JPH07246403A - Method for reducing metallic tube and device therefor - Google Patents

Abstract

PURPOSE:To change the outside diameter of tube into an arbitrary size in a manufacturing line without generating the torsion and bend on the metallic tube. CONSTITUTION:Planetary type stretch reducers 3a, 3b, 3c in which plural rolling rollers 2 are arranged in a concentric circular shape on the outer surface of the metallic tube l and with which reduction is added to the outside diameter while revolving the groups of the rollers 2 around the tube axis are used and these reducers are arranged in a tandem shape. By making the angle of inclination of the rolling roller 2 to the tube axis in each reducer alternately in the reverse direction and also alternately reversing the rotational direction of the group of the rollers 2 in each reducer, reduction is applied to the metallic tube 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for drawing an outer diameter of a metal tube, and more particularly to a method and apparatus for drawing a welded steel tube, a welded stainless tube or the like by cold drawing.

[0002]

2. Description of the Related Art As a method for producing a long metal tube, there are various methods such as a mandrel mill method for a seamless tube, a high frequency welding method for a welded tube, an arc welding method, a laser welding method and a forging method. The tubes produced by these methods are
It is then finished to a specified outer diameter with a sizer or stretch reducer.

Further, Japanese Patent Laid-Open No. 2-41706 discloses that
The outer diameter of the metal tube is reduced by pressing the rolling rollers arranged concentrically on the outer surface of the metal tube at an appropriate inclination angle to the tube axis and rotating the metal tube at high speed. A drawing method is disclosed.

[0004]

In the conventional sizer or stretch reducer, since it is necessary to use a dedicated caliber roll according to the finishing dimension, it is impossible to finish the outer diameter to an arbitrary dimension. If a tube with an arbitrary outer diameter is to be obtained, an infinite number of finishing rolls must be prepared, which is unrealistic in terms of work and manufacturing costs.

Further, in the method disclosed in Japanese Patent Laid-Open No. 2-41706, it is possible to finish to an arbitrary outer diameter, but in the case of a thin-walled pipe, the pipe easily buckles during processing,
In the case of thick-walled pipes, the mill strength is likely to be restricted, and in each case, there is a certain limit in the amount of reduction. Further, there is a drawback that the pipe is apt to be twisted or bent by processing.

The present invention has been made in view of the above circumstances, and it is a throttle for a metal tube capable of changing the outer diameter of the metal tube to an arbitrary size in a production line without causing twisting or bending of the metal tube. An object of the present invention is to provide a processing method and device.

[0007]

In order to solve the above-mentioned problems, the present invention has a plurality of rolling rollers arranged concentrically on the outer surface of a metal tube and rotating the group of rollers around the tube axis. On the premise of a drawing method of a metal tube using a planetary type drawing and rolling machine that applies rolling to the outside diameter of the tube, firstly, a plurality of the rolling machines are arranged in a tandem shape in the tube axis direction, and further, The inclination angle of the rolling roller with respect to the tube axis in each rolling mill is alternately set in the opposite direction in each rolling mill,
A method for drawing a metal tube, characterized in that the rolling directions of the roller groups are alternately reversed in each rolling mill. Second, a plurality of the rolling mills are arranged in a tandem shape in the axial direction of the rolling mill, and each rolling mill is arranged. Characterized in that an axial tension is applied to the pipe by increasing the inclination angle of the rolling roller with respect to the pipe axis in the latter rolling mill or increasing the planetary rotation speed of the rolling roller in the latter rolling mill. Thirdly, a method for drawing a metal tube Thirdly, a plurality of the rolling mills are arranged in a tandem shape in the pipe axis direction, and a rolling reduction in a rolling mill at a final stage among the plurality of rolling mills is performed as a light rolling reduction, Disclosed is a method for drawing a metal pipe, which comprises controlling the bending of the pipe by displacing a roller group of a rolling mill of a multi-stage rolling mill at an arbitrary position in a direction perpendicular to the pipe axis.

