JPS59141319A - Method for leveling camber of thick steel plate - Google Patents

Abstract

PURPOSE:To level the flatness and the camber of a hot rolled thick steel plate at the same time by using a roll leveler independently adjustable from left and right draft positions and passing the plate by changing the left and right rolling reductions in accordance with the amount of camber of the plate. CONSTITUTION:A roll leveler to be used is constructed so that left and right draft positions are separately adjustable i.e. the left and right draft positions of an upper work roll 11 are independently adjusted by two sets of lifting motors 6, 7 acting on both ends of the roll 11. In the roll leveler, the difference between left and right rolling reduction for the detected amount of camber is obtained by detecting the bending direction and the amount of camber of a thick steel plate after hot rolling and basing on the relative value of the difference between the left and right rolling reductions and the correcting value of camber, obtained previously and separately for the sheet thickness and the sheet width. The plate is passed through rolls by adjusting the draft positions and the rolling reductions at the left and right sides in accordance with the difference in the rolling reductions.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention solves the problem of camber generated during rolling of thick steel plates.
This invention relates to a method for simultaneously correcting flatness using a roller leveler.

In rolling a thick steel plate, so-called camber, in which the thick steel plate curves in the width direction, may occur during rolling. The causes of camber are: - The thickness of the inlet rolled material is different on the left and right sides, that is, on both sides in the width direction, which is caused by the rolled material, and - Poor parallelism between the upper and lower rolls of the rolling mill. (2) Those caused by the mutual relationship between the rolling mill and the rolled material, such as rolling with the center line of the roll body length of the rolling mill misaligned with the center line in the width direction of the rolled material. can be mentioned.

Conventionally, camber caused by such causes has been corrected by adjusting the rolling positions on the left and right sides of the rolling mill, that is, by rolling with different gaps between the upper and lower work rolls on the left and right sides. However, even if rolling is performed with a predetermined gap difference, the rolling load will fluctuate during rolling due to differences in the shape of the steel plate, temperature differences, or rigidity between the left and right sides of the rolling mill, and the camber cannot be adjusted only by adjusting the rolling reduction and position. It is difficult to completely correct this.

Therefore, it is necessary to roll each plate with a margin in advance so that the width of the plate is sufficiently large, and then cut unnecessary parts to obtain a thick steel plate of the required dimensions, which poses a problem that the rolling yield decreases.

On the other hand, the flatness of thick steel plates is corrected using a roller leveler after rolling. As is well-known, a roller leveler repeatedly bends a steel plate using upper and lower rolls arranged in a staggered manner, thereby reducing internal strain and dividing the steel plate into smaller pieces to create a flat steel plate.
The upper roll can be moved up and down, and the left and right rolling positions cannot be adjusted independently.

This invention attempts to perform the above-mentioned camber correction simultaneously with flatness correction using a roller leveler.The gist of this invention is to use a roller leveler whose left and right rolling positions can be independently adjusted to A method for correcting the camber of a thick steel plate, characterized in that the plate is threaded while changing the amount of reduction on the left and right sides according to the amount of camber.

Hereinafter, this invention method will be explained in detail based on the drawings.

FIG. 1 is a schematic diagram showing a roller leveler, in which (1) shows an upper leveler work roll that can be raised and lowered, (2) shows a fixed lower leveler work roll, and (3) shows a steel plate. In other words, as mentioned above, a normal roller leveler has an upper leveler work roll (1) and a lower leveler work roll (2+ (hereinafter referred to as ``lower work roll (])'', ``upper and lower work roll 2)''). They are arranged in a staggered manner, and the steel plate is repeatedly bent by a number of upper and lower work rolls to reduce internal strain and break it down into pieces, thereby correcting its flatness.

This invention has a mechanism in which the left and right rolling positions of the roller leveler can be adjusted separately, and the camber correction of the steel plate is performed together with the flatness correction.

Figure 2 shows the roller 1/roller whose left and right rolling positions can be adjusted separately.
This shows an example of a scraper, +4) (5j is a lifting mechanism that separately supports both ends of the upper work roll (11), (6)
(7) is a separately driven lifting motor, and (8) is a clutch.

That is, by providing both ends of the upper work roll (11) so that they can be raised and lowered separately using two lifting motors (61+71), a mechanism is created in which the lowering position of the upper work roll (11) can be independently set on the left and right sides. It has become.

FIG. 3 is an explanatory diagram showing an embodiment of the present invention. Conventionally, when correcting the flatness with a roller leveler, the upper and lower work rolls are fed with the same left and right lowering positions, but in this invention, the camber amount is measured in front of the first roller. , find the difference in the amount of left and right rolling of the upper work roll (11) (△ho=h2-h, ) according to the camber amount, and change the rolling position as shown in Figure 3 (a) and (b) to pass through. It is something to be boarded up.

In other words, as shown in Fig. 3(a), the sheet threading direction (arrow direction)
On the other hand, in the case of a right-curved camber, the right side rolling amount of the upper work roll (11) is increased by Δh according to the camber amount to pass the sheet. In the case of a camber curved to the left with respect to the sheet passing direction as shown in Fig. 3(b), the left side rolling amount of the upper work roll (11) is set to △h, according to the camber indication.
This is to make the plate larger and pass it through.

