CN113290052A

CN113290052A - Rolling method of wide metal strip foil

Info

Publication number: CN113290052A
Application number: CN202110411543.2A
Authority: CN
Inventors: 刘洪勤; 马力; 徐继玲; 李毅
Original assignee: Anhui Jinchi New Material Co ltd; Shanghai Wuxing Copper Co ltd
Current assignee: Anhui Jinchi New Material Co ltd; Shanghai Wuxing Copper Co ltd
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-08-24
Anticipated expiration: 2041-04-16
Also published as: CN113290052B; WO2022217717A1

Abstract

A rolling method of wide metal strip foil uses rolling mills with working rolls with different diameters, wherein the roll diameter of one working roll of the rolling mill is larger than that of the other working roll; during rolling, the linear velocities of the roll surfaces of the two working rolls are the same, the metal strip foil is coated on the roll surface of a certain working roll at the inlet side or the outlet side of a roll gap formed by the two working rolls to form a coating arc, and the tension is uniformly distributed on the cross section of the coating arc through the back support of the working rolls on the metal strip foil. The invention rolls the strip foil by adopting the rolling mill with the working rolls with different diameters, which is not only beneficial to thinning the strip foil, but also beneficial to obtaining better plate shape. In addition, the invention enables the strip foil to form a coating arc on the working roll, and the back support of the working roll to the strip foil enables the front tension to be uniformly distributed on the cross section of the coating arc at the inlet side, thereby realizing the uniform rolling of the strip foil, breaking through the bottleneck restricting the strip foil to develop in the direction of wider, thinner and more ideal plate shape, and solving the technical problem in the industry.

Description

Rolling method of wide metal strip foil

Technical Field

The invention relates to the technical field of rolling, in particular to a rolling method of high-precision wide-width metal strips and foils, which is used for obtaining good plate shapes.

Background

With the advance of the scientific and technological industry, the market demand for high-precision wide-width thin strips and foils (hereinafter referred to as "strips and foils") is more and more urgent. In the current technical background, the rolling technology of wide and thick strips is basically mature, but the technical bottleneck is shown in the aspect of the rolling technology of high-precision wide and thinner strip foils, and breakthrough is urgently needed. For thicker strips, even if the strip shape defects exist after rolling, the strip shape can be finished and corrected by withdrawal straightening or other flattening means, and for thinner strip foils, especially extremely thin foils, the original rolled strip shape is the final strip shape of the product due to the lack of subsequent strip shape correction means. Particularly, for the strip foil with large deformation resistance such as copper, copper alloy, stainless steel and the like, the strip foil is restricted by the plate shape control capability of the prior rolling technology, and the stable high-quality production is difficult to realize. According to known information, the minimum rolling thickness of 0.006mm and the maximum width of 650mm can be achieved by mass production of pure copper foil, the minimum rolling thickness of 0.02mm and the maximum width of 600mm can be achieved by mass production of stainless steel foil, the rolled plate shape is not good, and if the width is increased continuously, the plate shape becomes worse.

The three basic conditions for stable rolling of the rolling mill are the roller system precision, the lubrication condition and the tension precision respectively. For rolling of an extremely thin strip foil, the reduction effect of the reduction amount is weakened, and the thickness reduction of the strip foil is realized by basically depending on the flattening rebound amount, the rolling speed and the larger unit tension of the working roll. The tension selected for the rolling of thicker strip material is typically no more than 16% of the yield strength of the strip material, so that the tension is not significant in the thinning of the strip material, the main effect of which is to establish a stable rolling regime. The rolling of the band foil with extremely thin thickness has great difference, and in order to fully utilize the thinning effect of the tension on the band foil, the unit tension is adopted to even reach 60 percent of the yield strength of the material. Since a large tension has a large effect on the thinning of the strip foil and naturally also on the rolled plate shape, the effect of the tension on the plate shape is mainly manifested as the uniformity of the distribution of the tension over the cross section of the strip foil.

As shown in fig. 1, the tension per unit width is ideally uniform and uniform in the cross section of the tape foil (including the side portions), but this is not the case in actual production. The actual tension distribution is shown in fig. 2, the distribution of the tension on the cross section of the strip foil is not uniform, the tension values at the two edges of the strip foil are the maximum, the tension value at the middle part is smaller, Δ T in the figure is the difference between the maximum value and the minimum value of the tension distribution along the width B direction of the strip foil, and the ratio Δ T/B can be referred to as the tension non-uniformity. There are many factors that cause tension non-uniformity in the cross-section of the tape foil, one from material composition, texture and annealing non-uniformity, which are random; another type of factor comes from rolling conditions, which are regularly found, such as the phenomenon of sudden edge thickness reduction of the strip foil during multiple ironing, which is described in the paper "three-dimensional analysis of cold-rolled strip deformation", which uses finite element method simulation to calculate the plate roll-off and cross-flow as a function of the strip edge distance, see steel rolling, third 1999. According to the roll pressure formula:

it is known that the fluctuations in zone thickness are accompanied by a lateral flow of the metal material (macroscopically manifested as a plate-shaped anomaly), which leads to fluctuations in the rolling force P1 in the zone, and fluctuations in the rolling force P1 lead to fluctuations in the tension S1 in the zone. The tension S1 fluctuation in the area, in turn, leads to fluctuation in the rolling force P1, and fluctuation in the rolling force P1 affects the lateral flow of the metal material, which is causal. This indicates that the tension applied to the cross-section of the strip foil during rolling is not uniform and that this tension non-uniformity is prevalent.

