JP2016172269A - Steel strip cold-rolling equipment and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide steel strip cold-rolling equipment and a manufacturing method capable of precisely preventing the occurrence of wrinkles of an ultrathin steel strip when finishing hot-rolled steel strip into the ultrathin steel strip (foil) according to cold rolling.SOLUTION: Steel strip cold-rolling equipment includes: a cold-rolling machine which performs cold rolling of a steel strip; a tension reel which winds the cold-rolled steel strip; and a wrinkle suppressing roll which is provided between the cold rolling machine and the tension reel and prevents wrinkles of the steel strip form occurring. Therein, the wrinkle suppressing roll has a wrinkle suppressing roll main body which comes into contact with the steel strip and a roll deflection shape changing mechanism which changes a roll deflection shape in a width direction of the wrinkle suppressing roll main body.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a steel strip cold rolling facility and a manufacturing method, and more particularly, to a steel strip cold rolling facility and a manufacturing method for finishing a hot-rolled steel strip into a very thin steel strip (foil) by cold rolling.

  In general, ultra-thin steel strips such as stainless steel foil are rolled into a hot-rolled steel strip having a thickness of about 2.0 to 5.0 mm using a hot rolling mill, and then the hot-rolled steel strip is cold-rolled. It is manufactured by rolling to a target plate thickness (for example, 0.1 mm or less).

  In cold rolling for producing such an ultrathin steel strip, a multistage reverse rolling mill such as a Sendzimir mill or a cluster mill with a small roll diameter is usually used.

  FIG. 1 shows an equipment configuration of a general Sendzimir rolling mill. A steel strip 4 unwound from a coil 3 mounted on a tension reel 2a provided on one side of the rolling mill 1 is rolled and passed through a deflector roll 5a, and subsequently a deflector roll provided on the opposite side. An operation to be wound around the tension reel 2b is performed through 5b, and one rolling sheet is completed. If rolling to the target sheet thickness cannot be performed due to rolling load restrictions of the equipment, the rolling direction is reversed and the rolling operation is performed again.

At this time, a tension of about 10 to 70 kgf / mm ² is applied to the steel strip 4 as a unit tension. Acts. The greater the compressive stress, that is, the higher the tension, the thinner the steel strip 4 is, and the wider the plate width, the more easily the steel strip 4 buckles in the plate width direction.

  That is, in general, the rolled steel strip 4 has a thinner plate thickness at the end of the plate width than the plate thickness at the center of the plate width. Therefore, when the steel strip 4 is wound around the tension reel 2b, As the take-up weight (the number of windings) increases, the outer diameter of the center of the plate width of the coil becomes larger than the outer diameter of the end portion of the plate width. Therefore, in the steel strip 4 immediately before being wound around the coil, a large tension acts near the center of the plate width where the outer diameter of the coil is large, and a tension distribution as shown in FIG. 2 is generated. At this time, the tension acting on the center of the plate width increases as the number of turns increases, and when the compressive stress in the plate width direction acting on the tension is equal to or greater than the buckling stress of the steel strip 4, the steel strip 4 extends in the plate width direction. Will buckle and wrinkles will occur at the center of the plate width. When wrinkles occur, it is necessary to cut the coil and perform rolling again from a state where the coil diameter is small again, which greatly deteriorates productivity and yield.

  In addition, in the rolled steel strip 4, when the plate thickness at the plate width end is thicker than the plate thickness at the plate width center, the coil has an outer diameter at the plate width end than the outer diameter at the plate width center. There is a possibility that the tension applied to the end portion of the plate width increases and the wrinkles due to buckling occur at the end portion of the plate width. Here, wrinkles due to buckling of the end portions of the plate width are included in the wrinkles.

  As a technique for preventing the occurrence of wrinkles as described above, for example, there are methods disclosed in Patent Documents 1 to 3.

