CN116568417A - Welded pipe and method for manufacturing welded pipe - Google Patents

Abstract

The welded pipe (1A) is a first end portion (10A) located in the bending direction and a second end portion (20A) located on the opposite side of the first end portion (10A) of a plate-shaped body (2A) to be bent into a tubular shape aligned and welded to the first end portion (10A) and the second end portion (20A). The first end portion (10A) has: a first end face; a first face portion formed by a portion of the outer wall surface (102) of the plate-shaped body (2A) on the side of the first end face; and a first step, which Formed by the first surface being recessed towards the inside of the tube, the second end portion (20A) has: a second end surface; a second surface, which is located on the second end surface of the inner wall surface (101) of the plate-shaped body (2A) The part of the side is formed, and is aligned with the first face that the first end portion (10A) has; department.

Description

Welded pipe and method for producing welded pipe

technical field

The present disclosure relates to welded pipes and methods of manufacturing welded pipes.

Background technique

A welded pipe is manufactured by bending a metal plate into a pipe shape, aligning its ends to form a seam, and welding the seam. Among such welded pipes, there is a welded pipe in which a recess is provided in a seam so that a weld seam formed during welding is prevented from protruding toward the inside of the pipe.

For example, Patent Document 1 discloses a welded pipe having a concave portion that gradually becomes deeper toward a joint. In the welded pipe described in Patent Document 1, the weld seam formed when the seam is welded is formed in the concave portion. Therefore, the weld seam is less likely to protrude to a position closer to the inside of the tube than the tube inner wall adjacent to the concave portion. In the past, a pipe expansion tool was sometimes inserted into the welded pipe for processing. The welded pipe described in Patent Document 1 is provided with the above-mentioned structure, and in such a case, generation of cutting chips due to cutting of the weld seam by the pipe expanding tool is suppressed.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Publication No. 3-106206

Contents of the invention

The problem to be solved by the invention

However, in the welded pipe described in Patent Document 1, the end surfaces of the metal plates are aligned, and the end surface portion having a small end surface thickness is welded. Therefore, there is a concern that sufficient welding strength cannot be obtained.

The present disclosure was made in order to solve the above-mentioned problems, and an object of the present disclosure is to provide a welded pipe and a method of manufacturing a welded pipe that suppress the protrusion of the weld seam inwardly of the pipe and have high welding strength.

means to solve the problem

In order to achieve the above object, the welded pipe of the present disclosure aligns the first end portion located in the bending direction and the second end portion located on the opposite side of the first end portion of the plate-shaped body bent into a tubular shape, and aligns the first end portion A welded pipe formed by welding the first part and the second end part. In the welded pipe, the first end portion has: a first end surface; a first surface portion formed by a portion of the outer wall surface of the plate-shaped body on the first end surface side; and a first step formed by the first surface. It is formed by indenting towards the inner side of the tube. The second end portion has: a second end face; a second face portion formed by a portion of the inner wall face of the plate-like body on the second end face side and aligned with the first face portion of the first end portion; and and a welding portion by which the second end surface is welded to the first surface portion of the first end portion.

Invention effect

According to the configuration of the present disclosure, the second end portion has a second surface portion formed by a portion of the inner wall surface of the plate-shaped body on the second end surface side and aligned with the first surface portion of the first end portion. and a welding portion, by which the second end surface is welded to the first surface portion of the first end portion. Therefore, it is possible to suppress the protruding of the weld bead formed in the welded portion into the inside of the pipe. In addition, welded pipes have higher welding strength.

Description of drawings

FIG. 1 is a perspective view of a welded pipe according to Embodiment 1 of the present disclosure.

Fig. 2 is a developed view of a welded pipe according to Embodiment 1 of the present disclosure.

FIG. 3 is an enlarged view of a region III shown in FIG. 1 .

Fig. 4 is a sectional view taken along line IV-IV shown in Fig. 2 .

5 is a flowchart of a method of manufacturing a welded pipe according to Embodiment 1 of the present disclosure.

6 is a conceptual diagram of a calender roll used in a step of forming a plate-shaped body included in the method of manufacturing a welded pipe according to Embodiment 1 of the present disclosure.

7 is an enlarged perspective view of a modified example of the welded pipe according to Embodiment 1 of the present disclosure.

8 is a perspective view of a welded pipe according to Embodiment 2 of the present disclosure.

9 is a developed view of a welded pipe according to Embodiment 2 of the present disclosure.

FIG. 10 is an enlarged view of the X region shown in FIG. 8 .

Fig. 11 is a cross-sectional view taken along line XI-XI shown in Fig. 9 .

12 is an enlarged perspective view of a modified example of the welded pipe according to Embodiment 2 of the present disclosure.

Detailed ways

Hereinafter, the welded pipe and the method of manufacturing the welded pipe according to the embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, in the drawings, the same reference numerals are assigned to the same or equivalent parts.

