JP2018134643A - Method and device for molding pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for molding a pipe, which allow manufacture of a round pipe with a bore diameter of a few inches to several tens of inches, in a small number of steps (number of processes and stands), while restricting nonsteady deformation, such as sagging at a tip part and a tail end part of a material, that is becoming a problem when using a sheet material as a molding raw material.SOLUTION: A BD stand 10 is constituted of a pair of revolving units 11 and 11. The FP stand 20 arranged at the next stage of the BD stand 10 is one stand constituted of 3 rolls using a revolving unit 21 as an upper unit, and using molding rolls 22 and 23 as a side unit and a lower unit. The pair of revolving units 11 and 11 in the BD stand 10, and the revolving unit 21 in the FP stand 20 are overlapped at an adjacent side. In the overlapped zone, the vicinity of both edge parts of an open pipe is pressed by side support rolls 31 and 31 on both sides, while the open pipe is supported on an auxiliary bottom roll 32 which can be ascended and descended.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for forming a tube used for manufacturing a round tube or the like from a metal material coil or a sheet metal material having a required length.

  One method of forming a tube is called ODF. One of them is a forming method using a giant forming arc in which a giant forming roll is virtually imagined by an endless die array, and is described in Patent Document 1.

  This molding method supports a hole die array in which a hole die provided with a molding hole mold facing outward is connected to an endless line so as to be able to turn on an endless track, and in a part of the hole mold in the turning direction, A swivel unit provided with an arc of a huge radius assuming a huge forming roll is used, and an effect equivalent to the forming by the huge forming roll can be obtained by a small forming stand.

  Usually, application of the swivel unit as an upper unit, a lower unit, and side units on both sides, for example, as a sizing stand or a fin pass stand is considered.

  Another ODF is a forming method that bends a plate material from a flat plate to an open pipe by restraining both edge portions of the plate material between a pair of endless die rows and moving the die. ing.

  In this molding method, a pair of swivel units that support a swivel die row in which a swivel die having a forming hole mold facing outwardly and swivelly connected to an endless row is supported on an endless track. It is placed opposite to form a straight section where the interval gradually decreases, and the molding holes on both sides constrain both edges of the molding material while supporting the molding material entering the molding section with the bottom roll group. Thus, the molding material on both sides changes the swing angle, and the molding material is continuously bent into an open pipe.

  By using this forming stand as a breakdown stand (BD stand) and arranging two to three fin pass roll stands and a squeeze roll stand on the downstream side, a relatively small number of steps (number of steps, stand) A high-quality welded pipe can be easily manufactured. In addition, even when a sheet material is used as the forming material, unsteady deformation such as sagging is rarely caused at the material front end portion and the material tail end portion.

  However, it is difficult to manufacture a round tube having a diameter of several inches to several tens of inches.

  In other words, when a sheet material is used as a molding material, the caliber is reduced with a small number of steps (number of steps, number of stands) while suppressing unsteady deformation such as sagging at the front end and tail end of the material, which is a particular problem. A pipe forming method that can produce round tubes of several inches to several tens of inches has not been proposed yet.

Japanese Patent No. 5057467 Japanese Patent No. 5523579

  The object of the present invention is to reduce the number of steps (number of steps, number of stands) while suppressing unsteady deformation such as sagging at the leading end and tail end of the material, which is particularly problematic when a sheet material is used as a molding material. Accordingly, it is an object of the present invention to provide a method and apparatus for forming a pipe capable of manufacturing a round pipe having a diameter of several inches to several tens of inches.

  In order to achieve the above object, the inventors of the present invention have a pair of swiveling units, each having a swiveling die row connected to an endless row, swung on an endless track, as a BD stand, and a fin path on the downstream side. Focusing on the method of forming a tube by arranging a roll stand and a squeeze roll stand in series, in order to further improve the formability, instead of a fin pass roll stand, a hole in which a hole die is connected in an endless row We studied the placement of a 4-unit fin pass stand (FP stand) that used a swivel unit that swivels and moves a die array on an endless track as an upper unit, a lower unit, and both side units.

  As a result, the formability is improved and the process from the breakdown start to the end of the fin pass can be completed in two steps. However, the equipment cost increases due to the four units of the FP stand, the tool change time becomes long, and foreign matter is mixed. It has been found that this problem occurs.

  Therefore, the present inventors studied to apply the turning unit only to the upper unit of the FP stand, and to substitute the lower unit and the side units on both sides with rolls. As a result, it has been found that the problem of equipment cost, tool replacement time, and foreign matter contamination can be solved while maintaining high formability.

  In addition, the phase around the pass line of the swivel unit is shifted between the BD stand and the FP stand, so that both swivel units can be placed close to each other and can be overlapped. It was found that the material can be continuously constrained from the end of the fin pass to the end of the fin pass, and the formability can be greatly improved.

  That is, in the BD stand, a pair of swivel units are arranged in a V shape as left and right units on both sides of the pass center, and in the FP stand, one swivel unit is vertically arranged on the pass center as an upper unit. Even if the swivel units are arranged close to each other, mutual interference is avoided, and the forming start side of the swivel unit in the FP stand is located between the end portions of the pair of swivel units in the BD stand (between the arcuate swivel return portions). It is also possible to insert and arrange the end portion (arc-shaped turning return portion), so that the spring pack between the stands can be suppressed to a very small size.

  In particular, when the forming material is a sheet material, roll forming itself is difficult because the material tip and the material tail end are poorly formed, but in this method, from the material tip to the material tail end. Therefore, it is possible to form not only the coil material but also a sheet material with particularly bad formability at both ends, with good yield.

  Also, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other in series, and preferably, the swivel units are overlapped on the close side, and then the edge portion of the open pipe that exits the BD stand Effectiveness of disposing a side support roll capable of pressing the vicinity in the proximity part of the swivel unit, effectiveness of extending the bottom roll group in the BD stand to the proximate part of the swivel unit, and upstream side of the lower roll in the FP stand In addition, the effectiveness of adjusting the pass line height of the auxiliary bottom roll by arranging the auxiliary bottom roll so that it can be moved up and down in proximity to the lower roll has been found.

  In addition, when the BD stand using the swivel unit and the FP stand are arranged close to each other in series, or when the FP stand is arranged close to the next stage of the breakdown roll stand group, the formability from the start of breakdown to the fin path is good. Therefore, just by placing a sizing roll stand (SZ stand) consisting of two upper and lower two-way rolls or four upper and lower, right and left rolls on the downstream side of the FP stand, it becomes possible to perform external surface welding on the next stand, and the number of steps as a whole ( It has been found that a welded tube can be manufactured with the number of processes and the number of stands.

  A stand for outer surface welding, that is, an outer surface welding stand is, for example, a tack weld stand (TW stand), and specifically, the TW stand has a large number of small-diameter rollers arranged in parallel along the longitudinal direction of the raw tube. A roller beam stand with a roller beam placed at multiple locations in the circumferential direction of the open pipe. By placing a welder such as a TIG welder on the top of the open pipe, both edge parts of the open pipe can be seen from the outer surface side. Weld continuously.

  In addition, the TW stand is a TW stand in which the roller beam arranged at the top is shortened and a space for arranging the welding machine is secured on the downstream side. In addition, the TW stand is a TW stand in which a roller beam disposed at a lower portion is replaced with a bottom roll group including a plurality of concave rolls.

  As for welding, in order to further improve the quality of the outer surface welding, a pair of upper and lower inner surfaces that support the upper inner surface and lower inner surface of the raw pipe (open pipe) at the drawing position of the SZ stand, respectively. It is effective to arrange a roller using a mandrel arranged in a raw pipe (open pipe). Specifically, by arranging a pair of upper and lower inner surface support rollers at the throttle position of the SZ stand, It has been found that the contact state of the end surfaces of both edge portions of the (open pipe) to be welded becomes extremely good, and the quality of the subsequent outer surface welding is kept constant and good.

  Furthermore, when the BD stand and the FP stand using the swivel unit are arranged close to each other in series, or when the FP stand is arranged close to the next stage of the breakdown roll stand group, the formability from the breakdown start to the fin path is good. In addition, since the BD stand also restrains the molding material in the circumferential direction at both edges, the swivel unit in the FP stand does not necessarily require a fin in the hole die, and the FP squeeze function (both It has been found that it is possible to provide a function of adhering edges. In order to distinguish the hole type die from each hole type die of the swivel unit in the FP stand from the roller type SZ stand disposed on the downstream side of the FP stand, a composite type SZ stand (combination of a swivel unit and a roll unit) This is called a type SZ stand.

  Further, with respect to the composite type SZ stand, the upper and lower sides 1 respectively support the upper inner surface and the lower inner surface of the raw pipe (open pipe) in contact with and support the raw pipe (open pipe) at the throttle position in the composite type SZ stand. The pair of inner surface support rollers are disposed using a mandrel disposed in the raw pipe (open pipe), and preferably positioned upstream of the pair of inner support rollers to contact and support the upper inner surface of the raw pipe (open pipe). By arranging the fin-supported upper surface support roller using the mandrel, the squeeze function at the squeezing position and the rolling prevention function by the fin at the upstream side are synergistic, so that the end position of both edge end surfaces to be welded can be matched. The outer surface welding quality is further improved by being held as specified, and a pair of upper and lower inner surface support rods to the throttle position in the roller type SZ stand described above. By synergistic placement of la, the outer surface weld quality is found to be even further improved.

  In addition, the arrangement of the upper and lower inner surface support rollers by the mandrel to the composite SZ stand, preferably the arrangement of the upper and lower pair of inner surface support rollers and the arrangement of the finned inner surface support rollers, the contact state of both edge end surfaces. If it is based on the improvement effect and the maintenance of the weld seam position, the inner surface supporting rollers, especially the inner surface supporting roller for the upper inner surface are shifted to the downstream side of the throttle position, and the welding torch is arranged at the throttle position. As a result, it has been found that internal welding with extremely high welding quality is possible, and as a result, it is possible to omit the welding stand and further the roller type SZ stand.

