WO2020039875A1 - 鋼管用ねじ継手 - Google Patents
鋼管用ねじ継手 Download PDFInfo
- Publication number
- WO2020039875A1 WO2020039875A1 PCT/JP2019/030172 JP2019030172W WO2020039875A1 WO 2020039875 A1 WO2020039875 A1 WO 2020039875A1 JP 2019030172 W JP2019030172 W JP 2019030172W WO 2020039875 A1 WO2020039875 A1 WO 2020039875A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pin
- box
- shoulder surface
- shoulder
- threaded joint
- Prior art date
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 46
- 239000010959 steel Substances 0.000 title claims abstract description 46
- 238000007789 sealing Methods 0.000 claims description 52
- 230000002093 peripheral effect Effects 0.000 description 46
- 238000012360 testing method Methods 0.000 description 35
- 230000008878 coupling Effects 0.000 description 10
- 238000010168 coupling process Methods 0.000 description 10
- 238000005859 coupling reaction Methods 0.000 description 10
- 238000000034 method Methods 0.000 description 10
- 239000003129 oil well Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002343 natural gas well Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- F16L15/001—Screw-threaded joints; Forms of screw-threads for such joints with conical threads
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
- E21B17/042—Threaded
-
- 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
- F16L15/001—Screw-threaded joints; Forms of screw-threads for such joints with conical threads
- F16L15/004—Screw-threaded joints; Forms of screw-threads for such joints with conical threads with axial sealings having at least one plastically deformable sealing surface
Definitions
- the present invention relates to a threaded joint used for connecting steel pipes.
- oil wells In oil wells, natural gas wells, and the like (hereinafter collectively referred to as “oil wells”), steel pipes called OCTG (Oil Country Tubular Goods) are used to extract underground resources.
- OCTG Oil Country Tubular Goods
- the steel pipes are connected sequentially.
- a threaded joint is used for connecting steel pipes.
- Types of threaded joints for steel pipes are broadly classified into coupling types and integral types.
- one of the pair of pipes to be connected is a steel pipe, and the other is a coupling.
- a male screw portion is formed on the outer periphery of both ends of the steel pipe, and a female screw portion is formed on the inner periphery of both ends of the coupling. Then, the steel pipe and the coupling are connected.
- the pair of pipes to be connected are both steel pipes, and no separate coupling is used.
- a male screw portion is formed on the outer circumference of one end of the steel pipe, and a female screw portion is formed on the inner circumference of the other end. And one steel pipe and the other steel pipe are connected.
- the joint portion at the pipe end where the male screw portion is formed is called a pin because it includes an element inserted into the female screw portion.
- the joint portion at the pipe end where the female screw portion is formed is called a box because it includes an element for receiving the male screw portion. Since these pins and boxes are the ends of the tubing, they are both tubular.
- FIG. 1 is a longitudinal sectional view showing a conventional typical threaded joint for steel pipes.
- the threaded joint shown in FIG. 1 is a coupling type threaded joint, and is composed of a pin 10 and a box 20 (for example, see Japanese Patent Application Laid-Open No. 10-096489 (Patent Document 1)).
- the pin 10 includes an annular shoulder surface 12, an annular sealing surface 13, and a male screw portion 14 in order from the tip of the pin 10 toward the tube main body 11 of the pin 10.
- the sealing surface 13 is adjacent to the shoulder surface 12.
- the box 20 includes an annular shoulder surface 22, an annular sealing surface 23, and a female screw portion 24 in order from the tube main body 21 of the box 20 toward the tip of the box 20.
- sealing surface 23 is adjacent to shoulder surface 22.
- the shoulder surface 12 of the pin 10 comes into contact with the shoulder surface 22 of the box 20 by screwing the pin 10 into the box 20. Subsequently, when the pin 10 is rotated by a predetermined amount, a fastening axial force is generated in the male screw portion 14 and the female screw portion 24 that mesh with each other, and the fastening is completed. In a state where the fastening is completed (hereinafter, also referred to as a “fastened state”), the sealing surface 13 of the pin 10 comes into contact with the sealing surface 23 of the box 20 while interfering with each other, and a sealing portion is formed by metal contact. With this seal portion, the sealing performance of the threaded joint is ensured.
