EP3851220A1 - Procédé de fabrication de tuyau en acier et matrice de presse - Google Patents

Procédé de fabrication de tuyau en acier et matrice de presse Download PDF

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Publication number
EP3851220A1
EP3851220A1 EP18933413.9A EP18933413A EP3851220A1 EP 3851220 A1 EP3851220 A1 EP 3851220A1 EP 18933413 A EP18933413 A EP 18933413A EP 3851220 A1 EP3851220 A1 EP 3851220A1
Authority
EP
European Patent Office
Prior art keywords
preform
die
steel pipe
pressing
arc
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP18933413.9A
Other languages
German (de)
English (en)
Other versions
EP3851220A4 (fr
Inventor
Masayuki Horie
Kosuke HINATA
Tomohiro Kawano
Yukuya TAMURA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
JFE Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JFE Steel Corp filed Critical JFE Steel Corp
Publication of EP3851220A1 publication Critical patent/EP3851220A1/fr
Publication of EP3851220A4 publication Critical patent/EP3851220A4/fr
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/08—Making tubes with welded or soldered seams
    • B21C37/0815—Making tubes with welded or soldered seams without continuous longitudinal movement of the sheet during the bending operation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/08—Making tubes with welded or soldered seams
    • 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
    • B21D3/00—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts
    • B21D3/16—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts of specific articles made from metal rods, tubes, or profiles, e.g. crankshafts, by specially adapted methods or means
    • 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
    • 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

Definitions

  • the present invention relates to a method of manufacturing a steel pipe and a press die for use in the method of manufacturing a steel pipe.
  • UOE forming techniques are widely used to form steel pipes.
  • a steel plate is first press-bent into a U shape and then pressed into an O shape to form an open pipe, which is a tubular body having a seam gap portion between plate width ends opposed to each other in a circumferential direction.
  • the seam gap portion of the open pipe is butted and joined by welding to form a steel pipe, which is then expanded such that the diameter of the steel pipe is increased.
  • the UOE forming technique requires a high press force in the process of pressing a steel plate into a U shape or an O shape to form an open pipe and inevitably requires the use of a large-scale press machine.
  • a technique for forming an open pipe with a reduced press force for example, a press-bending process is in practical use, in which the edge portions in the width direction of a steel plate are bent to produce edge bent portions, and thereafter three-point press bending is performed multiple times with a punch supported on a punch support and a die to shape the steel plate into an approximately circular shape.
  • the open amount of the seam gap portion of the open pipe formed by the press bending process is larger than the width of the punch support. If the open amount is too large, the force required for butting the plate width ends opposed to each other and closing the seam gap portion is increased in order to weld the seam gap portion. A larger facility is then required for closing the seam gap portion.
  • the welded portion receives a force caused by springback to open the seam gap portion and tends to suffer a weld defect. If the force is too large, the welded portion is broken.
  • Patent Literature 1 discloses a technique for reducing the open amount of the seam gap portion of an open pipe by providing a pivotable coupling portion between the punch front end and the punch support to reduce the width of the punch support.
  • Patent Literature 2 discloses a technique for reducing the open amount of the seam gap portion of an open pipe by providing gap holding means for restricting movement of a plate material in a direction orthogonal to the punch moving direction, and applying a large press in the final bending without the plate width end portions coming into contact with the punch support.
  • Patent Literature 3 discloses a technique for reducing the open amount of the seam gap portion of an open pipe by measuring the gap between the plate width end portion and the punch support after the final pressing-down process and minimizing the gap.
  • Patent Literature 4 discloses a technique for reducing the open amount of the seam gap portion of an open pipe irrespective of variation in shape produced in the press bending process, in which the amount of pressing-down by the punch in a final step is determined based on the point of time when the distance between the plate width ends becomes a predetermined value at the time of pressing-down in the final bending process.
  • Patent Literatures 1 to 4 fail to reduce the open amount of the seam gap portion of an open pipe to a width smaller than the width of the punch support. Then, the techniques for reducing the open amount of the seam gap portion by additionally processing the open pipe after press bending are disclosed in Patent Literatures 5 to 9.
  • Patent Literature 5 discloses a technique of forming a pipe with a smaller load by hot-pressing a steel pipe after press bending.
  • Patent Literature 6 discloses a technique of pressing, in which a distortion detector is disposed to detect a tilt or distortion of a pressing member attached to a slide, the pressing member is disposed so as to be able to tilt or translate in response to detection of a tilt or distortion by the distortion detector, and when the blank material is pressed into a pipe shape, the pressing member is tilted or translated for the amount of tilt or inclination of the pressing member so as to reduce the amount of distortion.
  • Patent Literature 7 discloses a technique in which a slit tube having a non-circular preform is formed by shaping slightly, compared to other bending steps, in at least one bending step acting on the inner face of a plate material on the right and left sides with respect to the center defined by the longitudinal axis line of an upper-side tool going into the plate material progressively shaped, and the slit tube is then completed by properly in each case adding a pressing force acting on the areas previously shaped slightly at both sides of the center to the noncircular preform from outside.
  • Patent Literature 8 discloses a technique in which, in a blank having a flat portion between portions bent into at least two pipe curvatures, plastic deformation is applied to at least one flat portion into a predetermined curvature to form a pipe with a closed slit portion.
  • Patent Literature 9 discloses a method of forming a pipe with a closed slit portion. The method includes providing a lightly bent portion with a curvature slighter than other regions or providing a non-bent portion in which bending is omitted, to form a preformed body, and applying a bending force without constraining the lightly bent portion or the non-bent portion, in pressing the preformed body into an open pipe. In applying the bending force, it is recommended that the preformed body is held in a die in a U-shaped posture with its opening portion facing upward, and is supported at its lowermost end.
