EMULSION FLOW OPTIMIZATION METHOD FOR SUPPRESING VIBRATION OF COLD CONTINUOUS ROLLING MILL

Abstract

An emulsion flow optimization method suitable for a cold continuous rolling mill that aims to achieve vibration suppression. Said method aims to suppress vibrations, and by means of an oil film thickness model and a friction coefficient model, an optimum set value of the emulsion flow rate for each rolling stand that aims to achieve vibration suppression is optimized on the basis of an over-lubrication film thickness critical value and an under-lubrication film thickness critical value that are proposed. The described method greatly reduces the incidence of rolling mill vibration defects, improves production efficiency and product quality, treats rolling mill vibration defects, and improves the surface quality and rolling process stability of a finished strip of a cold continuous rolling mill.

Claims

1. An emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill, characterized by comprising the following steps: (S1) collecting device feature parameters of the cold continuous rolling mill, wherein the device feature parameters comprise: the radius R.sub.i of a working roll of each rolling stand, the surface linear velocity ν.sub.ri of a roll of each rolling stand, the original roughness Ra.sub.ir0 of a working roll of each rolling stand, roughness attenuation coefficient B.sub.L of a working roll, the distance l between rolling stands, and the rolling kilometer L.sub.i after roll change of a working roll of each rolling stand, wherein i is 1, 2, . . . , n, and represents the ordinal number of the rolling stands of the cold continuous rolling mill, and n is the total number of rolling stands; (S2) collecting key rolling process parameters of a strip, wherein the key rolling process parameters comprise: the inlet thickness h.sub.0i of each rolling stand, the outlet thickness h.sub.1i of each rolling stand, strip width B, the inlet speed ν.sub.0i of each rolling stand, the outlet speed ν.sub.1i of each rolling stand, the inlet temperature T.sub.1.sup.r, strip deformation resistance K.sub.i of each rolling stand, rolling pressure P.sub.i of each rolling stand, back tension T.sub.0i of each rolling stand, front tension T.sub.1i of each rolling stand, emulsion concentration influence coefficient k.sub.c, pressure-viscosity coefficient θ of a lubricant, strip density ρ, specific heat capacity S of a strip, emulsion concentration C, emulsion temperature T.sub.c and thermal-work equivalent J; (S3) defining process parameters involved in the emulsion flow optimization process, wherein the process parameters comprise an over-lubrication film thickness critical value ξ.sub.i.sup.+ of each rolling stand, the friction coefficient u.sub.i.sup.+ at this time, an under-lubrication film thickness critical value ξ.sub.i.sup.− and the friction coefficient u.sub.i.sup.− at this time, the rolling reduction amount Δh.sub.i (wherein Δh.sub.i=h.sub.0i−h.sub.1i), the rolling reduction rate ε.sub.i (wherein ${\mathrm{.Math.}}_i=\frac{\Delta h_i}{h_{0i}}),$ the inlet temperature T.sub.i.sup.r of each rolling stand, the over-lubrication judgment coefficient A.sup.+, and the under-lubrication judgment coefficient A.sup.−, and evenly dividing the distance l between the rolling stands into m sections, wherein the temperature in the sections is represented by T.sub.i,j (wherein 1≤j≤m), and T.sub.i.sup.r=T.sub.i−1,m); (S4) setting the initial set value of an emulsion flow rate comprehensive optimization objective function of the cold continuous rolling mill for achieving vibration suppression as F.sub.0=1.0×10.sup.10; wherein the executing order of steps S1-S4 is not limited; (S5) calculating the bite angle α.sub.i of each rolling stand according to the rolling theory, wherein the calculation formula is as follows: ${\alpha }_i=\sqrt{\frac{\Delta h_i}{R_i^{\prime }}},$ R.sub.i′ is the flattening radius of the working roll of the i.sup.th rolling stand, and is a calculation process value of rolling pressure; (S6) calculating the vibration determination index reference value ξ.sub.0i of each rolling stand; (S7) setting the emulsion flow rate w.sub.i of each rolling stand; (S8) calculating the strip outlet temperature T.sub.i of each rolling stand; (S9) calculating an emulsion flow rate comprehensive optimization objective function F(X); $\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array};$ (S10) determining whether the in-equation F(X)<F.sub.0 is established, if yes, enabling w.sub.i.sup.y=w.sub.i, F.sub.0=F(X), and turning to step S11; otherwise, directly turning to step S11; (S11) determining whether the emulsion flow rate w.sub.i exceeds a feasible region range, if yes, turning to step S12, otherwise, turning to step S7, wherein the feasible region of w.sub.i ranges from 0 to the maximum emulsion flow rate value allowed by the rolling mill; and (S12) outputting an optimum emulsion flow rate set value w.sub.i.sup.y, wherein w.sub.i.sup.y is the value of w.sub.i when the calculated value of F(X) in the feasible region is minimum.

2. The emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill according to claim 1, characterized in that, the step S6 comprises the following steps: (S6.1) calculating the neutral angle γ.sub.i of each rolling stand: ${\gamma }_i=\frac{1}{2}\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}\left[1+\frac{1}{2u_i}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)\right];$ (S6.2) calculating to obtain $u_i^{+}=\frac{1}{2\left(2A^{+}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$ from the step S5 and the step S6.1 assuming that when $\frac{{\gamma }_i}{{\alpha }_i}=A^{+},$ the roll gap is just in an over-lubrication state; (S6.3) calculating an over-lubrication film thickness critical value ξ.sub.i.sup.+ of each rolling stand according to the relation formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i (in the formula, a.sub.i is a liquid friction influence coefficient, b.sub.i is a dry friction influence coefficient, and B.sub.i is a friction coefficient attenuation index), wherein ${\xi }_i^{+}=\frac{1}{B_i}\ln \frac{u_i^{+}-a_i}{b_i};$ (S6.4) calculating to obtain $u_i^{-}=\frac{1}{2\left(2A^{-}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$ from the step S5 and the step S6.1 assuming that when $\frac{{\gamma }_i}{{\alpha }_i}=A^{-},$ the roll gap is just in an under-lubrication state; (S6.5) calculating an under-lubrication film thickness critical value ξ.sub.i.sup.− of each rolling stand according to the relation formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i, wherein ${\xi }_i^{-}=\frac{1}{B_i}\ln \frac{u_i^{-}-a_i}{b_i};$ and (S6.6) calculating the vibration determination index reference value ξ.sub.0i, wherein ${\xi }_{0i}=\frac{{\xi }_i^{+}+{\xi }_i^{-}}{2}.$

