CN101920265A - Method for optimizing roll shifting process of middle roll of six-roll cold mill - Google Patents

Abstract

The invention discloses a method for optimizing a roll shifting process of a middle roll of a six-roll cold mill in the production process of cold-rolled strip steel. The roll shifting position of the middle roll is set optimally in a fully continuous cold rolling flying gauge change process so as to reduce the frequent roll shifting, abrasion and the influence of axial force on equipment, such as a roller, a bearing and the like. When the roll shifting of the middle roll is carried out, a roll shifting speed model of the middle roll is established by performing theoretical analysis on a rolling load and the axial force under the condition of different roll shifting speeds, and the influence of the axial force is reduced during the roll shifting of the middle roll. Through the process and the controlling and optimizing method, the abrasion of the equipment, such as the roller, the bearing and the like can be reduced, and the production capacity of the six-roll cold mill is increased on the basis of improving quality control of a shape of the cold-rolled strip steel.

Description

Six-roll cold mill intermediate roll shifting process optimization method

Technical field

The present invention relates to the steel rolling field, be specially adapted to the control of six-high cluster mill cold rolled strip steel production and plate shape.

Background technology

Current, cold rolled strip steel production is extensive use of six-roll cold mill.The essential characteristic of six-roll cold mill is by the intermediate roll shifting mode, design by the continuously variable crown curve, perhaps improve the regulating power of cold-rolling mill, and then improve the strip shape quality of cold-strip steel plate shape control in the belt steel rolling process by reducing the harmful moment of flexure of roll shop building.

Things often has two property.The six-roll cold mill great advantage is to improve the cold-rolled strip steel shape control ability by intermediate roll shifting.But simultaneously, endless rollings continuously after the two volume welding before and after adopting during owing to belt steel rolling, during intermediate roll shifting, moving intermediate calender rolls by hydraulic cylinder is to carry out under very big rolling load condition.At this moment, roll is subjected to bigger wearing and tearing and responsive to axial force, will and cause harmful effect equipment life to strip surface quality.Therefore, the influence of axial force and wearing and tearing when how to reduce intermediate roll shifting is prerequisites of better bringing into play the control of six-roll cold mill belt plate shape.

In order to improve six-roll cold mill plate shape control effect, reducing axial force, roll wear etc. influences plant equipment safety and strip surface quality factor, is necessary to use duty to carry out analysis and optimization to the six-roll cold mill intermediate calender rolls.

Summary of the invention

The purpose of this invention is to provide a kind of six-roll cold mill intermediate roll shifting process optimization method, characteristics at six-roll cold mill cold rolled strip steel production and the control of plate shape, by to the suffered Analysis of axial force of intermediate roll shifting speed, mill speed, roll-force and intermediate roll shifting, adopt steel rolling process control technology, computer control modelling technique to determine in the full continuous cold rolling production process, the process conditions of six-roll cold mill intermediate roll shifting and the speed of intermediate roll shifting control model.Its main purpose is to reduce roll suffered axial force in the play process, reduces roll wear, improving on the cold-rolled strip steel shape quality base, improves the service life of equipment.

For achieving the above object, technical scheme of the present invention is described below:

In the full cold continuous rolling production process continuously, two winding steel weld the continuous rolling mode before and after adopting.Therefore, may there be certain difference in the width of front and back two winding steel, as shown in Figure 1.If front and back two winding steel width specifications have bigger variation, in order to guarantee six-roll cold mill plate shape control effect, need be according to the roll shifting amount of the modifications intermediate calender rolls of strip width, computation model is suc as formula 1.

S _i＝(L-B)/2-Δ-δ

In the actual production process, in most cases, the not too big variation of the width specifications of front and back winding steel.But because cold rolling production supplied materials width, and the difference of pickling line side cut amount, the width of winding steel has slight variations before and after can causing.According to normal control program, then need intermediate calender rolls to carry out the calculating of intermediate roll shifting amount again, and carry out play by intermediate roll shifting hydraulic cylinder promotion roll according to this less difference of front and back winding steel.

