JPH064168B2 - How to prevent meandering in pinch rolls - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing meandering in a pinch roll in a steel plate manufacturing process or a strip steel plate conveying process.

(Prior Art) Generally, a pair of upper and lower pinch rolls or a plurality of pairs of pinch rolls are installed for the purpose of securing tension during rolling, securing the transporting force of a steel sheet, and the like in a steel sheet manufacturing process or a strip steel plate transporting process.

In this pinch roll, especially when the width of the material is smaller than the width of the pinch roll, meandering may occur due to the camber of the material, uneven plate thickness in the width direction of the material, uneven pressure reduction of the pinch roll, etc. there were. In particular, when the pressure reducing mechanism is hydraulically operated for the reason of increasing the pressure reducing load or improving the operability, it becomes an unavoidable problem.

The easiness of occurrence of meandering becomes more remarkable as the width of the steel sheet is smaller than the width of the pinch rolls or the larger the rolling load is, and, for example, rolling equipment for strip steel sheets or welded pipes is manufactured by roll forming. The hydraulic pinch rolls installed on the inlet and outlet sides of the looper equipment, etc., are particularly prone to meandering when the strip type is a narrow material and when it is necessary to carry out a strong reduction. However, there was a problem that the strip steel was squeezed out from the roll side and the shipment of the strip steel plate could not be continued.

Conventionally, various studies have been conducted on the phenomenon of meandering in a rolling roll when rolling a steel sheet,
For example, a theoretical analysis as described in "Plastic Working Spring Lecture Proceedings of 1985" published by the Japan Society for Plastic Working, 1p is also performed. Further, as measures against this, various meandering correction methods have been proposed, for example, as shown in Japanese Patent Publication No. 58-57247 and Japanese Patent Publication No. 59-16527.

However, these are applied when rolling the material steel plate, and in the case of rolling in the elastic range like a pinch roll, the mechanism of the meandering is basically different from the case of rolling, and measures against it It is impossible to apply as is.

(Problems to be solved by the invention) In a pinch roll, as described above, meandering is caused by uneven thickness in the width direction of the steel plate to be pinched, camber of the edge portion, fluctuation of left and right gaps of the pinch roll, etc. However, there is a problem in that it becomes impossible to stably convey the steel sheet.

(Means for Solving the Problem) In the present invention, among a pair of upper and lower pinch rolls having a hydraulic pressure reduction mechanism, a roll width Wp is set for a width Ws (unit: mm) of a strip steel plate to be pinched. (Unit: mm) is Wp ≧ 2.0
In the pinch roll which is Ws, the crown amount Δc represented by the following formula is set within the range of −15 ≦ Δc · Ws (unit: mm ² ) ≦ 15, and further, the distance L from the center of the pinch roll (unit: m
A pinch roll for restraining the strip steel plate from moving in the width direction and the vertical direction at a position on the pinch roll entrance side such that m) is L / Ws ≦ 20. It is a method of preventing meandering.

Δc = (Dc-De) / 2 where: De: roll diameter of pinch roll end (unit: mm) Dc: roll diameter of pinch roll center (unit: mm) (working) The present invention will be described in detail.

FIG. 1 is a convex pinch roll applied to the present invention, FIG. 2 is an arrangement top view of convex pinch rolls and guide rolls applied to the present invention, and FIGS. 3 and 4 are guides of the present invention. An example of the type of roll, FIG. 5 is a schematic view showing the meandering suppressing function of the concave pinch roll in the present invention, and FIG. 6 shows the experimental results when the meandering is intentionally given.

Usually, during rolling of a strip steel sheet, it is said that due to asymmetrical rolling of the steel sheet and left-right asymmetric rolling due to a camber or the like, a difference in speed between the left and right steel sheets on the entrance side and the exit side of the roll occurs to cause meandering. On the other hand, with pinch rolls, the steel plate is basically only deformed within the elastic range due to rolling, so there is a left-right speed difference in the part in contact with the roll, but the speeds on the inlet side and the outlet side are equal. Has become.

The inventors of the present invention, even if the strip width of the strip steel sheet is narrow or the rolling load is large, due to the slight difference in elongation of the edge within the elastic range of the roll contact portion, as shown in FIG. It was made clear that meandering occurs.

In particular, when the pressing mechanism is a hydraulic type in order to increase the pressing load or to improve the operability, the roll gap fluctuates due to the non-uniformity of the material in the width direction, and thus the meandering is very likely to occur. .

Here, in the present invention, the first
As shown in the figure, the roll shape is preferably convex.
In this case, the contact portion between the roll and the strip steel plate is limited to the vicinity of the central portion of the steel plate and does not contact the edge portion, so that the above-mentioned difference in elongation between the left and right edges hardly occurs, and thus the meandering is reduced.

