CN113290052B - Rolling method of wide metal strip foil - Google Patents

Abstract

A rolling method of a wide metal strip and foil, using a rolling mill with unequal diameter work rolls, the roll diameter of a certain work roll of the rolling mill is larger than the roll diameter of another work roll; The roll surfaces of the rolls have the same linear speed, and at the entrance or exit side of the roll gap formed by the two work rolls, the metal strip foil is wrapped on the roll surface of a certain work roll to form a cladding arc. Metal tape foil backing, so that the tension is evenly distributed in the cross-section of the cladding arc. The invention uses a rolling mill with unequal-diameter work rolls to roll the strip and foil, which is not only beneficial to thinning the strip and foil, but also beneficial to obtaining a better plate shape. In addition, the present invention enables the strip foil to form a cladding arc on the working roll, and through the back support of the strip foil by the working roll, the front tension is evenly distributed on the cross section of the cladding arc at the entrance side, realizing the uniform stretching of the strip foil Rolling breaks through the bottleneck that restricts the development of strip and foil in the direction of wider, thinner and more ideal shape, and solves the technical problems in the industry.

Description

A rolling method of wide metal strip and 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 to obtain good plate shapes.

Background technique

With the advancement of the technology industry, the market demand for high-precision wide-width thin strips and foils (hereinafter referred to as strips and foils) is becoming more and more urgent. Under the current technical background, the rolling technology for wide and thick strips is basically mature, but the technical bottleneck has emerged in the rolling technology of high-precision wide and thinner strips and foils, and a breakthrough is urgently needed. For thicker strips, even if there are shape defects after rolling, the shape can still be corrected by tension leveling or other leveling means, while for thinner strips and foils, especially very thin foils, due to lack of follow-up The shape correction means, the original rolling shape is the final shape of the product. Especially for strips and foils with high deformation resistance such as copper, copper alloys, and stainless steel, it is difficult to achieve stable high-quality production due to the restriction of the shape control ability of the existing rolling technology. According to known information, the thinnest rolling thickness that can be achieved in mass production of pure copper foil is 0.006mm, and the maximum width is 650mm. The minimum rolling thickness that can be achieved in mass production of stainless steel foil is 0.02mm, and the maximum width is 600mm. Moreover, the shape of the rolled plate is not very good. If the width continues to increase, the shape of the plate will become worse.

The three basic conditions for stable rolling of rolling mills are roll system accuracy, lubrication conditions and tension accuracy. For the rolling of ultra-thin strip and foil, the thinning effect of the reduction is weakened, and the thinning of the strip and foil thickness basically depends on the flattening rebound of the work roll, rolling speed, and larger unit tension. The tension selected for thicker strip rolling usually does not exceed 16% of the yield strength of the strip, so the effect of tension on strip thinning is not obvious, and its main function is to establish a stable rolling operation state. However, there is a big difference in the strip and foil rolling of extremely thin thickness. In order to make full use of the thinning effect of tension on the strip and foil, the unit tension used even reaches 60% of the yield strength of the material. Since the large tension has a great effect on the thinning of the strip and foil, it naturally has a great influence on the shape of the rolled plate. The influence of the tension on the shape of the strip is mainly manifested in the uniformity of the distribution of the tension on the cross-section of the strip and foil.

As shown in Figure 1, in an ideal situation, on the cross-section of the strip foil (including the edge), the tension per unit width is uniform and consistent, but this is not the case in actual production. The actual tension distribution is shown in Figure 2. In Figure 2, the distribution of tension on the cross-section of the foil is not uniform. The tension value at the two edges of the foil is the largest, while the tension value in the middle is relatively small. ΔT in the figure is the tension The difference between the maximum value and the minimum value distributed along the width B direction of the strip foil, the ratio ΔT/B can be called the non-uniformity of tension. There are many factors that cause the uneven tension of the strip foil on the cross section. One type of factor comes from the unevenness of material composition, structure and annealing. This type of factor is random; the other type of factor comes from rolling conditions. There are regularities to be found, such as the sudden decrease in the edge thickness of the strip and foil during the multiple thinning and rolling process. This phenomenon is recorded in the paper "Three-dimensional Analysis of Cold Rolled Strip Deformation". Through the finite element method, the edge drop and lateral flow change with the edge distance of the plate after rolling are simulated and calculated. For details, see the third issue of "Rolling Steel" in 1999. According to the roll pressure formula: It can be seen that the fluctuation of the thickness of the region is accompanied by the lateral flow of the metal material (shown as an abnormal plate shape in the macroscopic view), the lateral flow of the metal material causes the fluctuation of the rolling force P1 in the region, and the fluctuation of the rolling force P1 causes the fluctuation of the rolling force P1 in the region. The tension of S1 fluctuates. Then, conversely, the fluctuation of the tension S1 in the region will lead to the fluctuation of the rolling force P1, and the fluctuation of the rolling force P1 will affect the lateral flow of the metal material, which is mutual cause and effect. This shows that in the rolling process, the tension applied to the cross-section of the strip foil is not uniform, and the non-uniformity of this tension is ubiquitous.

