JP4919857B2 - Manufacturing method of single-sided taper steel plate whose thickness changes in a taper shape in the rolling direction - Google Patents

Description

  The present invention relates to a method for producing a single-sided tapered steel plate whose thickness changes in a taper shape in the rolling direction.

  From the viewpoint of reducing the weight of the structure, reducing the material cost, omitting the welding process, and the like, there is a demand for a steel plate that is rolled so that the plate thickness changes in a taper shape in the rolling direction. As a manufacturing method of this type of steel plate, for example, in Patent Document 1, a taper steel plate that changes the outlet side plate thickness in a taper shape in the rolling direction based on the relationship between the roll gap and the rolling load during flat plate rolling and the predicted rolling load. A plate thickness control method has been proposed. In rolling, since the rolling loads acting on the upper and lower surfaces of the steel plate are equal, what is manufactured by this method is a tapered steel plate having a taper amount substantially equal to both sides as shown in FIG. 1, as shown in FIG. It is difficult to produce a tapered steel plate having a flat single side. However, as a tapered steel plate, a tapered steel plate having a flat one side may be required from the viewpoint of jointability with other members.

Therefore, Patent Document 2 proposes a method of manufacturing a tapered steel plate having two flat taper steel plates of the same size, which are flattened on one side and then taper on only one side after being corrected using a roller leveler. Has been.
JP-A-51-97565 JP 11-169950 A

  With the method proposed in Patent Document 2, a single-sided tapered steel plate can be manufactured in the case of a thick plate that is unlikely to cause shape defects such as buckling. However, when the plate thickness is as thin as 4 mm or less, such as a cold-rolled material, a shape defect such as buckling is likely to occur when a tapered portion on one side of a double-sided tapered steel plate is crushed by a roller leveler. In the case of a thin plate, in particular, the larger the step, the easier it is to cause shape defects such as buckling, and when it has a tapered portion with a step amount of 0.1 mm or more, it is difficult to produce a single-sided tapered steel plate by this method. In addition, this method requires a roller leveler having a powerful reduction mechanism, and it is desired to produce a single-sided tapered steel plate only by a rolling process.

  On the other hand, in recent years, demand for plated steel sheets such as galvanized steel sheets and aluminum plated steel sheets has increased from the viewpoint of corrosion resistance. Even in a tapered steel plate, a plated steel plate may be desired as a material. However, when a plated steel sheet is rolled by the method proposed in Patent Document 1 or Patent Document 2 to produce a tapered steel sheet, the plated layer is damaged on both surfaces of the steel sheet, so the taper covered with a healthy plated layer is used. It is difficult to manufacture a steel plate.

  Also, in the case of a tapered steel plate, unlike a normal flat plate, passing a plating line such as a hot dipping line after continuous forming means that the steel plate having a different thickness in the longitudinal direction is repeatedly bent by a passing plate roll. However, it is difficult from the viewpoints of sheet passing and shape controllability. Furthermore, it is possible to produce a tapered steel plate covered with a sound plating layer by immersing it in a plating bath using a tapered steel plate as a cutting plate, but there is a problem that the production cost is high, which is difficult in commercial production. It is. Therefore, in order to produce a tapered plated steel sheet with high productivity, it is desired to produce a tapered plated steel sheet by rolling the plated steel sheet.

The present invention has been devised to solve such a problem, and provides a method for producing a single-side tapered steel plate having a high thickness and a thin plate only by a rolling process without requiring a roller leveler. For the purpose.
Moreover, even if a material to be rolled is a plated steel plate, it aims at providing the method of manufacturing with high plate | board thickness precision the taper steel plate by which one side is covered with the healthy plating layer.

In order to achieve the object of the method for producing a single-sided tapered steel plate of the present invention, two plates of the same size provided with a plating layer as needed are stacked and rolled at the same time, and then the two plates are separated. When producing rolled taper steel sheets with a flat laminating surface by continuously changing the roll gap in the rolling direction during rolling, the sheet width, contact arc length, material deformation resistance, and rolling mill entry / exit during laminating rolling The rolling load difference between adjacent control sampling points is predicted from the rolling load formula consisting of the unit tension and the rolling force function on the side, and the adjacent control sampling points so that the exit side plate thickness changes in a tapered shape according to the rolling length The roll gap is controlled on the basis of a relational expression established between the rolling load, the roll gap, and the plate thickness of the steel sheet .
It is preferable that the lap rolling is continuously performed using a rolling facility composed of a rolling mill and two sets of reels installed before and after the rolling mill.

