JPH10296311A - Method for controlling thickness of wide flange shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a wide flange shape excellent in the accuracy of thickness by eliminating the variation of flange thickness in the cross section of products in the universal rolling of the wide flange shape. SOLUTION: In the reverse rolling with a universal roughing mill 4, the target thickness to be imparted to rolled shapes at each pass is determined from the difference between the thickness of a rough shape slab and the target thickness of products, the measured thickness of the rolled shapes is measured at a prescribed pass with a hot thickness gage, the correction of reduction is determined in accordance with the difference between the target thickness and the measured thickness at this measuring pass and rolling is executed by correcting the target thickness of the control pass on and after the next of the prescribed pass. Furthermore, in the case there is thickness difference between right and left among flange thicknesses which are detected with the hot thickness gage at four points on the cross section, the positions in the axial direction of horizontal rolls are automatically corrected at the control pass and, in the case there is flange thickness difference between the upper and lower parts among the flange thicknesses at four points on the cross section, the upper and lower pass lines of the horizontal rolls are automatically corrected at the control pass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness control method for controlling the thickness (web thickness / flange thickness) of an H-section steel in hot universal rolling.

[0002]

2. Description of the Related Art FIG.
It is a schematic diagram which shows the hot rolling process of a section steel. Rolled material is
After being heated to a predetermined temperature in the heating furnace 1, it is formed into a crude steel slab by a breakdown mill 2. Next, through the transfer device 3, a plurality of passes of reverse rolling are performed in the rough universal rolling mill 4 and the edger rolling mill 5 to reduce the thickness. Thereafter, finish rolling to a predetermined shape is performed in the finishing universal rolling mill 6 to form a predetermined cross-sectional dimension. After that, it is cut, cooled, straightened and inspected to produce a product.

FIGS. 5 (b) to 5 (d) are schematic diagrams showing a rolling state in each rolling mill in universal rolling. In the coarse universal rolling mill 4, as shown in FIG. 5B, the web and the flange are rolled by horizontal rolls 4A and 4B and vertical rolls 4C and 4D, respectively. In the edger rolling mill 5, as shown in FIG.
By A and 5B, rolling of the flange front end portion which is not pressed is performed. Further, in the finishing universal rolling mill 6, FIG.
As shown in (d), the horizontal rolls 6A and 6B and the vertical rolls 6C and 6D reduce the web and the flange, respectively, and form the flange at a substantially right angle.

When each pass of the above-mentioned universal rolling is performed, the rolling load in the no-load is set such that the rolling load of the pass is predicted and the change in the roll gap due to the rolling load is tightened in advance. doing. However, in the hot rolling of H-section steels, AGC (Au)
Conversion to tomatic gage control was not sufficient in any rolling mill.

As the AGC of a section steel, for example, a control method of actually measuring the thickness of a section being rolled and correcting the rolling schedule of the next pass is disclosed in JP-A-62-93018 and JP-A-62-151214. It is presented in the gazette. In this method, the thickness of the profile (web thickness / flange thickness) is actually measured in a predetermined pass, and the deviation between the target thickness to be given to the profile in each pass and the measured thickness is determined by the horizontal roll and It is corrected by the amount of reduction of the vertical roll.

[0006]

However, in the conventional thickness control method of actually measuring the thickness during rolling and correcting the rolling schedule of the next pass, the conventional roll thickness control method reduces the horizontal roll and vertical roll opening of the universal rolling mill. Since it only expands or narrows according to the amount of correction, the product cross-section may be distorted when the mill stand is incorporated into the roll, or due to the difference in the volume of the flange portion of the coarse steel slab due to uneven material temperature. It is not possible to correct variations in flange thickness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to manufacture an H-section steel having a high plate thickness accuracy by eliminating a variation in flange thickness in a product section. An object of the present invention is to provide a possible thickness control method of an H-section steel.

[0008]

In order to achieve the above object, according to the present invention, when reverse rolling of an H-section steel by a coarse universal rolling mill, the set positions of the horizontal roll and the vertical roll are reduced, and the web thickness and the flange are adjusted. In controlling the thickness, the target sheet thickness to be given to the rolled section in each pass is determined from the difference between the sheet thickness of the rolled section (coarse billet) before rolling and the target sheet thickness of the product. The measured thickness (web thickness / flange thickness) of the profile is measured with a hot thickness gauge, and a reduction amount is determined according to the difference between the target thickness and the measured thickness in this measurement pass. Rolling is performed by correcting the target plate thickness (web thickness / flange thickness) of the control pass subsequent to the predetermined pass by the correction amount, and further, the right and left of the four-point flange thickness in the cross section detected by the hot thickness gauge If there is a flange thickness difference Automatically corrects the axial position of the horizontal roll in the pass, and if there is a difference in flange thickness between the top and bottom of the four-point flange thickness in the cross section detected by the hot thickness gauge, the upper and lower pass lines of the horizontal roll are controlled in the control pass. It is characterized in that it is automatically corrected.

