JPS60152320A - Manufacture of metallic pipe having thickness difference in longitudinal direction of pipe - Google Patents

Abstract

PURPOSE:To manufacture the titled metallic pipe of a high accuracy at a low cost by making a plate width of a metallic plate material have a sufficient allowance in advance, executing a preliminary forming to a different thickness difference, and forming it to a cylindrical shape by cutting out the side edge in accordance with each thickness. CONSTITUTION:A plate width of a plate material is made to have a dimension of pi(D2-t2)+b, and D2 is an outside diameter target value of a thick part 3, t2 is a thickness of the thick part 3, and (b) is an allowance and b=(0.5-2)t2 or so. With respect to this plate material, first of all, only both its end parts are bent by a press bender of a tool. Subsequently, its side edge part is cut out to widths B2, B1 so that a length of the outside circumference of the thick part 3 and a length of the outside circumference of a thin part 2 become S2=piD2, and S1=piD1 (D1 is a target outside diameter of the thin part), respectively. Next, a pipe 14 is formed by holding in the outside diameter widely by using a tool 13 for detaining a pipe and making the butt part contact, and a different thickness pipe 1 is obtained by welding.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) This invention relates to a method for manufacturing a metal tube having a wall thickness that varies in the longitudinal direction of the tube.

In recent years, the development of 115 bottom oil ITJ (including Kass■) has gradually become deeper and deeper. Conventionally, a fixed production plant form in which a structure is fixed to the Wij bottom has been used to produce oil (including scum) from 7113 bottom oil [1]. However, due to the increase in water depth, the beam structure
The plastic form was devised. Tension Leg Blanc I No. 1 is an example.

The tension leg plant form consists of a large number of gll
! M'j 4-shaped members are screwed together, so-called tensile legs, and there are 17 lengths in the 1/2 inch diameter.
The boat is moored to a part of the anchor at the bottom of the jlij. This tubular member is manufactured with a medium length (usually around 12 m),
Are there male screws (bottle part) and female thread part (pin part) on both ends, or are there screws (811) on both ends (connector part) to ensure the strength of the oshi part? It's thicker than the i-7. During the period of use, the F-form of the production bra is subject to the ever-changing forces of wind, waves, and tidal currents, and requires partial control in seawater. .

(Sub'A!: Technology) For example, in the production of tension reflex materials, a part of the connector between the bottle part and the main part is made of a forged product, and the t+'-i pipe part in the middle is made of a forged product. In anticipation of quality deterioration in the welded area, the wall thickness at both ends was increased by a certain length. The connector 81 is manufactured by molding and welding a direct compensation part with a wall thickness
) and circumferential welding method, 8 can be found.

(The highlight of the invention) This invention is a metal f4 having a wall thickness difference in the longitudinal direction as described above.
The purpose is to provide a method for manufacturing Jh with high precision and at low cost. For this purpose, the inventors first filed a patent application in 1982-1.
Although we have proposed 84fi88, there are still problems that need to be improved in this proposal. That is, the plate 1 in the longitudinal direction
When a metal plate of a constant width with a gap is bent with a constant pipe inner diameter, the outer circumference of the jV thick circular part is insufficient for the full circular part, so the pipe diameter changes in the length - L direction, and the thick wall part becomes thinner. Both departments [
There is a drawback that the accuracy of the 4 method is poor because the outer diameter as the J mark cannot be determined.

This invention solves the problems mentioned above. 11.1 yen [J
It is an object of the present invention to provide a method for manufacturing a metal tube having a wall thickness difference in the longitudinal direction with high precision and matching the marker 16.

(Structure and operation of the invention) The gist of the present invention to achieve the above objects is as follows: Bo/′ using the temporary phase
When molding into a body having a thickness of 1511 parts (y) of the flesh part ν in the axial direction using a die and a die, after considering the preforming of the side edges of all the boards, the thickness of each The side edge of the metal plate was set at 9J so that when gold 14 temporary with different parts was formed into a cylindrical shape, the thickness was marked and the width was set so that the target outer circumference value of each tube was achieved. Later, metal jH with a wall thickness difference in the Qa length - 1 direction was created by forming it into a cylindrical shape.
In addition, in the present invention, in the configuration described in I-, after forming into a cylindrical shape, in the final welding, the temporary welding is performed using a constrained die. It is necessary to compare the
'Jru.

In the following, this generation will be explained in detail.