3. The emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill according to claim 2, characterized in that, the step S8 comprises the following steps: (S8.1) calculating the outlet temperature T.sub.1 of the first rolling stand, wherein $T_1=T_1^r+\frac{1-\left({\mathrm{.Math.}}_1/4\right)}{1-\left({\mathrm{.Math.}}_1/2\right)}.Math.\frac{K_1\ln \left(\frac{1}{1-{\mathrm{.Math.}}_1}\right)}{\rho \mathrm{SJ}};$ (S8.2) enabling i=1; (S8.3) calculating the temperature T.sub.i,1 of the first section of strip behind the outlet of the i.sup.th rolling stand, i.e. T.sub.i,1=T.sub.i; (S8.4) enabling j=2; (S8.5) calculating the temperature T.sub.i,j of the j.sup.th section of strip by the relationship between the temperature of the j.sup.th section and the temperature of the j−1.sup.th section shown by the following equation: $T_{i,j}=-\frac{2k_0{w}_i^{0.264}\exp \left(9.45-0.1918C.\right)\times 1.163l}{v_{1i}{h}_{1i}\rho Sm}{T}_{i,j-1}^{-0.213}\left(T_{i,j-1}-T_c\right)+T_{i,j-1},$ wherein k.sub.0 is the influence coefficient of nozzle shape and spraying angle; (S8.6) determining whether the in-equation j<m is established, if yes, enabling j=j+1, and then turning to step S8.5; otherwise, turning to step S8.7; (S8.7) obtaining the temperature T.sub.i,m of the m.sup.th section by iterative calculation; (S8.8) calculating the inlet temperature T.sub.i+1.sup.r of the i+1.sup.th rolling stand: T.sub.i+1.sup.r=T.sub.i,m; (S8.9), calculating the outlet temperature T.sub.i+1 of the i+1.sup.th rolling stand, wherein $T_{i+1}=T_{i+1}^r+\frac{1-\left({\mathrm{.Math.}}_{i+1}/4\right)}{1-\left({\mathrm{.Math.}}_{i+1}/2\right)}.Math.\frac{K_{i+1}\ln \left(\frac{1}{1-{\mathrm{.Math.}}_{i+1}}\right)}{\rho \mathrm{SJ}};$ (S8.10) determining whether the in-equation i<n is established, if yes, enabling i=i+1, and then turning to step S8.3; otherwise, turning to step S8.11; and (S8.11) obtaining the outlet temperature T.sub.i of each rolling stand.

4. The emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill according to claim 3, characterized in that, the step S9 comprises the following steps: (S9.1) calculating the dynamic viscosity η.sub.0i of an emulsion between roll gaps of each rolling stand, wherein η.sub.0i=b.Math.exp(−a.Math.T.sub.i), and in the formula, a,b are dynamic viscosity parameters of lubricating oil under the atmospheric pressure; (S9.2) calculating the oil film thickness ξ.sub.i between roll gaps of each rolling stand, wherein the calculation formula is as follows: ${\xi }_i=\frac{h_{0i}+h_{1i}}{2h_{0i}}.Math.k_c.Math.\frac{3\theta {\eta }_{0i}\left(v_{\mathrm{ri}}+v_{0i}\right)}{{\alpha }_i\left[1-e^{-\theta \left(K-\frac{T_{0i}}{h_{0i}.Math.B}\right)}\right]}-k_{rg}.Math.\left(1+K_{rs}\right).Math.{\mathrm{Ra}}_{\mathrm{ir}0}.Math.e^{-B_L.Math.L_i}$ in the formula, k.sub.rg represents the coefficient of the strength of entrainment of lubricant by the longitudinal surface roughness of the work roll and the strip steel and is in the range of 0.09-0.15, K.sub.rs represents the impression rate, namely the ratio of transferring the surface roughness of the working roll to the strip; and (S9.3) calculating an emulsion flow rate comprehensive optimization objective function, $\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array}\hspace{1em}$ in the formula, X={w.sub.i} is an optimization variable, and λ is a distribution coefficient.

5. The emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill according to claim 3, characterized in that, 0.8<k.sub.0<1.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In the present invention, the same reference numerals always represent the same features, wherein:

[0055] FIG. 1 is a flowchart of an emulsion flow optimization method of the present invention;

[0056] FIG. 2 is a flowchart of calculating the vibration determination index reference value;

[0057] FIG. 3 is a flowchart of calculating the strip outlet temperature of each rolling stand; and

[0058] FIG. 4 is a flowchart of calculating an emulsion flow comprehensive optimization objective function.

DETAILED DESCRIPTION

[0059] The technical solution of the present invention will be further described in combination with the drawings and the embodiments.

[0060] Rolling mill vibration defects are very easily caused between roll gaps of each rolling stand of a cold continuous rolling mill, whether in an over-lubrication state or in an under-lubrication state, and the setting of the emulsion flow rate directly affects the lubrication state between the roll gaps of each rolling stand. In order to realize the treatment of the rolling mill vibration defects, starting from the emulsion flow rate, this patent ensures that both the overall lubrication state of the cold continuous rolling mill and the lubrication state of individual rolling stands can be optimum through the comprehensive optimal distribution of the emulsion flow rate of the cold continuous rolling mill, so as to achieve the goal of treating the rolling mill vibration defects, improving the surface quality and rolling process stability of a finished strip of the cold continuous rolling mill.

[0061] Referring to FIG. 1, an emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill includes the following steps:

[0062] S1, collecting device feature parameters of the cold continuous rolling mill, wherein the device feature parameters include: the radius R.sub.i of a working roll of each rolling stand, the surface linear velocity ν.sub.ri of a roll of each rolling stand, the original roughness Ra.sub.ir0 of a working roll of each rolling stand, the roughness attenuation coefficient B.sub.L of a working roll, the distance l between rolling stands, and the rolling kilometer L.sub.i after roll change of a working roll of each rolling stand, wherein i is 1, 2, . . . , n, and represents the ordinal number of rolling stands of the cold continuous rolling mill, and n is the total number of rolling stands;

[0063] S2, collecting key rolling process parameters of a strip, wherein the key rolling process parameters include: the inlet thickness h.sub.0i of each rolling stand, the outlet thickness h.sub.1i of each rolling stand, strip width B, the inlet speed ν.sub.0i of each rolling stand, the outlet speed ν.sub.1i of each rolling stand, the inlet temperature T.sub.1.sup.r, strip deformation resistance K.sub.i of each rolling stand, rolling pressure P.sub.i of each rolling stand, back tension T.sub.0i of each rolling stand, front tension T.sub.1i of each rolling stand, emulsion concentration influence coefficient k.sub.c, pressure-viscosity coefficient θ of a lubricant, strip density ρ, specific heat capacity S of a strip, emulsion concentration C, emulsion temperature T.sub.c and thermal-work equivalent J;

[0064] S3, defining process parameters involved in the process of emulsion flow optimization, wherein the process parameters include that an over-lubrication film thickness critical value of each rolling stand is ξ.sub.i.sup.+ and the friction coefficient at this time is u.sub.i.sup.+, an under-lubrication film thickness critical value is ξ.sub.i.sup.+ and the friction coefficient at this time is u.sub.i.sup.−, the rolling reduction amount is Δh.sub.i=h.sub.0i−h.sub.1i, the rolling reduction rate is

[00017]${\mathrm{.Math.}}_i=\frac{\Delta h_i}{h_{0i}},$

[0065] the inlet temperature of each rolling stand is T.sub.i.sup.r, the distance l between the rolling stands is evenly divided into m sections, and the temperature in the sections is represented by T.sub.i,j(wherein, 1≤j≤m), and T.sub.i.sup.r=T.sub.i−1,m, the over-lubrication judgment coefficient is A.sup.+, and the under-lubrication judgment coefficient is A.sup.−;

[0066] S4, setting the initial set value of an emulsion flow rate comprehensive optimization objective function of the cold continuous rolling mill that aims to achieve vibration suppression as F.sub.0=1.0×10.sup.10;

[0067] the executing order of steps S1 to S4 is not limited, and in some cases, steps S1 to S4 can be performed simultaneously.