JP-A-4-294813 JP-A-6-63606 JP 2001-239303 A

  However, the methods disclosed in Patent Documents 1 to 3 described above are insufficient to completely suppress the generation of wrinkles particularly in rolling an ultrathin steel strip having a wide width and a thickness of 0.1 mm or less.

  That is, in the method disclosed in Patent Document 1, in order to prevent buckling that occurs in the ultrathin steel strip in the threading plate, the cross-section arc shape in which the diameter is sequentially increased from the width center toward the end portion. This is a method of preventing wrinkles from occurring due to the effect of reducing the tension acting on the central part of the steel strip and the restraining effect due to contact with the roll by pushing a roll having a concave shape (concave roll).

  However, in this method, the width direction change (roll axis direction change) of the roll diameter of the concave roll depends on the plate crown of the steel strip (= (plate thickness at the center of the plate width) − (plate thickness at the plate width end)). There is no problem if the concave roll can be set well so as to reduce the generated tension distribution, but if the setting of the concave roll is deviated from the plate crown of the steel strip, a sufficient effect can be obtained. Can not. Actually, the sheet crown of the hot-rolled steel strip, which is a rolling material for cold rolling, varies greatly depending on the hot-rolling conditions. Therefore, in the method disclosed in Patent Document 1, the variation of the sheet crown must be handled. I can't.

  In addition, the method disclosed in Patent Document 2 reduces the plate crown of the hot-rolled steel strip that causes the tension distribution during coil winding, and reduces the plate crown ratio (= (plate crown) / (plate width center). Is controlled to a range of 0.1 to 0.7% to suppress the generation of wrinkles.

  However, the sheet crown of the hot-rolled steel strip generally fluctuates greatly depending on the hot-rolling conditions, and when aiming at a small sheet-crown ratio, there is a problem that the sheet-passability in the hot-rolling finish rolling mill deteriorates. For this reason, it is difficult to practically and stably control the sheet crown ratio of the entire hot-rolled steel strip within the range of 0.1 to 0.7%.

  In addition, the method disclosed in Patent Document 3 calculates a sheet width that does not generate wrinkles in advance in order to prevent wrinkling of the steel strip, and performs rolling below the sheet width.

  However, this makes it difficult to roll a wide material, and restricts the product size that can be manufactured.

  The present invention has been made in view of the circumstances as described above, and when finishing a hot-rolled steel strip into an ultra-thin steel strip by cold rolling, it is possible to accurately prevent wrinkling of the ultra-thin steel strip. It aims at providing the cold rolling equipment and manufacturing method of a steel strip which can be performed.

  In order to solve the above problems, the present invention has the following features.

  [1] A cold rolling mill that performs cold rolling of a steel strip, a tension reel that winds up the cold-rolled steel strip, and installed between the cold rolling mill and the tension reel, A wrinkle suppressing roll for preventing wrinkle generation, wherein the wrinkle suppressing roll is in contact with a steel strip, and a roll deflection changing mechanism for changing a roll deflection shape in the width direction of the wrinkle suppressing roll body. A steel strip cold rolling facility characterized by comprising:

  [2] A method for producing a steel strip using the steel strip cold rolling facility according to [1], wherein a thickness distribution in the width direction during hot rolling of the steel strip is measured, and the thickness of the steel strip is measured. Based on the measurement result of the distribution, the distribution in the sheet width direction of the winding tension at the time of cold rolling is calculated, and based on the calculation result, the roll deflection is performed so that the tension distribution in the sheet width direction at the time of winding is uniform. A method of manufacturing a steel strip, comprising changing a roll deflection shape in a width direction of the wrinkle suppression roll body by a shape changing mechanism.

  ADVANTAGE OF THE INVENTION According to this invention, when finishing a hot-rolled steel strip to an ultra-thin steel strip by cold rolling, generation | occurrence | production of a wrinkle of an ultra-thin steel strip can be prevented exactly. As a result, productivity and yield can be greatly improved in the manufacturing process of the ultrathin steel strip.

