JP6020087B2 - Threaded joints for pipes - Google Patents
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- JP6020087B2 JP6020087B2 JP2012256078A JP2012256078A JP6020087B2 JP 6020087 B2 JP6020087 B2 JP 6020087B2 JP 2012256078 A JP2012256078 A JP 2012256078A JP 2012256078 A JP2012256078 A JP 2012256078A JP 6020087 B2 JP6020087 B2 JP 6020087B2
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- 238000007906 compression Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000007789 sealing Methods 0.000 description 6
- 239000003129 oil well Substances 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
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- 239000003345 natural gas Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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Description
本発明は、管用ねじ継手に関し、詳しくは一般に油井やガス井の探査や生産に使用されるチュービングおよびケーシングを包含する油井管、すなわちＯＣＴＧ(oil country tubular goods)、ライザー管、ならびにラインパイプなどの鋼管の接続に用いるのに好適な、シール性と耐圧縮性に優れた管用ねじ継手に関する。 The present invention relates to a threaded joint for pipes, and in particular, oil well pipes including tubing and casings generally used for exploration and production of oil wells and gas wells, that is, OCTG (oil country tubular goods), riser pipes, line pipes, etc. The present invention relates to a threaded joint for pipes suitable for use in connecting steel pipes and having excellent sealing properties and compression resistance.
ねじ継手は、油井管など産油産業設備に使用される鋼管の接続に広く使用されている。オイルやガスの探索や生産に使用される鋼管の接続には、従来ＡＰＩ（米国石油協会）規格に規定された標準的なねじ継手が典型的には使用されてきた。しかし、近年、原油や天然ガスの井戸は深井戸化が進み、垂直井から水平井や傾斜井等が増えていることから、掘削・生産環境は苛酷化している。また、海洋や極地など劣悪な環境での井戸の開発が増加していることなどから、耐圧縮性能、耐曲げ性能、外圧シール性能（耐外圧性能）など、ねじ継手への要求性能は多様化している。そのため、プレミアムジョイントと呼ばれる高性能の特殊ねじ継手を使用することが増加しており、その性能への要求もますます増加している。 Threaded joints are widely used to connect steel pipes used in oil industry equipment such as oil well pipes. Conventionally, a standard threaded joint specified in the API (American Petroleum Institute) standard has been typically used for connecting steel pipes used for oil and gas exploration and production. However, in recent years, the wells for crude oil and natural gas have been deepened, and the number of vertical wells, horizontal wells, inclined wells, etc. has increased, and the drilling and production environment has become severe. In addition, the demand for screw joints such as compression resistance, bending resistance, and external pressure seal performance (external pressure resistance) has diversified due to the increased development of wells in poor environments such as the ocean and polar regions. ing. For this reason, the use of high-performance special threaded joints called premium joints is increasing, and the demands on the performance are also increasing.
プレミアムジョイントは、通常、テーパねじ、シール部（詳しくはメタルタッチシール部）、ショルダ部（詳しくはトルクショルダ部）とをそれぞれ備える、管端部に形成した雄ねじ部材（以下、ピンと呼ぶ）と該ピン同士を連結する雌ねじ部材（以下、ボックスと呼ぶ）とを結合したカップリング形式の継手である。テーパねじは管継手を強固に固定するために重要であり、シール部はボックスとピンとがこの部分でメタル接触することでシール性を確保する役目を担い、ショルダ部は継手の締付け中にストッパの役目を担う当たり面を有する。 A premium joint usually has a male screw member (hereinafter referred to as a pin) formed on a pipe end portion, each having a taper screw, a seal portion (specifically, a metal touch seal portion), and a shoulder portion (specifically, a torque shoulder portion). It is a coupling type joint in which a female screw member (hereinafter referred to as a box) for connecting pins to each other is coupled. The taper screw is important for firmly fixing the pipe joint, and the seal part plays a role of securing the sealing performance by metal contact between the box and the pin at this part, and the shoulder part is a stopper of the joint during tightening. Has a contact surface to play a role.
