Welded pipe manufacturing method and welded pipe manufacturing device

Abstract

A method for manufacturing a welded pipe includes a step for manufacturing a welded pipe. In a step for manufacturing a welded pipe, an electron beam is caused to collide with a first end surface and a second end surface of a tubular body (3) formed by bending a strip-shaped metal plate (2) in a tubular shape in the width direction, and the first end surface and the second end surface are welded to each other, thereby manufacturing the welded pipe. A first end face in the width direction of the strip-shaped metal plate (2) faces a second end face located on the opposite side of the first end face.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a welded pipe and an apparatus for manufacturing a welded pipe. Background Art

[0002] Welded pipes are manufactured by bending a strip metal plate in the width direction into a tube shape and aligning both ends in the width direction and welding them. In such welded pipes, if the welded portion is oxidized, the strength of the welded pipe itself is reduced. Therefore, a method for manufacturing a welded pipe that suppresses oxidation of the welded portion has been developed.

[0003] For example, Patent Document 1 discloses a method for manufacturing a welded pipe in which a shielding gas is supplied into the internal space of a tubular body formed by bending a strip metal plate in the width direction and aligning both ends in the width direction, and the aligned ends are welded.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-271790 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the method for manufacturing a welded pipe described in Patent Document 1, an inert gas is used as a shielding gas. This inert gas is a special gas, so the preparation of the shielding gas and the welding work are not easy.

[0009] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a method for manufacturing a welded pipe and a device for manufacturing a welded pipe that can suppress oxidation of a weld portion without using an inert gas.

[0010] Means for solving problems

[0011] In order to achieve the above-mentioned purpose, the manufacturing method of the welded pipe disclosed in the present invention comprises the following steps: making an electron beam collide with a first end face and a second end face of a tubular body to weld the first end face and the second end face to each other, thereby manufacturing a welded pipe, wherein the tubular body is formed by bending a strip metal plate into a tubular shape in a width direction, and the first end face in the width direction of the strip metal plate is opposite to the second end face located on the opposite side of the first end face.

[0012] Effects of the Invention

[0013] According to the structure of the present disclosure, in the process of manufacturing a welded pipe, the electron beam is made to collide with the first end face and the second end face of the tubular body to weld the first end face and the second end face to each other, thereby manufacturing a welded pipe. As a result, the welded portion where the first end face and the second end face are welded to each other is not easily oxidized. According to the structure of the present disclosure, oxidation of the welded portion can be suppressed without using an inert gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view of the front half of the manufacturing apparatus of the welded pipe in the embodiment of the present disclosure.

[0015] Figure 2 It is a side view of the rear half of the manufacturing apparatus of the welded pipe in the embodiment of the present disclosure.

[0016] Figure 3A This is a plan view showing an example of a belt-shaped metal plate formed by a marking machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0017] Figure 3B This is a plan view showing another example of a belt-shaped metal plate formed by the marking machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0018] Figure 3C This is a plan view showing another example of a belt-shaped metal plate formed by the marking machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0019] Figure 4 It is a cross-sectional view of a forming machine and a welding machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0020] Figure 5A It is a cross-sectional view of a blanking roll included in a forming machine included in a welded pipe manufacturing apparatus according to an embodiment of the present disclosure, and a strip-shaped metal plate formed by the blanking roll.

[0021] Figure 5B It is a cross-sectional view of a blanking roll included in a forming machine included in a welded pipe manufacturing apparatus according to an embodiment of the present disclosure, and a strip-shaped metal plate formed by the blanking roll.

[0022] Figure 5C It is a cross-sectional view of a blanking roll included in a forming machine included in a welded pipe manufacturing apparatus according to an embodiment of the present disclosure, and a strip-shaped metal plate formed by the blanking roll.

[0023] Fig. 6A It is a cross-sectional view of a finishing roll included in a forming machine included in a welded pipe manufacturing apparatus according to an embodiment of the present disclosure, and a strip-shaped metal plate formed by the finishing roll.

[0024] Figure 6BIt is a cross-sectional view of a finishing roll included in a forming machine included in a welded pipe manufacturing apparatus according to an embodiment of the present disclosure, and a strip-shaped metal plate formed by the finishing roll.

[0025] Figure 6C This is a cross-sectional view of a tubular body finally formed by a forming machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0026] Figure 7 It is a cross-sectional view of a modified example of a forming machine and a welding machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0027] Figure 8 It is a cross-sectional view of another modified example of the forming machine and the welding machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0028] Fig. 9 It is a cross-sectional view of still another modified example of the forming machine and the welding machine included in the welded pipe manufacturing apparatus according to the embodiment of the present disclosure.

[0029] Fig.10 It is a cross-sectional view of a modified example of the welded pipe manufacturing apparatus according to the embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, a method for manufacturing a welded pipe and a device for manufacturing a welded pipe according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in the drawings, the same reference numerals are given to the same or equivalent parts. In addition, in the orthogonal coordinate system XYZ shown in the figure, the vertical direction when the upstream and downstream directions of the manufacturing device of the welded pipe are oriented in the horizontal direction is the Z axis, the upstream and downstream directions in the horizontal direction are the X axis, and the direction orthogonal to the Z axis and the X axis is the Y axis.

[0031] (Implementation Method)

[0032] The manufacturing device of the welded pipe of the embodiment is a device for manufacturing a welded pipe from a strip metal plate. The manufacturing device manufactures the welded pipe by welding the joints of a tubular body formed by bending the strip metal plate in the width direction into a tubular shape. In order to suppress oxidation of the welded portion, the welding is performed by causing an electron beam to collide with the joint in a vacuum. The structure of the manufacturing device is described below, taking the case where the welded pipe to be manufactured is a heat transfer pipe used in a heat exchanger as an example. First, referring to Figure 1 , Figure 2 , Figure 3A , Figure 3B as well as Figure 3C , the overall structure of the manufacturing device is described.

[0033] Figure 1 It is a side view of the front half of the welded pipe manufacturing apparatus 1 according to the embodiment. Figure 2 It is a side view of the rear half of the manufacturing apparatus 1 .

[0034] like Figure 1 and Figure 2 As shown, the welded pipe manufacturing apparatus 1 includes an uncoiler 10 , a splicer 11 , an accumulator 12 , marking machines 13 , 14 , a forming machine 15 , a welding machine 16 , a drawing machine 17 , a cutting machine 18 , and a coiling machine 19 .

[0035] A strip-shaped metal plate wound into a coil is supplied to a welded pipe manufacturing apparatus 1. Then, the manufacturing apparatus 1 manufactures a welded pipe from the strip-shaped metal plate. Figure 1 The uncoiler 10 shown unwinds the coiled body formed by winding the strip-shaped metal plate, and pulls out one end side of the strip-shaped metal plate from the coiled body.

[0036] In detail, the uncoiler 10 includes a cylindrical support 111 that holds the coiled body of the strip metal plate from the inside and a driving unit (not shown) that rotates the support 111. The driving unit (not shown) of the uncoiler 10 rotates the support 111 to the side opposite to the winding direction of the coiled body. Thus, the uncoiler 10 pulls out one end of the strip metal plate from the coiled body. The uncoiler 10 supplies one end of the pulled strip metal plate to the splicer 11.

[0037] The connecting machine 11 connects the other end of the strip metal plate to one end of another strip metal plate. Specifically, in the uncoiler 10, although not shown in the figure, when the strip metal plate is completely pulled out from the coil, the next coil is set, and one end side of the strip metal plate is pulled out from the next coil. The connecting machine 11 connects the other end of the strip metal plate of the previous coil on the opposite side of the one end to one end of the strip metal plate pulled out from the next coil.

[0038] The structure thereof will be described. The splicing machine 11 includes a welding machine (not shown). The splicing machine 11 uses the welding machine to weld the other end of the strip metal plate of the previous roll to one end of the strip metal plate of the next roll. The splicing machine is also called a strip joining machine.

[0039] On the other hand, the accumulator 12 stores the strip metal plate pulled out from the coil at a certain length. Specifically, the accumulator 12 includes a roller not shown in the figure. The middle portion of the strip metal plate pulled out from the coil is hung on the roller. Furthermore, in order to prevent the supply of the strip metal plate from being stopped during the welding process using the connector 11, the roller winds the middle portion of the strip metal plate to a certain length that should be supplied within the welding time of the connector 11. Thus, the accumulator 12 retains the strip metal plate at a certain length. After the accumulator 12 winds the middle portion of the strip metal plate to a certain length, one end side portion of the strip metal plate, i.e. Figure 1The +X end portion of the orthogonal coordinate system XYZ shown is sent to the marking machine 13 .

