JPS6313763B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a rough rolling method for steel plates.
In general, during rough rolling of steel plates, uneven roll opening degrees, uneven rolling loads on the driving side and non-driving side of the rolling rolls due to temperature unevenness in the width direction of the steel plate, etc. Due to various factors, there is a problem in which the rolled material curves in the width direction, that is, camber occurs.

If this camber is large, the material to be rolled will damage the rolling rolls and guides, and in severe cases may cause damage, causing great damage in terms of time and property. Even if the camber is small, the planned plate size cannot be achieved at the curved portion of the rolled material, and the product yield, that is, the amount of product/raw materials, decreases.

Conventionally, as a means to eliminate plate bending due to the temperature unevenness in the width direction of the steel plate as described above, the difference between the rolling load on the non-driving side and the rolling load on the driving side of the rolling rolls is detected, and the rolling load is adjusted according to this difference. , there is one in which a difference is provided between the roll opening degrees on the non-drive side and the drive side.

However, in hot-rolled thin plate rolling, the plate width is 700 mm.
Because of the narrow width of ~1800 mm, there is a problem that the difference in load between the non-drive side and the drive side of the rolls during rolling is difficult to show compared to thick plate rolling, etc., and control is difficult.

In addition, plate bending occurs only at the tip of the material to be rolled, almost never at the center or tail end in the longitudinal direction, and the rolling speed of the material to be rolled is relatively high (2 to 3 m/sec). However, there is a problem in that it is difficult to control the bending of the plate after rolling has started.

This invention has been made in view of the above-mentioned conventional problems, and includes a method for hot rough rolling of steel plates.
Before starting rolling, measure the temperature difference between both sides of the material to be rolled in the width direction, calculate the rolling load difference in the width direction of the material to be rolled that occurs during rolling based on this temperature difference, and apply the calculated rolling force to the rolling rolls. The above object is achieved by rolling by setting a difference in opening degree in the width direction of the sheet to eliminate the load difference.

That is, in the method for hot rolling a steel plate according to the present invention, before the start of rolling, the roll openings on the non-drive side and the drive side of the rolling rolls are adjusted in advance in accordance with the temperature difference between both sides of the material to be rolled in the width direction. By setting a difference in the width of the plate material, the difference in the rolling load in the width direction of the rolled plate material that occurs during rolling due to the temperature difference is eliminated, thereby suppressing the plate bending at the tip.

The present invention will be described in detail below with reference to the drawings.

First, the principle of the method of the present invention will be explained.

The non-driving side of the rolling roll based on the temperature difference T ₁ − T ₂ between the temperatures T ₁ and T ₂ in the width direction of the rolled plate material heated in the heating furnace before rolling, that is, on the non-driving side of the roll and the driving drive side. The pressure difference ΔP during rolling on the drive side is generally determined from the following equations (1) and (2).

△P=k√△W ………(1) k=kaε ^0.21 ε〓 ^0.13 {exp(3000/T ₁ ) −exp(3000/T ₂ )} ………(2) Here, △P: Pressure difference (Kg) k: Deformation resistance (Kg/ ^mm2 ) R: Roll diameter (mm) △S: Reduction amount (mm) W: Plate width (mm) ε: Strain amount (-) ε〓: Strain rate (1/ sec) T ₁ : Non-driving side plate temperature (〓) T ₂ : Driving side plate temperature (〓) ka: Component correction coefficient (-) When a pressure difference △P occurs between the non-driving side and the driving side of the rolling roll in this way, This causes a difference in roll opening between the non-driving side and the driving side of the rolling roll, which causes the tip of the rolled plate to bend. Figure 1 shows the temperature difference T ₁ between the plate bending amount and the rolled plate material.
−T ₂ relationship is shown.

Therefore, a roll opening difference that offsets the roll opening difference between the non-driving side and the driving side of the rolling roll is set on the non-driving side and the driving side of the rolling roll to correct the opening difference.

This correction amount △h is △h=△P/M……(3) M is Mill constant (Kg/mm) is given by

An example of an apparatus for carrying out the method of the present invention will be described below with reference to FIG.

This device includes a pair of thermometers (non-contact type thermometers, e.g. radiation thermometer) 2A and 2B for measuring the temperature difference between both sides 1A and 1B in the width direction of the plate material 1 to be rolled before the start of rolling. , based on the temperature difference measured by the thermometers 2A and 2B, calculate the rolling load difference in the width direction of the rolled plate material 1 that occurs during rolling, and eliminate the calculated rolling load difference in the plate width direction at the rolling roll 3. A roll opening difference calculation device 4 for calculating the opening difference, and a roll opening device that outputs a signal for setting the roll opening based on the reduction correction amount Δh which is the calculation result of the roll opening difference calculation device 4. Based on the setting signal from the roll opening setting device 5 and the roll opening setting device 5, the rolling roll 3 is driven in its radial direction to set the roll openings b, b+ on the non-driving side and the driving side, respectively. It is configured to include roll opening degree setting drive devices 6A and 6B for setting Δh.

