WO2023238864A1 - Joint fileté pour tuyau en acier - Google Patents

Joint fileté pour tuyau en acier Download PDF

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Publication number
WO2023238864A1
WO2023238864A1 PCT/JP2023/021005 JP2023021005W WO2023238864A1 WO 2023238864 A1 WO2023238864 A1 WO 2023238864A1 JP 2023021005 W JP2023021005 W JP 2023021005W WO 2023238864 A1 WO2023238864 A1 WO 2023238864A1
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WIPO (PCT)
Prior art keywords
pin
box
tapered region
sealing surface
thread
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PCT/JP2023/021005
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English (en)
Japanese (ja)
Inventor
景太 井瀬
賢 栗生
琢也 辻村
優嘉 佐々木
崇夫 倉西
Original Assignee
日本製鉄株式会社
バローレック・オイル・アンド・ガス・フランス
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Application filed by 日本製鉄株式会社, バローレック・オイル・アンド・ガス・フランス filed Critical 日本製鉄株式会社
Publication of WO2023238864A1 publication Critical patent/WO2023238864A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
    • F16L15/04—Screw-threaded joints; Forms of screw-threads for such joints with additional sealings

Definitions

  • This type of threaded joint for steel pipes is broadly divided into coupling type and integral type.
  • a coupling type one of the pair of pipe materials to be connected is a steel pipe, and the other pipe material is a coupling.
  • male threads are provided on the outer periphery of both ends of the steel pipe, and female threads are provided on the inner periphery of both ends of the coupling. Then, the male thread of the steel pipe is screwed into the female thread of the coupling, thereby fastening and connecting the two.
  • the pair of pipes to be connected are both steel pipes, and separate couplings are not used.
  • a male thread is provided on the outer periphery of one end of the steel pipe, and a female thread is provided on the inner periphery of the other end. Then, the male threaded portion of one steel pipe is screwed into the female threaded portion of the other steel pipe, thereby fastening and connecting the two.
  • the joint portion at the end of the tube in which the male thread is formed is called a pin because it includes an element that is inserted into the female thread.
  • the joint portion at the end of the tube in which the female thread is formed is called a box because it includes an element for receiving the male thread.
  • Threaded joints for oil country tubular goods exhibit high sealing performance at the sealing part.
  • the diameter of the seal on the pin is larger than the diameter of the seal on the box. Therefore, in the fastened state, both seal portions fit into each other and come into close contact with each other to form an interference fit, forming a seal portion through metal contact.
  • the difference between the pin seal diameter and the box seal diameter is called the "seal interference". The larger the amount of seal interference, the higher the seal contact force, and the better the sealing performance.
  • At least one of the pin and the box may be made thinner.
  • An example of a threaded joint in which the pin and/or box are made thinner is a so-called slim type.
  • the slim type threaded joint has an outer diameter that is approximately the same as the outer diameter of the oil country tubular body. Since the slim type threaded joint has a thinner wall, it is difficult to ensure the wall thickness of the seal portion and the area of the shoulder surface.
  • Patent Document 1 discloses a tubular threaded connection.
  • the tubular threaded connection has a tubular male end (pin) and a tubular female end (box).
  • the tubular male end includes an outer male sealing surface, an inner male sealing surface, outer male threads, inner male threads, and a male shoulder located between the outer male threads and the inner male threads.
  • the tubular female end has an outer female seal surface that corresponds to the outer male seal surface, an inner female seal surface that corresponds to the inner male seal surface, an outer female thread that meshes with the outer male thread, an inner female thread that meshes with the inner male thread, and a male shoulder. and a female shoulder that contacts the.
  • Patent Document 1 discloses that the outer female thread and the inner female thread that engage with the outer male thread and the inner male thread, respectively, are tapered along the same taper angle, and the pitch and lead of the load surface and the insertion surface are exactly the same. There is.
  • Patent Document 2 discloses a threaded joint for steel pipes.
  • a threaded joint for steel pipes consists of a tubular pin and a tubular box.
  • the pin includes, in order from the tip end of the pin toward the tube body side, an inner sealing surface, an inner male threaded portion, a shoulder portion, an outer male threaded portion, and an outer sealing surface.
  • the box includes, in order from the tube body side to the distal end side of the box, an inner sealing surface, an inner female threaded portion, a shoulder portion, an outer female threaded portion, and an outer sealing surface.
