JPS58103902A - Working method for tubular body - Google Patents

Abstract

PURPOSE:To form increased metal parts of good quality in a part of a tubular body with high productivity by rolling a hollow blank material while changing the rolling gaps between the plural rolling rolls which are obliquely disposed at equal intervals in the circumferential direction around the axis of said material and the mandrel bar inserted into the hollow blank material. CONSTITUTION:A hollow blank material 17 is fed to an upsetting device 20 constituted of 2-3 pieces of rolling rolls 21 disposed at equal intervals on the same circumference and a mandrel bar 22 in a hot state. The device 20 changes the rolling gap assumed by the rolls 21 and the bar 22 during rolling by adjusting the gaps of the rolls 21 disposed with inclination to the axis of the material 17, thus forming increased metal parts in a part of the material 17 in its longitudinal direction. More specifically, the device 20 rolls the material 17 longitudinally from its one end part and forms a bulging increased metal part 17A on the outside surface thereof in the working stages A-D of the figure. The respective stages A-D are repeated over the entire length of the material 17, whereby plural increased metal parts 17A are formed in the material 17 in one-pass rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for processing a tubular body, and particularly to a method for processing a tubular body suitable for upsetting a thickened portion at the end of the tubular body.

In general, as a method for connecting long pipe bodies such as oil country tubular goods, a method is used in which the pipe bodies are successively connected by interposing a joint force at the nine threaded joints formed on the outer and/or inner surface of the pipe ends. ing. For pipes to which the above connection method is applied,
In order to ensure the strength of the threaded portion formed at the end, it is necessary to form a thickened portion at the end.

FIGS. 1 to 3 are explanatory diagrams showing a conventional method for processing a tubular body. In other words, Figure 1 (Figure 1) is
Machining process to form a thickened part 2At outward at the end of the hollow material 1@
FIG. The end of the hollow material 1 heated to a high temperature by an induction heating method or the like is charged into a split die 3A having an inner diameter larger than its outer diameter, as shown in Figure 1 (2), @. At the same time, it has an outer diameter that is approximately the same as its inner diameter. Figure 1 (Q
, Q), the upsetting part 5 of the mandrel bar 4A
The end is upset by A, as shown in Figure 1■.

As shown in (2), it is possible to form the thickened portion 2A. Moreover, FIG. 2 is an explanatory view showing the processing step of forming the thickened part 2B on the inner surface of the end of the hollow material 1. The second drawing, Qll
), the end portion is upset by the upsetting portion 5B of the mandrel bar 41%, so that the thickened portion 2B can be formed. Moreover, FIG. 3 is an explanatory view showing the processing step of forming thickening 112G on the inner and outer surfaces of the end portion of the hollow material 1. As shown in FIG. Fig. 3 1), ■
After being upset by the upsetting part 5C of the mandrel bar 4C as shown in FIG. At the bottom, the end of the mandrel bar 4D is further upset by the upsetting part 50, so that a thickened part 2C can be formed as shown in FIG. 3 [F].

However, the above-mentioned conventional pipe processing methods are particularly difficult for upset processing of difficult-to-process materials such as stainless steel pipes, thick wall upset processing with a large wall thickness increase rate, and elongated pipes with long thickened parts. In upset processing, etc., the pipe wall of the hollow material is likely to buckle during upsetting, scale during heating is likely to be rolled into the pipe, and a heat-affected zone remains due to local heating at the end of the material, resulting in quality problems. , it is accompanied by great difficulties in improving productivity. In addition, in the conventional processing method described above, the material that enters between the split dies becomes fins or fins as shown in Figures 1 to 3 above, so it is difficult to prevent the material from entering between the split dies when re-upsetting or screwing. In this case, it becomes necessary to remove the bulk 6, which significantly reduces the productivity of the tube body.

The present invention was made in view of the above-mentioned conventional facts;
It is an object of the present invention to provide a method for processing a tube body that can form a high-quality thickened part in a part of the tube body with high productivity.

