Subsequently, in step 1, given emulsion section cooling flow distribution initial value

X ₀={ Q _0jJ=1,2 ..., N}={100,100,100,100,100,100,100,100,100} and iteration precision ε=0.001;

In step 2, calculate corresponding work roll thermal crown

ΔD _wti＝{0，3，6，12，22，45，24，11，5，2，1}；

In step 3, calculate slip factor cross direction profiles value

ψ _i＝{0.3，0.4，0.21，0.29，0.40，0.39，0.35，0.37，0.40}；

Subsequently, in step 4, middle judgement inequality max (ψ _i)≤ψ ^*Whether set up, if set up then change step 5 over to; If be false, then repeating step 2 to 3, till inequality is set up;

In step 5, calculate slip injury index cross direction profiles value

Subsequently, in step 6, judge inequality

Whether set up, if set up then change step 7 over to; If be false, then repeating step 2 to 5, till inequality is set up;

In step 7, calculate respective plate shape distribution value { σ _1i}={ 22,25,29,36,35,32,34,39,41};

In step 8, the functional value that calculates plate shape objective function F (X) is 0.71;

Subsequently, in step 9, judge whether the Powell condition is set up,, repeat above-mentioned steps 2, set up, finish to calculate, draw optimal segmentation cooling flow-control curve, as shown in Figure 5 until the Powell condition to step 8 if be false.

Corresponding with it, in Fig. 5, provide the emulsion section flow curve that draws with conventional method simultaneously.

At last, for convenience relatively, list slip factor, slip injury index that is drawn when adopting emulsion section cooling control method of the present invention and adopting conventional method to set the emulsion flow distribution and the band forward pull cross direction profiles situation that characterizes the finished product strip shape quality respectively, and the actual effect contrast of will being correlated with is as follows:

As shown in Figure 6, provide the slip factor cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 6, adopt emulsion flow control methods of the present invention, slip factor mean value is reduced to 0.24 from 0.33, has reduced by 27.3%; The slip factor maximum is reduced to 0.262 from 0.375, has reduced by 30.1%.Illustrate and adopt the method for the invention to improve rolling stability greatly.

As shown in Figure 7, provide the slip injury index cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 7, adopt emulsion flow control methods of the present invention, slip injury index mean value is reduced to 0.33 from 0.50, has reduced by 34%; The slip injury index maximum is reduced to 0.371 from 0.605, has reduced by 38.7%.Illustrate and adopt the method for the invention to greatly reduce the probability that hot sliding injury takes place, improved the surface quality of band.

As shown in Figure 8, provide the band forward pull cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 8, adopt emulsion flow control methods of the present invention, the degree of irregularity of forward pull cross direction profiles is reduced to 0.24 from 0.46, has reduced by 47.8%.Illustrate that employing the method for the invention greatly reduces the degree of irregularity of forward pull cross direction profiles, has improved the strip shape quality of band.

Embodiment 2

In order further to set forth basic thought of the present invention, be that the typical steel grade of AP1057 is an example with the tapping mark again, by means of Fig. 4 emulsion section cooling control procedure and the relevant effect of specific steel grade on specific tandem mills described.

At first, in the starting stage, the first, collect the device parameter of milling train and the key parameters such as description of band steel to be rolled, mainly comprise working roll barrel length L _W=2230mm, work roll diameter D _W=560mm, backing roll barrel length L _b=2030mm, backing roll diameter D _b=1500mm, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁=2360mm, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂=2360mm, maximum bending roller force S=50t, maximum draught pressure P=3000t, maximum mill speed V=1200m/min, work original roller type Δ D _Wyi=0, backing roll original roller type Δ D _Bi=0, the critical slip factor ψ of milling train ^*=0.41, the critical slip injury index of milling train

Strip width B=1545mm, band outlet average thickness h=1.740mm, band inlet average thickness H=1.823mm, come flitch shape length mean value L=1, come the length cross direction profiles value L of flitch shape _i=0, outlet side tension force T ₁=29Mpa, entrance side tension force T ₀=100Mpa;

In the starting stage, the second, collection process lubricates the system parameter, and the temperature of emulsion is that 53 ℃, concentration are 2.3%;