[0040] The marking machines 13 and 14 are for forming grooves on the inner wall of the welded pipe to be manufactured, and more specifically, for forming grooves on the inner wall to improve the heat exchange performance when the welded pipe is used as a heat transfer pipe.

[0041] In detail, although not shown in the figure, the marking machines 13 and 14 include a first roller called a groove roll or simply a G roller having a groove formed on the outer periphery, and a second roller having no irregularities on the outer periphery and having a smooth curved surface. Figure 1 The strip metal plate whose tension is adjusted by the dancer rollers 131 and 132 is sandwiched between the first roller and the second roller. The marking machine 13 passes the strip metal plate between the first roller and the second roller while the first roller and the second roller are pressed against the strip metal plate. Thus, the marking machine 13 forms grooves on the strip metal plate.

[0042] In contrast, the marking machine 14 has a third roller having grooves of a shape different from the grooves of the first roller formed on the outer periphery, and a fourth roller having no unevenness on the outer periphery and a smooth curved surface on the outer periphery. The marking machine 14 uses the third roller and the fourth roller to clamp the strip metal plate having the grooves formed by the marking machine 13 and the tension adjusted by the tension adjustment rollers 132 and 133. In addition, the marking machine 14 presses the third roller and the fourth roller against the strip metal plate. And, the marking machine 14 passes the strip metal plate between the third roller and the fourth roller. Thus, the marking machine 14 forms grooves on the strip metal plate that are different from those in the case of the marking machine 13.

[0043] The marking machines 13 and 14 perform the above-mentioned processing on the belt-shaped metal plate, thereby forming a plurality of grooves having different shapes in the belt-shaped metal plate. Figure 3A , Figure 3B and Figure 3C An example of a belt-shaped metal plate in which such grooves are formed is shown.

[0044] Figure 3A It is a plan view showing an example of the belt-shaped metal plate 2 formed by the marking processing machines 13 and 14 provided in the welded pipe manufacturing apparatus 1. Figure 3B It is a plan view showing another example of the belt-shaped metal plate 2. Figure 3C It is a plan view showing still another example of the belt-shaped metal plate 2 .

[0045] For example, Figure 3AAs shown, the marking machines 13 and 14 form a herringbone groove on the strip metal plate 2 by arranging a plurality of V-shaped grooves along the extending direction of the strip metal plate 2. Alternatively, Figure 3B As shown in FIG. 1 , the marking machines 13 and 14 form a plurality of X-shaped intersecting grooves on the strip metal plate 2. Alternatively, as shown in FIG. Figure 3C As shown in FIG. 1 , the marking machines 13 and 14 form grooves inclined relative to the extending direction of the strip of the strip of metal plate 2 and embossing in a circular shape in a top view on the strip of metal plate 2. The marking machines 13 and 14 form such grooves on the strip of metal plate 2, thereby improving the heat exchange efficiency of the welded pipe when the manufactured welded pipe is used as a heat transfer pipe of a heat exchanger. After forming such grooves on the strip of metal plate 2, the marking machines 13 and 14 move the grooved portion to the right of the strip of metal plate 2. Figure 2 The forming machine 15 and the welding machine 16 are shown as being fed out.

[0046] The detailed structures of the forming machine 15 and the welding machine 16 will be described later. To briefly describe their functions, the forming machine 15 bends the strip metal plate 2 into a tubular shape, such as a round tube shape, in the width direction of the strip, and forms a tubular body in which both ends in the width direction of the strip metal plate 2, that is, the +Y end and the -Y end are aligned. Specifically, the forming machine 15 includes a break down roll and a finpass roll described later. And, the forming machine 15 forms a tubular body in which the +Y end and the -Y end are aligned on the +X end side of the strip metal plate 2 by these rolls.

[0047] On the other hand, the welder 16 welds the joint of the tubular body. The welder 16 is equipped with an electron beam welder described later, and welds the joint of the tubular body by the electron beam welder to produce a welded pipe portion at the +X end side of the strip metal plate 2. Then, the welder 16 conveys the welded pipe portion of the strip metal plate 2 to the drawing machine 17.

[0048] The drawing machine 17 adjusts the outer diameter and inner diameter of the welded pipe portion produced by the welding machine 16. Although not shown in the figure, the drawing machine 17 has a die, and the die is provided with a through hole with a diameter smaller than the outer diameter of the welded pipe produced by the welding machine 16 and the same as the target outer diameter. Then, the drawing machine 17 passes the welded pipe portion of the strip metal plate 2 through the die and pulls the welded pipe portion out of the die. Thus, the drawing machine 17 processes the welded pipe portion of the strip metal plate 2 to have an outer diameter that is the same as the diameter of the through hole of the die. The drawing machine 17 conveys the processed welded pipe portion of the strip metal plate 2 to the Figure 2 The cutter 18 is shown.

[0049] The cutting machine 18 has a Figure 2The cutter 181 moves in the direction from the front to the back, that is, in the Y direction. The cutter 18 moves the cutter 181 to cut the welded pipe portion of the strip metal plate 2 processed by the drawing machine 17 into a desired length. Thus, the cutter 18 produces a welded pipe of a desired length. Then, the cutter 18 delivers the welded pipe formed into a desired length to the coiler 19.

[0050] The coiler 19 has a cylindrical coiling unit 191, and coils the welded pipe cut into a desired length by the cutter 18 around the coiling unit 191. The coiler 19 is thus capable of supplying the produced welded pipe to an external device.

[0051] In addition, the coiled strip metal plate 2 mounted on the uncoiler 10 is, for example, a rolled copper or copper alloy plate. In this case, the tempering may be O material, 1 / 2H material, or 1 / 4H material specified in JIS H3100. In addition, the width of the strip metal plate 2 may be a size corresponding to the outer diameter of the welded pipe before the drawing machine 17 performs diameter reduction. For example, in the case where the outer diameter of the welded pipe before the drawing machine 17 performs diameter reduction is 7 mm, the width of the strip metal plate 2 is 22.5 mm obtained by adding a welding allowance of 0.5 mm to the circumference obtained from the outer diameter. The thickness of the strip metal plate 2 may be 0.05 mm thicker than the thickness of the welded pipe before the drawing machine 17 performs diameter reduction, assuming that the thickness is reduced by 0.05 mm in the marking machine 14.

[0052] Thus, in the welded pipe manufacturing apparatus 1, the unwinder 10 pulls out the strip metal plate 2 wound into a coil, and the marking machines 13 and 14 form grooves in the strip metal plate 2. Furthermore, the forming machine 15 bends the strip metal plate 2 into a tube in the Y direction, and aligns the +Y end and the -Y end of the strip metal plate 2. Then, the welding machine 16 welds the seam formed by aligning the +Y end and the -Y end of the strip metal plate 2, and manufactures a welded pipe.

[0053] At this time, a high-frequency induction welding or TIG (Tungsten Insert Gas) welding device, which is a general welding method, is used as the welding machine 16. If a large amount of oxygen is contained in the atmosphere during welding using this device, oxidation will occur at the formed welded portion. In this case, the strength of the manufactured welded pipe will decrease.

[0054] On the other hand, in order to suppress oxidation of the welded portion, a nozzle is sometimes provided on the high-frequency induction heating welding or TIG welding device, and an inert gas shielding gas such as argon or helium is supplied from the nozzle. However, in this case, since the inert gas is a special gas, it is not easy to prepare the inert gas and to perform operations using the inert gas. In addition, as a result of providing a gas supply device, the device structure becomes complicated and the device settings are cumbersome.

[0055] Therefore, in the welded pipe manufacturing apparatus 1, in order to suppress oxidation of the welded portion, the molding machine 15 and the welding machine 16 are provided with a vacuum chamber, and the molding and welding are performed in the vacuum chamber. Figure 4 , Figure 5A-5C as well as Figure 6A-6C , the structures of the molding machine 15 and the welding machine 16 are explained.

[0056] Figure 4 It is a cross-sectional view of a forming machine 15 and a welding machine 16 included in the welded pipe manufacturing apparatus 1 . Figure 5A-5C It is a cross-sectional view of the blanking rollers 30 - 35 included in the forming machine 15 and the strip-shaped metal plate 2 formed by the blanking rollers 30 - 35 . Fig. 6A and Figure 6B It is a cross-sectional view of the finishing rolls 36 to 39 included in the forming machine 15 and the strip-shaped metal plate 2 formed by the finishing rolls 36 to 39 . Figure 6C 1 is a cross-sectional view of the tubular body 3 finally formed by the forming machine 15 .

[0057] In addition, although Figure 5A-5C , Fig. 6A as well as Figure 6B Although not shown in the figure, the plate surface of the band-shaped metal plate 2 on which the grooves are formed by the marking processing machines 13 and 14 faces upward, that is, the +Z side.

