JPH02117706A - Method for reeling seamless steel tube - Google Patents

Abstract

PURPOSE:To concurrently attain improvement of both biting property of rolls and reeling effect and tube quality by bringing a toe-in angle of the roller axis of reel rollers to be large in biting a tube and to be small after biting. CONSTITUTION:Reel rollers 21, 22 are crossed, tilted to each other and are rotated. When a tube is bitten, the rollers 21, 22 move in the direction shown by the arrow to bring a plug 3 to be inserted, and perform reeling. The rollers 21, 22 are supported by yokes 31, 32 and yokes 41, 42 at the biting and outlet sides, respectively. The rollers 21, 22 are made to toe-in by a required angle by use of screws 51, 52 and 61, 62. A tube detector 10 detects biting start of a tube, input a signal to a controller 11 to make both a toe-in angle and a biting force large. At direction of biting completion, the detector 10 make a toe-in angle small to reduce flaw generation percentage on the tube during reeling.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reeling method for polishing the inner and outer surfaces of a pipe in a method of manufacturing a seamless steel pipe using the Mannesmann plug mill method.

[Conventional technology]

To manufacture seamless steel pipes using the Mannesmann plug mill method, a piercer is used to perforate the axial center of a heated billet, the wall is made thinner and the diameter is expanded using an elongator, and after elongation and rolling is performed using a plug mill, the inner and outer surfaces of the pipe are cut using a reeler. This is done by reeling and finishing with sipes to the specified dimensions.

In the reeling step, a reeler roll and a
- A reeler consisting of a rubber plug performs wall thickness rolling at the same time as the diameter of the tube.

FIG. 4 is a schematic plan view showing the main parts of the reeler. Beam between cylindrical reeler rolls 21 and 22 - Love Lug 3
are arranged. In order to perform reeling by applying a frictional force to the tube l held in the rolls 21, 22 and moving the tube l spirally in its length direction, the plug 3 is inserted. It is necessary to rotate the rolls in the same direction at the same speed and to incline the roll axes so as to intersect with each other by a required angle with respect to the horizontal direction.

Slanting the tube in this way is necessary to provide propulsive force to the tube, but on the other hand, this inclination reduces the contact area between the rolls and the tube, so the tube is not rolled smoothly and the tube is not rolled smoothly. The quality of the internal and external surfaces may deteriorate.

In order to solve the above-mentioned problem, in order to bring the distance between the rolls of the two reeler rolls closer together on the tube engagement side, the roll axes of the rolls are set at a required angle (usually 0.4e~0.9@
It is known that if the toe-in adjustment is performed by increasing the toe-in by a certain amount, the contact area between the roll and the tube will increase, and the quality of the tube will improve.

[Problem to be solved by the invention]

When performing the toe-in adjustment, in order to increase the contact area between the roll and the tube, it is better to set the toe-in angle as small as possible within the normal toe-in angle mentioned above, but if this is too small,
When the tube is bitten, a biting failure occurs, resulting in poor reeling efficiency. On the other hand, in order to improve the biting property, it is better for the toe-in angle to be larger than the above-mentioned normal toe-in angle, but if this is exceeded, the contact area between the roll and the tube becomes small, making it impossible to roll smoothly, especially inside the tube. Bottom of the face is likely to occur. In this way, improving the quality of the pipe and improving the biting property are in a mutually contradictory relationship, and it has not been possible to achieve both.

The present invention has been made in view of the above circumstances, and it improves the biting property and reeling efficiency by increasing the toe-in angle when the tube is bitten, and reducing the toe-in angle after the tube is bitten. , the purpose is to provide a seamless steel pipe reeling method that improves the quality of the pipe.

[Means to solve the problem]

The seamless steel pipe reeling method according to the present invention is a seamless steel pipe reeling method in which the roll axis of the reeler roll is towed in at a predetermined angle to the side where the reeler roll bites the pipe, thereby expanding the diameter of the pipe and rolling the wall thickness. In this method, when the tube is biting, the toe-in angle is large, and after biting,
It is characterized by a small toe-in angle.

[Effect]

In the present invention, when the tube is bitten by the reeler roll, the toe-in angle is increased, and the distance between the rolls on the biting side of the tube is reduced. This improves the biting properties and improves the reeling efficiency.

Moreover, after biting, the toe-in angle is made smaller, and the distance between the rolls is made greater than that at the time of biting. This increases the contact surface between the tube and the rolls, resulting in smooth rolling, which improves the quality of the tube.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof.

FIG. 1 is a schematic diagram showing an apparatus for carrying out the method of the present invention. A beam-rubber 3 is arranged between the reeler rolls 21.22, which rolls 21.22 are tilted and rotated in a manner that crosses each other as described above by means of a reeler roll drive (not shown). When the tube is caught in the rolls 21 and 22, the tube moves in the direction of the white arrow 1 in the figure, that is, in the direction of the pass line of the tube, while allowing the plug 3 to penetrate therethrough, and is reeled. The rolls 21.22 are connected to a yoke 31.32 on the bite side of the tube and a yoke 41 on the exit side of the tube.
．． 42, and a series of mechanisms for adjusting the toe-in of the rolls 21 and 22, respectively, on the opposite side to the opposite side of the rolls, that is, the yokes 31.32 and 41.4.
screws 51.52 and 61.62 for moving the roll 21.22 and twisting the roll 21.22 by a required angle, and a screw drive device 71.7 connected to each of these screws.
2 and 81.82 are connected to these drive devices respectively, and the rotation of the screws is intermittent to drive the rolls 21.22.
Clutch 9 for fixing the toe-in angle at a required angle
1 and 92 are arranged. By means of these mechanisms, the roll axes of the rolls 21 and 22 are symmetrically twisted and fixed at a required angle to the tube on the biting side of the tube, as shown by the dotted chain line in the figure.