In the rolling process, the influence of front tension and rear tension on the strip shape is greatly influenced, and is recorded in a paper ' influence of tension on deformation of a cold-rolled strip ', and the paper discusses in detail through a three-dimensional simulation system that the transverse flow of metal is limited by increasing front and rear tension, so that the thickness deformation of the strip can be increased, the section thickness is more uniform, and the influence is detailed in the fourth stage of 35 volumes of steel '. Whereas for a strip foil increasing the front and back tension has a greater influence on the shape of the strip foil. The tension of the strip foil is not uniform in unit width, the deformation resistance, the roll gap and the material thickness of local rolling are not uniform, and finally, the rolled plate shape has defects (including potential defects), such as waves and wrinkles which often occur in the rolling process. More seriously, the severe tension changes in the two edge regions cause the foil to split at both edges and, once the split occurs, it rapidly stretches laterally, thereby causing the foil to break. The wider the strip foil is, the greater the tension unevenness is, the more difficult the strip shape is to control, which is a technical bottleneck restricting the strip foil to develop towards a wider, thinner and more ideal strip shape direction at present, and is also a technical problem difficult to solve in the industry for a long time, and how to make the tension uniformly distributed on the cross section of the strip foil is a key for solving the problem.

As shown in FIG. 3, the arrangement is a typical arrangement mode of the current foil rolling, and the foil 5 horizontally enters a roll gap along a rolling center line 6 after passing through a lifting roll 4 and a flattening roll 3 and is stretched in advance at home or abroad. As can be seen from fig. 3, before the band foil 5 enters the roll gap, the band foil located between the lower working roll 2 and the spreader roll 3 is always in a suspended and tightened state, so that the problem of uneven distribution of tension on the cross section of the band foil is solved, and the success or failure of the high-precision wide-width band foil rolling is directly influenced. According to the national standard, the error requirement of the level height of the rolling central line 6 is within 0.05mm/m, and the requirement of the level height is regulated because the stability of the neutral plane of the strip is ensured so as to realize the uniformity of the mechanical property of the strip. However, the method is difficult to achieve in actual production, the neutral surface of the strip material can be deviated to one side by factors such as shaking of the lifting roller under the action of the oil cylinder, roll diameter errors of the flattening roller and the working roller, and suspension of the strip material, and the deviation phenomenon is particularly serious for the thin strip foil, and a better solution is not provided at present.

Furthermore, as shown in fig. 4, both the upper work roll 1 and the lower work roll 2 of the rolling mill are of equal diameter design, both domestic and foreign, from the two-high rolling mill to the twenty-high rolling mill. Such a design facilitates maintenance and exchange of the work rolls, and the drive structure thereof is thus simplified for the rolling mill. The size of the work roll diameter is influential to the rolling of the strip. It is known that the smaller the diameter of the working roll, the more advantageous the thinning of the band foil 5, but this also presents problems: in fig. 4, the left work roll has a small diameter and a small rigidity, and has a large biting angle with respect to the strip foil 5, and a large lateral component force of the rolling force, and therefore has a large lateral bending tendency. In addition, the length of the bite arc of the left working roll to the band foil 5 is not favorable for the uniform introduction of the lubricating medium into the roll gap, and the uneven oil film thickness in the rolling arc area is caused. These factors result in a large fluctuation of the arc length of the rolling arc surface in the width direction of the strip foil, eventually causing a defect in the rolled sheet shape. Under the same conditions, the right work roll has a large diameter and a large rigidity, has a small biting angle with respect to the strip foil 5, and has a small lateral component force of the rolling force, and therefore has a small lateral bending tendency. In addition, the right working roll has longer bite arc length to the band foil 5, which is beneficial to the uniform introduction of the lubricating medium into the roll gap and enables the thickness of the oil film in the calendering arc area to be more uniform. These factors are all beneficial to reducing the arc length fluctuation of the rolling arc surface along the width direction of the strip foil, thereby obtaining better rolling shape.

In conclusion, the small-diameter working roll is beneficial to rolling and is limited in that the rolled plate shape is difficult to control, so that the rolled width is not suitable to be too large; the large-diameter working roll is beneficial to controlling the shape of a rolled plate, is suitable for rolling width, but is not suitable for rolling thinness. For wide-width strip foil with thickness less than 0.3mm, the diameter of the working roll must be small enough (usually 25-50mm in diameter) to obtain a large reduction amount, and the shape of the strip at this time is very difficult to control, which is also the bottleneck restricting the rolling of high-precision wide-width strip foil.

Disclosure of Invention

In order to overcome the defects in the background art, the invention discloses a rolling method of a wide metal strip foil, which aims to:

1. the tension is uniformly distributed on the cross section of the strip foil, and the metal strip foil is rolled uniformly;

2. the technical problem in the background technology is overcome, the technical bottleneck is broken, and the strip foil is rolled in a wide range and high precision.

In order to achieve the purpose, the invention adopts the following technical scheme:

a rolling method of wide metal strip foil uses rolling mills with working rolls with different diameters, wherein the roll diameter of one working roll of the rolling mill is larger than that of the other working roll; during rolling, the linear velocities of the roll surfaces of the two working rolls are the same, the metal strip foil is coated on the roll surface of a certain working roll at the inlet side or the outlet side of a roll gap formed by the two working rolls to form a coating arc, and the tension is uniformly distributed on the cross section of the coating arc through the back support of the working rolls on the metal strip foil.

The technical scheme is further improved, and the metal strip foil is coated on the surface of the working roller with the larger roller diameter to form a coating arc.

According to the technical scheme, the wrapping arc is obtained by changing the angle of the metal strip foil entering into the roller gap or flowing out of the roller gap.