The following formulas (1) and (2) are used as relational expressions that hold between the rolling load, the roll gap, and the plate thickness of the steel plate.
S ₀ = h ₀ −P ₀ ^c / M (1)
S _i = S ₀ -1 / M · (P _i-1 -P ₀ ^c ) -1 / M · (P _i ^c -P _i-1 ^c ) · P _i-1 / P _i-1 ^c + Δh _i ( 2)
However, S ₀ : Roll gap at the reference position h ₀ : Target plate thickness at the reference position P ₀ ^c : Predicted rolling load at the reference position M: Mill stiffness coefficient S _i : Roll gap at the sampling point P _i ^c , P _{i− 1} ^c: rolling load prediction value of the sampling point and the previous sampling point P _i-1: rolling load measurement of the previous sampling point of the sampling points Delta] h _i: target delivery side thickness difference with respect to the reference position of the sampling point

In the present invention, the roll gap is continuously changed in the rolling direction in the rolled sheet rolling in which two sheets of the same size are stacked and rolled at the same time. Therefore, the overlapping surface of the steel plates becomes flat, and a single-sided taper steel plate can be manufactured even in the case of a thin plate and a high step only by a rolling process.
Roll roll gap change accuracy can be improved by predicting the rolling load difference between adjacent control sampling points from the rolling load equation during roll sheet rolling. It becomes possible to manufacture a single-sided tapered steel plate having a highly accurate taper thickness accuracy compared to the technology.
If a plated steel plate is used as the material to be rolled, a tapered steel plate whose one surface is covered with a healthy plating layer can be manufactured with excellent taper thickness accuracy.

Embodiments of the present invention will be described in detail below with reference to the drawings.
The present invention is an application of roll sheet rolling, and as shown in FIG. 3, when two steel sheets 1 and 2 having the same size are stacked and rolled, the roll gap is continuously changed and controlled in the rolling direction. Thus, a single-sided tapered steel plate in which the overlapping surface 3 of the steel plates 1 and 2 is flat is manufactured.
That is, if the two steel plates 1 and 2 have the same dimensions, the rolling configuration is basically vertically symmetric, so that the overlapping surface is flat. According to this method, unlike the method proposed in Patent Document 2, it is not necessary to crush the tapered portion on one side of the double-sided tapered steel plate with a roller leveler. This makes it possible to manufacture a single-sided tapered steel sheet without causing any problems.

  When continuously forming the tapered steel plate, as shown in FIG. 4, a laminating machine 9 composed of a rolling mill 4 and two sets of reels 5, 6, 7, 8 installed before and after the rolling mill 4 is used. The coiled steel plates 1 and 2 are paid out from the reels 5 and 6 installed in front of the rolling mill 4, and are wound around the reels 7 and 8 installed after the rolling mill 4 after rolling by the rolling mill 4.

  Next, the inventors of the present invention have various methods capable of producing a tapered steel sheet having a high precision taper thickness accuracy with a thin plate, a high step and a small step height in rolling of the tapered steel sheet. I examined it. As a result, by predicting the rolling load difference between adjacent control sampling points from the rolling load formula, the taper thickness accuracy in rolling high-level tapered steel plates is improved, and thin plates that require strict plate thickness accuracy are required. And it discovered that manufacture of a taper steel plate of a high level | step difference was attained. And the thin plate and the high level | step difference single-sided taper steel plate were able to be manufactured by applying the method to overlap sheet rolling.

  In addition, the present inventors have investigated and studied various rolling methods that can produce a tapered steel plate covered with a healthy plating layer without damaging the plating layer when rolling the plated steel plate to produce a tapered steel plate. . As a result, it has been found that damage to the plating layer is caused by shear deformation due to friction with the rolling roll, rather than being stretched by rolling. If the two plated steel sheets are overlapped and rolled, the plating layer is greatly damaged on the surface in contact with the rolling roll, but the overlapping surface is not subjected to shear deformation due to friction with the rolling roll, so the plating layer is damaged. Found that there is less. Furthermore, if plated steel sheets with the same dimensions are used in the roll-plate rolling, the rolling configuration becomes vertically symmetric, and slippage between the plates is suppressed, so that the plating layer damage on the overlap surface is minimized, and the plating layer on which one side is healthy It has been found that a steel plate covered with can be obtained.

