EP3225321B1 - A method of producing a steel pipe - Google Patents

A method of producing a steel pipe Download PDF

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Publication number
EP3225321B1
EP3225321B1 EP15863977.3A EP15863977A EP3225321B1 EP 3225321 B1 EP3225321 B1 EP 3225321B1 EP 15863977 A EP15863977 A EP 15863977A EP 3225321 B1 EP3225321 B1 EP 3225321B1
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EP
European Patent Office
Prior art keywords
bent portion
preformed body
bending
steel pipe
lightly
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EP15863977.3A
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German (de)
English (en)
French (fr)
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EP3225321A4 (en
EP3225321A1 (en
Inventor
Masayuki Horie
Yukuya TAMURA
Toshihiro Miwa
Junichi Tateno
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JFE Steel Corp
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JFE Steel Corp
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Publication of EP3225321A4 publication Critical patent/EP3225321A4/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/01—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments
    • B21D5/015—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments for making tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/01—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments

Definitions

  • the present invention relates to a method for producing a steel pipe according to the preamble of claim 1. Such a method is known from JP 2012 250 285 A .
  • the present invention relates in particular to a method suitable for producing a thick and large-diameter steel pipe used for a line pipe or the like.
  • UOE forming technique As a technique for producing a thick and large-diameter steel pipe used for a line pipe or the like, a so-called UOE forming technique is widely used which presses a steel plate having a predetermined length, width and plate thickness into a U-shape, press-forms the steel plate into an O-shape to make an open pipe, thereafter its gap portion is butt-jointed by welding, and enlarges its diameter (so-called pipe expansion) to further improve the roundness.
  • Patent Document 1 discloses a method of preliminarily forming a material in a C-shape forming process and a U-shape forming process, then performing an O-shape forming process thereon, so that a deformation mode of the material to be formed becomes fitting to dies at both top and bottom portion in the O-shape forming process.
  • Patent Document 2 discloses a method of changing a position of a butted part of a U-shaped steel plate to dies by performing a plurality of O-shape presses on the U-shaped steel plate and also rotating the U-shaped steel plate during the O-shape press
  • Patent Document 3 discloses a method of performing the O-shape press on a member formed into a U-shape by a U-shape press with an insert liner which is applied for larger outer diameter pipe to an intermediate outer diameter.
  • Patent Document 4 discloses a forming method in which a strain detector capable of detecting the inclination or distortion of a bending member mounted on a slide is disposed, the bending member is disposed in a tiltable or parallel-movable manner corresponding to the detection of the inclination or distortion by the strain detector, and the bending member is inclined or parallel moved to be subjected to press-forming so that an amount of distortion is smaller than an amount of inclination or an amount of distortion of the bending member when press-forming a material to be formed into a pipe shape.
  • Patent Document 5 discloses a method of forming a slit pipe equipped with a non-circular preform by performing the slight forming compared to other bending steps in at least one bending step of acting on the inner surface of the plate material on left and right with respect to a center defined by a longitudinal axis of an upper tool that enters a plate material to be progressively formed, and thereafter, forming a finished slit pipe by appropriately applying a pressing force acting on an area formed slightly in advance on both sides of the center from the outside to the non-circular preform.
  • Patent Document 6 discloses a method of forming a pipe with a closed slit portion, by applying the plastic deformation only to the flat portion of at least one location in the preformed body having a flat portion between at least two bent portions bent to a predetermined pipe curvature.
  • a circumferential length on a forming surface of the die is set to be substantially equal to the width size of a plate material (a raw plate), and the plate material is formed into a pipe shape by bringing a extending portion of the material into contact with a forming surface of the die during deformation of the O-shape press to adjust it into a shape of the forming surface of the die.
  • a contact portion with the die is increased, the pressing force is gradually increased, and there is a need for a large press machine.