The technical scheme is further improved, the coating angle of the coating arc is alpha, and alpha is more than 0 degree and less than or equal to 90 degrees.

The technical scheme is further improved, and metal strip foils are coated on the roll surfaces of the same or different working rolls at the inlet side and the outlet side of a roll gap to form an inlet side coating arc and an outlet side coating arc.

The technical scheme is further improved, and the metal strip foil is coated on the surface of the working roller with the larger roller diameter.

According to the technical scheme, the inlet side wrapping arc is obtained by changing the angle of the metal strip foil entering the roller gap, and the outlet side wrapping arc is obtained by changing the angle of the metal strip foil flowing out of the roller gap.

The technical scheme is further improved, and the diameter of the working roll with larger roll diameter is 1.5-5 times that of the working roll with smaller roll diameter.

The technical scheme is further improved, before the next rolling, the metal strip foil is turned over and then enters a rolling mill for rolling.

Further improves the technical scheme that the total rolling pass of the metal strip foil is even number of times.

Due to the adoption of the technical scheme, compared with the background technology, the invention has the following beneficial effects:

from the embodiment 1, the rolling mill with the working rolls with different diameters is adopted to roll the strip foil, so that the thinning of the strip foil is facilitated, the better plate shape is obtained, and the cognition of the technical personnel in the field on the working rolls of the rolling mill is broken through. In addition, the invention enables the strip foil to form a coating arc on the working roll at the inlet side of the roll gap of the unequal-diameter working roll, and the front tension is uniformly distributed on the cross section of the coating arc at the inlet side through the back support of the working roll to the strip foil, thereby realizing the uniform rolling of the strip foil, breaking through the bottleneck restricting the strip foil to develop towards a wider, thinner and more ideal plate shape direction, and solving the technical problem which is difficult to solve for a long time in the industry, thereby having great application value and economic value. In addition, the strip foil is not horizontally arranged along the rolling center line, so that the cognition in the industry is broken, and the strip foil is creative per se.

From the embodiment 2, the strip foil forms the wrapping arc on the roll surface of the working roll at the outlet side of the roll gap of the working roll with different diameters, so that the uniform distribution of the post-tension on the wrapping arc at the outlet side is realized, the defects of waves, wrinkles and the like are eliminated at the key forming initial stage of the strip foil rolling, and then the strip foil is backed up by the working roll, so that the strip shape of the strip foil is stabilized at the later stage of the rolling forming, and a better strip shape is obtained.

It can be seen from examples 3 and 4 that the present invention combines the uniform opening action of the inlet-side clad arc and the outlet-side clad arc, overcomes the disadvantages caused by the unequal diameter work roll manufacturing based on the beneficial effects of examples 1 and 2, and not only solves the problem of curling deformation of the strip foil, but also unexpectedly solves the problem of different brightness of the upper and lower plate surfaces of the strip foil.

More importantly, the slippage thinning of the invention not only has the effect of extrusion thinning, but also has the effect of rolling thinning, and the neutral surface is stabilized at the middle layer part of the band foil, thereby ensuring the uniformity of the mechanical property of the band foil. The invention breaks through the strict requirement on the rolling center line in the national standard, really realizes the stability of the neutral surface in an engineering way, and solves the technical problem which can not be solved by the prior art, thereby having creativity.

For rolling of extremely thin strip foils, basically zero roll gap or negative roll gap rolling is performed, and it is very difficult to thin the strip foils and ensure the stability of the strip shapes, which is the core problem to be solved by the invention. The invention adopts the rolling scheme of the unequal-diameter working roll, which is beneficial to overcoming the defects, is beneficial to thinning the strip foil and obtaining better plate shape, and has the technical effect which cannot be achieved by the existing equal-diameter working roll. The invention is undoubtedly a technical breakthrough for the rolling of high-precision wide-width strip foils which have long been trapped in technical bottlenecks.

It is known that the thinner the strip foil, the more difficult it is to control the rolled profile. At present, the industry does not use the extreme for breaking through the limit, but no effective solution is found. The significance of the invention using the unequal-diameter working rolls is that although a part of the reduction of the strip foil is sacrificed, the rolling pass (the times of the reciprocating rolling) is slightly increased, the important significance is that the strip shape is kept stable, and the rolling defect caused by the increase of the width is avoided or reduced, which is significant for the high-precision rolling of the wide strip foil.

In addition, the invention adopts the unequal-diameter working rolls to roll the strip foil, breaks through the cognition and the prejudice of technicians in the field on the working rolls of the rolling mill, and provides a new idea for the design of the rolling mill and the improvement of the rolling process. The rolling method of the invention also overcomes the defects caused by rolling with unequal-diameter working rolls and provides a new technical solution for rolling the wide high-precision strip foil.

The invention breaks through the technical bottleneck and provides a new technical solution for rolling the wide-width high-precision strip foil.

Drawings

Fig. 1 is a schematic view of the tension distribution applied in an ideal state on a cross section of a strip foil.

Fig. 2 is a schematic view of the tension distribution actually applied to the cross section of the strip foil.

Fig. 3 shows a typical arrangement of current foil rolling.

Fig. 4 is a schematic structural diagram of a work roll of a conventional rolling mill.

Fig. 5 is a schematic structural view in embodiment 1 of the present invention.

Fig. 6 is a schematic view of a belt drive.

FIG. 7 is a force analysis graph of a volume element on a clad arc.

FIG. 8 is a force analysis plot of a volume of cells with foil in an unsupported state.

Fig. 9 is a force analysis diagram of a volume unit with the foil in the backed state.