- the compressive load is received by the contact surface between the shoulder surface 12 of the pin 10 and the shoulder surface 22 of the box 20 (hereinafter, also referred to as “shoulder contact surface”).
- shoulder contact surface the entire area of the shoulder surface 12 of the pin 10 contacts the entire area of the shoulder surface 22 of the box 20 in order to ensure the maximum area of the shoulder contact surface. That is, the diameter Dpi of the inner peripheral edge of the shoulder surface 12 of the pin 10 is substantially the same as the diameter Dbi of the inner peripheral edge of the shoulder surface 22 of the box 20.
- One object of the present invention is to provide a threaded joint for steel pipes that can sufficiently secure sealing performance against external pressure even when a thick steel pipe is used.
- the threaded joint for a steel pipe includes a tubular pin and a tubular box.
- the pin includes an annular shoulder surface, an annular seal surface adjacent to the shoulder surface of the pin, and a male thread portion in order from the tip of the pin toward the tube body of the pin.
- the box includes, in order from the tube body of the box toward the tip of the box, an annular shoulder surface, an annular sealing surface adjacent to the shoulder surface of the box, and a female screw portion.
- the shoulder surface of each of the pin and the box inclines from the plane perpendicular to the tube axis in the direction in which the pins are screwed.
- the diameter of the inner periphery of the shoulder surface of the pin is smaller than the diameter of the inner periphery of the shoulder surface of the box.
- FIG. 1 is a longitudinal sectional view showing a conventional typical threaded joint for steel pipes.
- FIG. 2 is a longitudinal sectional view showing the threaded joint for steel pipe of the present embodiment.
- FIG. 3 is a longitudinal sectional view in which the vicinity of the tip of the pin of the threaded joint shown in FIG. 2 is enlarged.
- FIG. 4 is an enlarged longitudinal sectional view of the vicinity of the tip of the pin of the threaded joint shown in FIG.
- the first method was derived from the following inferences. If the thickness of the pin seal portion 15 is large, the radial rigidity of the pin seal portion 15 is increased. As a result, the elastic recovery force of the pin seal portion 15 is improved, and the contact force between the sealing surface 13 of the pin 10 and the sealing surface 23 of the box 20 in the fastened state (hereinafter, also referred to as “seal contact force”) is increased. The sealing performance against internal and external pressures is improved. Further, the diameter reduction deformation of the pin seal portion 15 when an external pressure is applied to the pin 10 is suppressed. Therefore, even when an external pressure is applied, a decrease in the seal contact force can be reduced. Therefore, it may be said that a decrease in sealing performance against external pressure can be suppressed.
- the area of the shoulder surface 12 of the pin 10 is large due to the thickening of the pin seal portion 15.
- the entire shoulder surface 12 of the pin 10 contacts the entire shoulder surface 22 of the box 20. Therefore, the area of the shoulder surface 22 of the box 20 is large. That is, the area of the shoulder contact surface is large.
- shoulder contact force the contact force between the shoulder surface 12 of the pin 10 and the shoulder surface 22 of the box 20 (hereinafter, also referred to as “shoulder contact force”) is uneven within the shoulder contact surface. become.
- the seal portion adjacent to the shoulder contact surface is greatly affected. Therefore, in actuality, the contact of the seal portion becomes unstable, and the sealing performance decreases.
- the rigidity of the pin seal 15 in the radial direction is low due to the thinning of the pin seal 15.
- the pin seal portion 15 is liable to be reduced in diameter. Therefore, the sealing performance against external pressure actually decreases.
- neither the first nor the second technique can ensure the sealing performance against external pressure.