  • Patent Documents 4, 5 and 6 although they do not accompany an increase in pressing force as in Patent Documents 1 to 3, since the material to be formed or the non-circular preform is separately formed on each of left and right sides, when the amount of deformation differs on the left and right sides, there is a risk of formation of a step difference (offset) in the gap portion or the slit portion serving as a welded portion. Further, in these methods, the deformation is locally concentrated when trying to deform a shape to a desired shape at one time, and there is a fear of worsening the roundness. Accordingly, deformations of several times are inevitable, and there is also a limit in efficient production.
  • the present invention is to provide a producing method of efficiently producing a steel pipe having high roundness without requiring an excessive bending force (load).
  • the present invention proposes as a solution a method of producing a steel pipe with the features of claim 1; i.e. subjecting a plate material which is bent at width end portion to at least one bending along its widthwise direction to provide a preformed body having a U-shaped cross-section, pressing the preformed body by applying a bending force to thereby form an open pipe with a gap portion in its longitudinal direction, and butt-joining end surfaces of the gap portion of the open pipe to each other, wherein a lightly-bent portion to which a slighter curvature is applied as compared to other regions or a non-bent portion in which the bending is omitted is provided in at least a part of the plate material in a process performing the bending on the plate material, and a bending-force is applied to a part spaced apart from the center of the lightly-bent portion or the non-bent portion by a distance within a range of W/4 ⁇ 0.07W in a width end portion direction of the plate material, where W is the
  • a pressing die with a pair of bending tools is used, wherein at least one of the bending tools has a circular arc surface having a width center that lies on an axis of symmetry of the press die, and a forming surface having an inclined surface which leads to each of both ends of the circular arc surface and is directed toward the forming center of the press die.
  • the circular arc surface preferably has a central angle of not less than 28°, an angle formed between the inclined surface and a straight line intersecting with a straight line passing through a widthwise center of the circular arc forming surface is preferably not less than 14°, and a surface having a radius of not more than 1.2 times the diameter of a steel pipe to be produced may be applied as the circular arc surface.
  • the lightly-bent portion or the non-bent portion is provided at a part spaced apart from a width end portion of the plate material by amount of W/4, and the preformed body having a U-shaped cross-section is pressed into an open pipe, the part is not restricted by the press die, and thus, it is possible to suppress an increase in forming reaction force.
  • a length of the lightly-bent portion or the non-bent portion along the widthwise direction of the plate material is not more than 10% of the plate width dimension, it is possible to obtain an open pipe having a small open amount of the butted portion, while maintaining the dimensional accuracy.
  • the preformed body is preferably supported at a part at least away from an extension line on which the bending force acts, and the pressing of the preformed body is started under the condition of ⁇ f > ⁇ s in which an opening angle of the preformed body defined based on the part supporting the preformed body is defined by ⁇ s, and an angle of the bending force is defined by ⁇ f, so that the lightly-bent portion or the non-bent portion is deformed so as to extend outward.
  • a press die provided with a forming surface not coming into contact with the lightly-bent portion or the non-bent portion is preferably used, such that it is possible to press the preformed body while decreasing the bending force.
  • the bending force is preferably simultaneously applied to parts (two locations) spaced apart from the center of the lightly-bent portion or the non-bent portion toward the width end of the plate material by an amount of W/4 at the time of pressing of the preformed body, such that an offset in which the end surfaces greatly differ in the gap portion is not formed.
  • the forming center of the press die used in the pressing of the preformed body preferably matches with the width center of the preformed body at the time of pressing of the preformed body, such that it is possible to evenly bend a portion corresponding to the width end of the plate material in the gap portion of the open pipe on the left and right sides, and a large offset is not formed in the gap portion.
  • the preformed body is preferably held in a U-shaped posture and is supported at its lowermost end (the center in the widthwise direction of the preformed body), such that it is possible to symmetrically deform the preformed body on the boundary of the center in the widthwise direction, and it is possible to obtain an open pipe with high roundness.
  • the press die is preferably constituted by a pair of bending members interposing the preformed body therebetween, and a forming surface having a cross-sectional shape which does not come into contact with the lightly-bent portion or the non-bent portion during pressing of the preformed body is formed in the bending member.
  • the forming reaction force is decreased, and it is possible to efficiently produce the steel pipe.