  Therefore, as shown in FIG. 3, when the two steel sheets 1 and 2 having the same dimensions are overlapped and rolled, the roll gap is continuously controlled in the rolling direction, whereby the overlapping surfaces of the steel sheets 1 and 2 are overlapped. A taper-like plated steel sheet is obtained in which 3 is flat and covered with a healthy plating layer. This tapered plated steel sheet cannot be used for applications that require corrosion resistance on both sides, but is effective for applications that require corrosion resistance on only one side.

Hereinafter, an embodiment of the present invention will be described in detail based on a control expression in rolling when manufacturing a tapered steel plate. Regarding the plate thickness control, if two steel plates with a flat overlapping surface and a taper on the other surface are stacked, it is considered to be the same as the plate thickness control of one taper steel plate. A control method when considered as a steel plate will be described.
In addition, as described above, if plated steel sheets having the same dimensions are used as the material to be rolled during the rolling of rolled plates, the rolling configuration becomes vertically symmetric and the slip between the plates is suppressed, so the rolling load of the plating layer on the stacked surface is reduced. Since the influence exerted becomes small, the plate thickness can be controlled in the same manner when the plate material having the plating layer is rolled.

The roll gap S ₀ at the reference position is set by equation (1), where h ₀ is the target plate thickness at the tip that is the reference position, P ₀ ^{C is the} predicted rolling load at the reference position, and M is the mill stiffness coefficient.
S ₀ = h ₀ −P ₀ ^c / M (1)
Then, the roll gap S _i at each sampling point of control is corrected by the equation (2).
S _i = S ₀ -1 / M · (P _i-1 -P ₀ ^c ) -1 / M · (P _i ^c -P _i-1 ^c ) · P _i-1 / P _i-1 ^c + Δh _i ( 2)
Here, P _i ^c and P _i-1 ^c are the sampling point to be controlled and the rolling load prediction value at the previous sampling point, and P _i-1 is the sampling at the previous sampling point to be controlled. rolling load measurement value of the point, Delta] h _i is the target delivery side thickness difference with respect to a reference position of the sampling points are trying to control.

Note that any conventional plate thickness control method is 1 / M · (P _i ^c −P _i-1 ^c ) · P _i-1 / P _i-1 ^c, which is the third term in equation (2). The formula (2) constituting the present invention is based on the rolling load difference prediction value between the points i and i-1 which are adjacent sampling points of control according to the third term. The feature is that the value is corrected. That is, in the method of the prior art, the plate thickness is controlled based on the rolling load prediction value of the sampling point immediately before the sampling point to be controlled, and the sampling point to be controlled and the sampling immediately before that are controlled. While the rolling load difference at a point can be an error factor in the plate thickness control, in the present invention, this rolling load difference is considered in the plate thickness control equation.

Further, (1) In the formula and (2) computation of the rolling load ^{_{P 0 c, P i-1}} c, P i c in the formula, using the formula of Bland & Ford, a rolling load equation of formula such as the Hill . For example, when calculating the rolling load using Hill's rolling load equation, it is expressed by equations (3) to (8).
P = b · L · (k− (σb + σf) / 2) · fp (3)
L = √ (R ′ · (H−h)) (4)
fp = 1.08 + 1.79 · μ · r · √ (1-r) · √ (R ′ / h) −1.02 · r (5)
r = (H−h) / H (6)
R ′ = R · (1 + C · P / (H−h)) (7)
C = 16 · (1−ν ² ) / (π · E) (8)
Here, P is the rolling load, b is the sheet width, H and h are the sheet thickness on the entry side and the exit side of the rolling mill, r is the rolling reduction, R and R ′ are the roll radius and the flat roll radius, k is the deformation resistance of the material, σb and σf are unit tensions on the entry and exit sides of the rolling mill, μ is a friction coefficient, E is a Young's modulus, ν is a Poisson's ratio, L is a contact arc length, and fp is a rolling force function.