FIG. 10 is a tension distribution diagram in the thickness direction of a certain volume unit on the arc of the entry side cladding of the roll gap in example 1.

FIG. 11 is a graph of the flow velocity profile of the upper and lower layers of tape foil in the calendering zone.

Fig. 12 is a schematic structural view in embodiment 2 of the present invention.

FIG. 13 is a tension distribution diagram in the thickness direction of a certain volume unit on the exit side of the roll gap in the coating arc of example 2.

Fig. 14 is a schematic structural view in embodiment 3 of the present invention.

FIG. 15 is a tension distribution diagram in the thickness direction of a certain volume unit on the exit side of the roll gap in the coating arc of example 3.

FIG. 16 is a schematic diagram of slip thinning.

Fig. 17 is a schematic structural view in embodiment 4 of the present invention.

Fig. 18 is a partially enlarged schematic view of fig. 17.

In the figure: 1. an upper work roll; 2. a lower working roll; 3. flattening rollers; 4. a lifting roller; 5. a tape foil; 6. rolling a central line; 7. a driving pulley; 8. a belt; 9. a volume unit.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "front", "rear", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are for convenience of description only, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Example 1:

a rolling method of wide metal strip foil is used for rolling copper alloy strip foil, the final rolling thickness of the copper alloy strip foil is 0.01mm, and the width is 800 mm. The thickness of the boundary between the strip and the foil is 0.15mm, and the thickness of the copper alloy strip foil (hereinafter referred to as strip foil) belongs to the foil. Because the copper alloy has large deformation resistance, it is difficult to ensure the flatness of the plate shape.

As shown in fig. 5, a flattening roll 3 is provided on the entrance side of the roll gap, the roll surface of the flattening roll 3 is lower than the rolling center line 6, and the strip foil 5 passes through the flattening roll 3 and is stretched and then obliquely upward into the roll gap formed by a pair of work rolls, wherein the roll diameter of the upper work roll 1 is 30mm, the roll diameter of the lower work roll 2 is 60mm, the roll diameter of the lower work roll 2 is 2 times the roll diameter of the upper work roll 1, and in order to prevent the upper and lower plate surfaces of the strip foil 5 from curling into a plate shape due to the difference in the rolling linear velocity, the roll surfaces of the upper work roll 1 and the lower work roll 2 have the same linear velocity during rolling. Because the strip foil 5 forms a certain included angle with the rolling central line 6 before entering the roll gap, the strip foil 5 forms an inlet side coating arc on the roll surface of the lower working roll 2, and the coating angle of the inlet side coating arc is alpha, and alpha is 30 degrees. Due to the existence of the inlet-side coating arc, the lower working roll 2 backs up the strip foil 5, and the tension is uniformly distributed on the cross section of the inlet-side coating arc, and the principle is as follows:

as shown in fig. 6, in the transmission of the belt 8, the driving pulley 7 drives the belt 8 to rotate clockwise, point a is an entry point of the belt 8 into the driving pulley 7, and point B is an exit point of the belt 8 from the driving pulley 7. The frictional force generated by the driving pulley 7 on the belt 8 is cumulatively increased in the entrance-side coating arc from the point a to the point B, so that the tension F2 of the belt 8 at the point B is smaller than the tension F1 thereof at the point a, and the larger the coating angle of the entrance-side coating arc, the larger the difference between F1 and F2 is, which results in that the belt 8 at the point B side is always in a slack state and the belt 8 at the point a side is always in a tensioned state.

For the same reason, as shown in fig. 7, during rolling, the strip foil 5 enters the roll gap from the left side, the neutral point P is in the rolling arc, and the linear velocity of the work roll surface is greater than the linear velocity of the strip foil 5 entering the roll gap on the left side of the neutral point P, which generates a velocity difference and a friction force F3, i.e., the lower work roll 2 rotates the strip foil 5 along the inlet-side wrapping arc, as the belt 8 drives. In the figure, a volume element 9 is arbitrarily taken on the inlet side coating arc, and due to the friction force F3, the tension F2 acting on the volume element 9 is smaller than the tension F1 acting on the far end of the volume element, wherein the near end tension and the far end tension are expressed relative to the distance from the roll gap. For the next volume element 9 to the right of this volume element 9, the magnitude of the distal tension acting on this volume element 9 is equal to F2, the magnitude of the proximal tension is smaller than F2, and so on, due to the cumulative increase in friction F3. It follows that the friction force F3 increases cumulatively from point a (the start of the entry-side cladding arc) to point B (the end of the entry-side cladding arc), and correspondingly the proximal tension F2 experienced by the tape foil 5 on the volume element 9 decreases progressively from point a to point B.

As shown in fig. 8, in the figure, one volume element 9 is provided on the tape foil 5, and due to the non-uniformity of the tension, the tension of the two side portions of the volume element 9C, D is greater than that of the middle E portion, and the E portion bulges to form a wave. In the case of suspended tensioning of the band foil 5, the proximal tension F2 is equal to the distal tension F1, at which the volume elements 9 are contracted inward in the width direction, the internal force F4 of which is negative.