In the rolling process, the pre-tension and post-tension have a great influence on the shape of the strip, which is recorded in the paper "The Influence of Tension on the Deformation of Cold-rolled Strip", which discusses in detail through the three-dimensional simulation system Increasing the front and rear tension to limit the lateral flow of metal can increase the thickness deformation of the strip and make the section thickness more uniform. For details, see the fourth issue of volume 35 of "Steel". For the strip foil, increasing the front tension and the back tension has a greater influence on the shape of the strip foil. If the strip foil has uneven tension on the unit width, the deformation resistance, roll gap, and material thickness of the local rolling will be uneven, which will eventually lead to defects (including potential defects) in the rolled plate shape. For example, in the rolling process, often Appearing waves, wrinkles. What's more serious is that the drastic change of the tension in the regions on both sides will cause cracks to appear on both sides of the ribbon foil. Once a crack occurs, it will quickly extend laterally, thereby causing the ribbon foil to break. The wider the strip and foil, the greater the unevenness of the tension, and the more difficult it is to control the shape of the strip. This is currently the technical bottleneck that restricts the development of the strip and foil to a wider, thinner, and more ideal strip shape. It is also a long-term difficulty in the industry. The technical problem to be solved, and how to make the tension evenly distributed on the cross section of the strip foil is the key to solving the problem.

As shown in Figure 3, this is the typical layout of strip foil rolling at present. Regardless of domestic or foreign countries, the strip foil 5 enters horizontally along the rolling center line 6 after being pre-stretched by the lifting roller 4 and the flattening roller 3. in the roll gap. It can be seen from Figure 3 that before the strip foil 5 enters the roll gap, the section of strip foil between the lower work roll 2 and the flattening roll 3 is always in a suspended and tight state, so as to solve the problem of the tension on the cross section of the strip foil here. Uneven distribution is very important and directly affects the success or failure of high-precision wide-width strip and foil rolling. According to the national standard, the error of the high level of the rolling center line 6 is required to be within 0.05mm/m. The reason for such a high requirement is to ensure the stability of the neutral plane of the strip to achieve uniform mechanical properties of the strip. However, this is difficult to achieve in actual production. Factors such as the shaking of the lifting roll under the action of the oil cylinder, the roll diameter error of the flattening roll and the working roll, and the suspension of the strip will cause the neutral plane of the strip to deviate to a certain position. On the other hand, this deviation phenomenon is especially serious for thinner strips and foils, and there is no better solution at present.

In addition, as shown in Figure 4, both domestic and foreign, the upper work roll 1 and the lower work roll 2 of the rolling mill are designed with equal diameters, from two-high mills to twenty-high mills. This design is beneficial to the maintenance and exchange of work rolls, and for the rolling mill, its transmission structure is thus simplified. The size of the work roll diameter has an influence on the rolling of the strip. It is well known that the smaller the diameter of the work roll, the more favorable it is for the thinning of the strip foil 5, but it also brings problems: in Figure 4, the diameter of the left work roll is small, the stiffness is small, and the bite angle of the strip foil 5 Large, the lateral component of the rolling force is large, so its lateral bending tendency is large. In addition, the length of the biting arc of the left working roll to the strip foil 5 is short, which is not conducive to the uniform introduction of the lubricating medium into the roll gap, resulting in uneven thickness of the oil film in the rolling arc area. These factors lead to large fluctuations in the arc length of the rolling arc along the width direction of the strip foil, which eventually leads to defects in the shape of the rolled strip. Under the same conditions, the right working roll has a large diameter and high rigidity, a small bite angle to the strip foil 5, and a small lateral component of the rolling force, so its lateral bending tendency is small. In addition, the biting arc length of the working roll on the right side to the foil 5 is longer, which is beneficial for the lubricating medium to be evenly brought into the roll gap, so that the thickness of the oil film in the rolling arc area is more uniform. These factors are beneficial to reduce the arc length fluctuation of the rolling arc along the strip foil width direction, so as to obtain a better rolled strip shape.

To sum up, the small-diameter work rolls are good for thinning, but limited by the difficulty in controlling the rolled strip shape, so the rolling width should not be too large; while the large-diameter work rolls are conducive to the control of the rolled strip shape and are suitable for rolling. Wide, but not suitable for rolling thin. For wide strip foil with a thickness of less than 0.3mm, the diameter of the work roll must be small enough (usually 25-50mm in diameter) to obtain a large amount of rolling reduction, and the shape of the plate at this time will be very difficult to control , which is currently the bottleneck restricting high-precision wide-width strip and foil rolling.

Contents of the invention

In order to overcome the deficiencies in the background technology, the invention discloses a rolling method of a wide metal strip and foil, the purpose of which is to:

1. Make the tension evenly distributed on the cross-section of the foil, and roll the metal strip and foil evenly;

2. Overcome the technical difficulties in the background technology, break the technical bottleneck, and enable the strip and foil to be rolled with wide width and high precision.

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

A rolling method of wide metal strip and foil, using a rolling mill with unequal diameter work rolls, the roll diameter of a certain work roll of the rolling mill is larger than the roll diameter of another work roll; The roll surfaces of the rolls have the same linear speed, and at the entrance or exit side of the roll gap formed by the two work rolls, the metal strip foil is covered on the roll surface of a certain work roll to form a cladding arc. Metal tape foil backing, so that the tension is evenly distributed over the cross-section of the cladding arc.

To further improve the technical solution, the metal strip foil is coated on the roll surface of the work roll with a larger roll diameter to form a cladding arc.

To further improve the technical solution, the cladding arc is obtained by changing the angle at which the metal strip foil enters the roll gap or flows out of the roll gap.