  • At least one of the bending members preferably has a circular arc surface having a width center matching an axis of symmetry of the press die, and a forming surface having a slope leading to each of both ends of the circular arc surface and directed toward the axis of symmetry of the press die, such that it is possible to obtain a steel pipe with high roundness without forming a step in the gap portion.
  • the central angle of the circular arc surface is set to not less than 28°, and the angle between the inclined surface and the straight line intersecting with a straight line passing through the widthwise center of the circular arc forming surface is set to not less than 14°, at the time of pressing of the preformed body, it is possible to reliably extend the lightly-bent portion or the non-bent portion toward the outside.
  • the lightly-bent portion or the non-bent portion is preferably not restricted by the forming surface of the press die by setting the circular arc surface to have the diameter of not more than 1.2 times the diameter of the steel pipe to be produced at the time of pressing of the preformed body, whereby the forming reaction force can be decreased.
  • FIGs. 1 and 2 are diagrams schematically illustrating a preferred punch and die and a preferred press die, respectively, that are used in the practice of the method of producing a steel pipe according to the present invention.
  • the punch and die shown in FIG. 1 is used when forming a plate material into a preformed body having a U-shaped cross-section by bending the plate material along its widthwise direction
  • the press die shown in FIG. 2 is used when forming the preformed body into an open pipe having a gap in the longitudinal direction by applying a bending force to the preformed body having the U-shaped cross-section.
  • Reference number 1 in FIG. 1 denotes a die disposed in a conveying path of the plate material S.
  • the die 1 is configured with a pair of left and right rod-like members la and lb that supports the plate material S at two locations along its feeding direction and enables a change in an interval e between the rod-like members la and lb depending on the size of the steel pipe to be produced.
  • reference number 2 denotes a punch which is movable in a direction of moving close to or away from the die 1.
  • the punch 2 includes a punch tip 2a having a downward convex forming surface that comes into direct contact with the plate material S to bend the plate material S into a concave shape, and a punch support 2b that is connected to the rear (upper end) of the punch tip 2a with the same width thereof to support the punch tip 2a.
  • reference number 3 denotes a roller for forming the conveying path of the plate material S.
  • reference number 4 in FIG. 2 denotes an upper die (bending tool)
  • reference number 5 denotes a lower die which mates with the upper die 4 (bending tool).
  • the preformed body (which has a U-shaped cross-section) formed by the die 1 and the punch 2 is located between the upper die 4 and the lower die 5, and a bending force is applied to the preformed body to form an open pipe.
  • the upper die 4 may have a circular arc surface 4a having a width center that matches the forming center (an axis of symmetry) thereof, and a forming surface (inclined surface) 4b connected to each of both ends of the circular arc surface 4a and having a slope directed toward the forming center side of the press die.
  • the lower die 5 may have a forming surface that does not come into contact with the lightly-bent portion or the non-bent portion during pressing of the preformed body.
  • the upper die 4 may have a press die having a forming surface that does not come into contact with the lightly-bent portion or the non-bent portion during pressing of the preformed body.
  • the lower die 5 it is possible to apply one that includes a circular arc surface having a width center matching the forming center (an axis of symmetry) thereof, and an inclined surface which is connected to each of both ends of the circular arc surface and is directed toward the forming center side of the press die.
  • first, end bending (also referred to as crimping) is performed on the width end portion of the plate material S.
  • the end bending is performed on a plate width end portion that is harder to bend as compared to the case of performing the bending using the die 1 and the punch 2, and it is possible to obtain a steel pipe in which high roundness is secured by providing an end bending portion by this forming.
  • the plate material S provided with the end bending portion is mounted on the die 1 as shown FIG. 1 , and bending (3-point bending) is applied over the entire region as illustrated in FIG. 3 , while intermittently feeding the plate material S by a predetermined feed amount, thereby forming the plate material into a preformed body which has a U-shaped cross-section as a whole.
  • a lightly-bent portion to which a slighter curvature is applied as compared to other regions or a non-bent portion P in which the bending is omitted is provided as shown in Fig. 4 by enlarging its cross-section.