(Embodiment 1)

The welded tube of Embodiment 1 is a welded tube with inner surface grooves used in a heat exchanger. The welded pipe is manufactured by bending a metal plate into a tubular shape, and aligning and welding both end portions of the metal plate. In such manufacture, steps are provided at both end portions of the metal plate of the welded pipe in order to facilitate alignment of both end portions.

First, the structure of the welded pipe will be described with reference to FIGS. 1 and 2 . Next, the configuration of the steps at both ends will be described with reference to FIGS. 3 and 4 .

FIG. 1 is a perspective view of a welded pipe 1A according to Embodiment 1. FIG. FIG. 2 is a developed view of the welded pipe 1A. In addition, in FIG. 1, only the pipe end part of the welded pipe 1A extended in the axial direction AD is shown for easy understanding. In addition, the welding portion 30A is omitted. In addition, in FIG. 2, the expanded welded pipe 1A seen from the inner wall surface 101 side is shown.

As shown in FIG. 1 , a welded pipe 1A includes a plate-shaped body 2A bent into a circular pipe shape.

As shown in FIG. 2 , the plate-like body 2A is formed of a strip. Here, in this specification, a strip refers to an elongated metal piece having a rectangular cross section or a strip-shaped metal piece. In FIG. 2, although only a part of the strip is shown, the strip extends in the direction of the arrow A1. And, the length of the strip is longer than the width W of the strip.

In addition, in order to improve heat transfer, the plate-like body 2A is formed of copper, more specifically, phosphorus-deoxidized copper or oxygen-free copper with high purity and low oxide content. Also, as shown in FIGS. 1 and 2 , the plate-like body 2A is formed with a plurality of grooves 3 to improve heat transfer from the refrigerant when the refrigerant flows. As a result, protruding fins 4 are formed between the grooves 3 . In order to stir the refrigerant by the fins 4, the grooves 3 are inclined with respect to the width direction WD as shown in FIG. 2 .

The plate-shaped body 2A is curved in the width direction WD so that the surface on which the groove 3 is formed faces inward, that is, the surface on which the groove 3 is formed serves as an inner wall surface 101 . And, the both end parts in the width direction WD overlap. Thus, the plate-shaped body 2A forms the welded pipe 1A shown in FIG. 1 . Steps 13A, 23A are formed at both end portions of the plate-shaped body 2A in order to facilitate alignment of both end portions when forming the welded pipe 1A. Next, steps at both end portions of the plate-shaped body 2A will be described with reference to FIGS. 3 and 4 .

FIG. 3 is an enlarged view of a region III shown in FIG. 1 . Fig. 4 is a sectional view taken along line IV-IV shown in Fig. 2 . In addition, in FIG. 3, unlike FIG. 1, the welding part 30A is shown in figure. In addition, in FIG. 4 , the welded pipe 1A is shown in a state where the inner wall surface 101 is on top and the outer wall surface 102 is on the bottom.

As shown in FIG. 3 , the plate-shaped body 2A has a first end portion 10A and a second end portion 20A which are overlapped with each other by bending the plate surface into a circular tube shape. In addition, these 1st end part 10A and 20A of 2nd end parts refer to the end part located in the bending direction BD of the plate-shaped body 2A.

In the first end portion 10A, as shown in FIG. 4 , the outer wall surface 102 on the end surface 11A side is recessed toward the inner wall surface 101 side. That is, the outer wall surface 102 is dented toward the inside of the pipe. As shown in FIG. 3 , this is to make the second end portion 20A easily fit into the first end portion 20A when the welded pipe 1A is formed by overlapping the inner wall surface 101 of the second end portion 20A with the outer wall surface 102 of the first end portion 10A. The recesses of the end portion 10A are arranged in coincidence with each other. In addition, the inner wall surface 101 refers to the surface on which the bottom of the above-mentioned groove 3 is provided.

As shown in FIG. 4 , the first end portion 10A is formed by denting the outer wall surface 102 on the end surface 11A side toward the inner side of the tube to form a gap between the surface 5 located in the center of the width direction WD of the outer wall surface 102 and the outer wall surface 102 side located on the end surface 11A side. There is a step 13A between the surfaces 12A. In addition, since the surface 12A overlaps with the second end portion 20A, there is no structure forming concavo-convex, and it is flat when unfolded as shown in FIG. 4 .

On the other hand, since the second end portion 20A overlaps the first end portion 10A from the outside of the tube, the inner wall surface 101 on the side of the end surface 21A is recessed. Specifically, the inner wall surface 101 on the side of the end surface 21A is recessed toward the outside of the tube opposite to the portion having the step 13A of the first end portion 10A described above. Thus, the second end portion 20A has a step 23A between the surface 6 located in the center in the width direction WD of the inner wall surface 101 and the surface 22A located on the end surface 21A side of the inner wall surface 101 .

In order to make the second end portion 20A fit with the first end portion 10A, the width W2 of the second end portion 20A, that is, the distance from the step 23A to the end surface 21A, is the same as the width W1 of the first end portion 10A, that is, the distance from the step 13A to the end surface 21A. The distances from the end faces 11A are the same.

