CN116371917A - Cold rolling method of strip steel and strip steel - Google Patents

Abstract

The application discloses a cold rolling method of strip steel and strip steel, wherein the cold rolling method comprises the following steps: providing strip steel to be processed; and (3) putting the strip steel to be processed into a single-stand rolling mill, wherein the target plate shape is taken as a W plate shape control single-stand rolling mill with a tiny edge wave at the edge and a tiny middle wave at the middle, and carrying out n-pass rolling on the strip steel to be processed in a reciprocating manner to obtain the strip steel, wherein n is a positive integer. According to the cold rolling method of the strip steel and the strip steel, the diagonal stripes of the strip steel rolled by the single-stand rolling mill can be effectively reduced.

Description

Cold rolling method of strip steel and strip steel

technical field

The application belongs to the technical field of steel rolling, and in particular relates to a strip steel cold rolling method and the strip steel.

Background technique

After the steel strip is rolled by a cold rolling mill, there are mostly diagonal stripes, especially for the strip rolled by a single-stand rolling mill, the situation of the diagonal stripes is particularly serious. The uneven transverse tension of the strip at the roll gap of the single stand causes the uneven longitudinal elongation of the metal in the cross-section of the strip, and the interaction of internal stress occurs between the longitudinal strips. When the internal stress exceeds the critical stress value of the strip warpage It will cause the strip to warp. After the strip steel of this strip element is warped, the tension becomes smaller, and the tension of the adjacent strip element becomes larger, and new warpage occurs, which leads to the trend of increasing or decreasing longitudinal length of the adjacent internal strip elements of the strip steel, thus Diagonal stripes are produced. Severe oblique stripe defects cannot be eliminated in subsequent processes, affecting use.

Contents of the invention

Embodiments of the present application provide a strip steel cold rolling method and the strip steel, which can effectively reduce oblique stripes of the steel strip rolled by a single-stand rolling mill.

The embodiment of the first aspect of the present application provides a method for cold rolling a steel strip, including:

Provide strip steel to be processed;

The strip to be processed is put into a single-stand rolling mill, and the single-stand rolling mill is controlled by the W-shaped plate shape with the target shape as the edge micro-wave and the middle part is micro-wave, and the strip to be processed is rolled reciprocatingly for n passes to prepare the strip , n is a positive integer.

According to the embodiment of the first aspect of the present application, the side waves of the W plate shape are 3I-6I, the middle waves are 8I-15I, and the gain value is 20-60.

According to any one of the above-mentioned implementations of the first aspect of the present application, the single-stand rolling mill with W plate shape control with the target plate shape as the edge micro-wave and the middle micro-medium wave performs n-pass rolling of the strip to be processed reciprocatingly, including:

Calculate the target bending value, target roll shifting value and target inclination of the work roll of the single-stand rolling mill according to the roll shape and target shape of the work roll of the single-stand rolling mill;

The work rolls of the single-stand rolling mill are controlled according to the target roll bending value, the target roll shifting value and the target inclination amount.

According to any one of the aforementioned embodiments of the first aspect of the present application, the unit tension at the exit of each rolling pass of the single-stand rolling mill is 17-24 kg/mm ² .

According to any one of the above-mentioned implementations of the first aspect of the present application, the _exit unit tension T _i of the i-th pass of the single-stand rolling mill is greater than or equal to the exit unit tension T i of the (i-1) pass of the single-stand rolling mill ₁ , where i is a positive integer, 2≤i≤n.

According to any one of the aforementioned embodiments of the first aspect of the present application, the rolling force of each pass of the single-stand rolling mill is 6000 kN˜12000 kN.

According to any one of the aforementioned embodiments of the first aspect of the present application, the rolling force F _{i of} the i-th pass of the single-stand rolling mill is less than or equal to the rolling force F i of the (i-1) pass of the single-stand rolling mill ₁ , where i is a positive integer, 2≤i≤n.

According to any one of the aforementioned embodiments of the first aspect of the present application, the roughness of the work rolls of the single-stand rolling mill is 0.5um-1.0um.

