JP6850418B2 - How to manufacture metal strips - Google Patents

Description

The present invention is an invention relating to a method for producing metal strips.

Generally, a steel strip that has undergone a cold rolling process is formed into a metal strip having a desired width by slitting the steel strip in the width direction according to a desired application, and the metal strip is wound into a coil shape and then wound up. Shipped to the process. This metal strip is passed through in contact with several rolls during its manufacturing process. Since swells and meandering are likely to occur due to a slight difference in rotation speed between the rolls, various studies have been made conventionally to avoid meandering.

For example, Patent Document 1 describes a brake mechanism attached to an anchorer to regulate the rotational operation of a coil member, and a horizontal transfer direction of the metal strip and the slit strip by increasing the tension acting on the metal strip and the slit strip. A control unit that controls the brake mechanism so as to approach the direction, a pair of intake rollers that are installed on the metal strip intake side for capturing the metal strip in the slitter and press the metal strip from the vertical direction, and the above. A slitter device is disclosed that includes a pair of feeding rollers that are installed on the slit strip feeding side that feeds the slit strips from the slitter and presses the slit strips from above and below. According to this Patent Document 1, since it is not necessary to use a tension pad that causes a flaw on the surface of the metal strip and it is not necessary to form a loop that causes slack or meandering, a metal strip is specified. It is described that it is possible to cut the slit strip accurately to the width and wind the slit strip without slack, and to avoid deterioration of the quality of the slit strip.

Japanese Unexamined Patent Publication No. 2011-240461

During the cold rolling process described above, the steel strip has a poor shape such as ear waves and medium elongation, and the crown shape is thicker in the center of the width direction than the thickness of both ends in the width direction of the steel strip. The cross-sectional shape and length of the metal strip after the slit processing described above tend to be non-uniform. As a result, steel strips and metal strips meander on the transport roll, and the metal strips tend to bend sideways at the time of slitting, and burrs and surface defects that occur when adjacent metal strips interfere with each other tend to become problems. is there. Tension control by a brake mechanism as in Patent Document 1 is an effective technique for steel strips with very few shape defects, but as described above, if shape defects remain or crowns occur, meandering occurs. It is considered difficult to suppress. On the other hand, there is also a method of installing a separator (partition) between the cut metal strips to suppress meandering and interference of the metal strips, but if the straightness of the metal strips is low, the separator and the metal strips come into contact with each other. , There is a concern that defects such as broken metal strips may occur.
Therefore, the present invention relates to a method for producing metal strips, which can suppress meandering of metal strips after cutting, suppress interference between adjacent metal strips, and reduce the occurrence of lateral bending and burrs.

The present inventor has repeatedly studied a method for controlling the tension of a steel strip before a slit and a method for controlling the tension of a metal strip after the slit. As a result, they have found that the meandering of metal strips can be suppressed by installing bridle rolls on the upstream side and the downstream side of the slitter and further adjusting the bridle roll conditions on the downstream side of the slitter appropriately, and came up with the present invention.

That is, the present invention
Unwinding process to unwind the steel strip after finish cold rolling,
A first tension control step of passing the unwound steel strip through a first bridle roll having a plurality of constituent rolls, and
A slit process for cutting a steel strip passed through the first bridle roll into a plurality of metal strips, and
A second tension control step of passing the cut metal strip through a second bridle roll having a plurality of constituent rolls, and
It is provided with a winding process for winding a metal strip passed through the second bridle roll.
The constituent roll of the second bridle roll is a metal roll having a surface roughness of Ra ≦ 1.0 μm.
The peripheral speed of the constituent roll located on the most downstream side of the second bridle roll is 1.01 to 1.12 times faster than the transport speed of the steel strip between the unwinding process and the first bridle roll. It is a method for manufacturing metal strips, which is characterized by being set.
Preferably, at least one of the constituent rolls of the first bridle roll is a rubber roll.

According to the present invention, it is possible to provide a method for producing a metal strip capable of suppressing meandering of the metal strip at the time of slitting and reducing the occurrence of lateral bending and burrs.

It is a figure which shows an example of the apparatus used in the manufacturing method of this invention. It is a figure which shows another example of the apparatus used in the manufacturing method of this invention. It is a figure which shows an example of the apparatus used in the conventional manufacturing method.

The present invention will be described in detail below. The composition of the metal strips that are the subject of the present invention is preferably applied to those having a composition of high carbon stainless steel generally used for blades, valves, etc., and those having a composition of martensitic stainless steel. It is more preferable to apply. This is because martensitic stainless steel has a relatively high hardness, it is difficult to completely remove defects such as ear waves and medium elongation in the rolling process, and the crown tends to remain, so meandering and swelling tend to occur during slitting. .. As a more preferable composition, 0.3 to 1.5% C, 10 to 18% Cr, 1% or less Si, and 1.5% or less Mn are essentially contained, and if necessary, 3% or less. It is an Fe-based alloy containing Mo.

