WO2020054051A1 - 鋼管の製造方法及びプレス金型 - Google Patents

鋼管の製造方法及びプレス金型 Download PDF

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Publication number
WO2020054051A1
WO2020054051A1 PCT/JP2018/034145 JP2018034145W WO2020054051A1 WO 2020054051 A1 WO2020054051 A1 WO 2020054051A1 JP 2018034145 W JP2018034145 W JP 2018034145W WO 2020054051 A1 WO2020054051 A1 WO 2020054051A1
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WO
WIPO (PCT)
Prior art keywords
steel pipe
molded body
mold
press
range
Prior art date
Application number
PCT/JP2018/034145
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
正之 堀江
洸介 日当
友裕 川野
征哉 田村
Original Assignee
Ｊｆｅスチール株式会社
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スチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to RU2021110038A priority Critical patent/RU2769596C1/ru
Priority to PCT/JP2018/034145 priority patent/WO2020054051A1/ja
Priority to KR1020217006550A priority patent/KR102425607B1/ko
Priority to JP2019547161A priority patent/JP6791397B2/ja
Priority to BR112021004322-5A priority patent/BR112021004322A2/pt
Priority to CN201880097036.2A priority patent/CN112638558B/zh
Priority to EP18933413.9A priority patent/EP3851220A4/en
Publication of WO2020054051A1 publication Critical patent/WO2020054051A1/ja

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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 for manufacturing a steel pipe and a press die used in the method for manufacturing the steel pipe.
  • UOE forming technique is an open pipe, which is a pipe having a seam gap between sheet width ends facing each other in the circumferential direction, by first pressing a steel sheet into a U-shape and then pressing it into an O-shape.
  • the seam gap of this open pipe is butt-joined by welding to form a steel pipe, and then the steel pipe is expanded to further increase its diameter.
  • a high press force is required in a process of forming an open pipe by pressing a steel sheet into a U-shape or an O-shape, so a large-scale press machine must be used. There is no situation.
  • the force required to close the seam gap portion by abutting the facing plate width ends increases, and the equipment for closing the seam gap portion increases in size.
  • the force to open the seam gap portion due to springback acts on the welded portion after welding the seam gap portion where the opening amount is too large, welding defects are likely to occur, and if the force is too large, welding will be performed. The part breaks.
  • Patent Documents 1 to 4 disclose techniques for reducing the opening amount of the seam gap portion of the open pipe after press bending.
  • Patent Literature 1 discloses a technique for reducing the width of a punch support and reducing the opening amount of a seam gap portion of an open pipe by freely rotating a connecting portion between a punch tip and a punch support. ing.
  • Patent Literature 2 an interval maintaining means for restricting the movement of the plate material in a direction orthogonal to the movement direction of the punch is provided, and a large pressure is applied in the final bending process without the plate width end contacting the punch support.
  • Patent Literature 3 discloses a technique for measuring a gap between a plate width end portion and a punch support after a final rolling-down process, and reducing the gap as much as possible to reduce the opening amount of a seam gap portion of an open pipe. I have. Further, in Patent Literature 4, the amount of reduction by the punch in the final step is determined based on the time when the interval between the sheet width ends becomes a predetermined value at the time of the reduction in the final bending step. A technique for reducing the opening amount of the seam gap portion of the open pipe regardless of the difference in shape caused by the above has been disclosed.
  • Patent Documents 5 to 9 disclose techniques for further processing the open pipe after press bending to reduce the opening amount of the seam gap.
  • Patent Literature 5 discloses a technique in which hot roll forming is performed on a steel pipe after press bending to form the pipe with a small load.
  • Patent Literature 6 discloses that a strain detector that can detect inclination or distortion of a pressing member mounted on a slide is provided, and that the pressing member can be tilted in accordance with the detection of the inclination or distortion of the distortion detector.
  • Patent Document 7 discloses that at least one bending step acting on the left and right inner surfaces of a plate material with respect to a center defined by a longitudinal axis of an upper tool entering a plate material to be gradually formed, compared with other bending steps. Forming a slit tube with a non-circular preform by means of a slight shaping and then acting on the non-circular preform from the outside in each case in the pre-slightly shaped area on both sides of the center.
  • Patent Document 8 discloses that a molded body having a flat portion between at least two pipe curved portions is subjected to plastic deformation only at least at one flat portion to obtain a predetermined curvature.
  • Patent Document 9 discloses that an open pipe is formed by rolling down a formed body having a lightly worked portion having a very small curvature compared to other regions or an unprocessed portion having no bending process.
  • a method is disclosed in which a pressing force is applied without restraining a lightly processed portion or an unprocessed portion to form a pipe with a slit portion closed. Also, it is recommended that when pressed, the molded body be held in a mold in a U-shape with the open portion facing upward and supported at the lowermost end of the molded body.
  • Patent Documents 10 and 11 disclose techniques for manufacturing a UOE pipe having a product diameter different from the inner diameter of the O-press die and the outer diameter of the product pipe.