Fourthly, a plurality of rolling rollers are concentrically arranged on the outer surface of the metal tube, and the planetary group applies a reduction to the outer diameter of the tube while rotating the group of rollers around the tube axis. A drawing apparatus for metal pipes provided with a rolling mill, wherein a plurality of the rolling mills are arranged in a tandem shape in the axial direction of the pipe so that the outer diameter of the pipes can be continuously reduced. Provided is an apparatus for drawing a metal tube, wherein an inclination angle and a rotation direction of a roller with respect to a tube axis can be arbitrarily set, and a rolling roller position of a rolling mill at a final stage can be changed with respect to the tube axis. It is a thing.

[0009]

In the present invention, a plurality of planetary-type drawing and rolling mills are used, and these are arranged in a tandem to draw a metal pipe. Therefore, both the thin-walled pipe and the thick-walled pipe are reduced in outer diameter (a reduction amount). ) Can be increased.

In the first aspect, the buckling limit of the thin-walled pipe is significantly improved by alternately setting the inclination angles of the rolling rollers of the tandemly arranged rolling mills in the opposite directions. The twisting of the tube can be prevented by alternately reversing the rotation direction of the tube.

Further, in the second aspect, the inclination angle of the roller is gradually increased toward the rear side (downstream side) of the rolling mill arranged in tandem, or the roller is inclined toward the rear side of the rolling mill. By gradually increasing the planetary rotation speed of, the tensile stress can be generated in the metal pipe, and the buckling limit of the thin-walled pipe can be improved by giving an outer diameter reduction under this tensile stress. .

Further, in the third embodiment, the rolling for rolling in the last rolling mill among the rolling mills arranged in tandem is made extremely light rolling to smooth the pipe surface, and at the same time the center of the roller group is rolled. Is arbitrarily displaced in the vertical direction from the pipe axis (pass line center), it is possible to prevent bending of the pipe caused by unevenness of the pipe material (welding portion) or the like. These actions can be achieved by the processing apparatus having the above configuration.

[0013]

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a configuration example of a drawing apparatus according to the present invention. In this device, the sizer or pinch rolls 4a and 4b are arranged on the upstream side of the metal pipe (base pipe) 1 to be processed, similarly to the conventional welded pipe manufacturing line, and three units are arranged on the downstream side thereof. The planetary-type reduction rolling mills 3a, 3b, 3c are arranged in a tandem shape. These planetary type squeezing rolling mills 3a, 3b, 3c have a plurality of rollers 2 that make a planetary rotation around the shell 1, and these rollers 2 drive a planet rotation mechanism (not shown) provided outside. It is rotated by force.

The base tube 1 and the roller 2 have a positional relationship as shown in FIGS. That is, the roller 2
Has an inclination angle of θ with respect to the tube axis. Such a roller 2 is arranged around the tube, and the component force Fb from these rollers 2 sends the tube 1 downstream in the tube axis direction. Be done. Such a basic operation is the same as that of the conventional device shown in FIGS. 4 and 5.

What is characteristic of such a device according to the present invention is that the inclination angle of the roller 2 can be arbitrarily set, the rotation direction can be arbitrarily set, and the rolling mill at the final stage ( In the figure, the position of the roller 2 of the rolling mill 3c) can be changed with respect to the pipe axis.

As described above, a plurality of planetary-type drawing and rolling machines are drawn by a device arranged in tandem, so that the outer diameter drawing amount (rolling down amount) of both thin-walled pipes and thick-walled pipes is reduced.
Can be increased.

Further, in the first aspect, the inclination angle of the rolling roller 2 with respect to the tube axis in each rolling mill is alternately set in the opposite direction, and the rotation direction of the rollers is alternately set in each rolling mill. Rotate. For this reason, the buckling limit of the thin-walled pipe is significantly improved, and the twisting of the pipe can be prevented.

Further, in the second aspect, the inclination angle of the roller is gradually increased or the planetary rotation speed of the roller is gradually increased toward the rear side of the plurality of rolling mills. As a result, a tensile stress can be generated in the raw pipe, and the buckling limit of the thin-walled pipe is improved by giving an outer diameter reduction under this tensile stress.