According to any one of the above-mentioned implementations of the first aspect of the present application, providing the steel strip to be processed includes:

Provide blanks to be processed;

Hot-rolling and pickling are performed sequentially on the billet to be processed to obtain strip steel to be processed.

The embodiment of the second aspect of the present application provides a steel strip prepared by the cold rolling method of any one of the aforementioned first aspects.

The cold-rolling method of the steel strip of the embodiment of the present application, the steel strip to be processed is put into the single-stand rolling mill, and the single-stand rolling mill is controlled with the target plate shape as the W plate shape of the edge part micro-edge wave and the middle part micro-medium wave Reciprocating rolling is carried out n times to prepare strip steel. By setting the target strip shape of the strip to a W strip with slightly corrugated edges and slightly medium corrugations in the middle, the transverse tension distribution of the strip can be made more uniform, and the oblique stripes of the strip rolled by a single-stand rolling mill can be effectively reduced .

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the embodiments of the present application. Additional figures can be derived from these figures.

Fig. 1 is a schematic flow chart of a strip cold rolling method according to an embodiment of the first aspect of the present application;

Fig. 2 is a schematic diagram of the W-strip shape of the middle micro-edge corrugation and the central micro-medium corrugation of a strip cold-rolling method according to the embodiment of the first aspect of the present application.

Detailed ways

The characteristics and exemplary embodiments of various aspects of the application will be described in detail below. In order to make the purpose, technical solution and advantages of the application clearer, the application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only intended to explain the present application rather than limit the present application. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application. In the drawings and the following description, at least part of the known structures and techniques are not shown in order to avoid misunderstanding of the present application. Application creates unnecessary obscurity; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described hereinafter may be combined in any suitable manner in one or more embodiments.

It should be noted that, in this article, unless otherwise stated, "plurality" means more than two; the terms "upper", "lower", "left", "right", "inner", "outer", etc. The indicated orientation or positional relationship is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the application . Furthermore, relational terms such as first and second, etc., are used merely to distinguish one entity or operation from another without necessarily requiring or implying that any such actual relationship between the entities or operations exists. relationship or sequence. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the statement "comprising..." does not exclude the presence of additional same elements in the process, method, article or device comprising said element.

The orientation words appearing in the following description are the directions shown in the figure, and do not limit the specific structure of the embodiment of the present application. In the description of this application, it should also be noted that unless otherwise specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or Connected integrally; either directly or indirectly. It should be understood that when describing the structure of a component, when a layer or a region is referred to as being "on" or "over" another layer or another region, it may mean being directly on another layer or another region, or Other layers or regions are also included between it and another layer or another region. And, if the part is turned over, the layer, one region, will be "below" or "beneath" the other layer, another region. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

After the steel strip is rolled by a cold rolling mill, there are mostly diagonal stripes, especially for the strip rolled by a single-stand rolling mill, the situation of the diagonal stripes is particularly serious. The uneven transverse tension of the strip at the roll gap of the single stand causes the uneven longitudinal elongation of the metal in the cross-section of the strip, and the interaction of internal stress occurs between the longitudinal strips. When the internal stress exceeds the critical stress value of the strip warpage It will cause the strip to warp. After the strip steel of this strip element is warped, the tension becomes smaller, and the tension of the adjacent strip element becomes larger, and new warpage occurs, which leads to the trend of increasing or decreasing longitudinal length of the adjacent internal strip elements of the strip steel, thus Diagonal stripes are produced. Severe oblique stripe defects cannot be eliminated in subsequent processes, affecting use.

In order to solve the above problems, the embodiments of the present application provide a strip steel cold rolling method and the strip steel. Embodiments of the present application will be described below with reference to the accompanying drawings.

Please refer to Fig. 1, the embodiment of the first aspect of the present application provides a cold rolling method for steel strip, including:

S1. Provide strip steel to be processed;

S2, put the steel strip to be processed into the single-stand rolling mill, and take the target plate shape as the W plate shape control single-stand rolling mill with the micro-edge wave at the edge and the micro-medium wave in the middle, and carry out n-pass rolling on the strip steel to be processed reciprocatingly, and prepare Strip steel, n is a positive integer.