And in fact, if the variable quantity of front and back two winding steel width is less, the variation of the intermediate roll shifting position that through type 1 calculates is less, and then slave plate shape control effect angle analysis there is no need to carry out the actual play of high-frequency intermediate calender rolls.Because high-frequency intermediate calender rolls play can produce bigger wearing and tearing and axial force, breaker roll surface and bring adverse influence equipment life.

For this reason, determine that intermediate roll shifting process optimization condition is:

B ₁≠B ₂ (1)

When as shown in Figure 1, winding steel in front and back is by wide narrowing down: | S ₁-S ₂|≤50, and B ₁＞B ₂(2)

When as shown in Figure 2, winding steel in front and back is by narrow broadening: | S ₁-S ₂|≤30, and B ₁＜B ₂(3)

In the formula: S _iBe the traversing amount of intermediate calender rolls, the mm of unit; L is an intermediate calender rolls roll surface length, the mm of unit; B is a strip width, the mm of unit; Δ is the distance of strip edge portion apart from the intermediate calender rolls end, and Δ is the 25mm constant value; δ is an intermediate calender rolls chamfering width; B ₁Be last winding steel width; B ₂Be back one winding steel width; S ₁Intermediate roll shifting position during for last winding steel rolling; S ₂Intermediate roll shifting position during for back one winding steel rolling.

Intermediate roll shifting is only in front and back winding steel wide variety, and under the prerequisite of satisfy condition simultaneously (1), (2) and (3), carries out the intermediate calender rolls play by hydraulic cylinder, otherwise intermediate calender rolls play not.

If front and back winding steel width and intermediate roll shifting change when satisfying condition (1) (2) (3), hydraulic cylinder will promote intermediate calender rolls and carry out play.At this moment, intermediate calender rolls play speed need be determined.Calculate as can be known according to theory, intermediate calender rolls velocity magnitude and intermediate calender rolls suffered axial resistance in the play process has close getting in touch.Excessive roll shifting speed can produce very big axial force, and this damages equipment such as breaker roll and bearing.If roll shifting speed is too small, then the dynamic variable specification time can prolong, and in becoming the specification process, the plate shape control quality of band steel will be affected.Therefore, determine that rational intermediate roll shifting speed is all significant to belt plate shape quality and milling equipment.

Under the normal rolling mode, along with the increase of the traversing speed of intermediate calender rolls, traversing resistance can constantly increase, and in order not damage roll surface, except increasing the emulsion lubrication between roller, also needs rationally to determine the traversing speed of intermediate calender rolls.According to theory analysis as can be known, traversing resistance is subjected to draught pressure and moves roller speed ratio v _F/ v _RInfluence, therefore can determine traversing speed by the relation of analyzing between the three.Be illustrated in figure 3 as traversing resistance measurement data and calculated value under two groups of different speed ratios, when speed ratio was definite value, traversing resistance and roll-force were linear substantially, and along with the increase of speed ratio, the slope of both linear relationships also increases gradually.Fig. 4 is the relation of the roll-force calculated according to the traversing resistance expression formula of intermediate calender rolls traversing resistance and speed ratio when constant.Speed ratio hour, traversing resistance and speed ratio are approximated to linear relationship.

By Fig. 3, Fig. 4 and relevant traversing resistance theory analysis as can be known, when moving the roller speed ratio hour, traversing resistance and speed ratio are approximated to linear relationship, and traversing resistance is approximated to linear relationship with draught pressure, so can be with speed ratio v in the corresponding linear interval _F/ v _RSet the traversing speed of intermediate calender rolls as the linear function of roll-force, by numerical computations and to the equipment practical operation situation analysis determine the traversing rate pattern of intermediate calender rolls and be suitable for interval, as shown in Figure 5.

When roll gap was opened, roll gap pressure was less, and the traversing resistance of intermediate calender rolls is also less, and traversing speed can not considered the roll-force factor, only was made as the function of roll linear velocity, and regulated by ramp function according to the roll linear velocity.After wearing band, the traversing speed of intermediate calender rolls not only will be considered mill speed, also will consider the factor of roll-force.When roll-force is big, must reduce the traversing speed of intermediate calender rolls.