In addition, in order to make the second end portion 20A not protrude to the outside of the pipe from the portion of the first end portion 10A closer to the end surface 11A than the step 13A when the second end portion 20A is aligned with the first end portion 10A, the second end portion The thickness T2 of the portion 20A is the same as the height H1 of the step 13A of the first end portion 10A. In addition, the surface 22A located in the second end portion 20A is flat so that it overlaps with the first end portion 10A, and there is no structure forming concavities and convexities, and is flat when unfolded as shown in FIG. 4 .

In addition, in order to make the first end portion 10A not protrude toward the inner side of the tube from the portion of the second end portion 20A closer to the end surface 21A than the step 23A when the second end portion 20A is fitted to the first end portion 10A, the second The height H2 of the step 23A of the end portion 20A is the same as the thickness T1 of the first end portion 10A.

As shown in FIG. 3 , the second end portion 20A overlaps the surface 12A of the first end portion 10A at a distance of 7 from the step 13A of the first end portion 10A. The width W7 of the space 7 is 1/2 of the width W1 of the above-mentioned first end portion 10A or 1/2 of the width W2 of the second end portion 20A. In addition, the overlapping width W3 of the first end portion 10A and the second end portion 20A is 1/2 of the width W1 of the above-mentioned first end portion 10A or 1/2 of the width W2 of the second end portion 20A.

The dimensions of such first end portion 10A and second end portion 20A are determined for the following reasons. Explaining this reason in detail, when the welded pipe 1A is formed into a desired pipe outer diameter or pipe inner diameter, there may be an error in the width W dimension of the plate-shaped body 2A shown in FIG. The relative position of the end portion 20A relative to the first end portion 10A is shifted. As a result, sometimes the second end portion 20A cannot be aligned with the first end portion 10A. Regarding the first end portion 10A and the second end portion 20A, by setting the width W1 of the first end portion 10A to a value larger than the maximum value of the error in the size of the width W generated, and at the position of the first end portion 10A The first end portion 10A and the second end portion 20A are reliably aligned by arranging the end surface 21A of the second end portion 20A at the center in the width direction WD of the surface 12A, and thus formed in the above-mentioned dimensions. Alternatively, regarding the first end portion 10A and the second end portion 20A, by setting the width W2 of the second end portion 20A to a value larger than the maximum value of the error in the size of the width W generated, and at the second end portion The end surface 11A of the first end portion 10A is arranged at the center of the width direction WD of the surface 22A of the surface 20A, thereby reliably aligning the first end portion 10A and the second end portion 20A, and thus having the above-mentioned dimensions.

In addition, the width W1 of the first end portion 10A and the width W2 of the second end portion 20A are formed to a tolerance of the size of the width W shown in FIG. When the tolerance of the dimension in the width direction WD is the same, the overlapping width W3 of the first end portion 10A and the second end portion 20A shown in FIG. 3 is 1/2 of the value of the tolerance. Thereby, even if a dimension error occurs in the width W of the plate-like body 2A, the second end portion 20A can be reliably aligned with the first end portion 10A. As a result, it is possible to prevent a gap from being generated between the second end portion 20A and the first end portion 10A, thereby preventing it from functioning as a pipe.

In addition, as for the above-mentioned tolerance, since the standard of the tolerance of the width with respect to the thickness of a strip is stipulated in the Japanese Industrial Standards, it is preferable to use the tolerance of this standard as a tolerance. For example, in the Japanese Industrial Standard JIS H3100 "Copper and Copper Alloy Plates and Strips", the tolerance of the width relative to the thickness is stipulated. Make tolerances.

On the other hand, as shown in FIG. 3 , a welding portion 30A is arranged in a space 7 between the end surface 21A of the second end portion 20A and the step 13A of the first end portion 10A.

The welding portion 30A is formed by filling a molten material between the end surface 21A of the second end portion 20A and the step 13A of the first end portion 10A. That is, the welded portion 30A is formed in which molten material during welding remains in the space 7 between the end surface 21A of the second end portion 20A and the step 13A of the first end portion 10A. Thereby, the welding part 30A welds the end surface 21A of the 2nd end part 20A and the surface 12A of the 1st end part 10A. Furthermore, the end surface 21A of the second end portion 20A and the step 13A are welded. In this welding, the formed welded portion 30A is supported by the face 12A of the first end portion 10A, so the welded portion 30A does not enter and protrude inside the pipe. In addition, when a depression is provided on the outer peripheral surface of the welded pipe 1A, stress tends to concentrate on the depression. Therefore, in order to increase the strength of the welded pipe 1A, it is preferable that the welded part 30A fills the part of the gap 7 and welds the first end part 10A and the second end part 20A.