In addition, since the plate thickness control method currently performed does not directly use the rolling load prediction value obtained from the rolling load formula, it uses a plastic coefficient Q _i that linearly approximates the rolling load with the plate thickness. The deviation from linearity in the relationship between the rolling load and the plate thickness can be an error factor in the plate thickness control, but since the rolling load is calculated by the direct rolling load formula in the present invention, the predicted error amount of the rolling load is Get smaller.

  FIG. 5 is a block diagram showing a control system for carrying out the method of controlling the thickness of the tapered steel plate based on the equations (1) to (8) when manufacturing the tapered steel plate. In the figure, 11 is a rolling mill, 12 is a work roll, 13 is a reduction device, 14 is a reduction position detector, 15 is a rolling load meter, 16 is a pulse generator that outputs a pulse according to the number of rotations of the work roll 12, and 17. Indicates a thickness gauge, and 18 indicates a material to be rolled. During rolling, the rolling position detector 14 detects the rolling position, the rolling load meter 15 detects the rolling load, and the pulse generator 16 detects the roll peripheral speed, and the rolling gap is adjusted by the rolling reduction device 13 based on these detection results. To do.

19 is a rolling condition input device, 20 is a target plate thickness difference setting device, 21 is a rolling load predictor, 22 is a roll gap setting device, and 23 is a roll gap position control system. Target thickness difference setter 20, based on the rolling length of the rolled material 18 obtained from the number of pulses taken from the pulse generator 16, calculates the target delivery side thickness difference Delta] h _i with respect to a reference position of the sampling points are trying to control This is input to the rolling load predictor 21 and the roll gap setter 22. The rolling length of the material to be rolled 18 is obtained by calculating the plate speed using an advanced rate prediction formula based on the roll peripheral speed obtained from the number of pulses.
Rolling load prediction unit 21, based on the rolling conditions input is input from the target plate thickness difference setter 20 and the target delivery side thickness difference Delta] h _i of the rolled material 18 in the rolling condition input unit 9, Bland & Ford of formula The rolling load prediction values P _i ^c and P _i-1 ^c of the sampling point to be controlled by the rolling load equation such as the Hill equation and the previous sampling point are calculated and input to the roll gap setting device 22. To do.

The roll gap setting device 22 uses the above-described equation (1) based on the target plate thickness h ₀ at the tip as the reference position and the rolling load predicted value P ₀ ^c at the reference position input from the rolling load predictor 21. A roll gap S ₀ at the reference position is calculated and input to the roll gap position control system 23.
Further, in the roll gap setting device 22, the roll gap S _{0 at} the reference position, the rolling load prediction value P ₀ ^{c at} the reference position, and the target exit side plate thickness difference Δh of the material to be rolled 18 input from the target plate thickness difference setting device 20. _i , based on the rolling load prediction values P _i ^c and P _i-1 ^c inputted from the rolling load predictor 21 and the rolling load measurement value P _i-1 at the sampling point immediately before the sampling point to be controlled, The roll gap S _i at each sampling point is calculated using the above equation (2), and this is input to the roll gap position control system 23.

Example 1:
Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
In the overlapping plate rolling equipment 9 as shown in FIG. 4, the rolling was performed using the control system shown in FIG. The coiled plain steel plates 1 and 2 having a plate thickness of 1.8 mm and a plate width of 250 mm were discharged from the reels 5 and 6, respectively, and rolled by the rolling machine 4. The target single-sided taper shape is a thin part plate thickness of 1.0 mm, a thick part plate thickness of 1.5 mm, a thin part length of 100 mm, a taper part length of 300 mm, and a thick part length of 200 mm as shown in FIG. Rolling was repeated into a single-sided tapered shape, and single-sided tapered steel plates 1 and 2 were continuously formed. The rolled single-side tapered steel plates 1 and 2 were wound up by reels 7 and 8.
In the roll rolling, the rolling load P was replaced with the rolling load of a single plate having a thickness equal to the total thickness of the two steel plates, and calculated by Hill's formula. Further, the sampling time in the plate thickness control is controlled at intervals of 20 mm in rolling length.

  As a result of measuring the thickness of the single-sided tapered steel plates 1 and 2 after rolling, it was possible to continuously form a single-sided tapered steel plate almost as intended with an average deviation of 20 μm and a maximum deviation of 40 μm.