[0068] S5, calculating the bite angle α.sub.i of each rolling stand according to the rolling theory, wherein the calculation formula is as follows:

[00018]${\alpha }_i=\sqrt{\frac{\Delta h_i}{R_i^{\prime }}},$

[0069] R.sub.i′ is the flattening radius of the working roll of the i.sup.th rolling stand, and is the calculation process value of rolling pressure;

[0070] S6, calculating the vibration determination index reference value ξ.sub.0i of each rolling stand, wherein the calculation flowchart is shown in FIG. 2:

[0071] S6.1, calculating the neutral angle γ.sub.i of each rolling stand:

[00019]${\gamma }_i=\frac{1}{2}\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}\left[1+\frac{1}{2u_i}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)\right];$

[0072] S6.2, calculating to obtain

[00020]$u_i^{+}=\frac{1}{2\left(2A^{+}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0073] from steps S5 and S6.1 assuming that when

[00021]$\frac{{\gamma }_i}{{\alpha }_i}=A^{+},$

[0074] the roll gap is Just in an over-lubrication state;

[0075] S6.3, calculating an over-lubrication film thickness critical value ξ.sub.i.sup.+ of each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, namely u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i (in the formula, a.sub.i is the liquid friction influence coefficient, b.sub.i is the dry friction influence coefficient, and B.sub.i is the friction coefficient attenuation index), wherein

[00022]${\xi }_i^{+}=\frac{1}{B_i}\ln \frac{u_i^{+}-a_i}{b_i};$

[0076] S6.4, calculating to obtain

[00023]$u_i^{-}=\frac{1}{2\left(2A^{-}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0077] from steps S5 and S6.1 assuming that when

[00024]$\frac{{\gamma }_i}{{\alpha }_i}=A^{-},$

[0078] the roll gap is just in an under-lubrication state;

[0079] S6.5, calculating an under-lubrication film thickness critical value of ξ.sub.i.sup.− each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, namely u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i, wherein

[00025]${\xi }_i^{-}=\frac{1}{B_i}\ln \frac{u_i^{-}-a_i}{b_i};$

[0080] and

[0081] S6.6, calculating the vibration determination index reference value ξ.sub.0i of each rolling stand, wherein

[00026]${\xi }_{0i}\frac{{\xi }_i^{+}+{\xi }_i^{-}}{2};$

[0082] S7, setting the emulsion flow rate w.sub.i of each rolling stand;

[0083] S8, calculating the strip outlet temperature T.sub.i of each rolling stand, wherein the calculation flowchart is shown in FIG. 3,

[0084] S8.1, calculating the outlet temperature T.sub.1 of the first rolling stand, wherein

[00027]$T_1=T_1^r+\frac{1-\left({\mathrm{.Math.}}_1\text{/}4\right)}{1-\left({\mathrm{.Math.}}_1\text{/}2\right)}.Math.\frac{K_1\ln \left(\frac{1}{1-{\mathrm{.Math.}}_1}\right)}{\rho SJ};$

[0085] S8.2, enabling i=1;

[0086] S8.3, calculating the temperature T.sub.i,1 of the first section of strip behind the outlet of the i.sup.th rolling stand, i.e. T.sub.i,1=T.sub.i;

[0087] S8.4, enabling j=2;

[0088] S8.5, showing the relationship between the temperature of the j.sup.th section and the temperature of the j−1.sup.th section by the following equation:

[00028]$T_{i,j}=-\frac{2k_0{w}_i^{0.264}\exp \left(9.45-0.1918C\right)\times 1.163l}{v_{1i}{h}_{1i}\rho Sm}{T}_{i,j-1}^{-0.213}\left(T_{i,j-1}-T_c\right)+T_{i,j-1},$

[0089] wherein k.sub.0 is the influence coefficient of the nozzle shape and spraying angle, and 0.8<k.sub.0<1.2;

[0090] S8.6, determining whether the in-equation j<m is established, if yes, enabling j=j+1, and then turning to step S8.5; otherwise, turning to step S8.7;

[0091] S8.7, obtaining the temperature T.sub.i,m of the m.sup.th section by iterative calculation;

[0092] S8.8, calculating the inlet temperature T.sub.i+1.sup.r of the i+1.sup.th rolling stand: T.sub.i+1.sup.r=T.sub.i,m;

[0093] S8.9, calculating the outlet temperature T.sub.i+1 of the i+1.sup.th rolling stand, wherein

[00029]$T_{i+1}=T_{i+1}^r+\frac{1-\left({\mathrm{.Math.}}_{i+1}\text{/}4\right)}{1-\left({\mathrm{.Math.}}_{i+1}\text{/}2\right)}.Math.\frac{K_{i+1}\ln \left(\frac{1}{1-{\mathrm{.Math.}}_{i+1}}\right)}{\rho \mathrm{SJ}};$

[0094] S8.10, determining whether the in-equation i<n is established, if yes, enabling i=i+1, and then turning to step S8.3; otherwise, turning to step S8.11; and

[0095] S8.11, obtaining the outlet temperature T.sub.i of each rolling stand;

[0096] S9, calculating an emulsion flow rate comprehensive optimization objective function F(X), wherein the calculation flowchart is shown in FIG. 4,

[0097] S9.1, calculating the dynamic viscosity η.sub.0i, of an emulsion between roll gaps of each rolling stand, wherein η.sub.0ib.Math.exp(−a.Math.T.sub.i), in the formula, a,b are the dynamic viscosity parameters of lubricating oil under atmospheric pressure;

[0098] S9.2, calculating the oil film thickness ξ.sub.i between the roll gaps of each rolling stand, wherein the calculation formula is as follows:

[00030]${\xi }_i=\frac{h_{0i}+h_{1i}}{2h_{0i}}.Math.k_c.Math.\frac{3\theta {\eta }_{0i}\left(v_{\mathrm{ri}}+v_{0i}\right)}{{\alpha }_i[1-e^{-\theta \left(K-\frac{T_{0i}}{h_{0i}.Math.B}\right)}]}-k_{\mathrm{rg}}.Math.\left(1+K_{\mathrm{rs}}\right).Math.{\mathrm{Ra}}_{\mathrm{ir}0}.Math.e^{-B_L.Math.L_i}$

[0099] in the formula, k.sub.rg represents the coefficient of the strength of entrainment of lubricant by the longitudinal surface roughness of the work roll and the strip steel, and is in the range of 0.09-0.15, and K.sub.rs represents the impression rate, that is, the ratio of transferring the surface roughness of the working roll to the strip; and

[0100] S9.3, calculating an emulsion flow rate comprehensive optimization objective function:

[00031]$\hspace{1em}\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array}$

[0101] in the formula, X={w.sub.i} is the optimization variable and λ is the distribution coefficient;

[0102] S10, determining whether the in-equation F(X)<F.sub.0 is established, if yes, enabling w.sub.i.sup.y=w.sub.i,F.sub.0=F(X), and then turning to step S11; otherwise, turning directly to step S11;

[0103] S11, determining whether the emulsion flow rate w.sub.i exceeds the a feasible region range, if yes, turning to step S12; otherwise, turning to step S7, wherein the feasible region of w.sub.i ranges from 0 to the maximum emulsion flow rate value allowed by the rolling mill.

[0104] S12, outputting an optimal emulsion flow rate set value w.sub.i.sup.y, wherein w.sub.i.sup.y is the value of w.sub.i when the calculated value of F(X) in the feasible region is minimum.

Embodiment 1

[0105] In order to further explain the application process of the related technology of the present application, the application process of an emulsion flow optimization method for a cold continuous rolling mill that aims to achieve vibration suppression is described by taking a 1730 cold continuous rolling mill in a cold rolling plant as an example.