  • the lightly-bent portion P can be provided by pressing while decreasing the bending amount applied by the punch 2, and the non-bent portion P can be provided by omitting the bending of the punch 2 while increasing the feeding of the plate material S.
  • FIG. 3 specifically illustrates an example of a case of performing the bending and the feeding of the plate material S on the plate material S previously subjected to edge bending, sequentially from the top to the bottom of the left column, from the top to the bottom of the center column, and further from the top to the bottom of the right column, and the arrow assigned to each of the punch 2 and the plate material S in FIG. 3 illustrates the moving direction of the punch 2 and the plate material S at each stage.
  • the punch 2 which performs bending on the plate material S
  • the preformed body S 1 is pressed using the upper die 4 and the lower die 5 illustrated in FIG. 2 .
  • the preformed body S 1 is held in a U-shaped posture so that an opening portion faces upward, and is located on the lower die 5 so that its lowest end, that is, the center in the widthwise direction becomes a support part.
  • the bending force is simultaneously applied to two locations of the width end portions of the plate material S which are parts spaced apart from the lightly-bent portion or the non-bent portion P toward the width end by amount of W/4 by the upper die 4.
  • the preformed body S 1 is supported on the lower die 5 at a part at least away from the line of action of the bending force, and the lightly-bent portion or the non-bent portion P is not constrained by the press die, the preformed body S 1 is formed into a tubular shape without requiring excessive bending force.
  • the forming surface is a circular arc surface having a concave shape, it can be achieved by setting a larger diameter than the diameter of the steel pipe to be produced. Further, the forming surface may be a flat surface with which the preformed body S 1 linearly comes into contact.
  • the bending force is applied at least to a part away from the center of the lightly-bent portion or the non-bent portion P by amount of W/4, the reason of which is as follows.
  • the bending moment (M) when the whole preformed body S 1 has a circular shape is F ⁇ r ⁇ cos ⁇ (F: bending force, r: radius of circle) at a position of an angle ⁇ from the position applied with the bending force, and becomes maximum at the position away from the position applied with the bending force by 90°, and the deformation also becomes maximum. Therefore, by applying the bending force to the position away from the center of the lightly-bent portion or the non-bent portion P by 90°, that is, 1/4 of the entire circumference, the lightly-bent portion or the non-bent portion P is effectively deformed.
  • the bending moment is maximum at the position away from the applying position of the bending force by 90° and it becomes smaller as going away from this position.
  • the bending force is preferably applied by amount of W/4 ⁇ 0.07 W.
  • the center of the lightly-bent portion or the non-bent portion P is provided in a part including a part away from the width end portion of the plate material S by amount of W/4, the reason of which is as follows.
  • the bending force is preferably applied to a position apart from the center of the lightly-bent portion or the non-bent portion P in the width end direction of the plate material by amount of W/4, since its shape is changed at the step of forming the preformed body S 1 into an open pipe, a contact position with the upper die 4 is changed, and the position applied with the bending force is also changed.
  • the lightly-bent portion or the non-bent portion P is provided at a position spaced apart from the width end portion of the plate material S by amount of W/4, a position applied with the bending force is always a width end portion of the plate material S, and the lightly-bent portion or the non-bent portion P are most deformed.
  • the lightly-bent portion or the non-bent portion P is preferably provided in a range of W/4 ⁇ 0.07W from the position applied with the bending force, that is, the width end portion of the plate material.
  • the length L (see FIG. 4 ) along the widthwise direction of the plate material S of the lightly-bent portion or the non-bent portion P is preferably set to not more than 10% of the plate width.
  • the bending moment (M) when the whole preformed body S 1 becomes a circular shape is F ⁇ r ⁇ cos ⁇ (F: bending force, r: radius of circle) at the position of the angle ⁇ from the position applied with the bending force, and bending moment becomes maximum at the position spaced apart from the position applied with the bending force by 90°, and the amount of deformation is also the maximum.
  • the amount of deformation is not uniform in the lightly-bent portion and the non-bent portion P. Therefore, the obtained open pipe has irregularities, rather than a uniform circular arc.