  • Patent Literatures 10 and 11 disclose a method of manufacturing a UOE pipe having a product diameter in which the outer diameter of the product pipe is different from the diameter of an inner surface of an O-press die.
  • the die disclosed in Patent Literature 10 is shaped such that only a part of the ellipse shape of the inner surface of the upper/lower die is notched.
  • FIG. 3(a) and FIG. 4(a) of Patent Literature 10 illustrating the effect of the die an O pipe is in contact with the entire inner surface of the O-press die.
  • Patent Literature 11 discloses a method using a die that has an inner surface having an arc with a radius larger than a product outer diameter and has an end surface ground in advance to provide a sufficiently large gap.
  • the formed pipe is rotated by about 90 [°] and O-pressing is performed again to form a circular shape.
  • the steel pipe is in intimate contact with the entire surface of the die.
  • Patent Literature 5 incurs a significant cost increase if thermal energy consumption involved in heating is included. Moreover, in this technique, if a plate material produced through a thermomechanical processing step is used for achieving strength, toughness, and weldability, the characteristics of the material may be impaired.
  • the blank material or the noncircular preform is formed separately on the right side and the left side. If the amount of deformation is different between the right and the left, a level difference (misalignment) may be produced at the seam gap portion or the slit portion serving as a welded portion. In these techniques, deformation into a desired shape in a single step causes local concentration of deformation, which may deteriorate the roundness of the steel pipe.
  • Patent Literature 9 since the radius of the lower die is larger than the pipe outer diameter, the lowermost portion of the preformed body in a U-shaped posture is bent back, causing a deformation that opens the gap portion. This may prevent reduction of the gap of the slit portion.
  • the techniques disclosed in Patent Literatures 10 and 11 involve pressing in a state in which the O pipe is in intimate contact with the entire surface of the die, and require a high press force as described above and still inevitably require a large-scale press machine.
  • An object of the present invention is to provide a method of manufacturing a steel pipe for efficiently forming a steel pipe with high roundness and a press die.
  • a method of manufacturing a steel pipe includes: performing bending three or more times on a plate material along a width direction, the plate material being subjected to edge bending at both ends in the width direction, to form a preform having a U-shaped cross section; pressing the preform to form an open pipe, the open pipe being a tubular body having a seam gap portion in a longitudinal direction; and joining the seam gap portion to form a steel pipe, wherein when a width of the plate material before the edge bending is a plate width W, the preform has a lightly bent portion or an unbent portion of which center is positioned at a point away from a plate width end by W/4, the lightly bent portion having a small curvature compared with other regions, the unbent portion being not subjected to bending, and the pressing is performed to form the open pipe into a shape such that a range of 20 [%] or more of the plate width W of which center is positioned at a lowermost portion of the
  • the second die when the preform is placed on a second die of a pair of dies such that a first die of the pair of dies is opposed to a U-shaped open side of the preform, and the preform is pressed while the preform is held between the pair of dies, the second die includes a pressing surface in such a manner that: in a state in which the preform is placed on the second die, the pressing surface is not in contact with the preform, excluding a range formed into a shape inscribed in an arc with a diameter equal or substantially equal to an outer diameter of the steel plate, with respect to the lowermost portion of the U-shaped cross section; and in a state in which pressing is completed, a part of the second die is not in contact with the open pipe, and the first die includes a pressing surface in such a manner that: in a state in which the preform is placed on the second die, the pressing surface is not in contact with the preform; and in a state in which pressing is completed
  • pressing is performed using a die having a radius of an arc portion within a range of ⁇ 3.5 [%] with respect to a radius corresponding to an outer radius of the steel plate.
  • a center of a press die for use in pressing of the preform matches a center in a width direction of the preform.
  • the preform is held in a U-shaped posture with a U-shaped open side facing upward.
  • a press die for use in the method of manufacturing a steel pipe according to the present invention includes: a pair of dies which are a pair of pressing bodies for holding the preform; and an arc portion formed in a surface of each die in contact with the preform such that an arc center is located at a position coincident with a bending center of the die, the arc portion having a radius within a range of ⁇ 3.5 [%] with respect to a radius corresponding to an outer radius of the steel pipe, wherein the arc portion in each die has a central angle of 70 degrees or larger, and a total angle of the central angles of the arc portions of both dies is smaller than 360 degrees.
  • the central angles of the arc portions of both dies are equal to each other.
  • each die includes linear portions or small-curvature arc portions having a curvature smaller than the arc portion, the linear portions or the small-curvature arc portions being connected to both ends of the arc portion in an arc direction.
  • the press die according to the present invention is used.
  • the method of manufacturing a steel pipe and press die according to the present invention achieve the effect of efficiently forming a steel pipe with high roundness.
  • FIG. 1 is an external perspective view of a die 1 and a punch 2 for use in forming a preform having a U-shaped cross section through a press bending process according to the present embodiment.
  • the die 1 is disposed in a conveyance path including a plurality of conveyance rollers 3 for a plate material S and includes a pair of left and right rod-shaped members 1a and 1b for supporting the plate material S at two points along the plate material conveyance direction.
  • a distance e between the rod-shaped members 1a and 1b in the plate material conveyance direction can be changed according to the size of a finished steel pipe.
  • the punch 2 is movable in a direction closer to or away from the die 1 and includes a downwardly projecting punch front end 2a for pressing a plate material S and a punch support 2b continuous to the back surface (upper end surface) of the punch front end 2a with the same width for supporting the punch front end 2a.