[0058] like Figure 4 As shown, the welded pipe manufacturing apparatus 1 includes vacuum chambers 20-22, blanking rolls 30-35 and finishing rolls 36-39 arranged in the vacuum chamber 21, a vacuum chamber 40 arranged above the vacuum chamber 21, and an electron beam welding machine 41 arranged in the vacuum chamber 40.

[0059] The vacuum chambers 20 to 22, the blanking rolls 30 to 35, and the finishing rolls 36 to 39 are components constituting the forming machine 15. On the other hand, the vacuum chamber 40 and the electron beam welding machine 41 are components constituting the welding machine 16.

[0060] The vacuum chambers 20-22 are rooms provided to maintain a vacuum level that enables electron beam welding. Specifically, the vacuum chambers 20-22 are arranged in the order of vacuum chambers 20, 21, and 22 from the upstream side, i.e., the -X side, of the manufacturing device 1 for the welded pipe. Moreover, the vacuum chambers 20-22 are adjacent to each other in the X direction. Furthermore, conveying rollers 23 and 24 for conveying the strip metal plate 2 as the processing object and the welded pipe portion of the strip metal plate 2 after processing are provided in the vacuum chambers 20 and 22 located on both sides of the X direction. In addition, the blanking rollers 30-35 and the finishing rollers 36-39 for forming the tubular body 3 as the welding object from the strip metal plate 2 as the processing object are accommodated in the vacuum chamber 21 located in the center of the X direction. In addition, the vacuum chamber 40 that accommodates the electron beam welding machine 41 is connected to the vacuum chamber 21. Thus, forming and welding as the manufacturing process of the welded pipe can be performed inside the vacuum chamber 21.

[0061] In addition, since the vacuum chamber 21 performs forming and welding of the strip-shaped metal plate 2 to be processed, the volume thereof can be larger than that of the vacuum chambers 20 and 22 .

[0062] In order to increase the vacuum degree in the vacuum chamber 21 located at the center in the X direction among the vacuum chambers 20 to 22 , although not shown, the vacuum chamber 21 is evacuated by a vacuum pump that achieves a higher ultimate vacuum degree than the vacuum pumps evacuating the vacuum chambers 20 and 22 .

[0063] In detail, an exhaust port not shown in the figure is formed in each of the vacuum chambers 20-22, and vacuum pumps not shown in the figure are connected to these exhaust ports. Among these vacuum pumps not shown in the figure, the vacuum pump connected to the exhaust ports of the vacuum chambers 20 and 22 is for low vacuum. For example, the vacuum pump for low vacuum is a water flow pump, a pump based on mechanical force such as a reciprocating, rotary, or centrifugal pump. In contrast, the vacuum pump connected to the exhaust port of the vacuum chamber 21 is for medium vacuum, such as a mechanical booster pump or a turbomolecular pump. In the vacuum chambers 20-22, by connecting such a vacuum pump, a structure is achieved in which the vacuum chamber 21 with a high vacuum degree is sandwiched from both sides of the vacuum chambers 20 and 22 with a low vacuum degree in the X direction. For example, a structure is achieved in which the vacuum chamber 21 with a vacuum degree of 2.0 to 6.0 Pa is sandwiched by the vacuum chambers 20 and 22 with a vacuum degree of 50 to 800 Pa.

[0064] Among them, medium vacuum refers to the vacuum degree of a vacuum zone that meets the vacuum specified in the Japanese Industrial Standard, and means that the vacuum degree is 0.1 to 100 Pa. Low vacuum refers to the vacuum degree of another vacuum zone that meets the vacuum specified in the standard, and means that the vacuum degree is 100,000 to 100 Pa. Moreover, the vacuum mentioned in this specification refers to low vacuum or vacuum with a higher vacuum degree than low vacuum. In addition, the vacuum chambers 20 and 22 are the same low vacuum, but the same vacuum degree mentioned here refers to the same zone in the above-mentioned vacuum zone.

[0065] Furthermore, in the vacuum chamber 20, in order to supply and discharge the strip metal plate 2 as the processing object, Figure 4 As shown, an inlet 201 and an outlet 202 are provided. The YZ cross-sectional shape of these inlet 201 and outlet 202 is larger than the YZ cross-sectional shape of the strip metal plate 2 to the extent that there is a gap. Moreover, the strip metal plate 2 passes through the inlet 201 and outlet 202. As a result, between the inner walls of the inlet 201 and outlet 202 and the strip metal plate 2, there are formed minute gaps 205 and 206 to the extent that the strip metal plate 2 can slide. In addition, the inflow of air from the outside into the vacuum chamber 20 is small, and as a result, the decrease in the vacuum degree of the vacuum chamber 20 is suppressed.

[0066] Similarly, in the vacuum chamber 21, in order to supply the strip metal plate 2 as the processing object, an inlet 211 of the same shape and size as the outlet 202 of the vacuum chamber 20 is provided. In addition, the inlet 211 is adjacent to and continuous with the outlet 202 in the X direction. As a result, the inlet 211 is connected to the vacuum chamber 20. In addition, the strip metal plate 2 passes through the inlet 211. As a result, a small gap 215 is formed between the inner wall of the inlet 211 and the strip metal plate 2 to a degree that allows the strip metal plate 2 to slide, and the reduction of the vacuum degree of the vacuum chamber 21 is suppressed. In particular, since the inlet 211 is connected to the vacuum chamber 20 with a low vacuum in the -X direction, the vacuum degree of the vacuum chamber 21 is not easily reduced compared to the case where the inlet 211 is directly connected to the external space.

[0067] In addition, in the vacuum chamber 21, in order to discharge the welded pipe portion 4 of the strip metal plate 2 formed and welded in the vacuum chamber 21, an outlet 212 is provided whose YZ cross-sectional shape is larger than the YZ cross-sectional shape of the welded pipe portion 4 to the extent that there is a clearance. Moreover, the welded pipe portion 4 formed on one end side of the strip metal plate 2, that is, formed on the +X end side, passes through the outlet 212. As a result, a small gap 216 is formed between the inner wall of the outlet 212 and the welded pipe portion 4 to the extent that the welded pipe portion 4 can slide, and the reduction of the vacuum degree of the vacuum chamber 21 is suppressed. In addition, the outlet 212 is connected to the vacuum chamber 22 of low vacuum via the inlet 221 described later. As a result, the vacuum degree of the vacuum chamber 21 is suppressed from being sharply reduced due to the outlet 212.

[0068] On the other hand, in the vacuum chamber 22, in order to allow the welding pipe part 4 to pass through, an inlet 221 and an outlet 222 of the same shape and size as the outlet 212 of the vacuum chamber 21 are provided. Moreover, the welding pipe part 4 that has passed through the outlet 212 of the vacuum chamber 21 passes through the inlet 221 and the outlet 222. As a result, small gaps 225 and 226 are formed between the inner walls of the inlet 221 and the outlet 222 and the welding pipe part 4 to the extent that the welding pipe part 4 can slide. In addition, the inflow of air from the outside to the vacuum chamber 22 is small, and the reduction of the vacuum degree of the vacuum chamber 22 is suppressed. Moreover, the inlet 221 and the outlet 212 of the vacuum chamber 21 are adjacent and continuous in the X direction. As a result, the vacuum degree of the adjacent vacuum chamber 21 is not easily reduced compared with the case where it is directly connected to the external space.

[0069] In addition, the welding pipe part 4 has a space in the center of the pipe. Therefore, there is a possibility that the air outside the device flows into the vacuum chambers 21 and 22 through the inside of the welding pipe part 4. Therefore, before the manufacturing device 1 of the welding pipe is operated to manufacture the welding pipe, a special setting is made to make the strip metal plate 2 as the processing object pass through the vacuum chambers 20-22. In this special setting, the welding pipe part 4 is made on the +X end side of the strip metal plate 2, and the +X end of the welding pipe part 4 is sealed. For example, in the area of ​​the vacuum chamber 21 that is closer to the +X side than the part where the electron beam collides with the tubular body 3 described later, or in the vacuum chamber 22, a device for crushing the end of the pipe is set, and the device crushes the +X end of the welding pipe part 4. As a result, it is possible to prevent the vacuum degree of the vacuum chambers 21 and 22 from being reduced through the internal space of the welding pipe part 4. In addition, the crushed +X end of the welding pipe part 4 cannot be used as a welding pipe. Therefore, the +X end can be removed by the above-mentioned cutting machine 18.

