CN1179369A - Plate shape measuring and controlling method for plate strip rolling process - Google Patents

Abstract

A method for measuring and controlling plate shape during the rolling of plate or band includes such steps as calculating the rigidity coefficient m of plate based on really measured convexity heredity coefficient n and rigidity coefficient q reflecting the characteristics of rolled workpiece: m=q(1-n)/n to obtain a measuring and controlling model for plate during rolling; creating comprehercsive calculation model for convexity of finished plate for the rolling mills both with and without plate shape controller; and creating comprehensive calculation model in the increment manner in which the plate shape is controlled by thickness distribution.

Description

The plate shape measurement of plate strip rolling process and control method

The present invention relates to a kind of plate shape measurement and control method of plate strip rolling process.Plate shape comprises the cross sectional shape (is characteristic quantity with the strip crown) and the strip flatness of plate.Strip crown generally with center thickness with represent apart from the plate thickness difference at 25 millimeters places of limit portion; Glacing flatness has two kinds of method for expressing, and a kind of is angularity, represent with crest and wavelength ratio, another kind use along plate wide to the extension rate variance represent, the present invention with the back a kind of, its symbol is Δ ε.

Strip comprises steel plate band, copper coin band, aluminium sheet band and non-metal board band, for sake of convenience, is representative with the steel plate band.Because it is more and more stricter that the user requires strip cross sectional shape and glacing flatness, and factory wishes also that for improving lumber recovery the strip crown value reduces, but the also certain strip crown value of some product requirement.That therefore, how to realize strip crown and strip flatness freely controls the key problem that becomes rolling technique.Three during the last ten years, growing a lot aspect plate shape control theory and the equipment.Aspect theoretical, the methods such as beam on elastic foundation, spring beam, finite element that mainly contain have been obtained steel plate cross sectional shape and pressure distribution etc.Aspect equipment, at first be roller mechanism controls plate shape, the stairstepping support roller has appearred in the sixties, has eliminated harmful contact the between working roll and the support roller, has improved the roller effect; The HC six-high cluster mill has been invented by HIT, the CVC roll that continuously changes roll crown has been invented by German SMS company; The Mitsubishi heavy industry has been invented the PC milling train of two rollers intersections etc.These devices provide strong means for free control panel shape.The development of new equipment and the hand-in-glove of iron and steel factory, most representative is Japanese Nippon Steel, has made significant contribution for this reason, has solved the technology problem in the milling train practical applications such as PC, HC; For more effectively bringing into play the effect of these new equipments, realize that plate shape is freely controlled, set up plate shape control model, its mathematic(al) representation is: $C_{h_i}=(1-\mathrm{\η})C_i+{\mathrm{\η}}_i\frac{h_i}{H_i}{C}_{H_i}^F---\left(1\right)$ $C_{H_i}^F=C_{h_{i-1}}-H_{i-1}{\mathrm{\Δ\ϵ}}_{i-1}---\left(2\right)$ ${\mathrm{\Δ\ϵ}}_i=\mathrm{\ξ}(\frac{C_{h_i}}{h_i}-\frac{C_{H_i}^F}{H_i})---\left(3\right)$

In the formula: C _h-plate crown value;

-inlet vector strip crown value;

C-machined steel strip crown value, or claim evenly to cut lotus strip crown value;

H-exit plate one-tenth-value thickness 1/10;

H-access panel one-tenth-value thickness 1/10;

η-coefficient of heredity, or claim carry-over factor, expression is with access panel convexity C _HSend exit plate convexity C to _hRatio, promptly

(1-η)-press the shape ratio, represent the efficiency factor of mechanical convexity;

ξ-plate shape interference coefficient, the relation of reflection strip crown rate of change amount and strip flatness;

Δ ε-steel plate to extending rate variance, is represented the steel plate flatness value along wide;

I-frame or road sequence number.

Above formula has reflected the rule between strip crown, glacing flatness and the thickness of slab.But the correct value of η is relatively more difficult in practicality.Its reason η first is the binary function of the wide and thickness of slab of plate; Second be the double-point information that η has comprised rolled piece and milling train.In addition, when practical application, how to determine correctly that roll wear and the hot convexity in the mechanical strip crown value is also relatively more difficult, if online real-time estimation roll wear of energy and hot convex value are very necessary.