To further improve the technical solution, the wrapping angle of the wrapping arc is α, 0°<α≤90°.

To further improve the technical solution, on the entrance side and the exit side of the roll gap, the metal strip foil is wrapped on the roll surface of the same or different work rolls to form the entrance side cladding arc and the exit side cladding arc.

To further improve the technical solution, the metal strip foil is covered on the roll surface of the work roll with a larger roll diameter.

To further improve the technical solution, the wrapping arc at the entrance side is obtained by changing the angle at which the metal strip foil enters the roll gap, and the wrapping arc at the exit side is obtained by changing the angle at which the metal strip foil flows out of the roll gap.

To further improve the technical solution, the roll diameter of the larger work roll is 1.5-5 times the roll diameter of the smaller work roll.

To further improve the technical solution, before the next pass of rolling, the metal strip and foil are turned over, and then enter the rolling mill for rolling.

To further improve the technical solution, the total number of rolling passes of the metal strip and foil is an even number.

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

It can be seen from Example 1 that the present invention uses a rolling mill with unequal diameter work rolls to roll the strip and foil, which is not only beneficial to the thinning of the strip and foil, but also conducive to obtaining a better plate shape, which breaks through those skilled in the art. Knowledge of rolling mill work rolls. In addition, in the present invention, on the entrance side of the unequal-diameter work roll gap, the tape foil forms a wrapping arc on the work roll, and through the back support of the work roll to the strip foil, the front tension wraps the cross section of the arc on the entry side. Evenly distributed on the top, realized the uniform rolling of the strip and foil, broke through the bottleneck restricting the development of the strip and foil to a wider, thinner, and more ideal shape, and solved the technical problem that has been difficult to solve in the industry for a long time. Therefore, It has great application value and economic value. In addition, the strip foil is not arranged horizontally along the rolling centerline, which breaks the perception in the industry, which is itself creative.

It can be known from Example 2 that the present invention forms a wrapping arc on the roll surface of the work roll with foil on the exit side of the unequal-diameter work roll gap, and realizes the uniform distribution of the back tension on the exit side wrapping arc, Defects such as waves and wrinkles are eliminated in the critical forming stage of strip foil rolling, and then the sheet shape of the strip foil is stabilized in the later stage of rolling forming through the back support of the work rolls, thus obtaining Better shape.

From Embodiment 3 and Embodiment 4, it can be seen that the present invention combines the uniform tension effect of the inlet side cladding arc and the outlet side cladding arc, and overcomes the unequal diameter work on the basis of the beneficial effects of Embodiment 1 and Embodiment 2. The shortcomings brought about by rolling not only solve the problem of curling and deformation of the strip foil, but also unexpectedly solve the problem of different brightness of the upper and lower panels of the strip foil.

What is especially important is that the sliding thinning of the present invention has the effect of extrusion thinning and rolling thinning, and stabilizes the neutral plane at the middle part of the strip foil, thus ensuring the mechanical properties of the strip foil uniformity. The invention breaks through the stringent requirements on the rolling center line in the national standard, truly realizes the stability of the neutral plane by engineering, and solves the technical problems that cannot be solved by the prior art, so it is creative.

For the rolling of extremely thin strip and foil, it is basically zero roll gap or negative roll gap rolling. It is very difficult to reduce its thickness while ensuring the stability of its plate shape, and this is what the present invention needs to solve. core issue. The present invention adopts the rolling scheme of unequal-diameter work rolls, the advantages outweigh the disadvantages, and it is generally beneficial to the thinning of the strip foil, and is also conducive to obtaining a better plate shape, which cannot be achieved by the existing equal-diameter work rolls technical effect. The invention is undoubtedly a technical breakthrough for the rolling of high-precision wide strip foil which has been trapped in a technical bottleneck for a long time.

It is well known that the thinner the strip foil, the more difficult it is to control the shape of the rolled strip. At present, the industry is doing everything possible to break through the limit, but no effective solution has been found yet. The significance of the use of unequal-diameter work rolls in the present invention is that although a part of the thinning of the strip foil is sacrificed and the number of rolling passes (number of reciprocating rolling) is slightly increased, the important thing is to keep the shape of the strip stable. It avoids or reduces the occurrence of rolling defects caused by the increase of the width, which is of great significance for the high-precision rolling of wide-width strip foil.

In addition, the present invention uses unequal-diameter work rolls to roll strip and foil, which breaks through the cognition and prejudice of those skilled in the art on the work rolls of rolling mills, and provides new ideas for the design of rolling mills and the improvement of rolling processes. The rolling method of the invention also overcomes the shortcomings caused by the rolling of unequal-diameter work rolls, and provides a new technical solution for the rolling of wide-width and high-precision strips and foils.

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

Description of drawings

Figure 1 is a schematic diagram of the tension distribution applied to the cross-section of the strip foil under ideal conditions.

Fig. 2 is a schematic diagram of the tension distribution actually applied on the cross-section of the strip foil.

Figure 3 is a typical layout of the current strip and foil rolling.

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

FIG. 5 is a schematic structural diagram of the present invention in Embodiment 1.

Figure 6 is a schematic diagram of a belt drive.

Figure 7 is a force analysis diagram of a certain volume unit on the cladding arc.

Fig. 8 is a force analysis diagram of a certain volume unit when the strip foil is in a state without back support.