  • the mold disclosed in Patent Literature 10 has a shape in which the inner surfaces of upper and lower dies have only a part of a horizontally long oval cut out, and the operation of the die is described with reference to FIG. 4A, the O tube is in contact with the entire inner surface of the O press die.
  • an arc having a radius larger than the outer diameter of the product is formed on the inner surface, the end surface is ground in advance, and a mold having a sufficiently large gap is used.
  • a method is disclosed in which, after compression, the formed pipe is rotated by approximately 90 [°] and O-pressed again to form a circular shape. In the first O-press step at this time, the steel pipe is in close contact with the entire surface of the mold.
  • Patent Literature 5 has a problem that the production cost is significantly increased when the consumption of heat energy for heating is included. Further, in the case of using a plate material manufactured through a thermomechanical treatment process to have both strength, toughness, and weldability, this technique may impair its characteristics. In the techniques disclosed in Patent Documents 6 to 8, since a molding material or a non-circular preform is separately molded on each of the right and left sides, a seam gap portion or a slit portion serving as a welded portion when the deformation amount is different on the left and right. In addition, there is a concern that a step (mismatch) may be formed.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a steel pipe and a press die capable of efficiently forming a steel pipe having high roundness.
  • a method of manufacturing a steel pipe according to the present invention includes bending a sheet material having both ends in the width direction to be bent three or more times along the width direction. Forming a molded body having a U-shaped cross section by performing processing, and then pressing the molded body to form an open pipe having a seam gap portion in the longitudinal direction thereof, and then forming the seam.
  • a lightly processed portion having a smaller curvature than other regions, or an unprocessed portion with no bending process, and the shape of the open pipe is the lowest of the U-shaped cross section.
  • the plate width W of the U-shaped cross section inscribed in an arc having the same diameter or substantially the same diameter as the outer diameter of the steel pipe is centered.
  • the range of 20% or more is defined as A, and the sum of the ranges of 10% or more of the width W from both ends of the width inscribed in an arc having the same or substantially the same diameter as the outer diameter of the steel pipe is defined as B.
  • B is characterized by satisfying Expression (1). 2
  • one of the pair of molds may be formed into the other mold so that the U-shaped open side of the molded body faces the other mold.
  • the molded body is sandwiched between the pair of molds and the molded body is subjected to press working, the other mold is in a state where the molded body is placed on the other mold.
  • the formed body does not contact except for a range in which the outer diameter of the steel pipe is inscribed in an arc having the same diameter or substantially the same diameter, and the press working is completed.
  • a part of the other mold has a processing surface that does not come into contact with the open tube, and the one mold has the molded body mounted on the other mold, In the state where the molded body does not contact and press processing is completed, a part of the one mold contacts the open pipe. It is characterized in that it comprises a free working surface.
  • a mold having a radius of an arc portion in a range of ⁇ 3.5 [%] with respect to a radius corresponding to an outer radius of the steel pipe is used. Press working.
  • a center of a press die used for press working of the molded body and a center in a width direction of the molded body are aligned.
  • the feature is that they match.
  • the method for manufacturing a steel pipe according to the present invention is characterized in that, in the above invention, the molded body is held in a U-shaped posture with the U-shaped open side facing upward.
  • a press die according to the present invention is a press die used in the method of manufacturing a steel pipe of the above invention, wherein the press die comprises a pair of pressing members for sandwiching the molded body,
  • the surface of the mold that can come into contact with the molded body has a radius corresponding to the outer radius of the steel pipe ⁇ 3.5 [%] so that the center of the arc is located at the position corresponding to the processing center of each mold.
  • the center angle of the arc portion in each mold is 70 degrees or more, and the sum of the angles of the center angles of both molds is less than 360 degrees. It is characterized by the following.
  • the press die according to the present invention is characterized in that, in the above invention, the angles of the central angles of the two dies are the same.
  • each die is connected to both ends of the arc portion in the arc direction, a straight portion, or a small curvature arc portion having a smaller curvature than the arc portion. It is characterized by having.
  • a method of manufacturing a steel pipe according to the present invention is characterized by using the press die of the above invention in the method of manufacturing a steel pipe of the above invention.
  • the method for manufacturing a steel pipe and the press die according to the present invention have an effect that a steel pipe having high roundness can be efficiently formed.
  • FIG. 1 is an external perspective view of a die, a punch, and the like used for molding a molded body having a U-shaped cross section by a press bend method according to the embodiment.
  • FIG. 2 is a diagram showing a procedure for forming a molded body having a U-shaped cross section by a press bend method.
  • FIG. 3 is a cross-sectional view of a formed body having a U-shaped cross section.
  • FIG. 4 is a diagram schematically illustrating a process of forming an open pipe by applying an O-press to the formed body.
  • FIG. 5 is an explanatory diagram of the arc portion, the straight portion, and the central angle of the upper mold and the lower mold.
  • FIG. 6 is a graph showing the relationship between the opening amount of the seam gap portion of the open pipe and the constraint range together with the press load.