図４は、油井管用プレミアムジョイントの従来例を示す模式的説明図であり、これらは、円管のねじ継手の縦断面図である。ねじ継手は、ピン３とこれに対応するボックス１とを備えており、ピン３は、その外面に雄ねじ部７と、ピン３の先端側に雄ねじ部７に隣接して設けられたねじの無い長さ部分であるノーズ部（ピンノーズとも云う）８を有する。ノーズ部８は、その外周面にシール部（詳しくは、メタルタッチシール部）１１を、その端面にはショルダ部（詳しくは、トルクショルダ部）１２を有する。相対するボックス１は、その内面に、それぞれピン３の雄ねじ部７、シール部１１、およびショルダ部１２と螺合するか、または接触することができる部分である、雌ねじ部５、シール部１３、および、ショルダ部１４を有している。 FIG. 4 is a schematic explanatory view showing a conventional example of a premium joint for an oil well pipe, and these are longitudinal sectional views of a threaded joint of a circular pipe. The threaded joint includes a pin 3 and a box 1 corresponding to the pin 3, and the pin 3 has a male screw portion 7 on the outer surface thereof, and has no screw provided adjacent to the male screw portion 7 on the tip end side of the pin 3. It has a nose portion (also called a pin nose) 8 that is a length portion. The nose portion 8 has a seal portion (specifically, a metal touch seal portion) 11 on its outer peripheral surface, and a shoulder portion (specifically, a torque shoulder portion) 12 on its end surface. The opposing box 1 has a female screw part 5, a seal part 13, and a part that can be screwed or brought into contact with the male screw part 7, the seal part 11, and the shoulder part 12 of the pin 3, respectively. And it has the shoulder part 14.
図４の従来例では、シール部１１がピン３の先端部にあり、適正な締付トルクを与えることにより所望のシール性能を実現できるのであるが、締付トルクは潤滑条件、表面性状等に影響されるので、これらに大きくは依存しない設計として、シール接触圧力の半径方向成分を相対的に強くした半径方向シール方式（ラジアルシール型とも云う）がある。
前記ラジアルシール型のプレミアムジョイントに関する従来技術として、耐圧縮性を高めるべく、ボックスのショルダ部の当たり面の断面積とピン素管の断面積の比を規定することが知られている（特許文献１参照）。
In the conventional example of FIG. 4, the seal portion 11 is at the tip of the pin 3 and a desired sealing performance can be realized by applying an appropriate tightening torque. However, the tightening torque depends on the lubrication conditions, surface properties, etc. As a design that does not greatly depend on these, there is a radial seal method (also referred to as a radial seal type) in which the radial component of the seal contact pressure is relatively strong.
As a prior art related to the radial seal type premium joint, it is known that the ratio of the cross-sectional area of the contact surface of the shoulder portion of the box and the cross-sectional area of the pin base tube is defined in order to improve the compression resistance (Patent Document). 1).
然し、本発明者らの検討によると、前記従来技術では、圧縮負荷時にピンとボックスのショルダ部同士の接触がピン先端の外径側で発生し、最悪の場合、ピンが塑性縮径変形してシール性が低下するため、高い圧縮負荷をかけることができないと云う課題があることが分った。 However, according to the study by the present inventors, in the prior art, the contact between the pin and the shoulder portion of the box occurs at the outer diameter side of the pin tip at the time of compressive load, and in the worst case, the pin is plastically deformed and deformed. It has been found that there is a problem that a high compression load cannot be applied because the sealing performance is lowered.
