JP3221075B2 - Method of measuring tension distribution in width direction of metal strip during rolling and apparatus used for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a metal strip, particularly a strip, by cold rolling, and a method for measuring the distribution of the tension generated in the strip during rolling in the strip width direction. Related to the device.

[0002]

2. Description of the Related Art In order to roll a metal strip (hereinafter referred to as "strip") into a desired shape, the distribution of the tension applied to the strip during rolling in the strip width direction is grasped. It is necessary to control the rolling mill based on the data. As a technique for measuring the tension distribution of a strip during rolling, a method in which a tension detection roll embedded with a load cell is brought into contact with the strip is currently the mainstream, and in addition, displacement of the strip by an electromagnet is applied. There is a method of obtaining the tension from the displacement amount.

When a tension detecting roll is used, there is a danger that the surface of the steel strip may be damaged by contact. On the other hand, the displacement due to the electromagnetic force cannot be used when rolling a non-magnetic material.
Therefore, there has been a demand for a measurement technique free of such disadvantages and limitations.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to measure a tension in a strip width direction at the time of strip rolling, which can be carried out in a non-contact manner irrespective of the type of material in response to the above-mentioned demand. It is to provide a method and an apparatus.

[0005]

According to the present invention, a method for measuring a tension distribution in a sheet width direction during rolling of a metal strip according to the present invention is shown in FIG.
As shown in FIG. 2, fluid was sprayed simultaneously or sequentially at a plurality of positions in the width direction of the metal strip running during cold rolling, thereby moving the metal strip. The method comprises detecting a minute displacement and calculating a tension value at each blowing position from the displacement amount using the following equation I. − (12 EI / L ³ ) υ _n−1 − (6 EI / L ² ) θ _n−1 +2 (12 EI / L ³ + T _n ) υ _n − (12 EI / L ³ ) υ _{n + 1} + (6 EI / L ² ) θ _{n + 1} = f (I) where E: elastic modulus of the strip metal I: second moment of area L: distance between measurement points _Tn : tension f: external force n, n-1, n + 1: selected in the width direction A center point of the plurality of fluid spraying positions and points 両 側_n , _{ｎ n-1} , υ _{n + 1} on both sides thereof: displacement amounts θ _n−1 , θ _{n + 1 at} points n, _n−1 , _{n + 1} : point n−1 , N + 1 The derivation of the above equation will be described later.

The fluid to be blown may be either a liquid or a gas, and the type thereof can be arbitrarily selected as long as it is harmless to the metal of the strip. The simplest and most advantageous is compressed air.

[0007] The measurement must be performed at each measurement point arranged in the width direction of the strip, and the time required for one measurement is within one second, while the rolled strip travels a certain distance. Therefore, the position of the measurement point in the longitudinal direction may be shifted at predetermined intervals in the running direction of the strip in accordance with the order of spraying. Thereby, it is possible to calculate the tension at each position substantially on one line in the plate width direction.

In order to carry out the above-described method for measuring the tension in the width direction of the strip, the apparatus for measuring the distribution of tension in the width direction of the metal strip during rolling of the metal strip according to the present invention comprises means for feeding a metal strip from a coil ( 1) a roll (2) for rolling the unwound strip, and a rolling strip (9) in addition to a rolling device consisting essentially of means (3) for winding the rolled strip.
Fluid spraying means (4) arranged at a plurality of positions in the plate width direction, a displacement sensor (5) for detecting minute displacement generated on the strip by spraying, and a displacement sensor based on the detected displacement amount. An arithmetic unit (6) for calculating the tension according to the formula I is provided. − (12 EI / L ³ ) υ _n−1 − (6 EI / L ² ) θ _n−1 +2 (12 EI / L ³ + T _n ) υ _n − (12 EI / L ³ ) υ _{n + 1} + (6 EI / L ² ) θ _{n + 1} = f (I) where E: elastic modulus of the strip metal I: second moment of area L: distance between measurement points _Tn : tension f: external force n, n-1, n + 1: selected in the width direction A center point of the plurality of fluid spraying positions and points 両 側_n , _{ｎ n-1} , υ _{n + 1} on both sides thereof: displacement amounts θ _n−1 , θ _{n + 1 at} points n, _n−1 , _{n + 1} : point n−1 , N + 1

The fluid blowing means is suitably a nozzle that blows out rolling air for a predetermined time, for example, 500 milliseconds.

As the displacement sensor, there are an eddy current displacement meter, an ultrasonic displacement meter, a laser distance meter and the like, and any of them can be used. For magnetic materials, an electromagnetic displacement meter can also be used. Is optimal. In FIG. 1, reference numeral (7) denotes a control device for tilting the roll in the width direction or changing the deflection of the backup roll to control rolling down to the strip based on the result of the above calculation. It is.
In addition, the cooling oil can be supplied in the width direction of the strip based on the calculation result.

[0011]

With reference to FIG. 3, the intrinsic tension F is obtained from the displacement d when an external force f is applied to the metal strip 9 as follows. That is, when ignoring the influence from the portion adjacent in the width direction, the theoretical formula is as follows: If F = f / sin (tan ~ ¹ d / l) d << 1, F ≒ f · l / d Good. Therefore, it can be seen that the tension and the displacement are in inverse proportion.

