CN105772505A - Method for rolling cold-rolled variable-thickness plate - Google Patents

Abstract

The invention relates to a method for rolling a cold-rolled variable-thickness plate. The method for rolling the cold-rolled variable-thickness plate includes the steps that firstly, a variable-thickness rolling mode is adopted, and the positions where outlet bands are connected end to end at each outline cycle are all marked; and secondly, the marks are recognized before the bands are rolled into a roll gap of a rolling mill, and the locations of the bands in the roll gap of the rolling mill are determined according to the distance between a recognizing machine and the roll gap of the rolling mill and the rolling speed, wherein the recognizing machine (5) and a length measuring roller (6) are installed on the inlet side of the rolling mill; and a marking device (3) and a length measuring roller (14) are installed on the outlet side of the rolling mill. According to the rolling method, as the positions where the outlet bands are connected end to end at each outline cycle are marked in the first step, positioning for later cutting is facilitated, or as the marks are recognized before the bands are rolled into the roll gap in the second rolling step, the locations of the bands are determined, and accurate rolling is conducted.

Description

Cold rolling Varying Thickness Plates milling method

Technical field

The present invention relates to a kind of method producing cold rolling Varying-thickness sheet material, particularly relate to a kind of cold rolling Varying Thickness Plates milling method.

Background technology

For the target of automobile lightweight, current automobile industry is being promoted the use of a kind of by rolling the thickness continually varying band thickening plate obtained.Can by individual or the mode of rolling rolls this thickening plate, the mode efficiency of coil rolling is higher, but follow-up shearing is had positioning requirements.It is illustrated in figure 1 thickening rolling schematic diagram.For the ease of roll control, the exit thickness profile of setting is periodic.

When thickening rolling, it may appear that the reduction ratio of a passage cannot meet product demand or an excessive situation causing deformed steel strip of percentage pass reduction, so that carry out two passes.DE102005031461A1 describes a kind of preparation method: hot rolling raw material first carries out the first time rolling of uniform thickness, afterwards, carries out first time heat treatment；The coil of strip after having moved back fire is carried out the second time rolling of Varying-thickness again, afterwards, carries out second time heat treatment.CN101602065B describes another kind of preparation method: before rolling, it is judged that supplied materials be uniform thickness or the cycle thickening, it is seen then that front passage can also is that cycle thickening rolling except uniform thickness rolling.EP0937521A2 discloses the patent of continuous thickening plate aligning, control system according on supplied materials with for identify each cycle profile head and the tail index aperture trigger smoothing roll action, visible, after thickening rolling, mark is done by band by the end to end place in each profile cycle.

In DE102005031461A1, the reduction ratio of the second passes is 10～80%, and a reduction ratio in thin district is still bigger.In CN101602065B, the situation that supplied materials is uniform thickness is also similar with DE102005031461A1, has the problem that a reduction ratio in thin district is bigger；Supplied materials is cycle thickening situation, and when second time rolls, the thickness of strip recorded by entrance is judged, it is determined that the original position of rolling, if the first passage is rolled rear belt steel thickness and had indivedual disturbance, then it may happen that error in judgement.

Summary of the invention

It is an object of the invention to provide a kind of cold rolling Varying Thickness Plates milling method, the method adopts the thickening rolling mode end to end place in outlet band each profile cycle to stamp labelling by the first passage, so that location during follow-up shearing, or before the second passes enters roll gap, labelling is identified, so that it is determined that strip location accurately rolls.