本発明者らは、前記課題を解決するために鋭意検討し、その結果、前記縮径変形を避けるには、前記ピンのショルダ部の当たり面（相手方と当接する平面乃至テーパ面）の外径（当たり面内でねじ継手軸からの半径が最大半径になる部位の前記最大半径×２の意。以下同じ）を、ボックスのショルダ部の当たり面の外径よりも小さくすることが有効である事、更には、ピンのショルダ部の当たり面より外側を適切に削り込むことにより耐圧縮性をより改善できる事を見出し、以下の要旨構成になる本発明を成した。
（１） 雄ねじ部と、該雄ねじ部より管端側に延在するノーズ部と、該ノーズ部の先端に設けられたショルダ部とを有するピンと、
前記雄ねじ部とねじ結合されてねじ部をなす雌ねじ部と、前記ピンのノーズ部外周面に相対するシール面と、前記ピンのショルダ部に当接するショルダ部とを有するボックスと、を有し、
前記ねじ結合により前記ピンとボックスとが結合されてピンの前記ノーズ部外周面とボックスの前記シール面とがメタル‐メタル接触しその接触部がシール部をなし、
前記ピンとボックス夫々のショルダ部はその少なくとも一部が相手方と当接する当たり面をなし、該当たり面はねじ継手軸に対し直交した平面、又はピン側では向求心法線、ボックス側では向遠心法線をもつテーパ面である管用ねじ継手であって、
前記ピン、ボックス双方の当たり面とねじ継手軸直交平面との交差角であるショルダ角が０度以上２０度以下であり、
前記ピンのショルダ部の当たり面の外径Ｄｓｐが、前記ボックスのショルダ部の当たり面の外径Ｄｓｂよりも小であり、
前記外径Ｄｓｐと、前記外径Ｄｓｂとの差であるピンとボックスの当たり面外径差２δ（＝Ｄｓｂ−Ｄｓｐ）が、０．０２”（＝０．５０８ｍｍ）以上０．０５”（＝１．２７０ｍｍ）以下であり、且つ、ピンの当たり面外径側にはピン内側に弦をもつ円弧状に削り込まれたピンショルダ部分が連接し、下記に定義されるピンショルダ部削り込み量βが０．００１”以上０．０１０”以下（即ち０．０２５４ｍｍ以上０．２５４ｍｍ以下）であることを特徴とする管用ねじ継手。
The present inventors have intensively studied to solve the above problems, and as a result, in order to avoid the diameter reduction deformation, the outer diameter of the contact surface of the shoulder portion of the pin (a flat surface or a tapered surface in contact with the counterpart). It is effective to make (the maximum radius x 2 of the portion where the radius from the threaded joint axis is the maximum radius within the contact surface, the same applies hereinafter) smaller than the outer diameter of the contact surface of the shoulder portion of the box. In addition, the present inventors have found that the compression resistance can be further improved by appropriately cutting the outer side of the contact surface of the shoulder portion of the pin, and the present invention having the following summary configuration has been made.
(1) a pin having a male screw portion, a nose portion extending from the male screw portion toward the tube end side, and a shoulder portion provided at the tip of the nose portion;
A female screw part that is screw-coupled with the male screw part to form a screw part, a seal surface that faces the outer peripheral surface of the nose part of the pin, and a box that has a shoulder part that contacts the shoulder part of the pin,
The screw and the pin are connected to the box, and the outer peripheral surface of the pin and the seal surface of the box are in metal-metal contact, and the contact portion forms a seal portion.
The shoulder portion of each of the pin and the box has a contact surface at least a part of which is in contact with the counterpart, the corresponding surface is a plane orthogonal to the screw joint axis, or the centripetal normal on the pin side, and the centrifugal method on the box side A threaded joint for pipes, which is a tapered surface with a line,
The shoulder angle which is the intersection angle between the contact surfaces of both the pin and the box and the threaded joint axis orthogonal plane is 0 degree or more and 20 degrees or less,
The outer diameter Dsp of the contact surface of the shoulder portion of the pin, Ri Oh small than the outer diameter Dsb abutment surface of the shoulder portion of the box,
The contact surface outer diameter difference 2δ (= Dsb−Dsp) between the pin and the box, which is the difference between the outer diameter Dsp and the outer diameter Dsb, is 0.02 ″ (= 0.508 mm) or more and 0.05 ″ (= 1 270 mm) or less, and a pin shoulder portion cut into an arc shape having a chord inside the pin is connected to the pin contact surface outer diameter side, and the pin shoulder portion cutting amount β defined below is 0 pipe thread joint it is a .001 "or more 0.010" or less (ie 0.0254mm least 0.254mm or less).
記
ピンショルダ部削り込み量βとは、ピンのショルダ部の当たり面を外径側に展延してなるピン当たり面展延面の面内の外径が前記外径Ｄｓｂに等しい点から、前記円弧状に削り込まれたピンショルダ部分までの、ねじ継手軸方向のピン先端側から雄ねじ部側への向きを正とする距離を意味する。
The pin shoulder portion cutting amount β is the point that the outer diameter in the surface of the pin contact surface extending surface obtained by extending the contact surface of the shoulder portion of the pin to the outer diameter side is equal to the outer diameter Dsb. The distance from the pin tip side in the axial direction of the threaded joint to the male threaded portion side to the pin shoulder portion cut into an arc shape means a positive distance.
本発明によれば、上記構成を採用した事で、圧縮負荷時のピンの塑性縮径変形を抑制でき、耐圧縮性に優れる管用ねじ継手が得られる。 According to the present invention, by adopting the above-described configuration, it is possible to obtain a threaded joint for pipes that can suppress plastic diameter reduction deformation of a pin during a compression load and is excellent in compression resistance.