In order to achieve the above object, the present invention provides a mandrel bar inserted by a plurality of rolling rolls that are equally distributed in the circumferential direction around the axis of the hollow material and arranged at an angle with respect to the axis of the hollow material. In a tubular processing method in which a hollow material is rolled while advancing in a spiral shape, the piezoelectric gap II between the Raku rolling roll and the mandrel bar is changed during rolling to form a thickened part in a part of the longitudinal direction of the tubular body. It was designed to do so.

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

FIG. 4 is a manufacturing process diagram showing the first embodiment of the present invention connected to two stages of pipe production using the Mannesmann-mandrel mill system, and the wLS diagram is a side view showing the main part of the first embodiment cut away. Figure 6 is a plan view of the main part of Figure 5, and Figure 7 is a plan view of the main part of Figure 5.
Figures (4) to (■) are large-scale cross-sectional views of main parts 1 showing different machining conditions of the first dormitory example.As shown in Figure Z4, round steel 11
is heated to a predetermined temperature in a heating furnace 12, pierced with a piercer 13, rolled to reduce its outer diameter and thinner at the same time in a mandrel mill 14, reheated to a predetermined temperature in a reheating furnace 15, and pierced by a reducer 16. The hollow material 17 is formed by being squeezed and compressed to a predetermined outer diameter and wall thickness. This hollow material 17 is transferred under hot conditions to an upset processing device 2G to which the present invention is applied. Here, the outer diameter and wall thickness of the hollow material 17 do not need to be extended to the outer diameter and wall thickness corresponding to the middle part of the pipe body after upsetting, and the outer diameter and wall thickness of the hollow material 17 do not need to be extended to the outer diameter and wall thickness corresponding to the middle part of the pipe body after upsetting. It is an intermediate dimension that is slightly larger than the dimensions corresponding to the diameter and wall thickness.

As shown in FIG. 5 and FIG.
It is composed of a rolling roll 21 and a mandrel bar 22. The rolling roll 21 has a substantially conical shape and is arranged at an inclination angle of 0 with respect to the axis of the hollow material 17, and
The opening degree of the roll, the above-mentioned inclination angle θ, and the roll rotation speed can be adjusted. That is, the rolling roll 21
is a hollow material 1T into which a mandrel bar 22 is inserted.
The hollow material 17 can be rolled while being moved forward in a spiral manner.

Here, the upset processing device 20 changes the relationship between the roll roll 21 and the mandrel bar 22 during rolling by adjusting the roll opening degree of the roll roll 21, and changes the longitudinal direction of the rolled material. It is possible to form a thickened part in a part. That is, the upset processing device 20
7t - Rolling in the longitudinal direction from one end, following (2) to Q)
The thickened part 17A bulges on the outer surface due to the processing step 3.
This makes it possible to perform upset processing to form a (4) First, attach the mandrel bar 2 to the inner diameter part of the hollow material 17.
2 is inserted, and the roll opening of the roll 21 is fixed at a relatively large opening corresponding to the outer diameter of the thickened portion 17A formed in the hollow material 17.
1, the mandrel bar 22, and the o rolling gap set approximately equal to the thickness of the thickened portion i7A, the hollow material 17 is rolled into the seventh
As shown in FIG. 4, the thickened portion 17At- is formed by rolling. ) Next, when the thickened portion 17A reaches a predetermined length, the roll opening of the rolling roll 21 is narrowed at a speed commensurate with one degree of rolling, as shown in FIG. 7 (6). The outer diameter of the hollow material 1T is reduced at a predetermined taper angle. Next, when the outer diameter of the hollow material 17 on the exit side of the rolling roll 21 reaches the preset outer diameter of the tubular intermediate portion 17ElO, by fixing the roll opening degree of the rolling roll 21, The rolling gap between the rolling roll 21 and the mandrel bar 22 is set to be approximately equal to the thickness of the intermediate portion 17B, and the intermediate portion 17B is rolled as shown in FIG. 70. 0th order, middle part 1
7B reaches a predetermined length, one roll of the rolling roll 21 is opened at a speed commensurate with the rolling speed, and the outer diameter of the hollow material 17 is adjusted at a predetermined taper angle as shown in FIG. Expand the diameter. Hollow material 1T at the exit of rolling roll 21
When the outer diameter of the thickened portion 17A reaches the outer diameter of the thickened portion 17A, the roll opening of the rolling roll 21 is fixed, and the rolling roll 21 fixed at the roll opening and the mandrel bar 22 are used to create a new thickening. Part 17A is rolled. As described above, each of the above steps (4) to
By repeating this process, a plurality of thickened portions 17A are formed in the hollow material 17 in one pass of rolling.

