JPS5930488B2 - Universal rolling method of section steel with different flange thickness using offset method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention aims to improve the roll gap in 40-rule universal rolling with vertical rolls, especially in universal rolling of sections with different thicknesses at flange portions, such as rails and H-sections of unequal thickness. It is related to setting and adjustment control, and its purpose is to compensate for the shortcomings of the conventional technology and to efficiently obtain products with good shape and dimension accuracy.

It is well known that the universal rolling method is used for rail and H-shape rolling.

force, 1 This method uses four vertical rolls (upper and lower horizontal rolls and left and right vertical rolls) to form the groove, compared to the conventional groove rolling method, which uses only two upper and lower horizontal rolls.
．． Although there is a large degree of freedom in adjusting the roll gap to obtain a desired product shape, the roll gap adjustment and adjustment is also complicated and difficult because the roll displacement is complicated.

Therefore, if these roll displacements are not appropriately dealt with, the deviation from the desired product shape will be significant and the energization efficiency will be reduced.

□In the case of universal rolling of rails and H-beams of unequal thickness, since the left and right sides are asymmetrical, a force in the so-called thrust direction, that is, a thrust force, acts in one direction, especially on the upper and lower horizontal rolls. Therefore, positional displacement in the thrust direction, that is, thrust displacement arise.

This thrust displacement (the shape of the rolled material may deviate from the original intended shape, i.e., the design shape), resulting in a difference in product shape and dimensions (which is a very serious problem that not only reduces the shape but also reduces work efficiency). It has major drawbacks.

This will be explained in detail with reference to the diagram.

Figure 2 is a well-known groove diagram for universal rolling of rails.

In Figure 1, in the case of a rail, the head side width W1 is the foot side If
14W2 is stronger, so the head side vertical roll reaction force P,
The vertical roll reaction force P2 on the foot side is larger, and this fear acts as a thrust force, that is, Px, on the horizontal roll 1.
j, 2 is displaced from the foot side to the head side as shown by the dotted line -O\:ru.

If such thrust displacement occurs, the shape and dimensions of the rolled material will deviate from the design target shape and dimensions.

Now, for example, if a thrust displacement occurs, the deviation of the shape I method in this hole shape is determined by the head thickness tl and the foot thickness t.
2, tl becomes smaller by ΔS and t2 becomes larger by ΔS.

If such a deviation from the design target value occurs, the shape of the product will change even though it is usually rolled in several holes before it is finished.
This greatly affects dimensional deviations and results in defective products.

In addition, the bending changes due to the difference in the amount of reduction between the head and the foot, causing the guide to hit the guide and reducing work efficiency.

In this way, in rail universal rolling, thrust displacement is an important point in determining the shape, and how to deal with this displacement is related to the success or failure of rolling by this method.

In contrast, the vertical roll and horizontal roll on the head side are brought into contact,
That is, there is a so-called metal touch method, which reduces the thrust displacement by setting the head-to-vertical roll gap to 0 and stopping the thrust force from being received by the vertical rolls.

This method is possible in the case of 1 stand and ■pass, but
It is clear that this method cannot be applied to the conventional universal rolling method of one stand, two passes or more.

Therefore, thrust displacement has conventionally been dealt with in the following manner.

The first is to strengthen the thrust force receiving structure of the horizontal roll.
This is a method of increasing the thrust mill rigidity and reducing the thrust displacement to a negligible level.

However, unlike the structure in the radial direction, the structure in the thrust direction is complex with many components, and the force transmission path is long, so it is not possible to increase the rigidity.

For example, the results of a survey at a certain stand show that the mill stiffness coefficient in the radial direction: My = 250 ton 7 mm, and the stiffness coefficient in the thrust direction: My = 35 to
n 7mm, which is approximately %, which is extremely small.

Furthermore, the thrust force receiver mechanism requires the horizontal roll to move up and down according to the pass schedule in each pass, so there is a gap in the thrust direction, and there is a possibility of backlash due to the clearance of the thrust bearing, the gap between each part, etc. exists.