図１は、本発明（１）の一実施形態を示すねじ継手軸方向断面図である。図１は、ピン３とボックス１のねじ結合完了直前状態に対応する、ピン図面とボックス図面の重ね合わせ図であり、ピンノーズ８の非ショルダ部とボックス１内面のピンノーズ対向部とが、結合完了時にはシール部になる、干渉部２０を形成している。尚、結合完了時に対応させた場合の前記重ね合わせ図における干渉部２０でみてボックス/ピン間の半径差が最大になる部位の前記半径差をシール干渉量と云う。 FIG. 1 is a sectional view in the axial direction of a threaded joint showing an embodiment of the present invention (1). FIG. 1 is a superimposed view of the pin drawing and the box drawing corresponding to the state immediately before the screw connection between the pin 3 and the box 1 is completed, and the non-shoulder portion of the pin nose 8 and the pin nose facing portion on the inner surface of the box 1 are completed. Interference part 20 is formed which sometimes becomes a seal part. It should be noted that the radius difference at the portion where the radius difference between the box / pin is the maximum when viewed from the interference portion 20 in the superimposed view when the coupling is completed is referred to as a seal interference amount.
ピン３のショルダ部１２とボックス１のショルダ部１４とは、夫々その少なくとも一部が相手方と当接する当たり面２２，２４をなし、当たり面２２，２４はねじ継手軸に対し直交した平面（ねじ継手軸直交平面３０）、又はピン側では向求心法線２２Ｈ、ボックス側では向遠心法線２４Ｈをもつテーパ面である。これにより、ボックス１の当たり面２４からピン３の当たり面２２への接触反力は、向求心成分が無くてピンノーズ８の縮径変形に寄与しないか、又は向遠心成分が有ってピンノーズ８の縮径変形に抵抗する。このとき、当たり面２２，２４とねじ継手軸直交平面３０との交差角であるショルダ角θは０度以上である。但し、ショルダ角θが２０度超であると、ボックス１の当たり面２４からピン３の当たり面２２への接触反力の向遠心成分が過大となってシール部にダメージが発生する。よって、ショルダ角θは０度以上２０度以下とする。 The shoulder portion 12 of the pin 3 and the shoulder portion 14 of the box 1 have contact surfaces 22 and 24, respectively, at least a part of which contacts the counterpart, and the contact surfaces 22 and 24 are flat surfaces (screw The joint axis orthogonal plane 30) or a taper surface having a centripetal normal line 22H on the pin side and a centrifugal normal line 24H on the box side. As a result, the contact reaction force from the contact surface 24 of the box 1 to the contact surface 22 of the pin 3 has no centripetal component and does not contribute to the reduced diameter deformation of the pin nose 8, or has a procentrifugal component and the pin nose 8. Resistes to reduced diameter deformation. At this time, a shoulder angle θ that is an intersection angle between the contact surfaces 22 and 24 and the threaded joint axis orthogonal plane 30 is 0 degree or more. However, if the shoulder angle θ is more than 20 degrees, the anti-centrifugal component of the contact reaction force from the contact surface 24 of the box 1 to the contact surface 22 of the pin 3 becomes excessive, and the seal portion is damaged. Therefore, the shoulder angle θ is set to 0 degree or more and 20 degrees or less.