  • a relation between a value obtained by dividing the length L of the lightly-bent portion or the non-bent portion P of the shaped body S 1 having the U-shaped cross-section by the plate width and a value obtained by dividing an irregularity amount by the outer diameter of the tubular material is investigated.
  • the irregularity amount is also larger.
  • the tubular material having the outer diameter of 559 mm when the length of the lightly-bent portion or the non-bent portion P exceeds 10% of the plate width, the irregularity amount exceeds 1.5% of the outer diameter.
  • the length L of the lightly-bent portion or the non-bent portion P along the widthwise direction of the plate material S is preferably set to not more than 10% of the plate width. Furthermore, in order to provide sufficient deformation to the lightly-bent portion or the non-bent portion P, the length L is preferably in the range of W/4 ⁇ 0.07 W from the position applied with the bending force.
  • FIG. 8 is a graph showing a relation between the interval (opening of U-shaped cross-section) of the opening portion of the preformed body S 1 having a U-shaped cross-section and the length L of the lightly-bent portion or the non-bent portion P.
  • the dimensional accuracy is better as the length L of the lightly-bent portion or the non-bent portion P becomes smaller, since the opening interval of the preformed body S 1 also becomes smaller, when the opening interval is smaller than the width of the punch 2, it is not possible to raise the punch 2 after the final bending (the last state of FIG. 3 ), and it is difficult to detach the preformed body S 1 from the press machine. Therefore, the lower limit of the length L is set depending on the size of the applied device or the steel pipe to be produced. For example, when a pipe having an outer diameter of 559 mm is produced by a press machine having the punch 2 having a width of 150 mm, L/W is required to be not less than 0.05.
  • the opening angle defined based on the part on which the preformed body S 1 is supported is defined as ⁇ s
  • the angle of the bending force applied to the preformed body S 1 is defined as ⁇ f
  • the pressing of the preformed body S 1 is started under a condition of ⁇ f > ⁇ s.
  • the part in which the preformed body S 1 is supported by satisfying this condition is not existent on the line of action of the bending force, and the lightly-bent portion or the non-bent portion P can reliably extend toward the outside with relatively small bending force.
  • the opening angle ⁇ s of the preformed body S 1 is defined as an angle formed between the reference line and the straight line r connecting the widthwise center (W/2) of the preformed body and the widthwise end portion of the preformed body S 1 (see FIG. 5 ).
  • the forming surface of the upper die 4 is configured to include a circular arc surface 4a having a width center that matches the forming center O of the press die, and a pair of forming surfaces 4b which is connected to each of both ends of the circular arc surface 4a and is directed toward the forming center O side of the press die, the forming surfaces 4b may be a straight inclined surface or a curved inclined surface.
  • the central angle ⁇ c of the circular arc surface 4a is set in the range of not less than 28°, and the forming surface 4b is deformed so as to reliably extend the lightly-bent portion or the non-bent portion P to the outside at the time of pressing of the preformed body S 1 . Therefore, it is possible to set the angle ⁇ d formed with the straight line intersecting with the straight line passing through the widthwise center of the circular arc surface 4a in the range of not less than 14° (see FIG. 2 ).
  • FIG. 10 illustrates the result of a relation between the angle 0d of the forming surface 4b of the upper die 4 and the direction ⁇ f (angle of the bending force) of force obtained for a general lubrication state (the case of the friction coefficient of 0.1).
  • the minimum value of L/W is 0.05
  • the opening angle ⁇ s of the preformed body S 1 is 9°.
  • the press die angle ⁇ d is not less than 14°
  • the direction ⁇ f of power is larger than the opening angle ⁇ s of the preformed body S 1 .
  • the opening angle ⁇ s of the preformed body S 1 is geometrically determined by the ratio of the length L and the plate width W of the lightly-bent portion or the non-bent portion P, and when the L/W increases, the opening angle ⁇ s of the preformed body S 1 also increases. Thus, in some cases, it may be necessary to further increase the central angle 0c of the circular arc surface 4a of the upper die 4.