In this way, in the welded pipe 1A, the first end portion 10A and the second end portion 20A are easily fitted. In addition, the welded portion 30A fills the portion of the space 7 , whereby the welded portion 30A joins the first end portion 10A and the second end portion 20A with high strength. Next, a method of manufacturing the welded pipe 1A will be described with reference to FIGS. 5 and 6 .

FIG. 5 is a flowchart of a method of manufacturing the welded pipe 1A. FIG. 6 is a conceptual diagram of calender rolls 200 and 300 used in the step of forming the plate-like body 2A included in the method of manufacturing the welded pipe 1A.

First, although it is not shown in FIG. 5 , prepare a strip material having the above-mentioned width W without forming structures such as grooves and protrusions on the surface. The strip material is made of phosphorus deoxidized copper or Oxygen copper is formed. For example, prepare a strip wound into a roll. Since the rolling is performed by the rolling rolls 200 and 300 described later, it is sufficient to prepare a strip thicker than the wall thickness of the welded pipe 1A to be produced in consideration of the rolling rate in this rolling.

Next, as shown in FIG. 5 , grooves 3 and steps 13A and 23A are formed in the prepared strip to form plate-shaped body 2A (step S1 ). For example, the strip pulled out from the roll is passed between the calender roll 200 shown in FIG. 6 and the calender roll 300 pressed by the calender roll 200 . Here, the calender roll 200 has concavo-convex portions 210 and convex portions 220 for forming the grooves 3 and the second end portion 20A. In addition, the calender roll 300 has a convex portion 310 for forming the first end portion 10A. When the strip passes between these calender rollers 200 and 300, the unevenness of the concave-convex part 210, the convex part 220, 310 will be transferred onto the strip. Thus, the first end portion 10A and the second end portion 20A having steps 13A, 23A are formed on the bar. As a result, the plate-shaped body 2A in the expanded state shown in FIG. 2 is formed.

In addition, when the plate-shaped body 2A in which the groove 3 and the steps 13A and 23A are formed in advance is prepared, step S1 may be omitted.

Returning to Fig. 5, next, the plate-shaped body 2A is formed into a circular tube shape (step S2). For example, using a so-called electric welding device, the plate-like body 2A is bent in the width direction WD shown in FIG. 2 with the surface formed with the groove 3 and the second end portion 20A inside. As a result, the plate-like body 2A is formed in a state where the second end portion 20A is aligned with the first end portion 10A shown in FIGS. 1 and 3 . In this molding, since the end surface 21A of the second end portion 20A is disposed at the center of the width direction WD of the first end portion 10A shown in FIG. Align the second end portion 20A with the first end portion 10A.

Next, the first end portion 10A and the second end portion 20A aligned by molding are welded (step S3 ). In detail, when the second end portion 20A is aligned with the first end portion 10A in step S2, the above-mentioned step 13A of the first end portion 10A and the end surface 21A of the second end portion 20A are formed as shown in FIG. 3 . Interval 7 shown. Therefore, the welding portion 30A is formed at the portion having the gap 7 using a welding machine included in the electric welding apparatus. During this welding, molten material remains in the entire inner space of the spacer 7 . Thus, the welded portion 30A does not enter the inside of the pipe. In addition, the welding portion 30A does not protrude toward the inside of the pipe. Furthermore, by filling up the inner space of the spacer 7 with the welded portion 30A, the weld strength is improved.

In addition, although the specific method of welding in step S3 is not particularly limited, in order to maintain the shape of the groove 3, as a welding method, compared with resistance welding, high-frequency induction heating welding, laser welding, TIG (Tungsten Insert Gas: tungsten inert gas welding) are preferred. gas protection) welding.

Next, although not shown, the portion protruding from the outer wall surface 102 of the welding portion 30A is cut off. At this time, since the welded portion 30A is formed in the inner space of the space 7 , the welding strength of the welded portion 30A can be maintained even if the portion protruding from the outer wall surface 102 of the welded portion 30A is cut off. Next, the plate-shaped body 2A formed into a circular tube shape in step S2 and welded in step S3 is reduced to a target diameter using a so-called puller. Furthermore, the circular tubular plate-like body 2A having a reduced diameter is cut to a target length, and then the shape is corrected. Through the above operations, the welded pipe 1A is completed.

In addition, in the case of manufacturing a welded pipe 1A having an outer diameter of 7.00 mm, a height of the fin 4 from the inner wall surface 101 of 0.230 mm, and a thickness of the plate-shaped body 2A at the bottom of the groove 3 of 0.290 mm, the above-mentioned first The width W1 of the end portion 10A and the width W2 of the second end portion 20A may be 0.8 mm. This is because, on the premise that the strip is rolled by an amount of 0.05 mm during the rolling by the rolling rolls 200 and 300 in the above-mentioned step S1, a phosphorus-deoxidized copper or copper strip with a thickness of 0.570 mm and a width W of 2.20 mm is used. In the case of a strip made of oxygen-free copper, the tolerance of the width W of the strip is set to ±0.4 mm in accordance with Japanese Industrial Standard JIS H3100 "copper and copper alloy plate and strip".