  • the punch support 2b has an upper end coupled to not-illustrated driving means. The driving means applies a pressing force to the punch front end 2a.
  • FIG. 2 illustrates the procedure for forming a preform S 1 having a U-shaped cross section through a press bending process.
  • This procedure specifically illustrates an example in which a plate material S subjected to edge bending in advance is bent and the plate material S is fed in order from the top to the bottom in the left column in FIG. 2 , then from the top to the bottom in the middle column in FIG. 2 , and finally to the right column in FIG. 2 .
  • the arrows given to the punch 2 and the plate material S in FIG. 2 indicate the direction in which the punch 2 or the plate material S moves in each stage.
  • edge bending is performed on the plate material S in advance. This edge bending is performed for a plate width end portion, which is relatively difficult to bend, compared with the bending performed on the plate material S using the die 1 and the punch 2.
  • edge bent portions are provided at the plate width end portions of the plate material S by the edge bending, a steel plate with high roundness can be easily obtained, compared with when no edge bent portion is provided.
  • the roundness of a steel pipe is an index representing how close to a circle the cross-sectional shape of the steel pipe is, and is a value indicated by a ratio obtained by dividing the difference between the maximum and the minimum of the amount of variation from an approximate arc on the entire circumference of a steel pipe by the steel pipe diameter.
  • a steel pipe having an outside diameter D is divided into 8 equal parts, 12 equal parts, 16 equal parts, or 24 equal parts in the circumferential direction of the pipe at any given pipe length, and the outside diameters at opposed positions are measured.
  • the roundness [%] is defined by ⁇ (D max -D min )/D ⁇ 100. As the roundness is closer to zero, the cross-sectional shape of the steel pipe is closer to a perfect circle.
  • the plate material S provided with the edge bent portions is placed on the die 1 illustrated in FIG. 1 . While the plate material S is intermittently conveyed at a predetermined feeding amount, bending is performed three or more times along the width direction of the plate material S through the procedure illustrated in FIG. 2 to form a preform S 1 having a U-shaped cross section as a whole.
  • FIG. 3 is a cross-sectional view of the preform S 1 having a U-shaped cross section.
  • the width of the plate material S before edge bending is a plate width W
  • an unbent portion P not subjected to bending is provided at a part of the preform S 1 , in particular, such that a center of the unbent portion P is positioned at a W/4 portion that is a section W/4 away from each of the plate width ends.
  • This unbent portion P can be provided by increasing the feeding amount of the plate material S and omitting the pressing by the punch 2.
  • a lightly bent portion having a curvature smaller than other portions may be provided instead of the unbent portion P.
  • unbent portion P may read “lightly bent portion", if necessary.
  • the lightly bent portion can be provided by applying a smaller amount of pressing by the punch 2 than on other portions.
  • the punch 2 illustrated in FIG. 1 and FIG. 2 has an I shape in which the width of the punch front end 2a in the plate material conveyance direction is equal to the width of the punch support 2b in the plate material conveyance direction.
  • the shape of the punch 2 is not limited to this.
  • a punch 2 having an approximately inverse T shape may be used, in which the width of the punch front end 2a in the plate material conveyance direction is larger than the width of the punch support 2b in the plate material conveyance direction. If the width of the punch support 2b in the plate material conveyance direction is the same, the punch 2 having an approximately inverse T shape can press a larger area of the plate material S in a single press, compared with the punch 2 having an I shape, thereby reducing the number of times of pressing.
  • O-pressing is performed to press-bend the preform S 1 into an O shape using a press die that is a pair of dies including an upper die 4 and a lower die 5 as illustrated in FIG. 4 , thereby forming an open pipe S 2 , which is a tubular body having a seam gap portion G between the plate width end portions opposed to each other in the circumferential direction.
  • the preform S 1 is installed in the lower die 5 such that the upper die 4 and the U-shaped open side of the preform S 1 are opposed to each other (such that the U-shaped open side of the preform S 1 faces upward), and the preform S 1 is held between the upper die 4 and the lower die 5.
  • the bending center of the press die is aligned with the center in the width direction of the preform S 1 .
  • the plate width end portions thus can be pressed evenly on the right and the left at the U-shaped open side of the preform S1.
  • the surfaces of the upper die 4 and the lower die 5 that may be in contact with the preform S 1 have arc portions 4a and 5a, respectively, with a diameter equal or substantially equal to the outer diameter of the steel pipe to be formed and with a central angle ⁇ .
  • This range is pressed into a shape inscribed in the arc with a diameter equal or substantially equal to the outer diameter of the steel pipe.
  • the central angle ⁇ of 360 degrees corresponds to a plate width of 100 [%] to be pressed into the inscribed shape.
  • the central angle ⁇ of the arc portion 4a, 5a is referred to as a constraining range, and the value obtained by dividing this angle by 360 degrees is the range pressed into the shape inscribed in the arc with a diameter equal or substantially equal to the outer diameter of the steel pipe.
  • the arc portion 4a has an arc center at a position coincident with the bending center O p4 of the upper die 4.
  • the arc portion 5a has an arc center at a position coincident with the bending center O p5 of the lower die 5.
  • the upper die 4 has linear portions 4b 1 and 4b 2 connected to respective both ends in the arc direction of the arc portion 4a.
  • the lower die 5 has linear portions 5b 1 and 5b 2 connected to respective both ends in the arc direction of the arc portion 5a.
  • the upper die 4 and the lower die 5 may have small-curvature arc portions having a curvature smaller than that of the arc portions 4a and 5a.