ピン３のショルダ部１２の当たり面２２の外径Ｄｓｐは、ボックス１のショルダ部１４の当たり面２４の外径Ｄｓｂよりも小である。これにより、ピン３先端部へのボックス１側からの縮径方向の押し力の発生が防止でき、該押し力に起因するシール部の接触弱化を抑制できる。
図２は、本発明の好適な一実施形態である本発明（２）における、ピンノーズ先端部の削り込みを示すねじ継手軸方向断面図であり、この図２は図１と同様、ピン３とボックス１のねじ結合完了直前状態に対応する、ピン図面とボックス図面の重ね合わせ図であり、ピンノーズ８の非ショルダ部とボックス１内面のピンノーズ対向部とが、結合完了時にはシール部になる、干渉部２０を形成している。図２において、δは、ピン３とボックス１の当たり面外径差２δ（≡Ｄｓｂ−Ｄｓｐ）の１/２、即ちδ≡２δ/２であり、２δは、２δ：０．０２”（＝２δ１）以上０．０５”（＝２δ２）以下である。又、ピン３の当たり面２２外径側にはピン内側に弦をもつ円弧状に削り込まれたピンショルダ部分２５が滑らかに連接しており、ピン３のショルダ部１２の当たり面２２を外径側に展延してなるピン当たり面展延面２２Ａの面内の外径が外径Ｄｓｂに等しい点から、前記円弧状に削り込まれたピンショルダ部分２５までの、ねじ継手軸方向のピン先端側から雄ねじ部側への向きを正とする距離で定義されるピンショルダ部削り込み量βが０．００１”（＝β１）以上０．０１０”（＝β２）以下である。尚、図示の様に、外径Ｄｓｂ、外径Ｄｓｐの各点におけるピン/ボックス間のねじ継手軸方向間隔を夫々Ｌ２，Ｌ１と記すと、β＝Ｌ２−L1、である。
The outer diameter Dsp of the contact surface 22 of the shoulder portion 12 of the pin 3 is smaller than the outer diameter Dsb of the contact surface 24 of the shoulder portion 14 of the box 1. Thereby, generation | occurrence | production of the pressing force of the diameter reduction direction from the box 1 side to the pin 3 tip part can be prevented, and the contact weakening of the seal part resulting from this pressing force can be suppressed.
FIG. 2 is a cross-sectional view in the axial direction of the threaded joint showing the cutting of the tip of the pin nose in the present invention (2) which is a preferred embodiment of the present invention. This FIG. 2 is similar to FIG. FIG. 4 is a superimposed view of a pin drawing and a box drawing corresponding to a state immediately before the screw connection of the box 1 is completed. Part 20 is formed. In FIG. 2, δ is 1/2 of the contact surface outer diameter difference 2δ (≡Dsb−Dsp) between the pin 3 and the box 1, that is, δ≡2δ / 2, and 2δ is 2δ: 0.02 ″ (= 2δ 1 ) or more and 0.05 ″ (= 2δ 2 ) or less. Further, a pin shoulder portion 25 cut into an arc shape with a string inside the pin is smoothly connected to the outer diameter side of the contact surface 22 of the pin 3, and the contact surface 22 of the shoulder portion 12 of the pin 3 is connected to the outer diameter. Pin tip in the axial direction of the threaded joint from the point where the outer diameter in the surface of the pin contact surface extended surface 22A extended to the side is equal to the outer diameter Dsb to the pin shoulder portion 25 cut into the arc shape The pin shoulder portion cutting amount β defined by a distance with the direction from the side to the male screw portion as positive is 0.001 ″ (= β 1 ) or more and 0.010 ″ (= β 2 ) or less. As shown in the figure, when the screw joint axial distance between the pin / box at each point of the outer diameter Dsb and the outer diameter Dsp is denoted as L2 and L1, respectively, β = L2−L1.
本発明（２）によれば、ピン先端の接触反力発生をより強く防止する効果（便宜上、効果Ａと云う）を奏する。又、大きな圧縮力が作用した場合、従来技術の範疇では、ボックス１のショルダ部１４が塑性変形してピン先端部の減り込み（めりこみ）が生じがちとなるが、斯かる場合でも、本発明（２）によれば、ボックス１のショルダ部１４の塑性変形を抑制し、ピン先端の減り込みを生じ難くする効果（便宜上、効果Ｂと云う）を奏する。２δ＜２δ１又はβ＜β１であると、前記効果Ａに乏しく、一方、２δ＞２δ２又はβ＞β２であると、前記効果Ｂに乏しいので、２δ１≦２δ≦２δ２、且つ、β１≦β≦β２とする事が好ましい。 According to the present invention (2), the effect of preventing the generation of the contact reaction force at the tip of the pin more strongly (referred to as effect A for convenience) is achieved. Further, when a large compressive force is applied, the shoulder portion 14 of the box 1 tends to be plastically deformed to cause the pin tip portion to be reduced (recessed) in the category of the prior art. According to (2), there is an effect (referred to as an effect B for convenience) that suppresses plastic deformation of the shoulder portion 14 of the box 1 and makes it difficult for the pin tip to decrease. If 2δ <2δ 1 or β <β 1 , the effect A is poor, while if 2δ> 2δ 2 or β> β 2 , the effect B is poor, so 2δ 1 ≦ 2δ ≦ 2δ 2 , and , Β 1 ≦ β ≦ β 2 is preferable.