The objective of the invention is at deficiency of the prior art, provide a kind of plate shape measurement and control method of plate strip rolling process, coefficient of heredity η is resolved into the rolled piece stiffness coefficient q of reflection rolled piece characteristic and milling train shape stiffness Coefficient m two parts of reflection rolling mill characteristic; Utilize rolled piece stiffness coefficient q to calculate easily, calculate the method for m by q and actual measurement η; By q and m, the strip crown that draws plate strip rolling process is measured and the control model.

The objective of the invention is to be achieved through the following technical solutions.

For the η in (1) formula is separated, utilize coefficient of heredity η and press shape than the characteristics that coefficient (1-η) sum equals 1, define two formulas: $\frac{m}{m+q}=1-\mathrm{\η}---\left(4\right)$ $\frac{q}{m+q}=\mathrm{\η}---\left(5\right)$

(4), (5) formula satisfies (1) formula feature, (4), (5) formula substitution (1) formula are drawn: $C_{h_i}=\frac{m}{q_i+m}{C}_i+\frac{q_i}{q_i+m}\·\frac{h_i}{H_i}{C}_{H_i}^F---\left(5\right)$

(2) difference substitution (6) and (3) formula is obtained: $C_{h_i}=\frac{q_i}{q_i+m}\·\frac{h_i}{H_i}{C}_{h_{i=1}}-\frac{q_i}{q_i+m}\·\frac{h_i^2}{H_i}{\mathrm{\Δ\ϵ}}_{i-1}+\frac{m}{q_i+m}{C}_i---\left(7\right)$ ${\mathrm{\Δ\ϵ}}_i=\mathrm{\ξ}(\frac{C_{h_i}}{h_i}-\frac{C_{h_{i-1}}}{h_{i-1}}+\mathrm{\Δ}{\mathrm{\ϵ}}_{i-1})---\left(8\right)$

(7), (8) two formulas are the plate shape measurement and the control model of plate strip rolling process of the present invention.

Rolled piece stiffness coefficient q _iBe calculated as follows by actual measurement i passage (or frame) draught pressure P, steel plate width value B, drafts Δ h, reduction ratio r etc.: $q_i=\frac{P_i}{B\sqrt{{\mathrm{\Δh}}_i{R}_i^{\′}}\·r_i}---\left(9\right)$

In the formula: the r-reduction ratio;

The P-draught pressure;

B-steel plate width value;

Δ h-drafts;

R '-roll flattening radius;

I-frame or road sequence number.

q _iAlso can calculate with presetting the rules value.

As long as experiment draws coefficient of heredity η in advance, just can go out (10) formula by (4) or (5) formula conversion, calculate milling train shape stiffness Coefficient m. $m=\frac{q(1-\mathrm{\η})}{\mathrm{\η}}---\left(10\right)$

M is the intrinsic parameter of milling train.

So the plate shape measurement and the control method of plate strip rolling process involved in the present invention, use actual measurement plate strip rolling process strip crown coefficient of heredity η, stiffness coefficient q with reflection rolled piece characteristic, calculate strip-mill strip-shape stiffness coefficient m, thereby obtain the plate shape measurement and the control model of plate strip rolling process, strip-mill strip-shape stiffness coefficient m as the formula (10), q is obtained than reduction ratio by actual measurement unit draught pressure, shown in (9) formula.The mathematic(al) representation of the plate shape measurement of plate strip rolling process and control model is shown in (7) formula and (8) formula.

When being applied in the plate shape of above-mentioned plate strip rolling process control model and milling train shape stiffness Coefficient m on the tandem mill, at two class equipments, a class is the milling train (as CVC.PC, HC, powerful roller etc.) that complete mechanical strip crown control device is arranged; Another kind of is not have the milling train that changes the roll crown equipment.First kind milling train can realize that plate shape is freely controlled; The second class milling train can adopt the optimization rolling procedure of plate shape the best.

