JPH10235405A - Method for controlling dimension of steel shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation in the longitudinal direction of the flange thickness of a product even when dimensional control is applied to only a vertical roll on one side by measuring the rolling load of non-contact vertical rolls and controlling the roll clearance between the side faces of a horizontal roll and the vertical roll based the measured rolling load and deviation of the rolling load. SOLUTION: At a certain time after a material is bitten in a rolling mill, the rolling loads of the vertical roll 2MS on the drive side and the vertical roll 2FS on the operation side are respectively measured with load cells 3MS, 3FS and stored into an arithmetic unit 4 as lock-on values. After this, the rolling loads of the vertical rolls 2MS, 2FS on the drive side and operation side are continuously measured and inputted to the arithmetic unit 4, and differences from the lock-on values about the respective loads of both vertical rolls 2MS, 2FS that is, the deviation of rolling load is determined. By putting this deviation in a prescribed formula, the controlled variable of the roll clearance between the horizontal roll 1 and the vertical roll 2FS is determined and outputted to a reduction controller 5FS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling dimensions of H-section steel, I-section steel, rails and other sections.

[0002]

2. Description of the Related Art Universal rolling is widely used for rolling section steel such as H-section steel. In universal rolling,
By adjusting the roll gap between the horizontal roll and the vertical roll, various types of products can be manufactured. In order to improve the dimensional accuracy of the product, it is necessary to set the roll gap with high accuracy in accordance with changes in rolling conditions.

[0003] It is known that, in universal rolling of a section steel, variation in the product thickness in the longitudinal direction is reduced by AGC (Automatic Dimension Control). For example,
There is an automatic size control method for a section steel disclosed in Japanese Patent Application Laid-Open No. 1-24083. This method considers the relative positional relationship between the horizontal roll and the vertical roll of the universal rolling mill and the elastic deformation of the rolling mill, and estimates the web thickness and the flange thickness from the actually measured values of the load during rolling, The roll nip of each roll is independently controlled to eliminate variations in each thickness. By applying AGC to universal rolling of section steel,
Longitudinal variations in product thickness are reduced.

[0004]

Conventionally, in a universal rolling of a rail, as shown in FIG. 1, a vertical roll is made into a hole type roll so that one vertical roll and a horizontal roll side face are brought into contact (metal touch). Rolling. In this method, the movement of the vertical roll due to the fluctuation of the rolling load is restricted by the horizontal roll,
In the rolling of a section steel by conventional universal rolling, the thickness accuracy can be improved. However, in the case of rolling with a metal touch between the vertical roll and the horizontal roll, dimension control can be applied only to a vertical roll that does not have a metal touch to protect the roll, and the effect of control, that is, an improvement in dimensional accuracy, is about 1/2. become.

[0005] The present invention provides a method for controlling the dimension of a section steel, which can reduce the variation in the flange thickness of a product in the longitudinal direction even when the dimension control can be applied to only one vertical roll. Is an issue.

[0006]

According to a method of controlling the size of a section steel according to the present invention, one vertical roll is brought into contact with the side of a horizontal roll and the other vertical roll is brought into non-contact with the horizontal roll by a universal rolling mill. In the method of rolling steel, the rolling load of the non-contact vertical roll is measured, and the roll gap between the horizontal roll side surface and the non-contact vertical roll is controlled based on the measured rolling load and the following formula. Δs _FS = αΔP _FS / M _COM (1) where Δs _{FS is the} roll gap change amount, α is a constant ΔP _{FS is} the rolling load deviation from the reference condition M _COM = M _FS (M _MS + 2M _T ) / (M _FS + M _MS + 2M _T ) ... (2) M: Mill rigidity, Subscript FS: Non-contact vertical roll side, MS: Contact vertical roll side T: Horizontal roll thrust direction