Among them, compared with the cold tandem mill, the single-stand rolling mill has only one unit, and the rolling direction is reversible. The single-stand rolling mill has a small footprint, a small investment, a small diameter of the work rolls, and high rolling precision. Optionally, rolling is carried out by using an eighteen-high single-stand rolling mill, and the diameter of the work rolls of the eighteen-high single-stand rolling mill is 140 mm to 170 mm. The multi-rolling of the single-stand rolling mill is realized by reciprocating multiple rolling. Exemplarily, the strip rolled in the first pass moves along the first direction, and then the strip rolled in the second pass moves along the opposite direction of the first direction. direction, the third rolling strip is rolled along the first direction again, and so on to complete the reciprocating multiple rolling. The shape of the strip is the degree of warping of the strip, and its essence is the distribution of residual stress inside the strip.

Please refer to Fig. 2. Fig. 2 is a schematic diagram of a W plate shape with small side waves in the part and micro-medium waves in the middle. The abscissa is the width D of the strip, and the ordinate is the I value of the plate shape. The W plate shape is a plate shape curve with slight waves on the sides and slightly medium waves in the middle. When the edge is double-sided, the transverse tension of the strip is more evenly distributed, which can effectively reduce the oblique stripes. There is a certain middle wave in the middle, the extension of the middle is larger than that of the side, and the small extension of the side is beneficial to improve the horizontal difference between the same plate. The W plate shape can realize double-sided wave rolling, and at the same time ensure a certain middle wave, which can improve the difference between the same plate.

The cold-rolling method of the steel strip of the embodiment of the present application, the steel strip to be processed is put into the single-stand rolling mill, and the single-stand rolling mill is controlled with the target plate shape as the W plate shape of the edge part micro-edge wave and the middle part micro-medium wave Reciprocating rolling is carried out n times to prepare strip steel. By setting the target strip shape of the strip to a W strip with slightly corrugated edges and slightly medium corrugations in the middle, the transverse tension distribution of the strip can be made more uniform, and the oblique stripes of the strip rolled by a single-stand rolling mill can be effectively reduced .

In some optional embodiments, the side wave of the W board shape is 3I-6I, the middle wave is 8I-15I, and the gain value is 20-60.

Among them, the plate shape I=(ΔL/L)×10 ⁵ , I is the plate shape of the strip steel, expressed in I unit; ΔL is the longitudinal extension difference of the strip steel, the unit is mm; L is the strip steel strip reference point Length, in mm. The gain value reflects the severity of the plate bending.

In these optional embodiments, the side corrugations of the W plate shape are set to 3I-6I, the middle corrugations are 8I-15I, and the gain value is 20-60, which can better reduce the oblique stripes of the steel strip.

In some optional embodiments, S2 includes:

S201. Calculate the target bending value, the target roll shifting value and the target inclination amount of the working rolls of the single-stand rolling mill according to the roll profile and target shape of the working rolls of the single-stand rolling mill;

S202. Control the work rolls of the single-stand rolling mill according to the target roll bending value, the target roll shifting value and the target inclination amount.

Optionally, one side of the intermediate roll in the work roll of the single-stand rolling mill adopts a two-stage tapered roll profile with different slopes. The roll shape is beneficial to reduce the edge compression of the strip, and at the same time the edge extension is also reduced, making it easier to produce waves.