The present invention was developed on the basis of such knowledge,
A pair of swivel units, which support a swivel die row in which endless swivel dies, each having a forming hole mold facing outwardly and swingably connected, can be swung on an endless track, are linearly spaced between them. Oppositely arranged so as to form a gradually decreasing molding section, while supporting the molding material entering the molding section with the bottom roll group, both edge portions of the molding material are constrained by the molding hole molds on both sides and moved synchronously. A BD stand that continuously bends the molding material into an open pipe by changing the swing angle of the mold hole molds on both sides,
A die array in which a hole die with the forming hole mold facing outward is connected to an endless row is supported so as to be able to turn on an endless track, and a huge forming roll is assumed in a part of the hole shape in the turning direction. A swivel unit with an arc of a radius is used for the upper unit, and an FP stand using a roll for the lower unit and the side unit is arranged in series,
The pair of swivel units in the BD stand and the swivel unit in the FP stand are arranged close to each other, and preferably the pair of swivel units in the BD stand and the swivel unit in the FP stand overlap on the close side. This is a tube forming method and apparatus for forming a tube by inserting and arranging an end portion on the forming start end side of the turning unit in the FP stand between end portions on the forming end side of the pair of turning units.

  Such a tube forming method and apparatus are shown in FIG. 1 and FIG. 2 or FIG. In the figure, 10 is a BD stand, 11 and 11 are a pair of turning units in the BD stand 10, 12 is a bottom roll group in the BD stand 10, 20 is an FP stand, 21 is a turning unit in the FP stand 20, 22 is A side unit roll in the FP stand 20, a lower unit roll in the FP stand 20, and an overlap portion 30 between the pair of turning units 11 and 11 in the BD stand 10 and the turning unit 21 in the FP stand 20. 1 and 2 or 3, the pair of turning units 11 and 11 in the BD stand 10 and the turning unit 21 in the FP stand 20 are close to each other. In FIGS. 1 and 2, an overlap portion 30 is particularly formed. ing.

  That is, the present invention completes the molding from a flat plate to an open pipe in one step by a small-sized and easy-to-resize BD stand using a pair of swivel units, and springs back the open pipe from the BD stand. It is sent to the FP stand without making it, and in the FP stand, efficient fin pass molding is performed by a single stand configuration that uses a turning unit only in the upper unit and is easy to change in size.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably, both swivel units are overlapped, and the vicinity of the edge portion of the open pipe exiting the BD stand is A pipe forming method and apparatus for forming a pipe by arranging a pair of pressable side support rolls in the vicinity of the swivel unit, preferably an overlap part.

  A method and apparatus for forming such a tube is shown in FIG. In the drawing, reference numeral 31 denotes a side support roll disposed on the overlap portion 30.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably the both roll units are overlapped, and the bottom roll group in the BD stand is attached to the swivel unit. A pipe forming method and apparatus for forming a pipe by extending and arranging it to an adjacent portion, preferably an overlap portion.

  Such a tube forming method and apparatus is shown in FIG. 5, and 32 is a bottom roll in which an overlap portion 30 is extended.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably, both swivel units are overlapped, and the vicinity of the edge portion of the open pipe exiting the BD stand is One or more side support rolls that can be pressed are arranged in the vicinity of the swivel unit, preferably the overlap part, and the bottom roll group in the BD stand is arranged to extend to the vicinity of the swivel unit, preferably the overlap part. A pipe forming method and apparatus for forming a pipe.

  A method and apparatus for forming such a tube is shown in FIG.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably both swivel units are overlapped, and on the upstream side of the lower unit roll in the FP stand, This is a pipe forming method and apparatus in which an auxiliary bottom roll is disposed so as to be movable up and down in close proximity to a lower unit roll, and a pipe is formed by adjusting the pass line height of the auxiliary bottom roll.

  Such a tube forming method and apparatus is shown in FIG. 7, where 24 is an auxiliary bottom roll. The bottom roll 32 extended to the overlap portion 30 can also serve as the auxiliary bottom roll 24.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably both swivel units are overlapped with each other on the upstream side of the lower roll in the FP stand. An auxiliary bottom roll is arranged so as to be able to move up and down in close proximity to the roll, and an SZ stand consisting of two upper and lower two rolls or four upper and lower and right and left rolls is arranged at the next stage of the FP stand. A pipe forming method and apparatus for forming a pipe by adjusting the amount and the pass line height of an auxiliary bottom roll.

FIG. 8 shows such a tube forming method and apparatus. 40 is an SZ stand disposed at the next stage of the FP stand 20, 41 is an upper and lower two-way roll, and 42 is a left and right two-way roll.
The bottom roll 32 extended to the overlap portion 30 also serves as the auxiliary bottom roll 24.

  According to the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably, both swivel units are overlapped, and the inner surface of each hole die of the swivel unit in the FP stand. A pipe forming method and apparatus for forming a pipe by providing a fin in the center.

  In the present invention, the fin is omitted, or a concave relief portion for inner surface tack welding is provided in the center of the inner surface of each hole die in place of the fin, and inner surface tack welding of the open pipe in the FP stand. It is the formation method and apparatus of the pipe | tube which performs.

  In the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, preferably, after both swivel units are overlapped, an SZ stand is arranged in the next stage of the FP stand, Furthermore, the present invention is a pipe forming method and apparatus in which a TW stand is arranged at the next stage and both edge portions of the open pipe are welded to the outer surface in-line.

  The TW stand is, for example, a roller beam stand in which a plurality of small-diameter rollers arranged in parallel along the longitudinal direction of the raw tube are arranged at a plurality of locations in the circumferential direction of the open pipe. By arranging a welding machine such as a welding machine, both edge portions of the open pipe are continuously welded from the outer surface side. When the roller beam is disposed on the top of the open pipe, the roller beam is shortened to secure a space for arranging the welding machine.

  Further, the present invention is a pipe welding method and apparatus in which an SZ stand is arranged at the next stage of the FP stand and a TW stand is arranged at the next stage, and both edge portions of the open pipe are welded to the outer surface in-line. .

  The TW stand is, for example, a roller beam stand in which a plurality of small-diameter rollers arranged in parallel along the longitudinal direction of the raw tube are arranged at a plurality of locations in the circumferential direction of the open pipe. By arranging a welding machine such as a welding machine, both edge portions of the open pipe are continuously welded from the outer surface side. When the roller beam is disposed on the top of the open pipe, the roller beam is shortened to secure a space for arranging the welding machine.

  In the present invention, the SZ stand is arranged at the next stage of the FP stand, the TW stand is arranged at the next stage, and the upper inner surface and the lower inner surface of the open pipe are placed in the open pipe at the throttle position of the SZ stand. A pipe welding method and apparatus in which a pair of upper and lower inner surface support rollers which are in contact with each other are arranged using a mandrel, and both edge portions of the open pipe are welded to the outer surface in-line.

  In the present invention, the FP stand is formed as a composite SZ stand by removing the fins of the hole die in the swivel unit, a roller type SZ stand is arranged at the next stage of the composite type SZ stand, and further at the next stage. After arranging the TW stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and the lower inner surface of the open pipe from the inside of the open pipe are disposed at the drawing position of the composite SZ stand using a mandrel. Preferably, on the further upstream side, a finned inner surface support roller that abuts and supports the upper inner surface of the open pipe is disposed using a mandrel, and the pipes are welded on the outer surface in-line at both edges of the open pipe. Method and apparatus.

  In the present invention, the FP stand is formed as a composite SZ stand by removing the fins of the hole die in the swivel unit, a roller type SZ stand is arranged at the next stage of the composite type SZ stand, and further at the next stage. After arranging the TW stand, a pair of upper and lower inner surface supporting rollers that support the upper inner surface and the lower inner surface of the open pipe from the inside of the open pipe are arranged using a mandrel at the throttle position of the roller type SZ stand. In addition, a pair of upper and lower inner surface supporting rollers for abutting and supporting the upper inner surface and the lower inner surface of the open pipe from the inside of the open pipe are arranged using a mandrel at the throttle position of the composite SZ stand, Further on the upstream side, a finned inner surface support roller that contacts and supports the upper inner surface of the open pipe is arranged using a mandrel, Both edges of Punpaipu a welding method and apparatus of the tubes to the outer surface welding in line.

  According to the present invention, the FP stand is formed as a composite SZ stand by removing the fins of the hole die in the swivel unit, and the upper inner surface and the lower inner surface of the open pipe are connected to the open pipe in the composite SZ stand. A pair of upper and lower inner surface support rollers that are in contact with each other is disposed at a position where at least the upper inner surface support roller is shifted to the upstream side of the throttle position of the composite SZ stand by a mandrel disposed in the open pipe. The inner support roller with fins for abutting and supporting the upper inner surface of the open pipe is arranged on the upstream side of the inner surface support roller for the upper inner surface using the mandrel, and welding is performed at the throttle position of the composite SZ stand. A torch is placed using the mandrel, and both edges of the open pipe are welded in-line to the inner surface in-line. A method and apparatus.

  In the tube forming method and apparatus of the present invention, a BD stand is constituted by a pair of swivel units that support an endless rocking die row so as to be turnable on an endless track, and an endless hole die row is provided downstream thereof. The upper unit is a swivel unit supported so as to be able to swivel on an endless track, and an FP stand using rolls is placed on the lower unit and side unit, and a pair of swivel units in the BD stand and a swivel unit in the FP stand are close to each other. By arranging, the process from the breakdown start to the end of the fin pass can be efficiently formed in two steps. In addition, by adopting a swivel unit for the BD stand and the FP stand, the formability is essentially excellent, and a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged in close proximity to each other. Since the spring back of the open pipe in the sheet is suppressed, unsteady deformation such as sagging at the material front end and material tail end, which is particularly problematic when a sheet material is used as a molding material, can be suppressed, and the sheet material And material loss due to deformation of both ends can be reduced.