Here, the above equation (1) showing the control law of rolling according to the present invention will be described. When the load variation ΔP _FS occurs on the non-contact vertical roll side, the following equation (3) is established from the balance of the forces (see FIG. 3). ΔP _FS = ΔP _MS + 2ΔP _T (3) Flange thickness variation Δh on the non-contact vertical roll side at this time
Is represented by the following equation (4). Δh = ΔP _FS / M _FS + ΔP _MS / M _MS (4) Since the contact side vertical roll and the horizontal roll move integrally, ΔP _MS / M _MS = ΔP _T / M _T (5) ΔP _T = ΔP _MS × M _T / M _MS (6) Substituting equation (6) into equation (3), ΔP _FS = ΔP _MS (1 + 2M _T / M _MS ) .. (7) Substituting equation (7) into equation (4), and Δh = ΔP _FS {1 / M _FS + 1 / (M _MS + 2M _T )} (8) Equation (8) {1 / M _FS + 1 / (M _MS + 2M _T )} is introduced as the composite mill rigidity M _COM shown in the above equation (2).
Flange thickness variation Δh on the non-contact vertical roll side, that is, height variation of the section steel, is the load variation ΔP _FS
Only function. Therefore, by controlling the roll gap only on the non-contact vertical roll side in accordance with the control rule shown in the above equation (1), the same control effect as when the roll gap is controlled for the vertical rolls on both sides can be obtained. In other words, the AGC with only one vertical roll can improve the flange thickness accuracy. Even in the case where AGC can be applied to only one side of the vertical roll in a shaped steel (especially asymmetric shaped steel), it is possible to reduce the longitudinal variation of the flange thickness of the product.

FIG. 2A shows a conventional technique, in which the position of the non-contact-side vertical roll is controlled to be constant. For this reason, the movement amount Δ of the horizontal roll with respect to the target flange thickness h _0.
Produces an error corresponding to FIG. 2B shows the present invention, in which the position of the non-contact-side vertical roll, that is, the roll gap between the horizontal roll and the non-contact-side vertical roll is controlled in accordance with the movement amount Δ of the horizontal roll. No error occurs in the thickness h.

[0009] In the above method for controlling the dimension of a shaped steel, the vertical roll contacting the side surface of the horizontal roll is a roll having a hole shape, and the vertical roll on either the working side or the drive side of the rolling mill can be used. Good. The constant α is a control gain for preventing overcompensation, and is usually 0.1 to 1.0.
Range. The rolling by contacting the vertical rolls does not need to be performed in all the passes of the universal rolling, but the rolling may be performed by contacting only necessary passes, and the control of the present invention may be applied.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described by taking as an example a case where a section steel is a rail. Since the demands on the rail dimensions are the strictest in height, only the vertical roll controls the roll gap. In the case of a rail, the legs and the head of the rail correspond to the flange. Since the web width of the rail is determined by the width of the horizontal roll, the height of the rail is determined by the thickness of the legs and the head (flange).

FIG. 3 shows a rail rolling process.
Passes 1 to 14 are for rough rolling, passes 15 to 17 are for intermediate rolling, and passes 17 'to 19 are for finish rolling. Path 15'-17 '
Is edger rolling. The pass 19 is a pass for adjusting the shape, and has a small amount of reduction and does not perform substantial molding.
The dimensional control method of the present invention is applied to the finish rolling of the pass 18. Passes 1 to 14 are rolled by a double rough rolling mill row, and after pass 15, rolling is performed by a universal rolling mill and an edger.

In the above-mentioned rolling pass, in this example, the intermediate rolls 15, 16, 17 and the finish rolling pass 18 control the roll gap. FIG. 4 shows the intermediate rolling passes 16 to
17 schematically shows a universal rolling mill used for the finishing rolling pass 17 and the finishing rolling pass 18.

In the rolling step of the pass 18, the material enters the universal rolling mill shown in FIG. 4 and after a certain period of time, the rolling loads of the driving-side vertical roll _2MS and the working-side vertical roll _2FS are measured by a load meter. Measure at 3 _MS and 3 _FS , respectively. The measurement result of the rolling load is stored in the arithmetic unit 4 as a lock-on value. Thereafter, the rolling loads of the drive-side vertical roll 2 _MS and the work-side vertical roll 2 _FS are measured by a load meter 3 _MS , 3
Measure continuously with _FS . The measurement result is the arithmetic unit 3
, And the difference from the lock-on value for each of the two vertical rolls 2 _MS and 2 _FS , that is, the rolling load deviation ΔP is obtained. When the load deviation ΔP is obtained, the roll interval control amount between the horizontal roll 1 and the vertical roll 2 _FS is obtained by the arithmetic unit 4 according to the equation (1), and the result is obtained by the reduction control unit 5.
Output to _FS . Reduction controller 5 _FS outputs an operation signal to the pressing motor 6 _FS, controls the roll gap. The above series of control operations is repeated until the rear end of the rolled material reaches the finishing universal rolling mill.