First, the conventional manufacturing method and its problems will be explained. Preparation! 1'l'' is the thickness L+' as shown in No. 11;4.
It consists of a thin-walled part 2 with rt and a thick-walled part ra+3 which overhangs to the outside (4 side) and has a thickness L2. and Illfu)
In order to manufacture this, first, the plate material 4 shown in FIG. The length of 4 and 4 is equal to the length y of the manufacturing difference 7n'', and the plate width B is the neutral plane (the surface that does not expand or contract in the circumferential direction) of the thin section 2. ) The plate material 4, which has been provided with a groove in this way, is cut into various widths in the longitudinal direction along the circumference J1 and placed on a beveling layer. It is formed into a compact shape by bending, and welding at the joints is no longer possible.

However, in this manufacturing method, -C has the following problems. That is, the thick wall portion 3 of the differential thickness tube 1 formed and welded in this manner. The outer diameter of the thin portion 2 is not necessarily equal to the target outer diameter. The reason for this is explained as follows.

, First, the plate width B of the plate material 4 is the difference in thickness shown in FIG. Assuming a diameter r of 1+i N at the center of the thin wall portion 2 of 41, B=2πr is determined based on its circumference. However, because
What is this plate width B (i.e., neutral surface circumference)? 6 The relationship between the outer circumference length actually changes depending on the plate thickness, material strength, 9 bending curvature, etc., so when forming a plate material 4 having a thick wall portion 6 and a thin wall portion 5, it is necessary to change the target outer circumference length for both parts. It is not easy to determine the plate width B such that In addition, from the plate material 4 with a constant root width B, the difference JNi in the diameter R1 of the small-seven surface 1'
If you can save money, it will be thick! 3 + +ζ
Meat 81 (circumferential direction φ in the direction of plate 117 of 2/!1 is inside as shown in the figure) 11? The strain on the inner and outer surfaces of the thick inner part 3 is -ε1, respectively.
, +62. In other words, in the circular part 3 of the plate IV, a uniform circumferential stretch pattern must be formed in the direction of the plate IV force. This is difficult because the thickness Jv differs in one direction (t<r) and the relative cross-sectional area differs, and the uniform elongation of the thick portion 3 becomes smaller than the above.

Therefore, the outer diameter of the thick wall portion 3 of the actually obtained differential thickness tube l is smaller than the standard value by 1'', and the inner diameter is also smaller than that of the thick wall portion 3 and the thin wall portion 2.
It does not become a turn. That is, if a plate material 4 having a uniform plate width B in the longitudinal direction is used at the stage of preparing the material C, it is not possible to obtain the differential thickness tube 1 having the target =J method.

To solve this problem, at the stage of preparing the material, allow a certain margin for the plate width B relative to the target outer diameter, and at the stage when forming has progressed to a certain extent, set the pipe circumference to the standard outer circumference value of T1. All you have to do is cut it.

The 'f-order of the present invention will be explained below.

The board material 4 to be prepared is the same as that shown in Fig. 2, but the board width B is B=
It has a dimension of π(D2-t2)+b. Here, D2 is the target value of the outer diameter of the thick wall portion 3, t2 is the wall thickness of the thick wall portion 3, and b is a margin, and a margin of approximately b = (0, 5 to 2) t2 is provided. . The plate material 4 prepared in this way is
First, only both ends of the plate are bent using the press bender of the tool shown in the figure, so that the shape shown in FIG. 6 is obtained. Next, this material has an outer circumferential length S2−πD2 (D2
: Thick wall part [1 nominal outside diameter), : 4 Outer circumference length of wall part 2 Sl = π
D.

(D+: target outer diameter of thin wall part) width B2.
'B, is cut out. At this time, it is not necessary that B,=S,
, B2 = S2. The reason for this was previously explained in detail as a problem.

Furthermore, the width of the plate thickness changing portion 11 is shown in FIG.
Like a scrap, (1゛) Follow the outside change, (b) Connect the thick part and the thin part straightly or smoothly, ()・) Place the father history point on the change part, 1, It is decided to tie it loosely so as to hold it, cut off the irregular part, and then form it into a tubular body as shown in Fig. 8.

・The reason for cutting out the main part is not only to adjust it because it has B1 to B2 inside, but also because the root end is difficult to bend when the board is bent, so when this part becomes a tube, it will not be perfectly round. This is also to prevent the condition from worsening.

Also, the principle 111 of changing the width like (/・) in 1-tfI71)'4 is, for example, like the above-mentioned (a) and (b)! (1) When molding plates with different thicknesses, the plate JV
The effect of the change extends to its surroundings, and outside the vicinity ('
f also changes. Therefore, this influence is also Y, pj
Therefore, it is necessary to change the plate width.