  • the linear portions 4b 1 , 4b 2 , 5b 1 , and 5b 2 or the small-curvature arc portions connected to the arc portions 4a and 5a are symmetric with respect to the bending centers O p4 and O p5 , that is, the centers of the arc portions 4a and 5a. It is preferable that pressing is performed using a die having a radius of an arc portion within a range of ⁇ 3.5 [%] relative to a radius corresponding to the outer radius of the steel pipe. The reason for this will be described later.
  • the preform S 1 held between the upper die 4 and the lower die 5 is pressed down by the upper die 4 and subjected to O-pressing as illustrated in FIG. 4(b) .
  • the portions of the preform S 1 that are opposed to the arc portions 4a and 5a of the upper die 4 and the lower die 5 are constrained by the upper die 4 and the lower die 5, whereas the unbent portions P of the preform S 1 are not constrained by the upper die 4 and the lower die 5.
  • the open pipe S 2 as illustrated in FIG. 4(c) can be formed with a pressing force smaller than the pressing force required when the entire circumference of the preform S 1 is constrained by the upper die 4 and the lower die 5.
  • the preform S 1 is pressed to form the open pipe S 2 into a shape such that a range of 20 [%] or more of the plate width W (equivalent to the central angle ⁇ of 70 degrees or larger) of which center is positioned at the lowermost portion of the U-shaped cross section and a range of 10 [%] or more (equivalent to the central angle ⁇ of 35 degrees or larger) of the plate width W from the plate width end are inscribed in the arc with a diameter equal or substantially equal to the outer diameter of the steel pipe.
  • the range in which the open pipe S 2 is inscribed in the die is substantially the same on the upper die 4 side and the lower die 5 side. That is, when the range of 20 [%] or more of the plate width W of which center is positioned at the lowermost portion of the U-shaped cross section inscribed in the arc with a diameter equal or substantially equal to the outer diameter of the steep pipe is denoted by A, and the total range of 10 [%] or more of the plate width W from both plate width ends inscribed in the arc with a diameter equal or substantially equal to the outer diameter of the steel pipe is denoted by B, it is preferable that Expression (1) is satisfied: 2 A ⁇ B / A + B ⁇ 0.4 where
  • the angles ⁇ 11 and ⁇ 12 between a tangent TL 1 at a W/2 portion that is a plate width center portion and tangents TL 21 and TL 22 at the W/4 portions is 35 degrees or larger and smaller than 90 degrees.
  • the angles ⁇ 21 and ⁇ 22 between tangents TL 31 and TL 32 at the plate width end portions and tangents TL 21 and TL 22 at the W/4 portions is 35 degrees or larger and smaller than 90 degrees.
  • the sum of the angles ⁇ 11 and ⁇ 12 between the tangent TL 1 and the tangents TL 21 and TL 22 is substantially equal to the sum of the angles ⁇ 21 and ⁇ 22 between the tangents TL 31 and TL 32 and the tangents TL 21 and TL 22 .
  • angles need to be defined in consideration of a facility for bending into the U-shaped preform S 1 and the shape of a die for bending the U-shaped preform S 1 into the open pipe S 2 , for the following reasons. If these angles are too large, the distance between the plate width ends is small. If the distance is smaller than the width of the punch support 2b for bending into the U-shaped preform S 1 , it is impossible to obtain the U-shaped preform S 1 . On the other hand, if these angles are too small, the distance between the plate width ends of the U-shaped preform S 1 is large, so that when the U-shaped preform S 1 is placed on the die, the plate width ends are greater than the opening of the upper die 4 and the bending force is unable to be applied. In addition, the distance between the unbent portions P on the right and the left is excessively large to prevent proper placement in the lower die 5.
  • the upper die 4 and the lower die 5 have the following pressing surfaces.
  • the lower die 5 has a pressing surface in such a manner that the pressing surface is not in contact with the preform S 1 , excluding the range of 20 [%] or more (equivalent to the central angle ⁇ of 70 degrees or larger) of the plate width W of which center is positioned at the lowermost portion of the U-shaped cross section, in a state in which the preform S 1 is placed on the lower die 5, and that a part of the lower die 5 is not in contact with the open pipe S 2 in a state in which pressing is completed.
  • the upper die 4 has a pressing surface in such a manner that the pressing surface is not in contact with the preform S 1 in a state in which the preform S 1 is placed on the lower die 5, and that a part of the upper die 4 is not in contact with the open pipe S 2 in a state in which pressing is completed.
  • the center of the press die for use in pressing of the preform S 1 matches the center in the width direction of the preform S 1 . This is because application of a symmetric force to the center in the width direction of the preform S 1 contributes to improvement in shape accuracy of the resultant steel pipe.
  • the preform S 1 is held in a U-shaped posture with the U-shaped open side facing upward. This is because pressing in this posture facilitates the operation. Another reason is that if the U-shaped open side faces downward, the weight of the preform S 1 is exerted on the plate width end portions of the preform S 1 and may cause scratching at the plate width end portions or the die, and this should be avoided.
  • the pressing force is applied to a part W/4 away from the center of the unbent portion P toward the width end portion in the preform S 1 .
  • M F-r-cos ⁇ (F: pressing force, r: radius of circle) at a position where the central angle is away from the pressed portion by an angle ⁇ , and is largest at a position away from the pressed portion by 90 degrees, where the deformation is also largest.
  • the pressing force is then applied to a position away from the center of the unbent portion P by 90 degrees, that is, by 1/4 of the entire circumference, whereby the unbent portion P is effectively deformed.