  • An object of the present disclosure is to provide a threaded joint for steel pipes that can improve seizure resistance and manufacturing cost.
  • the threaded joint for steel pipes may include a tubular pin and a tubular box into which the pin is screwed and fastened to the pin.
  • the pin is located between an internal sealing surface formed at the tip of the pin, an internal sealing surface of the pin, and the steel pipe body, and a male thread formed on the outer peripheral surface of the pin, and a connection between the steel pipe main body and the male thread. and a pin outer sealing surface formed therebetween.
  • the box has an internal sealing surface that faces the internal sealing surface of the pin and contacts the internal sealing surface of the pin when the pin and box are fastened, and a female thread that corresponds to the external thread and is formed on the internal peripheral surface of the box.
  • the male thread has a first tapered region located between the pin inner sealing surface and the pin outer sealing surface, and a first tapered region located between the pin inner sealing surface and the first tapered region, and having a slope smaller than the first tapered region. and a second tapered region.
  • the female thread has a third tapered region located between the box inner sealing surface and the box outer sealing surface, and a third tapered region located between the box outer sealing surface and the third tapered region, and has a slope smaller than the third tapered region. and a fourth tapered region.
  • the threads included in the second tapered region may have a wider width than the threads included in the first tapered region.
  • the threads included in the fourth tapered region may have a width wider than the thread width of the threads included in the third tapered region.
  • the insertion surface pitch of the male thread and the female thread may be constant.
  • FIG. 1 is a longitudinal sectional view showing how the threads of a threaded joint for steel pipes are cut.
  • FIG. 2 is a longitudinal sectional view showing the threaded joint for steel pipes according to the first embodiment.
  • FIG. 3 is an enlarged sectional view of the threaded joint for steel pipes shown in FIG. 2.
  • FIG. 4 is a longitudinal cross-sectional view showing how the threads of the threaded joint for steel pipes shown in FIG. 2 are cut.
  • FIG. 5 is a longitudinal sectional view showing a threaded joint for steel pipes according to a second embodiment.
  • FIG. 6 is a longitudinal sectional view showing a threaded joint for steel pipes according to a third embodiment.
  • the present inventors have determined that the bottom surface of the male thread at the tip of the pin and the bottom surface of the female thread at the tip of the box are connected to the steel pipe body. It was considered to make the taper parallel to the tube axis, or to make the slope of the taper of the thread bottom surface at the tip of the male thread and the tip of the female thread smaller than the slope of the taper of the male thread and the female thread excluding these tips. This makes it possible to increase the thickness of the pin inner sealing surface and the box outer sealing surface to improve rigidity and improve sealing performance.
  • joint efficiency of the slim type threaded joint is less than 1.
  • Joint efficiency is the ratio of the tensile strength of the joint part to the tensile strength of the steel pipe body, and the cross section of the joint part where the area that can withstand tensile load is the smallest in the connected state (generally referred to as the "dangerous cross section"). It is defined as the area of / cross-sectional area of the oil country tubular body.
  • the load surface pitch and the insertion surface pitch be the same.
  • the insertion surface pitch changes between the tapered region with the slope ⁇ and the taper region with the slope ⁇ . That is, compared to the case where the slope ⁇ and the slope ⁇ are constant, the insertion surface moves by the difference ⁇ in the figure so that the thread width becomes wider in the tapered region of the slope ⁇ . If the width of the thread in the tapered region with the slope ⁇ becomes wide as described above, the insertion surfaces come into excessive contact with each other during the process of fastening the pin and the box, and seizure is likely to occur.
  • the present inventors have newly discovered that when the slope ⁇ and the slope ⁇ are different, if the insertion surface pitch is kept constant, it is possible to improve seizure resistance and manufacturability while ensuring sealing performance. . Based on this knowledge, the present inventors invented the following threaded joint for steel pipes.
  • the threaded joint for steel pipes may include a tubular pin and a tubular box into which the pin is screwed and fastened to the pin.
  • the pin is located between an internal sealing surface formed at the tip of the pin, an internal sealing surface of the pin, and the steel pipe body, and a male thread formed on the outer peripheral surface of the pin, and a connection between the steel pipe main body and the male thread. and a pin outer sealing surface formed therebetween.
  • the box has an internal sealing surface that faces the internal sealing surface of the pin and contacts the internal sealing surface of the pin when the pin and box are fastened, and a female thread that corresponds to the external thread and is formed on the internal peripheral surface of the box.