The amount of play reaches 1r/L71 or more.

Therefore, it is very difficult to eliminate thrust displacement using this method.

The second method is based on the hole design.

In other words, the amount of head rolling is made extremely large compared to the amount of rolling at the foot, and the difference between the vertical roll rolling reaction force at the head and the vertical roll reaction at the foot is made as small as possible in order to reduce the generation of thrust force itself. This is the way to do it.

However, in order to reduce the rolling reaction force difference between the vertical rolls to zero using this method, it is necessary to make an extreme difference in the amount of rolling reduction, which is practically impossible.

Therefore, even with this method, thrust displacement cannot be eliminated.

As described above, it is said that it is practically impossible to eliminate the thrust displacement of the horizontal rolls in universal rolling of rails.

Therefore, in the past, methods 1.2 were combined to reduce the pole thrust displacement, and the generated thrust displacement was dealt with by adjusting the thrust setting position of the horizontal roll in the opposite direction of the thrust displacement. .

By such a method, the shape of the hole during rolling can be made as per the design target, and the shape and dimensions of the rolled material can be obtained as the design target.

However, as mentioned before, the thrust position adjustment work takes a long time and requires a lot of labor because the thrust-related mechanisms of ordinary section steel rolling mills are complex.

In addition, the magnitude of thrust displacement originally varies depending on each pass and also differs between each material, but as described above, it takes a long time and requires a lot of effort, so the thrust position is adjusted for each material and each pass. Therefore, it is extremely difficult to set the optimum position for each hole type.

Furthermore, the adjustment must be made for the upper and lower rolls, which requires a great deal of labor and time, and it is extremely difficult to perform the same thrust adjustment amount for the upper and lower rolls.

Furthermore, although thrust displacement is dealt with by the above-described method, another problem with the conventional method is that the amount of thrust position adjustment cannot be accurately determined.

In conventional section steel rolling mills, position detection devices in the thrust direction of the horizontal rolls were not installed because they were not carried out frequently and were not important, as in universal rolling of rails, or even if they were installed, they were not installed to detect the position of the horizontal rolls in the thrust direction. It was only possible to detect the position of the track receiving box.

Therefore, it is not possible to detect the thrust position with high accuracy (
There was no way to know the thrust position during rolling.

For this reason, thrust position adjustment in the past has been done by trial and error while checking the shape and dimensions of the rolled material or product in that hole shape.

As a result, the accuracy of thrust position setting is poor, resulting in defects in product shape and dimensions, and the number of thrust adjustment operations is increased, resulting in a decrease in efficiency and yield.

As described above, it can be said that if a method to deal with such problems is added to the conventional rail universal rolling, ideal rolling will become possible for the first time.

The present invention provides a universal rolling method that makes it possible to easily and accurately set and control the thrust displacement of horizontal rolls, which has a serious adverse effect that cannot be prevented in rail universal rolling.

The gist of the method is to detect the thrust displacement of the horizontal roll, the head side vertical roll rolling reaction force and the foot side vertical roll rolling reaction force,
It is detected from the relationship curve between the vertical roll rolling reaction force difference and the horizontal roll thrust displacement, which has been determined in advance using these vertical roll reaction force differences, that is, the thrust force applied to the horizontal roll in the horizontal roll thrust direction is By using the roll reaction force difference, a gauge meter type is applied to detect the thrust position of the horizontal roll.

On the other hand, by determining the radial position of the vertical roll using a reduction screw position detection device and a vertical roll rolling reaction force meter using a conventional cage meter, the relative relationship between the horizontal roll and the vertical roll, that is, the head vertical roll gap, can be determined. Universal rolling of rails is performed by detecting the vertical roll gap on the foot side, comparing its value with the design target value, and correcting the deviation by adjusting the radial position of the vertical rolls instead of adjusting the melast position of the conventional horizontal rolls. It is the law.