  • FIG. 7 is a diagram schematically illustrating a deformation state when an open tube is formed using an upper mold and a lower mold having a constraint range of 0 degrees.
  • FIG. 8 is a graph showing the relationship between the constraint range and the roundness of the steel pipe before expansion when the seam gap of the open pipe is closed by welding.
  • FIG. 9 is a graph showing the relationship between the restraint range and the press load.
  • FIG. 10 is a graph showing the result of the opening amount of the seam gap portion of the open pipe when the individual constraint ranges of the upper mold and the lower mold are changed.
  • FIG. 11 is a graph showing the results of roundness of a steel pipe before expansion, which is formed by closing the seam gap portion of the open pipe by welding when the individual constraint ranges of the upper die and the lower die are changed. It is.
  • FIG. 12 is a graph showing the results of the press load when the individual constraint ranges of the upper mold and the lower mold are changed.
  • FIG. 13 shows the opening of the seam gap when the length of the lightly processed portion or the unprocessed portion of the molded body after press bend is changed while the constraint range of the upper mold and the constraint range of the lower mold are the same. 4 is a graph showing the results of the amounts.
  • FIG. 12 is a graph showing the results of the press load when the individual constraint ranges of the upper mold and the lower mold are changed.
  • FIG. 13 shows the opening of the seam gap when the length of the lightly processed portion or the unprocessed portion of the molded body after press bend is changed while the constraint range of the upper mold and the constraint range of the lower mold are the same
  • FIG. 14 shows a case where the constraint range of the upper mold and the constraint range of the lower mold are the same, and the length of the lightly processed portion or the unprocessed portion of the molded body after press bend is changed. It is a graph which shows the result of roundness.
  • FIG. 15 shows the results of the press load when the length of the lightly worked portion or the unprocessed portion of the molded body after press bend is changed while the constraint range of the upper mold and the constraint range of the lower mold are the same. It is a graph.
  • FIG. 16 is a graph showing the result of the opening amount of the seam gap portion of the open tube when the radius of the arc portion of the upper mold and the lower mold is changed.
  • FIG. 17 is a graph showing the results of the press load when the radii of the arc portions of the upper mold and the lower mold are changed.
  • FIG. 1 is an external perspective view of a die 1 and a punch 2 used for forming a molded body having a U-shaped cross section by a press bend method according to the present embodiment.
  • the die 1 is disposed in the transport path of the plate S formed by the plurality of transport rollers 3 and includes a pair of left and right bar members 1a and 1b that support the plate S at two locations along the plate transport direction. Have been. Further, the distance e between the rod-shaped members 1a and 1b in the plate material transport direction can be changed according to the size of the steel pipe to be finally formed.
  • the punch 2 is movable in a direction to approach and separate from the die 1.
  • the punch 2 has the same shape as the downwardly projecting punch tip 2 a that presses the plate material S and the back surface (upper end face) of the punch tip 2 a.
  • a punch support 2b that supports the punch tip 2a.
  • the punch support 2b has an upper end connected to a driving unit (not shown), and can apply a pressing force to the punch tip 2a by the driving unit.
  • Figure 2 shows a procedure for molding the molded body S 1 forming a U-shaped cross section by pressing bend method. This procedure is performed on the plate material S that has been subjected to the edge bending in advance from the top to the bottom of the left column of FIG. 2, then from the top to the bottom of the center column of FIG. 2, and finally to the right column of FIG. This specifically shows an example of the case where the bending and the feeding of the plate material S are performed. Arrows attached to the punch 2 and the plate S in FIG. 2 indicate the moving directions of the punch 2 and the plate S at each stage.
  • the plate S is subjected to an end bending process.
  • the edge bending is performed on the edge of the sheet width, which is relatively hard to bend, as compared with the case where the sheet S is bent using the die 1 and the punch 2.
  • the roundness of the steel pipe is an index indicating how close the cross-sectional shape of the steel pipe is to a circle, and the difference between the maximum and the minimum of the variation from the approximate arc over the entire circumference of the steel pipe is expressed by the steel pipe diameter.
  • the pipe is circumferentially divided into eight equal parts, twelve equal parts, sixteen equal parts, or twenty-four equal parts, and outer diameters are measured at opposing positions.
  • the maximum diameter and the minimum diameter are Dmax and Dmin , respectively, the roundness [%] is defined by ⁇ ( Dmax- Dmin ) / D ⁇ ⁇ 100. The closer the roundness is to zero, the closer the cross-sectional shape of the steel pipe is to a perfect circle.
  • the plate material S provided with the end bending portion is placed on the die 1 shown in FIG. 1, and while the plate material S is intermittently fed at a predetermined feed amount, the plate material S is subjected to the procedure shown in FIG. along the width direction it is 3 times or more the bending undergone a is formed into the molded body S 1 forming a U-shaped cross section as a whole.
  • Figure 3 is a cross-sectional view of a shaped body S 1 forming a U-shaped cross section.