- the present inventors focused on the pin seal portion and the shoulder contact surface in view of the problems of the first and second methods. Specifically, the thickness of the pin seal portion is increased, and the area of the shoulder contact surface is reduced. Thereby, the shoulder contact force becomes uniform in the shoulder contact surface while the radial rigidity of the pin seal portion is increased. Therefore, it is possible to stabilize the contact of the seal portion. As a result, sealing performance against external pressure can be ensured.
- the threaded joint for a steel pipe includes a tubular pin and a tubular box.
- the pin includes an annular shoulder surface, an annular seal surface adjacent to the shoulder surface of the pin, and a male thread portion in order from the tip of the pin toward the tube body of the pin.
- the box includes, in order from the tube body of the box toward the tip of the box, an annular shoulder surface, an annular sealing surface adjacent to the shoulder surface of the box, and a female screw portion.
- the shoulder surface of each of the pin and the box inclines from the plane perpendicular to the tube axis in the direction in which the pins are screwed.
- the diameter of the inner periphery of the shoulder surface of the pin is smaller than the diameter of the inner periphery of the shoulder surface of the box.
- the threaded joint of the present embodiment is used for connecting a thick steel pipe used for a casing or tubing.
- the wall thickness of the thick steel pipe exceeds 1 inch (25.4 mm).
- the area of the shoulder surface of the pin is large, and the area of the shoulder surface of the box is small. This is because the diameter of the inner peripheral edge of the shoulder surface of the pin is smaller than the diameter of the inner peripheral edge of the shoulder surface of the box. This increases the thickness of the pin seal portion, thereby increasing the radial rigidity of the pin seal portion. In addition, since the area of the shoulder contact surface is small, the shoulder contact force becomes uniform within the shoulder contact surface.
- the shoulder surface of the pin comes into pressure contact with the shoulder surface of the box in a hook-like form.
- the shoulder surfaces of the pin and the box are inclined from the plane perpendicular to the tube axis in the direction in which the pins are screwed.
- the pin seal portion always receives a reaction force in the direction in which the diameter is increased. Therefore, when an external pressure is applied to the pin, the pin seal portion is unlikely to be reduced in diameter.
- the angle of inclination of the shoulder surface of each of the pin and the box with respect to a plane perpendicular to the pipe axis is 5 ° to 20 °. If the inclination angle of the shoulder surface is 5 ° or more, the shoulder surface of the pin effectively presses and contacts the shoulder surface of the box in a hook-like form in the fastened state. Preferably, the inclination angle of the shoulder surface is 10 ° or more. On the other hand, if the inclination angle of the shoulder surface is 20 ° or less, the deformation of the shoulder portion of the box is small even when a compressive load is repeatedly applied. Therefore, the pressing contact between the shoulder surfaces in the hook-like form is effectively maintained.
- the thickness tp of the annular pin shoulder region that appears when the shoulder surface of the pin is projected on a plane perpendicular to the tube axis is preferably 60% or more of the wall thickness t of the tube body of the pin. . If the thickness tp of the pin shoulder region is 60% or more of the thickness t of the tube body of the pin, the thickness of the pin seal portion is effectively increased.
- the upper limit of the thickness tp of the pin shoulder region is not particularly limited. However, if the thickness tp of the pin shoulder region is too large, it becomes difficult to secure the length of the male screw portion. Therefore, the thickness tp of the pin shoulder region is preferably 80% or less of the wall thickness t of the tube body of the pin.
- the thickness tb of the annular box shoulder region that appears when the shoulder surface of the box is projected onto a plane perpendicular to the tube axis is 20% or more and 55% or less of the wall thickness t of the tube body of the pin.
- the box shoulder region corresponds to an annular shoulder contact surface region that appears when the shoulder contact surface is projected onto a plane perpendicular to the tube axis.