  • the opening portion of the press die becomes smaller than the maximum width of the preformed body S 1 having a U-shaped cross-section, and as illustrated in FIG. 11 , since the upper die 4 may bite into the preformed body S 1 and scratch it, its upper limit is determined depending on a maximum width of the preformed body S 1 .
  • the circular arc surface 4a of the upper die 4 may be set to the radius of not more than 1.2 times the diameter of the steel pipe to be produced. The reason is as follows.
  • FIG. 13 shows a relation between (the radius of circular arc surface 4a of the upper die 4/ the radius of the steel pipe) and the index (residual index) in which the lightly-bent portion or the non-bent portion P is left (not bent to circular) as it is.
  • the index residual index
  • the radius of the circular arc surface 4a of the upper die 4 is desirably suppressed to not more than 1.2 times the radius of the steel pipe to be produced.
  • FIG. 14 is a graph showing a relation between (the radius of the circular arc surface 5a of the lower die 5/the radius of the steel pipe) and (the forming load/the load when the lightly-bent portion or the non-bent portion P is freely bent).
  • the radius of the circular arc surface 5a of the lower die 5 is small, since the lightly-bent portion or the non-bent portion P is restricted by the press die during forming of the preformed body S 1 , the forming load increases.
  • the radius of the circular arc surface 5a of the lower die 5 is less than 1.05 times the diameter of the steel pipe to be produced, the forming load rapidly increases.
  • the radius of the circular arc surface 5a of the lower die 5 is desirably not less than 1.05 times the diameter of the steel pipe to be produced.
  • the radius of the circular arc surface 5a of the lower die 5 is set to not less than 1.07 times the diameter of the steel pipe to be produced, it can be suppressed to not more than twice of the load applied when forming the preformed body S 1 in a non-restriction state.
  • the forming surface (inclined surface) 4b is made up of a circular arc surface 4a and the forming surface (inclined surface) 4b is adopted as the upper die 4, as long as it is possible to satisfy the condition ⁇ s > ⁇ f at the time of starting of pressing
  • a press die equipped with a forming surface formed with the circular arc surface 5a such as the lower die 5 may be used, and is not limited to the illustrated configuration.
  • the lower die 5 it is possible to use one such as die 1 illustrated in FIG. 1 which supports the preformed body S 1 at two points or a roller-type die. Even when using the die, since the lightly-bent portion or the non-bent portion P is not restricted by the forming surface of the press die during pressing, the preformed body S 1 can be formed into a tubular shape with a relatively small bending force.
  • the welding machine for example, a welding machine made up of three kinds of welding machines, such as a tack welding machine, an inner surface welding machine and an outer surface welding machine, is applied.
  • the tack welding machine continuously brings the butted surfaces into close contact with each other at the appropriate positional relation by cage rolls, and welds the close-contact portions over its entire length.
  • the tack pipe is welded (submerged arc welding) from the inner surface of the butted portion by the inner surface welding machine, and is further welded (submerged arc welding) from the outer surface of the butted portion by the outer surface welding machine.
  • the positional relation between the welding machine (the joining means) and the press die (the upper die 4 and the lower die 5) for pressing the preformed body S 1 is not particularly limited, and can be arbitrarily changed.
  • the material is placed on a die in which an interval of a rod-like member is set to 450 mm, and bending of the three-point bending is performed from the position of 1120 mm from the width center of the plate material, with a plate material feeding pitch of 224 mm and 11 bending times (five times from the paper right end, and five times from the left end) by a punch having a forming surface of a radius of 308 mm.
  • the bending amount is set to an amount in which the punch tip reaches a position of 15.8 mm from the line connecting the uppermost part of the rod-like member, and bending is performed by 30° for a time.
  • the bending is not performed, and the non-bent portion is formed at the position of 571 to 795 mm.
  • the steel pipe can be obtained in which the opening amount in the gap portion of the open pipe is 21 mm, the amount of offset after welding (steel pipe) is 0.1 mm, the roundness is 5.2 mm and a difference to an outer diameter of 91.44 cm (36 inches) is only 0.6%.