[0070] By providing such inlets 201, 211, 221 and outlets 202, 212, 222 in the vacuum chambers 20-22, the vacuum degree is maintained. In addition, the vacuum degree of the vacuum chamber 21 located in the center in the X direction is higher than the vacuum degrees of the vacuum chambers 20 and 22 located on both sides of the vacuum chamber 21 in the X direction, and the vacuum degree in the vacuum chamber 21 is maintained to be a vacuum degree that can be electron beam welded. In addition, in order to form the strip metal plate 2 into a weldable shape in the vacuum chamber 21, the blanking rolls 30-35 and the finishing rolls 36-39 are provided in the vacuum chamber 21 as described above.

[0071] like Figure 5A-5C As shown, the blanking rollers 30-35 are arranged at the top or bottom, and the strip metal plate 2 is roughly formed into a cross-sectional arc shape by passing the strip metal plate 2 therebetween.

[0072] In detail, the blank opening rollers 30-35 are Figure 4The upstream side, i.e., -X side, is arranged in the order of the blank opening rollers 30 and 31, 32 and 33, 34 and 35. Figure 5A-5C As shown, the opening roller 30 having a convex portion 301 protruding downward, that is, protruding toward the -Z side, and the opening roller 31 having a concave portion 311 recessed toward the -Z side are arranged in the Z direction to form a pair. In addition, the opening roller 32 having a convex portion 321 protruding toward the -Z side and the opening roller 33 having a concave portion 331 recessed toward the -Z side are arranged in the Z direction to form a pair. Moreover, the opening roller 34 having a convex portion 341 protruding toward the -Z side and the opening roller 35 having a concave portion 351 recessed toward the -Z side are arranged in the Z direction to form a pair.

[0073] Furthermore, in the blank opening rollers 30, 32, 34, the heights of the convex parts 301, 321, 341 in the Z direction become higher in the order of the convex parts 301, 321, 341, in other words, in the order of arrangement toward the downstream side, that is, the +X side. On the other hand, the widths of the convex parts 301, 321, 341 in the Y direction become narrower in the same order. Moreover, the YZ cross-sectional shapes of the front ends of the convex parts 301, 321, 341 are more rounded in the same order.

[0074] On the other hand, in the blank opening rollers 31, 33, 35, the depth of the recesses 311, 331, 351 in the Z direction becomes deeper in the order in which the blank opening rollers 31, 33, 35 are arranged toward the +X side. On the other hand, the width of the recesses 311, 331, 351 in the Y direction becomes narrower in the same order. Moreover, the YZ cross-sectional shape of the recesses 311, 331, 351 is further curved in the same order to approach an arc shape.

[0075] The opening rolls 30-35 have such a shape, so that the strip metal plate 2 is further bent toward the +X side. Figure 5A-5C The shape of the YZ cross-sectional circular arc shown. In addition, the plate surface of the belt-shaped metal plate 2 where the grooves are formed faces the inside of the YZ cross-sectional circular arc.

[0076] On the other hand, Fig. 6A and Figure 6B As shown, the finishing rolls 36-39 are arranged in the Z direction to form a pair in the same manner as the blanking rolls 30-35, but unlike the blanking rolls 30-35, the strip metal plate 2 is finished and formed into a YZ cross-sectional circular shape by passing the strip metal plate 2 between these pairs of rolls.

[0077] In detail, Figure 4 As shown, the finishing rollers 36-39 are arranged in the order of finishing rollers 36 and 37, 38 and 39 from the -X side. Fig. 6A as well as Figure 6BAs shown, a finishing roll 36 having a fin portion 361 protruding in a triangular cross-section toward the -Z side formed in a concave portion having a cross-section concave in an arc shape toward the +Z side and a finishing roll 37 having a concave portion having a cross-section concave in an arc shape toward the -Z side are arranged in the Z direction to form a pair. In addition, a finishing roll 38 having a fin portion 381 protruding in a triangular cross-section toward the -Z side formed in a concave portion having a cross-section concave in an arc shape toward the +Z side and a finishing roll 39 having a concave portion having a cross-section concave in an arc shape toward the -Z side are arranged in the Z direction to form a pair.

[0078] Furthermore, in the finishing rolls 36 and 38, the width in the Y direction and the height in the Z direction of the fin portions 361 and 381 decrease in the order of the fin portions 361 and 381, in other words, in the order of arrangement toward the downstream side, i.e., the +X side. Furthermore, the concave portions of the finishing rolls 36 and 38 and the concave portions of the finishing rolls 37 and 39 are opposed in the Z direction to form a space having a circular cross-section.

[0079] The finishing rollers 36-39 have such a shape, and the strip metal plate 2 is finished and formed into a YZ cross-sectional circular shape with the +Y end and -Y end of the strip metal plate 2 approaching each other as it moves toward the +X side. In addition, the finishing rollers 36-39 finally form a tubular body 3 having a seam 5, which is not Figure 6C The +Y end and -Y end of the strip metal plate 2 shown by the dotted line are in a V-shaped opposite shape, that is, the two ends of the strip metal plate 2 are not in a V-shaped opposite shape, but the two ends of the strip metal plate 2 are in a V-shaped opposite shape. Figure 6C The shape is relative to the state shown by the solid line. In addition, in the formed tubular body 3, the plate surface of the strip metal plate 2 where the groove is formed faces inward, and as a result, the groove is provided on the inner wall.

[0080] return Figure 4 A vacuum chamber 40 accommodating an electron beam welding machine 41 is provided above the finishing rollers 38 and 39 of the vacuum chamber 21 in order to weld the seam 5 of the tubular body 3 formed by the finishing rollers 36 to 39 .

[0081] A communication hole 42 is formed on the lower surface of the vacuum chamber 40 and is continuous with the through hole 25 on the upper surface of the vacuum chamber 21. An electron beam welding machine 41 is arranged above the communication hole 42 in the vacuum chamber 40.

[0082] Although not shown, the electron beam welding machine 41 includes a cathode portion that generates an electron beam when a voltage is applied, an anode portion that accelerates the electron beam, and an electron lens portion that converges or deflects the electron beam. The electron beam welding machine 41 emits the electron beam generated by the cathode portion toward the above-mentioned connecting hole 42 and through hole 25, and causes the electron beam to collide with the joint 5 of the tubular body 3 of the vacuum chamber 21. Thus, the electron beam welding machine 41 welds the joint 5 of the tubular body 3 to produce the welded pipe portion 4.

[0083] At this time, the interior of the vacuum chamber 21 is in a vacuum state, so there is almost no oxygen. As a result, in the welded pipe manufacturing apparatus 1, the welded portion formed at the joint 5 of the tubular body 3 that collides with the electron beam is not easily oxidized. As a result, the strength of the manufactured welded pipe is high.

[0084] In addition, the two ends of the above-mentioned strip metal plate 2, in other words, the +Y end and the -Y end of the strip metal plate 2 are an example of the first end face and the second end face in the width direction of the strip metal plate 2 mentioned in the present disclosure. In addition, the part formed or welded on the +X side of the strip metal plate 2 is an example of the first part located on the one end side mentioned in the present disclosure.

[0085] In addition, the above-mentioned vacuum chamber 21, the inlet 211 and the outlet 212 of the vacuum chamber 21 are examples of the first vacuum chamber, the first inlet and the first outlet mentioned in the present disclosure. In addition, the vacuum chamber 20, the inlet 201 and the outlet 202 of the vacuum chamber 20 are examples of the second vacuum chamber, the second inlet and the second outlet mentioned in the present disclosure. The vacuum chamber 22, the inlet 221 and the outlet 222 of the vacuum chamber 22 are examples of the third vacuum chamber, the third inlet and the third outlet mentioned in the present disclosure. Furthermore, the gaps 205, 206, and 215 are examples of the first gaps mentioned in the present disclosure. The gaps 216, 225, and 226 are examples of the second gaps mentioned in the present disclosure.

[0086] The above-mentioned conveying rollers 23 and 24 are an example of the conveying mechanism mentioned in the present disclosure. The process of conveying the strip metal plate 2 by the conveying rollers 23 and 24 is an example of the process of conveying the strip metal plate into the first vacuum chamber or the process of conveying the welded pipe from the first vacuum chamber mentioned in the present disclosure. In addition, the blanking rollers 30-35 and the finishing rollers 36-39 are an example of the forming rollers mentioned in the present disclosure.

[0087] Furthermore, the process of forming grooves on the strip metal plate 2 by the above-mentioned marking machines 13 and 14 is an example of the process of forming grooves in the present disclosure. The first roller, the second roller, the third roller and the fourth roller provided by the marking machines 13 and 14 are an example of the groove forming rollers in the present disclosure. In addition, the forming of the tubular body 3 by the above-mentioned blanking rollers 30-35 and the finishing rollers 36-39 is an example of the process of forming the tubular body in the present disclosure. In addition, the welding of the joint 5 of the tubular body 3 by the electron beam welding machine 41, that is, the welding process is an example of the process of making a welded pipe in the present disclosure.