  • a portion of the molded body S 1, W / 4 parts is a part especially apart each W / 4 from the strip width end And an unprocessed portion P in which bending is omitted.
  • the unprocessed portion P can be provided by increasing the feed of the plate material S and omitting the pressing by the punch 2.
  • a portion of the molded body S 1, in particular about respective from strip width end W / 4 parts of the unprocessed portion P without curvature than the other portion in comparison with a small (other portions, very small A lightly processed portion (with a curvature) may be provided.
  • lightly processed portion P may be appropriately read as “lightly processed portion”.
  • the lightly processed portion can be provided by reducing the amount of pressing applied by the punch 2 to a value smaller than that of the other portions.
  • the shape of the punch 2 shown in FIGS. 1 and 2 is an I-shape in which the width of the punch tip 2a in the sheet conveying direction is the same as the width of the punch support 2b in the sheet conveying direction.
  • the shape of the punch 2 is not limited to this.
  • a substantially inverted T-shaped punch in which the width of the punch tip 2 a in the plate material transport direction is larger than the width of the punch support 2 b in the plate material transport direction can be used.
  • the width of the punch support 2b in the plate material transport direction is the same, the use of the substantially inverted T-shaped punch 2 makes it possible to press the plate S with one pressing as compared with the case of using the I-shaped punch 2. Thus, a larger area can be pressed, and the number of times of pressing can be reduced.
  • the upper mold 4 and the lower mold 5 are a pair of molds as shown in FIG. 4 comprising a molded body S 1 using a press mold to O-shape by performing O press pressing, between the plate width end portions which face each other in the circumferential direction is a tubular body having a seam gap G open pipe to form the S 2.
  • FIGS. 4 (a) (as U-shaped open side of the molded body S 1 is directed upward) upper mold 4 and the molded body S 1 of the U-shape so that the open side faces, bottom install a molded body S 1 in a mold 5, sandwiching the molded body S 1 between the upper mold 4 and the lower mold 5. Further, when pressing of the molded body S 1 is designed so as to coincide with the processing center of the press die, and a center in the width direction of the molded body S 1. Thereby, on the U-shaped open side of the molded body S1, it is possible to uniformly press the left and right ends of the plate width.
  • the surface that may contact the shaped body S 1 of the upper mold 4 and the lower mold 5, the center angle ⁇ a outer diameter and the same diameter or substantially the same diameter of the steel pipe to be molded Are formed, and this area is pressed into a shape inscribed in an arc having the same or substantially the same diameter as the outer diameter of the steel pipe.
  • the case where the central angle ⁇ is 360 degrees corresponds to the case where 100% of the plate width is pressed into the inscribed shape.
  • the central angle ⁇ of the arc portions 4a and 5a is referred to as a constraint range, and a value obtained by dividing the angle by 360 degrees is a shape inscribed in an arc having the same diameter or substantially the same diameter as the outer diameter of the steel pipe. This is the range to be pressed.
  • Arc portion 4a is arc center to a position which coincides with the processing center O p4 of the upper mold 4 is positioned, the arc portion 5a, arc center is located at a position which coincides with the processing center O p5 of the lower die 5 are doing.
  • the upper mold 4 has straight portions 4b 1 and 4b 2 connected to both ends of the arc portion 4a in the arc direction, and the lower mold 5 has straight lines connected to both ends of the arc portion 5a in the arc direction. and a section 5b 1, 5b 2.
  • the arc portion 4a instead of the straight portion 4b 1, 4b 2, 5b 1 , 5b 2, the arc portion 4a, so as to have a small curvature arc portion curvature is smaller than the 5a Is also good.
  • arc portions 4a, the linear portion 4b 1 which led to 5a, 4b 2, 5b 1, 5b 2 or small curvature arc section, processing center It is preferable to be symmetric with respect to Op4 and Op5 , that is, with respect to the center of the arc portions 4a and 5a. Further, it is preferable to perform the press working using a mold having a radius of a circular arc portion within a range of ⁇ 3.5 [%] with respect to a radius corresponding to the outer radius of the steel pipe. The reason will be described later.
  • a press die composed of upper mold 4 and the lower die 5 which, the shape of the open pipe S 2, the plate around the bottom of the U-shaped cross section A range of 20% or more of the width W (corresponding to a central angle ⁇ of 70 degrees or more) and a range of 10% or more of the plate width W from the plate width end (corresponding to a central angle of 35 degrees or more). but as a shape inscribed in a circular arc of the outer diameter and the same diameter or substantially the same diameter of the steel tube, the molded body S 1 pressing.
  • range open pipe S 2 is inscribed in the mold, the upper mold 4 side and the lower die 5 side, substantially the same
  • it is a size. That is, a range of 20% or more of the plate width W centered on the lowermost portion of the U-shaped section inscribed in an arc having the same diameter or substantially the same diameter as the outer diameter of the steel pipe is defined as A, and has the same diameter as the outer diameter of the steel pipe.