At speed ratio v _F/ v _RIn between the linear zone corresponding with traversing resistance, corresponding speed ratio v _F/ v _RBe respectively [v with the interval range of roll-force correspondence _F1/ v _R1, v _F2/ v _R2] and [P ₁, P ₂].In between this linear zone, traversing speed is set at:

$v_F=[\frac{v_{F2}/v_{R2}-v_{\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="H2009100119236E0000031.png"\; state="\{\{state\}\}">F</figure-callout>}1}/v_{R1}}{P_2-{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H2009100119236E0000031.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}\&CenterDot;(P-P_1)+\frac{v_{F1}}{v_{R1}}]\&CenterDot;v_R,({\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H2009100119236E0000031.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&le;P\&le;P_2)$

In the formula: v _F1/ v _R1And v _F2/ v _R2Be respectively 0.0005 and 0.00025, P ₁, P ₂Be respectively 2000KN and 10000KN.

According to the rolling mill practice and the device parameter of cold-rolling mill, normal rolling operation is in this linearity interval range substantially.Outside linear regional extent, traversing speed is set at the function of mill speed according to following formula:

$v_F=\left\{\begin{array}{cc}\frac{v_{F1}}{v_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="H2009100119236E0000031.png"\; state="\{\{state\}\}">R</figure-callout>}1}}\&CenterDot;v_R& (P\&le;P_1)\\ \frac{v_{F2}}{v_{R2}}\&CenterDot;v_R& (P\&GreaterEqual;P_2)\end{array}\right.$

When roll-force during less than 20KN, think that roll gap is in open mode, this moment, the traversing speed of intermediate calender rolls was set at:

v _F＝v _R/500 (P≤P ₀)

In the formula: P ₀Roll-force when opening for roll gap is worth and is 20KN.

Advantage of the present invention is: at the characteristics of six-roll cold mill cold rolled strip steel production and the control of plate shape, by to the suffered Analysis of axial force of intermediate roll shifting speed, mill speed, roll-force and intermediate roll shifting, adopt steel rolling process control technology, computer control modelling technique to determine in the full continuous cold rolling production process, the process conditions of six-roll cold mill intermediate roll shifting and the speed of intermediate roll shifting control model.Its main purpose is to reduce roll suffered axial force in the play process, reduces roll wear, improving on the cold-rolled strip steel shape quality base, improves the service life of equipment.

Description of drawings

Fig. 1 be cold continuous rolling dynamic variable specification strip width change by the wide schematic diagram that narrows down;

Fig. 2 be cold continuous rolling dynamic variable specification strip width change by the narrow schematic diagram that broadens;

Fig. 3 is the relation curve of traversing resistance and roll-force;

Fig. 4 is the relation curve of traversing resistance and speed ratio;

Fig. 5 is the traversing rate pattern curve of intermediate calender rolls.

The specific embodiment

The present invention will be further described below in conjunction with drawings and Examples.

The six-roll cold mill intermediate roll shifting model that obtains based on this patent is used for certain 1500 tandem mills production.Milling equipment parameter such as table 1:

Table 11 500mm cold-rolling mill device parameter

Embodiment 1 last winding steel width is 1020mm, and back one winding steel width is 1000mm.According to roll shifting modular form (1) as can be known, the intermediate roll shifting position is 220mm during last winding steel rolling, and the intermediate roll shifting position is 230mm during the one winding steel rolling of back.Determine intermediate calender rolls play not when winding steel in front and back becomes specification by intermediate roll shifting conditional (2).

Embodiment 2 last winding steel width are 1020, and back one winding steel width is 900mm.According to roll shifting modular form (1) as can be known, the intermediate roll shifting position is 220mm during last winding steel rolling, and the intermediate roll shifting position is 280mm during the one winding steel rolling of back.Determine intermediate calender rolls play when winding steel in front and back becomes specification by intermediate roll shifting conditional (2).