On strip-mill strip, can realize Δ ε with complete plate shape control device _i=0, only just plate shape control law can be described intactly with (7) formula.(7) formula of application is calculated by the road, can directly be obtained the production board convexity The COMPREHENSIVE CALCULATING model, its mathematic(al) representation is: $C_{h_n}=\frac{\underset{i=n}{\overset{1}{\mathrm{\Π}}}{q}_i}{\underset{i=n}{\overset{1}{\mathrm{\Π}}}(q_i+m)}\·\frac{h_n}{H_1}{C}_{h_o}+\underset{j=2}{\overset{n}{\mathrm{\Σ}}}\frac{\underset{i=n}{\overset{j}{\mathrm{\Π}}}{q}_i}{\underset{i=n}{\overset{j-1}{\mathrm{\Π}}}(q_i+m)}\·\frac{{\mathrm{mh}}_n}{H_j}{C}_{j-1}+\frac{m}{q_n+m}{C}_n---\left(11\right)$

In the formula: n-tandem rolling frame number;

J-frame or road sequence number;

-inlet slab convex value;

-production board convex value.(11) formula shows, inlet slab convex value

With each frame machinery strip crown C _iAll influence the production board convex value

It influences rule and successively decreases, and is more little from finished frame influence far away more.This formula can be used for the analysis of tandem rolling strip convexity system, and analytical expression has replaced complicated computer Simulation calculation, has provided very clear physical significance.Prior purposes is to realize the On-line Estimation of roll wear and hot convexity, realizes the monitoring of strip crown Self Adaptive Control and strip crown.

On the milling train that does not change the roll crown equipment, use the optimization rolling procedure that this invention can be calculated plate shape the best.The plate shape control model of describing with (7), (8) formula combines with the comprehensive deposit optimization rules setting computational methods that wait, and can obtain plate shape optimum optimization rolling procedure.This moment Δ ε _i≠ 0, obtain COMPREHENSIVE CALCULATING method with the incremental form of thickness of slab distribution control panel shape, its mathematic(al) representation is:

Coefficient in the matrix: ${\mathrm{\α}}_1=\frac{q_i}{(q_i+m)h_{i-1}}\·(2h_i{\mathrm{\Δ\ϵ}}_{i-1}-C_{h_{i-1}})+\frac{\mathrm{mA}}{m+q_i}\·Q_i$ ${\mathrm{\α}}_2=\frac{{\mathrm{\ξ}}_i}{h_i^2}$ More than various in: the A-roll-force causes the mechanical strip crown value of roll deformation;

The P-roll-force;

The resistance of deformation of K-rolled piece;

The longitudinal rigidity of M-milling train;

Q _i-plasticity coefficient of rolled piece,

The S-gap values between rollers.When the above-mentioned plate shape control of application on various reversible mills or tandem mill model, milling train shape stiffness Coefficient m is the inherent feature parameter of milling train, it only is subjected to the influence of steel plate width, dimension of roller changes ignores, in order to determine the shape stiffness Coefficient m of milling train, can once survey and obtain, promptly to four kinds of wide steel plates of different plates of this mill milling, as being example with the 2800mm heavy and medium plate mill, institute's rolled plate width is 1400～2500mm, can select the brassboard width value and be 1200,1600,2000, four kinds of 2400mm.Milling train has under the condition of on-line measurement thickness and strip crown, gathers each passage pressure, thickness, strip crown etc. in normal productive process, just can obtain the m value.If there is not the on-line measurement device, can arrange dedicated experiments, artificial off-line measurement.

The plate shape measurement of plate strip rolling process provided by the present invention and control method can overcome the deficiencies in the prior art, rolled piece stiffness coefficient q and the milling train shape stiffness Coefficient m that reflects rolling mill characteristic with reflection rolled piece characteristic, obtain accurately to measure and controlling the Mathematical Modeling of plate strip rolling process plate shape, be applied in very large range to control the finished product convex value in the production practices, and the ability of the variation of compensation roll wear and hot convexity is arranged.

Embodiment:

On φ 700/ φ 1500 * 2400mm four roller heavy and medium plate mills, rolling 16Mn steel plate, billet size 60 * 2000mm, finished size 12 * 2000mm is by setting

Deng coefficient, draw the optimization rules table 1 of two kinds of finish to gauge pressure.From the numerical value of table 1 as can be seen, pressure distribution can in very large range be controlled the finished product convex value, and the variation of enough abilities with compensation roll wear and hot convexity arranged.