It is the figure which showed the equipment structure of the general Sendzimir rolling mill. It is the figure which showed the width direction tension distribution at the time of coil winding. It is the figure which showed the installation structure of one Embodiment of this invention. It is a figure (side view) which shows the structure of the wrinkle suppression roll in one Embodiment of this invention. It is a figure (front view) which shows the structure of the wrinkle suppression roll in one Embodiment of this invention. It is the figure which showed the change of the maximum tension at the time of winding by coil weight and plate crown ratio.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 3 is a schematic diagram of cold rolling equipment according to an embodiment of the present invention. In FIG. 3, a steel strip 4 unwound from a coil 3 mounted on a tension reel 2a provided on one side of a cold rolling mill 1 is rolled through a deflector roll 5a and subsequently provided on the opposite side. The work wound around the tension reel 2b is performed through the deflector roll 5b, and one rolling pass is completed.

  At this time, the wrinkle suppression roll 6a and the pass line roll 7a are disposed in a position close to the tension reel 2a between the tension reel 2a and the deflector roll 5a, and similarly, the tension reel between the tension reel 2b and the deflector roll 5b. The wrinkle suppression roll 6b and the pass line roll 7b are disposed at a position close to 2b. The wrinkle suppressing roll 6a applies bending deformation to the steel strip 4 between the tension reel 2a and the pass line roll 7a by pushing the steel strip 4 from the sheet passing line, and the wrinkle suppressing roll 6b removes the steel strip 4 from the sheet passing line. By pushing, bending deformation is given to the steel strip 4 between the tension reel 2b and the pass line roll 7b. Thereby, the restraining effect by the frictional force between the wrinkle suppressing rolls 6a and 6b and the steel strip 4 is also added, the buckling resistance of the steel strip 4 is improved, and the generation of wrinkles is suppressed.

  In addition, the greatest feature of this embodiment is the structure of the wrinkle suppressing rolls 6a and 6b.

  4 and 5 are a side view and a front view of the wrinkle suppression roll 6b, respectively (note that the wrinkle suppression roll 6b is shown here, but the same applies to the wrinkle suppression roll 6a). The wrinkle suppression roll 6b comes into contact with the steel strip 4 so that the wrinkle suppression roll main body 8 that pushes the steel strip 4 through the plate line and the side opposite to the portion of the wrinkle suppression roll main body 8 that contacts the steel strip 4 are contacted. Then, a plurality (seven in this case) of extrusion rolls 9a to 9g arranged in the width direction and connected to each of the extrusion rolls 9a to 9g, the extrusion force of the extrusion rolls 9a to 9g is And a plurality of (here, seven) fluid pressure cylinders 10a to 10g for independent control in the direction (roll axis direction).

  Thereby, the wrinkle suppression roll 6b can arbitrarily change the roll deflection shape in the width direction of the wrinkle suppression roll body 8 that contacts the steel strip 4 by changing the extrusion force of the extrusion rolls 9a to 9g in the width direction. Is possible. As described above, the same applies to the wrinkle suppression roll 6a.

  When the roll deflection shape of the wrinkle suppression roll body 8 of the wrinkle suppression roll 6a changes, the distance between the tension reel 2a and the wrinkle suppression roll 6a (wrinkle suppression roll body 8) changes in the plate width direction. As a result, the steel strip 4 The distribution in the width direction of the tension acting on the surface changes. Similarly, when the roll deflection shape of the wrinkle suppression roll main body 8 of the wrinkle suppression roll 6b changes, the distance between the tension reel 2b and the wrinkle suppression roll 6b (wrinkle suppression roll main body 8) changes in the plate width direction. The widthwise distribution of tension acting on the steel strip 4 changes.

  For example, when the extrusion rolls 9a and 9g arranged at the end of the wrinkle suppression roll main body 8 are pushed out stronger than the other extrusion rolls, the wrinkle suppression roll main body 8 changes to a concave roll deflection shape. At this time, the distance between the position where the steel strip 4 is in contact with the tension reels 2a and 2b and the wrinkle suppression roll main body 8 becomes longer at the width end portion, and a large tension acts on the steel strip 4 at the plate width end portion. Will do.