Fig. 9 is a force analysis diagram of a certain volume unit when the strip foil is in a back-supported state.

Fig. 10 is a tension distribution diagram in the thickness direction of a volume unit on the cladding arc at the entrance side of the roll gap in Example 1.

Fig. 11 is a flow velocity distribution diagram of the upper and lower layers of the foil in the calendering zone.

FIG. 12 is a schematic structural diagram of the present invention in Embodiment 2.

Fig. 13 is a tension distribution diagram in the thickness direction of a certain volume unit on the wrapping arc at the exit side of the roll gap in Example 2.

Fig. 14 is a schematic structural diagram of the present invention in Embodiment 3.

Fig. 15 is a diagram of the tension distribution in the thickness direction of a volume unit on the cladding arc at the exit side of the roll gap in Example 3.

Fig. 16 is a schematic diagram of the principle of slip thinning.

Fig. 17 is a schematic structural diagram of the present invention in Embodiment 4.

FIG. 18 is a schematic diagram of a partially enlarged structure of FIG. 17 .

In the figure: 1. Upper working roll; 2. Lower working roll; 3. Flattening roll; 4. Lifting roll; 5. Strip foil; 6. Rolling center line; 7. Driving pulley; 8. Belt; 9. volume unit.

Detailed ways

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention. It should be noted that, in the description of the present invention, the terms "front", "rear", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", Terms such as "outside" and other indicated directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, use a specific Azimuth configuration and operation, therefore, should not be construed as limiting the invention.

Example 1:

The invention discloses a rolling method of wide-width metal strip and foil, which is used for rolling copper alloy strip and foil. The final rolling thickness of the copper alloy strip and foil is 0.01mm, and the width is 800mm. The boundary thickness of the strip and the foil is 0.15mm, and the thickness of the copper alloy strip and foil (hereinafter referred to as the strip foil) already belongs to the foil. Due to the high deformation resistance of copper alloy, it is difficult to ensure the flatness of its plate shape.

As shown in Figure 5, a flattening roller 3 is arranged on the entrance side of the roll gap, and the roll surface of the flattening roller 3 is lower than the rolling center line 6. In the roll gap formed by a pair of work rolls, the roll diameter of the upper work roll 1 is 30 mm, the roll diameter of the lower work roll 2 is 60 mm, and the roll diameter of the lower work roll 2 is twice the roll diameter of the upper work roll 1, In order to prevent the upper and lower plate surfaces of the strip foil 5 from being curled due to the difference in rolling line speed, the roll surfaces of the upper work roll 1 and the lower work roll 2 have the same line speed during rolling. Since the strip foil 5 forms a certain angle with the rolling center line 6 before entering the roll gap, the strip foil 5 forms an entrance-side cladding arc on the roll surface of the lower work roll 2, and the cladding arc of the entrance side is clad The angle is α, and α is 30°. Due to the existence of the entrance-side cladding arc, the lower work roll 2 backs up the strip foil 5, and the tension is evenly distributed on the cross-section of the entrance-side cladding arc. The principle is as follows:

As shown in Figure 6, in the transmission of the belt 8, the driving pulley 7 drives the belt 8 to rotate clockwise, point A is the point where the belt 8 enters the driving pulley 7, and point B is the point where the belt 8 leaves the driving pulley 7. point. In the enveloping arc of the entrance side from point A to point B, the friction force generated by the driving pulley 7 on the belt 8 is cumulatively increased, so the tension F2 of the belt 8 at point B is smaller than its tension F1 at point A , and the larger the wrapping angle of the wrapping arc on the entrance side, the greater the difference between F1 and F2, which causes the belt 8 on the side of point B to always be in a slack state, while the belt on the side of point A 8 is always under tension.

For the same reason, as shown in Figure 7, during the rolling process, the strip foil 5 enters the roll gap from the left, the neutral point P is in the calendering arc, and on the left side of the neutral point P, the line on the roll surface of the work roll The speed is greater than the linear velocity of the strip foil 5 entering the roll gap, which produces a speed difference and friction force F3, that is, the lower work roll 2 drives the strip foil 5 to rotate along the wrapping arc on the entrance side, just like the belt 8 drives. In the figure, a volume unit 9 is randomly selected on the inlet side cladding arc. Due to the effect of friction F3, the proximal tension F2 acting on this volume unit 9 is smaller than its distal tension F1. The proximal tension and the distal tension expressed here are Tension is relative to the distance from the roll gap. And for the next volume unit 9 on the right side of the volume unit 9, due to the accumulation of friction F3, the magnitude of the distal tension acting on this volume unit 9 is equal to F2, while the magnitude of the proximal tension is less than F2, and so on. From this, it can be concluded that the friction force F3 increases cumulatively from point A (starting point of the wrapping arc on the inlet side) to point B (end point of the wrapping arc on the inlet side). The proximal tension F2 received decreases gradually from point A to point B.

As shown in Fig. 8, a volume unit 9 is randomly selected on the strip foil 5. Due to the inhomogeneity of tension, the tension on both sides of the volume units 9C and D is greater than the tension on the middle E part, and the E part bulges to form corrugations. When the foil 5 is suspended and tensioned, the tension F2 at the proximal end is equal to the tension F1 at the distal end. At this time, the volume unit 9 shrinks inward in the width direction, and its internal force F4 is negative.

