JPS6356145B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for suppressing width warpage in a strip processing line.

A strip processing line such as a plating line or a continuous annealing furnace is equipped with a large number of rolls, and each time the strip passes through these rolls, it is bent and unbended by the rolls under tension. If all the deformation in this process is elastic deformation, the strip after passing through the rolls will be no different from before passing through the rolls, but if plastic deformation occurs due to bending while passing through the rolls, the strip will warp in width after passing through the rolls. do. Alternatively, if width warpage has already occurred before passing through the rolls, the width warpage changes due to plastic bending when passing through the rolls. Width warpage also occurs when vertically asymmetric rolling is performed (such as rolling at different peripheral speeds, rolling at different diameters on the upper and lower sides, rolling with drive only on one side, etc.). When a strip with such width warpage progresses along the line while passing through many rolls, if the bending as it passes through the rolls is elastically deformed, the width warpage will remain as it is without changing; If the bending is plastic bending, the width warpage will change. In electroplating and other various strip treatments, such width warpage is often detrimental. For example, in the case of electroplating, if there is width warpage as shown in Figure 1, the distance between the strip 1 and the electrode plate 2 changes in the width direction, which causes the plating thickness to change in the width direction. . In order to reduce the non-uniformity of the plating thickness in the width direction, the distance between strip 1 and electrode plate 2 can be increased to bring the value of le/lc closer to 1. This results in an increase in the electrical resistance of the plating liquid between the plate 2 and the plate 2, which requires a large amount of electric power. As in this example, it is often desired to minimize width warpage not only in the final product but also in the processing line. The following description will be made with reference to a vertical electroplating line as shown in FIG.

In Fig. 2, even if the strip 1 on the entry side has no width warpage, if the bending by the energized rolls 3 and sink rolls 4 is plastic bending, width warpage will occur, and each time it passes through the rolls 3 and 4, width warpage will occur. The width warpage changes. As in this example, if the diameters of the rolls 3 and 4 are the same, each roll is bent in the opposite direction, and the work hardening of the material due to plastic bending is very small, each time it passes through the rolls 3 and 4. Width warping of the same size and in the opposite direction occurs.

In this case, if the diameters of the rolls 3 and 4 are increased, the size of the plastic region due to bending will be reduced, and the width warpage of the strip 1 will be reduced. Furthermore, if the diameters of the rolls 3 and 4 are made sufficiently large, only elastic deformation will occur and width warping will not occur, but since increasing the diameter of the rolls 3 and 4 will increase equipment costs, it cannot be made too large. Another measure is to shorten the distance between the upper and lower rolls. This utilizes the effect of restricting width warpage by rolls, which will be explained below.

Even in the strip 1 which is warped in width as shown in FIG. 4, the warpage is zero at the boundary line 6 of contact with the roll 5, and increases as the distance from the roll 5 increases. As shown in FIG. 4a, when the roll is sufficiently far away from the roll 5, the width warpage is no longer restrained by the roll 5, and the width warpage is saturated to become y _nax . Here, the width y of the strip 1 is defined as shown in FIG. If the distance L between the rolls is short, the width warpage y _c at the center of the span will be smaller than y _nax as shown in FIG. 4b. The degree to which y _c becomes smaller than y _nax varies depending on conditions such as plate thickness, plate width, and tension, but in any case, the smaller the inter-roll distance L, the greater the effect. Therefore, as shown in Fig. 2, the shorter the distance between the upper and lower rolls 3 and 4, the smaller the width warpage, but in that case, the electrode plate 2 also becomes shorter, which requires a large number of plating tanks and equipment. Expenses increase. Therefore, the distance between rolls 3 and 4 cannot be made too short.

It should be noted that the deformation when the width warpage changes depending on the distance from the roll 5 as shown in FIG. 4 is usually an elastic deformation. Therefore, in Fig. 4b, the strip 1 is only elastically deformed from immediately after it leaves the upper roll 5 until just before it contacts the lower roll 5', and the occurrence of width warpage occurs vertically with respect to the center of the span. It becomes symmetrical.