Wherein, the roll shifting value is the movement amount of the work roll along its axial direction. The roll shifting of the work roll can adjust the plate shape to a certain extent, and can make the work roll wear evenly and reduce the excessive deflection of the work roll. The shifting of the work rolls is divided into positive shifting and negative shifting. Positive shifting means that the upper work roll moves to the driving side, and the lower work roll moves to the operating side, which increases the curvature of the work rolls and can effectively reduce edge waves; negative shifting It means that the upper work roll moves to the operating side, and the lower work roll moves to the driving side, so that the curvature of the roll is reduced and the possibility of edge waves is increased. Roll bending is the bending amount of the work roll, which can ensure the flatness of the strip and also affect the shape of the strip. Roll bending is divided into positive bending and negative bending. The so-called positive bending means that the upper work roll increases the bending force upward, and the lower work roll increases the bending force downward. The bending degree of the work roll increases and the rolling force decreases. Reduce the thickness of the middle part of the strip, and the thickness of the edge will increase relatively; while the negative bending means that the upper work roll increases the bending force downward, and the lower work roll increases the bending force upward, the bending degree of the work roll decreases, and the rolling force increases , so that the thickness of the middle of the strip can be increased, and the thickness of the edge is relatively reduced. The inclination of the work rolls can also affect the shape of the strip to a certain extent. Both the bending and shifting values of the work rolls can be driven by oil cylinders.

In these optional embodiments, during rolling, the target roll bending value, the target roll shifting value and the target inclination amount are calculated according to the roll shape of the work roll of the single-stand rolling mill and the target strip shape of the strip, and the target roll bending value is calculated according to the target roll bending value. , the target roll shifting value and the target inclination amount control the work rolls of the single-stand rolling mill to complete the rolling, better control the shape of the strip, and thus reduce the oblique stripes.

In some optional embodiments, the outlet unit tension of each rolling pass of the single-stand rolling mill is 17-24 kg/mm ² . Increasing the outlet unit tension during the rolling process can help to improve the extension of the strip in the rolling longitudinal direction, on the other hand, it can reduce the rolling force, weaken the fixed clamping effect of the work roll on the strip at the roll gap and the effect on the roll gap. Limit the lateral deformation of the strip metal, thereby weakening and eliminating diagonal stripes. However, the tension of the export unit is too large, and the strip steel has the risk of edge cracking or strip breaking, so it is not easy to be too large. In this embodiment, the outlet unit tension of each pass of the single-stand rolling mill is set at 17-24kg/mm ² , which ensures that the strip does not produce edge cracks or broken strips, and effectively reduces the oblique stripes of the strip.

It should be understood that the exit of the single-stand rolling mill is the port where the steel strip to be processed comes out last. Since the rolling of the strip to be processed in the single-stand rolling mill is reciprocating rolling, the entrance and exit of the single-stand rolling mill are relative. Exemplarily, the single-stand rolling mill includes a first port and a second port, and the strip to be processed in the first pass moves along the direction from the first port to the second port, so the first port is the entrance of the single-stand rolling mill, and the first port is the entrance of the single-stand rolling mill. The second port is the exit of the single-stand rolling mill, and the strip to be processed in the second pass moves along the direction of the second port to the first port, so at this time the second port is the entrance of the single-stand rolling mill, and the first port is the single-stand Mill export.

In some optional embodiments, the exit unit tension T _i of the i-th pass of the single-stand rolling mill is greater than or equal to the exit unit tension T i- ₁ of the (i-1) pass of the single-stand rolling mill, wherein, i is a positive integer, 2≤i≤n.

In these optional embodiments, with the increase of the rolling passes, the strength of the strip is greater and greater, and the outlet unit tension of the single-stand rolling mill is gradually increased, which is more conducive to the longitudinal extension of the Daishan strip. Thereby reducing the diagonal stripes of the strip.

In some optional embodiments, the rolling force of each pass of the single-stand rolling mill is 6000kN-12000kN.

In these optional embodiments, the single-stand rolling mill rolls the strip with a rolling force of 6000kN-12000kN, compared with the cold tandem rolling mill, the rolling force is reduced by 20%-35%, which can weaken the work roll at the roll gap. The fixed clamping effect on the strip and the restriction on the lateral deformation of the strip metal at the roll gap, thereby weakening and eliminating diagonal stripes.

In some optional embodiments, the rolling force F _i of the i-th pass of the single-stand rolling mill is less than or equal to the rolling force F i _- 1 of the (i-1) pass of the single-stand rolling mill, wherein, i is a positive integer, 2≤i≤n. With the increase of rolling passes, the reduction rate of the single-stand rolling mill decreases gradually, but the deformation resistance also increases. From the second pass, the rolling force of each pass is less than or equal to that of the previous pass. It is more conducive to weakening and eliminating diagonal stripes.