As shown in fig. 9, when the volume unit 9 enters the inlet-side cladding arc, the lower work roll 2 applies a back-supporting force T thereto, and the volume unit 9 is bent and deformed. As the proximal tension F2 gradually decreases, the internal force F4 acting in the width direction of the volume element 9 changes from negative to positive and gradually increases. The increase of the internal force F4 causes the volume elements 9 to spread outward in the width direction as if the loose rubber band widened in the width direction, thereby flattening the corrugated portion of the belt foil 5. In the flattening process, the near-end tension acting on two side parts of the volume unit 9C, D is rapidly reduced, two side parts of C, D extend outwards along the width direction, so that the middle part E is in contact with the roller surface of the lower working roller 2, and after the part E is in contact with the lower working roller 2, the near-end tension of the middle part of the volume unit 9 is correspondingly increased, and further the uniform distribution of the near-end tension F2 on the cross section of the volume unit 9 is realized. As can be seen from fig. 6, the proximal tension F2 in the roll gap rolling zone is the front tension of the rolling, where the front tension is the smallest and the front tension is the most uniform in the cross section. It can also be seen that the larger the wrap angle of the inlet side wrap arc, the smaller the front tension in the nip rolling zone, and the more evenly the front tension is distributed.

In rolling, a larger front tension facilitates control of the shape of the strip. The presence of the entry-side wrapping arc, although distributing the front tension evenly over the cross section of the strip foil 5, loses part of the front tension and therefore requires the coiler or the flattening roll 3 to add the appropriate front tension to the strip foil 5 to compensate for the loss. The tension of the leading end of the inlet side coating arc can be increased to 50-60% of the yield strength of the material during rolling, and the thin strip foil 5 is pulled by fully utilizing the thinning effect of the tension on the strip foil 5. For rolling of the strip foil 5, which is basically seamless rolling, the rolling process of the strip foil 5 by the working rolls can be regarded as a repeated thinning and widening process of the strip foil 5, and the coiling machine and the flattening roll 3 can be regarded as a repeated elongated narrowing process of the strip foil 5, so that the appropriate increase of the front tension of the strip foil 5 is more beneficial to the thinning and the shape control of the strip foil 5.

It should be noted that the proximal tension F2 varies in a gradient in the thickness direction, as shown in fig. 10, the side of the entrance-side clad arc in contact with the lower work roll 2 has a low tension and the side of the entrance-side clad arc away from the lower work roll 2 has a high tension, which compensates for the loss of the front tension to some extent, and the compensation effect is more significant especially for thicker strip materials.

As shown in fig. 11, the hatched portion is a deformed region. When the band foil 5 enters a deformation area of a roll gap, the band foil 5 is extruded by a working roll to start deformation, because of the existence of an inlet side coating arc, the deformation amount of an upper layer of the band foil 5 is larger than that of a lower layer, the linear velocity of a mass point of the upper layer at a neutral point P is consistent with that of the roll surface of an upper working roll 1, the plate surface of the lower layer lags, and the linear velocity of the mass point at a point E is consistent with that of the roll surface of a lower working roll 2, so that the outflow speed of the upper layer of the band foil 5 is larger than that of the lower layer of the band foil 5, and the band foil 5 curls towards one side of the lower working roll 2, which indicates that a layer shift phenomenon exists in a rolling area. The layer shift phenomenon deflects the neutral surface of the band foil 5 toward the lower layer, and causes the band foil 5 to be deformed by curling. The curling deformation is obvious on a strip with larger plate thickness, but is not obvious on a foil with the thickness less than 0.15mm, and can be corrected through the subsequent procedures of flattening, straightening and the like.

The deviation of the neutral plane causes the mechanical properties of the strip foil to be uneven, and it is known from the background art that it is difficult to achieve the stability of the neutral plane in actual production, and since it is difficult, it is not necessary to specify the way the strip foil enters the roll gap according to the national standard. For some application fields, the requirement for the mechanical property of the tape foil is not high, such as the use of copper tape foil for conduction, or for decoration, corrosion prevention, etc., and it is not necessary to have too high requirement for the uniformity of the mechanical property of the tape foil at all. Therefore, in the present invention, the strip foil 5 does not enter the roll gap horizontally along the rolling center line 6, which itself has broken the recognition in the industry, and is therefore inventive.

As is clear from fig. 11, the upper work roll 1 has a small roll diameter and a large press-in amount to the band foil 5, and is particularly advantageous for thinning the band foil 5 and reducing the total number of passes of rolling, but the upper work roll 1 has a large tendency to bend laterally and is disadvantageous for the lubricating medium to be uniformly introduced into the roll gap. The lower working roll 2 has small lateral bending tendency, so that the lubricating medium can be uniformly brought into a roll gap, and the uniform tension action of the cladding arc on the band foil 5 is superposed, so that the band foil 5 can obtain a better plate shape, but the roll diameter of the lower working roll 2 is large, the pressing amount on the band foil 5 is small, and the rolling of the band foil 5 is not facilitated. This embodiment combines the advantages of large diameter work rolls and small diameter work rolls: compared with the traditional working roll with the same diameter as the upper working roll 1, the increase of the roll diameter of the lower working roll 2 is beneficial to obtaining better plate shape; compared with the traditional working roll with the same diameter as the lower working roll 2, the reduction of the roll diameter of the upper working roll 1 has large pressing amount to the band foil 5, thus being beneficial to the rolling thinning of the band foil 5. Accordingly, the present embodiment also focuses on the disadvantages of the large-diameter work roll and the small-diameter work roll: compared with the traditional working roll with the same diameter as the upper working roll 1, the increase of the roll diameter of the lower working roll 2 is not beneficial to the thinning of the strip foil 5. The reduction of the diameter of the upper work roll 1 is detrimental to obtaining a better profile shape, compared to the conventional work roll having the same diameter as the lower work roll 2. It can be said that the advantages and disadvantages of the large-diameter working roll and the small-diameter working roll are a group of irreconcilable contradictions.