図３は、Ｄｓｐ＝Ｄｓｂとした従来例（図３（ａ））、Ｄｓｂ＞Ｄｓｐかつβ＜０．００１”とした本発明（１）相当例（図３（ｂ））、Ｄｓｂ＞Ｄｓｐかつβ＝０．００１”とした本発明（２）相当例（図３（ｃ））の各々について、ＩＳＯ試験に規定された複合荷重負荷後の相当塑性ひずみ分布のＦＥＡ計算結果の例を示す等ひずみ区域図である。図３において、２１はシール部であり、前掲図と同一部または相当部には同じ符号を付し、説明を省略する。図３より、本発明（１）相当例ではピン先端の塑性変形が従来例よりも低減している事、及び、本発明（２）相当例ではピン先端の塑性変形が本発明（１）相当例よりも低減している事が分る。 FIG. 3 shows a conventional example in which Dsp = Dsb (FIG. 3A), an example corresponding to the present invention (1) in which Dsb> Dsp and β <0.001 ″ (FIG. 3B), Dsb> Dsp and An example of the FEA calculation result of the equivalent plastic strain distribution after complex load loading specified in the ISO test is shown for each of the examples corresponding to (2) of the present invention in which β = 0.001 ″ (FIG. 3C), etc. It is a strain area figure. In FIG. 3, reference numeral 21 denotes a seal portion. From FIG. 3, the plastic deformation at the pin tip is reduced in the example corresponding to the present invention (1) compared to the conventional example, and the plastic deformation at the pin tip is equivalent to the present invention (1) in the corresponding example of the present invention (2). You can see that it is lower than the example.
外径９-５/８”×肉厚０．５４５”の鋼管端部を加工してなるピンと、これに対応するボックスとからなる管用ねじ継手について、有限要素解析（ＦＥＡ）を実施してＭＵ（Ｍａｋｅ Ｕｐ；締付）時の接触面積圧（面圧を管軸方向の接触長に渡って積分した指標）を同一とした設計で、サンプルを製作し、ＩＳＯ１３６７９のシリーズＡテストを実施した。この実施に当たっては表１に実験条件を示す各水準で実験した。尚、実験では、ＭＵ完了時の接触面積圧が６０００ｐｓｉ-ｉｎｃｈとなる様にシール干渉量とＭＵトルクを調整した。 Finite element analysis (FEA) is performed on a threaded joint for a pipe consisting of a pin formed by machining a steel pipe end with an outside diameter of 9-5 / 8 "x wall thickness of 0.545" and a box corresponding to the pin. Samples were manufactured with the same contact area pressure (index obtained by integrating the surface pressure over the contact length in the tube axis direction) at the time of (Make Up; tightening), and a series A test of ISO 13679 was performed. In carrying out this experiment, the experiment was conducted at various levels shown in Table 1. In the experiment, the seal interference amount and the MU torque were adjusted so that the contact area pressure upon completion of MU was 6000 psi-inch.
実験結果を表１に示す。表１より、比較例と比べて、本発明例では、より優れたシール性が発現し、又、本発明例においてピンのショルダ部の当たり面より外側を適切に削り込んだ例では、より一層優れたシール性が発現した事が明らかである。 The experimental results are shown in Table 1. From Table 1, compared with the comparative example, in the example of the present invention, a better sealing property is exhibited, and in the example of the present invention, the outer side of the contact surface of the shoulder portion of the pin is appropriately cut off. It is clear that excellent sealing performance has been developed.