In order to realize above-mentioned technical purpose, the present invention adopts the following technical scheme that

A kind of cold rolling Varying Thickness Plates milling method, the first passage adopts Varying-thickness rolling mode, and the end to end place in outlet band each profile cycle marks；Before the second passes feed mill roll gap, labelling is identified, according to the distance between identifier and mill roll-gap, mill speed, it is determined that the strip location at mill roll-gap place；Particularly as follows:

In inlet of rolling mill side, identifier, measuring roller are installed, at outlet side, marker, measuring roller are installed；

Described milling method concretely comprises the following steps:

First, the exit thickness profile of rolled strip is set, continuous thickening plate each profile cycle includes at least a thicker portion and a thinner part；

Second, adopt not in the uniform thickness operation of rolling in the first passage, outlet side measuring roller starts accumulative outlet band length, when length aggregate-value reaches the outlet strip profile Cycle Length rolling front setting, outlet side marker makes labelling on outlet band, meanwhile, length aggregate-value resets and restarts to add up；There is labelling at the end to end place in outlet band each profile cycle；

3rd, when carrying out the second passes, it is arranged in entrance side identifier the labelling on band is identified, when recognizing a new mark, showing that a new profile cycle is about to enter mill roll-gap, mill control system will start the measured value of accumulation entrance side measuring roller, and and distance between identifier and roll gap compare, determine when labelling enters roll gap, and then the position of roll is controlled.

A kind of cold rolling Varying Thickness Plates milling method, concretely comprises the following steps:

First, before rolling, it is determined that outlet strip profile setting value, supplied materials is the slab such as grade of H, and an exemplar comprises tri-uniform thickness sections of h1/h2/h1, and corresponding length is Len1/Len2/Len3, and having two length is the changeover portion of T1/T2；

Second, it is determined that the sharing of load of passage pressure, depress to h1, h2 from H, total reduction isPassage pressure distribution: the first passage depresses to h1 ', h2 ', corresponding reduction ratio isSecond passage depresses to h1, h2 again, and corresponding reduction ratio is

3rd, the reduction ratio selecting the first passage is 10～45%, and the reduction ratio of the second passage is 5～40%；

4th, according to constant-volume principle, calculate each segment length of outlet of the first passage:

1) the uniform thickness section of corresponding h1 thickness, length is Len1, Len3,

When the first passes, thickness is h1 ', and corresponding length is:

${\mathrm{Len}1}^{\′}=\frac{h1\×\mathrm{Len}1}{{h1}^{\′}}$

${\mathrm{Len}3}^{\′}=\frac{h1\×\mathrm{Len}3}{{h1}^{\′}}$

2) the uniform thickness section of corresponding h2 thickness, length is Len2,

When the first passes, thickness is h2 ', and corresponding length is:

${\mathrm{Len}2}^{\′}=\frac{h2\×\mathrm{Len}2}{{h2}^{\′}}$

3) changeover portion of corresponding h1 → h2, h2 → h1, length is T1, T2 respectively,

When the first passes, h1 ' → h2 ', the changeover portion of h2 ' → h1 ', corresponding length is:

${T1}^{\′}=\frac{(h1+h2)\×T1}{{h1}^{\′}+{h2}^{\′}}$

${T2}^{\′}=\frac{(h1+h2)\×T2}{{h1}^{\′}+{h2}^{\′}};$

5th, the first passes:

Before rolling, first profile setting value is inputted mill control system, one exemplar comprises three uniform thickness sections of h1 '/h2 '/h1 ', corresponding length is Len1 '/Len2 '/Len3 ', having two length is the changeover portion of T1 '/T2 ', therefore, an exemplar Cycle Length is L '=Len1 '+T1 '+Len2 '+T2 '+Len3 '；

Mill control system will set mill speed, front and back tension force, and calculate the roll-force corresponding by H Direct Rolling to h1 ', h2 ' and fixed value of roller slit；

When rolling, the outlet side marker measured value according to outlet side measuring roller, stamp a labelling every length L ' to band；

6th, the second passes:

The supplied materials of inlet of rolling mill is to be the band of mechanical periodicity with markd thickness,