  • the male thread has a first tapered region located between the pin inner sealing surface and the pin outer sealing surface, and a first tapered region located between the pin inner sealing surface and the first tapered region, and having a slope smaller than the first tapered region. and a second tapered region.
  • the female thread has a third tapered region located between the box inner sealing surface and the box outer sealing surface, and a third tapered region located between the box outer sealing surface and the third tapered region, and has a slope smaller than the third tapered region. and a fourth tapered region.
  • the threads included in the second tapered region may have a wider width than the threads included in the first tapered region.
  • the threads included in the fourth tapered region may have a width wider than the thread width of the threads included in the third tapered region.
  • the insertion surface pitch of the male thread and the female thread may be constant.
  • the threads included in the second taper region have a width wider than the thread width of the threads included in the first taper region, and the threads included in the fourth taper region have a width larger than that of the threads included in the first taper region. It has a width wider than the thread width of the included threads, and the insertion surface pitch of the male thread and the female thread is constant. That is, the load surface pitch of the male thread and the female thread is changing.
  • the load surface pitch of the threads included in the second and fourth tapered regions is smaller than the load surface pitch of the threads included in the first and third regions.
  • the slopes of the second and fourth tapered regions include cases where the slopes are parallel to the tube axis CL (or a straight line parallel thereto).
  • a threaded joint for steel pipes may include a tubular pin and a tubular box into which the pin is screwed and fastened to the pin.
  • the pin is located between the internal sealing surface formed at the tip of the pin, the internal sealing surface of the pin, and the steel pipe body, and the internal male thread formed on the outer peripheral surface of the pin, and the internal male thread between the steel pipe main body and the internal male thread.
  • the pin may include an outer male thread located therebetween and formed on the outer peripheral surface of the pin, and a pin intermediate sealing surface formed between the inner male thread and the outer male thread.
  • the box has an inner seal surface formed on the inner peripheral surface of the box that faces the inner seal surface of the pin and that contacts the inner seal surface of the pin when the pin and box are fastened, and an inner male thread that corresponds to the inner male thread.
  • An outer female thread formed on the inner peripheral surface of the box that corresponds to the female thread and the outer male thread, and a box intermediate seal that faces the pin intermediate seal surface and comes into contact with the pin intermediate seal surface when the pin and box are fastened. may include a surface.
  • the internal male thread has a fifth tapered region located between the pin internal sealing surface and the pin intermediate sealing surface, and a fifth tapered region located between the pin internal sealing surface and the fifth tapered region, and has a slope smaller than the fifth tapered region. and a sixth tapered region.
  • the external male thread includes a seventh tapered region located between the pin intermediate sealing surface and the steel pipe body, and a seventh tapered region located between the pin intermediate sealing surface and the seventh tapered region and having a smaller slope than the seventh tapered region. 8 tapered regions.
  • the internal female thread has a ninth tapered region located between the box inner sealing surface and the box intermediate sealing surface, and a ninth tapered region located between the box intermediate sealing surface and the ninth tapered region, which has a smaller slope than the ninth tapered region. and a tenth tapered region.
  • the external female thread has an 11th tapered region located between the box intermediate sealing surface and the top end of the box, and a tapered region located between the top end of the box and the 11th taper region, which has a smaller slope than the 11th taper region. and a twelfth tapered region.
  • the threads included in the sixth and eighth tapered regions may each have a wider width than the threads included in the fifth and seventh tapered regions.
  • the threads included in the tenth and twelfth tapered regions may have a wider width than the threads included in the ninth and eleventh tapered regions.
  • the insertion surface pitch of the internal male thread and the internal female thread may be constant.
  • the insertion surface pitch of the outer male thread and the outer female thread may be constant. Thereby, it is possible to improve seizure resistance and manufacturability in the process of fastening the pin and box.
  • the outer sealing surface of the box that sometimes contacts the outer sealing surface of the pin, the inner female thread formed on the inner circumferential surface of the box corresponding to the inner male thread, and the outer sealing surface formed on the inner circumferential surface of the box corresponding to the outer male thread.
  • the box may include an internal thread and a box intermediate shoulder surface that faces the pin intermediate shoulder surface and contacts the pin intermediate shoulder surface when the pin and box are fastened.
  • the internal male thread has a fifth tapered region located between the pin internal sealing surface and the pin intermediate shoulder surface, and a fifth tapered region located between the pin internal sealing surface and the fifth tapered region, which has a smaller slope than the fifth tapered region. and a sixth tapered region.