However, if an excessive amount of crown is given, the meandering force is likely to be generated due to the fluctuation of the roll gap, and the amount of reduction necessary to secure the pinch force becomes large, which causes a problem in rolling the central portion. is there.

Therefore, when the pinch roll is a convex crown roll, the upper limit of the crown amount Δc is set to Δc · Ws ≦ 15 (unit: mm ² ). As a result, the amount of meandering can be considerably reduced.

However, it may not be possible to completely set the meandering amount to 0 due to fluctuations in the roll gap during conveyance of the steel sheet. For this, a side guide roll installed to prevent meandering of the steel plate is effective. Here, in the guide of the type that can prevent the movement in the width direction only, the steel plate may escape in the vertical direction, so the guide is set to be able to prevent the movement in the vertical direction.

Here, FIG. 3 is a type in which side rolls and press rolls are used in combination, and FIG. 4 is a type in which movement in the vertical and width directions is restricted by one roll. The type shown in FIG. 4 is preferable in consideration of the commonality when the width of the pinched steel plate changes and the roll size described later.

Since the position of the guide roll should be as close as possible to the pinch roll, the distance L between the pinch roll and the guide roll was limited to L / Ws ≦ 20.

In order to reduce the distance, it is desirable to reduce the size of the guide roll.

Further, when the guide roll is installed on the exit side of the pinch roll, it basically has no function of preventing meandering, and therefore it is essential to install it on the entrance side of the pinch roll. Further, when the movement of the steel sheet is restrained in this way, it seems that the edge portion of the steel sheet is damaged by the meandering force, which may be caused by setting the distance L between the pinch roll and the guide roll to L / Ws ≦ 20. There is no.

On the other hand, in the present invention, as the pinch roll, it is also possible to apply a concave crown roll or a flat roll instead of the convex crown roll.

In the case of the concave roll, since the contact portion between the roll and the steel plate is limited to the edge portion, the difference in elongation between the left and right is likely to occur, but when the pressure is reduced, the meandering as shown in Fig. 5 occurs. Since the suppressing force works, it is possible to reduce the amount of meandering as a result.

However, when an excessive amount of crown is given, the edge portion is rolled, which causes camber of the steel sheet. Therefore, the lower limit value of the amount of crown is set to Δc · Ws ≧ −15 (unit: mm ² ).

Also in this case, similarly to the case of the convex roll, the installation of the side guide is essential. Further, even when a flat roll is applied, the meandering can be completely prevented by installing the guide roll. However, in consideration of problems such as roll wear, it is most desirable to use a convex roll.

(Examples) Table 1 shows the test results when the present invention is applied and when the strip steel sheet is pinched by intentionally giving a left-right gap difference to generate a meandering force. It is a thing.

Here, the pinch roll having a width of 400 mm was used, the pinch load was kept constant at 4 tons, and the plate width of the steel plate was changed to 50 to 350 mm to carry out the test.

The guide roll types I and II in the table are shown in FIGS. 3 and 4, respectively. −15 ≦
Δc · Wc (unit: mm ² ) ≦ 15 rolls are used, and a guide roll is installed on the entrance side to completely prevent meandering.

(Effects of the Invention) As described above, by applying the present invention, in particular,
It is possible to eliminate the occurrence of meandering on the pinch roll, which is a problem when a narrow width material or strong reduction is required, and it is possible to stably convey the steel sheet.

[Brief description of drawings]

FIG. 1 is a convex pinch roll applied to the present invention, FIG. 2 is an arrangement top view of convex pinch rolls and guide rolls applied to the present invention, and FIGS. 3 and 4 are guides of the present invention. An example of the type of roll, FIG. 5 is a schematic view showing the meandering suppressing function of the concave pinch roll in the present invention, and FIG. 6 shows the experimental results when the meandering is intentionally given. 1. Convex pinch roll 2. Strip steel plate 3. Guide roll 4. Concave pinch roll

Claims (1)

[Claims] 1. A roll width Wp (unit: mm) is Wp ≧ 2.0 with respect to a width Ws (unit: mm) of a strip steel plate to be pinched among a pair of upper and lower pinch rolls having a hydraulic pressure reduction mechanism. W
In the pinch roll that is s, the crown amount Δc represented by the following formula is set in the range of −15 ≦ Δc · Ws (unit: mm ² ) ≦ 15, and further, the distance L from the center of the pinch roll (unit: m
A pinch characterized by installing a guide roll for restraining the strip steel plate from moving in the width direction and the vertical direction of the steel plate at a position on the pinch roll entrance side such that m) is L / Ws ≦ 20. Method to prevent meandering in rolls. Δc = (Dc−De) / 2 where, De: roll diameter of pinch roll end (unit: mm) Dc: roll diameter of pinch roll center (unit: mm)