Reference numeral 7 in the figure is a plate width/thickness setting device for outputting rolling conditions such as the plate width and thickness of the rolled material to the roll opening calculation device 4, and 8 is a plate width/thickness setting device for outputting the rolling conditions such as the plate width and thickness of the rolled material 1 to the roll opening calculation device 4. Each shows a pulse generator for detection.

The pulse generator 8 detects the rotation speed of the table roller 9 on which the plate material 1 to be rolled is placed, thereby determining how far the plate material 1 to be rolled has traveled from the tip toward the rolling roll 3 side. is detected and outputted to the roll opening degree difference calculating device 4.

For example, when the maximum line speed is 2 m/sec and it takes about 2 seconds to preset the roll opening, the thermometers 2A and 2B are measured at 2 sec x 2 m/sec from the entrance side of the rolling roll 3. = 4m plus 5m, that is, it is installed 9m in front.

Here, the roll opening degree calculation device 4 includes a thermometer 2
After A and 2B start measuring the temperature from the tip of the rolled plate 1, the position that has progressed 9m is detected by the output signal from the pulse generator 8, and the measurement is performed within about 5m from the tip. The difference between the average values of temperatures is calculated.

Therefore, in this embodiment apparatus, the temperature of both sides 1A and 1B in the width direction of the plate material 1 to be rolled is measured within a range of 5 m from the tip of the plate material 1 to be rolled,
Temperature difference of the average value and the plate width, plate thickness setting device 7
Based on the rolling conditions from , the roll opening difference calculation device 4 calculates the rolling reduction correction amount Δh based on the above-mentioned formulas (1) to (3), and calculates this by the roll opening difference setting device 5.
Output to.

The roll opening difference setting device 5 outputs the roll openings b and b+Δh on the non-drive side and the drive side of the rolling roll 3 based on the output signal of the correction amount Δh from the roll opening difference calculating device 4. The roll opening degree setting signal is outputted to the roll opening degree setting drive devices 6A and 6B, respectively.

The roll opening degree setting drive devices 6A, 6B are based on the output signal from the roll opening degree setting device 5.
The reduction screw is driven by the motor,
Roll opening degrees b and b+Δh on the non-drive side and the drive side of the rolling roll 3 are set. Here, the relationship between the opening correction amount Δh, that is, the rolling reduction difference and the temperature difference T ₁ -T ₂ between the non-driving side and the driving side of the rolling roll 3 is shown in FIG.

When the temperature measurement using the thermometers 2A and 2B is completed, the tip of the plate material 1 to be rolled is 4 m above the rolling roll 3.
Since it is located at the front and there is a time of 2 seconds or more until the roll is bitten, the setting of the roll opening degree is completed before rolling starts.

According to experiments using this device, the amount of plate bending, which currently occurs about 30 to 50 mm, has been reduced to 10 to 0 mm.

Here, the opening difference between the non-driving side and the driving side of the rolling rolls 3, which is set before rolling based on the roll opening difference calculating device 4, cannot be changed until the rolling of the plate material 1 to be rolled is completed. do not have.

This is because, as mentioned above, bending of the plate 1 to be rolled occurs only at the tip, and bending at the center and tail does not occur because the plate 1 to be rolled is pulled by the table. It depends.

For this reason, it is conceivable that a thickness deviation may occur in the width direction of the rolled plate material 1, but this is not a problem because it is uniformly rolled in in the finishing rolling mill in the next step.

In addition, in the present invention, at the stage when the rolling of the tip end of the plate material 1 to be rolled is completed, the rolling roll 3 is
The difference in roll opening between the non-drive side and the drive side may be eliminated so that both openings match.

In this case, there is an advantage that the thickness deviation in the width direction of the rolled plate material 1 after rolling is reduced.

Since the present invention is configured as described above, it has the excellent effect of being able to significantly suppress the bending of the tip of the steel plate during rough hot rolling of the steel plate.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the temperature difference on both sides in the width direction of a rolled plate material and the amount of bending of the tip plate, and FIG. A perspective view including a partial block diagram showing the device;
FIG. 3 is a diagram showing the relationship between the temperature difference on both sides in the width direction of the plate material to be rolled and the rolling reduction difference for correcting the pressure difference due to this temperature difference. 1... Material to be rolled, 1A, 1B... Both sides in the width direction, 2A, 2B... Thermometer, 3... Rolling roll,
4...Roll opening degree calculation device, 5...Roll opening degree setting device, 6A, 6B...Roll opening degree setting drive device, 7...Plate width and plate thickness setting device, 8...Pulse generator.

Claims (1)

[Claims] 1. Before the start of rolling, measure the temperature difference between both sides of the material to be rolled in the width direction, calculate the rolling load difference in the width direction of the material to be rolled that occurs during rolling based on this temperature difference, and apply the calculated amount to the rolling rolls. A hot rough rolling method for steel plates in which a steel plate is rolled by setting a widthwise opening difference to eliminate the rolling load difference.