At this moment, if roll-force is 9000KN, mill speed is 15m/s, and can calculate intermediate roll shifting speed according to intermediate roll shifting speed calculating modular form (5) this moment is 4.2m/s.

At this moment, if roll-force is 12000KN, mill speed is 15m/s, and can calculate intermediate roll shifting speed according to intermediate roll shifting speed calculating modular form (6) this moment is 3.75m/s.

Claims (2)

1. six-roll cold mill intermediate roll shifting process optimization method is characterized in that, by setting up roll shifting condition and roll shifting rate pattern in the dynamic variable specification process, reduces the influence of roll suffered axial force in the play process;

Intermediate roll shifting is only in front and back winding steel wide variety, and under the prerequisite of satisfy condition simultaneously (1), (2) and (3), carries out the intermediate calender rolls play by hydraulic cylinder, otherwise intermediate calender rolls play not, the roll shifting conditional expression is as follows:

B ₁≠B ₂ (1)

| S ₁-S ₂|≤50, and B ₁＞B ₂(2)

| S ₁-S ₂|≤30, and B ₁＜B ₂(3)

S ₁, S ₂Calculate by following formula

S _i＝(L-B)/2-Δ-δ (4)

In the formula: S _iBe the traversing amount of intermediate calender rolls, the mm of unit; L is an intermediate calender rolls roll surface length, and B is a strip width, the mm of unit; Δ is the distance of strip edge portion apart from the intermediate calender rolls end, and Δ is the 25mm constant value; δ is an intermediate calender rolls chamfering width; B ₁Be last winding steel width; B ₂Be back one winding steel width; S ₁Intermediate roll shifting position during for last winding steel rolling; S ₂Intermediate roll shifting position during for back one winding steel rolling.

2. six-roll cold mill intermediate roll shifting process optimization method according to claim 1 is characterized in that, is satisfying under the six-roll cold mill intermediate roll shifting condition, sets up intermediate roll shifting speed control model;

In the cold-rolled process, carry out continuous rolling after the welding of front and back winding steel, in the traversing process of six-roll cold mill intermediate calender rolls, the traversing speed of intermediate calender rolls not only will be considered mill speed, also will consider the factor of roll-force; When roll-force is big, must reduce the traversing speed of intermediate calender rolls, otherwise roll can influence the life-span of roll owing to excessive axial force causes roll surface wear;

If the traversing speed of intermediate calender rolls is v _F, intermediate calender rolls rotational line speed is v _RAt v _F/ v _RIn between the linear zone corresponding with traversing resistance, corresponding speed ratio v _F/ v _RBe respectively [v with the interval range of roll-force correspondence _F1/ v _R1, v _F2/ v _R2] and [P ₁, P ₂]; In between this linear zone, traversing speed is set at:

$v_F=[\frac{v_{F2}/v_{R2}-v_{F1}/v_{R1}}{P_2-P_1}\&CenterDot;(P-P_1)+\frac{v_{F1}}{v_{R1}}]\&CenterDot;v_R,(P_1\&le;P\&le;P_2)---\left(5\right)$

In the formula: v _F1/ v _R1And v _F2/ v _R2Be respectively 0.0005 and 0.00025, P ₁, P ₂Be respectively 2000KN and 10000KN.

According to cold-rolling mill rolling mill practice and device parameter, normal rolling operation is in this linearity interval range substantially.Outside linear regional extent, traversing speed is set at the function of mill speed according to following formula:

$v_F=\left\{\begin{array}{cc}\frac{v_{F1}}{v_{R1}}\&CenterDot;v_R& (P\&le;P_1)\\ \frac{v_{F2}}{v_{R2}}\&CenterDot;v_R& (P\&GreaterEqual;P_2)\end{array}\right.---\left(6\right)$

When roll-force during less than 20KN, think that roll gap is in open mode, this moment, the traversing speed of intermediate calender rolls was set at:

v _F＝V _R/500 (P≤P ₀) (7)

In the formula: P ₀Roll-force when opening for roll gap is worth and is 20KN.

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