In some optional embodiments, the roughness of the work rolls of the single-stand rolling mill is 0.5um-1.0um. The smaller the surface roughness of the work roll, the higher the surface finish. During rolling, the friction coefficient between the work roll and the strip in the contact area between the work roll and the strip is smaller, which is more conducive to the lateral flow of metal in the roll gap. It can improve the problem of uneven longitudinal elongation of the metal strip cross section, thereby improving oblique stripes. However, the roughness of the work rolls is too small, which will easily cause the strip to slip during the rolling process.

In these optional embodiments, the surface roughness of the work rolls is 0.5um-1.0um, which can not only ensure that the strip slips during the rolling process, but also facilitate the lateral flow of metal in the roll gap, thereby reducing or eliminating skew. stripe.

In some optional embodiments, S1 includes:

S101, providing a blank to be processed;

S102, performing hot rolling and pickling on the blank to be processed in sequence to obtain a steel strip to be processed.

Among them, the billet to be processed can be a cast slab, and the billet to be processed is heated by a heating furnace and then hot-rolled. Hot rolling can improve the processing performance of metals and alloys, that is, the coarse grains in the casting state are broken, significantly Cracks heal, reduce or eliminate casting defects, transform the as-cast structure into deformed structure, and improve the processing performance of the alloy. There will be iron scale on the surface of the hot-rolled slab, so the slab needs to be pickled in a pickling tank to remove the iron oxide scale on the surface, thereby improving the surface quality of the strip steel obtained after rolling.

In some optional embodiments, the cold rolling method also includes:

S3, continuous annealing and smoothing treatment. Continuous annealing is a production method in which the strip steel continuously passes through the annealing furnace, and the strip steel is directly coiled without stopping. Continuous annealing can eliminate work hardening and residual internal stress, and obtain the structure and properties that meet the customer's processing requirements. Smoothing treatment can further eliminate the slight diagonal stripes produced after rolling.

In order to further illustrate the cold rolling method provided by the embodiment of the present application, the following examples and comparative examples are provided.

Example 1:

Provide grade A oriented silicon steel steel strip to be processed. The thickness of the steel strip to be processed is 0.6mm and the width is 1080mm. Put the strip to be processed into a single-stand rolling mill. Zhonglang’s single-stand rolling mill with W shape control conducts 5 reciprocating rolling passes on the strip to be processed. The side wave of the W shape is 8I, the middle wave is 10I, and the gain value is 30. The export unit tension of the first rolling single-stand rolling mill is 17kg/mm ² , the export unit tension of the second rolling single-stand rolling mill is 19kg/mm ² , and the third-pass rolling single-stand rolling mill export unit The tension is 20kg/mm ² , the exit unit tension of the single-stand rolling mill for the fourth pass is 21kg/mm ² , and the exit unit tension of the single-stand rolling mill for the fifth pass is 22kg/mm ² . The surface roughness of the work rolls of the single-stand rolling mill is 0.9um.

After being rolled by a single-stand rolling mill, the oblique stripes of the strip are very slight visually and have no hand feeling, which can be eliminated after continuous annealing and smoothing.

Example 2:

Provide B grade medium-high carbon steel strip to be processed. The thickness of the steel strip to be processed is 1.2mm and the width is 1250mm. Zhonglang’s single-stand rolling mill with W shape control conducts 3-pass rolling of the strip to be processed. The side wave of the W shape is 5I, the middle wave is 15I, and the gain value is 40. The outlet unit tension of the single-stand rolling mill in the first pass is 21kg/mm ² , the export unit tension of the second-pass rolling single-stand mill is 22kg/mm ² , and the export unit of the third pass rolling single-stand mill The tension is 23 kg/mm ² . The surface roughness of the work rolls of the single-stand rolling mill is 0.7um.

After being rolled by a single-stand rolling mill, the oblique stripes of the strip are very slight visually and have no hand feeling, which can be eliminated after continuous annealing and smoothing.