Before rolling, first by entrance, outlet profile numerical value input mill control system, inlet profiles: uniform thickness section thickness h 1 '/h2 '/h1 ', uniform thickness segment length Len1 '/Len2 '/Len3 ', transition section length T1 '/T2 ', Cycle Length L '=Len1 '+T1 '+Len2 '+T2 '+Len3 '；Outlet profile: uniform thickness section thickness h 1/h2/h1, uniform thickness segment length Len1/Len2/Len3, transition section length T1/T2, Cycle Length L=Len1+T1+Len2+T2+Len3；

Mill control system will set mill speed, front and back tension force, and calculating is rolled down to h1, h2 ' by h1 ' and is rolled down to the setting values such as the roll-force corresponding to h2 and roll gap；

Labelling on band is identified by inlet of rolling mill side identifier, the mill control system measured value according to identifier with the distance of mill roll-gap, mill speed and entrance side measuring roller, calculating the strip location at mill roll-gap place, and determine rolling parameter, milling train rolls.

Installed before shearing the shears of line and identify device, identify that the labelling that thickening rolling outlet band is done by device is identified, control the action of shears according to the signal identified, it is achieved automatic shearing.

Described outlet side marker takes the mode of machinery, laser or color spray to carry out labelling.

First passage of the milling method of the cold rolling thickening plate of the present invention adopts thickening rolling mode, the end to end place in outlet band each profile cycle has stamped labelling, so that location during follow-up shearing, or before the second passes enters roll gap, labelling is identified, according to the distance between identifier and roll gap, mill speed, determine the strip location at roll gap place, accurately roll.

The milling method of the cold rolling thickening plate of the present invention is to carry out rolling Varying-thickness rolling to from hot rolling or cold rolling raw material.

Accompanying drawing explanation

Fig. 1 is thickening rolling schematic diagram；

Fig. 2 is that thickening rolling objective contour sets schematic diagram；

Fig. 3 is that schematic diagram (bouncing roller is placed in above band) arranged by thickening rolling milling train；

Fig. 4 is that schematic diagram (bouncing roller is placed in below band) arranged by thickening rolling milling train；

Fig. 5 is that shears layout schematic diagram is sheared in thickening rolling；

Fig. 6 exemplar scale diagrams；

Fig. 7 is the first passage outlet ribbon dimension schematic diagram；

Fig. 8 is the second passage inlet of rolling mill band schematic diagram.

In figure: 1 pressure cylinder, 2 rolling-mill housing, 3 squeeze rolls, 4 thickness measuring rollers, 5 identifiers, 6 measuring rollers, 7 jockey pulleys, 8 guide rollers, 9 bouncing rollers, 10 coiling machines, 11 squeeze rolls, 12 thickness measuring rollers, 13 markers, 14 measuring rollers, 15 jockey pulleys, 16 guide rollers, 17 bouncing rollers, 18 coiling machines, 19 bands, 20 roll gap；Wherein: label 3 to 10 is the parts of entrance side, label 11 to 18 is outlet side parts；21 shears, 22 identify device.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the invention will be further described.

A kind of cold rolling Varying Thickness Plates milling method, the first passage adopts Varying-thickness rolling mode, and the end to end place in outlet band each profile cycle marks；Before the second passes feed mill roll gap, labelling is identified, according to the distance between identifier and mill roll-gap, mill speed, it is determined that the strip location at mill roll-gap place, accurately rolls.

It is be provided with identifier 5 and measuring roller 6 on existing milling train basis in inlet of rolling mill side that the milling train of the present invention is arranged, is provided with marker 13, measuring roller 14 at outlet side, referring to Fig. 3 and Fig. 4.Mill control system controls this marking machine 13, every a rolling cycle, strip steel is carried out a labelling, and marker 13 can take the mode of machinery, laser or color spray to carry out labelling.When the purposes of this labelling has be deliver to follow-up shearing unit at two: one, for identifying that device 22 identifies, and control the action of shears 21, referring to Fig. 5；Two is if desired roll the second passage or multi-pass, identifies for inlet of rolling mill side evaluator 5, and then controls the position of roll.Mark mode according to marker 13 selects corresponding evaluator 5.Rolling-mill housing 2 entrance install evaluator 5 can to being with markd strip steel to be identified after the first passes, thus positioning and rolling.