  Further, the pipe forming method and apparatus of the present invention are arranged such that a pair of swivel units in a BD stand and a swivel unit in an FP stand are arranged close to each other, and preferably both the swivel units are overlapped and then the bottom in the BD stand. By extending the roll group to the adjacent part of the swivel unit, preferably the overlap part, the spring back of the open pipe between the two stands can be more effectively suppressed, so it has excellent formability, especially the molding material. As a result, deformation that becomes a problem when a sheet material is used and material loss due to this can be further reduced.

  In the pipe forming method and apparatus of the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably both swivel units are overlapped before the BD stand is moved out. One or more side support rolls capable of pressing the vicinity of the edge of the open pipe are disposed in the vicinity of the swivel unit, preferably in the overlap part, and the bottom roll group in the BD stand is disposed in the vicinity of the swivel unit, preferably Since it extends to the overlap part, the spring back of the open pipe between both stands can be more effectively suppressed, so it has excellent formability, especially when using sheet material as a molding material. And material loss due to this can be further reduced.

  In the pipe forming method and apparatus of the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other. On the upstream side of the roll, the auxiliary bottom roll can be moved up and down close to the lower roll, and the pass line height of the auxiliary bottom roll can be adjusted. In particular, since the warpage can be effectively corrected, the moldability is excellent.

  In the pipe forming method and apparatus of the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other. An auxiliary bottom roll is arranged on the upstream side of the roll so as to be close to the lower roll so that it can be moved up and down, and an SZ stand consisting of two upper and lower two rolls or four upper, lower, left and right rolls is arranged next to the FP stand. By making it possible to adjust the drawing amount in the SZ stand, the drawing amount in the SZ stand, and the pass line height of the auxiliary bottom roll, a round tube having a diameter of several inches to several tens of inches can be manufactured efficiently and with good moldability.

  In addition, the pipe forming method and apparatus of the present invention have a pair of swivel units in the BD stand and a swivel unit in the FP stand arranged close to each other, and preferably the swivel units in the FP stand are overlapped with each other. By providing a fin at the center of the inner surface of each hole die of the unit, the moldability of the FP stand can be further enhanced.

  In the pipe forming method and apparatus of the present invention, a pair of swivel units in the BD stand and a swivel unit in the FP stand are arranged close to each other, and preferably the two swivel units are overlapped, and the fins are omitted. Alternatively, instead of fins, a concave relief for inner surface tack welding is provided in the center of the inner surface of each perforated die, and the inner surface of the FP stand is subjected to inner surface tack welding to form a thin-walled material. Possible limits can be expanded.

  That is, in the method and apparatus for forming a pipe of the present invention, no buckling occurs on the FP stand exit side, so no wrapping occurs on the sizing stand. For this reason, a large aperture can be added by a sizing stand, and essentially high roundness can be obtained. Still, molding is not easy for thin-walled materials, but the inner surface of the FP stand is tacked on the inner surface of the open pipe so that molding is easy even for thin-walled materials. The effect is great. The roundness of the open pipe can be adjusted by raising and lowering the auxiliary bottom roll.

  Moreover, the pipe welding method and apparatus of the present invention has an SZ stand arranged at the next stage of the FP stand, and an outer surface welding stand such as a TW stand arranged at the next stage, thereby reducing the number of stages as a whole (number of steps). The number of stands) makes it possible to manufacture welded pipes.

  In the pipe welding method and apparatus of the present invention, an SZ stand is arranged at the next stage of the FP stand, and an outer surface welding stand such as a TW stand is arranged at the next stage. By arranging a pair of inner surface support rollers, the outer surface welding quality can be further improved.

  In the pipe welding method and apparatus according to the present invention, the FP stand is formed as a composite SZ stand by removing the fins of the hole die in the swivel unit, and a roller SZ stand is provided at the next stage of the composite SZ stand. In addition, an outer surface welding stand is disposed at the next stage, and a pair of upper and lower inner surface support rollers are disposed at the throttle position of the composite type SZ stand, and the upper surface support with fins is disposed on the upstream side thereof. By arranging the roller, it is possible to improve the outer surface welding quality.

  In the pipe welding method and apparatus of the present invention, the FP stand is formed as a composite SZ stand by removing the fins of the hole die in the swivel unit, and a pair of upper and lower inner surface support rollers are provided in the composite SZ stand. The upper surface support roller with fins is disposed further upstream than the throttle position of the composite type SZ stand, and a welding torch is disposed for the throttle position of the composite type SZ stand. In addition, both inner edges of the open pipe can be efficiently welded on the inner surface in-line.

It is a top view of the shaping | molding apparatus of the pipe | tube which shows the structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows the same structure. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the shaping | molding apparatus of the pipe | tube which shows another structure of this invention. It is a side view of the BD stand and FP stand which are the principal parts of the shaping | molding apparatus which shows embodiment of this invention. It is a top view of the overlap part which is the principal part of the shaping | molding apparatus. It is a front view of the overlap part. It is a 3rd page figure of the turning unit of the FP stand which is the principal part of the shaping | molding apparatus, (a) is a top view, (b) is a side view, (c) is a front view. In the longitudinal front view of the forming die used for the FP stand, (a) has fins, (b) has no fins (with concave relief for internal tack welding), and (c) has no fins (relief) None). It is a side view which shows the structure after the BD stand in the same shaping | molding apparatus. It is a side view of the pipe welding apparatus which shows another embodiment of this invention. FIG. 16 is a cross-sectional view taken along line AA in FIG. 15. It is a side view of the pipe welding apparatus which shows another embodiment of this invention. FIG. 18 is a cross-sectional view taken along line B-B in FIG. 17. It is CC sectional view taken on the line in FIG. It is the DD sectional view taken on the line in FIG. It is a side view of the pipe welding apparatus which shows another embodiment of this invention. It is the EE sectional view arrow figure in FIG. FIG. 22 is a sectional view taken along line F-F in FIG. 21. FIG. 22 is a sectional view taken along line GG in FIG. 21.

  Embodiments of the present invention will be described below.

  The molding apparatus of this embodiment manufactures a welded pipe. As shown in FIGS. 9 to 11, the molding apparatus includes a BD stand 10 and an FP stand 20 that are arranged in series from the upstream side to the downstream side. Although not shown, upstream of the BD stand 10, an entry guide, an edge bend, and a roll bend for reverse bend are sequentially arranged toward the BD stand 10. On the other hand, on the downstream side of the FP stand 20, as shown in FIG. 14, an SZ stand 40 and a TW stand 50 are sequentially arranged from the upstream side to the downstream side.

  The BD stand 10 includes a pair of swivel units 11 and 11 that are arranged symmetrically opposite to each other across the path center, and a bottom roll group 12 that is disposed below the path center. The molding material is molded from a flat plate shape to an open pipe in cooperation with the bottom roll group 12 while passing between the pair of swivel units 11 and 11. Hereinafter, the path center direction (tube axis direction) is referred to as the y direction, the horizontal direction (lateral width direction) perpendicular to the path center direction is referred to as the x direction, and the height direction is referred to as the z direction. Further, for convenience of illustration, the pair of turning units 11 and 11 in the BD stand 10 is shortened to about １ ／ only in the y direction by omitting the central portion.

  Each swivel unit 11 is configured such that the endless die row 11a swivels on an oblong endless track that is long in the direction of the pass line (y direction). Specifically, the endless die row 11a is stretched between a pair of front and rear sprocket units 11b and 11b arranged at intervals in the y direction, and one or both of the pair of front and rear sprocket units 11b and 11b are By being rotationally driven, the endless die row 11a turns on an oblong endless track.

  As shown in FIGS. 2 and 3, the swivel units 11 and 11 on both sides are combined in a V shape when viewed from the front, and serve as a molding section through which the molding material passes between the linear track portions on the adjacent opposing sides. At the same time, they are inclined in the x direction so that the distance between the linear tracks on both sides in the molding section gradually decreases from the upstream side toward the downstream side.

  The endless die row 11a is configured by connecting a large number of forming dies 11c in a turning direction via a die holder 11d. Each of the molding dies 11c has a molding hole mold having an L-shaped cross section that engages with the edge portion of the molding material facing the outside of the swivel ellipse, and the die holder 11d changes the engagement angle with the edge portion of the molding material. It is supported in a swingable manner inside. And when each shaping | molding die 11c moves a shaping | molding area, a rocking | fluctuation angle is continuously changed with the movement, and the engagement angle with respect to an edge part is changed. Specifically, as the molding section moves from the upstream side to the downstream side, the molding hole mold having an L-shaped cross section is gradually directed downward.

  In order to change the angle, a linear copying track is arranged along the forming section. On the side of the die holder 11d, the linear movement caused by the copying of the copying track by the die holder 11d is performed. A conversion mechanism such as a rack and pinion that converts to dynamic motion is attached.

  The swivel units 11 and 11 on both sides are installed on a movable gantry (not shown), and the operation of the movable gantry freely changes the interval between the linear tracks on both sides in the molding section.

  The forming die 11c here is characterized by the fact that it swings, so this forming die 11c is particularly referred to as a swinging die 11c, and the endless die row 11a to which it is connected is particularly referred to as a swinging die row 11a.

  The bottom roll group 12 includes a plurality of concave rolls 12a arranged in the y direction. The plurality of concave rolls 21 supports the molding material moving in the molding section from below, and changes the roll surface from an arc surface with a large radius to an arc surface with a small radius sequentially from the upstream side to the downstream side. At the same time, the Z-direction level at the bottom of the arc-shaped roll surface is sequentially lowered. Incidentally, the Z direction level in the y direction of the swivel units 11, 11 on both sides is substantially constant.