Comparative example 1:

Provide C grade medium-high carbon steel strip to be processed. The thickness of the steel strip to be processed is 1.0mm and the width is 1280mm. The strip to be processed is reciprocally rolled for 3 passes, and the middle wave of the plate shape is 18I. The export unit tension of the first rolling single-stand rolling mill is 13kg/mm ² , the export unit tension of the second rolling single-stand rolling mill is 14kg/mm ² , and the third-pass rolling single-stand rolling mill export unit The tension is 15 kg/mm ² . The surface roughness of the work rolls of the single-stand rolling mill is 1.0um.

In this comparative example, the target board shape is not a W board shape with slightly corrugated edges and slightly medium corrugated middle, and the outlet unit tension is less than 17kg/mm ² . After being rolled by a single-stand rolling mill, the oblique stripes of the strip steel are obvious visually and have a strong hand feeling, which cannot be eliminated after continuous annealing and smoothing.

It can be seen from the above two examples and a comparative example that the cold rolling method provided in the example of the present application can effectively reduce or eliminate oblique stripes.

The embodiment of the second aspect of the present application provides a steel strip prepared by the cold rolling method of any one of the aforementioned first aspects. Optionally, the steel strip has a thickness of 0.3mm-2.5mm and a width of 900mm-1450mm.

According to the above embodiments of the present application, these embodiments do not exhaustively describe all details, nor limit the invention to only specific embodiments. Obviously many modifications and variations are possible in light of the above description. This description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can make good use of the present application and its modifications based on the present application. It should be understood that the protection scope of the present application is not limited thereto, and any person familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the application, and these modifications or replacements should cover all Within the protection scope of this application.

Claims (10)

1. A cold rolling method of strip steel, applied to a Shan Jijia rolling mill, comprising:

providing strip steel to be processed;

and placing the strip steel to be processed into a single-stand rolling mill, controlling the single-stand rolling mill to perform n-pass rolling on the strip steel to be processed by taking the target plate shape as the W plate shape of the micro-edge wave at the edge and the micro-center wave at the middle, and preparing the strip steel, wherein n is a positive integer.

2. The cold rolling method according to claim 1, wherein the side waves of the W plate shape are 3I to 6I, the middle waves are 8I to 15I, and the gain value is 20 to 60.

3. The cold rolling method according to claim 2, wherein the W-shape with the target shape as the side micro-edge wave and the middle micro-center wave controls the single-stand rolling mill to reciprocate the strip steel to be processed for n-pass rolling, comprising:

calculating a target roll bending value, a target roll shifting value and a target inclination amount of the working roll of the single-stand rolling mill according to the roll shape and the target plate shape of the working roll of the single-stand rolling mill;

and controlling the working rolls of the single-frame rolling mill according to the target roll bending value, the target roll shifting value and the target inclination amount.

4. The cold rolling method according to claim 1, wherein the outlet unit tension per pass of the single stand mill is 17-24 kg/mm ² 。

5. The cold rolling method according to claim 4, wherein the outlet unit tension T of the i-th pass rolling of the single stand mill _i The outlet unit tension T of the i-1 th pass rolling of the single-frame rolling mill is greater than or equal to _i-1 Wherein i is a positive integer, and i is more than or equal to 2 and less than or equal to n.

6. The cold rolling method according to claim 1, wherein the rolling force per one pass of the single stand mill is 6000kN to 12000kN.

7. The cold rolling method according to claim 6, wherein the rolling force F of the i-th pass rolling of the single stand mill _i A rolling force F less than or equal to the i-1 th pass rolling of the single-stand rolling mill _i-1 Wherein i is a positive integer, and i is more than or equal to 2 and less than or equal to n.

8. The cold rolling method according to claim 1, wherein the roughness of the work rolls of the single stand mill is 0.5um to 1.0um.

9. The cold rolling method according to claim 1, wherein the providing the strip steel to be processed comprises:

providing a blank to be processed;

and carrying out hot rolling and acid washing on the blank to be processed in sequence to obtain the strip steel to be processed.

10. A strip steel produced by the cold rolling process of any one of claims 1 to 9.

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