nullThe layout of milling train: milling train is for being symmetrically arranged，Namely entrance side and outlet side are arranged symmetrically with，Milling train includes: pressure cylinder 1、Rolling-mill housing 2、Entrance side parts and outlet side parts，Pressure cylinder 1 drives rolling-mill housing 2 rolled strip place to be mill roll-gap 20，Entrance side parts include: squeeze roll 3、Thickness measuring roller 4、Identifier 5、Measuring roller 6、Jockey pulley 7、Guide roller 8、Bouncing roller 9、Coiling machine 10，Each entrance side parts are arranged in order from inside to outside centered by mill roll-gap 20，Outlet side parts are: squeeze roll 11、Thickness measuring roller 12、Marker 13、Measuring roller 14、Jockey pulley 15、Guide roller 16、Bouncing roller 17、Coiling machine 18，Each outlet side parts are arranged in order from inside to outside centered by mill roll-gap 20，Referring to Fig. 3 and Fig. 4，Fig. 3 show bouncing roller 9、17 are placed in above band、Guide roller 8、Schematic diagram arranged by 16 milling trains being placed in below band，Fig. 4 show bouncing roller 9、17 are placed in below band、Guide roller 8、Schematic diagram arranged by 16 milling trains being placed in above band，Two kinds of structures.Milling train is arranged as symmetrical, namely entrance side and outlet side are arranged symmetrically with (setting), and each parts one_to_one corresponding is arranged, and can realize the once rolling in a direction, or the multi-pass rolling in a direction, also allow for milling train and carry out " back and forth " multi-pass and roll.

A kind of cold rolling Varying Thickness Plates milling method concretely comprises the following steps:

First, the exit thickness profile of rolled strip 19 is set, continuous thickening plate each profile cycle includes at least a thicker portion and a thinner part；Simplest situation is only one of which thickness section and a light filling bar, and it sets profile and shows two complete profile cycles referring to Fig. 2, Fig. 2.The mode that employing cycle profile sets, is possible not only to periodic adjustment roll gap, is easy to control realization, it is also possible to makes follow-up aligning, shear regular following.

Second, adopt not in the uniform thickness operation of rolling in the first passage, outlet side measuring roller 14 starts accumulative outlet band 19 length, when length aggregate-value reaches the outlet strip profile Cycle Length rolling front setting, outlet side marker 13 makes labelling on outlet band 19, meanwhile, length aggregate-value resets and restarts to add up；There is labelling at the end to end place in outlet band each profile cycle；Mill control system carries out labelling for each exemplar by this way on outlet band, facilitates follow-up aligning, shearing technique.If carrying out the second passes, then it is easy to location.

If the reduction ratio of a passage cannot meet product demand or an excessive situation causing deformed steel strip of percentage pass reduction, then needing to carry out two passes, supplied materials during the second passes is not stack pile supplied materials, but not uniform thickness supplied materials.

3rd, when carrying out the second passes, it is arranged in entrance side identifier 5 labelling on band 19 is identified, when recognizing a new mark, showing that a new profile cycle is about to enter mill roll-gap 20, mill control system will start the measured value of accumulation entrance side measuring roller 6, and and distance between identifier 5 and roll gap 20 compare, determine when labelling enters roll gap 20, and then the position of roll is controlled.

Band after thickening rolling is sheared.Installed before shearing the shears 21 of line and identify device 22, identify that the labelling that thickening rolling outlet band is done by device 22 is identified, control the action of shears 21 according to the signal identified, it is achieved automatic shearing, referring to Fig. 5.