  • the bending moment is largest at a position away from the position receiving the pressing force by 90 degrees and decreases as the distance from this position increases. Based on this, it is preferable to apply a pressing force to a section away from the center of the unbent portion P toward the plate width end portion by W/4 ⁇ 0.07W in order to produce sufficient plastic deformation in the unbent portion P.
  • the center of the unbent portion P is provided at a section including the position away from the plate width end by W/4.
  • the reason for this is as follows. Although it is preferable to apply a pressing force to a section away from the center of the unbent portion P toward the plate width end portion by W/4 as described above, the contact position between the upper die 4 and the preform S 1 changes, and the position receiving the pressing force also changes, because the shape of the preform S 1 changes in a stage of forming the preform S 1 into the open pipe S 2 .
  • the unbent portion P When the unbent portion P is provided at a section including the position away from the plate width end by W/4 in the preform S 1 , the portion receiving the pressing force is always the plate width end portion of the preform S 1 , so that the unbent portion P is most deformed. By doing so, it is possible to apply deformation to the unbent portion P in a single press, without changing the pressed position. Furthermore, it is preferable to provide the unbent portion P in a range of W/4 ⁇ 0.07W from the position receiving the pressing force, that is, the plate width end of the preform S 1 .
  • the unbent portion P is provided at a section including a section away from the plate width end of the preform S 1 by W/4.
  • FIG. 6 is a graph illustrating the relation between the open amount of the seam gap portion G of the open pipe S 2 and the constraining range, in conjunction with a press load.
  • the relation between the open amount and the constraining range illustrated in FIG. 6 and the press load are those obtained when a steel pipe with a tensile strength of 630 [MPa], an outer diameter of 660.4 [mm], and a pipe thickness of 40.0 [mm] is formed by welding both edges of the open pipe S 2 and thereafter performing shape correction by pipe expanding at a pipe expanding ratio of 1 [%].
  • the preform S 1 after press bending is provided with an unbent portion P having a length of W/12 at a portion W/4 from each of the plate width ends on both sides.
  • the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the W/4 portion that is a section away from the plate width end by W/4 is 75 degrees, and the angle ⁇ 21 , ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion is 75 degrees.
  • This preform S 1 is held between the upper die 4 and the lower die 5 having the same constraining range.
  • the pressing amount is set such that the distance between the portions at W/2 of the open pipe S 2 is equal to the diameter before pipe expanding (the amount of pressing-down in O-pressing is set such that the longitudinal diameter agrees with the diameter before pipe expanding).
  • FIGS. 7(a) to 7(c) are diagrams schematically illustrating a deformation state when the open pipe S 2 is formed using the upper die 4 and the lower die 5 with a constraining range of 0 degrees.
  • the arc portions 4a and 5a are arcs having a diameter 1.16 times as large as the steel pipe outer diameter such that the upper die 4 is in contact only with both edges of the preform S 1 and the lower die 5 is in contact only with the plate width center portion of the preform S 1 .
  • FIG. 7(a) to 7(c) are diagrams schematically illustrating a deformation state when the open pipe S 2 is formed using the upper die 4 and the lower die 5 with a constraining range of 0 degrees.
  • the diameter of the arc portion 5a of the lower die 5 is larger than the steel pipe diameter such that when the cross section of the preform S 1 is compared to a clock, the 6 o'clock portion alone is in contact with the lower die 5. Because of this, as illustrated in FIG. 7(b) , the 6 o'clock portion of the preform S 1 and the vicinity thereof are bent back to conform to the arc portion 5a of the lower die 5 during O-pressing, and the radius of curvature becomes larger than the steel pipe diameter. As a result, after O-pressing, as illustrated in FIG. 7(c) , the open amount of the seam gap portion G of the open pipe S 2 is large, in combination with the springback at the 3 o'clock portion and the 9 o'clock portion of the preform S 1 .
  • FIG. 8 is a graph illustrating the relation between the constraining range and the roundness of a steel pipe before pipe expanding when the seam gap portion G of the open pipe S 2 is closed by welding.
  • the constraining range is 60 degrees
  • the roundness is worse than when the constraining range is 0 degrees.
  • the roundness improves.
  • the constraining range is 70 degrees or larger
  • the roundness is better than when the constraining range is 0 degrees. It also can be understood that the roundness is most improved when the constraining range is 100 degrees to 110 degrees.
  • FIG. 9 is a graph illustrating the relation between the constraining range and the press load.
  • the constraining range increases as the constraining range increases. Increasing the constraining range reduces the open amount of the seam gap portion G of the open pipe S 2 , but the increased press load requires a larger size of press facility. It is therefore preferable to reduce the constraining range in a range in which a desired open amount is obtained.
  • the constraining range is set to 150 degrees or smaller in order to set the press load to 90 [%] or smaller of the press load required when the individual constraining ranges of the upper die 4 and the lower die 5 for constraining the entire circumference of the preform S 1 with the upper die 4 and the lower die 5 are 180 degrees.
  • FIG. 10 is a graph illustrating the result of the open amount of the seam gap portion G of the open pipe S 2 when the individual constraining ranges of the upper die 4 and the lower die 5 are changed.
  • FIG. 11 is a graph illustrating the result of the roundness of the steel pipe before pipe expanding that is formed by closing the seam gap portion G of the open pipe S 2 by welding when the individual constraining ranges of the upper die 4 and the lower die 5 are changed.
  • FIG. 12 is a graph illustrating the result of the press load when the individual constraining ranges of the upper die 4 and the lower die 5 are changed.
  • the target steel pipe has a tensile strength of 630 [MPa], an outer diameter of 660.4 [mm], and a pipe thickness of 40.0 [mm], which are the same as those in FIG. 6 , FIG. 8, and FIG. 9 .
