JPS5976608A - Method for controlling shape of pipe by reeler - Google Patents

Abstract

PURPOSE:To control highly accurately a shape of pipe rolled by a reeler, by adjusting a torque difference between motors for driving both rolls by field adjusting relatively roll driving motors for driving rolls respectively to adjust the torque difference of the motors for driving both rolls, and controlling the expanding rate of a blank pipe. CONSTITUTION:A blank pipe 14 is reeler-rolled by a plug 13 and two rolls 11, 12 in a state that the pipe 14 is supported at three points by the rolls 11, 12 and a shoe 15, by deviating the pass line of blank pipe 14 from a minimum roll gap position fixed by the center axes of the two rolls 11, 12. At that time, a torque difference between motors 11A, 12A for driving both rolls is adjusted by field adjusting relatively both motors 11A, 12A for driving respectively both rolls, thereby an expanding rate of the pipe 14 is controlled.

Description

[Detailed description of the invention] The present invention relates to a tube shape control method using a reeler.

FIG. 1 is a process diagram showing the manufacturing process of a seamless steel pipe using a general plug mill method. The material heated in the heating furnace 1 is pierced and rolled in a piercer 2, expanded and rolled in an elongator 3, rolled in a plug mill 4 to a thickness equal to the thickness of the solid product, and internally rolled in reels 5A and 5B. The outer surface is polished and finished to a predetermined outer diameter at Side Day 6 to become the final product. In addition, the pipe manufacturing efficiency of each of the above rolling mills (on the lance, two reelers 5A for each one of Beer Day 2, Elon Data 3, Zorag 4 and Size 6
It is common to have 5B in parallel.

The above reels 5A and 5B need to ensure a stable rolling condition as final finishing rolling machines in a seamless steel pipe manufacturing line using the plug mill method, and the pass line of the raw pipe must be positioned at the minimum interval defined by the center axes of the two rolls. While the raw pipe is supported at three points by two rolls and a nut, the raw pipe is polished by the plug and the two rolls, and the raw pipe is held between the two rolls. This prevents the top and bottom from touching and buckling the thin-walled pipe.

That is, the reels 5A and 5B polish the raw tube that has been elongated and rolled in the plug mill 4, erase the inner surface lines generated in the plug mill 4, smooth the inner and outer surfaces of the tube, and perform slight thinning and expansion. This makes it possible.

However, the tube shape after rolling by the reels 5A and 5B is due to roll wear of the reels 5A and 5B.

It changes with shoe wear, and it is not possible to obtain a predetermined tube shape with high precision only by initial setting of reeler rolling conditions. In particular, when two reels 5A and 5B are arranged in parallel on a rolling line, the rolling accuracy between the two reels 5A and 5B varies, which is not appropriate.

The present invention controls the tube shape after reeler rolling with high precision,
It is an object of the present invention to provide a method for controlling the shape of a tube using a reeler, which can improve product dimensional accuracy and yield.

In order to achieve the above object, the present invention biases the pass line of the raw pipe with respect to the minimum roll interval defined by the center axis of two rolls, and supports the raw pipe at three points by two rolls and a shoe. Under the condition that the tube is plugged and
In a pipe shape control method using a reeler that performs polishing and rolling with several rolls, the torque difference between the two roll drive motors can be adjusted by relatively adjusting the fields of the roll drive motors that drive each roll. , the expansion rate of the raw pipe is controlled.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a plan view showing the rolling state of the reel to which the present invention is applied, and FIG. 3 is a front view of the second factor.

In the reeler, right roll 11 and left roll 12
The plug 13 has a cylindrical shape, the roll axis is arranged obliquely with respect to the horizontal, and the plug 13 has a long cylindrical shape. The raw pipe 14 that has been elongated and rolled by the plug mill in the previous step is
The tube is polished into a spiral shape between the right roll 11 and left roll 12 and the plug 13, and the inner and outer surfaces of the tube are finished smooth and the wall thickness is determined by the gap between the right roll 11 and left roll 12 and the plug 13. 1, the tube is thinned, and further expanded under pressure contact with the lower shoe 15. In addition, the right roll 11 and the left roll 12.

Roll drive motors 11A each consisting of a DC motor
, 12Af7C.

Here, the pass line PL of the blank pipe 14 is biased downward by, for example, about 6 degrees with respect to the minimum roll interval region E defined by the central axes of the right roll 11 and left roll 12. Therefore, the raw tube 14 has a right roll 11 and a left eye roll 12.
In addition, it is possible to polish the pipe under three-point support by the lower shoe 15.

Note that 16 is an upper shoe.