Therefore, the hollow material 17 can be made by cutting the central part of the thickened part 17A formed in the middle in the longitudinal direction.
This results in a plurality of tube bodies having thickened portions 17A at both ends. In addition,
In the above process error 0, the rolling roll 21 is the hollow material 1!
] If the inclination angle θ made with respect to the axis is made small, the forward distance of one rotation of the medium #AIT is reduced, and the surface quality of the 6L'5 taper portion is improved.

Figure @8 is a side view showing a sectioned main part of the 2'5-embodiment according to the present invention. In this J2 embodiment, the rolling rolls 211 are capable of forming thickening ISI7:s- which bulges on the inner surface of the tube body, and the roll spacing is approximately -t.
C, the mandrel bar 23 is moved at a constant speed b1, and the large diameter 1 of the mandrel bar 23 is moved between the rolling rolls 21.
The amount of rolling between the pressure mill 21 and the mandrel bar 23 can be changed by passing through the s23A, the f-shaped roof 23B, and the small diameter portion 23C in sequence. That is, the small diameter part 23G of the mandrel bar 23 and the rolling roll 21 form a thickened part 1ycv by the trap, and the mandrel bar
A relatively thin intermediate portion 17B is formed by the large diameter portion 23A of the roller 23 and the rolling roll 21, and by controlling the moving speed of the tapered portion 23El of the mandrel bar 23, the rolling amount lli between the rolling roll 21 and the tapered portion 23B is By changing the thickness, a teno (portion) connecting the thickened portion 17C and the intermediate portion 17B is formed.

In this second embodiment, although the roll interval of the rolling rolls 21 is kept substantially constant in principle, it may be corrected as necessary by the amount of tube expansion due to wall thickness reduction.

FIG. 9 is a side view showing a main part of the third embodiment according to the present invention in a broken state. In this third embodiment, the roll opening degree of the rolling roll 21 is adjustable, and the mandrel bar 23 is moved relative to the rolling roll 21, and the large diameter portion 23A of the mandrel bar 23 is moved between the rolling rolls 21. , the tapered portion 23B and the small diameter portion 23G in order. Therefore, the rolling gap between the rolling roll 21 and the 1-drel bar 23 changes by adjusting the roll opening degree, and also changes by the movement of the mantle full bar (-23), thus forming a thickened part 17E that bulges on the inner and outer surfaces of the tube body. be done.

According to the second to third embodiments described above, thickened portions of a predetermined length are formed at predetermined intervals in the longitudinal direction of the hollow material 17 by one pass rolling, and therefore, thickened portions are formed at predetermined lengths at predetermined intervals in the longitudinal direction. By cutting the thickened portion at the center, a plurality of tube bodies having thickened portions at both ends can be obtained.