  • the male and female threads may include a fully threaded portion having a threaded top surface and a threaded bottom surface.
  • the threaded top surface and threaded bottom surface may be parallel to the pipe axis of the steel pipe body.
  • the threaded joint for steel pipes may be an integral threaded joint.
  • the threaded joint for steel pipes may have an outer diameter of 105% or less of the steel pipe body.
  • the threaded joint 1 for steel pipes according to the first embodiment is a slim threaded joint, which includes a tubular pin 10 and a tubular box into which the pin 10 is screwed and fastened to the pin 10. 20.
  • the threaded joint 1 for steel pipes according to the present disclosure can be more suitably used in the slim-type threaded joint 1 for steel pipes.
  • the slim type threaded joint 1 for steel pipes has, for example, an outer diameter of 105% or less of the steel pipe main body 2.
  • the pin 10 is provided at the pipe end of one of the steel pipe main bodies 2.
  • the pin 10 includes a tapered external thread 11, an internal pin sealing surface 12, an external pin sealing surface 13, and an internal pin shoulder surface 14.
  • the male thread 11 includes a tapered region 111 and a tapered region 112.
  • Tapered region 112 is formed on the tip side of pin 10 .
  • Tapered region 111 is formed between region 112 and pin outer sealing surface 13 .
  • Tapered region 111 has a taper gradient ⁇ 1.
  • Tapered region 112 has a slope ⁇ 1 smaller than slope ⁇ 1 of tapered region 111.
  • the slope ⁇ 1 of the tapered region 112 is smaller than the taper slope ⁇ 1.
  • the slope ⁇ 1 includes a case where the slope ⁇ 1 is parallel to the tube axis CL (or a straight line parallel thereto).
  • the male thread 11 is a trapezoidal thread, as shown in FIG.
  • the male thread 11 has a thread bottom surface 1111, a thread top surface 1112, an insertion surface 1113, and a load surface 1114.
  • Insertion surface 1113 has a positive flank angle.
  • Loading surface 1114 has a negative flank angle.
  • the absolute value of the flank angle of the insertion surface 1113 is greater than the absolute value of the flank angle of the load surface 1114.
  • the flank angle refers to the angle between a straight line perpendicular to the tube axis CL and the insertion surface or load surface in the longitudinal section of the threaded joint 1 for steel pipes.
  • the flank angle of the insertion surface 1113 the positive direction is counterclockwise in the drawing.
  • the insertion surface 1113 is inclined such that the outer circumferential portion is located further back in the tube axis direction than the inner circumferential portion.
  • the flank angle of the load surface 1114 the counterclockwise direction in the figure is the negative direction. Therefore, the load surface 1114 is inclined such that the outer circumferential portion is located further back in the tube axis direction than the inner circumferential portion.
  • the thread bottom surface 1111 and the thread top surface 1112 are parallel to the thread taper in a longitudinal cross-sectional view.
  • the thread bottom surface 1111 and the thread top surface 1112 may be parallel to the tube axis CL in a longitudinal cross-sectional view.
  • the box 20 is provided at the pipe end of the other steel pipe main body 2.
  • the box 20 includes a tapered internal thread 21, an inner box sealing surface 22, an outer box sealing surface 23, and an inner box shoulder surface 24.
  • the female thread 21 corresponds to the male thread 11 and is formed on the inner peripheral surface of the box 20.
  • the in-box shoulder surface 24 corresponds to the in-pin shoulder surface 14 and is formed on the rear end side of the box 20.
  • the in-box shoulder surface 24 is an annular surface substantially perpendicular to the tube axis CL.
  • the in-box shoulder surface 24 contacts the in-pin shoulder surface 14 when the pin 10 and box 20 are fastened.
  • the box inner sealing surface 22 corresponds to the pin inner sealing surface 12 and is formed on the inner peripheral surface of the box 20.
  • the box inner sealing surface 22 contacts the pin inner sealing surface 12 when the pin 10 and the box 20 are fastened.
  • the box outer sealing surface 23 corresponds to the pin outer sealing surface 13 and is formed on the inner peripheral surface of the box. The box outer sealing surface 23 contacts the pin outer sealing surface 13 when the pin 10 and the box 20 are fastened.