[0009] In the above-described structure, when a rough steel slab roughly rolled by a breakdown mill is rolled in a plurality of passes by a universal rolling mill to produce an H-section steel having a target product thickness, first, the above-described steel sheet is first prepared. Based on the standard rolling schedule taken into account across all passes of the universal rolling mill,
The target thickness of the web and flange to be given to the section steel is determined. Next, the actual thickness of the web and the flange is measured by the hot thickness gauge with respect to the target thickness, and the measured thickness is compared with the target thickness. In the pass or successive passes), the following correction of the roll position is performed. FIG. 4 shows the cross section of the H-section steel, and the thickness of each part is given a symbol as shown in the figure. For convenience, the left side is DS for the flange.
(Drive side) and the right side is WS (work side).

Correction of Web Thickness Difference / Flange Thickness Difference If there is a difference between the target thickness of the web and the actual thickness, the thickness differences Δtw and Δtf between the web and the flange (where the thickness differences are the target thickness and the actual thickness) Is calculated, and the roll gap (opening) correction amount ΔH of the horizontal rolls 4A and 4B is calculated using the following equation (1), and ΔH is calculated in the next control pass.
Is used to automatically correct the roll gap (target web thickness) between the horizontal rolls 4A and 4B. For example, as shown in FIG. 1 (1-a), when the measured thickness of the web is larger than the target thickness, the roll gap between the horizontal rolls 4A and 4B is narrowed using ΔH.

If there is a difference between the target plate thickness of the flange and the measured plate thickness, the difference in thickness between the web and the flange, Δtw, DS above Δtf, DS below Δtf, WS above Δtf, WS below Δtf (target plate thickness−measured plate thickness) Are calculated, and the roll gap (opening) correction amounts ΔV (DS) and ΔV (WS) of the vertical rolls 4C and 4D are calculated using the following equations (2) and (3), and ΔV (WS) is calculated in the next control path. (DS) and ΔV (WS) are used to automatically correct the roll gap (target flange thickness) between the vertical rolls 4C and 4D. Here, when ΔV> 0, the roll gap (opening) of the standard schedule is corrected in the positive opening direction, and ΔV <0
When it is 0, the roll gap of the standard schedule is corrected in the minus direction of the opening. For example, as shown in FIG. 1 (1-b), when the measured plate thickness of the left and right flanges is larger than the target plate thickness, the roll gap between the vertical rolls 4C and 4D is set to ΔV (D
S), narrowing using ΔV (WS).

[0012]

(Equation 1)

[0013]

(Equation 2)

Correction of Difference in Left and Right Flange Thickness When there is a difference in left and right flange thickness, the vertical rolls 4C and 4D are rolled using the above-described formulas (2) and (3) in the same manner as the correction of the flange thickness difference. The clearances (openings) correction amounts ΔV (DS) and ΔV (WS) are obtained, and in the next control pass, the vertical rolls 4 are obtained using ΔV (DS) and ΔV (WS).
Automatic correction of the roll gap (target flange thickness) of C and 4D. For example, as shown in FIG. 1 (2-a), when only the left flange thickness is smaller than the target plate thickness, the degree of opening of the vertical roll 4C of DS is increased using ΔV (DS).

In the case where the above-mentioned correction cannot cope, or in addition to the above-mentioned correction, the following correction is performed. Measured flange thickness tf DS / tf DS / tf WS / tf
Lower WS, flange thickness difference Δtf Upper DS, Δtf Lower DS
.DELTA.tf upper WS..DELTA.tf lower WS (target plate thickness-measured plate thickness)
From the following formulas (4) and (5), the horizontal roll 4
Axial adjustment amounts ΔL (upper) and ΔL (lower) in the axial directions of A and 4B are obtained, and in the next control pass, the axial positions of the horizontal rolls 4C and 4D are automatically determined using ΔL (upper) and ΔL (lower). Fix it. Here, when ΔL> 0, the axis is adjusted in the DS direction, and ΔL <
When 0, the axis is adjusted in the WS direction. For example, FIG.
When the lower right flange thickness is larger than the lower left flange thickness as shown in FIG.
Move to the side.

[0016]

(Equation 3)

Correction of Upper and Lower Flange Thickness Difference When there is a difference between the upper and lower flange thicknesses, the following is obtained from the flange thickness difference Δtf above DS / Δtf below DS / Δtf above WS / Δtf below WS (target thickness−actual thickness). The horizontal roll pass line correction amount ΔP is obtained by using the equation (6), and the pass lines of the horizontal rolls 4A and 4B are automatically corrected using ΔP in the next control pass. Here, when ΔP> 0, the horizontal roll pass line is corrected downward, and when ΔP <0, the horizontal roll pass line is corrected upward. For example, FIG.
When the lower flange thickness is larger than the upper flange thickness as shown in (1), the pass lines of the horizontal rolls 4A and 4B are moved upward by using ΔP.