As shown in FIG. 9 , when the volume unit 9 enters the entrance-side cladding arc, the lower work roll 2 exerts a backing force T on it, causing the volume unit 9 to bend and deform. As the proximal tension F2 gradually decreases, the internal force F4 acting on the volume unit 9 in the width direction changes from negative to positive and gradually increases. The increase of the internal force F4 makes the volume unit 9 expand outward along the width direction, just like a loose rubber band widens in the width direction, and then flattens the corrugated portion of the foil 5 . During the flattening process, the proximal tension acting on the two sides of the volume units 9C and D decreases rapidly, and the two sides of C and D extend outward along the width direction, so that the E part in the middle is in contact with the roll surface of the lower work roll 2 , after the E part contacts with the lower work roll 2, the proximal tension in the middle part of the volume unit 9 is correspondingly increased, thereby realizing the uniform distribution of the proximal tension F2 on the cross section of the volume unit 9 . It can be seen from Fig. 6 that the near-end tension F2 located in the rolling area of the roll gap is the front tension of rolling, where the front tension is the smallest, and the front tension distributed on the cross section here is the most uniform. It can also be known that the larger the cladding angle of the cladding arc on the entrance side, the smaller the front tension in the roll gap calendering area, and the more uniform the front tension is distributed.

In rolling, a larger front tension is beneficial to the control of the shape of the plate. The existence of the wrapping arc on the entrance side makes the front tension evenly distributed on the cross-section of the strip foil 5, but part of the front tension is lost, so it is necessary for the coiler or flattening roller 3 to increase the proper front tension of the strip foil 5 to compensate for the loss. During rolling, the tension at the front end of the cladding arc on the entrance side can be increased to 50-60% of the yield strength of the material, and the strip foil 5 can be thinned by making full use of the thinning effect of the tension on the strip foil 5 . For the rolling of the strip foil 5, it is basically seamless rolling. The rolling process of the work roll to the strip foil 5 can be regarded as a repeated thinning and widening process of the strip foil 5. The coiler and the flattening roll 3 can be regarded as the repeated elongation and narrowing process of the strip foil 5, so appropriately increasing the front tension of the strip foil 5 is more conducive to the thinning of the strip foil 5 and the control of the shape of the strip.

It should be noted that the near-end tension F2 changes in a gradient in the thickness direction. As shown in Figure 10, the side of the inlet side cladding arc in contact with the lower work roll 2 has a small tension, and the side away from the lower work roll 2 , its tension is large, which compensates the loss of front tension to a certain extent, especially for thicker strips, the compensation effect is more obvious.

As shown in Figure 11, the shaded part in the figure is the deformation zone. When the strip foil 5 enters the deformation zone of the roll gap, the strip foil 5 is squeezed by the work roll and begins to deform. Due to the existence of the wrapping arc on the entrance side, the deformation of the upper layer of the strip foil 5 is greater than that of the lower layer, and the surface mass of the upper layer is at The linear velocity at the neutral point P is consistent with the linear velocity of the upper work roll 1 roll surface, while the lower plate surface lags behind, and the linear velocity of the particle at point E is consistent with the linear velocity of the lower work roll 2 roll surface, resulting in The outflow velocity of the upper layer of the strip foil 5 is greater than the outflow velocity of the bottom layer of the strip foil 5, and the strip foil 5 is curled to the side of the lower work roll 2, which shows that there is a layer shift phenomenon in the calendering area. The layer migration phenomenon causes the neutral plane of the foil 5 to be biased toward the lower layer, and causes the foil 5 to be curled and deformed. The curling deformation is more obvious on the strip with a larger thickness, but not obvious on the foil with a thickness of less than 0.15mm, and it can be corrected by subsequent processes such as flattening and straightening.

The offset of the neutral plane will cause uneven mechanical properties of the foil. From the background technology, it is difficult to achieve the stability of the neutral plane in actual production. Since it is difficult to achieve, there is no need to follow the national standard The requirements to specify the way the foil enters the roll gap. For some application fields, the requirements for the mechanical properties of the strip foil are not high, such as using copper strip foil for electrical conduction, or for decoration, anti-corrosion, etc., there is no need to overstate the uniformity of the mechanical properties of the strip foil requirements. 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 cognition in the industry, so it is inventive.

It can be seen from Fig. 11 that the roll diameter of the upper work roll 1 is small, and the amount of pressing into the strip foil 5 is large, which is especially beneficial to the thinning of the strip foil 5 and can reduce the total rolling passes. However, the side of the top work roll 1 The tendency to bend is large, which is not conducive to the uniform introduction of lubricating medium into the roll gap. The lateral bending tendency of the lower working roll 2 is small, which is beneficial for the lubricating medium to be evenly brought into the roll gap, and the uniform tension effect of the superimposed covering arc on the strip foil 5, so that the strip foil 5 can obtain a better shape, but the lower The roll diameter of the work roll 2 is large, and the amount of pressing into the strip foil 5 is small, which is not conducive to the thinning of the strip foil 5 . This embodiment combines the advantages of large-diameter work rolls and small-diameter work rolls: Compared with the traditional work rolls with the same diameter as the upper work roll 1, the increase in the roll diameter of the lower work roll 2 is conducive to obtaining a better plate shape; compared with the traditional work roll with the same diameter as the lower work roll 2, the reduction of the roll diameter of the upper work roll 1 has a large amount of pressing into the strip foil 5, which is conducive to the thinning of the strip foil 5. Correspondingly, this embodiment also concentrates the disadvantages of large-diameter work rolls and small-diameter work rolls: Compared with the traditional work rolls with the same diameter as the upper work roll 1, the increase of the roll diameter of the lower work roll 2 is not conducive to Strip foil 5 rolled thin. Compared with the traditional work roll having the same diameter as the lower work roll 2, the reduction of the roll diameter of the upper work roll 1 is not conducive to obtaining a better strip shape. It can be said that the advantages and disadvantages of large roll diameter work rolls and small roll diameter work rolls are a set of irreconcilable contradictions.