  The FP stand 20 arranged at the next stage of the BD stand 10 is a single unit, three rolls using a turning unit 21 as an upper unit, side unit rolls 22 and 22 as side units on both sides, and a lower unit roll 23 as a lower unit. It is a configuration.

  As shown in FIG. 4, the swivel unit 21 is configured such that the endless die row 21a swivels on an elliptical endless track that is long in the direction of the pass line (y direction), and is arranged vertically on the pass line. Thus, the open pipe passing through the FP stand 20 is pressed from above. That is, the endless die row 21a is stretched between a pair of front and rear vertical sprocket units 21b and 21b arranged at intervals in the y direction, and one or both of the pair of front and rear sprocket units 21b and 21b rotate. By being driven, the endless die row 21a pivots on a vertical oval endless track on the pass line. The length of the turning unit 21 is set to be sufficiently smaller than the length of the pair of turning units 11, 11 in the BD stand 10.

  The endless die example 21a is configured by connecting a large number of molding dies 21c in a turning direction via a die holder 21d. Each of the molding dies 21c has an arc-shaped molding hole mold corresponding to the arc of the open pipe discharged from the BD stand 10, and the molding hole mold faces the outside of the turning ellipse. A fin 21e that fits between both edges of the open pipe is provided at the center in the circumferential direction (see FIG. 13A).

  The lower part of the swivel unit 21, that is, the section along the pass line is a molding section. In this molding section, a virtual circular arc having the same diameter as the giant molding roll is placed in the molding hole mold of the endless die example 21a. The endless track is curved downward and convex so that the same radius of curvature and arc length as those of the portion are given. The upper portion of the swivel unit 21 may be linear, but here, like the lower portion, the same shape as a part of a virtual circular arc having the same diameter as the giant forming roll is formed in the forming hole mold of the endless die example 21a. The endless track was curved upward so that the radius of curvature and the arc length were given.

  Since the forming die 21c in the swivel unit 21 has a large characteristic point in a forming hole mold with fins, this forming die 21c is particularly referred to as a hole die 21c, and the endless die row 21a to which the forming die 21c is connected is particularly referred to as a hole die row 21a. Called.

  Each of the side unit rolls 22 and 22 and the lower unit roll 23 is a concave roll, and has an arc-shaped roll surface corresponding to the arc of the open pipe discharged from the BD stand 10.

  The pair of turning units 11 and 11 in the BD stand 10 and the turning unit 21 in the next stage FP stand 20 overlap on the close side. Specifically, it is vertically arranged above the path center between the downstream ends of the pair of swivel units 11 and 11 arranged in a V shape when viewed from the front (that is, between the arcs convex to the downstream side). The upstream end portion of the swivel unit 21 (that is, the arc portion protruding upstream) is inserted and arranged without interference. In addition, side support rolls 31 and 31 are arranged in the proximity of the swivel units 11 and 11 including the overlap portion 30 of the swivel unit 21 so as to sandwich the pass line from both sides, and below the pass line. One auxiliary bottom roll 32 is arranged in a position.

  Here, two pairs of the side support rolls 31 and 31 are arranged close to the direction of the pass line (y direction). The side support rolls 31, 31 on both sides are concave rolls that press the vicinity of both edge portions of the open pipe discharged from between the pair of turning units in the BD stand 10 from both sides, and correspond to the outer surface of the upper half of the open pipe. It has an arc-shaped roll surface. The auxiliary bottom roll 32 is a support concave roll in which the bottom roll group in the BD stand is extended to the downstream side, and is a push-up roller for correcting the warp of the open pipe. Adjustment of the push-up and push-up amount It is possible to move up and down.

  The SZ stand 40 arranged at the next stage of the FP stand 20 includes upper and lower two rolls 41 and 41 and left and right two rolls 42. On the upstream side of the SZ stand 40 (between the FP stand 20), a pair of left and right edge pressing rolls 43 that press both edge portions of the open pipe are disposed, and an auxiliary bottom roll 44 that supports the open pipe from below. Is arranged so that it can be raised and lowered. A pair of left and right edge pressing rolls 43 that press both edge portions of the open pipe are disposed on the downstream side of the SZ stand 40 (between the SZ stand 50). The edge pressing rolls 43, 43 are cage rolls in which a large number of small diameter rollers are arranged in parallel in the longitudinal direction of the raw tube.

  The TW stand 50 arranged at the next stage of the SZ stand 40 has a roller beam 51 in which a plurality of small-diameter rollers are arranged in parallel along the lengthwise direction of the raw tube, at a radial position at a plurality of locations in the circumferential direction of the open pipe. A roller beam stand that can be adjusted. More specifically, on the circumference of the open pipe, the top (0 degrees), shoulder (20 degrees), side (90 degrees), bottom (180 degrees) ), Among the roller beams arranged at the side part (270 degrees) and the shoulder part (340 degrees), the roller beam arranged at the lower part (180 degrees) is replaced with the bottom roll group 52 and the top part ( The roller beam 51 (0 degree) is shortened, and a TIG welding torch 53 for outer surface welding is disposed on the downstream side thereof.

  The bottom roll group 52 uses a relatively large diameter roller for all the other six roller beams 51, while using a relatively large diameter roller, and is provided with a gear at the transfer shaft end of each roller and between the rollers. A reversing gear is arranged on the main body, and all large diameter rollers are synchronously driven in the same direction. By driving the bottom roll group 52, a propulsive force can be applied to the raw pipe (open pipe) in the TW stand 50.

  Next, a method for manufacturing a welded pipe using the molding apparatus of this embodiment will be described as an embodiment of the molding method of the present invention.

  A strip-shaped or sheet-shaped molding material enters the BD stand 10 via each entry guide, edge bend, and reverse bend roll stand (not shown). In the BD stand 10, the molding material passes through the molding section between the pair of turning units 11 and 11. During this time, the molding material is supported by the bottom roll group 12 from below, while both edge portions are constrained by the swing dies 11c, 11c on both sides of the pair of swivel units 11, 11, and synchronized with the swing dies 11c, 11c on both sides. Moving. At this time, the oscillating dies 11c and 11c on both sides oscillate downward and gradually reduce the interval so as to gradually turn the forming hole mold having the inverted L-shaped cross section downward. Thereby, a shaping | molding raw material is shape | molded from a flat plate to an open pipe, while moving a shaping | molding area.

  The cross-sectional height of the molding material gradually increases in the process of molding the molding material from the flat plate to the open pipe. In order to absorb this increase in height, the plurality of concave rolls 12a in the bottom roll group 12 gradually lowers the support level from the upstream side toward the downstream side. Further, the arcs of the roll surfaces of the plurality of concave rolls 12a gradually become smaller in accordance with the change in the cross-sectional shape of the material, particularly the change in the cross-sectional shape of the bottom.

  The open pipe discharged from between the pair of turning units 11 and 11 in the BD stand 10 enters the FP stand 20 and passes there. When the open pipe passes through the FP stand 20, the open pipe is pressed by the swivel unit 21 imagining a giant forming roll from the upper side with the fins 21 e inserted between both edges, and the side unit from both sides. Restrained by the rolls 22 and 22 and restrained by the lower unit roll 23 from below. Thus, the open pipe finishes the fin pass process.

  The open pipe that has finished the fin pass process passes through the SZ stand 40 and is further welded to the TW stand 50 by welding both edge butted portions on the outer surface by the TIG contact torch 53.

  When the open pipe is delivered from the BD stand 10 to the FP stand 20, the open pipe is temporarily released. However, the pair of swivel units 11 and 11 in the BD stand 10 and the swivel unit 21 in the FP stand 20 overlap with each other in the vicinity thereof. For this reason, the overlap release period is short. In addition, in the overlap portion 30 between the turning units 11 and 11 and the turning unit 21, the open pipe is supported from below by the auxiliary bottom roll 32, and the edge portions on both sides are inclined by the two pairs of side support rolls 31 and 31. Pressed from above. For this reason, the big spring pack by temporary release of an open pipe does not arise. Therefore, even if the molding is a short material such as a sheet material, the formability deterioration at the material front end portion and the material tail end portion, and the material loss due to this is minimized.

  In the BD stand 10, since the material support level of the plurality of concave rolls 12a constituting the bottom roll group 12 gradually decreases from the upstream side to the downstream side, the material support points of the plurality of concave rolls 12a (on the arc-shaped roll surface) The line connecting the (bottom) is a downwardly convex curve. For this reason, the open pipe discharged from the BD stand 10 tends to warp. In the overlap portion 30 between the pair of swivel units 11 and 11 in the BD stand 10 and the swivel unit 21 in the FP stand 20, the open pipe is pressed from below by the auxiliary bottom roll 32 and is subjected to three-point bending at this portion. The warping is corrected. In particular, it is possible to completely eliminate this warping by fine level adjustment by raising and lowering the auxiliary bottom roll 32. Moreover, the roundness of the open pipe can be adjusted.

  In addition to these, the BD stand 10 and the FP stand 20 can cope with tube forming over a wide range of dimensions simply by performing the following operations.

  That is, distance adjustment including inclination angle adjustment with respect to the pass line of the pair of turning units 11 and 11 in the BD stand 10, change and support level adjustment of the concave roll 12 a in the bottom roll group 12, and die exchange of the turning unit 21 in the FP stand 20. , Exchange of the pair of side unit rolls 22 and 22, adjustment of the interval, exchange of the lower unit roll 23 and adjustment of the support level, and exchange of the side support rolls 31 and 31 in the overlap portion 30 of the turning units 11 and 11 and the turning unit 21 For example, interval adjustment, replacement of the auxiliary bottom roll 32 and level adjustment.