[0088] In addition, various conditions of the electron beam welding machine 41 are determined by the size and material of the welded pipe to be manufactured. For example, the rated output may be 6 kW, the acceleration voltage may be 40 kV, the electron beam current may be 5 to 150 mA, and the cathode may be in the shape of a W rod.

[0089] As described above, in the welded pipe manufacturing apparatus 1 of the embodiment, the electron beam welding machine 41 performs welding by causing electron beams to collide in a vacuum. Therefore, the manufacturing apparatus 1 can suppress oxidation of the formed welded portion. As a result, the strength of the welded portion is high, and the strength of the manufactured welded pipe is high.

[0090] In addition, in the welded pipe manufacturing apparatus 1, the electron beam welding machine 41 performs welding in a vacuum, so there is no need to use an inert gas. As a result, there is no need to prepare a special gas, so the preparation and operation of manufacturing the welded pipe are easy.

[0091] In the manufacturing apparatus 1 of the welded pipe, the vacuum chamber 20 having a lower vacuum degree than the vacuum chamber 21 is adjacent to the inlet 211 side of the vacuum chamber 21 where welding is performed. Then, the portion on the one end side of the strip-shaped metal plate 2 to be processed is fed into the vacuum chamber 21 from the inlet 211 after passing through the vacuum chamber 20. Therefore, the vacuum degree of the vacuum chamber 21 is not easily reduced, and it is easy to maintain a vacuum degree that allows electron beam welding.

[0092] Similarly, in the welded pipe manufacturing apparatus 1, the vacuum chamber 22 having a lower vacuum degree than the vacuum chamber 21 is adjacent to the outlet 212 side of the vacuum chamber 21. Then, the welded pipe portion 4 of the strip metal plate 2 is sent to the outside after passing through the vacuum chamber 22 from the outlet 212. Therefore, the vacuum degree of the vacuum chamber 21 is not easily reduced, and it is easy to maintain a vacuum degree that allows electron beam welding.

[0093] As mentioned above, although the manufacturing method of a welded pipe and the manufacturing apparatus 1 of a welded pipe according to the embodiment of the present disclosure have been described, the manufacturing method of a welded pipe and the manufacturing apparatus 1 of a welded pipe are not limited thereto.

[0094] (Variant 1)

[0095] In the first embodiment, only the small gaps 215 and 216 are provided at the inlet 211 and the outlet 212 of the vacuum chamber 21. However, the vacuum chamber 21 is not limited thereto. The inlet 211 and the outlet 212 of the vacuum chamber 21 may be provided with seals.

[0096] Figure 7 It is a cross-sectional view of a modified example of a forming machine and a welding machine included in the welded pipe manufacturing apparatus 1 .

[0097] like Figure 7 As shown, a seal 50 along the inner wall surface may be provided at the inlet 211 of the vacuum chamber 21. In addition, a seal 51 along the inner wall surface may be provided at the outlet 212 of the vacuum chamber 21. This is because, if such a method is adopted, it is easy to improve the airtightness of the vacuum chamber 21 and to maintain the vacuum degree of the vacuum chamber 21. In addition, as a result, oxidation of the welded portion can be further suppressed.

[0098] In this case, although not shown, the seals 50 and 51 may be frame-shaped or O-ring-shaped. Furthermore, in order to allow the strip metal plate 2 or the welded pipe portion 4 to enter and exit the vacuum chamber 21, the seals 50 and 51 may be formed of a low-friction material, such as polytetrafluoroethylene of a fluororesin. In addition, the seals 50 and 51 may be provided at the inlet 201 and the outlet 202 of the vacuum chamber 20 and the inlet 221 and the outlet 222 of the vacuum chamber 22 in the same arrangement as in the case of the vacuum chamber 21. In this case, the seals 50 and 51 may be provided in the vacuum chamber 21 having a high degree of vacuum, in preference to the vacuum chambers 20 and 22.

[0099] (Variant 2)

[0100] In the first embodiment, the end of the welded pipe portion 4 formed on one end of the strip metal plate 2 is sealed in advance to prevent air outside the device from flowing into the vacuum chambers 21 and 22. In this state, the welded pipe manufacturing device 1 is operated to manufacture the welded pipe. However, the method of preventing air from flowing into the vacuum chambers 21 and 22 is not limited to this. A plug may be formed on the welded pipe portion 4 of the strip metal plate 2.

[0101] Figure 8 It is a cross-sectional view of another modified example of the forming machine and the welding machine included in the welded pipe manufacturing apparatus 1 .

[0102] like Figure 8 As shown, a plug 60 may be provided in the internal space of the -X end portion of the welded pipe portion 4. Specifically, the strip metal plate 2 may be formed into a tubular body 3, and a cylindrical micro plug 60 may be provided in the internal space of the portion just welded by the electron beam welder 41. This is because, if this is the case, it is possible to prevent air from flowing in through the internal space of the welded pipe portion 4 of the strip metal plate 2.

[0103] In this case, the plug 60 may be supported by a support rod 61, one end of which is fixed to the inner wall of the vacuum chamber 21, and the other end of which is bent parallel to the X direction and inserted from the -X side into the inner space of the welded pipe portion 4. In addition, the plug 60 may have an outer diameter that allows for gradual insertion into the welded pipe portion 4. In addition, the plug 60 may be formed of a low-friction material similar to the seals 50 and 51 of Modification 1.

[0104] (Variant 3)

[0105] In the embodiment, the measuring device is not provided in the vacuum chambers 20 to 22, but the measuring device may be provided in the vacuum chambers 20 to 22. Furthermore, the welded pipe manufacturing apparatus 1 may operate based on the measurement result of the measuring device.

[0106] For example, the manufacturing device 1 of the welded pipe may also include a vacuum gauge that is installed in the vacuum chamber 21 and measures the vacuum degree in the vacuum chamber 21. Here, the vacuum gauge is, for example, a U-tube pressure gauge or a diaphragm vacuum gauge. In the manufacturing device 1 of the welded pipe, if there is a welding defect in the welded pipe portion 4 of the tubular body 3 that is welded in the vacuum chamber 21, if the portion where the welding defect exists protrudes out of the vacuum chamber 22 through the vacuum chamber 22, air will flow into the inside of the welded pipe portion 4 from the portion where the welding defect exists. In this case, the inflowing air enters the vacuum chamber 21 from the unwelded joint 5 of the tubular body 3, thereby reducing the vacuum degree of the vacuum chamber 21 and further oxidizing the welded portion. Therefore, a vacuum gauge may be installed in the vacuum chamber 21, and the control device described later provided in the manufacturing device 1 of the welded pipe may determine whether the above-mentioned welding defect exists based on the pressure data measured by the vacuum gauge. Moreover, if the control device determines that there is a welding defect, the manufacturing device 1 may stop manufacturing the welded pipe. In addition, when the control device determines that there is a welding defect, the welding pipe portion 4 extending outside the vacuum chamber 22 at this time may be set as defective, and the portion after the welding pipe portion 4 located inside the vacuum chamber 21 where the vacuum degree is reduced may be set as defective. In addition, in determining whether there is a welding defect, when the pressure measured by the vacuum gauge is a gauge pressure, the gauge pressure may be converted into an absolute pressure. And, when the pressure value measured by the vacuum gauge is greater than a threshold value, it may be determined that there is a welding defect.

[0107] Furthermore, although the example in which the vacuum gauge is provided in the vacuum chamber 21 has been described, the vacuum gauge only needs to be provided in at least one of the vacuum chambers 20 to 22 .

[0108] (Variant 4)

[0109] The vacuum gauge may be replaced by another vacuum measuring device. For example, the vacuum gauge may be replaced by an optical leak detector.

[0110] Fig. 9 It is a cross-sectional view of still another modified example of the forming machine and the welding machine included in the welded pipe manufacturing apparatus 1 .

[0111] like Fig. 9As shown, the manufacturing device 1 of the welded pipe may also include an optical leak detector 70 that is disposed in the vacuum chamber 22 and measures the vacuum degree in the vacuum chamber 22. Here, the optical leak detector 70 is a device that includes: two electrodes that are disposed in a measurement environment, in this case, in a housing that communicates with the vacuum chamber 22, and that emit electrons when a potential difference is provided; and an optical measuring device that measures the spectral intensity of light emitted when the emitted electrons collide with atoms and molecules of the gas in the housing, and calculates the partial pressure of the gas based on the spectral intensity measured by the optical measuring device. In addition, the two electrodes and the optical measuring device may be directly disposed in the vacuum chamber 22 instead of in the housing.