Example 2:
A coiled plain steel galvanized steel sheet with a plate thickness of 2.0 mm and a plate width of 250 mm having a plating layer with a layer thickness of about 25 μm is used as the material to be rolled, and the target single-sided taper shape shown in FIG. .2 mm, thick part plate thickness 1.7 mm, thin part length 100 mm, taper part length 300 mm, thick part length 200 mm, rolled into a single-sided taper shape with a total length of 1000 mm in the same manner as in Example 1. Tapered galvanized steel sheets 1 and 2 were manufactured.
As a result of measuring the thickness of the tapered galvanized steel sheets 1 and 2 after rolling, an average deviation with respect to the target value was 25 μm and the maximum deviation was 45 μm, and a substantially single-sided tapered shape as obtained was obtained. As a result of investigating the plating layer, the plating layer was greatly damaged on the surface that was in contact with the rolling roll, but the overlapping surface was less damaged by the plating layer and covered with a healthy plating layer having a thickness of about 15 μm. It was.

Example of double-sided taper steel plate shape Example of shape of single-sided taper steel sheet Schematic diagram of the production of single-sided tapered steel sheets by laminating rolling Schematic of the laminating equipment used in the examples The block diagram which shows the control system of the board thickness control method in manufacture of the taper steel plate of this invention Shape of single-sided tapered steel plate manufactured in the example

Explanation of symbols

1, 2: Steel plate 3: Stacked surface of two steel plates 4: Rolling mill
5, 6: Reel installed in front of the rolling mill
7, 8: Reel installed after the rolling mill 9: Laminate rolling equipment 10: Pulse generator 11: Rolling mill 12: Work roll 13: Reduction device 14: Reduction position detector 15: Rolling load meter 16: Pulse generation Device 17: Plate thickness meter 18: Material to be rolled 19: Rolling condition input device 20: Target plate thickness difference setting device 21: Rolling load predictor 22: Roll gap setting device 23: Roll gap position control system

Claims (4)

When two sheets of the same size are overlapped and rolled at the same time, and then the two sheets are separated, a rolled steel sheet is formed by continuously changing the roll gap in the rolling direction so that the overlapping surface becomes flat. In manufacturing , the rolling load difference between adjacent control sampling points is predicted from the rolling load equation consisting of the plate width, contact arc length, material deformation resistance, unit tension on the entry / exit side of the rolling mill, and the rolling force function. In addition, the rolling load difference between adjacent control sampling points is used as a variable so that the outgoing side plate thickness changes in a tapered shape according to the rolling length, and is based on the relational expression established between the rolling load, the roll gap, and the plate thickness of the steel plate. A method of manufacturing a single-sided tapered steel sheet, wherein the sheet thickness changes in a taper shape in the rolling direction, wherein the roll gap is controlled. The following formulas (1) and (2) are used as a relational expression established between the rolling load, the roll gap, and the thickness of the steel plate. The single-side tapered steel plate having a thickness that changes in a taper shape in the rolling direction according to claim 1 . Production method.
S ₀ = h ₀ −P ₀ ^c / M (1)
S _i = S ₀ -1 / M · (P _i-1 -P ₀ ^c ) -1 / M · (P _i ^c -P _i-1 ^c ) · P _i-1 / P _i-1 ^c + Δh _i ( 2)
However, S ₀ : Roll gap at the reference position h ₀ : Target plate thickness at the reference position P ₀ ^c : Predicted rolling load at the reference position M: Mill stiffness coefficient S _i : Roll gap at the sampling point P _i ^c , P _{i− 1} ^c : Predicted rolling load value at the sampling point and the sampling point immediately before the sampling point P _i-1 : Measured rolling load value at the sampling point immediately before the sampling point Δh _i : Difference of the target delivery side plate thickness relative to the reference position of the sampling point The single-sided taper steel sheet in which the sheet thickness changes in a taper direction in the rolling direction according to claim 1 or 2 , wherein the taper steel sheet is continuously formed using a rolling mill and a rolling facility comprising two sets of reels installed before and after the rolling mill. Manufacturing method. The two plate materials are both plated steel plates. The method for producing a single-side tapered steel plate according to any one of claims 1 to 3 , wherein the plate thickness changes in a taper shape in the rolling direction.