The three basic conditions for stable rolling of the rolling mill are the roller system precision, the lubrication condition and the tension precision respectively. Under the condition that the accuracy of the roller system and the accuracy of the tension cannot be continuously improved, the improvement of the lubricating condition plays a crucial role in the stability of the plate shape. As can be seen from fig. 11, the lubrication condition is related to the size of the biting angle. At the entrance of the deformation zone, the biting angle of the lower working roll 2 is small, and a wedge-shaped gap formed by the lower working roll and the lower plate surface of the band foil 5 is more favorable for the entering of lubricating oil, so that the oil wedge effect is generated, and the stable bearing capacity is established. In addition, the downward-pressing extension arc length is long, the contact surface is large, and the arc length fluctuation along the width direction of the strip foil is small, so that the stability of the plate shape is facilitated. Although the wedge-shaped gap formed between the upper working roll 1 and the upper plate surface of the band foil 5 is not beneficial to establishing stable bearing capacity relative to the lower working roll 2, the stability of the plate shape of the lower plate surface of the band foil 5 plays a role in restraining the upper plate surface, and is beneficial to the stability of the plate shape on the whole. In summary, the major contribution of the small-diameter work roll is to the thinning of the strip foil, while the major contribution of the large-diameter work roll is to stabilize the overall shape of the strip foil and reduce the generation of defects such as waves and wrinkles. Overall, although a small amount of thinning is sacrificed, stabilization of the overall plate shape is advantageous.

For very thin strip foils of thickness 0.01mm and below, which are basically rolled with a negative roll gap, the reduction is no longer decisive. In addition, due to the rebound of the deformation area, the thinning of the strip foil cannot be effectively realized by using the conventional equal-diameter working roll with larger roll diameter, and only the working roll with smaller roll diameter can be adopted. However, if the existing equal-diameter working roll with smaller roll diameter is adopted, the width rolling of the strip foil cannot be realized, and the width rolling causes plate surface defects, which is the bottleneck restricting the high-precision wide-width strip foil rolling at present. It is well known in the industry that the thinner the strip foil, the more difficult it is to control the rolled profile. At present, in the industry, in order to break through the limit, the limit is not used at all, but no effective solution is found. The significance of the invention using the unequal-diameter working rolls is that although a part of the reduction of the strip foil is sacrificed, the rolling pass (the times of the reciprocating rolling) is slightly increased, the important significance is that the strip shape is kept stable, and the rolling defect caused by the increase of the width is avoided or reduced, which is significant for the high-precision rolling of the wide strip foil.

From the embodiment 1, the strip foil 5 forms an inlet-side coating arc on the lower working roll 2 at the inlet side of the roll gap, the tension is uniformly distributed on the cross section of the inlet-side coating arc through the back support of the lower working roll 2 to the strip foil 5, the uniform rolling of the strip foil 5 is realized, the bottleneck limiting the development of the strip foil 5 in the direction of a wider, thinner and more ideal plate shape is broken through, and the technical problem which is difficult to solve for a long time in the industry is solved, so that the strip foil has great application value and economic value. The invention rolls the strip foil by adopting the rolling mill with the working rolls with different diameters, which is not only beneficial to thinning the strip foil, but also beneficial to obtaining better plate shape.

It should be noted that forming the strip foil 5 into an entry-side wrap arc on the lower work roll 2 is not limited to the flattening roll 3, but includes all pre-machine adjustment rolls, such as an S-roll, a high-low roll, or a combination thereof. The strip foil 5 can form an inlet side coating arc on the lower working roll 2 only by adjusting a front adjusting roll closest to the roll gap to form a certain included angle between the strip foil 5 and the rolling central line 6 before entering the roll gap. In the present embodiment, the inlet-side coating arc is formed on the lower work roll 2, and the inlet-side coating arc may be formed on the upper work roll 1 by the same principle.

Example 2:

as shown in fig. 12, this embodiment is different from embodiment 1 in that the band foil 5 horizontally enters the roll gap along the rolling center line 6, the flattening rolls 3 are provided on the exit side of the roll gap, and the roll surfaces of the flattening rolls 3 are higher than the rolling center line 6. The flattening roll 3 post-tensions the strip foil 5 so that the strip foil 5 forms an exit-side wrap arc on the roll surface of the upper work roll 1, and the wrap angle of the exit-side wrap arc is β, which is also 30 °. Due to the existence of the outlet-side coating arc, the upper working roll 1 backs up the strip foil 5, and the tension is uniformly distributed on the cross section of the outlet-side coating arc, and the principle is as follows:

as shown in fig. 13, the band foil 5 flowing out from the nip is wrapped around the upper work roll 1 to form an exit-side wrapping arc. Since the linear velocity V of the outgoing tape foil 5 is greater than the linear velocity of the roll surface of the upper work roll 1, the upper work roll 1 generates a reverse frictional force F4 to any volume element 9 on the exit side wrapping arc, and a proximal tension F5 and a distal tension F6 are applied to the volume element 9. As described in example 1, the frictional force F4 increases gradually from point M to point N, and likewise, the distal tension F6 increases accordingly. The distal tension F6 reaches a maximum at point N, where the distal tension F6 is the posterior tension. The post-tension can not only prevent the deviation of the strip foil 5, but also reduce the rolling pressure, and is beneficial to the high-speed rolling of the strip foil 5. Because the linear speed of the outgoing line of the band foil 5 is greater than that of the roll surface of the working roll when the band foil 5 flows out of the roll gap, the band foil 5 can be understood as a belt, the upper working roll 1 is understood as a driven pulley, then, the band foil 5 drives the upper working roll 1 to rotate, if the belt drives the driven pulley to rotate, the larger the wrapping arc at the outlet side is, the larger the transmission torque is, so that the torque of the upper working roll 1 is reduced, and the energy consumption of a main motor is reduced.