  Therefore, when the coil diameter at the central portion of the plate width is increased by the plate crown and a large tension acts on the central portion of the plate width, the extrusion force of the extrusion rolls 9a to 9g is controlled as described above, and the wrinkle suppressing roll By controlling the roll deflection shape of the main body 8, it is possible to prevent a large tension from acting on the center of the plate width.

  In addition, when the roll bending shape of the wrinkle suppression roll main body 8 is convex, it is possible to prevent a large tension from acting on the plate width end portion.

  Moreover, in this embodiment, the extrusion force of the extrusion rolls 9a to 9g is independently controlled, and it is also a great feature that the roll deflection shape of the wrinkle suppression roll body 8 can be arbitrarily changed without replacing the roll.

  As described above, the sheet crown of the hot-rolled steel strip that causes wrinkles varies depending on the hot-rolling conditions. In this embodiment, the roll deflection shape of the wrinkle suppression roll body 8 is changed in accordance with the variation. Therefore, wrinkle generation can be stably prevented.

  Specifically, the sheet crown ratio of the hot-rolled steel strip is measured in advance, and the roll deflection shape of the wrinkle suppression roll body 8 at the time of coil unwinding and winding in cold rolling is extruded based on the measurement results. It controls by the extrusion force of the rolls 9a-9g. That is, it is as follows.

  First, the plate culan ratio of the hot-rolled steel strip is measured with a plate thickness meter using γ-rays or X-rays installed on the exit side of the hot-rolling finish rolling mill. Usually, since a plurality of points in the longitudinal direction of the steel strip are measured, the average value is used as a representative value.

  Next, when the hot-rolled steel strip having the measured sheet crown ratio is cold-rolled, the maximum value in the plate width direction of the unwinding tension acting on the steel strip 4 with respect to the coil weight and the plate of the winding tension The maximum value in the width direction is calculated by elastic analysis. FIG. 6 shows an example of the calculation result of the maximum value of the winding tension with respect to the change in the plate crown ratio and the coil weight. It can be seen that as the plate crown ratio is larger, a larger winding tension acts with a smaller coil weight and wrinkles are more likely to occur.

  Next, in order to make uniform the tension distribution in the plate width direction during rewinding and the tension distribution in the plate width direction during winding, the roll deflection shape proportional to the outer diameter difference in the coil width direction caused by the plate crown is suppressed. The extrusion force of the extrusion rolls 9a to 9g applied to the roll body 8 is calculated by elastic analysis, and the extrusion force of the extrusion rolls 9a to 9g is controlled during rolling.

  The above-mentioned “make the tension distribution in the plate width direction uniform” means that “the compressive stress obtained by multiplying the maximum value of the tension distribution in the plate width direction by the Boisson ratio is less than the buckling limit stress of the steel strip 4. It means "to become." Incidentally, the buckling limit stress of the steel strip 4 can be calculated by a calculation formula of the buckling limit stress of the flat plate in elastic mechanics.

  Thereby, generation | occurrence | production of a wrinkle can be suppressed and it becomes possible to manufacture an ultra-thin steel strip stably.

  Therefore, the methods disclosed in Patent Documents 1 to 3 cannot accurately cope with fluctuations in the sheet crown of the hot-rolled steel strip, but this embodiment can overcome the problem.

  In this embodiment, a hydraulic mechanism is used as the roll deflection shape changing mechanism that changes the roll deflection shape of the wrinkle suppressing roll body 8, but other mechanisms may be used. For example, a mechanism using an electric motor or the like may be used.

  In order to confirm the effectiveness of the present invention, cold rolling of stainless steel containing 18% by mass of Cr and 3% by mass of Al was performed using the cold rolling facility shown in FIG.

