JPS60152319A - 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 forming a metallic plate material to a tubular body by using a punch and a die whose curvature is different in a thick part and a thin part of the metallic plate material, cutting out an unnecessary part of a side edge part of the thick part, and executing a butt welding. 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 about (0.5-2)t2. The plate material is formed to a tubular body by a punch and a die whose curvature is different in the thick part 3 and a thin part 2. Subsequently, it is cut out to widths S2, S1 by a dotted line 11 so that the outside circumferential length of the thick part 3 and the outside circumferential length of the thin part 2 become S2=piD2, and S1=piD1 (D1 is a target outside diameter of a thin part), respectively. Next, a pipe 13 is pressed by a constrained type die 12, welding is executed by butting a welding part, maintaining a desired sectional profile, and a different thickness pipe 1 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a metal tube having wall thickness differences in the longitudinal direction of the tube.

In recent years, the development of offshore oil fields (including Kasu [11]) has gradually become deeper in the ocean. Conventionally, fixed production plant forms, in which structures are fixed to the seabed, have been used to produce oil (including gas) from offshore oil fields. However, as the water depth increased, a flexible structural production plan (form) was devised.

Tension Leg Praso I Form is one example.

Tennyon leg plant form is made of a large number of steel! r
The production plan h form, which is floating in the sea, is moored to a part of the seabed anchor by so-called tension legs made of Qli materials. This f4-shaped member is manufactured with a unit length (usually about 12 m), and is provided with a pin part) and a female screw part) at both ends, but in order to secure one strong screw g1j, The tube wall is thicker at both ends (connector part). During the period of use, the production plant form changes from time to time due to wind power,
In response to wave force, tidal current force, and tidal force, the tubular member is required to have a fatigue strength of 1 minute in 1 tr water.

(Conventional I Part 1:j) As a way to solve this problem, for example, in manufacturing tension leg materials, part of the connector for the pin part, port, and box part is made of a forged product, and the straight pipe part in between is welded. In anticipation of quality deterioration in the straight pipe section, the wall thickness at both ends of the straight pipe section is thickened by a certain length to form a straight pipe section with a difference in wall thickness in the pipe length direction.
One possible method is to manufacture it by welding and weld it to a part of the connector circumferentially.

(Objective of the Invention) The present invention aims to provide a method for manufacturing the above-mentioned metal tube having thickness differences in the longitudinal direction with high precision and at low cost. For this purpose, the inventors previously filed a patent application in 1984-184.
688 was proposed, but this 4. Plan V still has the following problems that need to be improved. In other words, when a metal plate of a constant width with different plate thicknesses in the longitudinal direction is bent with a constant pipe inner diameter, the outer circumference of the thicker part becomes insufficient compared to the thinner part, resulting in a change in the pipe diameter in the longitudinal direction, resulting in a change in the thickness. There is a drawback that the standard outer diameter cannot be obtained for both the wall portion and the thin wall portion, resulting in poor dimensional accuracy.

The present invention aims to solve the above-mentioned problems and provide a method of manufacturing a metal tube having a tube diameter that matches a target value and having a wall thickness difference in the longitudinal direction with high precision.

(Structure and operation of the invention) However, the main point of the present invention for achieving objective 1-Ll is the following! l Meat 7? The part corresponding to ++ in Japanese is I','
When forming a part with a wall thickness of 1 in the axial direction of 7 into a 44'11-shaped body using a metal plate 2 consisting of a punch and a die, 11 (Make a metal plate into a tubular body using different punches and dies) After punching, make the tube outer circumference as a mark of 1" corresponding to each part of the meat. , after taking the spine at the lateral edge l)j, '-trough 1'? This is a manufacturing cut for three genus bonds with a thickness difference of j'' in the % length F direction, where the +i part is also in contact with δ.

In addition, when welding the -C1 butt Sl in the configuration 1, in Unexploited 1 and 1, the part to be welded is poked and pierced while moving the cross-sectional profile of the compact using a restraining type Guinu (lj l Welding can also be done in 8 holes (2 and 1).
1 addition 111・ru.

J Eno, 1・Ni this issue 1] 1j, i'fMI+ theory I
JI.