As described above, in the welded pipe 1A of Embodiment 1, the second end portion 20A has: the inner wall surface 101 aligned with the surface 12A of the first end portion 10A; Since the end surface 21A of the end portion 20A is welded to the surface 12A of the first end portion 10A, the welded portion 30A does not protrude into the pipe. In addition, since the welding portion 30A is formed in a state where the inner wall surface 101 of the second end portion 20A is aligned with the surface 12A of the first end portion 10A, the welding strength of the welding portion 30A is also high.

Further, in the welded pipe 1A, the welded portion 30A fills up between the end surface 21A of the second end portion 20A and the step 13A of the first end portion 10A. Therefore, the welding strength of the welding portion 30A is further improved.

Furthermore, since the welded portion 30A is formed between the step 13A of the first end portion 10A and the end surface 21A of the second end portion 20A, the welded portion 30A is less likely to protrude from the outer wall surface 102 . In addition, even if the welded portion 30A protrudes from the outer wall surface 102 and the protruded portion is cut off, the weld strength of the welded portion 30A can be maintained. As a result, the welded pipe 1A is less likely to be damaged.

The width W1 of the first end portion 10A and the width W2 of the second end portion 20A have the same size as the tolerance of the width W of the plate-shaped body 2A, and the end surface 21A of the second end portion 20A is disposed on the side of the first end portion 10A. Center in the width direction WD. Therefore, it is possible to prevent the second end portion 20A from detaching from the first end portion 10A to cause a gap or a through hole between the second end portion 20A and the first end portion 10A.

The height H1 of the step 13A of the first end portion 10A coincides with the thickness T2 of the second end portion 20A. Furthermore, the thickness T1 of the first end portion 10A coincides with the height H2 of the step 23A of the second end portion 20A. Therefore, the entire thickness of the portion where the first end portion 10A is aligned with the second end portion 20A is the same as that of the other portion of the welded pipe 1A. As a result, the welded pipe 1A is less likely to be deformed against a bending moment. That is, if the overall thickness of the portion where the first end portion 10A is aligned with the second end portion 20A is different from the thickness of the other portions of the welded pipe 1A, their thinner portions are easily deformed. However, in the welded pipe 1A, since there is no such portion, it is difficult to deform.

In addition, the welded tube 1A can be used for a heat exchanger. For example, the welded tube 1A may be assembled with fins and flow refrigerant inside it. In the welded tube 1A, the first end portion 10A does not protrude into the tube, and therefore, the tube expansion process at the time of assembling the fins is easy.

The end face 11A, the face 12A, and the step 13A of the first end portion 10A described above are examples of the first end face, the first face portion, and the first step of the first end portion described in this specification. The end face 21A, the face 22A, and the step 23A of the second end portion 20A are examples of the second end face, the second face portion, and the second step of the second end portion described in this specification. The axial direction AD is an example of the tube axis direction. In addition, the first end portion 10A and the second end portion 20A may be replaced, and the first end portion 10A and the second end portion 20A may be used as an example of the second end portion and the first end portion described in this specification.

In addition, above-mentioned step S1 is an example of the process of forming a 1st step described in this specification. In addition, step S2 is an example of the process of aligning the other surface of a 2nd end part with a 1st surface part described in this specification. Step S3 is an example of the process of welding the second end portion to the first end portion described in this specification.

(Modification)

In Embodiment 1, the material forming the welding portion 30A is filled in the entire internal space of the space 7 between the step 13A of the first end portion 10A and the end surface 21A of the second end portion 20A. In other words, the weld 30A fills up the entire inner space of the partition 7 . However, the welding portion 30A is not limited thereto. The welding portion 30A may be provided in part or all of the inner space of the compartment 7 .

FIG. 7 is an enlarged perspective view of a modified example of the welded pipe 1A of Embodiment 1. FIG. In addition, in FIG. 7 , the same region as the III region shown in FIG. 1 in the modified example of the welded pipe 1A is enlarged.

As shown in FIG. 7 , in the welded pipe 1A, the welded portion 30A may be provided in a part of the inner space of the compartment 7 . Specifically, the welding portion 30A may extend linearly along the end surface 21A of the second end portion 20A. Thus, the welding portion 30A can also join the end surface 21A of the second end portion 20A and the surface 12A of the first end portion 10A. In addition, although not shown in figure, the welding part 30A may extend along the end surface 21A of the 2nd end part 20A, and may be formed intermittently in the extending direction. This is because the inner wall surface 101 of the second end portion 20A, which is closer to the end surface 21A than the step 23A, is in close contact with the surface 12A of the first end portion 10A, thereby sufficiently functioning as a pipe.

In this way, the welding portion 30A is provided only in a part of the internal space of the compartment 7 , and as a result, only a part of the internal space of the compartment 7 may be filled. In such a configuration, the inner wall surface 101 of the second end portion 20A is also aligned with the surface 12A of the first end portion 10A, and therefore, in the welded pipe 1A, the welding strength of the welded portion 30A can be maintained in a high state.