FIG. 1 shows an example of the device configuration from unwinding to winding used in the present embodiment. The steel strip 10 that has completed the cold rolling process is unwound from the unwinding device 1, and the tension and the conveying speed are adjusted by the first bridle roll 4 composed of the constituent rolls 4a to 4d. The steel strip 1 adjusted to a predetermined tension and speed is slit into a plurality of strips by a slitter 3 composed of a cylindrical upper blade cutter 3a and a cylindrical lower blade cutter 3b to form a metal strip 11. The tension of the metal strip 11 is adjusted again by the second bridle roll having the constituent rolls 5a and 5b, and then the metal strip 11 is wound by the winding device 2 to become a metal strip coil. Hereinafter, the apparatus configuration of FIG. 1 will be described unless otherwise specified. However, when cutting a wide steel strip into multiple strips, for example, as shown in FIG. 2, the metal strips are alternately branched to form a second bridle roll. May be provided at two locations and wound by different winders.

(Unwinding process, first tension control process)
First, the steel strip 10 that has finished cold rolling is unwound by the unwinding machine 1 (unwinding step), and then the tension and transport speed of the steel strip are adjusted from 4 to the first bridle roll. In the present embodiment, the tension is controlled by the first bridle roll 4 before the slitter 3. As a result, by using the bridle roll, the unwound steel strip is tension-controlled while being wound around each of the constituent rolls 4a to 4d. Even if it is formed in a strip, it is possible to suppress the deviation in the width direction by supporting the steel strip with multiple rolls, and it is possible to perform stable slitting by improving the straightness of the steel strip. is there. Even if this tension control is performed by the tension pad or the brake mechanism built in the unwinder, the steel strip being conveyed tends to meander easily due to the crown or ear wave. In the present embodiment, even if the thickness of the widthwise end portion of the steel strip is about 3% thinner than the thickness of the widthwise central portion of the steel strip, the meandering prevention effect can be exhibited. .. The winding angle of the steel strip around the first bridle roll (indicating the contact angle between the steel strip and the roll as shown in FIG. 1C. In FIG. 1, the not shown other than the constituent roll 4a is omitted) is being conveyed. It can be set to 100 ° to 270 ° in order to firmly support the steel strip and ensure that the meandering prevention effect is exhibited. More preferably, it can be set to 150 ° to 250 °.

The number of constituent rolls of the first bridle roll in the present embodiment can be selected from the range of 2 to 6 depending on the steel strip winding tension at the end of the rolling step which is the previous step. As the number of the constituent rolls is increased, the tension between the unwinding device and the first bridle roll can be set higher. Therefore, for example, when the steel strip winding tension in the previous step is too strong (for example, in the present embodiment). , When the tension (unit tension) per unit cross-sectional area of the steel strip is 7 kgf / mm ² or more), the steel strip may rewind during the unwinding process, and vibration due to tension fluctuation or the like may occur. In order to suppress this vibration, it is effective to set a high tension between the unwinder and the first bridle roll, so it is preferable to set the number of the first bridle rolls to six. The material of the first bridle roll can be selected from existing materials such as metal and rubber, but it is preferable to use a rubber roll at least at one place. Since the rubber roll has a higher coefficient of friction than the metal roll, it is possible to suppress slippage between the steel strip and the roll and prevent the constituent roll from slipping. The materials of the metal roll and the rubber roll described above can be appropriately selected depending on the type of steel sheet. For example, the first bridle roll of the present embodiment is composed of two metal rolls and two rubber rolls, the metal roll is a carbon steel base material obtained by cemented carbide spraying or chrome plating, and the rubber roll is nitrile rubber. You can choose the one made of. The surface roughness of the metal roll can be set to 1.0 μm or less in arithmetic average roughness Ra in order to appropriately suppress friction and smoothly convey the steel strip.

In the present embodiment, the transfer speed between the unwinder and the bridle roll is controlled by controlling the material, the number of the first bridle rolls, and the peripheral speed. This transport speed can be appropriately adjusted depending on the application, but in order to maintain good machining accuracy at the time of slitting, the upper limit can be about 200 m / min. Further, in the slitter process described later, the tension (unit tension) applied to the steel strip between the first bridle roll and the second bridle roll described later is set to ^{1 to 3 kgf / mm 2 in order to perform an appropriate slit.} be able to.

(Slitter process)
Subsequently, the steel strip 10 coming out of the first bridle roll 4 is cut by the slitter 3. The slitter 3 used in the present embodiment cuts a steel strip in cooperation with the cylindrical upper blade cutter 3a and the cylindrical lower blade cutter 3b. In the present invention, the first bridle roll 4 and the second bridle roll 5 described later have high straightness of the steel strip. Therefore, for example, when a wide steel strip of about 700 mm is cut into multiple metal strips having a width of 4 mm. Since meandering is suppressed, it is possible to transport without a separator. The peripheral speed of this slitter is preferably set to 1.01 to 1.12 times the transport speed between the unwinder and the first bridle roll. The upper limit of the rotation speed of the slitter, which is more preferable, is 1.08 times. By keeping the speed within the above speed range, it is possible to suppress burrs at the edge portion generated in the steel strip at the time of slitting and obtain a higher quality metal strip.