[0112] When the outside gas flows into the vacuum chamber 22, the outside gas contains a large amount of nitrogen, and as a result, the optical measuring device provided in the optical leak detector 70 measures the spectral intensity of the purple light. Alternatively, the outside gas also contains oxygen, so the optical measuring device measures the spectral intensity of the lavender light according to its concentration. Based on such a background, when the outside gas flows into the vacuum chamber 22, the optical leak detector 70 can obtain the pressure in the housing based on the measured spectral intensity, thereby obtaining the pressure in the vacuum chamber 22. In addition, the control device 80 can also determine the presence or absence of the above-mentioned welding defect based on the pressure obtained by the optical leak detector 70.

[0113] The optical leak detector 70 may be installed in the vacuum chamber 20 or 22 instead of the vacuum chamber 21. If the optical leak detector 70 is installed in the vacuum chamber 21, two electrodes of the optical leak detector 70 may interfere with electron beam welding, and welding may not be performed at an appropriate location.

[0114] The control device 80 may include a CPU (Central Processing Unit) 81 and a memory 82 , and the CPU 81 may read and execute a determination program stored in the memory 82 to perform the determination process of whether or not the welding defect is present.

[0115] In addition, in the embodiment, the manufacturing device 1 of the welded pipe has three vacuum chambers 20-22. However, the manufacturing device 1 of the welded pipe is not limited thereto. In the manufacturing device 1 of the welded pipe, the vacuum chamber 20-22 is a device for storing a tubular body, which is formed by bending the strip metal plate 2 into a tubular shape along the width direction, and the first end face in the width direction of the strip metal plate 2 is opposite to the second end face located on the opposite side of the first end face. And, inside the vacuum chamber 20-22, the electron beam is made to collide with the first end face and the second end face of the tubular body to weld the first end face and the second end face to each other, so that the electron beam welding machine 41 can make the welded pipe. Therefore, as long as these conditions are met, the number of vacuum chambers 20-22 is arbitrary. For example, the manufacturing device 1 of the welded pipe can also have only one vacuum chamber 21. This is because even in such a way, the oxidation of the welded portion can be suppressed.

[0116] In addition, in the embodiment, the forming machine 15 and the welding machine 16 are stored in the vacuum chamber 20-22. However, the equipment stored in the vacuum chamber 20-22 is not limited thereto. As long as the above conditions are met, the electron beam welding machine 41 can make a welded pipe, so other equipment for processing the strip metal plate 2 can also be stored in the vacuum chamber 20-22.

[0117] Fig.10 It is a cross-sectional view of a modified example of the welded pipe manufacturing apparatus 1 according to the embodiment.

[0118] like Fig.10 As shown, the marking machines 13, 14 and the dancer rollers 131-133 described in the embodiment can also be accommodated in the vacuum chamber 21. As a result, grooves can be formed on the strip metal plate 2 in the vacuum chamber 21. This is because, if this is the case, the strip metal plate 2 having a flat plate surface without grooves is introduced from the entrance 211 of the vacuum chamber 21, so the gap 215 of the entrance 211 can be reduced, and the vacuum degree of the vacuum chamber 21 can be further reduced. In addition, the vacuum degree of the vacuum chamber 21 is easily maintained.

[0119] In the embodiment, the manufacturing apparatus 1 of the welded pipe includes the reservoir 12. However, the manufacturing apparatus 1 of the welded pipe is not limited thereto. In the manufacturing apparatus 1 of the welded pipe, the reservoir 12 may be an arbitrary structure. For example, in the case where the production efficiency may also be reduced, the manufacturing apparatus 1 of the welded pipe may not include the reservoir 12.

[0120] In the embodiment, the manufacturing device 1 of the welded pipe includes the marking machines 13 and 14. However, the manufacturing device 1 of the welded pipe is not limited thereto. In the manufacturing device 1 of the welded pipe, the marking machines 13 and 14 are of any structure. For example, when manufacturing a welded pipe without a groove, the manufacturing device 1 of the welded pipe may not include the marking machines 13 and 14. In addition, when manufacturing a welded pipe with a groove, the manufacturing device 1 of the welded pipe only needs to include at least one marking machine 13 and 14 in order to form the groove.

[0121] In the embodiment, the manufacturing apparatus 1 of the welded pipe does not include any machine or device after the coiler 19. However, the manufacturing apparatus 1 of the welded pipe is not limited thereto. The manufacturing apparatus 1 of the welded pipe may include an annealing device after the coiler 19 in order to suppress the welded pipe produced from being broken during bending or expansion.

[0122] In the embodiment, the welded pipe manufacturing device 1 is described by taking the case where the welded pipe to be manufactured is a heat transfer pipe for a heat exchanger as an example. However, the welded pipe to be manufactured is not limited thereto. The welded pipe manufacturing method and welded pipe manufacturing device 1 of the embodiment of the present disclosure can be applied to all welded pipes that need to suppress oxidation of the welded portion.

[0123] As described above, the manufacturing method of a welded pipe and the manufacturing apparatus 1 of a welded pipe are not limited to the above-mentioned embodiment, and various modifications and substitutions can be added. Hereinafter, various aspects of the present disclosure will be described as supplementary notes.

[0124] (Note 1)

[0125] A method for manufacturing a welded pipe comprises the following steps: causing an electron beam to collide with a first end face and a second end face of a tubular body to weld the first end face and the second end face to each other, thereby manufacturing a welded pipe, wherein the tubular body is formed by bending a strip metal plate into a tubular shape in a width direction, and the first end face in the width direction of the strip metal plate is opposite to the second end face located on the opposite side of the first end face.

[0126] (Note 2)

[0127] The method for manufacturing a welded pipe according to Supplement 1, wherein:

[0128] The method for manufacturing a welded pipe further comprises the steps of: bending the strip metal plate into a tubular shape in the width direction in a vacuum space, thereby forming the tubular body in a shape in which the first end face and the second end face face each other;

[0129] In the step of manufacturing the welded pipe, the electron beam is caused to collide with the first end face and the second end face of the tubular body in the vacuum space to weld the first end face and the second end face to each other.

[0130] (Note 3)

[0131] The method for manufacturing a welded pipe according to Supplementary Note 2, wherein:

[0132] The method for manufacturing a welded pipe further comprises the steps of: feeding the strip-shaped metal plate from one end side in the direction in which the strip extends into a first vacuum chamber having the vacuum space;

[0133] In the step of forming the tubular body, a first portion of the strip-shaped metal plate located at the one end side is bent into a tubular shape along the width direction inside the first vacuum chamber, thereby forming the tubular body at the first portion.

[0134] In the step of manufacturing the welded pipe, the electron beam is caused to collide with the first end face and the second end face of the tubular body formed in the first portion inside the first vacuum chamber to weld the first end face and the second end face to each other.

[0135] (Note 4)

[0136] The method for manufacturing a welded pipe according to any one of Supplementary Notes 1 to 3, wherein:

[0137] The method for manufacturing the welded pipe further comprises the steps of: forming grooves on the plate surface of the strip metal plate in a vacuum space;

[0138] In the process of manufacturing the welded pipe, in the vacuum space, the electron beam is caused to collide with the first end face and the second end face of the tubular body formed by bending the strip metal plate with the plate surface having the groove facing inward, thereby welding the first end face and the second end face to each other.

[0139] (Note 5)

[0140] The method for manufacturing a welded pipe according to Supplementary Note 4, wherein:

[0141] The method for manufacturing a welded pipe further comprises the steps of: feeding the strip-shaped metal plate from one end side in the direction in which the strip extends into a first vacuum chamber having the vacuum space;

[0142] In the step of forming the groove, the groove is formed on a plate surface of a first portion of the band-shaped metal plate located on the one end side inside the first vacuum chamber.

[0143] In the process of making the welded pipe, inside the first vacuum chamber, the electron beam is made to collide with the first end face and the second end face of the tubular body formed in the first portion by bending the first portion of the strip metal plate with the plate surface having the groove facing inward, and the first end face and the second end face are welded to each other.

[0144] (Note 6)

[0145] The method for manufacturing a welded pipe according to Supplement 3 or 5, wherein:

[0146] The method for manufacturing a welded pipe further comprises the steps of: sending out the welded pipe produced in the first portion from the first vacuum chamber,

[0147] A second vacuum chamber adjacent to the first vacuum chamber and having a lower vacuum degree than the first vacuum chamber is provided on the side of the first vacuum chamber at the one end side where the strip-shaped metal plate is fed.

[0148] On the side of the first vacuum chamber from which the welding pipe is sent out, a third vacuum chamber is provided adjacent to the first vacuum chamber and has a lower vacuum degree than the first vacuum chamber.