Subsequently, in step 1, given emulsion section cooling flow distribution initial value

X ₀={ Q _0jJ=1,2 ..., N}={120,120,120,120,120,120,120,120,120} and iteration precision ε=0.001;

In step 2, calculate corresponding work roll thermal crown

ΔD _wti＝{0，4，7，13，23，40，21，14，6，3，2}；

In step 3, calculate slip factor cross direction profiles value

ψ _i＝{0.4，0.3，0.31，0.39，0.35，0.32，0.31，0.34，0.36}；

Subsequently, in step 4, judge inequality max (ψ _i)≤ψ ^*Whether set up, if set up then change step 5 over to; If be false, then repeating step 2 to 3, till inequality is set up;

In step 5, calculate slip injury index cross direction profiles value

Subsequently, in step 6, judge inequality

Whether set up, if set up then change step 7 over to; If be false, then repeating step 2 to 5, till inequality is set up;

In step 7, calculate corresponding plate shape distribution value { σ _1i}={ 32,35,19,26,15,23,24,19,31};

In step 8, the functional value that calculates plate shape objective function F (X) is 0.56;

Subsequently, in step 9, judge whether the Powell condition is set up,, repeat above-mentioned steps 2, set up, finish to calculate, draw optimal segmentation cooling flow-control curve, as shown in Figure 9 until the Powell condition to step 8 if be false.

Same, provide the emulsion section flow curve that adopts conventional method and draw as shown in Figure 9.

At last, for convenience relatively, list slip factor, slip injury index that is drawn when adopting emulsion section cooling control method of the present invention and adopting conventional method to set the emulsion flow distribution and the band forward pull cross direction profiles situation that characterizes the finished product strip shape quality respectively, and the actual effect contrast of will being correlated with is as follows:

As shown in figure 10, provide the slip factor cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 10, adopt emulsion flow control methods of the present invention, slip factor mean value is reduced to 0.254 from 0.452, has reduced by 43.8%; The slip factor maximum is reduced to 0.287 from 0.5, has reduced by 42.6%.Illustrate and adopt the method for the invention to improve rolling stability greatly.

As shown in figure 11, provide the slip injury index cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 11, adopt emulsion flow control methods of the present invention, slip injury index mean value is reduced to 0.368 from 0.589, has reduced by 37.5%; The slip injury index maximum is reduced to 0.421 from 0.7, has reduced by 39.9%.Illustrate and adopt the method for the invention to greatly reduce the probability that hot sliding injury takes place, improved the surface quality of band.

As shown in figure 12, provide the band forward pull cross direction profiles situation that adopts emulsion control method of the present invention and conventional method respectively.As seen in Figure 12, adopt emulsion flow control methods of the present invention, the degree of irregularity of forward pull cross direction profiles is reduced to 0.13 from 0.40, has reduced by 67.5%.Illustrate that employing the method for the invention greatly reduces the degree of irregularity of forward pull cross direction profiles, has improved the strip shape quality of band.

Claims (8)

1, a kind of control method of tandem cold rolling mill emulsion section cooling is characterized in that: may further comprise the steps:

(a) collect the device parameter of milling train and the key parameter of band steel to be rolled;

(b) the lubricated system parameter of collection process;

(c) given emulsion section cooling flow distribution initial value X ₀={ Q _0jJ=1,2 ..., N} and initial step length and termination precision;

(d) calculate corresponding work roll thermal crown Δ D _Wti

(e) calculate slip factor cross direction profiles value ψ _i

(f) judge inequality max (ψ _i)≤ψ ^*Whether set up, if set up then change step (g) over to; If be false, then repeating step (d) is to (e), till inequality is set up;

(g) calculate slip injury index cross direction profiles value

(h) judge inequality

Whether set up, wherein:

Be the critical slip injury index of milling train, if set up then change step (I) over to; If be false, then repeating step (d) is to (g), till inequality is set up;

(i) calculate corresponding plate shape distribution value σ _1i

(j) functional value of calculating plate shape objective function F (X);

(k) judge whether the Powell condition is set up,, repeat above-mentioned steps (d), set up, finish to calculate, draw optimal segmentation cooling flow-control curve until the Powell condition to step (j) if be false.

2, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: the device parameter of milling train comprises described in the step (a): working roll barrel length L _W, work roll diameter D _W, backing roll barrel length L _b, backing roll diameter D _b, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂, maximum bending roller force S, maximum draught pressure P, maximum mill speed V, work original roller type Δ D _Wyi, backing roll original roller type Δ D _Bi, the critical slip factor ψ of milling train ^*, the critical slip injury index of milling train

3, control method of tandem cold rolling mill emulsion section cooling according to claim 1, it is characterized in that: the key parameter of band steel to be rolled comprises described in the step (a): strip width B, band outlet average thickness h, band inlet average thickness H, come the length mean value L of flitch shape, come the length cross direction profiles value L of flitch shape _i, the total tension force T of outlet side ₁, the total tension force T of entrance side ₀

4, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: technological lubrication system parameter comprises described in the step (b): the temperature of emulsion, concentration.

5, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: the calculating of work roll thermal crown described in the step (d) is adopted with drag:

$\mathrm{\&Delta;}{D}_{\mathrm{wti}}=\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}(a_{\mathrm{ij}}\&CenterDot;Q_j)$ j＝1，2，…，N

N-emulsion cooling hop count in the formula;

Q _jThe emulsion flow of-Di j section;

a _IjThe emulsion flow of-Di j section is to the influence coefficient of i section work roll thermal crown;

Δ D _Wti-work roll thermal crown.

6, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: slip factor ψ described in the step (e) _iCalculating adopt with drag:

${\mathrm{\&psi;}}_i=\frac{1}{4(a+b\&CenterDot;e^{-\underset{j=1}{\overset{N}{\mathrm{\&Sigma;}}}(c_{\mathrm{ij}}\&CenterDot;\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}(b_{\mathrm{jk}}\&CenterDot;Q_k))})}|\sqrt{\frac{\mathrm{\&Delta;h}}{{R_i}^{\&prime;}}}+\frac{T_{0i}-T_{1i}}{P_i}|$

In the formula: a-fluid friction coefficient, main relevant with the character of lubricating oil own;

B-dry friction influence coefficient, relevant with the contact condition of deformed area;

C-oil film thickness influence coefficient;

Δ h _i-Di i section passage absolute draft amount;

P _iThe total draught pressure of-Di i section;

R _i'-i section working roll flattens radius

c _IjThe working roll temperature field of-Di j section is to the influence coefficient of the oil film thickness of lubricating oil in the i section roll gap;

b _IjThe emulsion flow of-Di j section is to the influence coefficient in i section working roll temperature field.

7, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: slip injury index cross direction profiles value described in the step (g) Calculating adopt with drag:

In the formula: d _IjThe working roll temperature field of-Di j section is to i section strip steel temperature cross direction profiles influence coefficient;

e _IjThe belt steel surface temperature of-Di j section is to the influence coefficient of i section slip injury index.

8, control method of tandem cold rolling mill emulsion section cooling according to claim 1 is characterized in that: the calculating of the functional value of plate shape objective function F (X) described in the step (j) is adopted with drag:

F(X)＝((max(σ _1i)-min(σ _1i))/T ₁)

In the formula: T ₁The total tension force of-outlet side;

σ _1i-exit plate shape value, can represent in order to following equation:

${\mathrm{\&sigma;}}_{\mathrm{li}}=\frac{T_1}{B\stackrel{\&OverBar;}{h}}+\frac{E}{1-v^2}[1+\frac{h_i}{\stackrel{\&OverBar;}{h}}-\frac{H_i}{\stackrel{\&OverBar;}{H}}-\frac{L_i}{L}+{u^{\&prime;}}_i-\frac{\mathrm{\&Delta;b}}{B}]$

In the formula: T ₀The total tension force of-entrance side,

The B-strip width,

H-band outlet average thickness,

h _i-band exit thickness cross direction profiles value,

H-band inlet average thickness,

H _i-band inlet thickness cross direction profiles value,

L-represents to come the length mean value of flitch shape,

L _i-expression comes the length cross direction profiles value of flitch shape,

U ' _i-band lateral displacement increment cross direction profiles value,

Δ b-absolute spread.

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