JP3319710B2 - Control method of bending of metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for reducing an optimum value of a tension or a diameter of a roll applied to a metal strip in order to reduce a plastic deformation such as a bending applied to the metal strip when the metal strip passes through a roll at the time of manufacturing. The present invention relates to a method for controlling the curve formation of a metal strip, which can determine the curl toyo of an optimum metal strip.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional production line for metal strips, for example, a production line for metal strips such as mild steel, copper, copper alloy and stainless steel. As shown, metal strip J
, After a rolling process, a tension leveler process and a slitter process are performed, and finally, inspection and rewinding are performed before shipment.

In the slit line shown in FIG. 6, a metal strip J wound in a roll shape is a pay-off reel (POR).
And a pair of bridle rolls b and c for controlling the tension, a tension roll d, a wrinkle removing roll e, a deflector roll f, distribution rolls g and h, and guide rolls i and j.
No. 1 tension reel (No. 1TR), No. 1 It is wound on a 2 tension reel (No. 2TR). here,
No. via the distribution roll g. 2TR winding method Passing method A, sorting roll g, guide roll i, j
Through No. No. 2 is passed through the winding method B and the sorting roll h. The method of winding in 1TR is referred to as a passing plate method C. The metal strip J is cut in the width direction by a slitter S installed between the wrinkle removing roll e and the deflector roll f, and is trimmed or divided into a plurality of strips.

[0004]

As mentioned above, the metal strip passes through various rolls during production. At that time, it is known that the bending habit given to the metal strip, that is, the plastic deformation of the metal strip, has a great influence on the appearance and size of the curled toyo and the like of the metal strip product.

In the slitter line shown in FIG. 6, how the curl of the metal strip J unwound from the pay-off reel (POR) is changed by each roll and taken up on the tension reel (TR) was measured. . The measurement was performed on three types (0.15 t, 0.20 t, 0.25 t) having different thicknesses using mild steel (KS) metal strips. 0.15mm and 0.25mm thick metal strip J
As shown in the figure, the line was operated by three kinds of passing methods A, B and C. On the other hand, the metal strip J having a thickness of 0.20 mm was operated in a line by the passing method B. When the line speed and tension are stabilized, the line is stopped and P1-
Sampling was performed at the position of P12.

The unit tension applied to each metal strip J has a thickness of 0.15 mm, 0.20 mm and 0.1 mm.
For 25 mm, 3.5 kg / square mm, 2.4 kg / square mm and 2.0 kg / square mm, respectively.
And

[Table 1]

[Table 2]

Tables 1 and 2 list the effect of each roll on the curl and toyo according to the plate thickness. From these tables, it can be seen that the deflector roll a, the sorting roll g, and the guide rolls i and j having an outer diameter of 180 mm or less affect the curl / toyo.

However, in recent years, the size of a curled toyo of a metal strip wound in a reel shape has been restricted to fall within a certain allowable limit (the curled toyo standard). The restrictions are getting stricter year by year. The present inventor, in order to keep the Carl Toyo within the standard, that is, to minimize the change of the Carl Toyo,
By properly selecting the outer diameter of each roll in the slitter line, it has been found that the influence on the curl and toyo can be eliminated, and the present invention has been completed.

Therefore, an object of the present invention is to reduce the plastic deformation such as the curvature applied to a metal strip when the metal strip passes through a roll at the time of production, and to optimize the tension U applied to the metal strip or the roll diameter R. It is an object of the present invention to provide a method for controlling the curve formation of a metal strip, which can determine a value and thereby obtain an optimum curl toyo of the metal strip.

[0010]

SUMMARY OF THE INVENTION The present invention, which solves the above-mentioned problems, has an object to reduce a plastic deformation such as a curvature applied to a metal strip when the metal strip is passed through a roll at the time of manufacturing the metal strip. U or roll diameter R,
(%) So that 0.1 <X <0.16.
The present invention provides a method for controlling the curvature of a metal strip, which is determined from E + t / 2R, thereby obtaining an optimum curl / toyo of the metal strip. Where E is the Young's modulus of the metal strip, t
Is the thickness of the metal strip.