It is particularly important that the strip foil 5 is subjected to a gradually increasing back tension after it has exited the nip, which, based on the mechanism in example 1, is the smallest at the exit of the nip and the distribution of the back tension is the most uniform here over the cross-section, which is important for the control of the strip shape of the strip foil 5. As can be known from the discussion in the background art, the defects of waves, wrinkles and the like of the plate shape can be prevented only by uniformly distributing the tension on the cross section of the strip foil, but the invention realizes the uniform distribution of the tension at the roll gap outlet by coating the strip foil 5 on the roll surface of the upper working roll 1, and the defects of waves, wrinkles and the like are eliminated at the early stage of the forming of the strip foil rolling, so that the better plate shape can be obtained. With the continuous outflow of the volume units 9, the far-end tension F6 acting on the cross section of the volume units 9 is gradually increased, the uneven tension trend is obvious, but the back support action of the upper working roll 1 on the strip foil 5 prevents the strip foil 5 from suspending and shaking, stabilizes the plate shape in the key forming period of the strip foil rolling, and further prevents the defects of waves, wrinkles and the like caused by uneven tension of the plate shape.

From the embodiment 2, the invention enables the strip foil 5 to form the outlet side wrapping arc on the roll surface of the upper working roll 1 at the outlet side of the roll gap, realizes the uniform distribution of the back tension on the outlet side wrapping arc, eliminates the defects of wave, wrinkle and the like at the key forming initial stage of the strip foil rolling, and then stabilizes the plate shape of the strip foil 5 at the later stage of the rolling forming through the back support of the upper working roll 1 to the strip foil 5, thereby obtaining better plate shape. In addition, the torque of the upper work roll 1 is reduced, reducing the energy consumption of the rolling mill.

It should be noted that forming the strip foil 5 into the exit-side wrap arc on the upper work roll 1 is not limited to the flattening roll 3, but includes all post-machine leveling rolls, such as an S-roll, a high-low roll, or a combination thereof. The strip foil 5 can form an outlet side coating arc on the upper working roll 1 only by adjusting the 2-machine rear adjusting roll closest to the roll gap to enable the strip foil 5 to form a certain included angle with the rolling central line 6 after coming out of the roll gap. In the present embodiment, the exit-side clad arc is formed on the upper work roll 1, and the exit-side clad arc may be formed on the lower work roll 2 for the same reason.

Example 3:

this example can be regarded as a combination of examples 1 and 2, and as shown in fig. 14, the strip foil 5 forms an entrance-side clad arc with the lower work roll 2 on the entrance side of the roll gap, and the clad angle α of the entrance-side clad arc is 30 °; the strip 5 forms an outlet-side wrap arc with the upper work roll 1 on the outlet side of the roll gap, the wrap angle β of which is also 30 °. Due to the existence of the inlet-side wrapping arc and the outlet-side wrapping arc, the lower working roll 2 and the upper working roll 1 respectively back-support the strip foil 5.

The role and influence of the entry-side clad arc in rolling have been described in example 1, and the role and influence of the exit-side clad arc in rolling have been described in example 2, and will not be described again here. It is noted that, as shown in fig. 13, at the exit side of the nip, the linear velocity of the lower layer of the volume element 9 is greater than the linear velocity of the upper layer of the volume element 9, and a frictional force F4 acts on the upper layer face of the volume element 9, whereby it can be concluded that the wrapping arc exerts a reverse straightening effect on the curling deformation of the tape foil 5, which to some extent eliminates the curling effect of the layer shift phenomenon on the tape foil 5.

In the production of the strip foil 5, it is necessary to repeatedly roll the strip foil 5 in a plurality of passes, and due to the phenomenon of layer shift, the strip foil 5 is deformed in a one-way curl after each pass of rolling, and although the upper work rolls 1 can reverse-straighten the curl, the curl is not sufficiently removed, and therefore, an improvement is required in the rolling method.

As can be seen from fig. 11, 14, and 15, when the first pass of rolling of the strip foil 5 is completed from left to right, the outflow rate of the upper layer of the strip foil 5 is higher than the outflow rate of the lower layer of the strip foil 5, and the strip foil 5 curls toward the lower work roll 2. After the second pass of rolling of the strip foil 5 is finished from right to left, the outflow speed of the upper layer of the strip foil 5 is smaller than that of the lower layer of the strip foil 5, the strip foil 5 is curled towards one side of the upper working roll 1, so that the curling of the first pass of rolling is reversely corrected, and the like. As can be seen from the above, the total rolling pass of the strip foil 5 is set to an even number of passes, and the curling deformation of the strip foil 5 can be eliminated to the maximum extent.

What is important is that after the first rolling, the neutral surface of the band foil 5 deviates to one side, then the second rolling makes reverse correction to the deviated neutral surface, and after the multiple even rolling, the neutral surface is stabilized at the middle layer part of the band foil 5, thereby ensuring the uniformity of the mechanical property of the band foil 5. By the method, the strict requirement on the rolling center line 6 in the national standard is avoided, the stability of the neutral surface of the band foil 5 is really realized in an engineering way, and the technical problem which cannot be solved in the prior art and the embodiment 1 is solved.