Embodiment:

Consulting Fig. 2 to need the band of rolling to set to roll rear profile, Fig. 2 is that thickening rolling objective contour sets schematic diagram, carries out Varying-thickness rolling in the milling train of Fig. 3 and Fig. 4.During first passage of rolling, milling train outlet side marker 13 stamps a labelling every a setting cycle on outlet band 19, and marker 13 can take the mode of machinery, laser or color spray to carry out labelling.When the purposes of this labelling has be deliver to follow-up shearing unit at two: one, for identifying that device 22 identifies, and control the action of shears 21, referring to Fig. 5；Two is if desired roll the second passage, identifies for inlet of rolling mill side evaluator 5, and then controls the position of roll.Mark mode according to marker 13 selects corresponding evaluator 5.

In the operation of rolling, the guide roller 8,16 shown in Fig. 3 and Fig. 4 ensure that strip steel and the cornerite surveyed between Zhang Yi are constant, it is not necessary to additionally considers the coil diameter impact on tension force.Bouncing roller 9,17 position shown in Fig. 3 and Fig. 4, it is ensured that stablizing of the operation of rolling.

Such as there is an exemplar, it is desirable to size is as shown in Figure 6.Supplied materials is the slab such as grade of H.

Rolling has two kinds of strategies: one is directly the supplied materials of H is rolled into target shape by a passage；Two is that supplied materials is rolled into target shape by point two passages.Introduce respectively below with reference to Fig. 3 and Fig. 4:

One, a passes

Before rolling, first outlet thickness of strip profile setting value being inputted mill control system, an exemplar comprises tri-uniform thickness sections of h1/h2/h1, and corresponding length is Len1/Len2/Len3, and having two length is the changeover portion of T1/T2.Therefore, an exemplar Cycle Length is L=Len1+T1+Len2+T2+Len3, referring to Fig. 6.

Mill control system will set mill speed, front and back tension force, and calculate by H Direct Rolling to the setting values such as the roll-force corresponding to h1, h2 and roll gap.

When rolling, mill control system will be controlled according to setting value, actual value, and bouncing roller 9,17 ensure that the stability of rolling, it is to avoid thickness change causes that speed, tension fluctuation are excessive；Outlet side marker 13 will stamp a labelling every length L to band.

Two, two passes are divided

First, before rolling, it is determined that outlet thickness of strip profile setting value, supplied materials is the slab such as grade of H, and an exemplar comprises tri-uniform thickness sections of h1/h2/h1, and corresponding length is Len1/Len2/Len3, and having two length is the changeover portion of T1/T2；As shown in Figure 6；

Second, it is determined that the sharing of load of passage pressure, depress to h1, h2 from H, total reduction isPassage pressure distribution: the first passage depresses to h1 ', h2 ', corresponding reduction ratio isSecond passage depresses to h1, h2 again, and corresponding reduction ratio is

3rd, the reduction ratio selecting the first passage is 10～45%, and the reduction ratio of the second passage is 5～40%；

4th, according to constant-volume principle, calculate each segment length of outlet of the first passage:

1) the uniform thickness section of corresponding h1 thickness, length is Len1, Len3,

When the first passes, thickness is h1 ', and corresponding length is:

${\mathrm{Len}1}^{\′}=\frac{h1\×\mathrm{Len}1}{{h1}^{\′}}$

${\mathrm{Len}3}^{\′}=\frac{h1\×\mathrm{Len}3}{{h1}^{\′}}$

2) the uniform thickness section of corresponding h2 thickness, length is Len2,

When the first passes, thickness is h2 ', and corresponding length is:

${\mathrm{Len}2}^{\′}=\frac{h1\×\mathrm{Len}2}{{h2}^{\′}}$

3) changeover portion of corresponding h1 → h2, h2 → h1, length is T1, T2 respectively,

When the first passes, h1 ' → h2 ', the changeover portion of h2 ' → h1 ', corresponding length is:

${T1}^{\′}=\frac{(h1+h2)\×T1}{{h1}^{\′}+{h2}^{\′}}$

${T2}^{\′}=\frac{(h1+h2)\×T2}{{h1}^{\′}+{h2}^{\′}};$

5th, the first passes:

Before rolling, first profile setting value is inputted mill control system, one exemplar comprises three uniform thickness sections of h1 '/h2 '/h1 ', corresponding length is Len1 '/Len2 '/Len3 ', having two length is the changeover portion of T1 '/T2 ', therefore, an exemplar Cycle Length is L '=Len1 '+T1 '+Len2 '+T2 '+Len3 ', referring to Fig. 7；

Mill control system will set mill speed, front and back tension force, and calculate the setting values such as the roll-force corresponding by H Direct Rolling to h1 ', h2 ' and roll gap；

When rolling, the outlet side marker 13 measured value according to outlet side measuring roller 14, stamp a labelling every length L ' to band 19；

6th, the second passes:

The supplied materials of inlet of rolling mill is to be the band of mechanical periodicity with markd thickness, referring to Fig. 8；

Before rolling, first by entrance, outlet profile numerical value input mill control system, inlet profiles: uniform thickness section thickness h 1 '/h2 '/h1 ', uniform thickness segment length Len1 '/Len2 '/Len3 ', transition section length T1 '/T2 ', Cycle Length L '=Len1 '+T1 '+Len2 '+T2 '+Len3 '；Outlet profile: uniform thickness section thickness h 1/h2/h1, uniform thickness segment length Len1/Len2/Len3, transition section length T1/T2, Cycle Length L=Len1+T1+Len2+T2+Len3；

Mill control system will set mill speed, front and back tension force, and calculating is rolled down to h1, h2 ' by h1 ' and is rolled down to the setting values such as the roll-force corresponding to h2 and roll gap；

Labelling on band 19 is identified by inlet of rolling mill side identifier 5, the mill control system measured value according to identifier 5 with the distance of mill roll-gap 20, mill speed and entrance side measuring roller 6, calculating the strip location at mill roll-gap 20 place, and determine rolling parameter, milling train rolls.

Concrete numerical example:

Supplied materials is the slab such as grade of H=2.5mm.Require that the finished size rolled out is:

Thickness: h1=2.0mm, h2=1.0mm

Length: Len1=250mm, T1=100mm, Len2=500mm, T2=100mm, Len3=250mm

Two kinds of rolling strategies introduced below:

One, only with a passes

Before rolling, first by above-mentioned profile setting value input control system, an exemplar Cycle Length is L=Len1+T1+Len2+T2+Len3=1200mm.

Mill control system will set mill speed, front and back tension force, and calculate the setting values such as the roll-force corresponding to 2.5mm Direct Rolling to 2.0,1.0mm and roll gap.

When rolling, control system will be controlled according to setting value, actual value, and bouncing roller 9,17 ensure that the stability of rolling, it is to avoid thickness change causes that speed, tension fluctuation are excessive.Outlet side marker 13 will stamp a labelling every 1200mm to band.

Two, two passes are divided

First, it is determined that the sharing of load of passage pressure, total reduction isPassage pressure distribution: the first passage depresses to 2.2,1.5mm (corresponding reduction ratio is 12%, 40%), the second passage depresses to 2.0 again, 1.0mm (corresponding reduction ratio is 9.1%, 33.3%).

According to constant-volume principle, calculate each segment length of outlet of the first passage:

1) corresponding finished product thickness is the uniform thickness section of 2.0mm, and length is 250mm,

When the first passes, exit thickness is 2.2mm, then corresponding length is:

$\frac{2.0\×250}{2.2}=227.27\mathrm{mm}$

2) corresponding finished product thickness is the uniform thickness section of 1.0mm, and length is 500mm,

When the first passes, exit thickness is 1.5mm, then corresponding length is:

$\frac{1.0\×500}{1.5}=333.33\mathrm{mm}$

3) changeover portion of corresponding 1.0 → 2.0mm or 2.0 → 1.0mm, length is 100mm,

When the first passes, be the changeover portion of 1.5 → 2.2mm, 2.2 → 1.5mm, then corresponding length is:

$\frac{(1.0+2.0)\×100}{1.5+2.2}=81.08\mathrm{mm}$

First passes:

Before rolling, first by profile setting value input control system, an exemplar comprises tri-uniform thickness sections of 2.2/1.5/2.2mm, and corresponding length is 227.27/333.33/227.27mm, and having two length is the changeover portion of 81.08mm.Therefore, an exemplar Cycle Length is 227.27+81.08+333.33+81.08+227.27=950.03mm.