  • the horizontal axis represents the average value of constraining ranges of the upper die 4 and the lower die 5, and different constraining ranges in the lower die 5 are represented by different symbols. In the figure, for example, "lower 60 degrees” means that the constraining range in the lower die 5 is 60 degrees.
  • the open amount of the seam gap portion G of the open pipe S 2 decreases.
  • the constraining range of one of the upper die 4 and the lower die 5 is smaller than 60 degrees, the roundness of the steel pipe is worse. Accordingly, although the individual constraining ranges of the upper die 4 and the lower die 5 may not necessarily be equal between the upper die 4 and the lower die 5, it is desirable that the constraining ranges of the upper die 4 and the lower die 5 both exceed 60 degrees in order to obtain a shape with satisfactory roundness of a steel pipe.
  • the difference between upper and lower constraining ranges is set to less than 40 [%] of the average value of upper and lower constraining ranges, further preferably 30 [%] or less. It is preferable that the difference between upper and lower constraining ranges is less than 30 degrees.
  • the relation of the difference between upper and lower constraining ranges and the average value of upper and lower constraining ranges can be said as follows.
  • FIG. 13 is a graph illustrating the result of the open amount of the seam gap portion G when the constraining range of the upper die 4 and the constraining range of the lower die 5 are the same and the length L of the unbent portion P of the preform S 1 after press bending is changed.
  • FIG. 14 is a graph illustrating the result of the roundness of the steel pipe before pipe expanding when the constraining range of the upper die 4 and the constraining range of the lower die 5 are the same and the length L of the unbent portion P of the preform S 1 after press bending is changed.
  • FIG. 15 is a graph illustrating the result of the press load when the constraining range of the upper die 4 and the constraining range of the lower die 5 are the same and the length L of the unbent portion P of the preform S 1 after press bending is changed.
  • the angle between the tangent at the plate width center portion and the tangent at the W/4 portion that is a section away from the plate width end by W/4 is ⁇ 11 , ⁇ 12
  • the angle between the tangent at the plate width end portion and the tangent at the W/4 portion is ⁇ 21, ⁇ 22
  • all of these angles are set to an equal value and changed in accordance with the width of the unbent portion P.
  • the horizontal axis represents the average value of the constraining range of the upper die 4 and the constraining range of the lower die 5.
  • the open amount of the seam gap portion G of the open pipe S 2 can be reduced by increasing the length L of the unbent portion P of the preform S 1 and reducing the angles ⁇ 11 , 6 12 , ⁇ 21, and ⁇ 22 of the tangents, without causing a difference in roundness or press load of the steel pipe due to the length L.
  • FIG. 16 is a graph illustrating the result of the open amount of the seam gap portion G of the open pipe S 2 when the arc portion radiuses of the upper die 4 and the lower die 5 are changed.
  • FIG. 17 is a graph illustrating the result of the press load when the arc portion radiuses of the upper die 4 and the lower die 5 are changed.
  • the central angles of the arc portions 4a and 5a of the upper die 4 and the lower die 5 are 45 degrees, and while the arc portion radiuses, which are the radiuses of the arc portions 4a and 5a, are changed, a steel pipe having a tensile strength of 630 MPa, an outer diameter of 660.4 [mm], and a pipe thickness of 40.0 [mm] is pressed down by O-pressing such that the longitudinal diameter agrees with the diameter before pipe expanding.
  • the horizontal axis represents the ratio between the arc portion radius and the steel pipe outer radius (radius corresponding to the steel pipe outer diameter). When the arc portion radius is larger than the steel pipe outer radius, the ratio is greater than 1.0, and when the arc portion radius is smaller than the steel pipe outer radius, the ratio is smaller than 1.0.
  • the open amount of the seam gap portion G is smallest.
  • the arc portion radius of the upper die 4 and the lower die 5 is larger than the steel pipe outer radius, bending-back deformation occurs at the 6 o'clock portion of the preform S 1 and the vicinity thereof as illustrated in FIG. 7 , so that the open amount of the seam gap portion G increases as the arc portion radius of the upper die 4 and the lower die 5 increases.
  • the open amount of the seam gap portion G increases as the arc portion radius decreases.
  • the open amount of the seam gap portion G is kept to 40 [mm] or smaller when the arc portion radius of the upper die 4 and the lower die 5 is a radius equivalent to the steel pipe outer radius ⁇ 3.5 [%].
  • the press load increases as the arc portion radius decreases.
  • the arc portion radius is small, it is necessary to determine the radius considering the load of the press machine.
  • a steel plate provided with a groove using an edge mirror and formed to have a plate width W of 1928 [mm] with a length of 1000 [mm], a plate thickness of 40 [mm], and a tensile strength of 635 [MPa] was subjected to edge bending, followed by press bending, to prepare a preform S 1 .
  • O-pressing was performed on this preform S 1 with a press machine of 30 [MN] using the upper die 4 and the lower die 5 with various constraining ranges to form preforms A and B.
  • Table 1 and Table 2 show the shapes of the preforms A and B.
  • the initial alphabets A and B in the "No.” column indicate the shapes of preforms (preforms A and B), and the numerals following the alphabets A, B, and C indicate a combination of the constraining ranges of the upper die 4 and the lower die 5.
  • Table 1 shows a preform A under Condition A in which an unbent portion was provided with a width of 160 [mm] (W/12) of which center is positioned at the W/4 portion from the plate width end, the angle ⁇ 21, ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 65 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 73 degrees.