  • the slopes ⁇ 2 and ⁇ 2 of the taper are the straight line connecting the bottom surface of the female thread 21 and the pipe axis CL (or a straight line parallel to this) in the longitudinal section of the pin 10 including the pipe axis CL. ) is the gradient between
  • the taper gradients ⁇ 2 and ⁇ 2 are determined at the intersection of the extension line of the bottom surface of the female thread 21 and the extension line of the load surface in the longitudinal section of the pin 10 including the tube axis CL. This is the slope between the straight line connecting the lines and the tube axis CL (or a straight line parallel to this).
  • the female thread 21 is a trapezoidal thread, as shown in FIG.
  • the female thread 21 has a thread bottom surface 2111, a thread top surface 2112, an insertion surface 2113, and a load surface 2114.
  • Insertion surface 2113 has a positive flank angle.
  • Loading surface 2114 has a negative flank angle.
  • the absolute value of the flank angle of the insertion surface 2113 is greater than the absolute value of the flank angle of the load surface 2114.
  • the positive direction is counterclockwise in the figure. Therefore, the insertion surface 2113 is inclined such that the outer circumferential portion is located further forward in the tube axis direction than the inner circumferential portion.
  • the load surface 2114 is inclined such that the outer circumferential portion is located further forward in the tube axis direction than the inner circumferential portion.
  • the thread bottom surface 2111 and the thread top surface 2112 are parallel to the thread taper in a longitudinal cross-sectional view.
  • the thread bottom surface 2111 and the thread top surface 2112 may be parallel to the tube axis CL in a longitudinal cross-sectional view.
  • the thread bottom surface 1111 of the male thread 11 and the thread top surface 2112 of the female thread 21 come into contact at the fully threaded portion of the male thread 11 and the female thread 21, and the load surface 1114 of the male thread 11 and the female thread 21 load surfaces 2114 contact each other.
  • the insertion surface 1113 of the male thread 11 and the insertion surface 2113 of the female thread 21 face each other with a gap between them, and the top surface 1112 of the male thread 11 and the bottom face 2111 of the female thread 21 face each other with a gap between them.
  • the insertion surface pitch of the male thread 11 and the insertion surface pitch of the female thread 21 are constant.
  • the insertion surface pitch becomes constant.
  • the load surface of the male screw 11 moves by the difference ⁇ in the figure so that the thread width of the male screw 11 becomes wider. That is, the load surface pitch LP ⁇ and the load surface pitch LP ⁇ change between the slopes ⁇ 1 and ⁇ 1.
  • the thread width of the thread included in the tapered region 112 is wider than the thread width of the tapered region 111 because the gradient ⁇ 1 is smaller than the gradient ⁇ 1. That is, since the insertion surface pitch is constant, the thickness increases at the load surface 1114 of the male screw 11. As a result, an amount of interference in the tube axis direction is introduced between the load surface 1114 of the male thread 11 and the load surface 2114 of the female thread 21 in the tapered region 112 and the tapered region 212.
  • the dangerous cross section of the pin 10 is the threaded end on the one steel pipe main body 2 side
  • the dangerous cross section of the box 20 is the threaded end on the tip side of the pin 10. be. If sufficient engagement is not obtained between the male thread 11 and the female thread 21 in these dangerous cross-sections, the applied tensile load will not be reliably transmitted to the pin 10 and the box 20, and neither the pin 10 nor the box 20 will be properly engaged. Otherwise, an excessive load may be applied, leading to a decrease in tensile strength.
  • the load surfaces of the tapered region 112 and the tapered region 212 are in strong contact with each other. That is, the contact between the load surfaces of the male thread 11 and the female thread 12 at these critical cross-sections becomes stronger. Thereby, the load surfaces can be reliably engaged with each other at these critical cross-sections, and the tensile load can be reliably transmitted to the pin 10 and the box 20. That is, the tensile strength can be improved.
  • the threaded joint 1 for steel pipes according to the second embodiment is a so-called two-stage thread.
  • the threaded joint 1 for steel pipes includes a pin 10 and a box 20.
  • the pin 10 has an inner male thread 11a, an outer male thread 11b, and a pin intermediate sealing surface 15.
  • the pin intermediate sealing surface 15 is formed on the outer peripheral surface of the pin 10 between the inner male thread 11a and the outer male thread 11b.
  • the internal male thread 11a is formed on the outer peripheral surface of the pin 10 between the pin internal sealing surface 12 and the pin intermediate sealing surface 15.