- the thickness tb of the box shoulder region is not less than 20% of the wall thickness t of the pin tube body, when an excessive compressive load is applied to the threaded joint, the shoulder surface and adjacent to the shoulder surface. Plastic deformation of the seal surface can be suppressed, and the contact state of the seal surface can be stabilized. Therefore, a sealing contact force can be secured. More preferably, the thickness tb of the box shoulder region is 30% or more of the wall thickness t of the tube body of the pin. On the other hand, if the thickness tb of the box shoulder region is 55% or less of the wall thickness t of the tube body of the pin, the area of the shoulder contact surface is effectively reduced. More preferably, the thickness tb of the box shoulder region is 45% or less of the thickness t of the tube body of the pin.
- FIG. 2 is a longitudinal sectional view showing the threaded joint for steel pipe of the present embodiment.
- 3 and 4 are enlarged longitudinal sectional views of the vicinity of the tip of the pin of the threaded joint shown in FIG.
- FIG. 3 shows a fastening state.
- FIG. 4 shows a state in which the pin 10 is separated from the box 20 for convenience of explanation. 2 to 4 indicate the direction in which the pin 10 is screwed into the box 20.
- the longitudinal section means a section including the pipe axis CL (see FIG. 2) of the threaded joint.
- the threaded joint of the present embodiment is a coupling type threaded joint and includes a pin 10 and a box 20.
- the pin 10 is a thick steel pipe.
- the pin 10 includes an annular shoulder surface 12, an annular sealing surface 13, and a male screw portion 14 in order from the tip of the pin 10 toward the tube main body 11 of the pin 10.
- the shoulder surface 12 of the pin 10 is also referred to as a “pin shoulder surface”.
- the sealing surface 13 of the pin 10 is also called a “pin sealing surface”.
- the pin shoulder surface 12 is an annular surface that forms the tip end surface of the pin 10, and is inclined in the screwing direction of the pin 10 from a plane perpendicular to the tube axis CL.
- the outer peripheral edge 12b of the pin shoulder surface 12 protrudes in the screwing direction of the pin 10 than the inner peripheral edge 12a of the pin shoulder surface 12 (the edge closer to the pipe axis CL).
- the pin seal surface 13 is adjacent to the pin shoulder surface 12. That is, the pin seal surface 13 is connected to the outer peripheral edge 12b of the pin shoulder surface 12.
- the pin seal surface 13 is a tapered annular surface.
- the pin seal surface 13 may have a shape combining a tapered annular surface and a surface corresponding to the peripheral surface of a rotating body obtained by rotating a curve such as an arc around the tube axis CL.
- the diameter of the pin seal surface 13 is smaller toward the tip end of the pin 10 (the pin shoulder surface 12 side).
- the box 20 includes an annular shoulder surface 22, an annular sealing surface 23, and a female screw portion 24 in order from the pipe main body 21 of the box 20 toward the tip of the box 20.
- the shoulder surface 22 of the box 20 is also referred to as a “box shoulder surface”.
- the sealing surface 23 of the box 20 is also called a “box sealing surface”.
- the box shoulder surface 22 is an annular surface corresponding to the pin shoulder surface 12, and is inclined in the screwing direction of the pin 10 from a plane perpendicular to the pipe axis CL.
- the inner peripheral edge 22a of the box shoulder surface 22 (the edge closer to the tube axis CL) is more advanced in the screwing direction of the pin 10 than the outer peripheral edge 22b of the box shoulder surface 22 (the edge farther from the tube axis CL).
- Box seal surface 23 is adjacent to box shoulder surface 22. That is, the box seal surface 23 is connected to the outer peripheral edge 22b of the box shoulder surface 22.
- the box seal surface 23 is a tapered annular surface corresponding to the pin seal surface 13.
- the box seal surface 23 may have a shape in which a tapered annular surface and a surface corresponding to a peripheral surface of a rotating body obtained by rotating a curve such as an arc around the tube axis CL may be combined. .
- the male thread 14 of the pin 10 corresponds to the female thread 24 of the box 20.
- the male screw portion 14 and the female screw portion 24 include a screw top surface, a screw bottom surface, an insertion flank surface, and a load flank surface, respectively.