  • Table 2 shows a preform B under Condition B in which an unbent portion was provided with a width of 321 [mm] (W/6) (the width twice that in Condition A) of which center is positioned at the W/4 portion from the plate width end, the angle ⁇ 21, ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 59 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 61 degrees.
  • the preforms A and B are each symmetric with respect to a straight line connecting the center of the plate width end portion and the plate width 1/2, and Table 1 and Table 2 show the value of the portion at the plate width 1/2.
  • the amount of pressing-down in O-pressing was set such that the distance between the outer surface side of the W/2 portion and the outer surface side of the plate width end portion was 654 [mm].
  • the seam gap portion G of the open pipe S 2 was welded to form a steel pipe having an outer diameter of 654 [mm]. Thereafter, the diameter of the steel pipe was measured at eight points at a pitch of 22.5 degrees in the circumferential direction, and the difference between the maximum diameter and the minimum diameter was obtained.
  • Table 1 and Table 2 also show die shape (constraining range), press load, open amount, and roundness. Here, the roundness is a numeral obtained by dividing the difference between the maximum and the minimum by the steel pipe outer diameter (the average value of all the measured values of the diameter).
  • a steel plate provided with a groove using an edge mirror and formed to have a width of 1639 [mm] with a length of 1000 [mm], a plate thickness of 31.8 [mm], and a tensile strength of 779 [MPa] was subjected to edge bending, followed by press bending, to prepare a preform S 1 . Subsequently, O-pressing was performed on this preform S 1 , using the upper die 4 and the lower die 5 with various constraining ranges with a press machine of 30 [MN] to form preforms A and B.
  • Table 3 and Table 4 show the shapes of the preforms A and B.
  • the initial alphabets A and B in the "No.” column indicate the shapes of preforms (preforms A and B) and the numerals following the alphabets A and B each indicate a combination of the constraining ranges of the upper die 4 and the lower die 5.
  • Table 3 shows a preform A under Condition A in which an unbent portion was provided with a width of 137 [mm] (W/12) of which center is positioned at the W/4 portion from the plate width end, the angle ⁇ 21 , ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 65 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 72 degrees.
  • Table 4 shows a preform B under Condition B in which an unbent portion was provided with a width of 273 [mm] (W/6) (the width twice that in Condition A) of which center is positioned at W/4 from the plate width end, the angle ⁇ 21, ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 59 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center and the tangent at the W/4 portion was 61 degrees.
  • the preforms A and B are each symmetric with respect to a straight line connecting the center of the plate width end portion and the plate width 1/2.
  • Table 3 and Table 4 show the values of the portion at the plate width 1/2.
  • the amount of pressing-down in O-pressing was set such that the distance between the outer surface side of the W/2 portion and the outer surface side of the plate width end portion was 553 [mm].
  • the seam gap portion G of the open pipe S 2 was welded to form a steel pipe having an outer diameter of 553 [mm]. Thereafter, the diameter of the steel pipe was measured at eight points at a pitch of 22.5 degrees in the circumferential direction, and the difference between the maximum diameter and the minimum diameter was obtained.
  • Table 3 and Table 4 also show die shape (constraining range), press load, open amount, and roundness. Here, the roundness is a numeral obtained by dividing the difference between the maximum and the minimum by the steel pipe outer diameter.
  • a steel plate provided with a groove using an edge mirror and formed to have a plate width of 2687 [mm] with a length of 1000 [mm], a plate thickness of 50.8 [mm], and a tensile strength of 779 [MPa] was subjected to edge bending, followed by press bending, to prepare a preform S 1 .
  • O-pressing was performed on this preform S 1 using the upper die 4 and the lower die 5 with various constraining ranges with a press machine of 30 [MN] to form preforms A and B.
  • Table 5 and Table 6 show the shapes of the preforms A and B.
  • the initial alphabets A and B in the "No.” column indicate the shapes of preforms (preforms A and B), and the numerals following the alphabets A and B indicate a combination of the constraining ranges of the upper die 4 and the lower die 5.
  • Table 5 shows a preform A under Condition A in which an unbent portion was provided with a width of 224 [mm] (W/12) of which center is positioned at the W/4 portion from the plate width end, the angle ⁇ 21, ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 73 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 72 degrees.
  • Table 6 shows a preform B under Condition B in which an unbent portion was provided with a width of 448 [mm] (W/6) (the width twice that in Condition A) of which center is positioned at W/4 from the plate width end, the angle ⁇ 21, ⁇ 22 between the tangent at the plate width end portion and the W/4 portion was 58 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 59 degrees.
  • the preforms A and B are each symmetric with respect to a straight line connecting the center of the plate width end portion and the plate width 1/2, and Table 5 and Table 6 show the value of the portion at the plate width 1/2.
  • the amount of pressing-down in O-pressing was set such that the distance between the outer surface side of the W/2 portion and the outer surface side of the plate width end portion was 905 [mm].
  • the seam gap portion G of the open pipe S 2 was welded to form a steel pipe having an outer diameter of 905 [mm]. Thereafter, the diameter of the steel pipe was measured at eight points at a pitch of 22.5 degrees in the circumferential direction, and the difference between the maximum diameter and the minimum diameter was obtained.
  • Table 5 and Table 6 also show die shape (constraining range), press load, open amount, and roundness. Here, the roundness is a numeral obtained by dividing the difference between the maximum and the minimum by the steel pipe outer diameter.
  • the open amount is small, and the roundness is also satisfactory.
  • the products with a constraining range of 90 degrees to 110 degrees have a roundness of 1.0 [%] or lower even without pipe expanding. The smaller the average value of the constraining range is, the smaller the press load is.