  • the external male thread 11b is formed on the outer peripheral surface of the pin 10 between the pin intermediate sealing surface 15 and the steel pipe body 2.
  • the pin outer seal surface 13 is not formed, but the pin outer seal surface 13 is formed on the outer peripheral surface of the pin 10 between the outer male thread 11b and the steel pipe main body 2. may be formed.
  • the box 20 has an inner female thread 21a, an outer female thread 21b, and a box intermediate sealing surface 25.
  • the internal female thread 21a corresponds to the internal male thread 11a and is formed on the inner peripheral surface of the box 20.
  • the outer female thread 21b corresponds to the outer male thread 11b and is formed on the inner peripheral surface of the box 20.
  • the box intermediate sealing surface 25 corresponds to the pin intermediate sealing surface 15 and is formed on the inner peripheral surface of the box 20. When the pin 10 and the box 20 are fastened, the box intermediate sealing surface 25 contacts the pin intermediate sealing surface 15.
  • a box outer sealing surface 23 corresponding to the pin outer sealing surface 13 may be formed.
  • the internal male thread 11a includes a tapered region 111a and a tapered region 112a.
  • Tapered region 112a is formed on the tip side of pin 10.
  • Tapered region 111a is formed between tapered region 112a and pin intermediate sealing surface 15.
  • the tapered region 111a has a taper gradient ⁇ 1.
  • Tapered region 112a has a slope ⁇ 1 smaller than slope ⁇ 1.
  • the slope ⁇ 1 is smaller than the taper slope ⁇ 1.
  • the slope ⁇ 1 includes a case where the slope ⁇ 1 is parallel to the tube axis CL (or a straight line parallel thereto).
  • the internal female thread 21a includes a tapered region 211a and a tapered region 212a.
  • Tapered region 212a is formed on the front end side of box 20.
  • Tapered region 211a is formed between tapered region 212a and box inner sealing surface 22.
  • the tapered region 211a has a taper gradient ⁇ 2.
  • Tapered region 212a has a slope ⁇ 2 smaller than slope ⁇ 2.
  • the slope ⁇ 2 is smaller than the slope ⁇ 2.
  • the slope ⁇ 2 includes a case where the slope ⁇ 2 is parallel to the tube axis CL (or a straight line parallel thereto).
  • the external male thread 11b includes a tapered region 111b and a tapered region 112b.
  • Tapered region 112b is formed on the pin intermediate seal surface 15 side.
  • Tapered region 111b is formed between tapered region 112b and steel pipe main body 2.
  • the tapered region 111b has a taper gradient ⁇ 3.
  • Tapered region 112b has a slope ⁇ 3 smaller than slope ⁇ 3.
  • the slope ⁇ 3 is smaller than the slope ⁇ 3.
  • the slope ⁇ 3 includes a case where the slope ⁇ 3 is parallel to the tube axis CL (or a straight line parallel thereto).
  • the external female thread 21b includes a tapered region 211b and a tapered region 212b.
  • the tapered region 212b is formed on the front end side of the box 20.
  • Tapered region 211b is formed between tapered region 212b and box intermediate sealing surface 25.
  • Tapered region 211b has a taper gradient ⁇ 4.
  • Tapered region 212b has a slope ⁇ 4 smaller than slope ⁇ 4.
  • the insertion surface pitch of the inner male thread 11a and the inner female thread 21a is constant, and the insertion surface pitch of the outer male thread 11b and the outer female thread 21b is also constant.
  • seizure can be suppressed in the process of fastening the pin 10 and the box 20.
  • the wall thickness on the load surface of the thread increases. Thereby, tensile strength can be improved.
  • the threaded joint 1 for steel pipes includes a pin 10 and a box 20.
  • the pin 10 has a pin intermediate shoulder surface 16, a pin outer seal surface 13, and a pin groove portion 17.
  • the pin intermediate shoulder surface 16 is formed on the outer peripheral surface of the pin 10 between the inner male thread 11a and the outer male thread 11b.
  • the pin intermediate shoulder surface 16 is an annular surface substantially perpendicular to the tube axis CL.
  • the pin outer sealing surface 13 is formed on the outer circumferential surface of the pin 10 between the outer male thread 11b and one steel pipe main body 2.
  • the pin groove 17 is an annular groove formed on the outer peripheral surface of the pin 10, facing the tapered region 212b of the female thread 21b.