The three basic conditions for stable rolling of rolling mills are roll system accuracy, lubrication conditions and tension accuracy. In the case that the accuracy of the roll system and the tension accuracy cannot be further improved, improving the lubrication conditions plays a vital role in stabilizing the shape of the plate. It can be seen from Figure 11 that the lubrication condition is related to the bite angle. At the entrance of the deformation zone, the bite angle of the lower work roll 2 is small, and the wedge-shaped gap formed with the lower surface of the strip foil 5 is more conducive to the entry of lubricating oil, resulting in an oil wedge effect and establishing a stable bearing capacity. In addition, the arc length of the lower calendering is longer, the contact surface is larger, and the arc length fluctuation along the width direction of the strip foil is small, which are conducive to the stability of the plate shape. Compared with the lower work roll 2, although the wedge-shaped gap formed by the upper work roll 1 and the upper surface of the strip foil 5 is not conducive to establishing a stable bearing capacity, the stability of the shape of the lower plate of the strip foil 5 plays a role in restraining the upper surface. It is beneficial to the stability of the plate shape as a whole. To sum up, the main contribution of the small roll diameter work roll is to thin the strip foil, while the main contribution of the large roll diameter work roll is to stabilize the overall shape of the strip foil and reduce the generation of defects such as waves and wrinkles. Generally speaking, although a small amount of thinning is sacrificed, it is beneficial to the stability of the overall plate shape.

For the ultra-thin strip and foil with a thickness of 0.01mm and below, it is basically negative roll gap rolling, and the reduction no longer plays a decisive role. In addition to the rebound in the deformation zone, the use of existing equal-diameter work rolls with larger roll diameters has been unable to effectively reduce the thickness of the strip foil, and only smaller roll diameter work rolls can be used. However, if the existing equal-diameter work rolls with smaller roll diameters are used, the rolling width of the strip and foil cannot be realized, and the rolling width will cause surface defects, which is currently the bottleneck restricting high-precision wide-width strip and foil rolling. 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 order to break through the limit, the industry is doing everything possible, but no effective solution has been found yet. The significance of the use of unequal-diameter work rolls in the present invention is that although a part of the thinning of the strip foil is sacrificed and the number of rolling passes (number of reciprocating rolling) is slightly increased, the important thing is to keep the shape of the strip stable. It avoids or reduces the occurrence of rolling defects caused by the increase of the width, which is of great significance for the high-precision rolling of wide-width strip foil.

It can be seen from Example 1 that the present invention forms the wrapping arc of the strip foil 5 on the lower work roll 2 on the entrance side of the roll gap, and the tension is wrapped on the entrance side by the back support of the strip foil 5 by the bottom work roll 2 . The cross-section of the covered arc is evenly distributed, realizing the uniform rolling of the strip foil 5, breaking through the bottleneck that restricts the development of the strip foil 5 to a wider, thinner, and more ideal shape, and solving the long-standing problem in the industry It is a difficult technical problem, so it has great application value and economic value. The invention adopts a rolling mill with unequal-diameter work rolls to roll the strip and foil, which is not only beneficial to the thinning of the strip and foil, but also beneficial to obtaining a better plate shape.

It should be noted that the wrapping arc of the strip foil 5 on the lower working roll 2 is not limited to the spreader roll 3, but also includes all pre-machine adjustment rolls, such as S rolls, high and low rolls, or combinations thereof. As long as the front adjustment roll closest to the roll gap is adjusted so that the strip foil 5 forms a certain angle with the rolling centerline 6 before entering the roll gap, the entrance side wrapping of the strip foil 5 on the lower working roll 2 can be realized. arc. In this embodiment, the entrance-side cladding arc is formed on the lower work roll 2 , based on the same principle, the entrance-side cladding arc can also be formed on the upper work roll 1 .

Example 2:

As shown in Figure 12, the difference between this embodiment and Embodiment 1 is that the strip foil 5 enters the roll gap horizontally along the rolling center line 6, and a flattening roll 3 is arranged on the exit side of the roll gap, and the flattening roll 3 The roll surface is higher than the rolling centerline 6. The flattening roller 3 post-stretches the strip foil 5 so that the strip foil 5 forms an exit-side cladding arc on the roll surface of the upper working roll 1, and the cladding angle of the exit-side cladding arc is β, and β is also 30°. Due to the existence of the wrapping arc on the exit side, the upper work roll 1 backs up the strip foil 5, and the tension is evenly distributed on the cross section of the wrapping arc on the exit side. The principle is as follows:

As shown in FIG. 13 , the strip foil 5 flowing out from the roll gap is wrapped on the upper work roll 1 to form an outlet-side wrapping arc. Since the linear velocity V of the outflow of the strip foil 5 is greater than the linear velocity of the roll surface of the upper work roll 1, the upper work roll 1 produces a reverse friction force F4 on any volume unit 9 on the wrapping arc on the exit side, and the volume unit 9 also There are proximal tension F5 and distal tension F6 acting on it. According to the description in Example 1, it can be seen that the friction force F4 gradually increases from point M to point N, and similarly, the distal tension F6 also increases accordingly. The distal tension F6 reaches the maximum at point N, and the distal tension F6 here is the back tension. The back tension can not only prevent the strip foil 5 from running off, but also reduce the rolling pressure, which contributes to the high-speed rolling of the strip foil 5 . Since the belt foil 5 flows out of the roll gap, its outflow linear velocity is greater than the linear velocity of the work roll surface, so the belt foil 5 can be understood as a belt, and the upper work roll 1 can be understood as a driven pulley, then the belt foil 5 Drive the upper work roll 1 to rotate, just like a belt drives the driven pulley to rotate, the larger the wrapping arc on the exit side, the greater the transmission torque, thus reducing the torque of the upper work roll 1 and reducing the energy consumption of the main motor .

It is particularly important that after the strip foil 5 flows out from the roll gap, the back tension it receives gradually increases. Based on the mechanism in Example 1, the back tension is the smallest at the exit of the roll gap, and the cross section here The post tension distribution is also the most uniform, which is very important for the control of the foil 5 sheet shape. It can be seen from the discussion in the background technology that only when the tension is evenly distributed on the cross-section of the strip foil can defects such as waves and wrinkles in the plate shape be prevented. However, in the present invention, through the coating of the strip foil 5 on the roll surface of the upper work roll 1, The uniform distribution of tension at the exit of the roll gap is realized, and the generation of defects such as waves and wrinkles is eliminated at the initial stage of strip foil rolling, so that a better plate shape can be obtained. As the volume unit 9 continues to flow out, the distal tension F6 acting on the cross-section of the volume unit 9 gradually increases, and the tendency of uneven tension begins to become obvious. The foil 5 is no longer suspended in the air and shakes, and the plate shape is stabilized during the critical forming period of strip rolling, thereby preventing defects such as waves and wrinkles in the plate shape due to uneven tension.

It can be known from Example 2 that the present invention makes the strip foil 5 form an exit-side cladding arc on the roll surface of the upper work roll 1 on the exit side of the roll gap, and realizes the uniformity of the back tension on the exit-side cladding arc on the exit side. In the early stage of strip and foil rolling, defects such as waves and wrinkles are eliminated, and then through the back support of the upper work roll 1 to the strip foil 5, the strip shape of the strip foil 5 is rolled and formed. It can be stabilized in the later stage, so as to obtain a 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 what makes the strip foil 5 form an outlet-side cladding arc on the upper work roll 1 is not limited to the spreader roll 3, but also includes all post-machine adjustment rolls, such as S rolls, high and low rolls, or combinations thereof . Just adjust the post-machine adjustment roll closest to the roll gap, so that the strip foil 5 forms a certain angle with the rolling center line 6 after coming out of the roll gap, and the strip foil 5 can be formed on the upper work roll 1 to form the exit side. wrapping arc. In this embodiment, the outlet side cladding arc is formed on the upper work roll 1 , based on the same principle, the outlet side cladding arc can also be formed on the lower work roll 2 .

Example 3:

This embodiment can be regarded as a combination of Embodiment 1 and Embodiment 2. As shown in Figure 14, the strip foil 5 forms an inlet-side cladding arc with the lower work roll 2 on the entrance side of the roll gap, and the entrance-side cladding arc The wrapping angle α is 30°; the strip foil 5 forms an exit-side wrapping arc with the upper work roll 1 at the exit side of the roll gap, and the wrapping angle β of the exit-side wrapping arc is also 30°. Due to the existence of the entrance-side cladding arc and the exit-side cladding arc, the lower work roll 2 and the upper work roll 1 respectively produce back support for the strip foil 5 .

The function and influence of the cladding arc on the entrance side in rolling has been explained in Example 1, and the function and influence of the cladding arc on the exit side in rolling has been explained in Example 2, so it will not be repeated here. It is worth noting that, as shown in Figure 13, at the exit side of the roll gap, the linear velocity of the lower layer of the volume unit 9 is greater than that of the upper layer of the volume unit 9, and the friction force F4 acts on the upper surface of the volume unit 9, so that It is concluded that the cladding arc plays a reverse straightening effect on the curling deformation of the strip foil 5, which to a certain extent eliminates the effect of layer shift on the curling of the strip foil 5.

In the production of the strip foil 5, the strip foil 5 needs to be repeatedly rolled for multiple passes. Due to the layer shift phenomenon, after each pass of rolling, the strip foil 5 will be unidirectionally curled and deformed. Although the upper work roll 1 can reversely straighten the curling deformation, it is not enough to completely eliminate the curling deformation, so the rolling method needs to be improved.

Combining with Figures 11, 14, and 15, it can be seen that after the strip foil 5 is rolled from left to right for the first pass, the outflow velocity of the upper layer of the strip foil 5 is greater than the outflow velocity of the lower layer of the strip foil 5, and the strip foil 5 goes down to the work roll 2 curled on one side. After the strip foil 5 is rolled from right to left for the second pass, the outflow speed of the upper layer of the strip foil 5 is lower than the outflow velocity of the lower layer of the strip foil 5, and the strip foil 5 is curled up to the side of the work roll 1, thus making the first pass The curl of the next rolling is reversely corrected, and so on. It can be seen from the above that setting the total rolling passes of the strip foil 5 to an even number can eliminate the curling deformation of the strip foil 5 to the greatest extent.