  • a steel plate provided with a groove using an edge mirror and formed to have a plate width of 1826 to 2032 [mm] with a length of 1000 [mm], a plate thickness of 40 [mm], and a tensile strength of 635 [MPa] was subjected to edge bending, followed by press bending, to prepare a preform S 1 .
  • O-pressing was performed on this preform S 1 using a variety of the upper dies 4 and the lower dies 5 with an arc portion radius of 327 mm and a constraining range of 45 degrees, with a press machine of 30 [MN] to form preforms D1 to D11.
  • Table 7 shows the bending conditions of the preforms D1 to D11.
  • an unbent portion was provided with a width of W/12 of which center is positioned at the W/4 portion from the plate width end, in accordance with the initial plate width W, the angle ⁇ 21 , ⁇ 22 between the tangent at the plate width end portion and the tangent at the W/4 portion was 75 degrees, and the angle ⁇ 11 , ⁇ 12 between the tangent at the plate width center portion and the tangent at the W/4 portion was 75 degrees.
  • the pressing-down was performed such that the distance between the outer surface side of the W/2 portion and the outer surface side of the plate width end attained a value corresponding to the initial plate width W as shown in Table 7.
  • Table 7 also shows the outer diameter of the steel pipe after pressing down with O-press.
  • Table 7 also shows the press load and the open amount as the results.
  • the guideline of the arc portion radiuses of the upper die 4 and the lower die 5 is 0.96 to 1.04 of the steel pipe outer radius.
  • a method of manufacturing a steel pipe for efficiently forming a steel pipe with high roundness and a press die can be provided.
EP18933413.9A 2018-09-14 2018-09-14 Procédé de fabrication de tuyau en acier et matrice de presse Pending EP3851220A4 (fr)

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Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE414129B (sv) 1977-01-11 1980-07-14 Carbox Ab Sett vid formning av ror fran ett i huvudsak plant emne
DE3632952A1 (de) * 1986-09-27 1988-04-07 Hoesch Ag Verfahren und vorrichtung zur kontinuierlichen herstellung rohrfoermiger koerper mittels laser-laengsnahtschweissung
JPH11285729A (ja) * 1998-04-01 1999-10-19 Sumitomo Metal Ind Ltd Ｕｏｅ鋼管の製造方法
JP2001009524A (ja) 1999-06-30 2001-01-16 Toyota Motor Corp 筒状体の製造方法
JP2002178026A (ja) 2000-12-15 2002-06-25 Kawasaki Steel Corp Ｕｏｅパイプの製造方法
KR100530325B1 (ko) * 2001-04-30 2005-11-22 주식회사 포스코 가변식 스트립 선단부 절곡장치
JP4759868B2 (ja) 2001-07-30 2011-08-31 Ｊｆｅスチール株式会社 Ｕｏｅ管のｏプレス用金型およびｕｏｅ管の製造方法
DE10232098B4 (de) 2002-07-15 2004-05-06 Sms Meer Gmbh Vorrichtung zum Herstellen von Rohren aus Blechtafeln
JP4388767B2 (ja) 2003-06-30 2009-12-24 川崎油工株式会社 パイププレス成形方法
JP2005324255A (ja) 2005-06-17 2005-11-24 Nakajima Steel Pipe Co Ltd 丸鋼管の製造方法
JP5135540B2 (ja) 2007-06-28 2013-02-06 新日鐵住金株式会社 鋼管製造設備及び鋼管製造方法
KR20100106700A (ko) * 2009-03-24 2010-10-04 진영희 자동차의 고무부싱용 관체 및 그 제조방법
JP5393358B2 (ja) 2009-09-08 2014-01-22 住友重機械工業株式会社 板曲げプレス
JP5696357B2 (ja) 2009-11-27 2015-04-08 セイコーエプソン株式会社 搬送ローラーの製造方法、搬送ローラー、印刷装置
EP2529849B1 (fr) * 2011-05-31 2021-03-10 SMS group GmbH Dispositif et procédé de fabrication de tuyaux fendus à partir de plaques de tôle
EP2818260B1 (fr) * 2012-04-02 2016-08-03 JFE Steel Corporation Tube en acier uoe et structure
CN105228766B (zh) 2013-05-20 2017-11-28 杰富意钢铁株式会社 弯曲冲压装置及弯曲冲压方法以及钢管的制造装置及钢管的制造方法
EP3006133B1 (fr) * 2013-05-24 2017-08-16 JFE Steel Corporation Procédé de fabrication d'un tube d'acier
EP3006128B1 (fr) * 2013-05-29 2018-10-24 JFE Steel Corporation Procédé de fabrication de tuyau en acier soudé
EP3006129B1 (fr) 2013-05-30 2019-07-10 JFE Steel Corporation Procédé de moulage par pressage d'un tuyau d'acier et procédé de fabrication de ce dernier
JP6262166B2 (ja) * 2014-03-31 2018-01-17 Ｊｆｅスチール株式会社 ベンディングプレス成形用金型
CA2967914C (fr) * 2014-11-25 2020-03-24 Jfe Steel Corporation Procede de fabrication de tuyau en acier et moule de presse utilise dans ledit procede
EP3597322A4 (fr) * 2017-03-15 2021-01-13 JFE Steel Corporation Moule de presse et procédé de fabrication de tuyau en acier

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CN112638558B (zh) 2022-12-16
JP6791397B2 (ja) 2020-11-25
WO2020054051A1 (fr) 2020-03-19
EP3851220A4 (fr) 2021-09-22
KR102425607B1 (ko) 2022-07-27
KR20210041032A (ko) 2021-04-14

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