  • Example 1 in order to form a steel pipe with a diameter of 91.44 cm (36 inches) using a line pipe steel plate(API grade X60) having a thickness of 38.1 mm and a width of 2711 mm, the material is placed on a die in which an interval of a rod-like member is set to 450 mm, and bending of the three-point bending is performed by 30° for a time, from the position of 1120 mm from the width center of the plate material, with a plate material feeding pitch of 224 mm and 11 bending times (five times from the paper right end, and five times from the left end) by a punch having a forming surface of a radius of 308 mm.
  • the bending amount is set to an amount in which the punch tip reaches a position of 15.8 mm from the line connecting the uppermost part of the rod-like member, and bending is performed by 30° for a time.
  • the lightly-bent portion is formed at the position of 571 to 795 mm, while decreasing the bending amount to 8.8 mm and performing the bending of 10°.
  • the steel pipe can be obtained in which the opening amount in the gap portion of the open pipe is 16 mm, the amount of offset after welding (in steel pipe) is 0.1 mm, the roundness is 8.2 mm, and a difference to an outer diameter of 91.44 cm (36 inches) is only about 0.9%.
  • the material is placed on the die in which the interval of the rod-like members is set to 500 mm, and bending of the three-point bending is performed by a punch having a forming surface with a radius of 360 mm, and a preformed body having a U-shaped cross-section with different position and length of the non-bent portion from the width end portion is prepared.
  • the lower die having a concave circular arc surface having a radius R: 609.6 mm is installed on the rod-like member, and the preformed body having the U-shaped cross-section obtained by bending is pressed from the outside into an open pipe until an inter-apex distance (the apex of the R part is the uppermost part of the circular arc surface in the upper die, and the lowermost part of the circular arc surface in the lower die) of the R part of the press die reaches 1027 mm.
  • the material is placed on the die in which the interval of the rod-like members is set to 500 mm, and bending of the three-point bending is performed by a punch having a forming surface with a radius of 360 mm, and a preformed body having a U-shaped cross-section with different position and length of the non-bent portion from the width end portion is prepared.
  • the material is placed on the die in which the interval of the rod-like members is set to 400 mm, and bending of the three-point bending is performed by a punch having a forming surface with a radius of 188 mm, and a preformed body having a U-shaped cross-section with different position and length of the non-bent portion from the width end portion is prepared.
  • a lower die having a concave circular arc surface having a radius R: 330.2 mm is installed on the rod-like member, and the preformed body having the U-shaped cross-section obtained by bending is pressed from the outside into an open pipe, until an inter-apex distance (the apex of the R part is the uppermost part of the circular arc surface in the upper die, and the lowermost part of the circular arc surface in the lower die) of the R part of the press die reaches 538 mm,
  • the bending force becomes smaller.
  • the non-bent portion in the range of 0.28 to 0.19 from the plate width end portion, the satisfactory roundness is obtained, but in No. 11 in which the non-bent portion is close to the plate width end portion, the roundness is 10.6 mm which exceeds 1.5% of the product diameter.
  • the roundness is 11.2 mm which exceeds 1.5% of the product diameter.
  • the material is placed on the die in which the interval of the rod-like members is set to 400 mm, and bending of the three-point bending is performed by a punch having a forming surface with a radius of 188 mm, and a preformed body having a U-shaped cross-section with different position and length of the non-bent portion from the width end portion is prepared.
  • the material is placed on the die in which the interval of the rod-like members is set to 450 mm, and bending of the three-point bending is performed by a punch having a forming surface with a radius of 308 mm, and a preformed body having a U-shaped cross section provided with non-bent portions of the length of 109 mm and 224 mm around the position of 683 mm from the plate width end portion is prepared.
  • the opening amount is also small and the roundness is also good. Meanwhile, in Nos. 1, 2 and 4 of ⁇ f ⁇ ⁇ s, the opening amount is large, and in Nos. 1 and 4, the opening amount is too large to perform the welding. In addition, although the welding can be performed in No. 2, the roundness is 15.7 mm which exceeds 1.5% of the product diameter.
  • Table 6 describes the results together with the outer diameter of the steel pipe, and the ratio of the radius of the upper die to the outer radius of the steel pipe.