[0106] An emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill includes the following steps:

[0107] S1, collecting device feature parameters of the cold continuous rolling mill, wherein the 1730 cold continuous rolling mill in a cold rolling plant has 5 rolling stands in total, and the device feature parameters mainly include: the radius R.sub.i={210,212,230,230,228} mm of a working roll of each rolling stand, the surface linear velocity ν.sub.ri={180,320,500,800,1150} m/min of a roll of each rolling stand, the original roughness Ra.sub.ir0={1.0,1.0,0.8,0.8,1.0} um of a working roll of each rolling stand, the roughness attenuation coefficient B.sub.L=0.01 of a working roll, the distance l=2700 mm between rolling stands, and the rolling kilometer L.sub.i={100,110,230,180,90} km after roll change of a working roll of each rolling stand, wherein i is 1, 2, . . . , n, and represents the ordinal number of rolling stands of the cold continuous rolling mill, and n=5 is the total number of rolling stands, the same below;

[0108] S2, collecting key rolling process parameters of a strip, wherein the key rolling process parameters mainly include: the inlet thickness h.sub.0i={2.0,1.14,0.63,0.43,0.28} mm of each rolling stand, the outlet thickness h.sub.1i={1.14,0.63,0.43,0.28,0.18} mm of each rolling stand, strip width B=966 mm, the inlet speed ν.sub.0i={110,190,342,552,848} m/min of each rolling stand, the outlet speed ν.sub.1i={190,342,552,848,1214} m/min of each rolling stand, the inlet temperature T.sub.1.sup.r=110° C., strip deformation resistance K.sub.i={360,400,480,590,650} MPa of each rolling stand, rolling pressure P.sub.i={12800,11300,10500,9600,8800} kN of each rolling stand, back tension T.sub.0i{70,145,208,202,229} MPa of each rolling stand, front tension T.sub.1i={145,208,202,229,56} MPa of each rolling stand, emulsion concentration influence coefficient k.sub.c=0.9, pressure-viscosity coefficient θ=0.034 of a lubricant, strip density ρ=7800 kg/m.sup.3, specific heat capacity S=0.47 kJ/(kg.Math.° C.) of a strip, emulsion concentration C=4.2%, emulsion temperature T.sub.c=58° C. and thermal-work equivalent J=1;

[0109] S3, defining process parameters involved in the process of emulsion flow optimization, wherein the process parameters mainly include that an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand is and the friction coefficient at this time is u.sub.i.sup.+, an under-lubrication film thickness critical value is ξ.sub.i.sup.− and the friction coefficient at this time is u.sub.i.sup.−, the rolling reduction amount is Δh.sub.i=h.sub.0i−h.sub.1i, the rolling reduction rate is

[00032]${\mathrm{.Math.}}_i\frac{\Delta h_i}{h_{0i}},$

[0110] the inlet temperature of each rolling stand is T.sub.i.sup.r, and the distance l=2700 mm between the rolling stands is evenly divided into m=30 sections, and the temperature in the sections is represented by T.sub.i,j (wherein, 1≤j≤m), and T.sub.i.sup.r=T.sub.i−1,m, the over-lubrication judgment coefficient is A.sup.+, and the under-lubrication judgment coefficient is A.sup.−;

[0111] S4, setting the initial set value of an emulsion flow rate comprehensive optimization objective function of a cold continuous rolling mill that aims to achieve vibration suppression as F.sub.0=1.0×10.sup.10;

[0112] S5, calculating the bite angle α.sub.i of each rolling stand according to the rolling theory, wherein the calculation formula is

[00033]${\alpha }_i=\sqrt{\frac{\Delta h_i}{R_i^{\prime }}},$

[0113] from which it can be obtained that α.sub.i=10.0556,0.0427,0.0258,0.0223,0.01841;

[0114] S6, calculating the vibration determination index reference value ξ.sub.0i of each rolling stand;

[0115] S6.1, calculating the neutral angle γ.sub.i of each rolling stand, wherein the calculation formula is

[00034]${\gamma }_i=\frac{1}{2}\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}\left[1+\frac{1}{2u_i}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)\right];$

[0116] S6.2, calculating to obtain u.sub.i.sup.+={0.0248,0.0186,0.0132,0.0136,0.0191} according to the formula

[00035]$u_i^{+}=\frac{1}{2\left(2A^{+}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0117] from steps S5 and S6.1 assuming that when

[00036]$\frac{{\gamma }_i}{{\alpha }_i}=A^{+}=1,$

[0118] the roll gap is just in an over-lubrication state;

[0119] S6.3, calculating an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i (in the formula, a.sub.i is the liquid friction influence coefficient, a.sub.i=0.0126, b.sub.i is the dry friction influence coefficient, b.sub.i=0.1416, and B.sub.i is the friction coefficient attenuation index, B.sub.i=−2.4297), wherein the calculation formula is

[00037]${\xi }_i^{+}=\frac{1}{B_i}\ln \frac{u_i^{+}-a_i}{b_i},$

[0120] from which it can be obtained that: ξ.sub.i.sup.−={1.009,1.301,2.249,2.039,1.268} um;

[0121] S6.4, calculating to obtain u.sub.i.sup.−={0.1240,0.0930,0.0660,0.0680,0.0955} according to the formula

[00038]$u_i^{-}=\frac{1}{2\left(2A^{-}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0122] from steps S5 and S6.1 assuming that when

[00039]$\frac{{\gamma }_i}{{\alpha }_i}=A^{-}=0.6,$

[0123] the roll gap is just in an under-lubrication state;

[0124] S6.5, calculating an under-lubrication film thickness critical value of ξ.sub.i.sup.− each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i, wherein the calculation formula is

[00040]${\xi }_i^{-}=\frac{1}{B_i}\ln \frac{u_i^{-}-a_i}{b_i},$

[0125] from which it can be obtained that: ξ.sub.i.sup.−={0.098,0.233,0.401,0.386,0.220} um;

[0126] S6.6, calculating the vibration determination index reference value ξ.sub.0i, wherein

[00041]${\xi }_{0i}=\frac{{\xi }_i^{+}+{\xi }_i^{-}}{2},$

[0127] from which it can be obtained that: ξ.sub.0i={0.554,0.767,1.325,1.213,0.744};

[0128] S7. Setting the emulsion flow rate of each rolling stand to be w.sub.i={900,900,900,900,900} L/min;

[0129] S8, calculating the strip outlet temperature T.sub.i of each rolling stand,

[0130] S8.1, calculating the outlet temperature T.sub.1 of the first rolling stand,

[00042]$T_1=T_1^r+\frac{1-\left({\mathrm{.Math.}}_1/4\right)}{1-\left({\mathrm{.Math.}}_1/2\right)}.Math.\frac{K_1\ln \left(\frac{1}{1-{\mathrm{.Math.}}_1}\right)}{\rho \mathrm{SJ}}=110+\frac{1-\left(0.43/4\right)}{1-\left(0.43/2\right)}.Math.\frac{360\ln \left(\frac{1}{1-0.43}\right)}{7.8.Math.0.47.Math.1}=172.76°C.$

[0131] S8.2, enabling i=1;

[0132] S8.3, calculating the temperature T.sub.1,1, of the first section of strip behind the outlet of the first rolling stand, i.e. T.sub.i,1=T.sub.i=172.76° C.;

[0133] S8.4, enabling j=2;

[0134] S8.5, showing the relationship formula between the temperature of the j.sup.th section and the temperature of the j−1.sup.th section by the following equation:

[00043]$T_{i,j}=-\frac{2k_0{w}_i^{0.264}\exp \left(9.45-0.1918C.\right)\times 1.163l}{v_{1i}{h}_{1i}\rho Sm}{T}_{i,j-1}^{-0.213}\left(T_{i,j-1}-T_c\right)+T_{i,j-1},$

[0135] wherein k.sub.0=1.0;

[0136] S8.6, determining whether the in-equation j<m is established: if yes, enabling j=j+1. and then turning to step S8.5; otherwise, turning to step S8.7;

[0137] S8.7, obtaining the temperature T.sub.1,30=103.32° C. of the m=30.sup.th section by iterative calculation finally;