A hot-rolled steel strip as a rolling material is a coil having a plate thickness of 1.8 mm, a plate width of 1000 mm, and a weight of 13 tons. The cold rolling mill was a 20-stage Sendzimir rolling mill with a work roll diameter of 70 mm, and cold rolling was performed to a final finished sheet thickness of 100 μm and 50 μm by multi-pass rolling. Rolling at the entry side tension (average unwinding tension) is ^{30kgf / mm 2 (294N / mm} 2), ( the average value of the winding tension) exit side tension was ^{40kgf / mm 2 (392N / mm} 2) .

  First, in place of the wrinkle suppressing rolls 6a and 6b shown in FIGS. 4 and 5 as a conventional example, a concave roll disclosed in Patent Document 1 was installed. The maximum roll diameter (outer diameter of the barrel end) of the concave roll was φ200 mm, the barrel length was 1300 mm, and the ratio of the outer diameter difference between the center of the roll barrel and the barrel end to the maximum roll diameter was 0.03. And the several hot-rolled steel strip (coil) from which a plate crown ratio differs was rolled, and the coil weight until wrinkles generate | occur | produced about each was investigated.

  Next, as an example of the present invention, the wrinkle suppressing rolls 6a and 6b shown in FIGS. 4 and 5 were installed in place of the concave roll. The wrinkle suppression roll body 8 of the wrinkle suppression rolls 6a and 6b has a roll diameter of φ200 mm and a barrel length of 1300 mm. And according to the sheet | seat crown ratio of a rolling raw material (hot-rolled steel strip), the roll bending shape of the wrinkle suppression roll main body 8 is controlled by the extrusion rolls 9a to 9g, and the tension distribution and the winding in the sheet width direction at the time of unwinding are controlled. A plurality of hot-rolled steel strips (coils) having different plate crown ratios were rolled while the tension distribution in the plate width direction at the time of taking was made uniform, and the coil weights until wrinkles were generated for each were investigated.

  Table 1 shows the investigation results of the sheet crown ratio of the rolled material (hot rolled steel strip) and the weight of the coil wound up until wrinkles are generated.

  It can be seen that in the conventional example, as the plate crown ratio of the hot-rolled steel strip increases, wrinkles are generated with a small coil weight. Further, the thinner the finished plate thickness, the smaller the weight of the coil where wrinkles occur, and the lower the productivity, the lower the yield of the thinner material.

  On the other hand, in the example of the present invention, wrinkles did not occur in all the coils even when rolled to the coil weight of the rolled material (hot rolled steel strip).

  This shows that the present invention is extremely effective.

  As described above, in the present invention, the occurrence of wrinkles, which is a problem in cold rolling of ultrathin steel strips, can be suppressed, and the productivity and product yield of cold rolling of ultrathin steel strips can be reduced. It becomes possible to greatly improve.

DESCRIPTION OF SYMBOLS 1 Cold rolling mill 2a, 2b Tension reel 3 Coil 4 Steel strip 5a, 5b Deflector roll 6a, 6b Wrinkle suppression roll 7a, 7b Pass line roll 8 Wrinkle suppression roll main body 9a-9g Extrusion roll 10a-10g Fluid pressure cylinder

Claims (2)

  Cold rolling mill that performs cold rolling of the steel strip, a tension reel that winds the cold rolled steel strip, and a wrinkle of the steel strip that is installed between the cold rolling mill and the tension reel. A wrinkle suppression roll body that contacts the steel strip, and a roll deflection shape change mechanism that changes the roll deflection shape in the width direction of the wrinkle suppression roll body. Steel strip cold rolling equipment.   It is a manufacturing method of the steel strip using the cold rolling equipment of the steel strip according to claim 1, and measures the thickness distribution in the width direction at the time of hot rolling of the steel strip, and the measurement result of the thickness distribution Based on the above, a roll width distribution of the winding tension at the time of cold rolling is calculated, and based on the calculation result, the tension distribution in the width direction of the sheet at the time of winding is uniformed by the roll deflection shape changing mechanism. A method of manufacturing a steel strip, wherein the roll deflection shape in the width direction of the wrinkle suppression roll body is changed.

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