'1t'-1 Sub-1 (I will explain from the reconnaissance method and its problems. The pipe 1 to be manufactured is shown in Fig. 1) with a thin wall part 2 having a thickness tl and an overhang on the outer diameter side. J9 with Tajunsa L2
It consists of a meat part 3. 1- In order to manufacture a metal tube 1 having a wall thickness difference in the longitudinal direction (Jut' difference in thickness 11 and IIJ), a plate material 4 79 shown in FIG. 2 is first provided. The length L of the plate material 4 is equal to the length of the difference thickness '1↑l to be manufactured, and the plate width B is the thin wall + v 2 [1 standard medium b i1'ii
(Shrinking in the circumferential direction) - A flat surface) The circumferential length is determined to have a uniform width in the longitudinal direction, and the edge of the plate is added by 1. Is the handled month 4 prepared in this way shown in Figure 3 by a small brace or a roll feeding bend? It is formed into a shape and the joints are welded or laminated.

However, the following problems exist in this manufacturing method. That is, the outer diameter of the thin-walled portion 2 of the differential thickness tube 1 formed and welded in this way is L'j, which is not necessarily equal to the target outer diameter.The reason for this is is explained as follows.

The board width B of the V-shaped board 4 is 4th M d/1. j
I'/"1', ' Assuming the radius r of the 11th surface N of the 7th equal thickness part 2 of 1, B = 2πr is determined based on the circumference j2<. However, this plate width B ( That is, middle 3'
f-plane circumference 1<) (The relationship between the circumferences actually changes depending on the plate thickness, material strength, bending curvature, etc.) When cutting, it is not 'j-r' to determine the board width B that allows the outer circumference length of both the inside and the inside to be changed.
From the fixed plate 4 to Xh'r 4 IA, "inner surface"
lfi! The difference in R1 is 7iI, and l is 14 (the thickness is the thick wall part 3, 7;, the circumferential direction φ't' in the plate thickness direction inside the thickness of Ii), and h is the neutral plane N as shown in the figure. On the inside and outside of the bar forceps 1, there is an elongation, and the inner and outer u'ii of the thick walled part 3 are as follows: ·~ε1, +ε2. That is, in the thick interior 3, a uniform circumferential elongation pattern must be created in the plate thickness direction. However, in actual molding 11Jj, the fact that such uniform elongation occurs at the same time as bending is due to the fact that the wall thickness differs in the l-1-]'' direction and that the coarse columnar section i+'ii product This is difficult due to the difference, etc., and the uniform elongation of the thick inner part 3 is smaller than that of the standard.

Therefore, the outer diameter of the thick wall portion 3 of the actually obtained differential thickness tube 1 is smaller than the standard value, and the inner diameter of the thick inner portion 3 and the bore wall portion 2 must be the same. In other words, the material be'i 1l
A plate with a uniform plate width B in the longitudinal direction at the stage of ifi, 1
4, it is not possible to achieve the target differential thickness tube l with the 1 method.

To solve this problem, at the material base + III stage, [
Leave enough margin in the plate width B for the outer diameter of the j mark,
At the stage when the molding has formed a certain amount of holes, the tube circumference is set to 1.16 (+
(It is good to have lJJ disconnection J2 so that it is i.

Hereinafter, the first embodiment of the present invention will be explained.

・+((The board material 4 to be bent down is the same as in Fig. 2, or the board width B
has the \1 modulus of B-π(D2-t2)+b. Here D
2 is the standard value [] of the outer diameter of the thick wall portion 3, and t2 is the thick wall 1'fl!
3 wall thickness, b is the allowance, b - (0,5~2)
There is a margin of about t2. The plate material 4 thus flattened is formed into a tubular body using a punch with different curvatures in the thick and thin parts shown in Fig. S6 and the same die shown in Fig. 3. In this case, the dimensions of the thick part and the thin part are determined by the thickness of the thick part, the target curvature, the thickness of the thin part, and the difference between the thickness of the thin part and the sprue. Rather, it is determined.

Next, this phase material is added to the outer circumferential length s2-πD2 of the thick wall portion 3.
1 width S2 as shown in FIG.
, S, νj is taken by the liner line 11.