  • A a range of 20% or more of the plate width W centered on the lowermost portion of the U-shaped section inscribed in an arc having the same diameter or substantially the same diameter as the outer diameter of the steel pipe
  • B it is preferable to satisfy Expression (1). 2
  • the open pipe S 2 certainly is inscribed in a mold in a predetermined range, in order to obtain a good shape, as shown in FIG. 5, the press working In the U-shaped cross section, the formed body S 1 before being applied has an angle ⁇ between the tangent line TL 1 at the W / 2 portion, which is the center of the plate width, and the tangent lines TL 21 and TL 22 at the W / 4 portion. It is preferable that 11 , 12 be 35 degrees or more and less than 90 degrees.
  • the formed body S 1 before being subjected to the press working has angles ⁇ 21 , ⁇ 22 formed by the tangents TL 31 , TL 32 at the plate width end and the tangents TL 21 , TL 22 at the W / 4 part.
  • the angle is preferably 35 degrees or more and less than 90 degrees.
  • the sum of the angles ⁇ 11 and ⁇ 12 formed by the tangent line TL 1 and the tangent lines TL 21 and TL 22 and the tangent line It is preferable that the sum of the angles ⁇ 21 and ⁇ 22 formed by the tangents TL 21 and TL 22 with the tangents TL 31 and TL 32 are substantially the same.
  • the molded body S 1 to the lower mold 5, which is the other die so that one of the upper mold 4 is a mold with U-shaped open side of the molded body S 1 is opposite of the pair of molds the is placed, in the molded body S 1 by sandwiching the molded product S 1 by the upper mold 4 and the lower die 5 Upon performing press working, the upper mold 4 and the lower die 5, as follows It has a good machined surface.
  • the lower mold 5 in a state of placing the molded bodies S 1 to the lower mold 5, around the bottom of the U-shaped cross-section, 20% or more in the plate width W (center angle ⁇ is 70 above equivalent) without contact moldings S 1 except for the range of degrees, with the press working is completed, and a working surface not in contact with the open pipe S 2 to a portion of the lower die 5.
  • the upper mold 4 is opened with placing the shaped body S 1 to the lower mold 5 does not contact the forming body S 1, in a state where the pressing is completed, a portion of the upper mold 4 and a working surface that does not contact the tube S 2.
  • the molded body S 1 is preferably held in a U-posture with its U-shaped open side upwards. This is because, in part, working is easier when press working in this position. As another reason, if the case with its U-shaped open side downward, since the own weight of the molded body S 1 is applied to the plate width end portions of the molded article S 1, or the plate width ends, This is to avoid scratches on the mold, which can be avoided.
  • the unprocessed portion P is effectively deformed.
  • the bending moment is maximum at a position 90 degrees away from the position to which the pressing force is applied, and decreases as the position moves away from this position. Therefore, in order to cause sufficient plastic deformation in the unprocessed portion P, it is necessary to apply a pressing force to a portion separated by W / 4 ⁇ 0.07 W from the center of the unprocessed portion P toward the edge of the sheet width. preferable.
  • the center of the unprocessed portion P is provided at a portion including a position separated by W / 4 from the edge of the plate width, for the following reason. That is, as described above, the pressing force is desirably added at a site distant by W / 4 toward the plate width end portions from the center of the unprocessed portion P, and a molded body S 1 open pipe S 2 in step, the shape of the molded body S 1 changes, also changes the position for adding the contact position changes the pressing force of the upper mold 4 and the molded body S 1.
  • the unprocessed portion P if provided in the site containing the position separated by W / 4 from the strip width end in the molded body S 1, part of adding the pressing force is always the plate width end portions of the molded article S 1, The unprocessed portion P is most deformed. In this manner, the unprocessed portion P can be deformed by one pressing without changing the pressing position. Further, the raw portion P, preferably provided from the position i.e. the plate width ends of the molded body S 1 adds a pressing force in the range of W / 4 ⁇ 0.07W.
  • the unprocessed portion P from the plate width ends of the molded body S 1 It is preferable to provide a portion including a portion separated by W / 4.
  • the relationship between the restraint range and amount of opening of the seam gap G of the open pipe S 2 is a graph showing together with the press load.
  • the relationship between the opening amount and the restraining range shown in FIG. 6, and the press load, the both end portions of the open pipe S 2 performs expanded tube straightening by the expansion ratio 1 [%] after welding, the tensile strength 630 [ MPa], an outer diameter of 660.4 [mm], and a thickness of 40.0 [mm] when forming a steel pipe.
  • the angles ⁇ 11 and ⁇ 12 formed by the tangents at the W / 4 portion, which is a portion separated by / 4, are 75 degrees, and the angles ⁇ 21 , ⁇ 22 formed by the tangents at the plate width end and the tangents at the W / 4 portion.
  • the pressing amount, a distance connecting the W / 2 portion of the open pipe S 2 is rolling reduction in (O press is set to be equal to the diameter of the front pipe expansion, vertical size and diameter before pipe expansion To match). 6, the larger the constraint range, it can be seen that the amount of opening of the seam gap G of the open pipe S 2 becomes small.