(Embodiment 2)

In the welded pipe 1A according to Embodiment 1, steps 13A, 23A are formed in both the first end portion 10A and the second end portion 20A. Also, the end surface 11A of the first end portion 10A and the end surface 21A of the second end portion 20A are recessed. However, the welded pipe 1A is not limited thereto. Only one of the first end portion 10A and the second end portion 20A may be recessed in the welded pipe 1A.

The welded pipe 1B of Embodiment 2 is a welded pipe in which the first end portion 10B has a step 13B and the second end portion 20B does not have a step.

Hereinafter, a welded pipe 1B according to Embodiment 2 will be described with reference to FIGS. 8 to 11 . In Embodiment 2, description will focus on configurations different from those in Embodiment 1. FIG.

FIG. 8 is a perspective view of a welded pipe 1B according to Embodiment 2. FIG. FIG. 9 is a developed view of the welded pipe 1B. FIG. 10 is an enlarged view of the X region shown in FIG. 8 . Fig. 11 is a cross-sectional view taken along line XI-XI shown in Fig. 9 .

In addition, in FIG. 8, similarly to FIG. 1, only the pipe end part of the welded pipe 1B is shown. In addition, the welding portion 30B is omitted. In FIG. 9 , similarly to FIG. 2 , the welded pipe 1B is shown when the plate-shaped body 2B included in the welded pipe 1B is developed and viewed from the inner wall surface 101 side.

As shown in FIGS. 8 and 10 , the first end portion 10B is bent in a crank shape in a tube cross-sectional view, that is, in a tube sectional view. Specifically, it is bent once from the outer wall surface 102 in the direction of the tube central axis, and then bent in the direction of the tube circumference. As shown in FIG. 11 , in the cross-sectional view of the tube, the bent length of the crank-shaped bend toward the central axis of the tube is longer than the length from the inner wall surface 101 to the opening surface of the groove 3, in other words, the length from the inner wall surface 101 to the fin. The distance D of the top of 4 is small. As a result, the crank-shaped bend is formed on the outer side of the tube than the top of the fin 4 in the tube cross-sectional view. As a result, the first end portion 10B is prevented from protruding toward the inside of the tube. Thereby, for example, when the pipe expanding tool is inserted into the welded pipe 1B to expand the diameter, it is possible to prevent the pipe expanding tool from being obstructed.

Furthermore, the first end portion 10B has a step 13B by being bent into a crank shape in a pipe sectional view. Furthermore, there is a surface 12B without undulations on the side of the end surface 11B from the step 13B. In contrast, no step is formed in the second end portion 20B. In the case where the second end portion 20B has no step, when the second end portion 20B coincides with the first end portion 10B from the outside of the pipe of the first end portion 10B, the second end portion 20B may protrude to the outside of the pipe. . However, the first end portion 10B has a step 13B. As a result, such protrusion of the second end portion 20B can be prevented. In addition, in order to prevent the second end portion 20B from protruding when the first end portion 10B coincides with the second end portion 20B, in the tube cross-sectional view, the first end portion 10B is directed toward The inside of the tube is bent into a crank shape. As a result, the height H1 of the step 13B is the same as the thickness T2 of the second end portion 20B. In addition, it is the same as the thickness T1 of the first end portion 10B.

In addition, the thickness T1 of the first end portion 10B is smaller than the distance D of the fin 4 from the inner wall surface 101 to the top. Thus, the thickness T1 is set in such a state that when the second end portion 20B overlaps the first end portion 10B from the outside of the tube, the first end portion 10B does not go further into the tube than the fin 4 positioned on the second end portion 20B side. protrude.

On the other hand, as shown in FIG. 9 , the second end portion 20B is not formed with fins 4 . As a result, the surface 22B of the second end portion 20B has no undulations and is flat in the unfolded state shown in FIG. 9 . Thereby, when the second end portion 20B overlaps with the first end portion 10B, it can contact without a gap. In addition, as shown in FIG. 11 , the surface 22B of the second end portion 20B is at the same height as the bottom of the groove 3 in the pipe inner direction.

As shown in FIG. 10 , the second end portion 20B is aligned with the first end portion 10B from the outside of the tube. In addition, the end surface 21B of the second end portion 20B is arranged away from the step 13B of the first end portion 10B by an amount of a space 7 . The width W7 of this space 7 is 1/2 of the width W1 shown in FIG. 11 of the first end portion 10B or the width W2 of the second end portion 20B. In addition, as shown in FIG. 10 , a welding portion 30B is formed at the space 7 . These spaces 7 and welded portions 30B are the same as the spaces 7 and welded portions 30A described in the first embodiment. Therefore, detailed descriptions of these are omitted.