Also, adjustment of the roll opening degree of the rolling roll 21 and/or large diameter portion 23A7 of the mandrel bar 23:・small diameter portion 23
By moving C with respect to the rolling roll 21 in one section, it is possible to form a thickened part of the desired thickness in the hollow material, and therefore it is possible to perform large-scale upsetting machining that conventionally required upsetting several times. It is also possible to easily carry out rolling in one pass. In addition, the taper portion 23 of the mandrel bar 23
By adjusting the shape of B and its moving speed,
It becomes possible to control the shape of the tapered portion inside the tube to a predetermined shape. Furthermore, since the thickened portion is formed by the compression of the rolling roll 21 and the mandrel bars 22 and 23, it is possible to easily upset-process materials that are difficult to process, such as stainless steel pots. Furthermore, by forming thickened portions on the rolling roll 21 and the mandrel bar 22°, it becomes possible to easily carry out upset processing of a long length. In addition, the hollow material 17u rolling roll 21 and the mandrel bar 2
Since the thickened portion is formed by spiral rolling at 2.degree.

The rolling mill constituting each of the above embodiments is an Arasel mill type,
A rolling mill such as a rotary sizer type or a three-roll planetary mill type is applicable.

Further, the hollow material used in each of the above embodiments is not limited to a material rolled by a reducer rolling mill based on the Mannesmann-mandrel mill method, but also a material punched by a Mannesmann drilling machine.

It can be widely applied to materials that are perforated and stretched using the press method. In addition, the hollow material used in the present invention is
The material is not limited to hot material used in the pipe making process, but may also be used by reheating cold material.

As described above, the present invention enables a hollow material into which a mandrel bar is inserted by a plurality of rolling rolls that are equally distributed in the circumferential direction around the axis of the hollow material and arranged at an angle to the axis of the hollow material. In a method of processing a tubular body in which it is rolled while moving forward in a spiral, each rolling roll and mandrel bar are
By changing the rolling gap during rolling, a thickened part is formed in a part of the tube in the longitudinal direction, so a high quality thickened part can be formed in a part of the tube with high productivity. It has the effect of being able to

[Brief explanation of the drawing]

@1 Figures (4) to 1 are cross-sectional views showing the method of processing a tube according to the conventional example, and Figure 1 (8) is IB-■ in Figure 1 (f).
Cross-sectional view along BH, Figure 1 0 is ID-ID# of Figure 1 0
The cross-sectional view along @1 Figure F) is IF-IFii in Figure 1 ■.
[Cross-sectional views along Figure 2 (A) to 0 are cross-sectional views showing another conventional method for processing a tube, and Figure 2 (6) is
A cross-sectional view taken along line IIB-11B in Figure (G), Figure 2 0 is a cross-sectional view taken along line 2111-nova, Figure 3
F) Fi is a cross-sectional view showing a method of processing a tube body according to another conventional example, and FIG. 3 (6) is a cross-sectional view taken along the line IB-IB in FIG. 3 (4), and FIG. 3 (2) Figure 3 is a cross-sectional view along the 00ID-Rin line, Figure WJ4 is a manufacturing process diagram showing the first embodiment of the present invention connected to the pipe manufacturing process, and Figure 5 is a cutaway of the main part of the first embodiment. 6 is a plan view of the main part of FIG. 5, WI7 (2) to 0 are enlarged sectional views of the main part showing different processing states of the first embodiment, and FIG. FIG. 9 is a side view showing a broken part of the main part of the second embodiment of the present invention, and FIG.
FIG. 2 is a cross-sectional view showing main parts of the embodiment. 17...Hollow material, 17A, 17G, 17E...Thickened part, 21...
Rolling roll, 22.23... Mandrel bar 1 23A °°゛large diameter part, 23B... Taper part, 2
3C...Small diameter part. Agent Patent Attorney Osamu Shiokawa Figure 1 Figure 2

Claims (1)

[Claims] (1) While the hollow material into which the mandrel bar is inserted is advanced in a spiral manner by a plurality of rolling rolls that are equally distributed in the local direction around the axis of the hollow material and arranged at an angle to the axis of the hollow material. A method for processing a tubular body to be rolled, characterized in that the rolling gap between each rolling roll and a mandrel bar is changed during rolling to form a thickened part in a part of the longitudinal direction of the tubular body. Method.