  • Figure 7 is a diagram schematically showing a modified situation when the constraint range was molded open pipe S 2 with the upper mold 4 and the lower mold 5 of 0 degrees.
  • the upper mold 4 is in contact with only the both end portions of the molded article S 1
  • the lower die 5 is only the plate width central portion of the molded article S 1
  • the arc portions 4a and 5a are arcs having a diameter of 1.16 times the outer diameter of the steel pipe so that they contact each other. As shown in FIG.
  • Figure 8 is a graph showing the constrained range, the relationship between the roundness of the steel pipe before pipe expansion when closing the weld seam gap portion G of the open pipe S 2. From FIG. 8, when the constrained range is 60 degrees, the roundness is worse than when the constrained range is 0 degrees, but when the constrained range is increased, the roundness is improved and the constrained range is 70 degrees. It can be seen that the roundness is better in the above case than in the case where the constraint range is 0 degree. It can also be seen that the roundness is best when the constraint range is 100 degrees to 110 degrees.
  • FIG. 9 is a graph showing the relationship between the restraint range and the press load. From FIG. 9, it can be seen that the press load increases as the constraint range increases. For that reason, increasing the constraint range, restraint in an amount ranging opening of the seam gap G of the open pipe S 2 becomes small, minute the pressing load increases, the pressing equipment is increased in size, the desired opening amount is obtained It is desirable to reduce the range. For example, the press load, 90 [%] when the individual restraint range of the upper die 4 and the lower mold 5 for restraining the entire periphery of the shaped body S 1 in the upper mold 4 and the lower mold 5 is 180 degrees In order to set the range below, the constraint range may be set to 150 degrees or less.
  • Figure 10 is a graph showing the results of the amount of opening of the seam gap G of the open pipe S 2 with changes in individual restraining range of the upper die 4 and the lower mold 5.
  • 11, the upper mold 4 and with changes in individual restraining range of the lower die 5, roundness of the steel pipe before pipe expansion molded by closing the seam gap portion G of the open pipe S 2 by welding 7 is a graph showing the results of the above.
  • FIG. 12 is a graph showing the result of the press load when the respective constraint ranges of the upper mold 4 and the lower mold 5 are changed.
  • FIGS. 10 to 12 are directed to 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], similar to FIGS.
  • the horizontal axis indicates the average value of the constraint range of the upper mold 4 and the lower mold 5, and the symbol in the graph is changed for each constraint range of the lower mold 5.
  • “lower 60 degrees” means that the constraint range in the lower mold 5 is 60 degrees.
  • the difference between the upper and lower restraint ranges is 30 degrees, and the difference is 29% of the average value of the upper and lower restraint ranges.
  • the difference between the upper and lower restraint ranges is 30 degrees.
  • the difference between the upper and lower restraint ranges is as large as 40% of the average value of the upper and lower restraint ranges. The degree is slightly worse at 2.0 [%]. In this way, a good shape can be obtained by reducing the difference between the upper and lower restraint ranges.
  • the difference between the upper and lower restraint ranges is preferably less than 40 [%] of the average value of the upper and lower restraint ranges, and more preferably 30 [%] or less. It is preferable that the difference between the upper and lower restraint ranges is less than 30 degrees.
  • the relationship between the difference between the upper and lower restraint ranges and the average value of the upper and lower restraint ranges is, in other words, the plate width W centered on the lowermost part of the U-shaped cross section inscribed in an arc having the same or substantially the same diameter as the outer diameter of the steel pipe A is the range of 20% or more of A, and B is the total of the range of 10% or more of the width W from both ends of the plate width inscribed in an arc having the same or substantially the same diameter as the outer diameter of the steel pipe.
  • Formula (1) is preferably satisfied. 2
  • Figure 16 is a graph showing the results of the amount of opening of the seam gap G of the open pipe S 2 in the case of changing the arcuate portion radius of the upper die 4 and the lower mold 5.
  • FIG. 17 is a graph showing the result of the press load when the radius of the arc portion of the upper mold 4 and the lower mold 5 is changed.
  • the center angles of the arc portions 4a, 5a of the upper mold 4 and the lower mold 5 are set to 45 degrees, and the radius of the arc portions, which is the radius of the arc portions 4a, 5a, is changed.
  • This figure shows a case where a steel pipe having a strength of 630 MPa, an outer diameter of 660.4 [mm] and a pipe thickness of 40.0 [mm] is rolled down by an O-press so that the longitudinal diameter matches the diameter before the expansion.
  • the horizontal axis in FIGS. 16 and 17 is the ratio between the radius of the circular arc portion and the outer radius of the steel pipe (radius corresponding to the outer diameter of the steel pipe). When the radius of the arc portion is smaller than the outer radius of the steel pipe, the radius becomes smaller than 1.0.
  • the opening amount of the seam gap portion G becomes the smallest. ing.