As described above, in the welded pipe 1B of Embodiment 2, the first end portion 10B is bent into a crank shape in a pipe cross-sectional view, and the second end portion 20B is aligned with the surface 12B of the first end portion 10B. Compared with the welded pipe 1A of Embodiment 1, the welded pipe 1B has no step at the second end portion 20B, and thus is easy to manufacture.

In addition, since the first end portion 10B is formed on the outer side of the tube than the top of the fin 4, it is less likely to become an obstacle during tube expansion. Furthermore, when the fluid flows in the welded pipe 1B, the first end portion 10B is less likely to disturb the flow of the fluid.

Since the welded portion 30B fills the space between the step 13B of the first end portion 10B and the end surface 21B of the second end portion 20B, the welded portion 30B does not protrude into the pipe as in the first embodiment. In addition, the welding strength of the welding portion 30B is also high. In addition, the welding portion 30B is less likely to protrude from the outer wall surface 102 . In addition, as described in the modified example of the first embodiment, the welding portion 30B is not limited to filling the entire internal space of the space 7 , and may fill only a part of the internal space of the space 7 . That is, the welding portion 30B may be provided only in a part of the inner space of the compartment 7 .

The welded pipes 1A, 1B and the method of manufacturing the welded pipes 1A, 1B according to the embodiment of the present disclosure have been described above, but the welded pipes 1A, 1B and the method of manufacturing the welded pipes 1A, 1B are not limited thereto.

For example, in Embodiment 2, the first end portion 10B is bent in a crank shape in a pipe cross-sectional view, and the second end portion 20B is straight in a pipe cross-sectional view. However, the welded pipes 1A, 1B are not limited thereto.

FIG. 12 is an enlarged perspective view of a modified example of the welded pipe 1B of the second embodiment. In addition, in FIG. 12, the same area as FIG. 10 is enlarged and displayed.

As shown in FIG. 12, in the case where the first end portion 10B is bent into a crank shape in a pipe cross-sectional view to have a step 13B, the second end portion 20B can also be formed by denting the inner wall surface 101 of the end surface 21B toward the outside of the wall. Instead, it has a step 23B. In short, it is also possible to combine the second end portion 20A described in Embodiment 1 with the crank-shaped first end portion 10B described in Embodiment 2 in a pipe cross-sectional view. Also in such an aspect, the welded portion 30B does not protrude into the pipe interior. In addition, in such an aspect, by providing the welding portion 30B in the entire internal space of the compartment 7, the welding strength can be improved. In addition, in this modified example of the welded pipe 1B, not only the entire internal space of the space 7 is filled, but only a part of the internal space of the space 7 may be filled.

In Embodiments 1 and 2, although the welded pipes 1A and 1B are circular pipes, the welded pipes 1A and 1B are not limited thereto. The welded pipes 1A and 1B should just be tubular. That is, the plate-shaped bodies 2A and 2B only need to be bent into a tubular shape. For example, the welded pipes 1A and 1B may be flat pipes.

In Embodiments 1 and 2, although the welded pipes 1A and 1B are formed of copper, the welded pipes 1A and 1B are not limited thereto. The material of the welded pipes 1A, 1B is arbitrary. For example, the material of the welded pipes 1A and 1B should just be metal, and may be aluminum or an aluminum alloy. In addition, the material of the welded pipes 1A, 1B may be resin. Even with such a material, it is possible to align the first end portion 10A, 10B with the second end portion 20A, 20B, and to weld the first end portion 10A, 10B and the second end portion 20A, 20B. In addition, when the material of the welded pipes 1A and 1B is resin, the strip material described in Embodiment 1 refers to an elongated resin sheet having a rectangular cross section or a strip-shaped resin sheet.

In Embodiments 1 and 2, end faces 11A, 11B of first end portions 10A, 10B are planar. In addition, the end surfaces 21A, 21B of the second end portions 20A, 20B are planar. However, the first end portion 10A, 10B and the second end portion 20A, 20B are not limited thereto. For example, chamfers may be formed on the end faces 11A, 11B of the first end portions 10A, 10B. Similarly, chamfered portions may be formed on the end surfaces 21A, 21B of the second end portions 20A, 20B. For example, the chamfer may be a so-called C chamfer or R chamfer. Even such a shape can be produced by the aforementioned calender rolls 200 and 300 .

In Embodiments 1 and 2, a plurality of grooves 3 are formed on the inner wall surfaces 101 of the plate-shaped bodies 2A and 2B. However, the tank 3 is not limited thereto. At least one groove 3 may be provided on the inner wall surface 101 of the plate-like body 2A, 2B.

In addition, as shown in FIGS. 2 and 9 , it is preferable that the groove 3 intersects the arrow A1 direction in which the end faces 21A, 21B of the second end portions 20A, 20B extend. It is particularly preferable to incline with respect to the arrow A1 direction in which the end faces 21A, 21B extend. This is because, even when the fluid flows in the welded pipes 1A, 1B and fluid pressure is applied to the groove 3, as long as the welded portions 30A, 30B extend along the end faces 21A, 21B, and the groove 3 and the welded portion 30A If the extending directions of 30B and 30B cross each other, the welding parts 30A and 30B will not be easily peeled off.