  • the pin groove portion 17 is spaced apart from the tapered region 212b of the female thread 21b and does not come into contact with the tapered region 212b when the pin 10 and box 20 are fastened. That is, a gap is provided between the pin groove portion 17 and the tapered region 212b of the female thread 21b.
  • the slope ⁇ 4 of the tapered region 212b is smaller than the taper slope ⁇ 4 of the tapered region 211b, so the thread width of the thread included in the tapered region 212b is the thread width of the thread included in the tapered region 211b.
  • the box 20 has a box intermediate shoulder surface 26, a box outer sealing surface 23, and a box groove 27.
  • the box intermediate shoulder surface 26 corresponds to the pin intermediate shoulder surface 16 and is formed on the inner peripheral surface of the box 20.
  • the box intermediate shoulder surface 26 is an annular surface substantially perpendicular to the tube axis CL. Box intermediate shoulder surface 26 contacts pin intermediate shoulder surface 16 when pin 10 and box 20 are fastened.
  • the box outer sealing surface 23 corresponds to the pin outer sealing surface 13 and is formed on the inner peripheral surface of the box 20. The box outer sealing surface 23 contacts the pin outer sealing surface 13 when the pin 10 and the box 20 are fastened.
  • the box groove 27 is an annular groove formed on the outer peripheral surface of the box 20, facing the tapered region 112a of the internal male thread 11a.
  • the box groove portion 27 is spaced apart from the tapered region 112a of the internal male screw 11a and does not come into contact with the tapered region 112a when the pin 10 and box 20 are fastened. That is, a gap is provided between the box groove portion 27 and the tapered region 112a of the male thread 11a.
  • the thread width of the thread included in the tapered region 112a is smaller than the thread width of the thread included in the tapered region 111a. It becomes wider.
  • the thread width of the thread included in the tapered region 212a is smaller than the thread width of the thread included in the tapered region 111a. It becomes wider. Therefore, an amount of interference in the tube axis direction is introduced between the load surface of the thread included in the tapered region 212a and the load surface of the thread included in the tapered region 111a.
  • the thread width of the thread included in the tapered region 112b is the thread width of the thread included in the tapered region 211b. becomes wider than Therefore, an amount of interference in the tube axis direction is introduced between the load surface of the thread included in the tapered region 112b and the load surface of the thread included in the tapered region 211b. The amount of interference increases as the pin intermediate shoulder surface 16 and the box intermediate shoulder surface 26 are approached.
  • the pin 10 includes a pin intermediate dangerous cross section PSSC1 and a pin dangerous cross section PSSC2.
  • Box 20 includes a box intermediate dangerous section BCCS1 and a box dangerous section BCCS2.
  • the critical cross section is the cross section of the joint portion where the area that can withstand tensile load is the smallest in the fastened state.
  • the pin intermediate dangerous cross section PSSC1 is located near the end of the internal male thread 11a on the pin intermediate shoulder 16 side.
  • the pin dangerous cross section PSSC2 is located near the end of the external male thread 11b on the pin external sealing surface 13 side.
  • the box intermediate dangerous cross section BSSC1 is located near the end of the external female thread 21b on the box intermediate shoulder surface 26 side.
  • the box dangerous cross section BSSC2 is located near the end on the box inner sealing surface 22 side.
  • the threaded joint 1 for steel pipes according to the present disclosure can also be applied to coupling-type or integral-type threaded joints 1 for steel pipes.
  • the threaded joint 1 for steel pipes of the present disclosure can achieve particularly great effects in slim-type threaded joints 1 for steel pipes where strict restrictions are imposed on the outer diameter dimension.
  • the steel pipe threaded joint 1 according to the present disclosure can be suitably applied to a so-called dope-free threaded joint.
  • a dope-free threaded joint is a threaded joint in which dope is not applied when the pin 10 and box 20 are fastened, and a solid lubricant film or semi-solid lubricant film is preliminarily formed on either the pin 10 or the box 20 before fastening. It is.
  • Dope-free threaded joints are repeatedly fastened and dismantled without reapplying dope. Therefore, excellent seizure resistance is required. Therefore, the threaded joint 1 for steel pipes of the present disclosure, which has excellent seizure resistance, can be suitably applied to dope-free threaded joints.
  • Table 1 shows the analysis results in the first and second analyses. Note that specimens 1 and 2 are comparative examples, and specimen 3 is an example. Further, in Table 1, the contact pressure refers to the maximum contact pressure applied to the threaded portion during stabbing.