To cut out the unnecessary part at this time, adjust the width or IJ
When the board is bent not to the target but to , 411, the board edge a1
+ is difficult to bend, and when this part becomes a pipe, it is also to avoid becoming a perfect circle or a core.

Moreover, when the curvatures of the J'f thick part and the thin wall part of the -1 tool are each set to an appropriate value of 1, the J'f part and the thin part of the -1 tool form a substantially straight line in the direction of the Gino live wire beam, making the pJ removal work easier. However, it may not necessarily be a straight line, and both ends may not come into contact uniformly in the longitudinal direction during the next butt welding. In this case, it is effective to butt with a die on the restraining wall as shown in FIGS. 8(a) and 8(b). In (a), '1713 is l1ll I with the constrained die 12 that has a curved surface meter.
[;L, in (b), a tube 15 is formed with a die 14 having a V-shaped surface.
The parts to be welded are butted against each other while maintaining the desired cross-sectional profile, and the parts are welded after cutting the plate.

Also, the difference in curvature between the thick and thin parts of the tool shown in Figure 6 can be processed in the longitudinal direction, or the tool can be fabricated based on the curvature of the thin part and the liner can be attached to the thick part. The curvature may be adjusted accordingly.

(Effects of the Invention) According to the method of the present invention described in 1 below, it is possible to obtain a metal tube having a diameter in the length-L direction with good viscosity matching the target value of 1'' and a wall thickness in the longitudinal direction. It became KanJ Noh.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a differential knob pipe manufactured by the method of the present invention, Fig. 2 is a perspective view of a [jl] plate material being bent, and Fig. 3 is a perspective view of the punch 7 of a press venter used for bending. A perspective view showing an example of the die 8, FIG. 41 is a sectional view of the differential Jy tube, FIG. 5 is a sectional view of the tubular body immediately after bending, and FIG. An example of a punch shape with different curvature inside z, Fig. 7 shows a tubular body immediately after bending.
The map and true trace are of Enshi! , lJ take line 71<. 8th
1 (a) and (b) are the restraint type 1 used in the present invention.
- An example of its shape is shown. 1...Difference in thickness? i'1.2...'6 Thin wall part, 3... Thick wall saving r: 1+. 4... Plate material, 5... Plate thin wall part, 6... Plate thickness inside, 7
...Ponona, 8, evening fs, 9,9'...linori line, 10...su J4 old part, II...l) J'
J Ily guest spring, 12.14... Nigu, 13.15.
...'11゜Tokushu'1 out 1gfi person Agent j1゛Spirit Juya j'i Tomoyuki (and 1 other person) Fig. 1 Fig. 2 Pole Fig. 3

Claims (3)

[Claims] (1) Pipe thick wall 7: A rectangular plane with 17 portions corresponding to Xi/1 relative to 1i is formed using a tool consisting of a punch and a die using a metal plate material in the axial direction. When forming different parts of the metal plate into a tubular body, after forming the metal plate material into a '6-shaped body using a notch and a die with a curvature of W at the thick inside and thin wall part of the +iii curved plate material, There are 11 markers corresponding to each thick part! Manufacture of a metal tube with a wall thickness difference in the direction of the pipe length f, characterized in that after cutting out the four edges on the side edges so that the outer length is the same as d, the abutting portions are welded. Method. (2) 'Ft'J,'i A rectangular metal plate with a relatively thick part corresponding to the meat part and a tool consisting of a punch and a quiz are used to measure the wall thickness in the axial direction. When forming into a tubular body having a portion marked W, after forming the metal plate material into a tubular body using a punch and die with different curvatures for the thick interior and thin wall portion of the metal plate material described in 111, After removing 9 unnecessary parts from the side edges so as to have the outer circumference of the pipe that will be used as the mouth frame, use a restraining die to butt the welded parts while maintaining the cross-sectional profile of the molded product. , a method for manufacturing a metal tube with wall thickness differences in the longitudinal direction, characterized by temporary welding. (3) The method of applying punches and dies with different curvatures to the thick and thin parts of a metal plate material is achieved by allowing a liner to be placed on the tool surface, Claims 1 and 2. 1. The method for manufacturing a metal tube according to item 1.