  • Table 6 No Outer diameter of steel pipe [mm] Radius of upper die/ outer radius of steel pipe Roundness [mm] Amount of offset [mm] 1 965.2 0.95 5.7 1.0 2 914.4 1.00 5.2 0.2 3 863.6 1.06 6.2 0.1 4 812.8 1.13 8.3 0.2 5 762.0 1.20 10.2 0.3 6 711.2 1.29 17.2 0.2
  • the material is placed on the die in which the interval of the rod-like members is set to 450 mm, and bending of the three-point 25 bending is performed by a punch having a forming surface with a radius of 308 mm, and a preformed body having a U-shaped cross section provided with a non-bent portion of the length of 224 mm around the position of 683 mm from the plate width end portion is prepared.
  • Table 7 describes a relation among deformation of the lower die, a ratio to the outer radius of the steel pipe, and the bending force.
  • Table 7 No Radius of lower die [mm] Radius of lower die / outer radius of steel pipe Load [MN] 1 482.6 1.06 75 2 508.0 1.11 50 3 533.4 1.17 35 4 558.8 1.22 35
EP15863977.3A 2014-11-25 2015-11-12 A method of producing a steel pipe Active EP3225321B1 (en)

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PCT/JP2015/081818 WO2016084607A1 (ja) 2014-11-25 2015-11-12 鋼管の製造方法及びその方法に使用するプレス金型

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JP6566231B1 (ja) * 2018-03-30 2019-08-28 Ｊｆｅスチール株式会社 鋼板の端曲げ方法および装置並びに鋼管の製造方法および設備
DE102018211311B4 (de) * 2018-07-09 2020-03-26 Sms Group Gmbh Erweiterte Regelung JCO-Formpresse
CN108994120A (zh) * 2018-08-01 2018-12-14 上海锆卓船舶设计有限公司 适用超高强度、超厚钢板的小直径圆筒的卷制方法及系统
RU2769596C1 (ru) * 2018-09-14 2022-04-04 ДжФЕ СТИЛ КОРПОРЕЙШН Способ изготовления стальной трубы и матрица
JP6846761B2 (ja) * 2018-10-19 2021-03-24 フタバ産業株式会社 プレス装置、及び楕円筒状部材の製造方法
CN109513763B (zh) * 2019-01-14 2024-02-20 廊坊中德汽车座椅制造有限公司 一种制造汽车座椅靠背架u型管的方法
JP6966492B2 (ja) * 2019-02-04 2021-11-17 フタバ産業株式会社 パイプの製造方法
JP7381010B2 (ja) 2019-10-03 2023-11-15 株式会社キーレックス 金属管成形装置及び金属管成形方法
WO2022009575A1 (ja) 2020-07-10 2022-01-13 Ｊｆｅスチール株式会社 鋼管の真円度予測モデルの生成方法、鋼管の真円度予測方法、鋼管の真円度制御方法、鋼管の製造方法、及び鋼管の真円度予測装置
WO2022009576A1 (ja) 2020-07-10 2022-01-13 Ｊｆｅスチール株式会社 鋼管の真円度予測方法、鋼管の真円度制御方法、鋼管の製造方法、鋼管の真円度予測モデルの生成方法、及び鋼管の真円度予測装置
JP7211461B1 (ja) 2021-09-03 2023-01-24 Ｊｆｅスチール株式会社 金属材料の引張圧縮反転負荷挙動予測方法

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JPWO2016084607A1 (ja) 2017-04-27
KR20170070155A (ko) 2017-06-21
BR112017010436A2 (pt) 2017-12-26
CN107000012B (zh) 2019-08-27
CA2967914A1 (en) 2016-06-02
WO2016084607A1 (ja) 2016-06-02
EP3225321A4 (en) 2017-12-27
BR112017010436B1 (pt) 2021-10-26
RU2663674C1 (ru) 2018-08-08
EP3225321A1 (en) 2017-10-04
CN107000012A (zh) 2017-08-01
CA2967914C (en) 2020-03-24

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