In addition, a tube detector 10 consisting of an HMD is placed on the side where the tube is caught.
is arranged to detect signals at the time when the tube is bitten and at the end of reeling. The detected signal is input to a control device 11 that controls a series of mechanisms for adjusting the toe-in. Before starting reeling, the control Il device 1
1 is the screw drive device 71.72 and 81.82
and slide the yokes 31.32 and 41.42 using the screws 51.52 and 61.62, respectively, to change the toe-in angle to the normal toe-in angle 1, for example 0.6°.
Set a larger angle θ, = 0.7°, and clutch 9I
and 92 to fix the toe-in angle at 01=0.7°. In this state, the tube is caught between the rolls 21 and 22 and reeling is started. When the pipe detector 10 detects the point at which the pipe is caught and an on-road signal is input to the control device 11, the control device 1 disengages the clutches 91 and 92 and fixes the toe-in angle at θ. screw 5
1.52 and 61.62 are screw drive devices 71.72
and 81.82, the yokes 31.32 and 4
1.42 in the direction toward the tube and the direction away from the tube, respectively, and set the toe-in angle to a toe-in angle θt ``' 0 smaller than the conventional method's toe-in angle = 0.6@
．． Let it be at 5°. When the tow-in angle reaches 02, the clutches 91 and 92 are engaged, and the tow-in angle is fixed at θ2 until the pipe reeling is completed. Further, when the tube detector 10 detects the end of reeling and an off-road signal is input to the control device 11, the control device disengages the clutches 91 and 92 and turns the screw 51 which had fixed the toe-in angle at θ2. .52 and 6L 62 is screw drive device 7
1.72 and 81.82 and slide the yokes 31.32 and 41.42 in the direction away from the tube and in the direction toward the tube, respectively, until the toe-in angle becomes θ1, and when the toe-in angle becomes θ, clutches 91 and 92
and fix the toe-in angle at θ1.

As a result, the rolls 21, 22 are again at the tow-in angle in preparation for biting the tube, and are ready to begin the next gluing-ring operation.

FIG. 2 is a graph showing the control details of the method of the present invention. The vertical axis shows the toe-in angle, and the horizontal axis shows time. The toe-in angle is set to θ=0.7@ in order to emphasize the biting property when biting the tube. Due to the on-load signal when the pipe is caught in the reeling roll (1+ in the figure), the toe-in angle decreases from θ to θz"0.5@, and when the toe-in angle reaches 02 (in the figure) tz)
The toe-in angle is fixed, and reeling operations are performed with emphasis on quality. Furthermore, when reeling ends (
Due to the offload signal (tri) in the figure, the toe-in angle increases from θ2 to θ1, and a state is reached in which it is possible to start the next reeling.

Figure 3 shows API standard c75. A pipe with an outer diameter of 244.5 u, a wall thickness of 11.99 mm, and a length of 12,500 m is to be reeled, the rotation speed of the reeling roll is 12 Orpm, and the toe-in angle is 0.1 from 0.4'' to 0.96. @
It is a graph showing the result of reeling by changing it in increments. The vertical axis is the internal flaw occurrence rate (0) and the biting failure rate (.), and the horizontal axis is the toe-in angle.

The toe-in angle that minimizes the internal flaw occurrence rate at approximately 5% is 0.
．． The toe-in angle is 5°, and the toe-in angle that gives the lowest biting defect rate of about 8% is 0.7'. Further, the internal flaw occurrence rate of the conventional method when the toe-in angle is 0.6° is about 13%, and the biting failure rate is about 22%. As you can see from this result,
The method of the present invention, which increases the toe-in angle at 0.7° at the time of biting and reduces it to 0.5° after the biting is completed, is a reeling operation with a toe-in angle fixed at 0.6° in the conventional method. The internal flaw occurrence rate can be reduced by about 8 points and the biting defect rate by about 14 points, and both the internal flaw occurrence rate and the biting defect rate can be brought to the lowest values.

〔Effect of the invention〕

As detailed above, in the method of the present invention, seamless steel pipes are manufactured by selectively using both the tow-in angle that emphasizes the biting property and the tow-in angle that emphasizes the quality of the pipe depending on the reeling process. Therefore, an excellent effect is achieved in that both operability such as roll biting property and reeling efficiency and the quality of the pipe can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an apparatus for carrying out the method of the present invention, Fig. 2 is a graph showing the control details of the method of the present invention, and Fig. 3 is a diagram showing a case where one ring is performed by changing the toe-in angle. A graph showing each internal flaw occurrence rate and biting failure rate,
FIG. 4 is a schematic plan view showing the main parts of the beam beam. 21, 22... Leeler roll θ... Tow-in angle patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono l Figure 0.4 0.5 0.6 0.7 0.8 0.9 θ[degl Figure 1, 12 Oscillator off-road diagram

Claims (1)

[Scope of Claims] 1. A seamless steel pipe reeling method in which the roll axis of the reeler roll is turned in at a predetermined angle to the side where the reeler roll bites the pipe to expand the diameter of the pipe and roll the wall thickness, comprising: A reeling method for a seamless steel pipe characterized by increasing the toe-in angle when the pipe is biting, and decreasing the toe-in angle after the biting.