  • specimen 1 is evaluated as “B” because it has poor manufacturability
  • specimens 2 and 3 which only need to be cut to align either the load surface pitch or the insertion surface pitch, are evaluated as “B” because they have excellent manufacturability.
  • Rated "A" is evaluated.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Non-Disconnectible Joints And Screw-Threaded Joints (AREA)

Abstract

L'invention concerne un joint fileté qui est destiné à un tuyau en acier et qui peut améliorer les performances de résistance au grippage et la fabricabilité. Un joint fileté 1 destiné à un tuyau en acier comprend : une broche 10 ; et une boîte 20. La broche 10 comprend une vis mâle 11, une surface d'étanchéité de broche interne 12, et une surface d'étanchéité de broche externe 13. La boîte 20 a une vis femelle 12, une surface d'étanchéité de boîte interne 12 et une surface d'étanchéité de boîte externe 23. La vis mâle 11 comprend une région conique 111 positionnée sur le côté de surface d'étanchéité de broche externe 13, et une région conique 112 positionnée sur le côté de surface d'étanchéité de broche interne 11. Le gradient β1 de la région conique 112 est inférieur au gradient α1 de la région conique 111. Le pas de surface d'insertion des filetages de vis inclus dans la vis mâle 112 est constant. Les filetages de vis inclus dans la région conique 112 ont une largeur de filetage de vis plus large que celle des filetages de vis inclus dans la région conique 111.
PCT/JP2023/021005 2022-06-07 2023-06-06 Joint fileté pour tuyau en acier WO2023238864A1 (fr)

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JP2022092298 2022-06-07
JP2022-092298 2022-06-07

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WO2023238864A1 true WO2023238864A1 (fr) 2023-12-14

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4588213A (en) * 1983-10-05 1986-05-13 Thread Technology International, Inc. Threaded pipe connection
JPH0280886A (ja) * 1988-09-14 1990-03-20 Nippon Steel Corp シール面圧保持機能の優れた油井管用ネジ継手
JP2005523404A (ja) * 2002-04-19 2005-08-04 ハイドリル・カンパニー 特に半径方向に塑性的に拡張可能な導管のためのねじ結合構造
JP2008215473A (ja) * 2007-03-02 2008-09-18 Sumitomo Metal Ind Ltd 鋼管用ねじ継手
WO2018135536A1 (fr) * 2017-01-18 2018-07-26 新日鐵住金株式会社 Raccord fileté
WO2021013646A1 (fr) * 2019-07-19 2021-01-28 Vallourec Oil And Gas France Raccord fileté pour colonne de tubage d'un puits de pétrole
JP6916277B2 (ja) * 2017-05-15 2021-08-11 日本製鉄株式会社 鋼管用ねじ継手
JP2022008003A (ja) * 2020-03-26 2022-01-13 株式会社NejiLaw 油井管連結構造及び油井管
WO2022090034A1 (fr) * 2020-10-28 2022-05-05 Vallourec Oil And Gas France Connexion filetée autobloquante partiellement en prise sans blocage

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4588213A (en) * 1983-10-05 1986-05-13 Thread Technology International, Inc. Threaded pipe connection
JPH0280886A (ja) * 1988-09-14 1990-03-20 Nippon Steel Corp シール面圧保持機能の優れた油井管用ネジ継手
JP2005523404A (ja) * 2002-04-19 2005-08-04 ハイドリル・カンパニー 特に半径方向に塑性的に拡張可能な導管のためのねじ結合構造
JP2008215473A (ja) * 2007-03-02 2008-09-18 Sumitomo Metal Ind Ltd 鋼管用ねじ継手
WO2018135536A1 (fr) * 2017-01-18 2018-07-26 新日鐵住金株式会社 Raccord fileté
JP6916277B2 (ja) * 2017-05-15 2021-08-11 日本製鉄株式会社 鋼管用ねじ継手
WO2021013646A1 (fr) * 2019-07-19 2021-01-28 Vallourec Oil And Gas France Raccord fileté pour colonne de tubage d'un puits de pétrole
JP2022008003A (ja) * 2020-03-26 2022-01-13 株式会社NejiLaw 油井管連結構造及び油井管
WO2022090034A1 (fr) * 2020-10-28 2022-05-05 Vallourec Oil And Gas France Connexion filetée autobloquante partiellement en prise sans blocage

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