When the metal strip is wound around the surface of the roll, the outer surface of the metal strip is longer than the neutral surface (the surface that does not expand and contract due to bending), and a correspondingly large distortion is generated. If the distortion is within the elastic limit of the material of the metal strip, the metal strip returns to its original state after passing through the roll, and does not cause permanent set. Therefore, this strain is set to 0.1 <X <0.16 where the elastic limit of this type of metal material exists. The strain x on the outer surface of the metal strip is x = U / E + t
/ 2R, the tension U applied to the metal strip is determined when the roll diameter R is determined, and the optimum value of the roll diameter R is determined when the tension U applied to the metal strip is determined. Can be obtained from the above equation. As a result, when the metal strip is passed through a roll at the time of production, plastic deformation such as bending applied to the metal strip is reduced (including zero), thereby obtaining an optimum curl toyo of the metal strip.

According to a second aspect of the present invention, in the method for controlling the bending of a metal strip according to the first aspect, the metal strip is made of mild steel. According to a third aspect of the present invention, in the method for controlling the bending of a metal strip according to the first or second aspect, an optimum value of X is determined from a value of an elastic limit in a stress-strain diagram of the material. And

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for controlling the bending of a metal strip according to the present invention will be described in detail with reference to the drawings. FIG.
4 is a flowchart illustrating an embodiment of a method for controlling the formation of a curved metal strip according to the present invention. The illustrated method for controlling the bending of a metal strip according to the present invention schematically includes a deflector roll a, a distributing roll g, and a guide roll i of a slitter line that affect the formation of a curled toyo by elastic limit strain X ( %) So as to satisfy 0.1 <X <0.16 (Step 1), and the value of the tension U applied to the above equation. A step (Step 2) of setting the size of the unit tension so that the metal strip J is passed through the slitter line to be cut into a plurality of strips having a predetermined width, and cut by a tension reel (TR). Winding each strip (step 3).

When the metal strip J passes through various rolls, the longitudinal strain x of the outer surface of the metal strip J is expressed by the following equation as shown in FIG. x = U / E + {2 × pi × (R + t) −2 × pi × (R + t / 2)} / {2 × pi × (R + t / 2)} = U / E + (t / 2) ) / (R + t / 2) = U / E + t / (2R + t). Here, since 2R is much larger than t, it can be approximated as = U / E + t / 2R (Equation 1).

Assuming that the elastic limit strain of the material is X, when x in Expression 1 exceeds X, that is, when the following Expression 2 is satisfied,
Plastic deformation occurs due to bending. In other words, if x in Equation 1 does not exceed X, the metal strip J is restored to its original longitudinal length after passing through the roll no matter how many times the metal strip J passes through the roll,
No plastic deformation due to bending is given to the metal strip J. x = U / E + t / 2R ≧ X (Equation 2)

Here, the elastic limit strain X (%) is determined from a stress-strain diagram of the material. 3, the stress at the elastic limit is 317 N / square mm at the offset of 0%, and the strain X (%) at the elastic limit is 0.1 %.
It becomes 14. 4, the stress at the elastic limit obtained from FIG. 3, that is, the elastic limit strain X (%) at 317 N / mm 2 is 0.129.

[Table 3]

[Table 4]

Next, the elastic limit strain X (%) is determined from the change in the roll outer diameter and the curl. Roll outer diameters of 100 mm, 125 mm, 160 mm and 18 when the metal strip thickness is 0.15 mm, 0.20 mm and 0.25 mm
The strain x of 0 mm is obtained from Equation 1 as shown in FIG.