It is especially important that after the first pass of rolling, the neutral plane of the strip foil 5 deviates from one side, then the second pass of rolling reversely corrects the deviated neutral plane. After even-numbered rolling, the neutral plane is stabilized at the middle layer of the strip foil 5, thereby ensuring the uniformity of the mechanical properties of the strip foil 5. Through this method, the stringent requirements on the rolling center line 6 in the national standard are circumvented, and the stability of the neutral plane of the strip foil 5 is truly engineered, which solves the problem that cannot be solved in the prior art and in Example 1. technical problems.

As shown in Figure 4, in traditional rolling, there is no speed difference in the speed of the strip foil 5 flowing out of the roll gap, and its thinning process can be regarded as extrusion, just like squeezing toothpaste. In the present invention, there is a difference in the speed at which the foil 5 flows out from the roll gap, and the thinning process of the foil 5 is more like the reverse rolling of the upper and lower layers of the foil 5, just like rolling the dough with a rolling pin cake. As shown in Figure 16, in the process of repeated rolling and pressing, the upper and lower layers of the strip foil 5 are not only squeezed by the roll gap, but also subjected to the relative stretching force, so that the upper and lower layers of the strip foil 5 are squeezed. Slip, eventually reducing the thickness. This kind of sliding thinning has the effect of extrusion thinning and rolling thinning. Compared with the traditional extrusion thinning, the shape of the plate is better and it is easier to control the shape of the plate.

It can be seen from Example 3 that the present invention better solves the problem of curling and deformation of the strip foil 5, and it is especially important that the sliding thinning of the present invention not only has the effect of extrusion thinning, but also has the effect of rolling thinning , and stabilize the neutral plane at the middle layer of the foil 5, thereby ensuring the uniformity of the mechanical properties of the foil 5. The invention breaks through the strict requirements on the rolling center line in the national standard, truly realizes the stability of the neutral plane by engineering, and solves the technical problems that cannot be solved by the prior art.

In Example 3, the wrapping arc at the exit side reduces the torque of the upper work roll 1, but the wrapping arc at the entrance side increases the torque of the lower work roll 2, resulting in a difference in the driving torque of the upper and lower work rolls, which will increase The overall energy consumption of a large rolling mill. To this end, continue to improve the technical solution:

Example 4:

As shown in FIG. 17 , the present embodiment is different from Embodiment 3 in that both the entrance-side cladding arc and the exit-side cladding arc are formed on the lower work roll 2 . It can be seen from Fig. 17 that the wrapping arc on the entrance side increases the torque of the lower work roll 2, while the wrapping arc on the exit side reduces the torque of the lower work roll 2. Therefore, the driving torque applied to the lower work roll 2 is generally not Change.

As shown in Figure 18, since the roll diameter of the upper work roll 1 is smaller than the roll diameter of the lower work roll 2, both the entrance-side cladding arc and the exit-side cladding arc are formed on the lower work roll 2, so the upper work roll 1 is opposite to the strip foil The thinning effect of 5 is the largest. However, this embodiment has the disadvantage that, due to superposition effects, the unidirectional curling deformation of the strip foil 5 is greater than in the above-described embodiments. In order to overcome this shortcoming, the solution is to turn over the strip foil 5 before each pass of rolling, and then send the strip foil 5 into the roll gap for rolling. In this way, the curling deformation of the strip foil 5 generated during the previous rolling pass can be eliminated by turning over rolling. The difference between flip rolling and existing rolling is that in two adjacent passes of rolling, the surfaces of the foils 5 rolled by the upper work roll 1 and the lower work roll 2 are different. In order to ensure the consistency of the properties of the upper and lower surfaces of the strip foil 5, similarly, the total number of rolling passes of the strip foil 5 is set to an even number.

After adopting the above method, on the one hand, the torque of the upper and lower work rolls is balanced, and on the other hand, the curling deformation of the strip foil 5 during rolling is eliminated. It is particularly worth noting that due to the flip-rolling, the contact length and force between the upper and lower surfaces of the strip foil 5 and the upper and lower work rolls are the same, thus unexpectedly solving the problem of different brightness of the upper and lower surfaces of the strip foil 5 , which is also a problem that cannot be solved in the above-mentioned embodiment.

It should be noted that the above embodiments all take the rolling of a strip with a thickness of 0.01mm as an example, which does not prevent the present invention from being able to roll a thicker strip, and its principle and function are the same.

The parts not described in detail are prior art. Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (7)

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, 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 formed by the two working rolls to form an inlet side coating arc and an outlet side coating arc, and tension is uniformly distributed on the cross section of the coating arc by back supporting the metal strip foils through the working rolls.

2. 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.

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

4. A method of rolling a wide width metal strip foil as claimed in claim 1, 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.

5. 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.

6. A method of rolling a wide width metal strip foil as claimed in any one of claims 1 to 5, wherein: before the next rolling, the metal strip foil is turned over and then enters a rolling mill for rolling.

7. The method of rolling a wide metal strip foil as claimed in claim 6, wherein: the total rolling passes of the metal strip foil are even number of times.

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