JP2009034726A5 - - Google Patents

Description

Tension leveler

The present invention relates to a tension leveler that corrects a defective shape of a metal strip .

The tension leveler conventionally used, tensioned strip by the entry side bridle roll and the exit-side bridle roll, the strip being arranged in staggered divided into upper and lower two groups lying between the two bridle rolls cylinder Using a mold roll, the strip is bent repeatedly to correct it. (E.g., Patent Document 1 and Non-Patent Reference 1.).
These tension levelers usually have an extension roll portion and a shape correction roll portion, both of which are straightened by bending and pulling the strip using a roll. Therefore, the strip after correction is flat in appearance due to the balance of the residual stress, but there is a large residual stress inside the strip . (For example, refer nonpatent literature 2. ).
Although the strip is tensioned between the two bridle rolls and corrected without repeated bending, the tensile force is excessive, and the strip surface is easily scratched by the two bridle rolls. .

Japanese Patent No. 3440083 Edited by Japan Society for Technology of Plasticity, Orthodontic Processing, Corona, published January 20, 1992, p. 90-129 Proceedings of the Japan Iron and Steel Institute, Materials and Processes, published March 1, 2003, Vol. 16 (2003) No. 2P. 384-387

The band plate corrected with the conventional tension leveler described above has large residual stress inside, and deforms again as the residual stress is released by subsequent processing, i.e. cutting, surface dissolution removal, heat treatment, etc. When printing on the surface of the strip, inconvenience occurred.

The present invention is intended to solve the problem of the residual stress of the strip corrected by the conventional tension leveler, and not only achieves the flatness of the strip, but also reduces the residual stress and uses less deformation in the subsequent processing. The purpose is to obtain a tension leveler that can be corrected to an easily stripable strip . Furthermore, it is desirable that the tensile force necessary for correction can be reduced as much as possible.

In order to achieve the above object, the tension leveler of the present invention comprises an entry side bridle roll, an exit side bridle roll, and a pressure unit installed between the two bridles. Pressurizing unit is shorter interval over the entire width of the front and back surfaces of the strip, applying a high pressure, is a device intended to reduce the longitudinal tensile strength of the strip. The peripheral speed of the exit side bridle roll is slightly larger than the peripheral speed of the input side bridle roll, and there is a difference in peripheral speed between the two bridle rolls. Therefore, the strip wound between the inlet and outlet bridle rolls is pulled, and when passing through the pressurizing unit, it is plastically stretched and corrected at a constant stretch ratio determined by the difference in peripheral speed between the bridle rolls. The

The purpose of the pressurizing unit of the present invention is to perform tension correction without bending the band plate between the entry side exit side bridle rolls. When pressure unit has not been installed, the stretching of the strip takes place concentrated at the least tensile strength due to variations in the intensity of the strip to the exit side bridle roll inlet from the outlet of the entry side bridle roll, the strip Cannot be evenly corrected over its entire length. When the pressure unit is installed, the strip is immediately plastically stretched upon entering the center of the pressure unit, it is that moment corrected, is substantially uniformly corrected over its entire length with the progress of the strip. No bending is applied to the strip during the correction process, and the residual stress of the strip after correction is small.

Two upper and lower cylindrical hollow metal roll is present built Marete so as to sandwich the strip to pressurizing unit. Its perpendicular circular cross section to the axis of the hollow roll by the pressure of mutual hollow roll slightly flattened deformed hollow roll surface further contact pressure between the strip contact strip and familiar faces deformed. The strip is pressed against the hollow roll with a narrow rectangular contact surface, and in combination with the tension of the two bridle rolls, it is plastically stretched at the center line position of the hollow roll to achieve the correction purpose. Plastic stretching strain of the tensile testing of the strip (horizontal axis) over stress (ordinate) slope of the curve becomes smaller, it extends to Kazuku near as possible zero. In steel, since the yield point elongation satisfies this condition, the steel is often stretched at the yield point. The reason why the hollow roll is used as the roll in contact with the band plate of the pressure unit is the flexibility of the shape of the hollow roll. Since the solid roll has high rigidity and is difficult to be deformed, even a very small dimensional error between the strip and the roll itself causes a large difference in the contact pressure between the strip and the roll, and therefore cannot be used for the roll in contact with the strip . If necessary to suppress the bending of the hollow roll, a backup roll is used.

The characteristics of the pressure unit required for straightening the strip can be calculated and estimated using plastic theory. That is, the contact stress can be calculated using the Hertz contact theory from the elastic modulus of the hollow roll cylinder and the strip , the diameter of the hollow roll and the size of the rolling force. In the hollow roll, the circular cross-section is deformed slightly flat, and the contact chord width and deformation arc height due to contact can be calculated by local deformation due to Hertz stress. And strength of the rolling force of the hollow roll, tension from the friction coefficient between the hollow roll and the band plate frictional resistance can be calculated. Here, the tensile friction resistance means that when the strip is pulled between the two bridle rolls and is plastically stretched at the centerline position of the hollow roll, the strip is stretched by the friction between the entrance and exit sides of the hollow roll and the strip. It is a force to resist. The lower the value, the easier the strip stretches plastically, so the surface of the hollow roll is forcedly lubricated to reduce the tensile frictional resistance. Further, the change in the width of the strip due to the stretching of the strip and the contact pressure between the hollow rolls is restrained, and a width restraining force is induced in the strip . The tension on the strip required for correction between both bridle rolls can be calculated and estimated using the plastic shear stress, yield conditions Mizesu from 3 spindle stress correction position of the strip of the strip. At the same time, the tension thickness and width of the strip, the elastic modulus of the hollow roll and the strip, work hardening degree and yield point of the strip, the hollow roll rolling force and as a function of the coefficient of friction between the diameter and the hollow roll and the strip Yes, the value can be theoretically calculated from the specifications of the pressure unit and the characteristics of the strip .