Referring to Tables 1 and 2, and FIG.
Since the deflector roll a (roll outer diameter: 180 mm) has no change in curl in the mild steel metal strip having a plate thickness of 0.20 mm and the curl has changed in the mild steel metal strip having a plate thickness of 0.25 mm, The elastic limit strain X (%) is in the middle,
That is, it is estimated that 0.125 <X <0.151 (formula 3). Here, considering Table 3 and Equation 3,
Assuming that the elastic limit strain X = 0.125 (%), the roll outer diameter that does not affect the curl is determined.

From Equation 2, x = U / E + t / 2R <0.00125, and t / 2R <0.00125-U / E2R> tE / (0.00125EU) (Equation 4). Here, the thickness of the target metal strip is 0.2
Since it is up to 8 mm, it can be considered that t = 0.3 mm.
Then, when this value is applied to Equation 4, 2R> tE / (0.00125EU) = 0.3 × 17653 / (0.00125 × 17653-2.1) = 5295.9 / 19.6662 = 265.2 mm 2, and the roll outer diameter that does not affect the curl is 270 mm
Becomes

(Embodiment) With a roll outer diameter of the deflector roll a set to 270 mm, a metal strip J made of mild steel having a thickness of 0.25 mm was passed through to examine whether or not it affected the curl. For verification, the line was operated by the passing method of A, B and C (see FIG. 5), the line was stopped when the line speed and tension were stabilized, and sampling was performed at positions P1 to P12. Table 5 summarizes the results.

[Table 5]

As can be seen from Table 5, the curl (-) 29
After passing through the deflector roll a having a roll outer diameter of 270 mm, the curl becomes (-) 25 mm and the (+)
It changed by 4 mm. In a conventional line of this kind, a roll having a roll outer diameter of 180 mm was used as the deflector roll a. In this case, the curl change was (+) 27 mm.
Met. Therefore, when the roll outer diameter of the deflector roll a is 270 mm, the change is drastically reduced.

[0022]

According to the method for controlling the bending of a metal strip according to the present invention, the tension U or the roll diameter R applied to the metal strip is adjusted so that the elastic limit strain X (%) becomes 0.1 <X <0.16. Formula X
= U / E + t / 2R, whereby the metal strip is subjected to less than the elastic limit stress when the metal strip passes through the roll, so that the metal strip is subjected to plastic deformation such as bending. Accordingly, there is an effect that an appropriate curl toyo of the metal strip can be obtained by executing an appropriate post-process.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of a method for controlling the formation of a curved metal strip according to the present invention.

FIG. 2 is a cross-sectional view when a metal strip passes through a roll surface.

FIG. 3 is a stress-strain diagram of a mild steel metal strip having a thickness of 0.20 mm.

FIG. 4 is a stress-strain diagram of a mild steel metal strip having a thickness of 0.25 mm.

FIG. 5 is a flowchart for explaining an outline of a conventional metal strip production line.

FIG. 6 is a schematic view of a metal strip slitter line.

FIG. 7: Roll outer diameter 100 m according to metal strip thickness
5 is a graph showing strains x of m, 125 mm, 160 mm and 180 mm.

[Explanation of symbols]

 TR1, TR2 No. 1, 2 tension reel POR pay-off reel S slitter a deflector roll b, c bridle roll d tension roll e wrinkle removing roll f deflector roll g, h distribution roll i, j guide roll

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-77107 (JP, A) JP-A-1-99721 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 1/22 B21D 1/05

Claims (3)

(57) [Claims] When passing through a roll during the production of a metal strip,
In order to reduce plastic deformation such as bending applied to the metal strip, the tension U or the roll diameter R applied to the metal strip is set as follows so that the elastic limit strain X (%) becomes 0.1 <X <0.16. From the formula of the optimal metal strip curl
A method for controlling the bending of a metal strip, characterized by obtaining a toyo. X = U / E + t / 2R where E is the Young's modulus of the metal strip and t is the thickness of the metal strip. 2. The method according to claim 1, wherein the metal strip is made of mild steel. 3. The method according to claim 1, wherein the optimum value of X is determined from a value of an elastic limit in a stress-strain diagram of the material. A method for controlling the formation of a bend.