  Next, another embodiment of the present invention will be described. In the molding apparatus of this embodiment, the fins 21e are omitted from the hole die 21c in the turning unit 21 of the FP stand 20, and instead, as shown in FIG. Is provided at the position of the fin 21e, that is, at the center in the circumferential direction of the arc-shaped forming hole mold, so that both edge portions of the open pipe are abutted in the FP stand 20.

  Further, a mandrel is inserted into the open pipe from the BD stand 10 and extended into the FP stand 20, and both edge butted portions of the open pipe are temporarily welded by laser welding from the inner surface side (inner surface welding). ). The open pipe coming out of the FP stand 20 passes through the SZ stand 40 and is then subjected to outer surface welding at the TW stand 50. When the forming material is a sheet material, it is reasonable to perform the external surface welding offline. When the outer surface welding is performed off-line, the TW stand 50 and the edge pressing roll 41 between the SZ stand 40 and the TW stand 50 are omitted. Other configurations are substantially the same as those of the above-described embodiment.

  Thus, the welded pipe product or the open pipe that has been tack-welded, that is, a semi-finished product of the welded pipe, is discharged from the forming apparatus.

  As a welding method here, plasma welding, TIG welding, etc. other than laser welding are possible, for example. Depending on the type of welding (for example, in plasma welding), as shown in FIG. 13 (c), the concave relief portion 21f can be omitted from the hole die 21c.

  The characteristic points of the molding method and apparatus of the present invention are enumerated based on the embodiments as follows.

  In the BD stand 10, the combination of the pair of swivel units 11 and 11 and the bottom roll group 12 enables efficient and good molding. In the FP stand 20 as well, an efficient and good moldability is formed by using the swivel unit 21 for the upper unit and the molding rolls 22, 22 and 23 for the side units on both sides and the lower unit. Can do. As a result, from the breakdown start to the end of the fin pass can be carried out with only two stands, and the line length can be greatly reduced.

  In the FP stand 20, the turning unit 21 is used for the upper unit, and the molding rolls 22, 22, and 23 are used for the side units on both sides and the lower unit, so that the equipment can be made smaller. It is easy to change the setup according to the size change. In the BD stand 10 as well, the setup change accompanying the size change is easy. For these reasons, a wide variety of products can be molded in one line, and the equipment cost can be greatly reduced.

  After the pair of swivel units 11 and 11 in the BD stand 10 and the swivel unit 21 in the FP stand 20 are overlapped, an auxiliary bottom roll 32 and a pair of side support rolls 31 and 31 are placed on the overlap portion 30. Since it arrange | positions, the spring back of an open pipe between the BD stand 10 and the FP stand 20 can be prevented effectively. For this reason, it is possible to suppress unsteady deformations such as sagging at the material front end and material tail end, which are particularly problematic when a sheet material is used as a molding material, thereby enabling the molding of the sheet material. At the same time, material loss due to deformation of both ends can be eliminated.

  Thus, according to the molding method and apparatus of the present embodiment, the number of steps is small while suppressing unsteady deformation such as sagging at the front end and tail end of the material, which is particularly problematic when a sheet material is used as the molding material. A round tube having a diameter of several inches to several tens of inches can be manufactured by (number of steps, number of stands).

  In addition, according to the molding method and apparatus of the present invention, the auxiliary bottom roll 32 disposed in the overlap portion 30 between the pair of turning units 11 and 11 in the BD stand 10 and the turning unit 21 in the FP stand 20 can be raised and lowered. By making the level adjustment possible, it is possible to effectively prevent the warpage occurring in the material at the BD stand 10. The auxiliary bottom roll 32 not only prevents the spring back of the open pipe at the overlap portion 30 but also contributes to correcting the upper warp of the open pipe. In addition, the roundness of the open pipe can be adjusted.

  Moreover, the moldability in the BD stand 10 is good, and the deterioration of the moldability with the FP stand 20 is prevented by the overlap portion 30 as much as possible. It is possible to omit the fins 21e from the die 21c, and thus even inner surface tack welding on the FP stand 20 is possible. And, by the internal tack welding at the FP stand 20, it becomes possible to further improve the formability, and in particular, the limit for forming a thin material can be expanded.

  Still another embodiment of the present invention will be described with reference to FIGS. This embodiment is a pipe welding apparatus, and is applied to a pipe mill whose basic structure is shown in FIG. As described above, the pipe mill includes the BD stand 10, the FP stand 20, the roll type SZ stand 40, and the TW stand 50 arranged from the upstream side to the downstream side. That is, the FP stand 20 includes a turning unit 21 in which fins are provided on the hole surface of each hole die. The roll-type SZ stand 40 includes upper and lower two rolls 41 and left and right two rolls 42.

  The welding apparatus of this embodiment differs from the welding apparatus employed in the pipe mill of FIG. 14 in that a pair of upper and lower inner surfaces that abut and support the upper inner surface and lower inner surface of the open pipe at the throttle position of the roll-type SZ stand 40. That is, support rollers 45 and 45 are arranged.

  The pair of upper and lower inner surface support rollers 45, 45 are rotatably supported by a mandrel 60 inserted into the open pipe from the overlap portion 30 between the BD stand 10 and the FP stand 20. That is, the mandrel 60 extends from the overlap portion 30 between the BD stand 10 and the composite type SZ stand 20 to the roll type SZ stand 40, and the base end portion thereof is a side support roll disposed on the overlap portion 30. It is attached to 31 support stands. A pair of upper and lower inner surface support rollers 45 and 45 in the roll type SZ stand 40 are rotatably supported at the tip of the mandrel 60. Both rollers are driven in the radial direction of the open pipe by a spring or hydraulic pressure with respect to the mandrel 60.

  When the inner surface support rollers 45, 45 are arranged in the vicinity of the drawing position of the roll type SZ stand 40 and the molding is performed, the contact state between the end surfaces of both edges of the open pipe to be welded becomes good, which is subsequently performed. The quality of the outer surface welding at the TW stand 50 is constant and good.

  Yet another embodiment of the present invention will be described with reference to FIGS. This embodiment is a pipe welding apparatus, and here, as in the embodiment shown in FIGS. 15 and 16, is applied to a pipe mill whose basic configuration is shown in FIG.

  The welding apparatus of the present embodiment is different from the welding apparatus employed in the pipe mill of FIG. 14 in that a pair of upper and lower sides that abut the upper inner surface and lower inner surface of the open pipe at the drawing position of the roll-type SZ stand 40. The inner surface support rollers 45, 45 are arranged, and the FP stand 20 is changed to a composite SZ stand in which fins are excluded from the hole surface of each hole die 21c in the turning unit 21 (FIG. 13). (See (c)), and a pair of upper and lower inner surface support rollers 25 and 25 for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the throttle position of the composite SZ stand to the upstream side thereof, and the upper inner surface of the open pipe The inner support roller 26 with fins for abutting and supporting the inner surface and the inner surface support roller 27 for abutting and supporting the upper inner surface of the open pipe. .

  These inner surface support rollers are rotatably supported by a mandrel 60 inserted into an open pipe from an overlap portion 30 between the BD stand 10 and the composite SZ stand 20. That is, the mandrel 60 extends from the overlap portion 30 between the BD stand 10 and the composite type SZ stand 20 to the roll type SZ stand 40, and the base end portion thereof is a side support roll disposed on the overlap portion 30. It is attached to 31 support stands. A pair of upper and lower inner surface support rollers 45 and 45 in the roll type SZ stand 40 are rotatably supported at the distal end portion of the mandrel 60, and a pair of upper and lower surfaces in the composite type SZ stand 20 are provided in the vicinity of the base end portion. The inner surface support rollers 25, 25, the finned inner surface support roller 26, and the inner surface support roller 27 are rotatably supported. Both rollers are driven in the radial direction of the open pipe by a spring or hydraulic pressure with respect to the mandrel 60.

A pair of upper and lower inner surface support rollers 25, 25 and a finned inner surface support roller 26 are disposed near the throttle position of the composite SZ stand 20, and inner surface support rollers 45, 45 are disposed near the throttle position of the roll type SZ stand 40. When the molding is carried out, the sizing function of the composite SZ stand 20 and the rolling prevention effect of the open pipe are synergistic, so that the butted positions of both edge end surfaces to be welded of the open pipe are maintained as prescribed, and the molding quality is maintained. In combination with the effects of the inner surface support rollers 45, 45 in the roller type SZ stand 40 described above, the quality of the outer surface welding in the subsequent TW stand 50 is further improved and constant.

  As for the inner surface support roller in the composite type SZ stand 40, a pair of upper and lower inner surface support rollers 25, 25 are essential, and it is preferable to combine a finned inner surface support roller 26 for the upper inner surface on the upstream side, and further on the upstream side. Further, it is more preferable to combine the inner surface support roller 27 for the upper inner surface.

  Still another embodiment of the present invention will be described with reference to FIGS. This embodiment is a pipe welding apparatus, and here, in the same manner as the embodiment shown in FIGS. 15 and 16 and the embodiment shown in FIGS. 17 to 20, the pipe mill whose basic configuration is shown in FIG. Has been applied.

  The welding apparatus of this embodiment is different from the welding apparatus adopted in the pipe mill of FIG. 14 in that the FP stand 20 is a composite SZ in which fins are excluded from the hole mold surfaces of the hole molds 21c in the turning unit 21. A pair of upper and lower inner surface support rollers that abut and support the upper inner surface and lower inner surface of the open pipe from the throttle position of the composite SZ stand to the upstream side thereof (see FIG. 13C). 25, 25, a fin-equipped inner surface support roller 26 that abuts and supports the upper inner surface of the open pipe, and an inner surface support roller 27 that abuts and supports the upper inner surface of the open pipe. The welding torch 28 for internal welding of the open pipe is arranged, and the TW stand 50 is omitted.