As shown in fig. 4, in the conventional rolling, there is no speed difference in the speed of the strip foil 5 flowing out from the roll gap, and the thinning process can be regarded as squeezing, like squeezing toothpaste. Whereas in the present invention the speed of the strip 5 exiting the nip is a difference in speed, the process of thinning the strip 5 is more like reverse rolling of the upper and lower layers of the strip 5, as with a rolling pin. As shown in fig. 16, in the repeated rolling process, the upper and lower layers of the band foil 5 are not only pressed by the roll gap but also subjected to a relative tensile force, so that the upper and lower layers of the band foil 5 slip to finally reduce the thickness. The sliding thinning has the effect of extrusion thinning and the effect of rolling thinning, and compared with the traditional extrusion thinning, the plate shape is better, and the control of the plate shape is easier to realize.

As can be seen from example 3, the present invention solves the problem of curling deformation of the strip foil 5 well, and more importantly, the sliding thinning of the present invention has both the effect of extrusion thinning and the effect of roll thinning, and the neutral surface is stabilized at the middle layer of the strip foil 5, thereby ensuring the uniformity of the mechanical properties of the strip foil 5. The invention breaks through the strict requirement on the rolling center line in the national standard, really realizes the stability of the neutral surface in an engineering way, and solves the technical problem which can not be solved by the prior art.

In example 3, the outlet-side clad arc reduces the torque of the upper work roll 1, but the inlet-side clad arc increases the torque of the lower work roll 2, resulting in a difference in the drive torques of the upper and lower work rolls, which increases the energy consumption of the entire rolling mill. Therefore, the technical scheme is continuously improved:

example 4:

as shown in fig. 17, this embodiment is different from embodiment 3 in that both the entry-side shroud arc and the exit-side shroud arc are formed on the lower work roll 2. As can be seen from fig. 17, the entrance-side clad arc increases the torque of the lower work roll 2, while the exit-side clad arc decreases the torque of the lower work roll 2, and therefore, the driving torque applied to the lower work roll 2 is not changed as a whole.

As shown in fig. 18, since the roll diameter of the upper work roll 1 is smaller than that of the lower work roll 2, both the entrance-side shroud arc and the exit-side shroud arc are formed on the lower work roll 2, and therefore the thinning effect of the upper work roll 1 on the band foil 5 is the greatest. However, this embodiment has the disadvantage that the unidirectional curling of the strip foil 5 is greater than in the above-described exemplary embodiments due to the superposition. To overcome this drawback, the solution is to turn the strip 5 over before each pass of rolling and then to feed the strip 5 into the roll gap for rolling. In this way, the rolling deformation of the strip foil 5 occurring in the previous rolling can be eliminated by the reverse rolling. The difference between the turn-over rolling and the existing rolling is that the plate surfaces of the strip foils 5 rolled by the upper working roll 1 and the lower working roll 2 are different in the two adjacent passes of rolling. In order to ensure the consistency of the properties of the upper and lower surfaces of the strip foil 5, the total rolling pass of the strip foil 5 is likewise set to an even number of passes.

By adopting the method, on one hand, the torque of the upper working roll and the lower working roll is balanced, and on the other hand, the curling deformation generated during rolling of the strip foil 5 is eliminated. It is particularly noted that since the contact length and the force applied to the upper and lower plate surfaces of the band foil 5 and the upper and lower work rolls are the same due to the face-over rolling, the problem of the difference in the brightness between the upper and lower plate surfaces of the band foil 5 is unexpectedly solved, which is not solved in the above-described embodiment.

It should be noted that the above embodiments are all exemplified by the rolling of a strip foil with a thickness of 0.01mm, which does not prevent the invention from being able to roll thicker strips, the principle and function of which are the same.

The details of which are not described in the prior art. Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A rolling method of wide metal strip foil is characterized in that: using a rolling mill with unequal-diameter working rolls, wherein the roll diameter of one working roll of the rolling mill is larger than that of the other working roll; during rolling, the linear velocities of the roll surfaces of the two working rolls are the same, the metal strip foil is coated on the roll surface of a certain working roll at the inlet side or the outlet side of a roll gap formed by the two working rolls to form a coating arc, and the tension is uniformly distributed on the cross section of the coating arc through the back support of the working rolls on the metal strip foil.

2. A method of rolling a wide width metal strip foil as claimed in claim 1, wherein: the metal strip foil is coated on the surface of the working roll with the larger roll diameter to form a coating arc.

3. A method of rolling a wide width metal strip foil as claimed in claim 1, wherein: the wrap arc is achieved by changing the angle at which the metal strip foil enters or exits the nip.

4. A method of rolling a wide width metal strip foil as claimed in claim 1, wherein: the coating angle of the coating arc is alpha, and alpha is more than 0 degree and less than or equal to 90 degrees.

5. A method of rolling a wide width metal strip foil as claimed in claim 1, wherein: and coating the metal strip foil on the roll surface of the same or different working rolls at the inlet side and the outlet side of the roll gap to form an inlet side coating arc and an outlet side coating arc.

6. A method of rolling a wide metal strip foil as claimed in claim 5, wherein: and the metal strip foil is coated on the surface of the working roll with the larger roll diameter.

7. A method of rolling a wide metal strip foil as claimed in claim 5, wherein: the entry-side wrap arc is obtained by varying the angle at which the foil enters the nip and the exit-side wrap arc is obtained by varying the angle at which the foil exits the nip.

8. A method of rolling a wide width metal strip foil as claimed in claim 1, wherein: the diameter of the working roll with larger roll diameter is 1.5 to 5 times of the diameter of the working roll with smaller roll diameter.

9. A method of rolling a wide width metal strip foil as claimed in any one of claims 1 to 8, wherein: before the next rolling, the metal strip foil is turned over and then enters a rolling mill for rolling.

10. A method of rolling a wide width metal strip foil as claimed in claim 9, wherein: the total rolling passes of the metal strip foil are even number of times.