As explained above, suppressing width warpage by increasing the diameter of the rolls and shortening the distance between the upper and lower rolls is effective in principle, but there is a problem in that equipment costs increase.

The present invention has been proposed in view of the current situation, and is aimed at suppressing width warpage using an inexpensive method.

According to a first aspect of the invention, there is provided a processing line for applying a longitudinal bend to a running strip, and then applying a longitudinal bend in a direction opposite to said bend, the processing line comprising: As a result of deformation, in a processing line where width warpage of the strip occurs between the point where the first bend is applied and the point where the second bend is applied, the pass line is prevented from changing when the width warp occurs in the strip. A strip width warping method characterized in that the strip is sandwiched between two rolls from both sides, and the rolls are provided with a crown in the opposite direction to the width warpage, thereby deflecting the strip in the opposite direction at the sandwiched position. A method of suppression is provided.

According to a preferred embodiment of the present invention, the amount of crown is controlled according to the amount of warpage of the strip using a variable crown roll.

According to a second aspect of the present invention, there is provided a processing line for applying a longitudinal bend to a running strip, and then applying a longitudinal bend in a direction opposite to the bending, the processing line including plastic deformation due to the first bending. As a result, in a processing line where width warpage of the strip occurs between the point where the first bend is applied and the point where the second bend is applied, the pass line is prevented from changing when the width warp occurs in the strip. Sandwich the strip between two rolls from both sides,
A method for suppressing width warpage of a strip is provided, which is characterized in that the strip is deflected in the opposite direction at the sandwiched position by applying bending to the roll in a direction opposite to the width warpage.

According to a preferred embodiment of the present invention, the amount of bending applied to the roll is controlled in accordance with the amount of width warpage of the strip.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In the case of the vertical electroplating shown in FIG. 2, two intermediate rolls 7 are installed near the center of each span as shown in FIG. At this time, strip 1 should be inserted at a position that does not change the pass line. If it is installed in a position that changes the path line, that is, shifted to the left or right, the strip 1
This is because it causes bending to occur, which in turn increases the width warpage. Even if a flat roll is used as the intermediate roll 7, as shown in FIG. 6, the width warpage is reduced compared to conventional method A (see line B). However, as shown in Fig. 7, the intermediate roll 7 is provided with a crown of an appropriate size in the direction opposite to the width warpage, or as shown in Fig. 8, the intermediate roll 7 is provided with a crown of an appropriate size in the direction opposite to the width warp. When bending is added, the width warpage at the electrode plate position is further reduced as shown in FIG. 6 (see line C). That is,
The width warpage becomes zero at a certain distance from the intermediate roll 7, and the width warpage is quite small before and after that point, so the average width warpage at the position of the electrode plate 2 can be made much smaller than in the case of a flat roll. can.

If the thickness and yield stress of the strip 1 passing through the line change only within a narrow range, the size of the width warping that occurs will not change much, so the crown applied to the intermediate roll 7 and the bending applied to the intermediate roll 7 will vary. It is sufficient to have only one type of fixed value. However, if the plate thickness or descending stress varies over a wide range and warpage of various sizes occurs, it is desirable that the amount of crown or bending applied to the intermediate roll 7 be variable. That is, for example, when a strip 1 with no width warpage passes through,
Since the optimum value for the crown or bending is zero, it is desirable to be able to vary it from zero to the optimum value at the maximum width warpage. When strip 1 is sandwiched between two intermediate rolls 7 so that only the width warpage is changed without changing the pass line (the deformation at this time is also elastic deformation as in the case of Fig. 4), strip 1 is sandwiched. Since the force required for this is very small and therefore the load that the intermediate roll 7 receives is very small, the strength required for the two rolls 7 is quite small. For this reason, the amount of variation can be easily made considerably larger than in the case of variable crown rolls (rolls inflated by hydraulic pressure) or roll bending used in rolling mills. That is, the variable amount can be increased by using a material with a low Young's modulus or by reducing the diameter of the roll (in the case of bending).