(Second tension control process)
The present embodiment has a second tension control step in which the metal strip 11 formed by the slit step is tension-controlled by the second bridle roll 5. After that, the metal strip 11 is wound by the winder 2 to produce a metal strip coil in which the metal strip is wound into a coil shape (winding step). The second bridle roll 5 adjusts the tension of the metal strip 11 to a tension suitable for hoisting. Further, by supporting the metal strip 11 with the second bridle roll 5, the meandering of the cut metal strip is suppressed, and contact between adjacent metal strips is prevented even if a separator is not formed between the metal strips. It is possible to wind it up. Of the constituent rolls 5a and 5b of the second bridle roll 5, the peripheral speed of the constituent roll 5b (hereinafter, also referred to as the most downstream constituent roll) installed on the most downstream side is 1.01 of the transport speed of the steel strip. It is also a feature of the present invention to set the value from times to 1.12 times. As a result, the force with which the metal strip 11 is drawn into the second bridle roll 5 increases, so that the straightness of the metal strip 11 is greatly increased, and even metal strips 11 having different lengths can be wound without causing slack. It is possible. If the peripheral speed of the most downstream constituent roll is less than 1.01 times, problems such as slack occur in the metal strip immediately after the slit. When the peripheral speed of the most downstream constituent roll exceeds 1.12 times, a large slip occurs between the roll and the metal strip, and a flaw tends to occur on the surface of the metal strip. The lower limit of the peripheral speed of the most preferable downstream configuration roll is 1.02 times, more preferably 1.03 times, the transport speed of the steel strip. Further, the upper limit of the peripheral speed of the most preferable downstream configuration roll is 1.08 times. The constituent roll of the second bridle roll is preferably made of metal and has a Ra of 1.0 μm or less. A more preferable Ra is 0.8 μm or less, and a more preferable Ra is 0.6 μm or less. As described above, due to the crown shape and wavy shape of the steel strip, a metal strip made by cutting from the widthwise end side of the steel strip and a metal made by cutting from the widthwise center side of the steel strip. The cross-sectional shape and the length of the strip are different from those of the strip. By using a roll made of metal and Ra of 1.0 μm or less for the second bridle roll, short metal strips slide on the roll to some extent, which is caused by breakage due to excessive pulling or sagging of too long strips. It is possible to suppress the lateral bending. The number of constituent rolls of the second bridle roll in the present embodiment is not particularly limited, and the effect of the present invention can be obtained with at least two rolls.

Prepare a martensitic stainless steel strip having the composition shown in Table 1, having a length of 4000 m and a width of about 400 mm, and being cold-rolled for finishing. A metal strip having a width of 4 mm was produced by unwinding, slitting, and winding under the condition of (conveying speed up to one bridle roll) of 100 m / min. When observing the martensitic stainless steel strip before cutting in advance, ear waves with a maximum lift height of about 2 mm remain, and the plate thickness at the end is about 2% compared to the plate thickness at the center. I confirmed that it was thin. Further, the constituent rolls 4a and 4b of the first bridle roll are arranged with nitrile rubber rolls, the 4c and 4d are arranged with metal rolls obtained by plating a carbon steel base material with chrome, and the second bridle roll is made of carbon steel. After chrome plating was applied to the base material of No. 1, a metal roll having Ra adjusted to about 0.6 μm by mirror polishing was placed. In the sample of Example 1 of the present invention, the peripheral speed of the most downstream constituent roll 5b of the second bridle roll 5 was adjusted to 1.03 times the transport speed (the transport speed from the unwinding device to the first bridle roll). The sample of Comparative Example 11 had the same peripheral speed as the transport speed. As a result of the experiment, the example of the present invention could be wound up without any defect. On the other hand, in the comparative example, when a slit of about 500 m was made, meandering occurred in the metal strip at the end end, and a problem occurred in which the metal strip overlapped with the adjacent metal strip.

1 Unwinder 2 Winder 3 Slitter 3a Cylindrical upper blade cutter 3b Cylindrical lower blade cutter 4 First bridle roll 4a, 4b, 4c, 4d Composition roll of first bridle roll 5 Second bridle roll 5a Second bridle Roll configuration Roll 5b Most downstream configuration Roll 10 Steel strip 11 Metal strip 20a, 20b Loop C Winding angle

Claims (2)

Unwinding process to unwind the steel strip after finish cold rolling,
A first tension control step of passing the unwound steel strip through a first bridle roll having a plurality of constituent rolls, and
A slit process for cutting a steel strip passed through the first bridle roll into a plurality of metal strips, and
A second tension control step of passing the cut metal strip through a second bridle roll having a plurality of constituent rolls, and
It is provided with a winding process for winding a metal strip passed through the second bridle roll.
The constituent roll of the second bridle roll is a metal roll having a surface roughness of Ra ≦ 1.0 μm.
The peripheral speed of the constituent roll located on the most downstream side of the second bridle roll is 1.01 to 1.12 times faster than the plate passing speed of the steel strip between the unwinding process and the first bridle roll. A method for manufacturing metal strips, which is characterized in that it is set to a high degree. The method for producing a metal strip according to claim 1, wherein at least one of the constituent rolls of the first bridle roll is a rubber roll.

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