Actually, a 375 mm wide × 0.25 mm thick 4
The relationship between the stress and the displacement was measured with an external force f = 200 gf on the band of the 2Ni—Fe alloy, and the result of FIG. 4 was obtained.
The data in FIG. 4 shows that the displacement is greater at both edges of the band for the same stress than at the center. This is because one of the two edges is a free end.

Therefore, when the distribution of the tension and the displacement of the model shown in FIG. 5 are obtained by the finite element method in consideration of the influence of the material adjacent in the width direction, the above-described formula I is obtained.

[0014]

According to the above-described formula I, stress was calculated at nine points in the width direction of the above-mentioned strip, also based on the displacement amount when displaced by an external force of 200 gf.

The result is shown in FIG. 6 in comparison with the output of the strain gauge. There was relatively good agreement.

[0017]

According to the present invention, the tension distribution in the strip width direction of the steel strip can be measured in a non-contact manner and with high accuracy without fear of damaging the surface of the steel strip. By controlling the rolling rolls, it becomes easy to manufacture a steel strip having a desired cross-sectional shape (for example, the thickness of the central portion is thicker than both edges). Since the driving force for applying the displacement is not an electromagnet, it can be applied regardless of the magnetic non-magnetism of the material.

The materials to which the present invention is applied include a wide range of materials such as various types of copper and stainless steel, in addition to the 42Ni-Fe alloy shown as an example.

[Brief description of the drawings]

FIG. 1 is a side view illustrating the principle of the method of the present invention and showing the basic configuration of the apparatus of the present invention.

FIG. 2 is an enlarged view of a cross section taken along a line II in FIG. 1;

FIG. 3 is a conceptual diagram for deriving a relationship between a displacement when an external force is applied to a band plate and an internal stress when the influence in the width direction is ignored.

FIG. 4 is a graph showing a relationship between an internal stress and a displacement when an external force is applied to a metal strip.

FIG. 5 is a conceptual diagram for deriving a relationship between a displacement when an external force is applied to the band plate and an internal stress when the influence in the width direction is taken into consideration.

FIG. 6 is a graph showing the stress existing in the strip calculated from the measured value of strain and showing the distribution in the strip width direction.

[Explanation of symbols]

 Reference Signs List 1 Means for feeding metal strip 2 Rolling roll 3 Means for winding rolled strip 4 Fluid spraying means 5 Displacement sensor 6 Computing unit 7 Controller 9 Strip

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01L 5/04-5/10

Claims (6)

(57) [Claims] 1. A fluid is sprayed on a metal strip running under cold rolling at a plurality of positions in a width direction of the strip, and a minute displacement generated on the strip is detected to thereby displace the strip. A method of measuring the tension distribution in the width direction of a metal strip at the time of rolling a metal strip, comprising calculating a tension value at each spraying position from the amount by using the following formula I. − (12 EI / L ³ ) υ _n−1 − (6 EI / L ² ) θ _n−1 +2 (12 EI / L ³ + T _n ) υ _n − (12 EI / L ³ ) υ _{n + 1} + (6 EI / L ² ) θ _{n + 1} = f (I) where E: elastic modulus of the strip metal I: second moment of area L: distance between measurement points _Tn : tension f: external force n, n-1, n + 1: selected in the width direction A center point of the plurality of fluid spraying positions and points 両 側_n , _{ｎ n-1} , υ _{n + 1} on both sides thereof: displacement amounts θ _n−1 , θ _{n + 1 at} points n, _n−1 , _{n + 1} : point n−1 , N + 1 2. The method according to claim 1, wherein compressed air is used as the fluid.
the method of. 3. The position in the longitudinal direction of spraying a fluid is shifted at predetermined intervals in the running direction of the strip according to the order of spraying, so that the tension can be calculated at each position substantially on the same line in the width direction of the strip. 2. The method of claim 1, wherein said method is performed. 4. A roll consisting essentially of a means (1) for unwinding a metal strip from a coil, a roll (2) for rolling the unrolled strip and a means (3) for winding the rolled strip. Fluid spraying means (4) arranged at a plurality of positions in the width direction of a running strip (9) for detecting a minute displacement generated in the strip by spraying. A tension distribution measuring device in the width direction of a metal strip at the time of rolling a metal strip, comprising a displacement sensor (5) and a calculator (6) for calculating a tension based on the following equation I based on the detected displacement amount. − (12 EI / L ³ ) υ _n−1 − (6 EI / L ² ) θ _n−1 +2 (12 EI / L ³ + T _n ) υ _n − (12 EI / L ³ ) υ _{n + 1} + (6 EI / L ² ) θ _{n + 1} = f (I) where E: elastic modulus of the strip metal I: second moment of area L: distance between measurement points _Tn : tension f: external force n, n-1, n + 1: selected in the width direction A center point of the plurality of fluid spraying positions and points 両 側_n , _{ｎ n-1} , υ _{n + 1} on both sides thereof: displacement amounts θ _n−1 , θ _{n + 1 at} points n, _n−1 , _{n + 1} : point n−1 , N + 1 5. The apparatus according to claim 4, wherein a nozzle for jetting compressed air for a predetermined time is used as the fluid blowing means. 6. The apparatus according to claim 4, wherein an eddy current displacement meter is used as the displacement sensor.