  Of the pair of upper and lower inner surface support rollers 25, 25, the upper inner surface support roller 25 is displaced to the downstream side of the squeezing position, and the lower inner surface support roller 25 is a diaphragm. Placed in position. Further, the finned inner surface support roller 26 is positioned downstream of the upper inner surface support roller 25, and the inner surface support roller 27 is positioned further downstream of the finned inner surface support roller 26. And the welding torch 28 for inner surface welding is arrange | positioned with respect to the empty space (upper inner surface of an aperture position) formed by the upper inner surface support roller 25 being displaced.

  These inner surface support rollers are rotatably supported by a mandrel 60 inserted into an open pipe from an overlap portion 30 between the BD stand 10 and the composite SZ stand 20. That is, the mandrel 60 extends from the overlap portion 30 between the BD stand 10 and the composite type SZ stand 20 to the throttle position of the composite type SZ stand 20, and its base end portion is disposed in the overlap portion 30. The side support roll 31 is attached to a support stand. The mandrel 60 rotatably supports a pair of upper and lower inner surface support rollers 25, 25, a finned inner surface support roller 26, and an inner surface support roller 27 in the composite SZ stand 20. Both rollers are driven in the radial direction of the open pipe by a spring or hydraulic pressure with respect to the mandrel 60.

  A welding torch 28 for inner surface welding is disposed at the throttle position of the composite SZ stand 20, and a pair of upper and lower inner surface support rollers 25, 25, an inner surface support roller 26 with fins, and an inner surface support roller 27 are disposed from the throttle position to the downstream side. When the molding is performed, the sizing function of the composite type SZ stand 20 and the rolling prevention effect of the open pipe synergize, so that the butt positions of both edge end surfaces to be welded of the open pipe are held as prescribed. As a result of maintaining the welding seam position constant, extremely high quality inner surface welding is performed, and as a result, the step by the outer surface welding stand (TW stand 50) can be omitted.

  As for the inner surface support roller in the composite type SZ stand 40, a pair of upper and lower inner surface support rollers 25, 25 are essential, and it is preferable to combine a finned inner surface support roller 26 for the upper inner surface on the upstream side, and further on the upstream side. Further, it is more preferable to combine the inner surface support roller 27 for the upper inner surface.

  As the welding torch 28 for inner surface welding, a laser irradiation type is used here, but any known one can be used.

Example 1
Assuming a dual 4-inch pipe mill that can produce round tubes of various sizes in the dual-use range of stainless steel, ordinary steel, high-tensile steel, caliber 38.1 mm to 114.3 mm, plate thickness 0.5 mm to 6.0 mm, Commercially available 3D CAD software that adopts the arrangement of entry guide stand, edge bend roll stand, reverse bend roll stand, ODF / BD stand, ODF / FP stand, sizing roll stand, squeeze roller beam stand from the entrance side And the equipment of each stand was designed using the original automatic design and FEM analysis software designed by the inventor.

  The entry guide stand was configured by combining a known side roll and an upper and lower roll. The edge bend roll stand is a combination of a pair of upper rolls that can move and rotate in the material width direction and a pair of lower rolls that can move in the material width direction and move in the height direction. It was set as the structure which can be shared with respect to a diameter. The reverse bend roll stand is configured by combining a known side roll and an upper and lower roll.

  The ODF / BD stand and the ODF / FP stand have the configuration described in the above embodiment, and in particular, as a basic structure, a ball bearing in which a large number of small balls run in an elliptical orbit is incorporated in the unit, The swing arm and pinion is adopted as a mechanism to support the turning and the swing of each die, and the entire device is miniaturized. Also, the BD stand and the FP stand are arranged close to each other, the side support roll, and the auxiliary bottom. The same roll configuration was adopted.

  The sizing roll stand was configured by combining known upper and lower rolls. A squeeze roller beam stand is a roller beam in which a large number of small-diameter rollers are arranged in parallel along the longitudinal direction of the raw tube in order to insert and hold the raw tube formed in a short cylindrical frame. At the top (0 degrees), shoulder (20 degrees), side (90 degrees), bottom (180 degrees), side (270 degrees), shoulder (340 degrees) A configuration was adopted in which the position of the frame can be adjusted in the radial direction. The roller beam at the top is short and a TIG welder was placed near the downstream.

  As a result of actually manufacturing an actual machine based on this design, a 4 inch pipe mill with a line length of only 5 m from the entry guide stand EG stand to the squeeze roller stand SQ stand was obtained.

ODF / BD stand is x direction (w) 2920mm, y direction 2510mm, z direction (h) 2950mm,
BD swivel unit is x direction 710mm, y direction 2500mm, z direction 300mm, weight 1990kg,
ODF / FP stand is 1300mm in x direction, 955mm in y direction, 1600mm in z direction,
The FP swivel unit was 210 mm in the x direction, 930 mm in the y direction, 465 m in the z direction, and weighed 405 kg.

  The following six types of test materials and plate thickness t were used, and a coil material having a diameter of 45 mm and a diameter equivalent to 114.3 mm and a sheet material having a length of 1.5 to 4 m were used.

SUS304, t0.7mm,
X65-70 equivalent material (YS = 544MPa), t1.0mm
X120 equivalent material (YS = 897MPa), t1.0mm
X100 equivalent material (YS = 761MPa), t2.0mm
SS400 (YS = 308MPa), t3.2mm
SS400 (YS = 321MPa), t4.5mm

  First, a total of 12 types of round tubes were molded and manufactured with 6 types of coil materials and 2 types of bores. In all cases, round tubes with the same caliber, roundness and straightness could be manufactured.

  Next, a total of 36 types of round tubes were formed and manufactured with 6 types of materials and 2 types of bores using 1.5m, 2.0m, and 4.0m long sheet materials. In the case of a sheet material, a means for improving the weldability by connecting a tab to the edge of the tip portion was adopted. No matter the length of the sheet material, deformation of the tip and end of the obtained round tube did not occur, and a round tube with a caliber, roundness, and straightness as designed could be manufactured. .

  In addition, it was confirmed that the actual measurement values such as the molding load in each process during the manufacturing described above substantially coincided with the calculated values at the time of design using FEM analysis software.

Example 2
Here, the mold of the swivel unit of the ODF / FP stand in Example 1 had the fins shown in FIG. 5 (a), but this was shown in FIG. A seat-shaped mold was adopted. In addition, another stand is placed between the ODF / BD stand and the ODF / FP stand at the position directly above the return part of the ODF / BD swivel unit. A YAG pulsed fiber laser welder with a laser torch facing upward was placed by guiding the mandrel tip through the molding section position of the ODF / FP stand. Therefore, this ODF stand is called an ODF / weld stand.

  With such a configuration, after forming into a round tube with a BD stand, immediately after being constrained in a mold with a semispherical seat cross section of the ODF / weld stand, spot welding is performed from the inner surface of the tube with a laser welding machine. Temporary welding can be carried out. Thereafter, the sizing process and the welding process from the outer surface can be performed in the same manner as in the first embodiment.

  A sheet material having a length of 1.5 m and 2.0 m used in Example 1 and an X120 equivalent material (t1.0 mm) and a total of four kinds of round tubes with two types of bores, that is, inner surface temporary welding and outer surface main welding were performed. A round tube was formed and manufactured. No matter the length of the sheet material, deformation such as sagging of the end and end of the obtained round tube does not occur, the inner and outer surfaces are welded well, the caliber, roundness, straightness as designed A round tube of the same degree was produced

Example 3
The material ranges from X65 to 70 equivalent material (YS = 544MPa), X100 equivalent material (YS = 761MPa), X120 equivalent material (YS = 897MPa), caliber 323.9mm to 762.0mm, plate thickness 4.8mm to 25.4mm Assuming a combined 30 inch pipe mill that can produce API pipes of various sizes, from the material entry side, entry guide stand, edge bend roll stand, reverse bend roll stand, ODF / BD stand, ODF / weld stand, sizing Using a configuration in which the roll stand and squeeze roller beam stand are arranged in this order, the design of the equipment of each stand is done using commercially available 3D CAD software and original automatic design and FEM analysis software designed by the inventor in the same way as in Example 1. I did it.

  As a result of this design, a 30-inch pipe mill with a line length of 38 m from the EG stand to the SQ stand was obtained.

ODF / BD stand is x direction (w) 10m, y direction 20m, z direction (h) 6.8m,
BD swivel unit is 2m in x direction, 15m in y direction, 1.2m in z direction, weight 127ton,
ODF / FP stand is x direction 4.5m, y direction 3.9m, z direction 6.5m,
The FP swivel unit had an x direction of 1.0 m, a y direction of 3.9 m, a z direction of 2.1 m, and a weight of 28 tons.

  In the calculation values using the simulation software and FEM analysis software, a round tube with an X120 equivalent material (YS = 897 MPa) with a diameter of 323.9 mm and a plate thickness of 19.1 mm, a diameter of 762.0 mm and a plate thickness of 25.4 mm It was confirmed that can be manufactured.

Example 4
In a 4-inch pipe mill whose basic structure is shown in FIG. 14, a welded round tube was actually formed and manufactured using the welding apparatus shown in FIGS. The pipe mill includes a BD stand 10, an FP stand 20, an SZ stand 40 and a TW stand 50 arranged in order from the upstream side to the downstream side. The material is stainless steel, ordinary steel, high strength steel, and the diameter is 38. Various round tubes can be manufactured within a range of 1-14.3 mm and a plate thickness of 0.5-6.0 mm.

  Then, using the mandrel 60 inserted into the open pipe from the overlap portion 30 of the BD stand 10 and the FP stand 20, the upper inner surface of the open pipe is placed at the throttle position where the axes of the four-way rolls in the SZ stand 40 are aligned. Also, a pair of upper and lower inner surface support rollers 45, 45 that contact and support the lower inner surface are disposed. The inner surface support rollers 45, 45 can be moved up and down in the radial direction of the open pipe by a spring.