- the diameter Dpi of the inner peripheral edge 12a of the pin shoulder surface 12 is smaller than the diameter Dbi of the inner peripheral edge 22a of the box shoulder surface 22. That is, the area of the pin shoulder surface 12 is large, and the area of the box shoulder surface 22 is small. Therefore, the area of shoulder contact surface 30 is small.
- the diameter Dpi of the inner peripheral edge 12 a of the pin shoulder surface 12 is the same as the inner diameter of the tube body 11 of the pin 10. That is, the inner diameter of the pin 10 is constant.
- the inclination angles ⁇ p and ⁇ b of the pin shoulder surface 12 and the box shoulder surface 22 with respect to a plane perpendicular to the tube axis CL are 5 ° to 20 °.
- the thickness tp of the annular pin shoulder region that appears when the pin shoulder surface 12 is projected on a plane perpendicular to the tube axis CL is 60% or more of the wall thickness t of the tube body 11 of the pin 10.
- the thickness tb of the annular box shoulder region that appears when the box shoulder surface 22 is projected onto a plane perpendicular to the tube axis CL is 20% or more and 55% or less of the wall thickness t of the tube body 11 of the pin 10.
- the male thread 14 engages with the female thread 24 by screwing the pin 10 into the box 20.
- a portion of the pin shoulder surface 12 contacts the entire area of the box shoulder surface 22. That is, the pin shoulder surface 12 contacts the box shoulder surface 22 in the range of the shoulder contact surface 30.
- a part of the pin shoulder surface 12 comes into pressure contact with the entire area of the box shoulder surface 22 in a hook-like form.
- a tightening axial force is generated in the male screw portion 14 and the female screw portion 24 that mesh with each other, and the fastening is completed.
- the pin seal surface 13 comes into contact with the box seal surface 23 while interfering with each other, and a seal portion is formed by metal contact. With this seal portion, the sealing performance of the threaded joint is ensured.
- the area of the pin shoulder surface 12 is large and the area of the box shoulder surface 22 is small. This increases the thickness of the pin seal portion 15, thereby increasing the radial rigidity of the pin seal portion 15. Further, since the area of the shoulder contact surface 30 is small, the shoulder contact force becomes uniform within the shoulder contact surface 30.
- a part of the pin shoulder surface 12 comes into pressure contact with the entire area of the box shoulder surface 22 in a hook-like form in the fastened state.
- the pin seal portion 15 always receives a reaction force in the direction of increasing the diameter. Therefore, when an external pressure is applied to the pin 10, the pin seal portion 15 is unlikely to be deformed in a reduced diameter.
- the material was an isotropically hardened elasto-plastic body.
- the elastic modulus was 210 GPa, and the yield strength as 0.2% proof stress was 110 ksi (758.3 MPa). Tightening was performed until the pin shoulder surface came into contact with the box shoulder surface and then further rotated 1.0 / 100.
- Test No. 1 and 3 to 6 are examples of the present invention assuming the threaded joint of the present embodiment, and the diameter Dpi of the inner peripheral edge of the pin shoulder surface is smaller than the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. Reference numeral 2 is a reference comparative example assuming a conventional threaded joint, in which the diameter Dpi of the inner peripheral edge of the pin shoulder surface was the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. 7 to 9 are comparative examples in which the diameter Dpi of the inner peripheral edge of the pin shoulder surface was the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. 2 Specific evaluation of sealing performance is shown in Test No. 2 was used as a reference. That is, the test No. In the test No. 2, the seal contact force when the external pressure and the compressive load were applied and the seal contact force when the external pressure alone was applied were set as reference (1.00). No. 2 for each of the test Nos. Were compared.
- Table 1 shows the test results.