[0149] In the step of feeding the strip-shaped metal plate into the first vacuum chamber, the strip-shaped metal plate is fed into the first vacuum chamber via the second vacuum chamber.

[0150] In the step of sending out the welded tube from the first vacuum chamber, the welded tube is sent out from the first vacuum chamber to the outside via the third vacuum chamber.

[0151] (Note 7)

[0152] The method for manufacturing a welded pipe according to any one of Supplementary Notes 3, 5, and 6, wherein:

[0153] In the process of manufacturing the welded pipe, one end of the welded pipe is closed, and the internal space of the welded pipe is the same vacuum as the interior of the first vacuum chamber.

[0154] (Note 8)

[0155] The method for manufacturing a welded pipe according to any one of Supplementary Notes 1 to 7, wherein:

[0156] The step of manufacturing the welded pipe includes the step of measuring the degree of vacuum of a space where the electron beam collides with the first end surface and the second end surface using a vacuum gauge, and determining the presence or absence of a welding defect based on the measured value of the degree of vacuum.

[0157] (Note 9)

[0158] The method for manufacturing a welded pipe according to any one of Supplementary Notes 1 to 7, wherein:

[0159] The process of making the welded pipe includes the following steps: causing electrons to collide with gas located in another space to emit light, the other space being connected to the space where the electron beam collides with the first end face and the second end face, measuring the spectrum of the light to determine the pressure of the gas, thereby determining the vacuum degree of the space where the electron beam collides, and judging whether there are welding defects based on the determined vacuum degree.

[0160] (Note 10)

[0161] A manufacturing device for a welded pipe, comprising:

[0162] a first vacuum chamber that accommodates a tubular body formed by bending a strip-shaped metal plate in a width direction into a tubular shape, wherein a first end face in the width direction of the strip-shaped metal plate faces a second end face located on an opposite side to the first end face; and

[0163] An electron beam welding machine causes an electron beam to collide with the first end face and the second end face of the tubular body inside the first vacuum chamber to weld the first end face and the second end face to each other, thereby manufacturing a welded pipe.

[0164] (Note 11)

[0165] The manufacturing apparatus of the welded pipe according to Supplementary Note 10, wherein:

[0166] The welded pipe manufacturing device further includes a conveying mechanism that conveys the strip-shaped metal plate into the first vacuum chamber from one end side in the direction in which the strip extends.

[0167] The first vacuum chamber has:

[0168] a first inlet into which the strip-shaped metal plate is fed from the one end side; and

[0169] The first outlet is formed by feeding the strip metal plate from the one end side into the first inlet by the conveying mechanism, and the welded pipe produced at the portion located at the one end side is fed out of the first outlet, wherein the welded pipe is formed by welding the second end face of the tubular body to the first end face by the electron beam welding machine.

[0170] A forming roller is accommodated in the internal space of the first vacuum chamber. The forming roller bends the portion of the strip metal plate located on the one end side, which is fed into the first vacuum chamber from the first inlet by the conveying mechanism, into a tubular shape in the width direction, and forms a tubular body in the portion located on the one end side in a shape in which the first end face and the second end face are opposite to each other.

[0171] (Note 12)

[0172] The manufacturing apparatus of a welded pipe according to Supplementary Note 11, wherein:

[0173] A groove forming roller is accommodated in the internal space of the first vacuum chamber, and the groove forming roller forms grooves on the plate surface of the strip-shaped metal plate fed into the first vacuum chamber from the first inlet by the feeding mechanism.

[0174] The forming roller forms the tubular body by bending the first portion of the strip-shaped metal plate in a state where the plate surface on which the groove is formed faces inward.

[0175] (Note 13)

[0176] The manufacturing apparatus of a welded pipe according to Supplementary Note 11 or 12, wherein:

[0177] The manufacturing device of the welded pipe further comprises:

[0178] a second vacuum chamber, which is adjacent to the first vacuum chamber on the side where the first inlet of the first vacuum chamber is located and has a lower vacuum degree than the first vacuum chamber; and

[0179] a third vacuum chamber, which is adjacent to the first vacuum chamber on the side where the first outlet of the first vacuum chamber is located, and has a lower vacuum degree than the first vacuum chamber;

[0180] The second vacuum chamber has: a second inlet, into which the strip metal plate is fed by the conveying mechanism from the one end side; and a second outlet, into which the strip metal plate is fed from the one end side by the conveying mechanism, and out of which the strip metal plate is fed from the one end side. The second outlet is connected to the first inlet, whereby the second vacuum chamber is connected to the first vacuum chamber.

[0181] The third vacuum chamber comprises: a third inlet, into which the welded pipe produced on the portion of the strip metal plate located on the one end side and sent out of the first outlet by the conveying mechanism is sent; and a third outlet, through the use of the conveying mechanism to feed the welded pipe produced on the portion of the strip metal plate located on the one end side into the third inlet, the welded pipe is sent out of the third outlet, the third inlet is connected to the first outlet, and thus the third vacuum chamber is connected to the first vacuum chamber.

[0182] (Note 14)

[0183] The manufacturing apparatus of the welded pipe according to Supplementary Note 13, wherein:

[0184] The first inlet, the second inlet, and the second outlet have a first gap between the flat metal strip and the flat metal strip in a state where the metal strip can slide.

[0185] The first outlet, the third inlet, and the third outlet have a second gap between the first outlet and the welded pipe so that the welded pipe can slide when the welded pipe produced at the portion of the band-shaped metal plate located at the one end side is inserted therethrough.

[0186] (Note 15)

[0187] The manufacturing device of a welded pipe according to any one of Supplementary Notes 10 to 14, wherein:

[0188] One end of the welding tube located outside the first vacuum chamber is closed, and the internal space of the welding tube is the same vacuum as that of the interior of the first vacuum chamber.

[0189] (Note 16)

[0190] The manufacturing device of a welded pipe according to any one of Supplementary Notes 10 to 15, wherein:

[0191] The manufacturing device of the welded pipe further comprises:

[0192] a vacuum gauge for measuring the vacuum degree of the inner space of the first vacuum chamber; and

[0193] A control device determines whether or not the welded pipe produced by the electron beam welding machine has a welding defect based on the measurement value of the vacuum gauge.

[0194] (Note 17)

[0195] The manufacturing device of a welded pipe according to any one of Supplementary Notes 10 to 15, wherein:

[0196] The manufacturing device of the welded pipe further comprises:

[0197] an optical leak detector for determining the vacuum degree of the internal space of the first vacuum chamber by measuring a spectrum of light emitted by causing electrons to collide with a gas in a space connected to the first vacuum chamber to determine the pressure of the gas; and

[0198] A control device determines whether or not the welded pipe produced by the electron beam welding machine has a welding defect based on the vacuum degree of the internal space obtained by the optical leak detector.

[0199] The present disclosure is capable of various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. In addition, the above-mentioned embodiments are used to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is not shown by the embodiments, but by the claims. Moreover, various modifications implemented within the scope of the claims and the equivalent disclosures are considered to be within the scope of the present disclosure.

[0200] This application is based on Japanese Patent Application No. 2022-95328 filed on June 13, 2022. In this specification, the specification, claims, and drawings of Japanese Patent Application No. 2022-95328 are incorporated herein by reference in their entirety.

[0201] Description of symbols

[0202] 1: welding pipe manufacturing device; 2: strip metal plate; 3: tubular body; 4: welding pipe part; 5: joint; 10: uncoiler; 11: connecting machine; 12: storage tank; 13, 14: marking processing machine; 15: forming machine; 16: welding machine; 17: drawing machine; 18: cutting machine; 19: winding machine; 20-22: vacuum chamber; 23, 24: conveying roller; 25: through hole; 30-35: blanking roller; 36-39: finishing roller; 40: vacuum chamber; 41: electron beam welding machine; 42: connecting hole; 50, 51: sealing member; 60: bolt; 61: supporting rod; 70: optical leak detector; 80: control device; 81: CPU; 82: memory; 111: bracket; 131-133: tension adjustment roller; 181: cutter; 191: winding part; 201: inlet; 202: outlet; 205, 206: gap; 211: inlet; 212: outlet; 215, 216: gap; 221: inlet; 222: outlet; 225, 226: gap; 301: convex part; 311: concave part; 321: convex part; 331: concave part; 341: convex part; 351: concave part; 361, 381: fin part.

Claims

1. A method for manufacturing a welded pipe, comprising the steps of: causing an electron beam to collide with a first end face and a second end face of a tubular body to weld the first end face and the second end face to each other, thereby manufacturing the welded pipe, wherein: The tubular body is formed by bending a strip-shaped metal plate into a tubular shape in a width direction, and the first end surface of the strip-shaped metal plate in the width direction faces the second end surface located on the opposite side of the first end surface.