[0018]

(Equation 4)

Left / Right Flange Thickness Control When there is a difference between the actually measured right and left flange thicknesses, the measured flange thickness tf above DS, tf below DS, tf above WS, tf
From the lower WS, using the following equation (7), the vertical roll 4C,
The 4D opening difference correction amount ΔK is obtained, and the opening of the vertical rolls 4A and 4B is automatically corrected in the next pass.

[0020]

(Equation 5)

According to the above equation, the measurement path (for example, the odd number path)
In the subsequent next pass (even pass) and next pass (odd pass), the gap between the horizontal roll and the vertical roll is automatically corrected, and the horizontal roll is axially adjusted according to the thickness difference between the left and right flanges. By adjusting the position of the upper and lower pass lines of the horizontal roll up and down in accordance with the thickness difference between the upper and lower flanges, variations in the cross section of the left and right and upper and lower flanges are eliminated.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows the thickness control method of the present invention in different cases. FIG. 2 shows a layout of a rolling line for H-section steel and a rough universal rolling mill according to the present invention. FIG. 3 shows a control device for implementing the control method of the present invention.

In the rolling line shown in FIG. 2A, a hot thickness gauge 7 is installed at a stage subsequent to the coarse universal rolling step of the multi-pass reverse rolling including the rough universal rolling mill 4 and the edger rolling mill 5. As the hot thickness meter 7, a γ-ray sensor, a laser distance meter, or the like can be used, but a laser distance meter system capable of measuring a web thickness, a flange thickness, and the like with a large number of laser distance meters is employed.

In FIG. 2B, the coarse universal rolling mill 4 has horizontal rolls 4A and 4B and vertical rolls 4C and 4C.
The horizontal rolls 4A and 4B are rotatably driven by a rotary drive device via a transmission shaft. Vertical roll 4
C and 4D are non-driving rolls. Horizontal roll 4
A and 4B can be moved up and down by a drive unit 8 for up and down movement, and can be moved horizontally by a drive unit 9 for horizontal movement. The vertical rolls 4C and 4D can be horizontally moved by a horizontal movement driving device 10, respectively. Each driving device is driven by a motor, a screw rod, or the like, and is feedback-controlled by a position detector.

As shown in FIG. 3, the hot thickness gauge 7 measures a web thickness, a flange thickness, and the like in a predetermined pass (for example, each odd-numbered pass), and outputs the measured values to the arithmetic unit 11. In addition, the control device 11 receives a path schedule from a process computer or the like as a host computer, obtains a deviation between the target plate thickness of the web flange and the actually measured plate thickness, and, according to the deviation, obtains the aforementioned (1). (6), the horizontal rolls 4A and 4B and the vertical rolls 4C and 4D are adjusted in the next pass (even pass) or the next pass (odd pass) of the measurement pass as shown in FIG. In addition, the difference between the opening degrees of the vertical rolls 4C and 4D is corrected by the equation (7) to control the thickness of the web and the thickness of the flange.

If there is a deviation between the target plate thickness and the measured plate thickness in the web thickness in the measurement pass, the web target plate thickness in the control pass is corrected by ΔH using equation (1). If there is a deviation between the target plate thickness and the measured plate thickness in the flange thickness in the measurement pass, or if there is a difference between the left and right flange thicknesses, (2), (3)
Using the equation, the target flange thickness of the control path is set to ΔV (D
S), and correct by ΔV (WS). Furthermore, when there is a difference between the left and right flange thicknesses in the measurement pass and the correction cannot be used, or in addition to the correction, (4) and (5)
Using the formula, the upper horizontal roll 4A or the lower horizontal roll 4B is moved in the axial direction by ΔL (upper) and ΔL (lower). If there is a difference between the upper and lower flange thicknesses in the measurement pass, the pass lines of the horizontal rolls 4A and 4B are moved up and down by ΔP.

Table 1 shows that H400 × 200 × 8/13 and H
In the rolling of 700 × 300 × 13/24, when the thickness control of the present invention was performed and when it was not performed, the accuracy of the product flange thickness (product target thickness−measured thickness (average of four flange thicknesses in cross section) This is an example in which a comparison is made between the value)) X and the variation (the deviation between the average value of the four flange thicknesses in the cross-section and the individual flange thickness) of the four flange thicknesses in the cross-section.