Mill control system will set mill speed, front and back tension force, and calculate by 2.5mm Direct Rolling to the setting values such as the roll-force corresponding to 2.2mm, 1.5mm and roll gap.

When rolling, outlet side marker 13, by the measured value according to outlet side measuring roller 14, marks to band 19 every 950.03mm.

Second passes:

Before rolling, first by entrance, outlet profile input mill control system,

Inlet profiles: uniform thickness section thickness 2.2/1.5/2.2mm,

Uniform thickness segment length 227.27/333.33/227.27mm,

Transition section length 81.08/81.08mm,

Cycle Length 227.27+81.08+333.33+81.08+227.27=950.03mm；

Outlet profile: uniform thickness section thickness 2.0/1.0/2.0mm,

Uniform thickness segment length 250/500/250mm,

Transition section length 100/100mm,

Cycle Length 250+100+500+100+250=1200mm；

Mill control system will set mill speed, front and back tension force, and calculating is rolled down to 2.0mm, 1.5mm by 2.2mm and is rolled down to the setting values such as the roll-force corresponding to 1.0mm and roll gap.

Labelling on band 19 will be identified by inlet of rolling mill side identifier 5, the mill control system measured value according to identifier 5 with the distance of mill roll-gap 20, mill speed and entrance measuring roller 6, calculates the strip location at roll gap 20 place, and determines rolling parameter.

In the manner described above, it is possible to rolling obtains target exemplar.

These are only presently preferred embodiments of the present invention, be not intended to limit protection scope of the present invention, therefore, all make within the spirit and principles in the present invention any amendment, equivalent replacement, improvement etc., should be included within protection scope of the present invention.

Claims (4)

1. a cold rolling Varying Thickness Plates milling method, is characterized in that:

First passage adopts Varying-thickness rolling mode, and the end to end place in outlet band each profile cycle marks；Before the second passes feed mill roll gap, labelling is identified, according to the distance between identifier and mill roll-gap, mill speed, it is determined that the strip location at mill roll-gap place；Particularly as follows:

Identifier (5), measuring roller (6) are installed in inlet of rolling mill side, at outlet side, marker (13), measuring roller (14) are installed；

Described milling method concretely comprises the following steps:

First, the exit thickness profile of rolled strip (19) is set, continuous thickening plate each profile cycle includes at least a thicker portion and a thinner part；

Second, adopt not in the uniform thickness operation of rolling in the first passage, outlet side measuring roller (14) starts accumulative outlet band length, when length aggregate-value reaches the outlet strip profile Cycle Length rolling front setting, outlet side marker (13) makes labelling on outlet band, meanwhile, length aggregate-value resets and restarts to add up；There is labelling at the end to end place in outlet band each profile cycle；

3rd, when carrying out the second passes, it is arranged in entrance side identifier (5) labelling on band (19) is identified, when recognizing a new mark, show that a new profile cycle is about to enter mill roll-gap (20), mill control system will start the measured value of accumulation entrance side measuring roller (6), and and identifier (5) and roll gap (20) between distance compare, determine when labelling enters roll gap, and then the position of roll is controlled.