Therefore, in the above embodiment, by relatively adjusting the fields of the roll drive motors 11A and 12A, the torque difference between them can be adjusted, and the expansion rate of the blank pipe 14 can be controlled. Here, the tube expansion rate is the standard outer diameter Do of the raw pipe after reeler rolling under a state where the roll drive motors 11A and 12A are at the standard torque ratio, and the raw material pipe after reeler rolling under an arbitrary torque ratio state. Defined as the ratio of the outside diameter of the tube. Moreover, the control of the tube expansion rate described above also enables control of the elongation rate of the tube 14 by the reeler based on the law of constant volume of the tube 14. Here, the elongation ratio is calculated after reeler-rolling under an arbitrary torque ratio with respect to the standard length LO of the raw pipe after reeler-rolling when the roll drive motors 11A and 12A are at the standard torque ratio. Defined as the ratio of the length of the raw pipe, the right roll 11 and pressure roll 12 to the plug 1
Even if the gap between the base pipe 14 and the base pipe 14 is constant and the thinning given to the base pipe 14 is constant, the torque of the right roll drive motor 11A of the base 1 that sends the base 914 toward the lower part ~ -15,
One motor 11A, 12A for each roll drive is set so that the torque is larger than that of the other left roll drive motor 12A.
When the field is adjusted relatively, the raw tube 14 becomes ■ shoe 15
The tube is strongly pressed against the tube, the expansion rate becomes small and the stretching rate becomes large. Therefore, in this case, the outer diameter of the raw pipe 14 after reeler rolling is relatively small compared to that during standard rolling.
It can be given a relatively large shape or length.

On the other hand, each roll drive motor 11A is configured such that the torque of the right roll drive motor 11A is smaller than the torque of the left roll drive motor 12A.

12A is relatively adjusted, the raw pipe 14 is weakly pressed against the lower shoe 15, and the expansion ratio becomes large and the elongation ratio becomes small. Therefore, in this case, the raw material after reel-rolling The tube 14 is given a shape with a relatively large outer diameter and a relatively small length compared to the time of standard rolling.

Here, for example, in order to make the torque of the right roll drive motor 11A more uniform, the right roll drive motor 11
It is necessary to perform field adjustment to reduce the magnetic flux of A, and it is necessary to reduce the field current of the right roll drive motor 11A or increase its field resistance.

Next, the operation of the above embodiment will be explained.

By adjusting the field of each roll drive motor 11A, 12A, the torque difference between the right roll drive motor 11A and the left roll drive motor 12A is adjusted, and for example, as shown on the horizontal axis in FIG. Ratio TI/T2 of torque T1 of 11A and torque T2 of left roll drive motor 12A
When , the expansion ratio D/D of the raw pipe 14 changes. and the stretching ratio "/Lo" change as shown on the vertical axis in FIG.

It becomes possible to control the length. In addition, in this FIG. 4, the outer diameter and length of the raw pipe 14 after being rolled under the condition where the torque ratio TH,= 0.6 is the reference outer diameter. , the reference length is Lo.

According to the above embodiment, it is possible to control the tube shape after reel rolling with high precision, and it is possible to improve product dimensional accuracy and yield.

In particular, even when two reelers are installed on a rolling line, by applying the present invention to both reelers,
The shape of the product rolled by both reels can be made uniform with each other.

As described above, the present invention biases the pass line of the raw pipe with respect to the minimum roll interval determined by the 1-axis of two rolls, and the raw pipe is rolled three times by two rolls and a shoe.
In a pipe shape control method using a reeler in which the raw pipe is polished and pressed by a plug and two rolls in a point-supported state F, the field of the roll drive motor that drives each roll is adjusted relatively. By doing so, the torque difference between the motors for driving both rolls is adjusted and the expansion rate of the raw tube is controlled.The shape of the tube after reeling is controlled with high precision, improving product size control and yield. It becomes possible to do so.

[Brief explanation of drawings]

Figure 1 is a process diagram showing the general seamless steel pipe manufacturing process, Figure 2
The figure is a plan view showing the rolling state of the reeler to which the present invention is applied, FIG. 3 is a front view of FIG. 2, and FIG. 4 is a diagram showing the control state of the tube shape according to the present invention. 11... Right roll, 11A... Right roll drive motor. 12゛...Left roll, 12A"...Left roll drive motor, 13...Plug, 14...Main pipe, 15°...Lower shoe. Agent: Patent attorney Osamu Shiokawa

Claims (1)

[Claims] (1) The pass line of the raw pipe is biased to the minimum roll interval defined by the center axis of the two rolls, and the raw pipe is
In a tube shape control method using a reeler, in which the blank tube is polished and rolled by a plug and two rolls while supported at three points by three rolls and shoes, the roll drive motors that drive each roll are moved relative to each other. A tube shape control method using a roller that adjusts the torque difference between the roll drive motors and controls the expansion rate of the raw tube by manually adjusting the field.