In the embodiment with control at H400 × 200 × 8/13, among the rolling of all 11 passes, the seventh,
The thickness control of the present invention was performed in 9, 10, and 11 passes. Specifically, in the seventh pass, the thickness difference between the upper and lower flanges ((tf
In order to eliminate (S + tf upper WS) <(tf lower DS + tf lower WS)), the horizontal roll pass line is moved upward (see FIG. 1 (3)), and the right and left flange thickness difference (tf) is obtained in the ninth pass.
In order to eliminate the lower DS <tf lower WS), set the lower horizontal roll to W
It was moved to the S side (see FIG. 1 (2-b)), and the horizontal roll gap and the vertical roll gap were controlled in the tenth pass and the eleventh pass in order to eliminate the deviation between the target thickness and the measured thickness in the web and the flange. (See FIG. 1 (1)).

In the embodiment with control in H700 × 300 × 13/24, of the rolling of all 17 passes,
Move the horizontal roll pass line up and down in the pass,
In the thirteenth pass, the horizontal roll was moved in the axial direction (axial tone), and in the fifteenth and seventeenth passes, the horizontal roll gap and the vertical roll gap were controlled.

As is clear from Table 1, by performing the thickness control of the present invention, the accuracy X of the product flange thickness is improved, and the variation σ of the flange thickness in the cross section is reduced as compared with the case without control. And good results could be obtained.

[0031]

[Table 1]

[0032]

As described above, according to the present invention, when the H-section steel is reverse-rolled by the rough universal rolling mill, the amount of rolling reduction is determined in accordance with the difference between the target plate thickness and the measured plate thickness in a predetermined measurement pass. Rolling is performed by correcting the target plate thickness of the control pass subsequent to the predetermined pass by the rolling correction amount, and furthermore, the four side flange thicknesses in the cross section detected by the hot thickness gauge are changed to right and left flanges. If there is a thickness difference, the axial position of the horizontal roll is automatically corrected in the control path, and if there is a flange thickness difference above and below the four-point flange thickness in the cross section detected by the hot thickness gauge, the control path Since the upper and lower pass lines of the horizontal roll are automatically corrected, the following effects can be obtained.

That is, in the conventional thickness control, the thickness of the flange in the cross section of the product may be caused by a deviation at the time of assembling the roll of the mill stand or a difference in the volume of the flange portion of the rough steel piece due to uneven material temperature. Although it is not possible to correct the variation, in the present invention, the product is manufactured by moving the horizontal roll of the universal rolling mill in the axial direction and moving the horizontal roll pass line in the vertical direction according to the measured web thickness and flange thickness. Variations in flange thickness within the cross section can be eliminated, and an H-section steel with good plate thickness accuracy can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a rough universal rolling mill showing a thickness control method of the present invention.

FIG. 2A is a schematic plan view showing a layout of a rolling line in the present invention, and FIG. 2B is a schematic front view showing a rough universal rolling mill used in the present invention.

FIG. 3 is a block diagram of a control device for implementing the control method of the present invention.

FIG. 4 is a front view showing an H-shaped steel in rough universal rolling.

FIG. 5A is a schematic plan view showing a layout of a general H-beam rolling line, and FIGS. 5B to 5D are schematic front views showing respective universal rolling mills.

[Description of Signs] 1 ... Heating furnace 2 ... Breakdown rolling mill 3 ... Transfer device 4 ... Rough universal rolling mill 4A ... Upper horizontal roll 4B ... Lower horizontal roll 4C ... DS side vertical roll 4D ... WS side vertical roll 5 ... Edger Roller 5A: Upper edger (groove type) roll 5B: Lower edger (groove type) roll 6: Finishing universal roll 6A: Upper horizontal roll 6B: Lower horizontal roll 6C: DS side vertical roll 6D: WS side vertical roll 7 ... Hot thickness gauge 8 ... Driving device for vertical movement of horizontal roll 9 ... Driving device for horizontal movement of horizontal roll 10 ... Driving device for horizontal movement of vertical roll 11 ... Calculator

Claims (1)

[Claims] 1. A reverse universal rolling mill for reverse rolling of an H-section steel, in which a horizontal roll and a vertical roll are reduced in a set-down position and a web thickness and a flange thickness are controlled. From the difference between the target product thickness and the product, determine the target thickness to be given to the rolled profile in each pass, measure the actual measured thickness of the rolled profile in a predetermined pass with a hot thickness gauge,
A rolling reduction amount is obtained according to a difference between the target plate thickness and the measured actual plate thickness in this measurement pass, and the target plate thickness of a control pass subsequent to the predetermined pass is corrected by this rolling correction amount to perform rolling. If there is a flange thickness difference between the left and right of the four-point flange thickness in the cross section detected by the hot thickness gauge, the axial position of the horizontal roll is automatically corrected by the control path, and the hot thickness gauge is used. A thickness control method for an H-section steel, comprising automatically correcting the upper and lower pass lines of a horizontal roll in a control pass when there is a difference between upper and lower flange thicknesses among the four-point flange thicknesses in the cross section detected in the step.