- the results shown in Table 1 show the following. Test No. of the present invention example. In Test Nos. 1 and 3 to 6, Test Nos. In comparison with No. 2, the sealing performance was improved. This is because the diameter Dpi of the inner peripheral edge of the pin shoulder surface was smaller than the diameter Dbi of the inner peripheral edge of the box shoulder surface. In particular, the test No. In the cases of 1 and 3 to 6, the sealing performance is further improved. This is because the thickness tp of the pin shoulder region is 60% or more of the thickness t of the tube body of the pin, and the thickness of the pin seal portion is effectively increased. Further, the thickness tb of the box shoulder region is 55% or less of the thickness t of the tube body of the pin, and the area of the shoulder contact surface is effectively small.
- the sealing performance was lower than that of No. 2. This is because the diameter Dpi of the inner peripheral edge of the pin shoulder surface is the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- the thickness tp of the pin shoulder region did not reach 60% of the thickness t of the tube body of the pin, so that the thickness of the pin seal portion was reduced.
- Example 2 [Test condition] In Example 2, the same FEM analysis as in Example 1 was performed. In particular, in Example 2, the inclination angle of the shoulder surface was set to 5 °. Other common conditions were the same as those in Example 1 described above. The changed dimensional conditions (diameter Dpi of the inner peripheral edge of the pin shoulder surface and diameter Dbi of the inner peripheral edge of the box shoulder surface) are as shown in Table 2 below.
- Test No. Reference numerals 10 and 12 to 15 are examples of the present invention assuming the threaded joint of the present embodiment, and the diameter Dpi of the inner peripheral edge of the pin shoulder surface is smaller than the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. Reference numeral 11 is a reference comparative example assuming a conventional threaded joint, in which the diameter Dpi of the inner peripheral edge of the pin shoulder surface was the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. 16 to 18 are comparative examples, in which the diameter Dpi of the inner peripheral edge of the pin shoulder surface was the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- Test No. 11 The sealing performance was evaluated in the same manner as in Example 1 above. The specific evaluation of the sealing performance is shown in Test No. 11 was used as a reference. That is, the test No. In the test No. 11, the seal contact force under the application of the external pressure and the compressive load and the seal contact force under the load of the external pressure alone were set as reference (1.00). Test No. 11 for the seal contact force of No. 11 Were compared.
- Table 2 above shows the test results.
- the results shown in Table 2 show the following. Test No. of the present invention example. In Test Nos. 10 and 12 to 15, Test Nos. As compared with No. 11, the sealing performance was improved. This is because the diameter Dpi of the inner peripheral edge of the pin shoulder surface was smaller than the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- test No. 16 to 18 reference test Nos.
- the sealing performance was lower than that of No. 11. This is because the diameter Dpi of the inner peripheral edge of the pin shoulder surface is the same as the diameter Dbi of the inner peripheral edge of the box shoulder surface.
- the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.
- the type of the threaded joint may be either a coupling type or an integral type.
- the threaded joint of the present invention can be effectively used for connecting steel pipes used as oil country tubular goods.