  • the upper die 4 and the arcuate portion radius of the lower die 5 is greater than the steel pipe outer radius, deformation bent back at six portions and the vicinity thereof of the molding S 1 as shown in FIG. 7 occurs, As the radius of the arc portion of the upper mold 4 and the lower mold 5 increases, the opening amount of the seam gap G increases.
  • the radius of the arc portion of the upper die 4 and the lower die 5 is smaller than the outer radius of the steel pipe, a bending-back deformation occurs at the portion where the arc portions 4a, 5a of the upper die 4 and the lower die 5 are finished.
  • the opening amount of the seam gap G increases.
  • the radius of the arc portion of the upper die 4 and the lower die 5 is the same as the outer radius of the steel pipe.
  • the radius of the arc portion of the upper die 4 and the lower die 5 is the radius corresponding to the outer radius of the steel pipe.
  • the press load increases as the radius of the arc decreases, and especially when the radius of the arc is small, it is necessary to determine the radius in consideration of the load of the press. is there.
  • Example 1 A bevel was provided using an edge mirror, and a plate width W was processed to 1928 [mm].
  • Tables 1 and 2 show the shapes of the compacts A and B.
  • the first alphabets A and B in “No.” in Tables 1 and 2 indicate the shape of the molded body (molded bodies A and B). The combination of the constraint range of the mold 4 and the lower mold 5 is shown.
  • an unprocessed portion was provided with a width of 160 [mm] (W / 12) centering on the W / 4 part from the end of the plate width, and a tangent line at the end of the plate width and a W / 4 part.
  • the molded body A is shown in which the angles ⁇ 21 and ⁇ 22 formed by the tangents are 65 degrees, and the angles ⁇ 11 and ⁇ 12 formed by the tangents at the center of the plate width and the tangents at the W / 4 part are 73 degrees.
  • the molded body A After measuring, after forming a steel pipe having an outer diameter of 654 [mm] by welding seam gap portion G of the open pipe S 2, The diameter was measured at eight locations at a pitch of 22.5 degrees in the circumferential direction, and the difference between the maximum and the minimum of the diameter was determined. Tables 1 and 2 also show the mold shape (restriction range), press load, opening amount, and roundness. The roundness at this time is a number obtained by dividing the difference between the maximum and the minimum by the outer diameter of the steel pipe (the average value of all the measured values of the diameter).
  • the opening amount after the O-press exceeds 40 [mm]
  • the opening cannot be closed, and the opening is closed by another press machine.
  • full welding of the entire length of the seam gap portion G was performed.
  • 2.5 [%] was used as a guideline for acceptance before pipe expansion. This is because if the roundness before expansion is 2.5 [%] or less, the roundness after expansion can be a favorable value of 1.0 [%] or less.
  • the constraint range of the upper mold 4 and the lower mold 5 is a combination of 60 degrees and 90 degrees.
  • the opening amount is small, but the roundness is poor.
  • No. 1 in Table 1 where the average value of the constraint range is 60 degrees or less.
  • the opening amount is large.
  • the roundness could not be measured because the welded portion after welding the seam gap G was broken.
  • an unprocessed portion was provided with a width of 137 [mm] (W / 12) centered on the W / 4 part from the plate width end, and a tangent line at the plate width end and a W / 4 part in the W / 4 part.
  • the molded body A is shown in which the angles ⁇ 21 and ⁇ 22 formed by the tangents are 65 degrees, and the angles ⁇ 11 and ⁇ 12 formed by the tangents at the center of the plate width and the tangents at the W / 4 part are 72 degrees.
  • an unprocessed portion is provided with a width of 273 [mm] (W / 6) (twice the width of the condition A) centering on W / 4 from the edge of the sheet width,
  • the angles ⁇ 21 and ⁇ 22 formed by the tangent and the tangent at the W / 4 part are 59 degrees, and the angles ⁇ 11 and ⁇ 12 formed by the tangent at the center of the plate width and the tangent at the W / 4 part are 61 degrees.
  • Body B is shown.
  • the compacts A and B are symmetrical with respect to a straight line connecting the center of the plate width end and the plate width 1/2, and Tables 3 and 4 show the values of the plate width 1/2. Is shown.
  • the amount of reduction during the O-press was set such that the distance between the outer surface side of the W / 2 part and the outer surface side of the plate width end was 553 [mm].
  • the opening amount after the O-press exceeds 40 [mm]
  • the opening cannot be closed, and the opening is closed by another press machine.
  • full welding of the entire length of the seam gap portion G was performed.
  • 2.5 [%] was used as a guideline for acceptance before the pipe expansion was reduced to 1.0 [%] or less by pipe expansion.
  • No. 3 in Table 3 which is the range of the present invention example.
  • Nos. A1 to A7, A9, and A10 in Table 4 In B1 to B7, B9, and B10, the opening amount is small and the roundness is good. In particular, in the case where the constrained range is 90 degrees to 110 degrees, the roundness is 1.0% or less without performing tube expansion. Also, the smaller the average value of the constraint range, the smaller the press load.