In addition, this is a method in which the rolling reaction force of the head side vertical roll and the rolling reaction force of the foot side vertical roll are predicted by a model formula, and the head side vertical roll gap and the foot side vertical roll gap are set as described above.

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

First, as a result of investigating the thrust displacement of such horizontal rolls using a special instrument, it was found that this is related to the difference in rolling reaction force between the head side vertical roll and the foot side vertical roll rolling reaction force.

This means that although the horizontal roll thrust receiver mechanism is made up of various parts, each of them deforms elastically when force is applied to them, so ultimately it can be regarded as one elastic body, and the reaction force of the vertical roll This means that the difference acts on this and causes thrust displacement.

Therefore, if these relationships are determined in advance, the thrust displacement of the horizontal rolls, that is, the position in the thrust direction, can be detected from the vertical roll rolling reaction force difference.

The relationship between the vertical roll reaction force difference and the thrust displacement can also be determined from the relationship between the reaction force difference and the thrust displacement during rolling, but even if it is not during rolling, it is also possible to move the horizontal roll in the thrust direction with the vertical roll while it is stopped. It can also be determined by applying a thrust load and determining the relationship between the thrust load and the thrust displacement.

An example of the results of this investigation is shown in Figure 2.

On the other hand, if the influence of the thrust displacement of the horizontal rolls and the rolling reaction forces on the head and foot sides of the vertical rolls is considered with reference to FIG. 1, the following results will be obtained.

In Figure 1, when the roll position is set according to the design target (△5-0 as shown by the solid line), the rolling reduction amount is △t towards the head.
1, foot side Δt2.

Normally, △11>△t2, but since the respective widths are W2>Wl, the vertical roll reaction force is P2>Pl
As mentioned above, the difference Px = P2 - P acts as a thrust force on the horizontal roll, causing the horizontal roll to undergo thrust displacement.

If we consider the case where rolling is performed at a position where the horizontal roll has a thrust displacement of △S with the point of all design values (0 adjustment point) as 0, the rolling amount on the head side will increase by △S and the rolling amount on the foot side will increase by △S. Since the reduction amount is reduced by ΔS, the reaction force Pl is large, P2 is small, and the difference Px between them is small.

In other words, Px becomes smaller as S increases, and can be summarized by the curve ``■'' shown in FIG.

This curve will be referred to as the thrust plasticity characteristic curve.

Since the sum of reaction forces during rolling in a steady state is 0, the thrust force exerted on the horizontal roll by the material and the thrust force exerted on the horizontal roll by the thrust receiver of the rolling mill should be equally balanced. .

In other words, the position of the horizontal roll is determined by the intersection of the thrust plastic characteristic curve and the thrust mill stiffness curve, and by using these two curves, the roll position in the thrust direction can be determined using a thrust direction gauge meter. .

This relationship is shown in FIG.

The vertical axis represents the magnitude of the force exerted in the thrust direction, and the horizontal axis represents the position in the horizontal roll thrust direction.

The zero point on the horizontal axis is the design target position.

If the horizontal roll is set to 0 point, the head side vertical roll reaction force,
The horizontal roll undergoes thrust displacement due to the difference in the reaction force of the vertical rolls on the foot side, and the force exerted on the roll by the thrust receiver increases along the curve (■).

On the other hand, the magnitude of the thrust force decreases along the curve (■) due to the thrust displacement, and rolling is performed at a point where these forces are balanced, that is, a.

In this case, a thrust displacement of S1 has occurred with respect to the design target, and this amount alone causes the dimensions to be out of order.

Therefore, in order to obtain the shape that meets the design target, the intersection of the thrust mill stiffness curve ■ and the thrust plasticity characteristic curve ■ must be 0.
It is only necessary to set the horizontal roll by displacing the setting position of the horizontal roll by S2 in one direction as shown by the curve (2) so that the horizontal roll becomes a point.