FIG. 4 is a plan view showing a steel plate with camber. From this steel plate (3) to the tip and rear end cropped portion (IT) (1B
) is removed, the length of the center line in the board width direction is L1, and the board width is W
, from the left and right plate ends at the center in the longitudinal direction of the plate to the line segments (chords) connecting the left front and rear ends of the steel plate (3) excluding the cropped portions (IT)' (IB), and the right front and rear ends of the steel plate (3). The dimensions, that is, the plate bending time are △C1, △
Assuming C2, the camber amount is △C=% (△C8 + △C
, ) is defined as

Furthermore, since such camber is caused by a difference in elongation ratio between both ends of the steel plate, there is usually a difference in plate thickness in the width direction. FIG. 5 is a diagram showing a cross section of a T-shaped steel plate where camber occurs. The difference between the plate thickness T and i' at both ends of the steel plate, that is, 'LT' is different from the wedge amount ΔT by 112F.

FIG. 6 is a diagram showing an example of the relationship between the wedge amount and the gamber amount. Figure 6(a) shows the relationship for steel plate thicknesses of 6 to 9*11, and Figure 6(b) shows the relationships for steel plate thicknesses of 9.1 to 19.
, (l mm. In the figure, w1 to w8 are 2000 or less questions and 2000 to 250 questions per steel plate 1', respectively.
0 questions, indicating 2500πM or more. That is, the IJ camber amount is large when the wedge amount is large, and the camber υV becomes large as the steel plate becomes smaller.

As a result of various studies on such camber correction methods, the inventors of this invention used a roller leveler that can adjust the left and right rolling positions separately, and determined the left and right rolling positions and the rolling amount according to the amount of camber. It was discovered that by changing the steel plate and threading it, both ends of the steel plate are stretched, and the camber can be corrected at the same time as the flatness.

FIG. 7 is a chart showing the relationship between the left and right reduction amount difference of the roller leveler and the camber correction amount. The horizontal axis is the difference in left and right reduction kk when the camber is curved to the left and curved to the right (△h = h2-h,
), and the vertical axis is the camber correction amount. All of these relationships apply to steel plate thicknesses of 6 to 9M. In the figure, W1~
W3 is less than 2000 mytt in steel plate, c20
00-2500711i 500M or more. As is clear from the figure, the camber of the steel plate at each thickness and width can be corrected by changing the left and right rolling edges of the roller leveler. That is, by obtaining experimental data in advance for each plate thickness and width as shown in Figure 7, determining the necessary difference in the amount of reduction between the left and right sides according to the amount of camber of the steel plate, and adjusting the reduction position of the roller leveler. , the camber can be corrected.

FIG. 8 is a diagram showing an example of a flow for implementing the method of the invention. This invention first detects the bending direction and camber amount of a steel plate after hot rolling.

Next, the difference in the amount of left and right reduction of the leveler with respect to the detected camber amount is determined from the relationship between the difference in the amount of reduction between the left and right sides determined in advance for each board thickness and width and the camber correction machine. Next, the leveler is instructed to the difference in the amount of reduction between the left and right sides and the position of reduction, the amount of reduction between the left and right sides of the leveler is adjusted, and the leveler is lowered.

Next, embodiments of the invention will be described.

〔Example〕

The camber that occurred in the steel plates of each dimension shown in Table 1 was corrected using the method of this invention and the conventional method (the amount of reduction on the left and right sides is the same).

The roller leveler used was one in which four upper work rolls and five lower work rolls were arranged in a staggered manner, each having a diameter of 275 mm and a length of 4300 mm, and the left and right lowering positions of the upper work rolls could be adjusted independently.

The camber correction effect in this example is also shown in Table 1. In Table 1, e indicates a left-turning kember, and e indicates a right-turning kimber.

As is clear from Table 1, the method of this invention was able to correct flatness and camber at the same time.

As is clear from the embodiment described in Part 1-j-2, according to the method of this invention, the flatness can be corrected and the camber can be corrected at the same time using the roller leveler, so the rolling yield of thick steel plates can be improved. It also has a great effect on quality improvement.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a roller leveler, Fig. 2 is a schematic diagram showing an example of a roller leveler according to the present invention, Fig. 3 is an explanatory diagram showing an embodiment of the invention, and Fig. 4 is a diagram showing how camber occurs. Fig. 5 is a plan view showing the steel plate, Fig. 5 is a cross-sectional view of the steel plate where camber has occurred, Fig. 6 is a chart showing the relationship between wedge 1 and the amount of camber, Fig. 7 is the difference in left and right reduction of the roller leveler and camber. FIG. 8 is a block diagram showing an example of the first flow of implementing the method of the present invention. 1.11...Upper work roll, 2,12...Lower work roll, 3...Steel plate, 4,5...Lifting mechanism, 6,7...
... Lifting motor, 8... clutch. Figure 1 Figure 3 (α) Figure 4 1-cho I'B Figure 5? Fig. 6 Uninon' amount + mml Fig. 7 +1

Claims (1)

[Claims] The left and right rolling positions can be adjusted separately. A roller leveler is used to detect the bending direction and camber of a thick steel plate after hot rolling, and calculate the left and right rolling difference and camber determined in advance for each plate thickness and width. The method is characterized in that the difference in the left and right reduction amounts of the roller leveler with respect to the detected camber amount is determined from the relationship value of the correction amount, and the left and right reduction positions and the third reduction amount are adjusted in accordance with the difference in the reduction amounts, and the sheet is threaded. How to correct the camber of thick steel and plates.