[0138] S8.8, calculating the inlet temperature T.sub.2.sup.r of the second rolling stand: T.sub.2.sup.r=T.sub.1,m=103.32° C.;

[0139] S8.9, calculating the outlet temperature T.sub.2 of the second rolling stand:

[00044]$T_2=T_2^r+\frac{1-\left({\mathrm{.Math.}}_2/4\right)}{1-\left({\mathrm{.Math.}}_2/2\right)}.Math.\frac{K_2\ln \left(\frac{1}{1-{\mathrm{.Math.}}_2}\right)}{\rho \mathrm{SJ}}=103.32+\frac{1-\left(0.45/4\right)}{1-\left(0.45/2\right)}.Math.\frac{400\ln \left(\frac{1}{1-0.45}\right)}{7800.Math.0.47.Math.1}=178.02°C.;$

[0140] S8.10, determining whether the in-equation i<n is established: if yes, enabling i=i+1, and then turning to step S8.3; otherwise, turning to step S8.11;

[0141] S8.11, obtaining the outlet temperature T.sub.i={172.76,178.02,186.59,194.35,206.33}° C. of each rolling stand;

[0142] S9, calculating an emulsion flow rate comprehensive optimization objective function F(X);

[0143] S9.1, calculating the dynamic viscosity η.sub.0i of an emulsion between roll gaps of each rolling stand, wherein η.sub.0i=b.Math.exp(−a.Math.T.sub.i), in the formula, a,b are the dynamic viscosity parameters of lubricating oil under atmospheric pressure, and it can be obtained from a=0.05, b=2.5 that η.sub.0i={5.39,5.46,5.59,5.69,5.84};

[0144] S9.2, calculating the oil film thickness ξ.sub.i between the roll gaps of each rolling stand according to the following formula:

[00045]${\xi }_i=\frac{h_{0i}+h_{1i}}{2h_{0i}}.Math.k_c.Math.\frac{3\theta {\eta }_{0i}\left(v_{\mathrm{ri}}+v_{0i}\right)}{{\alpha }_i\left[1-e^{-\theta \left(K-\frac{T_{0i}}{h_{0i}.Math.B}\right)}\right]}-k_{rg}.Math.\left(1+K_{rs}\right).Math.{\mathrm{Ra}}_{\mathrm{ir}0}.Math.e^{-B_{\mathrm{Li}}{L}_i}$

[0145] wherein in the formula, k.sub.rg represents the coefficient of the strength of entrainment of lubricant by the longitudinal surface roughness of the work roll and the strip steel, k.sub.rg=1.183, and K.sub.rs represents the impression rate, that is, the ratio of transferring the surface roughness of the working roll to the strip, K.sub.rs=0.576, from which it can be obtained that: ξ.sub.i={0.784,0.963,2.101,2.043,1.326} um;

[0146] S9.3, calculating an emulsion flow rate comprehensive optimization objective function:

[00046]$\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array}\hspace{1em}$

[0147] in the formula, X={w.sub.i} is the optimization variable, λ=0.5 is the distribution coefficient, and thus F(X)=0.94;

[0148] S10, enabling w.sub.i.sup.y=w.sub.i={900,900,900,900,900}L/min if F(X)=0.94<F.sub.0=1×10.sup.10 is established, F.sub.0=F(X)=0.94, turning to step S11, wherein in the subsequent x calculation processes, the corresponding F(X) is obtained with the change of w.sub.i, and the x.sup.th F.sub.0 is the x−1.sup.th F(X). If the x.sup.th F(X) is smaller than the x−1.sup.th F(X), it is judged that F(X)<F.sub.0 is established and turn to step S11;

[0149] S11, determining whether the emulsion flow rate w.sub.i exceeds the feasible region range. If yes, turning to step S12; otherwise, turning to step S7; and

[0150] S12, outputting an optimal emulsion flow rate set value w.sub.i.sup.y={1022,1050,1255,1698,1102}L/min.

Embodiment 2

[0151] In order to further explain the application process of the related technology of the present application, the application process of an emulsion flow optimization method for a cold continuous rolling mill that aims to achieve vibration suppression is described by taking a 1420 cold continuous rolling mill in a cold rolling plant as an example.

[0152] An emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill includes the following steps:

[0153] S1, collecting device feature parameters of the cold continuous rolling mill, wherein the 1420 cold continuous rolling mill in a cold rolling plant has 5 rolling stands in total, and the device feature parameters mainly include: the radius R.sub.i{211,213,233,233,229} mm of a working roll of each rolling stand, the surface linear velocity ν.sub.ri={182,322,504,805,1153} m/min of a roll of each rolling stand, the original roughness Ra.sub.ir0={1.0,1.0,0.9,0.9,1.0} um of a working roll of each rolling stand, the roughness attenuation coefficient B.sub.L=0.015 of a working roll, the distance l=2750 mm between rolling stands, and the rolling kilometer L.sub.i={120,130,230,190,200} km after roll change of a working roll of each rolling stand, wherein i is 1, 2, . . . , n, and represents the ordinal number of rolling stands of the cold continuous rolling mill, and n=5 is the total number of rolling stands, the same below;

[0154] S2, collecting key rolling process parameters of a strip, wherein the key rolling process parameters mainly include: the inlet thickness h.sub.0i={2.1,1.15,0.65,0.45,0.3} mm of each rolling stand, the outlet thickness h.sub.1i={1.15,0.65,0.45,0.3,0.15} mm of each rolling stand, strip width B=955 mm, the inlet speed ν.sub.0i={115,193,346,555,852} m/min of each rolling stand, the outlet speed ν.sub.1i={191,344,556,849,1217} m/min of each rolling stand, the inlet temperature T.sub.1.sup.r=115° C., strip deformation resistance K.sub.i={370,410,490,590,660} MPa of each rolling stand, rolling pressure P.sub.i={12820,11330,10510,9630,8820} kN of each rolling stand, back tension T.sub.0i={73,148,210,205,232}MPa of each rolling stand, front tension T.sub.1i={147,212,206,231,60} MPa of each rolling stand, emulsion concentration influence coefficient k.sub.c=0.9, pressure-viscosity coefficient θ=0.036 of a lubricant, strip density ρ=7800 kg/m.sup.3, specific heat capacity S=0.49 kJ/(kg.Math.° C.) of a strip, emulsion concentration C=4.5%, emulsion temperature T.sub.c=59° C. and thermal-work equivalent J=1;

[0155] S3, defining process parameters involved in the process of emulsion flow optimization, wherein the process parameters mainly include that an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand is and the friction coefficient at this time is u.sub.i.sup.+, an under-lubrication film thickness critical value is and the friction coefficient at this time is u.sub.i.sup.−, the rolling reduction amount is Δh.sub.i=h.sub.0i−h.sub.1i, the rolling reduction rate is

[00047]${\mathrm{.Math.}}_i=\frac{\Delta h_i}{h_{0i}},$

[0156] the inlet temperature of each rolling stand is T.sub.i.sup.r, the distance l=2750 mm between the rolling stands is evenly divided into m=30 sections, and the temperature in the sections is represented by T.sub.i,j (wherein, 1≤j≤m), and T.sub.i.sup.r=T.sub.i−1,m, the over-lubrication judgment coefficient is A.sup.+, and the under-lubrication judgment coefficient is A.sup.−;

[0157] S4, setting the initial set value of an emulsion flow rate comprehensive optimization objective function of a cold continuous rolling mill that aims to achieve vibration suppression as F.sub.0=1.0×10.sup.10;

[0158] S5, calculating the bite angle α.sub.i of each rolling stand according to the rolling theory, wherein the calculation formula is