In this method, there is no device to accurately detect the thrust position of the horizontal roll, there is a large backlash, so it cannot be done accurately and requires labor, and furthermore, it cannot be performed between passes and cannot be performed optimally. said.

Therefore, as a countermeasure to these problems, the position of the vertical rolls is adjusted so that the relative relationship between the horizontal rolls and the vertical rolls meets the design target, and the shape of the hole is obtained as designed.

That is, the head side vertical roll gap Th is increased by the size of S2, and the foot side vertical roll gap Tb is decreased (FIG. 5).

In this way, the one-type gauge meter used in the radial direction in plate rolling is applied to the thrust direction using the reaction force difference between the vertical rolls.

In a normal universal stand, the position of the vertical roll can be adjusted in the same direction as the radial direction of the horizontal roll, and since the position detection device is also equipped, the position can be detected with high accuracy, which improves the accuracy of roll setting.

Moreover, it is easy to perform and saves labor.

FIG. 5 is a schematic diagram showing an embodiment of the rolling method according to the present invention.

As shown in the figure, the respective reaction forces of the positions of the upper and lower horizontal rolls 1 and 2 in the thrust direction are detected by a head-side vertical roll reaction force meter 9 and a foot-side vertical roll reaction force meter 10, and the difference is used to calculate the It is determined from a curve of the relationship between the thrust displacement of the horizontal roll and the reaction force difference, that is, a thrust-5 rigidity curve, which is stored in the control device 17 and determined in advance.

On the other hand, the positions of the vertical rolls 3 and 4 are determined using vertical roll reaction force gauges 9 and 10 and reduction screw position detectors 13 and 14 in the same manner as the radial gauge meter method used in ordinary plate rolling.

In this way, the relative positional relationship between the horizontal roll and the vertical roll, that is, the head vertical roll gap Th and the foot vertical roll gap Tb is detected.

This value is compared with the design target value by the computer control device 17, and based on the deviation, the vertical roll position adjustment devices 15, 16
By operating the reduction screw 1L12, the vertical roll gaps Th and Tb are controlled to the designed target values.

In addition, in the present invention, the shape, bending, and dimensional variations of the rolled material are detected by the shape detection end 18, and correction values for these are calculated using a mathematical model built into the computer control device 17. A coupled automatic shape control is also possible.

The above has described the control method in the thrust direction, but
Control of the position of the horizontal rolls in the radial direction, that is, the horizontal roll gap T, is also carried out using the gauge meter method used in the radial direction of plate rolling, and it is also possible to perform comprehensive roll position control in universal rolling in combination with this method. I can do it.

Furthermore, the rolling method according to the present invention can be applied not only to rail universal rolling but also to other 40-rule universal rolling methods having vertical rolls, and exhibits extremely excellent effects.

[Brief explanation of drawings]

Figure 1 shows a general universal rolling method to explain the present invention, Figure 2 is a chart showing the relationship between the reaction force difference of vertical rolls and thrust in universal rolling, and Figure 3 shows the thrust plasticity characteristic curve. FIG. 4 is a diagram illustrating thrust changes in consideration of the thrust plasticity characteristic curve and the thrust mill stiffness curve, and FIG. 5 is a diagram showing an embodiment of the present invention.

Claims (1)

[Claims] 1. When rolling rails and H-section steel with flanges of unequal thickness using a universal rolling mill, the thickness of the section steel (the rolling reaction force of the vertical rolls rolling the flange side and the thin flange side) The difference between the rolling reaction force of the vertical rolls that roll the roll is detected, and from the relationship between the rolling reaction force difference determined in advance and the axial displacement position of the horizontal rolls from the no-load state to the loaded state, as described above, Based on the rolling reaction force difference between the two vertical rolls detected by the method (calculate the amount of displacement in the axial direction of the horizontal roll), adjust the relative positions of the horizontal roll and both vertical rolls under load so that they match the design values. A universal rolling method for steel sections with different flange thicknesses, which is characterized by pre-offsetting the position of the horizontal roll and the position of the horizontal roll.