  • condition A an unprocessed portion was provided with a width of 224 [mm] (W / 12) centered on the W / 4 part from the plate width end, and a tangent line at the plate width end and a W / 4 part
  • the molded body A is shown in which the angles ⁇ 21 and ⁇ 22 formed by the tangents are 73 degrees, and the angles ⁇ 11 and ⁇ 12 formed by the tangents at the center of the plate width and the tangents at the W / 4 part are 72 degrees.
  • condition B an unprocessed portion is provided with a width of 448 [mm] (W / 6) centered on W / 4 from the plate width end (twice the width of the condition A).
  • the molded body A After measuring, after forming a steel pipe having an outer diameter of 905 [mm] by welding seam gap portion G of the open pipe S 2, The diameter was measured at eight locations at a pitch of 22.5 degrees in the circumferential direction, and the difference between the maximum and the minimum of the diameter was determined.
  • Tables 5 and 6 also show the mold shape (restriction range), press load, opening amount, and roundness. The roundness at this time is a number obtained by dividing the difference between the maximum and the minimum by the outer diameter of the steel pipe.
  • the opening amount after the O-press exceeds 40 [mm]
  • the opening cannot be closed, and the opening is closed by another press machine.
  • full welding of the entire length of the seam gap portion G was performed.
  • 2.5 [%] was used as a guideline for acceptance before the pipe expansion was reduced to 1.0 [%] or less by pipe expansion.
  • No. 5 of Table 5 which is the range of the present invention example. Nos. A1 to A7, A9, and A10; In B1 to B7, B9, and B10, the opening amount is small and the roundness is good. In particular, in the case where the constrained range is 90 degrees to 110 degrees, the roundness is 1.0% or less without performing tube expansion. Also, the smaller the average value of the constraint range, the smaller the press load.
  • the constraint range of the upper mold 4 and the lower mold 5 is a combination of 60 degrees and 90 degrees.
  • the opening amount is small, but the roundness is poor.
  • the average value of the restraint range is 60 degrees or less.
  • the roundness could not be measured because the welded portion after welding the seam gap G was broken.
  • the press load and the roundness were substantially the same as those using the molded body A, but the opening amount was larger. Is getting smaller.
  • an unprocessed portion is provided with a width of W / 12 centered on the W / 4 part from the end of the plate width in accordance with the initial width W of the plate, and a tangent at the end of the plate width and W /
  • the angles ⁇ 21 and ⁇ 22 formed by the tangents in the four parts were set to 75 degrees
  • the angles ⁇ 11 and ⁇ 12 formed by the tangents in the center part of the plate width and the tangents in the W / 4 part were set to 75 degrees.
  • the distance between the outer surface side of the W / 2 part and the outer surface side of the plate width end was reduced so as to be a value corresponding to the initial plate width W as shown in Table 7.
  • Table 7 shows the outer diameter of the steel pipe after O-press reduction.
  • the ratio of the circular arc radius to the outer radius of the steel pipe is 1.00.
  • the opening amount that can be closed by the welding machine used in Example 1 is 40 [mm] or less.
  • D2 to D10, and the ratio of the radius of the arc to the outer radius of the steel pipe is 0.96 to 1.04.
  • the opening amount of 50 [mm] at which the welded portion did not break was the same as in No. 7 of Table 7.
  • D2 to D10, and the ratio of the radius of the arc to the outer radius of the steel pipe is 0.96 to 1.04.
  • the opening amount at which the seam gap G can be closed by welding and the opening amount at which the welded portion does not break vary depending on the welding equipment and the welding method, but the radius of the arc portion of the upper mold 4 and the lower mold 5 is different. Is 0.96 to 1.04 of the outer radius of the steel pipe.
PCT/JP2018/034145 2018-09-14 2018-09-14 鋼管の製造方法及びプレス金型 WO2020054051A1 (ja)

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RU2021110038A RU2769596C1 (ru) 2018-09-14 2018-09-14 Способ изготовления стальной трубы и матрица
PCT/JP2018/034145 WO2020054051A1 (ja) 2018-09-14 2018-09-14 鋼管の製造方法及びプレス金型
KR1020217006550A KR102425607B1 (ko) 2018-09-14 2018-09-14 강관의 제조 방법 및 프레스 금형
JP2019547161A JP6791397B2 (ja) 2018-09-14 2018-09-14 鋼管の製造方法及びプレス金型
BR112021004322-5A BR112021004322A2 (pt) 2018-09-14 2018-09-14 método de produção de tubo de aço e molde de prensagem
CN201880097036.2A CN112638558B (zh) 2018-09-14 2018-09-14 钢管的制造方法及冲压模具
EP18933413.9A EP3851220A4 (en) 2018-09-14 2018-09-14 STEEL PIPE MANUFACTURING PROCESS AND PRESS DIE

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CN112638558B (zh) 2022-12-16
EP3851220A4 (en) 2021-09-22
EP3851220A1 (en) 2021-07-21
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JP6791397B2 (ja) 2020-11-25
BR112021004322A2 (pt) 2021-07-20

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