Various embodiments and modifications can be made to the present disclosure without departing from the broad spirit and scope of the present disclosure. In addition, the above-mentioned embodiment is for explaining this disclosure, and does not limit the range of this disclosure. That is, the scope of the present disclosure is shown not by the embodiments but by the scope of claims. In addition, various modifications implemented within the scope of the claims and their equivalent disclosures are considered to be within the scope of the present disclosure.

This application is based on Japanese Patent Application Japanese Patent Application No. 2021-3957 filed on January 14, 2021. The entire specification, claims, and drawings of Japanese Patent Application No. 2021-3957 are incorporated herein by reference.

Label description

1A, 1B: welded pipe; 2A, 2B: plate-like body; 3: groove; 4: fin; 5, 6: surface; 7: spacer; 10A, 10B: first end portion; , 12B: surface; 13A, 13B: steps; 20A, 20B: second end portion; 21A, 21B: end surface; 22A, 22B: surface; 23A, 23B: steps; 30A, 30B: welding part; 101: inner wall surface; 102: outer wall surface; 200: calender roll; 210: concave-convex part; 220: convex part; 300: calender roll; 310: convex part; A1: arrow; AD: axial direction; BD: bending direction; D: distance; H1, H2: height; T1, T2: thickness; WD: width direction; W, W1, W2, W3, W7: width.

Claims (13)

1. A welded pipe is formed by aligning a first end portion of a plate-like body bent into a tubular shape in a bending direction and a second end portion on the opposite side of the first end portion, and welding the first end portion and the second end portion,

the first end portion has: a first end face; a first surface portion formed by a portion of an outer wall surface of the plate-like body, the portion being located on the first end surface side; and a first step formed by recessing the first face portion toward the inside of the tube,

the second end portion has: a second end face; a second surface portion formed by a portion of an inner wall surface of the plate-like body on the second end surface side and aligned with the first surface portion of the first end portion; and a welding portion by which the second end face is welded to the first face portion provided in the first end portion.

2. The welded pipe according to claim 1, wherein,

the welding part is buried between the second end face and the first step.

3. The welded pipe according to claim 1 or 2, wherein,

the second end portion has a second step recessed from the second face portion toward the outside of the tube.

4. A welded pipe according to any one of claims 1 to 3, wherein,

the second end face is located between the first end face and the first step.

5. The welded pipe according to claim 3, wherein,

the thickness of the first end portion is the same as the height of the second step.

6. The welded pipe according to any one of claims 1 to 5, wherein,

the thickness of the first end portion is the same as the height of the first step.

7. The welded pipe according to claim 6, wherein,

the first end portion has the first step by bending the plate-like body into a crank shape toward the inside of the tube.

8. The welded pipe according to claim 7, wherein,

the welded pipe includes a plurality of grooves provided between the first end portion and the second end portion and extending in a direction inclined with respect to a pipe axis direction,

the surface of the first end portion on the inner side of the tube, which is bent into a crank-like shape, is located on the outer side of the tube than the opening surfaces of the plurality of groove openings.

9. The welded pipe according to any one of claims 1 to 8, wherein,

the welded pipe has a groove provided in a portion of the inner wall surface other than the second surface, and agitates the fluid when the fluid flows inside the pipe.

10. The welded pipe according to claim 9, wherein,

the groove extends in a direction intersecting the second end face,

the weld extends along the second end face and intersects the groove.

11. A method for manufacturing a welded pipe, comprising the steps of:

bending a strip-shaped plate-like body in a strip direction with one plate surface as an inner side, wherein the strip-shaped plate-like body is provided with a first step formed by recessing the one plate surface toward the other plate surface side at a first end portion positioned in the strip direction, and the other surface of a second end portion positioned on the opposite side of the first end portion is aligned with a first surface portion positioned on the one plate surface side of the first end portion and positioned on the first end surface side of the first step; and

after the other face of the second end portion is aligned with the first face portion, a weld is formed to weld a second end face of the second end portion to the first face portion of the first end portion.

12. The method for manufacturing a welded pipe according to claim 11, wherein,

in the step of welding the second end surface to the first surface portion provided in the first end portion, the welding portion is formed between the second end surface and the first step, and the welding portion fills the space between the second end surface and the first step.

13. The method for manufacturing a welded pipe according to claim 11 or 12, wherein,

the method also comprises the following steps: before aligning the other face of the second end portion with the first face portion, the first step is formed at the first end portion in the belt direction of the belt-like plate-like body,

in the step of forming the first step, a second step is formed in which the second end portion is recessed toward the second end face side so that the other plate faces the one plate face side,

in the step of aligning the other surface of the second end portion with the first surface portion, a second surface portion is aligned with the first surface portion, wherein the second surface portion is located on the other plate surface side of the second end portion and on the second end surface side of the second step.