In the case of a vertical electroplating line, the present invention can greatly reduce the width warping between the electrode plates 2, so the plating thickness can be made uniform in the width direction, and the thickness can be made uniform to the same extent in the width direction. In some cases, the distance between the electrode plate 2 and the strip 1 can be greatly shortened, resulting in a significant saving in power. Roll diameter
650mm, vertical electroplating with a distance between upper and lower rolls (distance between energizing roll 3 and sink roll 4) of 3.9m, plate thickness 1.6mm, width 1600mm, yield stress 18
When a strip of Kg/mm ² is threaded with a tensile stress of 1 Kg/mm ² , the maximum width warpage at the electrode plate 2 position was 30 mm when the intermediate roll 7 was not used; As a result of applying the present invention using the intermediate roll 7 with a crown of 8 mm, the maximum width warpage at the position of the electrode plate 2 is 4 mm or less, which is about the same level as the flatness defects of the strip such as middle elongation and ear waves. I was held down.

Although the above explanation has been made regarding vertical electroplating, the present invention can also be applied to various other lines, such as hot-dip galvanizing lines, coating lines, continuous annealing furnaces, etc., to greatly reduce width warping in the line. be able to. When the strip is at a high temperature, such as in a continuous annealing furnace, the yield stress is small, so the width warpage becomes large, and as a result, uneven cooling occurs during the cooling process such as gas jet cooling, and flatness tends to deteriorate. Also, by applying the present invention, uneven cooling can be greatly reduced.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the positional relationship between the width curvature of the strip and the electrode plate, Figure 2 is a schematic diagram of a vertical electroplating line, and Figure 3 is a diagram showing the size of the width curvature of the strip. Figure 4 a and b
5 is a diagram for explaining the effect of restraining the width warpage of the strip by rolls, FIG. 5 is a diagram showing the case where the method of the present invention is applied to a vertical electroplating line, and FIG. 6 is a diagram showing the conventional method and the method of the present invention. Figure 7 is a diagram comparing the width warpage of the strip in the case of the invention method. Figure 7 is a diagram showing an intermediate roll with a crown opposite to the width warpage of the strip. Figure 8 is a diagram comparing the width warpage of the strip. It is a figure which showed the intermediate|middle roll which added the direction bending. (Reference number), 1: Strip, 2: Electrode plate,
3: energizing roll, 4: sink roll, 7: intermediate roll.

Claims (1)

[Scope of Claims] 1. A strip processing line that applies longitudinal bending to a running strip and then applies longitudinal bending in the opposite direction to the bending, the processing line comprising: as a result of plastic deformation due to the first bending; In a processing line where width warpage of the strip occurs between the point where the first bend is applied and the point where the second bend is applied, the strip is cut on both sides to prevent the pass line from changing. A method for suppressing width warpage of a strip, which comprises sandwiching the strip between two rolls, and providing a crown opposite to the width warpage on the rolls, thereby deflecting the strip in the opposite direction at the sandwiched position. 2. A method for suppressing width warpage of a strip according to claim 1, which comprises using a variable crown roll and controlling the amount of crown according to the amount of warpage of the strip. 3. A strip processing line which applies longitudinal bending to the running strip and then applies longitudinal bending in the opposite direction to the said bending, wherein the first bending is applied as a result of plastic deformation due to the first bending. If the strip warps in width between the bending point and the second bending point in the processing line, the strip is sandwiched between two rolls from both sides to prevent the pass line from changing. . A method for suppressing width warpage of a strip, characterized in that the strip is deflected in the opposite direction at the sandwiched position by applying bending to the roll in a direction opposite to the width warpage. 4. The method is characterized in that the amount of bending applied to the roll is controlled according to the amount of warpage in the width of the strip.
A method for suppressing width warpage of a strip according to claim 3.