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Abstract
Description
[試験条件]
FEM解析では、ピンショルダ面の内周縁の直径Dpi、及びボックスショルダ面の内周縁の直径Dbiを種々変更したカップリング型ねじ継手のモデルを用いた。共通の条件は下記のとおりである。
・鋼管(ピン本体部)の寸法:7-5/8inch×1.06inch(外径193.7mm、肉厚27.0mm)
・鋼管のグレード:API規格のP110(公称降伏応力が110ksiの炭素鋼)
・ショルダ面(ピンショルダ面及びボックスショルダ面)の外周縁の直径Do:179.9mm
・ショルダ面の傾斜角:15°
・ねじピッチ:5.08mm
・荷重フランク面のフランク角:-3°
・挿入フランク面のフランク角:10°
・挿入フランク面における隙間:0.15mm
FEM解析では、締結状態のモデルにISO13679 2011年版のSeries A試験を模擬した荷重ステップ(内圧、外圧、引張荷重及び圧縮荷重)を負荷した。その荷重ステップ履歴の外圧サイクルにおける荷重点のうちの外圧及び圧縮荷重の荷重点、及び外圧のみの荷重点に着目し、それぞれの荷重点におけるシール部のシール性能を評価した。ここでは、外圧及び圧縮荷重の負荷時のシール接触力[N/mm]、及び外圧のみの負荷時のシール接触力[N/mm]を調査した。ここでいうシール接触力とは、「シール面同士の平均接触面圧」×「接触幅」の値であり、この値が高いほどシール性能が良いことを意味する。
上記の表1に試験結果を示す。表1に示す結果から、次のことが示される。本発明例の試験No.1及び3~6では、基準となる比較例の試験No.2と比べ、シール性能が向上した。これは、ピンショルダ面の内周縁の直径Dpiがボックスショルダ面の内周縁の直径Dbiよりも小さかったことに起因する。特に、試験No.1及び3~6では、シール性能が一層向上する。これは、ピンショルダ領域の厚さtpがピンの管本体の肉厚tの60%以上であり、ピンシール部の肉厚が有効に厚くなったことに起因する。また、ボックスショルダ領域の厚さtbがピンの管本体の肉厚tの55%以下であり、ショルダ接触面の面積が有効に小さかったことに起因する。
[試験条件]
実施例2では、上記の実施例1と同様のFEM解析を実施した。特に、実施例2では、ショルダ面の傾斜角を5°にした。それ以外に共通の条件は、上記の実施例1と同じであった。変更した寸法条件(ピンショルダ面の内周縁の直径Dpi、及びボックスショルダ面の内周縁の直径Dbi)は下記の表2のとおりである。
上記の実施例1と同様にシール性能を評価した。シール性能の具体的な評価は試験No.11を基準にして行った。つまり、試験No.11における外圧及び圧縮荷重の負荷時のシール接触力、及び外圧のみの負荷時のシール接触力をそれぞれ基準(1.00)とし、試験No.11のシール接触力に対する各試験No.のシール接触力の比率を比較した。
上記の表2に試験結果を示す。表2に示す結果から、次のことが示される。本発明例の試験No.10及び12~15では、基準となる比較例の試験No.11と比べ、シール性能が向上した。これは、ピンショルダ面の内周縁の直径Dpiがボックスショルダ面の内周縁の直径Dbiよりも小さかったことに起因する。
11 管本体
12 ショルダ面
12a 内周縁
12b 外周縁
13 シール面
14 雄ねじ部
15 ピンシール部
20 ボックス
21 管本体
22 ショルダ面
22a 内周縁
22b 外周縁
23 シール面
24 雌ねじ部
30 ショルダ接触面
Do ショルダ面の外周縁の直径
Dpi ピンショルダ面の内周縁の直径
Dbi ボックスショルダ面の内周縁の直径
tp ピンショルダ領域の厚さ
tb ボックスショルダ領域の厚さ
t ピンの管本体の肉厚
CL 管軸
Claims (4)
- 管状のピンと管状のボックスとからなる鋼管用ねじ継手であって、
前記ピンは、前記ピンの先端から前記ピンの管本体に向けて順に、環状のショルダ面と、前記ピンの前記ショルダ面に隣接する環状のシール面と、雄ねじ部とを含み、
前記ボックスは、前記ボックスの管本体から前記ボックスの先端に向けて順に、環状のショルダ面と、前記ボックスの前記ショルダ面に隣接する環状のシール面と、雌ねじ部とを含み、
前記ピン及び前記ボックスそれぞれの前記ショルダ面は、管軸に垂直な面から前記ピンのねじ込み進行方向に傾倒し、
前記ピンの前記ショルダ面の内周縁の直径が、前記ボックスの前記ショルダ面の内周縁の直径よりも小さい、鋼管用ねじ継手。 - 請求項1に記載の鋼管用ねじ継手であって、
前記管軸に垂直な面に対する前記ピン及び前記ボックスそれぞれの前記ショルダ面の傾斜角が5°~20°である、鋼管用ねじ継手。 - 請求項1又は請求項2に記載の鋼管用ねじ継手であって、
前記ピンの前記ショルダ面を前記管軸に垂直な面に投影したときに現れる環状のピンショルダ領域の厚さが、前記ピンの前記管本体の肉厚の60%以上である、鋼管用ねじ継手。 - 請求項1~請求項3のいずれか1項に記載の鋼管用ねじ継手であって、
前記ボックスの前記ショルダ面を前記管軸に垂直な面に投影したときに現れる環状のボックスショルダ領域の厚さが、前記ピンの前記管本体の肉厚の20%以上55%以下である、鋼管用ねじ継手。
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
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EP19851508.2A EP3842680A4 (en) | 2018-08-24 | 2019-08-01 | SCREW CONNECTION FOR STEEL PIPES |