When yield strength of the strip to correct is significantly lower than the tensile strength may elongation begins strip of the strip in the entry side bridle roll is being damaged slipped bridle roll surface. In this case, an entry-side bridle roll and a pair of pressure units are added, and a bridle roll, a pressure unit, a bridle roll, a pressure unit, and a bridle roll are connected in series, and the second bridle roll is a shared bridle roll for the entry and exit sides. If so, this problem can be solved since the tension of the strips passing through the two pressure units can be increased in a stepwise manner.

Residual stresses of the strip which was corrected with a tension Te Bellah of the present invention is a valence equivalent to the residual stress of the strip which was corrected with stretcher leveler residual stress is evaluated with the lowest among various straightener, conventional Compared with the tension leveler, it can be expected that the residual stress is extremely small. That is, the strip does not have a bending stress at the correction point, and the pressurizing strength of the pressurizing unit is less than that of a skin pass mill or the like, and there is relatively little friction involved in the strip correcting process. Residual stress characteristics of the material of the strip of the strip which was corrected with a tension leveler of the present invention, although varies greatly according to the specifications and the operation method of the tension leveler, in strip surface compressive stress of 15～40MPa, at the center of the strip It is calculated as a tensile stress of 10 to 20 MPa. Since the straightening process of the present invention is continuously performed while the strip is long, it is highly efficient.

Embodiments of the present invention are shown in FIGS.
Figure 1 is a tension leveler of the present invention, by compressing the front and back of the strip S at a pressure unit 1 between the inlet side bridle roll 5 and the exit-side bridle roll 6, exit the upper fill side strip S Correction is performed by pulling between the bridle rolls 5 and 6 on both sides. The arrow indicates the traveling direction of the strip S. The both bridle roll 5,6 magnitude more large bridle rolls 52 for giving a strong tensile force to the strip S, made small bridle roll 53, bending since the front and rear pressure unit 1 strong tensile force strip Increase the diameter to avoid yielding due to The presser roll 51 is installed to apply an initial tension to the strip S at the entry side bridle roll 5 and the exit side bridle roll 6. When the strip S passes through the pressurizing unit 1, the strip S is not bent and is plastically stretched at a constant stretch rate determined by the peripheral speed difference between the entry-side and exit-side bradle rolls 5 and 6. Is called.

The drive systems of the entry side exit side bradle rolls 5, 6 are mechanically or electrically connected (although not shown in the drawing), and the tension of the strip S between the bradle rolls 5, 6 is connected. The power is circulated through the. Since the entry-side bridle roll 5 brakes the progress of the strip S, the power is returned to the drive system. Since the exit-side bridle roll 6 drive the strip S consumes power supplies most of its consumption to cover the power that is returned from the entry side bridle roll 5, the drive system is less power from the outside You can drive.

2, FIG. 3 shows the pressure unit 1. Two cylindrical hollow rolls 3 are incorporated in the pressure unit 1, and the hollow roll 3 is supported by a backup roll 4. The upper backup roll chock 12 of the backup roll 4 is pushed by the reduction device 21. Figure 4 shows a hollow roll 3, its hollow roll body 31 is supported lifting hollow Roruhabu 32 to easily deform. During operation of the pressurizing unit, the hollow roll body 31 is hollow, so that it is slightly flattened and comes into surface contact with the strip S. Strip S is drawn corrected object at a constant elongation rate by the peripheral speed difference between the inlet and outlet both bridle rolls at the center of the pressure unit 1 in less stretching force reduces the tensile strength in the longitudinal direction under pressure is achieved The Figure 5 shows the backup roll 4, a middle roll 4 1 real prevents bending and bus acknowledgment up a hollow roll 3 has high rigidity as a whole. The hollow roll 3 and the backup roll 4 have a hollow roll bearing 33 and a backup roll bearing 42 , respectively, and are rotatable.

Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. For example the inlet side outlet side and that the two bridle roll alternates like the other traction devices pinch rolls, etc. to fill the plastic in place of the hollow roll hub between the hollow roll body and the hollow roll shaft, various changes, It will be apparent to those skilled in the art that improvements, combinations, and the like are possible.

Shape failure has become a problem due to the residual Tome応 force of a thin plate or the like of the food can be a shadow mask and printing of television and Deployment. The strip processed by the tension leveler of the present invention has little residual stress and good flatness of the strip , so that it is expected to improve the manufacturing process of these products and improve the yield.

Elevation of tension leveler using pressure unit Elevation view of pressure unit AA arrow sectional view of FIG. Cross section of hollow roll Elevated view of backup roll

1. Pressurizing unit 3, hollow roll 4, backup roll 5, entry side bridle roll 6, exit side bridle roll 11, stand 12, upper backup roll chock 13, lower backup roll chock 14, hollow roll chock 16, backup roll chock holding plate 17, Hollow roll chock holding plate 18, backup roll balance cylinder 19, hollow roll balance cylinder 20, upper connection beam 21, roll reduction device 22, lower connection beam 31, hollow roll barrel 32, hollow roll hub 33, hollow roll bearing 34, hollow roll shaft 41, roll 42, backup roll bearing 51, holding roll 52, large-diameter bridle roll 53, small-diameter bridle roll S, strip