  A coil material having a diameter equivalent to 114.3 mm, a material equivalent to X120 (YS = 897 MPa) and having a plate thickness t of 1.0 mm and 2.0 mm, and a TIG welder is disposed on the TW stand 50. Thus, two types of welded round tubes with different plate thicknesses were formed and manufactured. By arranging a pair of upper and lower inner surface support rollers 45, 45 at the throttle position of the SZ stand 40, the contact state between the end surfaces of both edges of the open pipe to be welded becomes good, and the quality of the outer surface welding is constant and good. As a result, a welded round tube with a diameter, roundness, and straightness could be manufactured as designed.

Example 5
The welding apparatus used in Example 4 was replaced with that shown in FIGS.

  That is, the FP stand 20 is changed to a composite SZ stand in which fins are removed from the hole mold surface of each hole die 21c in the turning unit 21. Also, using the mandrel 60 inserted into the open pipe from the overlap portion 30 of the BD stand 10 and the composite type SZ stand 20, it is opened at the throttling position where the axes of the four-way rolls in the roll type SZ stand 40 are aligned. A pair of upper and lower inner surface support rollers 45, 45 for abutting and supporting the upper inner surface and the lower inner surface of the pipe are disposed, and the upper inner surface and the lower side of the open pipe from the throttle position in the composite SZ stand 20 to the upstream side thereof. A pair of upper and lower inner surface support rollers 25, 25 for abutting and supporting the inner surface, a finned inner surface support roller 26 for abutting and supporting the upper inner surface of the open pipe, and an inner surface support roller 27 for abutting and supporting the upper inner surface of the open pipe are arranged. did. All of the inner surface support rollers 45, 45 and 25, 25, 26, and 27 can be moved up and down in the radial direction of the open pipe by a spring.

  A coil material having a diameter equivalent to 114.3 mm, a material equivalent to X120 (YS = 897 MPa) and having a plate thickness t of 1.0 mm and 2.0 mm, and a TIG welder is disposed on the TW stand 50. Thus, two types of welded round tubes with different plate thicknesses were formed and manufactured.

  In addition to a pair of upper and lower inner surface support rollers 45, 45 being arranged at the throttle position of the roll type SZ stand 40, a pair of upper and lower inner surface support rollers 25, 25 and fins for the upper inner surface are provided at the throttle position of the composite type SZ stand 20. By arranging the inner surface support roller 26 and the inner surface support roller 27 for the upper inner surface, the sizing function in the composite SZ stand 20 and the rolling prevention effect of the open pipe are synergistic, so that the open pipe will be welded. The abutting position of both edge end faces is maintained as prescribed, and the molding quality is improved. Further, the effect of the inner surface support rollers 45, 45 in the roller type SZ stand 40 is added, thereby further improving the quality of the outer surface welding on the TW stand 50. Constant and good, all with a welded round tube with caliber, roundness and straightness as designed It could be produced.

Example 6
The welding apparatus used in Example 4 was replaced with that shown in FIGS.

  That is, the FP stand 20 is changed to a composite SZ stand in which fins are removed from the hole mold surface of each hole die 21c in the turning unit 21. In addition, a welding torch 28 for inner surface welding is disposed at the drawing position in the composite SZ stand 20 using a mandrel 60 inserted into the open pipe from the overlap portion 30 of the BD stand 10 and the composite SZ stand 20. Further, from the throttle position to the upstream side, a pair of upper and lower inner surface support rollers 25 and 25 for abutting and supporting the upper inner surface and lower inner surface of the open pipe, and an inner surface support roller with fins for abutting and supporting the upper inner surface of the open pipe 26 and an inner surface support roller 27 that contacts and supports the upper inner surface of the open pipe.

  The welding torch 28 is a laser torch capable of irradiating two beams upward on the squeezing point by the side unit roll in the composite SZ stand 20, and is equipped in the YAG pulse fiber laser welding machine. All of the inner surface support rollers 25, 25, 26 and 27 can be moved up and down in the radial direction of the open pipe by a spring.

  A coil material having a diameter equivalent to 114.3 mm, a material equivalent to X120 (YS = 897 MPa) and having a plate thickness t of 1.0 mm and 2.0 mm, and a TIG welder is disposed on the TW stand 50. Thus, two types of welded round tubes with different plate thicknesses were formed and manufactured.

  By combining the sizing function of the composite SZ stand 20 and the anti-rolling effect of the open pipe, the abutting positions of both edge end surfaces to be welded of the open pipe are maintained as prescribed, and the weld seam position is kept constant. As a result, an extremely high quality internally welded pipe was produced.

  A TW stand 50 was disposed on the downstream side of the roll-type SZ stand 40, and outer surface welding was performed following inner surface welding. A 2 m long steel pipe could be manufactured.

10 BD stand 11 Rotating unit 11a Endless die row (oscillating die row)
11b Sprocket unit 11c Molding die (oscillating die)
11d Die holder 20 FP stand (Composite SZ stand)
21 Rotating unit 21a Endless die example (hole die array)
21b Sprocket unit 21c Molding die (hole die)
21d Die holder 21e Fin 21f Concave part 22 Side unit roll 23 Lower unit roll 24 Auxiliary bottom roll 25, 27 Inner surface support roller 26 Inner surface support roller 28 with fin 28 Welding torch for inner surface welding 30 Overlap portion 31 Side support roll 32 Auxiliary bottom Roll 40 SZ stand (roll type SZ stand)
41 Upper and lower rolls 42 Left and right rolls 43 Edge pressing roll 44 Auxiliary bottom roll 45 Inner surface support roller 50 TW stand 51 Roller beam 52 Bottom roll 53 Welding torch for outer surface welding 60 Mandrel

Claims (44)