Further, in the third mode, the reduction in the rolling mill at the final stage is made light reduction, and the roller group of the rolling mill at the final stage (in the figure, rolling mill 3c) is placed at an arbitrary position in the direction perpendicular to the pipe axis. Displace. As a result, the surface of the pipe becomes smooth, and bending of the pipe caused by unevenness of the pipe material such as a welded portion is prevented.

Next, the result of a test in which the outer diameter drawing process is applied to the electric resistance welded steel pipe using the apparatus having the above-mentioned configuration will be described. For comparison, a test using a conventional device was also performed. Table 1 shows the test conditions.

[0021]

[Table 1]

(Embodiment 1) In this embodiment, FIG.
Using the above apparatus, drawing processing was performed under the conditions shown in Table 1 with 2 stands (2 passes) and 3 stands (3 passes). In this case, the roller inclination angle and the roller rotation direction of the second stand (rolling machine 3b in FIG. 1) were opposite to those of the first stand (rolling machine 3a in FIG. 1). In addition, 1 of the conventional method
In the case of the stand (1 pass), drawing processing was performed under the same conditions.

At that time, a thin pipe (ratio of wall thickness t to outer diameter D t /
The buckling limit under the outer diameter pressure of D = 3.0% to 5.1%) is shown in FIG. As is clear from this figure, in the case of the method of the present invention in which the drawing process is performed with 2 stands (2 passes) and 3 stands (3 passes), compared with the case of the conventional 1 stand (1 pass), It was confirmed that the bending limit was significantly improved. It was also confirmed that the buckling limit of the 3rd pass was higher than that of the 2nd pass.

In this embodiment, No. The roller tilt angle and the roller rotation direction of the two stands (two passes) were reversed, but when the tilt angle and the rotation direction were the same for all three stands, the buckling limit did not improve so much. Further, when the roller inclination angles and the rotation directions of the 1-stand and the 2-stand are reversed, as shown in FIG. 7, the twist of the pipe generated in the 1-stand is returned by the 2-stand, and the twist can be almost eliminated. confirmed.

(Embodiment 2) Using the apparatus shown in FIG. 1, the roller inclination angle is set to 10 ° for one stand and 12 ° for two stands.
Was set, and drawing was performed according to the conditions in Table 1. The buckling limit in that case is shown in FIG.

As shown in FIG. 8, the buckling limit is increased as compared with the case of one pass by increasing the inclination angle of the roller of the rear stand to increase the velocity vector in the pipe axis direction and generating tensile stress in the pipe body. Was confirmed to improve. It is obvious that the effect of increasing the velocity deviation in the tube axis direction of the rear stand in this way can also be obtained when the roller rotation speed of the rear stand is increased.

(Embodiment 3) In this embodiment, under the conditions shown in Table 1, the last stage stand (rolling machine 3c in FIG. 1) in the apparatus of FIG. Then, it was drawn. The result is shown in FIG. 9 in comparison with the case of one pass.

As shown in FIG. 9, when the outer diameter is reduced by one stand, the pipe is apt to bend due to non-uniformity of the material of the welded portion, but a plurality of stands are used, and the last stand is used. It was confirmed that the bending of the pipe can be prevented by controlling the position of the roller in the vertical plane under a light pressure. Further, the surface roughness is also improved by reducing the pressure of the last stand to 1% or less. In addition,
Regarding only the surface roughness, it was confirmed that reducing the roller inclination angle is also effective.

(Embodiment 4) In this embodiment, the outer diameter drawing of thin-wall ERW steel pipes was compared between the conventional method and the method of the present invention. The results are shown in Table 2.

[0030]

[Table 2]

As is clear from Table 2, by applying a plurality of stands arranged in tandem and changing the direction and angle of the roller inclination, the working limit is greatly expanded, and the direction of the roller inclination is changed. It was confirmed that a slight reduction in pressure on the final stand also had a significant improvement effect on the surface condition.