[00048]${\alpha }_i=\sqrt{\frac{\Delta h_i}{R_i^{\prime }}},$

[0159] from which it can be obtained that α.sub.i={0.0566,0.0431,0.0261,0.0227,0.0188};

[0160] S6, calculating the vibration determination index reference value ξ.sub.0i of each rolling stand;

[0161] S6.1, calculating the neutral angle γ.sub.i of each rolling stand, wherein the calculation formula is

[00049]${\gamma }_i=\frac{1}{2}\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}\left[1+\frac{1}{2u_i}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)\right];$

[0162] S6.2, calculating to obtain u.sub.i.sup.+={0.0251,0.0187,0.0135,0.0138,0.0193} according to the formula

[00050]$u_i^{+}=\frac{1}{2\left(2A^{+}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0163] from steps S5 and S6.1 assuming that when

[00051]$\frac{{\gamma }_i}{{\alpha }_i}=A^{+}=1,$

[0164] the roll gap is just in an over-lubrication state;

[0165] S6.3, calculating an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i (in the formula, a.sub.i is the liquid friction influence coefficient, a.sub.i=0.0128, b.sub.i is the dry friction influence coefficient, b.sub.i=0.1426, and B.sub.i is the friction coefficient attenuation index, B.sub.i=−2.4307), wherein the calculation formula is

[00052]${\xi }_i^{+}=\frac{1}{B_i}\ln \frac{u_i^{+}-a_i}{b_i},$

[0166] from which it can be obtained that: ξ.sub.i.sup.+={1.011,1.321,2.253,2.041,1.272} um;

[0167] S6.4, calculating to obtain u.sub.i.sup.−={0.1243,0.0936,0.0664,0.0685,0.0955} according to the formula

[00053]$u_i^{-}=\frac{1}{2\left(2A^{-}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0168] from steps S5 and S6.1 assuming that when

[00054]$\frac{{\gamma }_i}{{\alpha }_i}=A^{-}=0.6,$

[0169] the roll gap is just in an under-lubrication state;

[0170] S6.5, calculating an under-lubrication film thickness critical value of ξ.sub.i.sup.− each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i, wherein the calculation formula is

[00055]${\xi }_i^{-}=\frac{1}{B_i}\ln \frac{u_i^{-}-a_i}{b_i},$

[0171] from which it can be obtained that: ξ.sub.i.sup.−={0.101,0.236,0.411,0.389,0.223} um;

[0172] S6.6, calculating the vibration determination index reference value ξ.sub.0i, wherein

[00056]${\xi }_{0i}=\frac{{\xi }_i^{+}+{\xi }_i^{-}}{2},$

[0173] from which it can be obtained that: ξ.sub.0i={0.557,0.769,1.327,1.215,0.746};

[0174] S7, setting the emulsion flow rate of each rolling stand to be w.sub.i={900,900,900,900,900} L/min;

[0175] S8, calculating the strip outlet temperature T.sub.i of each rolling stand,

[0176] S8.1, calculating the outlet temperature T.sub.1 of the first rolling stand,

[00057]$T_1=T_1^r+\frac{1-\left({\mathrm{.Math.}}_1/4\right)}{1-\left({\mathrm{.Math.}}_1/2\right)}.Math.\frac{K_1\ln \left(\frac{1}{1-{\mathrm{.Math.}}_1}\right)}{\rho \mathrm{SJ}}=110+\frac{1-\left(0.43/4\right)}{1-\left(0.43/2\right)}.Math.\frac{360\ln \left(\frac{1}{1-0.43}\right)}{7.8.Math.0.47.Math.1}=175.81°C.$

[0177] S8.2, enabling i=1;

[0178] S8.3, calculating the temperature T.sub.1,1, of the first section of strip behind the outlet of the first rolling stand, i.e. T.sub.i,1=T.sub.i=175.81° C.;

[0179] S8.4, enabling j=2;

[0180] S8.5, showing the relationship between the temperature of the j.sup.th section and the temperature of the j−1.sup.th section by the following equation:

[00058]$T_{i,j}=-\frac{2k_0{w}_i^{0.264}\exp \left(9.45-0.1918C.\right)\times 1.163l}{v_{1i}{h}_{1i}\rho Sm}{T}_{i,j-1}^{-0.213}\left(T_{i,j-1}-T_c\right)+T_{i,j-1},$

[0181] wherein k.sub.0=1.0;

[0182] S8.6, determining whether the in-equation j<m is established: if yes, enabling j=j+1. and then turning to step S8.5; otherwise, turning to step S8.7;

[0183] S8.7, obtaining the temperature T.sub.1,30=105.41° C. of the m=30.sup.th section by iterative calculation finally;

[0184] S8.8, calculating the inlet temperature T.sub.2.sup.r of the second rolling stand: T.sub.2.sup.r=T.sub.1,m=105.41° C.;

[0185] S8.9, calculating the outlet temperature T.sub.2 of the second rolling stand

[00059]$T_2=T_2^r+\frac{1-\left({\mathrm{.Math.}}_2/4\right)}{1-\left({\mathrm{.Math.}}_2/2\right)}.Math.\frac{K_2\ln \left(\frac{1}{1-{\mathrm{.Math.}}_2}\right)}{\rho \mathrm{SJ}}=103.32+\frac{1-\left(0.45/4\right)}{1-\left(0.45/2\right)}.Math.\frac{400\ln \left(\frac{1}{1-0.45}\right)}{7800.Math.0.47.Math.1}=182.52^{\circ }C.;$

[0186] S8.10, determining whether the in-equation i<n is established: if yes, enabling i=i+1, and then turning to step S8.3; otherwise, turning to step S8.11;

[0187] S8.11, obtaining the outlet temperature T.sub.i=1175.86,179.36,189.77,196.65,207.541° C. of each rolling stand;

[0188] S9, calculating an emulsion flow rate comprehensive optimization objective function F(X);

[0189] S9.1, calculating the dynamic viscosity η.sub.0i of an emulsion between roll gaps of each rolling stand, wherein η.sub.0i=b.Math.exp(−a.Math.T.sub.i), in the formula, a,b are the dynamic viscosity parameters of lubricating oil under atmospheric pressure, and it can be obtained from a=0.15, b=3.0 that η.sub.0i={5.45,5.78,5.65,5.75,5.89};

[0190] S9.2, calculating the oil film thickness ξ.sub.i between the roll gaps of each rolling stand according to the following formula:

[00060]${\xi }_i=\frac{h_{0i}+h_{1i}}{2h_{0i}}.Math.k_c.Math.\frac{3\theta {\eta }_{0i}\left(v_{\mathrm{ri}}+v_{0i}\right)}{{\alpha }_i\left[1-e^{-\theta \left(K-\frac{T_{0i}}{h_{0i}.Math.B}\right)}\right]}-k_{rg}.Math.\left(1+K_{rs}\right).Math.{\mathrm{Ra}}_{\mathrm{ir}0}.Math.e^{-B_{\mathrm{Li}}.Math.L_i}$

[0191] wherein in the formula, k.sub.rg represents the coefficient of the strength of entrainment of lubricant by the longitudinal surface roughness of the work roll and the strip steel, k.sub.rg=1.196, and K.sub.rs represents the impression rate, that is, the ratio of transferring the surface roughness of the working roll to the strip, K.sub.rs=0.584, from which it can be obtained that: ξ.sub.i={0.795,0.967,2.132,2.056,1.337} um;

[0192] S9.3, calculating an emulsion flow rate comprehensive optimization objective function:

[00061]$\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array}\hspace{1em}$

[0193] in the formula, X={w.sub.i} is the optimization variable, λ=0.5 is the distribution coefficient, and thus F(X)=0.98;

[0194] S10, enabling w.sub.i.sup.y=w.sub.i={900,900,900,900,900} L 1 min if F(X)=0.98<F.sub.0=1×10.sup.10 is established, F.sub.0=F(X)=0.98, turning to step S11, wherein in the subsequent x calculation processes, the corresponding F(X) is obtained with the change of w.sub.i, and the x.sup.th F.sub.0 is the x−1.sup.th F(X). If the x.sup.th F(X) is smaller than the x−1.sup.th F(X), it is judged that F(X)<F.sub.0 is established and turn to step S11;

[0195] S11, determining whether the emulsion flow rate w.sub.i exceeds the feasible region range. If yes, turning to step S12; otherwise, turning to step S7; and

[0196] S12, outputting an optimal emulsion flow rate set value w.sub.i.sup.y={1029,1055,1261,1703,1109} L/min.