A pair of swivel units, which support a swivel die row in which endless swivel dies, each having a forming hole mold facing outwardly and swingably connected, can be swung on an endless track, are linearly spaced between them. Oppositely arranged so as to form a gradually decreasing molding section, while supporting the molding material entering the molding section with the bottom roll group, both edge portions of the molding material are constrained by the molding hole molds on both sides and moved synchronously. A BD stand that continuously bends the molding material into an open pipe by changing the swing angle of the mold hole molds on both sides,
A die array in which a hole die with the forming hole mold facing outward is connected to an endless row is supported so as to be able to turn on an endless track, and a huge forming roll is assumed in a part of the hole shape in the turning direction. A swivel unit with an arc of a radius is used for the upper unit, and an FP stand using a roll for the lower unit and the side unit is arranged in series,
A pipe forming method in which a pair of turning units in a BD stand and a turning unit in an FP stand are arranged close to each other to form a pipe. The method for forming a pipe according to claim 1, wherein
In order to allow the swivel unit to overlap between the BD stand and the FP stand, the end of the swivel unit on the molding end side of the FP stand is inserted between the ends of the swivel unit BD stand on the molding end side. A tube forming method in which pipes are arranged and formed. The method for forming a pipe according to claim 1, wherein
A pipe forming method for forming a pipe by arranging a pair of side support rolls capable of pressing the vicinity of an edge of an open pipe coming out of a BD stand in the vicinity of the swivel unit. The method for forming a pipe according to claim 1, wherein
A tube forming method for forming a tube by extending a bottom roll group in a BD stand to a proximity portion of the swivel unit. The method for forming a pipe according to claim 1, wherein
One or more side support rolls that can press the vicinity of the edge of the open pipe that has come out of the BD stand are arranged in the vicinity of the swivel unit, and the bottom roll group in the BD stand is extended to the overlap part of the swivel unit. Then, a method for forming a pipe is performed. The method for forming a pipe according to claim 1, wherein
The bottom roll group in the BD stand is a method of forming a pipe composed of a plurality of concave rolls in which the roll surface becomes an arc surface with a small radius sequentially from an arc surface with a large radius. The method for forming a pipe according to claim 1, wherein
A pipe forming method in which an auxiliary bottom roll is disposed so as to be movable up and down on the upstream side of a lower roll in an FP stand, and a pipe is formed by adjusting a pass line height of the auxiliary bottom roll. The method for forming a pipe according to claim 1, wherein
An auxiliary bottom roll is arranged on the upstream side of the lower roll in the FP stand so that the auxiliary bottom roll can be moved up and down, and an SZ stand made up of two upper and lower two rolls or four upper, lower, left and right rolls is arranged next to the FP stand. And forming a tube by adjusting the drawing amount in the FP stand, the drawing amount in the SZ stand, and the pass line height of the auxiliary bottom roll. The method for forming a pipe according to claim 1, wherein
The swivel unit in the FP stand is a method of forming a tube having a fin at the center of the inner surface of each hole die. The method for forming a pipe according to claim 1, wherein
A method of forming a tube in which fins are omitted from each hole die row of the swivel unit in the FP stand, and the inner surface of the open pipe is tack-welded inside the FP stand. The method for forming a pipe according to claim 1, wherein
An SZ stand consisting of upper and lower two-way rolls or upper and lower, left and right four rolls is arranged at the next stage of the FP stand, and further, both edges of the open pipe are externally welded while restraining the open pipe from the outer surface side. A tube forming method in which a TW stand is arranged and both edge portions of an open pipe are externally welded in-line. A die array in which a hole die with the forming hole mold facing outward is connected to an endless row is supported so as to be able to turn on an endless track, and a huge forming roll is assumed in a part of the hole shape in the turning direction. An SZ stand consisting of upper and lower two-way rolls or upper and lower and left and right four rolls is arranged at the next stage of the FP stand using a turning unit with a circular arc of radius as the upper unit and rolls as the lower unit and the side unit,
Further, in the next stage, a TW stand for constraining the open pipe from the outer surface side and welding both edge portions of the open pipe to the outer surface is disposed, and the pipe welding method for welding both edges of the open pipe in-line to the outer surface. The pipe welding method according to claim 12,
The swivel unit in the FP stand is a welding method for a pipe having a fin at the center of the inner surface of each hole die. The pipe welding method according to claim 13,
At the throttle position of the SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from inside the open pipe are arranged using a mandrel, and both edge portions of the open pipe are arranged. A welding method for pipes that are externally welded inline. The pipe welding method according to claim 12,
The FP stand is a pipe welding method that is a composite SZ stand in which fins are omitted from each hole die of the swivel unit. The pipe welding method according to claim 15,
A pair of upper and lower inner surface support rollers that contact and support the upper inner surface and lower inner surface of the open pipe from within the open pipe are arranged using a mandrel at the throttle position of the composite SZ stand, and both edges of the open pipe Welding method for pipes where the parts are welded inline on the outside. The pipe welding method according to claim 15,
A pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe are arranged using a mandrel at the throttle position of the composite SZ stand, and further upstream of the pair. A pipe welding method in which an inner support roller with fins for abutting and supporting the upper inner surface of an open pipe is arranged using a mandrel, and both edge portions of the open pipe are externally welded in-line. The pipe welding method according to claim 15,
A mandrel is used for a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the roll type SZ stand arranged at the next stage of the composite type SZ stand. And a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe at the throttle position of the composite SZ stand, respectively, using a mandrel, A pipe welding method in which both edges of an open pipe are welded inline. The pipe welding method according to claim 15,
A mandrel is used for a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the roll type SZ stand arranged at the next stage of the composite type SZ stand. And a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and the lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the composite SZ stand using a mandrel, Further, a pipe welding method in which an inner surface supporting roller with fins for abutting and supporting the upper inner surface of the open pipe is arranged on the upstream side by using a mandrel, and both edges of the open pipe are externally welded in-line. The pipe welding method according to claim 15,
In the composite SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe, respectively, at least the upper inner surface support roller is upstream of the throttle position of the composite SZ stand. Place it in a position that deviates,
A welding method for a pipe in which a welding torch for inner surface welding is arranged at the drawing position of the composite type SZ stand, both edge portions of the open pipe are internally welded in-line, and the outer surface is subsequently welded. The pipe welding method according to claim 15,
In the composite SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe, respectively, at least the upper inner surface support roller is upstream of the throttle position of the composite SZ stand. Place it in a position that deviates,
On the further upstream side of the inner surface supporting roller for the upper inner surface, an inner surface supporting roller with fins for contacting and supporting the upper inner surface of the open pipe is disposed,
A welding method for a pipe in which a welding torch for inner surface welding is disposed at the drawing position of the composite type SZ stand, both edges of the open pipe are welded on the inner surface in-line, and then the outer surface is welded. The pipe welding method according to claim 20 or 21,
A pipe welding method in which the TW stand is omitted and both edges of the open pipe are internally welded in-line. A pair of swivel units, which support a swivel die row in which endless swivel dies, each having a forming hole mold facing outwardly and swingably connected, can be swung on an endless track, are linearly spaced between them. Oppositely arranged so as to form a gradually decreasing molding section, while supporting the molding material entering the molding section with the bottom roll group, both edge portions of the molding material are constrained by the molding hole molds on both sides and moved synchronously. A BD stand that continuously bends the molding material into an open pipe by changing the swing angle of the mold hole molds on both sides,
A die array in which a hole die with the forming hole mold facing outward is connected to an endless row is supported so as to be able to turn on an endless track, and a huge forming roll is assumed in a part of the hole shape in the turning direction. A swivel unit with an arc of a radius is used for the upper unit, and an FP stand using a roll for the lower unit and the side unit is arranged in series,
A pipe forming apparatus in which a pair of swivel units in a BD stand and a swivel unit in an FP stand are arranged close to each other. The tube forming apparatus according to claim 23,
In order to allow the swivel unit to overlap between the BD stand and the FP stand, the end of the swivel unit on the molding end side of the FP stand is inserted between the ends of the swivel unit BD stand on the molding end side. An apparatus for forming the arranged pipes. The tube forming apparatus according to claim 23,
A pipe forming apparatus in which a pair of side support rolls capable of pressing the vicinity of an edge portion of an open pipe coming out of a BD stand are arranged in the vicinity of the swivel unit. The tube forming apparatus according to claim 23,
A tube forming apparatus in which a bottom roll group in a BD stand is extended to a vicinity of the swivel unit. The tube forming apparatus according to claim 23,
One or more side support rolls that can press the vicinity of the edge of the open pipe that has come out of the BD stand are arranged in the vicinity of the swivel unit, and the bottom roll group in the BD stand is extended to the overlap part of the swivel unit. Pipe forming equipment. The tube forming apparatus according to claim 23,
The bottom roll group in the BD stand is a pipe forming apparatus composed of a plurality of concave rolls in which the roll surface becomes an arc surface with a small radius sequentially from an arc surface with a large radius. The tube forming apparatus according to claim 23,
An apparatus for forming a pipe in which an auxiliary bottom roll is disposed so as to be movable up and down in the vicinity of the lower roll on the upstream side of the lower roll in the FP stand, and the pass line height of the auxiliary bottom roll can be adjusted. The tube forming apparatus according to claim 23,
An auxiliary bottom roll is arranged on the upstream side of the lower roll in the FP stand so that the auxiliary bottom roll can be moved up and down, and an SZ stand made up of two upper and lower two rolls or four upper, lower, left and right rolls is arranged next to the FP stand. And a pipe forming apparatus capable of adjusting the drawing amount in the FP stand, the drawing amount in the SZ stand, and the pass line height of the auxiliary bottom roll. The tube forming apparatus according to claim 23,
The swivel unit in the FP stand is a tube forming device having a fin at the center of the inner surface of each hole die. The tube forming apparatus according to claim 23,
A pipe forming apparatus in which fins are omitted from each hole die of the swivel unit in the FP stand, and the inner surface of the FP stand is temporarily tacked on the inner surface of the open pipe. The tube forming apparatus according to claim 23,
An SZ stand consisting of upper and lower two-way rolls or upper and lower, left and right four rolls is arranged at the next stage of the FP stand, and further, both edges of the open pipe are externally welded while restraining the open pipe from the outer surface side. A pipe forming device that places a TW stand and welds both edges of the open pipe in-line on the outside. A die array in which a hole die with the forming hole mold facing outward is connected to an endless row is supported so as to be able to turn on an endless track, and a huge forming roll is assumed in a part of the hole shape in the turning direction. An SZ stand consisting of upper and lower two-way rolls or upper and lower and left and right four rolls is arranged at the next stage of the FP stand using a turning unit with a circular arc of radius as the upper unit and rolls as the lower unit and the side unit,
Further, in the next stage, a TW stand for restraining the open pipe from the outer surface side and welding the both edge portions of the open pipe to the outer surface is arranged, and the pipe welding apparatus for welding the both edges of the open pipe to the outer surface in-line. The pipe welding device according to claim 34, wherein
The swivel unit in the FP stand is a pipe welding device having a fin at the center of the inner surface of each hole die. The pipe welding apparatus according to claim 35, wherein
At the throttle position of the SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from inside the open pipe are arranged using a mandrel, and both edge portions of the open pipe are arranged. Pipe welding equipment for external surface welding in-line. The pipe welding device according to claim 34, wherein
The FP stand is a pipe welding device that is a composite SZ stand in which fins are omitted from each hole die of the swivel unit. The pipe welding apparatus according to claim 37,
A pair of upper and lower inner surface support rollers that contact and support the upper inner surface and lower inner surface of the open pipe from within the open pipe are arranged using a mandrel at the throttle position of the composite SZ stand, and both edges of the open pipe Pipe welding equipment that welds the outer surface inline. The pipe welding apparatus according to claim 37,
A pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe are arranged using a mandrel at the throttle position of the composite SZ stand, and further upstream of the pair. A pipe welding apparatus in which an inner surface supporting roller with fins for abutting and supporting the upper inner surface of an open pipe is arranged using a mandrel, and both edge portions of the open pipe are welded to the outer surface in-line. The pipe welding apparatus according to claim 37,
A mandrel is used for a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the roll type SZ stand arranged at the next stage of the composite type SZ stand. And a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe at the throttle position of the composite SZ stand, respectively, using a mandrel, Pipe welding equipment that welds both edges of an open pipe in-line to the outside. The pipe welding apparatus according to claim 37,
A mandrel is used for a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the roll type SZ stand arranged at the next stage of the composite type SZ stand. And a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and the lower inner surface of the open pipe from the inside of the open pipe at the throttle position of the composite SZ stand using a mandrel, Further, a pipe welding apparatus in which an inner surface supporting roller with fins for abutting and supporting the upper inner surface of the open pipe is arranged on the upstream side by using a mandrel, and both edge portions of the open pipe are externally welded in-line. The pipe welding apparatus according to claim 37,
In the composite SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe, respectively, at least the upper inner surface support roller is upstream of the throttle position of the composite SZ stand. Place it in a position that deviates,
A pipe welding device in which a welding torch for inner surface welding is arranged at the drawing position of the composite SZ stand, both edges of the open pipe are welded in-line on the inner surface, and then continuously welded on the outer surface. The pipe welding apparatus according to claim 37,
In the composite SZ stand, a pair of upper and lower inner surface support rollers for abutting and supporting the upper inner surface and lower inner surface of the open pipe from within the open pipe, respectively, at least the upper inner surface support roller is upstream of the throttle position of the composite SZ stand. Place it in a position that deviates,
On the further upstream side of the inner surface supporting roller for the upper inner surface, an inner surface supporting roller with fins for contacting and supporting the upper inner surface of the open pipe is disposed,
A welding device for pipes, in which a welding torch for inner surface welding is arranged at the drawing position of the composite type SZ stand, both edges of the open pipe are welded in-line on the inner surface, and then the outer surface is welded. The pipe welding apparatus according to claim 42 or 43,
A pipe welding device that omits the TW stand and welds both edges of the open pipe inline.

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