[0032]

As described above, according to the present invention, a plurality of planetary type outer diameter rolling mills are installed in a metal pipe manufacturing line, and the rolling direction and the rotating direction of the rolling rollers, the tilt angle, or the final rolling mill are installed. By appropriately adjusting the reduction amount and roller position of the rolling mill of the multi-stage rolling, it is possible to efficiently produce a pipe of an arbitrary outer diameter from a mother pipe of the same size with high dimensional accuracy without twisting or bending of the metal pipe. It becomes possible.

Therefore, it is economically extremely effective in that it has the effects of reducing frequent roll replacement, reducing the number of rolls held, improving work efficiency, and freely manufacturing small-lot products of arbitrary size. .

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration example of a drawing apparatus according to the present invention.

FIG. 2 is a side view showing a state of rollers of a planetary type squeezing mill in the apparatus shown in FIG.

FIG. 3 is a front view showing a state of rollers of a planetary-type drawing and rolling mill in the apparatus of FIG.

FIG. 4 is a side view showing a conventional drawing device.

FIG. 5 is a front view showing a conventional drawing device.

FIG. 6 is a graph showing the buckling limit of the shell in Example 1.

FIG. 7 is a graph showing the twist of the shell in Example 1.

FIG. 8 is a graph showing the buckling limit of the shell in Example 2.

FIG. 9 is a graph showing a bent state of a raw tube in Example 3.

[Explanation of symbols]

1 ... Metal tube (base tube), 2 ... Roller, 3a, 3b,
3c ... rolling mill (stand), 4a, 4b ... sizer (or pinch roll), θ ... roller inclination angle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yonesho Fujita Marunouchi 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK (72) Inventor Manabu Kiuchi 2-12-21 Shinjuku, Zushi, Kanagawa

Claims (4)

[Claims] 1. A planetary-type squeezing and rolling machine, in which a plurality of rolling rollers are concentrically arranged on the outer surface of a metal tube and the roller group is rotated around the tube axis to reduce the outer diameter of the tube. A method of drawing a metal tube used, wherein a plurality of the rolling mills are arranged in a tandem shape in the pipe axis direction, and the inclination angle of the rolling roller in each rolling mill with respect to the pipe axis is alternately reversed in each rolling mill. Direction, and the rolling direction of the roller group is alternately reversed in each rolling mill. 2. A planetary-type squeezing and rolling machine in which a plurality of rolling rollers are concentrically arranged on the outer surface of a metal tube and the roller group is rotated around the tube axis to reduce the outer diameter of the tube. A method of drawing a metal tube used, wherein a plurality of the rolling mills are arranged in a tandem shape in the pipe axis direction, and the inclination angle of the rolling roller in each rolling mill with respect to the pipe axis is made larger in the subsequent rolling mill. Alternatively, a method for drawing a metal tube is characterized in that axial tension is applied to the tube by increasing the planetary rotation speed of the rolling roller in the subsequent rolling mill. 3. A planetary-type squeezing and rolling machine, in which a plurality of rolling rollers are concentrically arranged on the outer surface of a metal tube, and the roller group is rotated around the tube axis to reduce the outer diameter of the tube. A method of drawing a metal tube used, wherein a plurality of the rolling mills are arranged in a tandem shape in the pipe axial direction, and a reduction in a rolling mill at the last stage among the plurality of rolling mills is a light reduction, and A method for drawing a metal pipe, wherein bending of the pipe is controlled by displacing a roller group of a rolling mill at the final stage to an arbitrary position in a direction perpendicular to the pipe axis. 4. A planetary-type squeezing and rolling machine in which a plurality of rolling rollers are concentrically arranged on the outer surface of a metal tube, and the roller group is rotated about the tube axis to reduce the outer diameter of the tube. A drawing apparatus for metal pipes, comprising a plurality of rolling mills arranged in a tandem shape in the axial direction of the rolling mill so that the outer diameter of the rolling mill can be continuously reduced, and A metal pipe drawing apparatus characterized in that an inclination angle and a rotation direction with respect to can be arbitrarily set, and a rolling roller position of a rolling mill at a final stage can be changed with respect to a pipe axis.