Table 1. 16Mn 60 * 2000 → 12 * 2,000 two kind of optimization rules

Passage	????h(mm)	????P(10KN)		????h(mm)	????P(10KN)
						????1	????53.26	????888.8	????52.57	????975.4
????2	????37.89	????2375.9		????44.64	????1189.2
						????3	????26.20	????2404.8	????37.87	????1189.5
????4	????21.03	????1309.7		????29.85	????1651.6
						????5	????16.78	????1309.7	????23.22	????1651.6
????6	????14.30	????916.6		????17.93	????1635.1
						????7	????12.80	????652.0	????14.27	????1382.9
????8	????12.00	????449.0		????12.00	????1133

Claims (3)

1. the plate shape measurement of a plate strip rolling process and control method, use the stiffness coefficient q of actual measurement plate strip rolling process strip crown coefficient of heredity η and reflection rolled piece characteristic, calculate strip-mill strip-shape stiffness coefficient m, thereby obtain the plate shape measurement and the control model of plate strip rolling process, it is characterized in that the strip-mill strip-shape stiffness coefficient Wherein q is obtained than reduction ratio by actual measurement unit draught pressure, and the mathematic(al) representation of the plate shape measurement of plate strip rolling process and control model is: $C_{h_i}=\frac{q_i}{q_i+m}\·\frac{h_i}{H_i}{C}_{h_{i-1}}-\frac{q_i}{q_i+m}\·\frac{h_i^2}{H_i}\mathrm{\Δ}{\mathrm{\ϵ}}_{i-1}+\frac{m}{q_i+m}{C}_i$ $\mathrm{\Δ}{\mathrm{\ϵ}}_i=\mathrm{\ξ}(\frac{C_{h_i}}{h_i}-\frac{C_{h_{i-1}}}{h_{i-1}}+\mathrm{\Δ}{\mathrm{\ϵ}}_{i-1})$

In the formula: C _h-plate crown value;

C-machinery steel plate degree value;

H-exit plate one-tenth-value thickness 1/10;

H-access panel one-tenth-value thickness 1/10;

The stiffness coefficient of q-reflection rolled piece characteristic;

M-milling train shape stiffness coefficient;

η-strip crown coefficient of heredity, the expression ratio convexity that will enter the mouth transmits or entails the outlet steel plate;

(1-η)-press the shape ratio, represent the efficiency factor of mechanical strip crown;

ξ-plate shape interference coefficient, the relation of reflection strip crown rate of change amount and strip flatness;

Δ ε-steel plate to extending rate variance, is represented the steel plate glacing flatness along wide;

I-frame or road sequence number.

2. plate shape investigating method according to claim 1 is characterized in that can realizing Δ ε on the strip-mill strip that has plate shape control device _i=0, so directly obtain the production board convexity

The COMPREHENSIVE CALCULATING model, its mathematic(al) representation is: $C_{h_n}=\frac{\underset{i=n}{\overset{1}{\mathrm{\Π}}}{q}_i}{\underset{i=n}{\overset{1}{\mathrm{\Π}}}(q_i+m)}\·\frac{h_n}{H_1}{C}_{h_o}+\underset{j=2}{\overset{n}{\mathrm{\Σ}}}\frac{\underset{i=n}{\overset{j}{\mathrm{\Π}}}{q}_i}{\underset{i=n}{\overset{j-1}{\mathrm{\Π}}}(q_i+m)}\·\frac{m{h}_n}{H_j}{C}_{j-1}+\frac{m}{q_n+m}{C}_n$

In the formula: n-tandem rolling frame number;

J-frame or road sequence number;

-inlet slab convex value;

-production board convex value.

3. plate shape investigating method according to claim 1 is characterized in that on the strip-mill strip that does not have plate shape control device Δ ε _i≠ 0, obtain COMPREHENSIVE CALCULATING method with the incremental form of thickness of slab distribution control panel shape, its mathematic(al) representation is:

Coefficient in the matrix: ${\mathrm{\α}}_1=\frac{q_i}{(q_i+m)h_{i-1}}\·(2h_i\mathrm{\Δ}{\mathrm{\ϵ}}_{i-1}-C_{h_{i-1}})+\frac{\mathrm{mA}}{m+q_i}\·Q_i$ ${\mathrm{\α}}_2=\frac{{\mathrm{\ξ}}_i}{h_i^2}$

More than various in: the A-roll-force causes the mechanical strip crown value of roll deformation;

The P-roll-force;

The resistance of deformation of K-rolled piece;

The longitudinal rigidity of M-milling train;

Q _i-plasticity coefficient of rolled piece,

The S-gap values between rollers.