2. cold rolling Varying Thickness Plates milling method according to claim 1, is characterized in that:

First, before rolling, it is determined that outlet strip profile setting value, supplied materials is the slab such as grade of H, and an exemplar comprises tri-uniform thickness sections of h1/h2/h1, and corresponding length is Len1/Len2/Len3, and having two length is the changeover portion of T1/T2；

Second, it is determined that the sharing of load of passage pressure, depress to h1, h2 from H, total reduction isPassage pressure distribution: the first passage depresses to h1 ', h2 ', corresponding reduction ratio isSecond passage depresses to h1, h2 again, and corresponding reduction ratio is

3rd, the reduction ratio selecting the first passage is 10～45%, and the reduction ratio of the second passage is 5～40%；

4th, according to constant-volume principle, calculate each segment length of outlet of the first passage:

1) the uniform thickness section of corresponding h1 thickness, length is Len1, Len3,

When the first passes, thickness is h1 ', and corresponding length is:

${\mathrm{Len}1}^{\′}=\frac{h1\×\mathrm{Len}1}{{h1}^{\′}}$

${\mathrm{Len}3}^{\′}=\frac{h1\×\mathrm{Len}3}{{h1}^{\′}}$

2) the uniform thickness section of corresponding h2 thickness, length is Len2,

When the first passes, thickness is h2 ', and corresponding length is:

${\mathrm{Len}2}^{\′}=\frac{h2\×\mathrm{Len}2}{{h2}^{\′}}$

3) changeover portion of corresponding h1 → h2, h2 → h1, length is T1, T2 respectively,

When the first passes, h1 ' → h2 ', the changeover portion of h2 ' → h1 ', corresponding length is:

${T1}^{\′}=\frac{(h1+h2)\×T1}{{h1}^{\′}+{h2}^{\′}}$

${T2}^{\′}=\frac{(h1+h2)\×T2}{{h1}^{\′}+{h2}^{\′}};$

5th, the first passes:

Before rolling, first profile setting value is inputted mill control system, one exemplar comprises three uniform thickness sections of h1 '/h2 '/h1 ', corresponding length is Len1 '/Len2 '/Len3 ', having two length is the changeover portion of T1 '/T2 ', therefore, an exemplar Cycle Length is L '=Len1 '+T1 '+Len2 '+T2 '+Len3 '；

Mill control system will set mill speed, front and back tension force, and calculate the setting values such as the roll-force corresponding by H Direct Rolling to h1 ', h2 ' and roll gap；

When rolling, the outlet side marker (13) measured value according to outlet side measuring roller (14), stamp a labelling every length L ' to band；

6th, the second passes:

The supplied materials of inlet of rolling mill is to be the band of mechanical periodicity with markd thickness,

Before rolling, first by entrance, outlet profile numerical value input mill control system, inlet profiles: uniform thickness section thickness h 1 '/h2 '/h1 ', uniform thickness segment length Len1 '/Len2 '/Len3 ', transition section length T1 '/T2 ', Cycle Length L '=Len1 '+T1 '+Len2 '+T2 '+Len3 '；Outlet profile: uniform thickness section thickness h 1/h2/h1, uniform thickness segment length Len1/Len2/Len3, transition section length T1/T2, Cycle Length L=Len1+T1+Len2+T2+Len3；

Mill control system will set mill speed, front and back tension force, and calculating is rolled down to h1, h2 ' by h1 ' and is rolled down to the roll-force corresponding to h2 and fixed value of roller slit；

Labelling on band (19) is identified by inlet of rolling mill side identifier (5), the mill control system measured value according to identifier (5) with the distance of mill roll-gap (20), mill speed and entrance side measuring roller (6), calculate the strip location at mill roll-gap (20) place, and determine rolling parameter, milling train rolls.

3. cold rolling Varying Thickness Plates milling method according to claim 1 and 2, it is characterized in that: installed before shearing the shears (21) of line and identify device (22), identify that the labelling that thickening rolling outlet band (19) is done by device (22) is identified, the action of shears (21) is controlled, it is achieved automatic shearing according to the signal identified.

4. cold rolling Varying Thickness Plates milling method according to claim 1 and 2, is characterized in that: described outlet side marker (13) takes the mode of machinery, laser or color spray to carry out labelling.