(2) Finally, due to temporary welding, when the plate ends are butted together, as shown in Figure 8, the gap change 12 of the butt surface is B (<, in order to make the plate ends contact like - This requires a large load, and in some cases the tube itself deforms before the butt is made.

Therefore, it is necessary to change the plate width somewhat smoothly.

However, the shapes of these plate ends should be selected based on (1) target pipe diameter accuracy, (2) butt welding accuracy, and (3) butt work accuracy, and are not necessarily limited to -. . Therefore, when pipe diameter accuracy is strictly required, it may be necessary to make the change in plate width sharp, and in this case, it may be impossible to butt the plates with a normal tool.

At this time, 5) a tool 13 for restraining the pipe as shown in FIG. 9(a) is used. By broadly enclosing the outer diameter of the tube 14? The abutting parts can be brought into contact without deforming the eyes. Further, for simplicity, a tool 15 as shown in (b) may be used, or a pad may be used.

Next, the punch shown in Figure 3 has a length of V and a shape of 1" in the direction.
If a tool like this is used, the inner surface of both the thick and thin parts is formed with a ring having a constant curvature, so after forming it into a tubular body, the springs of both parts are Due to the difference in hang, the curvature of the thick wall g1 is generally small, as shown in FIG. 8, and this has the disadvantage that the change in the gap between the abutting surfaces becomes large.

To solve this problem, as shown in Figure 10, thick 8B
It is necessary to change the tool size of ``A+ meat 81'' according to the difference in each plate thickness and target curvature spring hang amount.By using such a tool, ＠Finally, the forming at the time of butting becomes easier, and the precision of temporary welding is improved.

(Effect of invention) L! -1-/l- According to the invention method, a metal with a wall thickness difference in the longitudinal direction whose pipe diameter in the longitudinal direction matches the precise calm < lJ target value! The result was a Noh performance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a differential thickness tube manufactured by the method of the present invention;
No. 21Δ is a perspective view of the plate material before bending, FIG. 7FTJ3 is a perspective view showing an example of the punch 7 and die 8 of the press henter used for bending, and FIG. 4 is a cross-sectional view of the differential thickness pipe.
FIG. 5 is a cross-sectional view of the tubular body immediately after bending, and FIG. 6 shows the shape of the plate immediately after engineering, and the dotted lines indicate the cutting lines. 7th
Figure (a) is an enlarged view of the end of the plate in Figure 6, and Figure (b) shows three typical examples of more detailed cutting lines of the plate thickness changing portion 15. Figure 8 is a top view of the tubular body immediately after molding, Figure 91
Δ(a) and (b) are examples of shapes of constrained tools. 1st
Figure C-1) and C-1) show an example of a tool with different curves in the thick and thin parts. ■...Differential thickness pipe, 2... Thin wall part of the pipe, 3... Inside the pipe thickness, 4... Plate material, 5... Thin wall part of the plate, 6... Inside the plate thickness, 7... Punch, 8...Dice, 9,9'...Cut green, 10...P-no-discard unnecessary part, 11...Plate thickness change part, 12...Gap between butt surfaces, 13.15. ...Restricted type tool, 14.18...Tube. Patent Applicant Representative Patent Attorney Tomoyuki Yan (and 1 other person) IE Figure 2 Figure 3

Claims (2)

[Claims] (1) Using a metal plate having a rectangular 'F m] with a relatively thick part corresponding to the meat part, the meat J is cut in the axial direction by a tool consisting of a punch and a die. , have different parts of V? When forming a metal plate into a shaped body, after completing the preforming of the side edges of the metal plate, the metal plate has parts with different thicknesses. After shaping the side edges of the metal plate so that it has a width corresponding to each thickness so that it has the target outer circumference value of 1 when formed into a cylindrical shape, the metal plate is formed into a cylindrical shape. A method for producing metal scrap having a difference of J゛1 in the longitudinal direction. (2) Consisting of a punch and a die, using a metal plate material with a force-shaped rat surface with a relatively thick portion corresponding to the inside of the bond] When forming a tubular body with different parts, after completing the preforming of the side edge of the metal plate, the target outer circumference of each tube is determined when the metal plate with different thicknesses is formed into a cylindrical shape. After cutting the side edges of the metal plate to have a width corresponding to each thickness such that the width is 1ri, the metal plate is formed into a cylindrical shape. (・A method for producing metal scraps having thickness differences in the longitudinal f direction, characterized in that one part is butted.