Embodiment 3

[0197] In order to further explain the application process of the related technology of the present application, the application process of an emulsion flow optimization method for a cold continuous rolling mill that aims to achieve vibration suppression is described by taking a 1220 cold continuous rolling mill in a cold rolling plant as an example.

[0198] An emulsion flow optimization method for suppressing vibration of a cold continuous rolling mill includes the following steps:

[0199] S1, collecting device feature parameters of the cold continuous rolling mill, wherein the 1220 cold continuous rolling mill in a cold rolling plant has 5 rolling stands in total, and the device feature parameters mainly include: the radius R.sub.i={208,210,227,226,225} mm of a working roll of each rolling stand, the surface linear velocity ν.sub.ri={176,317,495,789,1146} m/min of a roll of each rolling stand, the original roughness Ra.sub.ir0={0.9,0.9,0.7,0.7,0.8} um of a working roll of each rolling stand, the roughness attenuation coefficient B.sub.L=0.01 of a working roll, the distance l=2700 mm between rolling stands, and the rolling kilometer L.sub.i={152,102,215,165,70} km after roll change of a working roll of each rolling stand, wherein i is 1, 2, . . . , n, and represents the ordinal number of rolling stands of the cold continuous rolling mill, and n=5 is the total number of rolling stands, the same below;

[0200] S2, collecting key rolling process parameters of a strip, wherein the key rolling process parameters mainly include: the inlet thickness h.sub.0i={1.8,1.05,0.57,0.39,0.25} mm of each rolling stand, the outlet thickness h.sub.1i={1.05,0.57,0.36,0.22,0.13} mm of each rolling stand, strip width B=876 mm, the inlet speed ν.sub.0i={104,185,337,546,844} m/min of each rolling stand, the outlet speed ν.sub.1i={188,337,548,845,1201}m/min of each rolling stand, the inlet temperature T.sub.1.sup.r=110° C., strip deformation resistance K.sub.i={355,395,476,580,640} MPa of each rolling stand, rolling pressure P.sub.i={12900,11200,10400,9600,8900} kN of each rolling stand, back tension T.sub.0i={74,141,203,201,219} MPa of each rolling stand, front tension T.sub.1i{140,203,199,224,50} MPa of each rolling stand, emulsion concentration influence coefficient k.sub.c=0.8, pressure-viscosity coefficient θ=0.035 of a lubricant, strip density ρ=7800 kg/m.sup.3, specific heat capacity S=0.45 kJ/(kg.Math.° C.) of a strip, emulsion concentration C=3.7%, emulsion temperature T.sub.c=55° C. and thermal-work equivalent J=1;

[0201] S3, defining process parameters involved in the process of emulsion flow optimization, wherein the process parameters mainly include that an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand is and the friction coefficient at this time is u.sub.i.sup.+, an under-lubrication film thickness critical value ξ.sub.i.sup.− is and the friction coefficient at this time is u.sub.i.sup.−, the rolling reduction amount is Δh.sub.i=h.sub.0i−h.sub.1i, the rolling reduction rate is

[00062]${\mathrm{.Math.}}_i=\frac{\Delta h_i}{h_{0i}},$

[0202] the inlet temperature of each rolling stand is T.sub.i.sup.r, the distance l=2700 mm between the rolling stands is evenly divided into m=30 sections, and the temperature in the sections is represented by T.sub.i,j (wherein, 1≤j≤m), and T.sub.i.sup.r=T.sub.i−1,m, the over-lubrication judgment coefficient is A.sup.+, and the under-lubrication judgment coefficient is A.sup.−;

[0203] S4, setting the initial set value of an emulsion flow rate comprehensive optimization objective function of a cold continuous rolling mill that aims to achieve vibration suppression as F.sub.0=1.0×10.sup.10;

[0204] S5, calculating the bite angle α.sub.i of each rolling stand according to the rolling theory, wherein the calculation formula is

[00063]${\alpha }_i=\sqrt{\frac{\Delta h_i}{R_i^{\prime }}},$

[0205] from which it can be obtained that α.sub.i={0.0546,0.0406,0.0247,0.0220,0.0179};

[0206] S6, calculating the vibration determination index reference value ξ.sub.0i of each rolling stand;

[0207] S6.1, calculating the neutral angle γ.sub.i of each rolling stand, wherein the calculation formula is

[00064]${\gamma }_i=\frac{1}{2}\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}\left[1+\frac{1}{2u_i}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)\right];$

[0208] S6.2, calculating to obtain u.sub.i.sup.+={0.0242,0.0179,0.0127,0.0130,0.0185} according to the formula

[00065]$u_i^{+}=\frac{1}{2\left(2A^{+}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0209] from steps S5 and S6.1 assuming that when

[00066]$\frac{{\gamma }_i}{{\alpha }_i}=A^{+}=1,$

[0210] the roll gap is just in an over-lubrication state;

[0211] S6.3, calculating an over-lubrication film thickness critical value of ξ.sub.i.sup.+ each rolling stand according to the relationship formula between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i (in the formula, a.sub.i is the liquid friction influence coefficient, a.sub.i=0.0125, b.sub.i is the dry friction influence coefficient, b.sub.i=0.1414, and B.sub.i is the friction coefficient attenuation index, B.sub.i=−2.4280), wherein the calculation formula is

[00067]${\xi }_i^{+}=\frac{1}{B_i}\ln \frac{u_i^{+}-a_i}{b_i},$

[0212] from which it can be obtained that: ξ.sub.i.sup.−={1.001,1.289,2.232,2.037,1.268} um;

[0213] S6.4, calculating to obtain u.sub.i.sup.−={0.1241,0.0922,0.0610,0.0630,0.0935} according to the formula

[00068]$u_i^{-}\frac{1}{2\left(2A^{-}-1\right)}\left(\sqrt{\frac{\Delta h_i}{R_i^{\prime }}}+\frac{T_{i0}-T_{i1}}{P_i}\right)$

[0214] from steps S5 and S6.1 assuming that when

[00069]$\frac{{\gamma }_i}{{\alpha }_i}=A^{-}=0.6,$

[0215] the roll gap is just in an under-lubrication state;

[0216] S6.5, calculating an under-lubrication film thickness critical value of ξ.sub.i.sup.− each rolling stand according to the relationship between the friction coefficient and the oil film thickness, i.e. u.sub.i=a.sub.i+b.sub.i.Math.e.sup.B.sup.i.sup..Math.ξ.sup.i, wherein the calculation formula is

[00070]${\xi }_i^{-}=\frac{1}{B_i}\ln \frac{u_i^{-}-a_i}{b_i},$

[0217] from which it can be obtained that: ξ.sub.i.sup.−:={0.097,0.223,0.398,0.385,0.210} um;