１ ボックス
３ ピン
５ 雌ねじ部
７ 雄ねじ部
８ ノーズ部（ピンノーズ）
１１，１３ シール部（メタルタッチシール部）
１２，１４ ショルダ部（トルクショルダ部；１２はピン側、１４はボックス側）
２０ シール部になる干渉部
２１ シール部
２２，２４ 当たり面（２２はピン側、２４はボックス側）
２２Ａ ピン当たり面展延面
２２Ｈ 向求心法線
２４Ｈ 向遠心法線
２５ 円弧状に削り込まれたピンショルダ部分
３０ ねじ継手軸直交平面
1 Box 3 Pin 5 Female thread 7 Male thread 8 Nose (pin nose)
11, 13 Seal part (metal touch seal part)
12, 14 Shoulder (torque shoulder; 12 is pin side, 14 is box side)
20 Interference part 21 which becomes seal part Seal part 22, 24 Contact surface (22 is pin side, 24 is box side)
22A Surface expansion surface per pin 22H Centripetal normal 24H Centrifugal normal 25 Pin shoulder portion 30 cut into an arc shape Thread joint axis orthogonal plane
Claims (1)
前記雄ねじ部とねじ結合されてねじ部をなす雌ねじ部と、前記ピンのノーズ部外周面に相対するシール面と、前記ピンのショルダ部に当接するショルダ部とを有するボックスと、を有し、
前記ねじ結合により前記ピンとボックスとが結合されてピンの前記ノーズ部外周面とボックスの前記シール面とがメタル‐メタル接触しその接触部がシール部をなし、
前記ピンとボックス夫々のショルダ部はその少なくとも一部が相手方と当接する当たり面をなし、該当たり面はねじ継手軸に対し直交した平面、又はピン側では向求心法線、ボックス側では向遠心法線をもつテーパ面である管用ねじ継手であって、
前記ピン、ボックス双方の当たり面とねじ継手軸直交平面との交差角であるショルダ角が０度以上２０度以下であり、
前記ピンのショルダ部の当たり面の外径Ｄｓｐが、前記ボックスのショルダ部の当たり面の外径Ｄｓｂよりも小であり、
前記外径Ｄｓｐと、前記外径Ｄｓｂとの差であるピンとボックスの当たり面外径差２δ（＝Ｄｓｂ−Ｄｓｐ）が、０．０２”（＝０．５０８ｍｍ）以上０．０５”（＝１．２７０ｍｍ）以下であり、且つ、ピンの当たり面外径側にはピン内側に弦をもつ円弧状に削り込まれたピンショルダ部分が連接し、下記に定義されるピンショルダ部削り込み量βが０．００１”以上０．０１０”以下（即ち０．０２５４ｍｍ以上０．２５４ｍｍ以下）であることを特徴とする管用ねじ継手。
記
ピンショルダ部削り込み量βとは、ピンのショルダ部の当たり面を外径側に展延してなるピン当たり面展延面の面内の外径が前記外径Ｄｓｂに等しい点から、前記円弧状に削り込まれたピンショルダ部分までの、ねじ継手軸方向のピン先端側から雄ねじ部側への向きを正とする距離を意味する。 A pin having a male screw part, a nose part extending from the male screw part to the tube end side, and a shoulder part provided at the tip of the nose part;
A female screw part that is screw-coupled with the male screw part to form a screw part, a seal surface that faces the outer peripheral surface of the nose part of the pin, and a box that has a shoulder part that contacts the shoulder part of the pin,
The screw and the pin are connected to the box, and the outer peripheral surface of the pin and the seal surface of the box are in metal-metal contact, and the contact portion forms a seal portion.
The shoulder portion of each of the pin and the box has a contact surface at least a part of which is in contact with the counterpart, the corresponding surface is a plane orthogonal to the screw joint axis, or the centripetal normal on the pin side, and the centrifugal method on the box side A threaded joint for pipes, which is a tapered surface with a line,
The shoulder angle which is the intersection angle between the contact surfaces of both the pin and the box and the threaded joint axis orthogonal plane is 0 degree or more and 20 degrees or less,
The outer diameter Dsp of the contact surface of the shoulder portion of the pin is smaller than the outer diameter Dsb of the contact surface of the shoulder portion of the box,
The contact surface outer diameter difference 2δ (= Dsb−Dsp) between the pin and the box, which is the difference between the outer diameter Dsp and the outer diameter Dsb, is 0.02 ″ (= 0.508 mm) or more and 0.05 ″ (= 1 270 mm) or less, and a pin shoulder portion cut into an arc shape having a chord inside the pin is connected to the pin contact surface outer diameter side, and the pin shoulder portion cutting amount β defined below is 0 pipe thread joint it is a .001 "or more 0.010" or less (ie 0.0254mm least 0.254mm or less).
The pin shoulder portion cutting amount β is the point that the outer diameter in the surface of the pin contact surface extending surface obtained by extending the contact surface of the shoulder portion of the pin to the outer diameter side is equal to the outer diameter Dsb. The distance from the pin tip side in the axial direction of the threaded joint to the male threaded portion side to the pin shoulder portion cut into an arc shape means a positive distance.
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