2. The method for manufacturing a welded pipe according to claim 1, wherein: The method for manufacturing a welded pipe further comprises the steps of: bending the strip metal plate into a tubular shape in the width direction in a vacuum space, thereby forming the tubular body in a shape in which the first end face and the second end face face each other; In the step of manufacturing the welded pipe, the electron beam is caused to collide with the first end face and the second end face of the tubular body in the vacuum space to weld the first end face and the second end face to each other.

3. The method for manufacturing a welded pipe according to claim 2, wherein: The method for manufacturing a welded pipe further comprises the steps of: feeding the strip-shaped metal plate from one end side in the direction in which the strip extends into a first vacuum chamber having the vacuum space; In the step of forming the tubular body, a first portion of the strip-shaped metal plate located at the one end side is bent into a tubular shape along the width direction inside the first vacuum chamber, thereby forming the tubular body at the first portion. In the step of manufacturing the welded pipe, the electron beam is caused to collide with the first end face and the second end face of the tubular body formed in the first portion inside the first vacuum chamber to weld the first end face and the second end face to each other.

4. The method for manufacturing a welded pipe according to any one of claims 1 to 3, wherein: The method for manufacturing the welded pipe further comprises the steps of: forming grooves on the plate surface of the strip metal plate in a vacuum space; In the process of manufacturing the welded pipe, in the vacuum space, the electron beam is caused to collide with the first end face and the second end face of the tubular body formed by bending the strip metal plate with the plate surface having the groove facing inward, thereby welding the first end face and the second end face to each other.

5. The method for manufacturing a welded pipe according to claim 4, wherein: The method for manufacturing a welded pipe further comprises the steps of: feeding the strip-shaped metal plate from one end side in the direction in which the strip extends into a first vacuum chamber having the vacuum space; In the step of forming the groove, the groove is formed on a plate surface of a first portion of the band-shaped metal plate located on the one end side inside the first vacuum chamber. In the process of making the welded pipe, inside the first vacuum chamber, the electron beam is made to collide with the first end face and the second end face of the tubular body formed in the first portion by bending the first portion of the strip metal plate with the plate surface having the groove facing inward, and the first end face and the second end face are welded to each other.

6. The method for manufacturing a welded pipe according to claim 3 or 5, wherein: The method for manufacturing a welded pipe further comprises the steps of: sending out the welded pipe produced in the first portion from the first vacuum chamber, A second vacuum chamber adjacent to the first vacuum chamber and having a lower vacuum degree than the first vacuum chamber is provided on the side of the first vacuum chamber at the one end side where the strip-shaped metal plate is fed. On the side of the first vacuum chamber from which the welding pipe is sent out, a third vacuum chamber is provided adjacent to the first vacuum chamber and has a lower vacuum degree than the first vacuum chamber. In the step of feeding the strip-shaped metal plate into the first vacuum chamber, the strip-shaped metal plate is fed into the first vacuum chamber via the second vacuum chamber. In the step of sending out the welded tube from the first vacuum chamber, the welded tube is sent out from the first vacuum chamber to the outside via the third vacuum chamber.

7. The method for manufacturing a welded pipe according to any one of claims 3, 5 and 6, wherein: In the process of manufacturing the welded pipe, one end of the welded pipe is closed, and the internal space of the welded pipe is the same vacuum as the interior of the first vacuum chamber.

8. The method for manufacturing a welded pipe according to any one of claims 1 to 7, wherein: The step of manufacturing the welded pipe includes the step of measuring the degree of vacuum of a space where the electron beam collides with the first end surface and the second end surface using a vacuum gauge, and determining the presence or absence of a welding defect based on the measured value of the degree of vacuum.

9. The method for manufacturing a welded pipe according to any one of claims 1 to 7, wherein: The process of making the welded pipe includes the following steps: causing electrons to collide with gas located in another space to emit light, the other space being connected to the space where the electron beam collides with the first end face and the second end face, measuring the spectrum of the light to determine the pressure of the gas, thereby determining the vacuum degree of the space where the electron beam collides, and judging whether there are welding defects based on the determined vacuum degree.

10. A device for manufacturing a welded pipe, comprising: a first vacuum chamber that accommodates a tubular body formed by bending a strip-shaped metal plate in a width direction into a tubular shape, wherein a first end face in the width direction of the strip-shaped metal plate faces a second end face located on an opposite side to the first end face; and An electron beam welding machine causes an electron beam to collide with the first end face and the second end face of the tubular body inside the first vacuum chamber to weld the first end face and the second end face to each other, thereby manufacturing a welded pipe.

11. The manufacturing apparatus for a welded pipe according to claim 10, wherein: The welded pipe manufacturing device further includes a conveying mechanism that conveys the strip-shaped metal plate into the first vacuum chamber from one end side in the direction in which the strip extends. The first vacuum chamber has: a first inlet into which the strip-shaped metal plate is fed from the one end side; as well as a first outlet, wherein the strip metal plate is fed from the one end side to the first inlet by the feeding mechanism, and the welded pipe produced at the first portion located at the one end side is fed out of the first outlet, wherein the welded pipe is formed by welding the second end face of the tubular body to the first end face by the electron beam welding machine, A forming roller is accommodated in the internal space of the first vacuum chamber. The forming roller bends the first portion of the strip metal plate sent into the first vacuum chamber from the first entrance by the conveying mechanism into a tubular shape along the width direction, and forms a tubular body in the first portion in which the first end face and the second end face are opposite to each other.

12. The manufacturing apparatus for a welded pipe according to claim 11, wherein: A groove forming roller is accommodated in the internal space of the first vacuum chamber, and the groove forming roller forms grooves on the plate surface of the strip-shaped metal plate fed into the first vacuum chamber from the first inlet by the feeding mechanism. The forming roller forms the tubular body by bending the first portion of the strip-shaped metal plate in a state where the plate surface on which the groove is formed faces inward.

13. The manufacturing apparatus for a welded pipe according to claim 11 or 12, wherein: The manufacturing device of the welded pipe further comprises: a second vacuum chamber, which is adjacent to the first vacuum chamber on the side where the first inlet of the first vacuum chamber is located, and has a lower vacuum degree than the first vacuum chamber; as well as a third vacuum chamber, which is adjacent to the first vacuum chamber on the side where the first outlet of the first vacuum chamber is located, and has a lower vacuum degree than the first vacuum chamber; The second vacuum chamber has: a second inlet, into which the strip-shaped metal plate is fed from the one end side by the feeding mechanism; and a second outlet, by using the conveying mechanism to feed the strip metal plate from the one end side into the second inlet, the strip metal plate is fed out of the second outlet from the one end side, the second outlet is connected to the first inlet, thereby the second vacuum chamber is connected to the first vacuum chamber, The third vacuum chamber has a third inlet into which the welded pipe produced on the first portion of the strip metal plate and sent out of the first outlet by the conveying mechanism is sent; and a third outlet, wherein the welding pipe produced on the first part of the strip metal plate is fed into the third inlet by the conveying mechanism, and the welding pipe is fed out of the third outlet, and the third inlet is connected to the first outlet, thereby the third vacuum chamber is connected to the first vacuum chamber.

14. The manufacturing apparatus for a welded pipe according to claim 13, wherein: The first inlet, the second inlet, and the second outlet have a first gap between the flat metal strip and the flat metal strip in a state where the metal strip can slide. The first outlet, the third inlet, and the third outlet have a second gap between the first outlet and the welded pipe so that the welded pipe can slide when the welded pipe produced in the first portion of the strip metal plate is inserted therethrough.

15. The manufacturing apparatus for a welded pipe according to any one of claims 10 to 14, wherein: One end of the welding tube located outside the first vacuum chamber is closed, and the internal space of the welding tube is the same vacuum as that of the interior of the first vacuum chamber.

16. The manufacturing apparatus for a welded pipe according to any one of claims 10 to 15, wherein: The manufacturing device of the welded pipe further comprises: a vacuum gauge for measuring the vacuum degree of the inner space of the first vacuum chamber; and A control device determines whether or not the welded pipe produced by the electron beam welding machine has a welding defect based on the measurement value of the vacuum gauge.

17. The manufacturing apparatus for a welded pipe according to any one of claims 10 to 15, wherein: The manufacturing device of the welded pipe further comprises: an optical leak detector for measuring a spectrum of light emitted by causing electrons to collide with a gas in a space connected to the first vacuum chamber to obtain a pressure of the gas, thereby obtaining a vacuum degree of the internal space of the first vacuum chamber; as well as A control device determines whether or not the welded pipe produced by the electron beam welding machine has a welding defect based on the vacuum degree of the internal space obtained by the optical leak detector.

Images