[0218] S6.6, calculating the vibration determination index reference value ξ.sub.0i, wherein

[00071]${\xi }_{0i}=\frac{{\xi }_i^{+}+{\xi }_i^{-}}{2},$

[0219] from which it can be obtained that: ξ.sub.0i={0.548,0.762,1.321,1.207,0.736};

[0220] S7, setting the emulsion flow rate of each rolling stand to be w.sub.i={900,900,900,900,900} L/min;

[0221] S8, calculating the strip outlet temperature T.sub.i of each rolling stand,

[0222] S8.1, calculating the outlet temperature T.sub.1 of the first rolling stand,

[00072]$T_1=T_1^r+\frac{1-\left({\mathrm{.Math.}}_1/4\right)}{1-\left({\mathrm{.Math.}}_1/2\right)}.Math.\frac{K_1\ln \left(\frac{1}{1-{\mathrm{.Math.}}_1}\right)}{\rho \mathrm{SJ}}=110+\frac{1-\left(0.43/4\right)}{1-\left(0.43/2\right)}.Math.\frac{360\ln \left(\frac{1}{1-0.43}\right)}{7.8.Math.0.47.Math.1}=169.96°C.$

[0223] S8.2, enabling i=1;

[0224] S8.3, calculating the temperature T.sub.1,1, of the first section of strip behind the outlet of the first rolling stand, i.e. T.sub.i,1=T.sub.i=169.96° C.;

[0225] S8.4, enabling j=2;

[0226] S8.5, showing the relationship between the temperature of the j.sup.th section and the temperature of the j−1.sup.th section by the following equation:

[00073]$T_{i,j}=-\frac{2k_0{w}_i^{0.264}\exp \left(9.45-0.1918C.\right)\times 1.163l}{v_{1i}{h}_{1i}\rho Sm}{T}_{i,j-1}^{-0.213}\left(T_{i,j-1}-T_c\right)+T_{i,j-1},$

[0227] wherein k.sub.0=1.0;

[0228] S8.6, determining whether the in-equation j<m is established: if yes, enabling j=j+1. and then turning to step S8.5; otherwise, turning to step S8.7;

[0229] S8.7, obtaining the temperature T.sub.1,30=101.25° C. of the m=30.sup.th section by iterative calculation finally;

[0230] S8.8, calculating the inlet temperature T.sub.2.sup.r of the second rolling stand: T.sub.2.sup.r=T.sub.1,m=101.25° C.;

[0231] S8.9, calculating the outlet temperature T.sub.2 of the second rolling stand:

[00074]$T_2=T_2^r+\frac{1-\left({\mathrm{.Math.}}_2/4\right)}{1-\left({\mathrm{.Math.}}_2/2\right)}.Math.\frac{K_2\ln \left(\frac{1}{1-{\mathrm{.Math.}}_2}\right)}{\rho \mathrm{SJ}}=103.32+\frac{1-\left(0.45/4\right)}{1-\left(0.45/2\right)}.Math.\frac{400\ln \left(\frac{1}{1-0.45}\right)}{7800.Math.0.47.Math.1}=175.86°C.;$

[0232] S8.10, determining whether the in-equation i<n is established: if yes, enabling i=i+1, and then turning to step S8.3; otherwise, turning to step S8.11;

[0233] S8.11, obtaining the outlet temperature T.sub.i={177.96,172.78,184.59,191.77,203.33}° C. of each rolling stand;

[0234] S9, calculating an emulsion flow rate comprehensive optimization objective function F(X);

[0235] S9.1, calculating the dynamic viscosity η.sub.0i of an emulsion between roll gaps of each rolling stand, wherein η.sub.0i=b.Math.exp(−a.Math.T.sub.i), in the formula, a,b are the dynamic viscosity parameter of lubricating oil under atmospheric pressure, and it can be obtained from a=0.15, b=2.0 that η.sub.0i={5.45,5.02,5.98,5.45,5.76};

[0236] S9.2, calculating the oil film thickness ξ.sub.i between the roll gaps of each rolling stand according to the following formula:

[00075]${\xi }_i=\frac{h_{0i}+h_{1i}}{2h_{0i}}.Math.k_c.Math.\frac{3\theta {\eta }_{0i}\left(v_{\mathrm{ri}}+v_{0i}\right)}{{\alpha }_i\left[1-e^{-\theta \left(K-\frac{T_{0i}}{h_{0i}.Math.B}\right)}\right]}-k_{rg}.Math.\left(1+K_{rs}\right).Math.{\mathrm{Ra}}_{\mathrm{ir}0}.Math.e^{-B_{\mathrm{Li}}.Math.L_i}$

[0237] wherein in the formula, k.sub.rg represents the coefficient of the strength of entrainment of lubricant by the longitudinal surface roughness of the work roll and the strip steel, k.sub.rg=1.165, and K.sub.rs represents the impression rate, that is, the ratio of transferring the surface roughness of the working roll to the strip, k.sub.rs=0.566, from which it can be obtained that: ξ.sub.i={0.774,0.926,2.088,2.032,1.318} um;

[0238] S9.3, calculating an emulsion flow rate comprehensive optimization objective function:

[00076]$\{\begin{array}{c}F\left(X\right)=\frac{\lambda }{n}\underset{i=1}{\overset{n}{.Math.}}\sqrt{{\left({\xi }_i-{\xi }_{0i}\right)}^2}+\left(1-\lambda \right)\max .Math.{\xi }_i-{\xi }_{0i}.Math.\\ {\xi }_i^{-}<{\xi }_i<{\xi }_i^{+}\end{array}\hspace{1em}$

[0239] In the formula, X={w.sub.i} is the optimization variable, λ=0.5 is the distribution coefficient, and thus F(X)=0.91;

[0240] S10, enabling w.sub.i.sup.y=w.sub.i={900,900,900,900,900} L/min if F(X)=0.91<F.sub.0=1×10.sup.10 is established, F.sub.0=F(X)=0.91, turning to step S11, wherein in the subsequent x calculation processes, the corresponding F(X) is obtained with the change of w.sub.i, and the x.sup.th F.sub.0 is the x−1.sup.th F(X). If the x.sup.th F(X) is smaller than the x−1.sup.th F(X), it is judged that F(X)<F.sub.0 is established and turn to step S11;

[0241] S11, determining whether the emulsion flow rate w.sub.i exceeds the feasible region range. If yes, turning to step S12; otherwise, turning to step S7; and

[0242] S12, outputting an optimal emulsion flow rate set value w.sub.i.sup.y={1016,1040,1266,1681,1111} L/min.

[0243] The invention is applied to the five-machine-frame cold continuous rolling mills 1730, 1420 and 1220 in the cold rolling plant. According to the production experience of the cold rolling plant, the solution of the invention is feasible, and the effect is very obvious. The invention can be further applied to other cold continuous rolling mills, and the popularization prospect is relatively broad.

[0244] To sum up, the technical solution of the invention is adopted, and the emulsion flow optimization method for suppressing vibration of the cold continuous rolling mill fully combines the device and process features of the cold continuous rolling mill, and aiming at the vibration defect problem, starting from the comprehensive optimization setting of the emulsion flow rate of each rolling stand, the method changes the previous idea of constant emulsion flow control for each rolling stand of the cold continuous rolling mill, and obtains the optimal set value of the emulsion flow rate for each rolling stand that aims to achieve vibration suppression by optimization; and the method greatly reduces the incidence of rolling mill vibration defects, improves production efficiency and product quality, and brings greater economic benefits for enterprises; and achieves the treatment for rolling mill vibration defects, and improves the surface quality and rolling process stability of a finished strip of a cold continuous rolling mill.