RU2020141433A RU2762926C1 (ru) | 2018-08-24 | 2019-08-01 | Резьбовое соединение для стальных труб |
CA3109443A CA3109443C (en) | 2018-08-24 | 2019-08-01 | Threaded connection for steel pipes |
MX2020013350A MX2020013350A (es) | 2018-08-24 | 2019-08-01 | Conexion roscada para tubos de acero. |
US17/056,811 US11774014B2 (en) | 2018-08-24 | 2019-08-01 | Threaded connection for steel pipes |
JP2020538269A JP7065977B2 (ja) | 2018-08-24 | 2019-08-01 | 鋼管用ねじ継手 |
CN201980054771.XA CN112585389A (zh) | 2018-08-24 | 2019-08-01 | 钢管用螺纹接头 |
BR112020024954-8A BR112020024954B1 (pt) | 2018-08-24 | 2019-08-01 | Conexão roscada para tubos de aço |
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JP2018157837 | 2018-08-24 | ||
JP2018-157837 | 2018-08-24 |
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PCT/JP2019/030172 WO2020039875A1 (ja) | 2018-08-24 | 2019-08-01 | 鋼管用ねじ継手 |
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US (1) | US11774014B2 (ja) |
EP (1) | EP3842680A4 (ja) |
JP (1) | JP7065977B2 (ja) |
CN (1) | CN112585389A (ja) |
AR (1) | AR116341A1 (ja) |
CA (1) | CA3109443C (ja) |
MX (1) | MX2020013350A (ja) |
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WO (1) | WO2020039875A1 (ja) |
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2019
- 2019-08-01 EP EP19851508.2A patent/EP3842680A4/en active Pending
- 2019-08-01 MX MX2020013350A patent/MX2020013350A/es unknown
- 2019-08-01 JP JP2020538269A patent/JP7065977B2/ja active Active
- 2019-08-01 CA CA3109443A patent/CA3109443C/en active Active
- 2019-08-01 US US17/056,811 patent/US11774014B2/en active Active
- 2019-08-01 RU RU2020141433A patent/RU2762926C1/ru active
- 2019-08-01 CN CN201980054771.XA patent/CN112585389A/zh active Pending
- 2019-08-01 WO PCT/JP2019/030172 patent/WO2020039875A1/ja active Application Filing
- 2019-08-21 AR ARP190102379A patent/AR116341A1/es active IP Right Grant
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EP3842680A4 (en) | 2022-04-27 |
BR112020024954A2 (pt) | 2021-03-09 |
MX2020013350A (es) | 2021-03-09 |
US11774014B2 (en) | 2023-10-03 |
CA3109443A1 (en) | 2020-02-27 |
AR116341A1 (es) | 2021-04-28 |
JP7065977B2 (ja) | 2022-05-12 |
JPWO2020039875A1 (ja) | 2021-06-10 |
CA3109443C (en) | 2023-06-27 |
RU2762926C1 (ru) | 2021-12-23 |
EP3842680A1 (en) | 2021-06-30 |
US20210164593A1 (en) | 2021-06-03 |
CN112585389A (zh) | 2021-03-30 |
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