In the above description, the roll gap is controlled in the finishing rolling pass.
Roll gaps may be controlled in 6 and 17. The same applies to the case where the roll gap between the horizontal rolls is controlled. Further, the embodiment of the invention has been described by taking the rail as an example, but the present invention is also applicable to a section steel such as an H section steel, an I section steel, and a T section steel.

[0015]

[Example] Rail (JIS 60 kg class, height 174 m)
m, head width 65 mm, leg width 145 mm) were rolled in the rolling process shown in FIG. Rolling results are shown in FIG. 5 by comparing the roll gap control according to the present invention, the roll gap control without the roll gap control, the roll gap control of the contact and non-contact side vertical rolls, and the roll gap control of the contact side vertical roll only.

Without roll gap control, the standard deviation of the height was 0.07 mm. When the roll gap between the contact and non-contact side vertical rolls was controlled, the standard deviation of the height was reduced to 0.02 mm, but cracks occurred on the horizontal roll side surfaces after rolling. When the roll gap of only the contact side vertical roll is controlled (conventional method), the standard deviation of the height is 0.0
4 mm. In the case of the present invention, the standard deviation of the height was 0.02 mm, the same dimensional accuracy as when the gap between the vertical rolls on both sides was controlled was obtained, and no roll damage occurred.

[0017]

According to the present invention, even when the shape and size control can be applied to only one of the vertical rolls, it is possible to reduce variations in the flange thickness of the product in the longitudinal direction. Further, no crack is generated on the side surface of the horizontal roll.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a method for controlling a roll gap in the present invention.

FIG. 2 is a schematic diagram for explaining the reason why an error in flange thickness occurs.

FIG. 3 is a rolling process diagram of a rail to which the present invention is applied.

FIG. 4 is a drawing schematically showing a universal rolling mill used for section steel rolling.

FIG. 5 is a diagram showing an example of rail height variation, comparing a conventional method and a dimension control method of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 horizontal roll 2 vertical roll 3 load cell 4 arithmetic unit 5 reduction control device 6 reduction motor R rolling material Subscript FS indicates non-contact vertical roll side, and subscript MS indicates contact vertical roll side.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fuyasu Yamamoto 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Kazuhiko Saeki No. 1 Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka No. 1 Inside Nippon Steel Corporation Yawata Works (72) Inventor Seitaro Kubo 1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Nippon Steel Corporation Yawata Works (72) Inventor Tokio Kawabata Fukuoka Inside Nippon Steel Corporation Yawata Works, 1-1, Tobata-ku, Kitakyushu-shi, Japan (72) Inventor Yoshitaka Hattori Inside Nippon Steel Corporation Yawata Works, 1-1, Toba-ku, Tobata-ku, Kitakyushu, Fukuoka Prefecture

Claims (1)

[Claims] In a method of rolling a section steel by using a universal rolling mill, one vertical roll is brought into contact with a horizontal roll side face and the other vertical roll is not in contact with the horizontal roll, the rolling load of the non-contact vertical roll is reduced. A dimension control method for a shaped steel, comprising measuring and controlling a roll gap between a horizontal roll side surface and a non-contact vertical roll based on the measured rolling load and the following formula. Δs _FS = αΔP _FS / M _COM where Δs _FS : roll gap change amount, α: constant, ΔP _FS : rolling load deviation from standard conditions M _COM = M _FS (M _MS + 2M _T ) / (M _FS + M _MS +2)
M _T ) M: Mill rigidity, Subscript FS: Vertical roll non-contact side, MS: Vertical roll contact side, T: Horizontal roll thrust direction