专利摘要:
THREADED CONNECTION FOR STEEL PIPE. The present invention relates to a threaded coupling for steel tubes which comprises: a box which is an opening end of a second tube material; and a circular truncated cone-shaped pin that is an end of a first tube material and into which the box is inserted. The pin has a male thread section that is a tapered thread and a sealing section that includes a tapered surface. The housing has a female thread section that is a tapered thread and a sealing section that includes a tapered surface. In the state prior to the start of the pin and housing coupling, the minimum diameter of the tapered surface of the pin is less than the maximum diameter of the tapered surface of the box
公开号:BR112016004473B1
申请号:R112016004473-8
申请日:2014-09-04
公开日:2020-12-29
发明作者:Masaaki Sugino;Tatsuya Yamamoto;Yukihiro Nishikawa
申请人:Vallourec Oil And Gas France;Nippon Steel Corporation;
IPC主号:
专利说明:

FIELD OF THE TECHNIQUE OF THE INVENTION
[001] The present invention relates to a threaded connection for a steel pipe.
[002] Priority is claimed over patent application No. JP 2013-184717, filed on Friday, September 6, 2013, the content of which is incorporated into this document as a reference. RELATED TECHNIQUE
[003] In an oil well or a natural gas well (hereinafter collectively referred to as an "oil well"), steel tubes that are sequentially connected are used as oil well tubes, such as a liner or pipe. In general, in this type of threaded connection, a connection that has only a tapered thread defined by the American Petroleum Institute standard is applied. The threaded connection is configured by a first tube that has a conical male thread portion and a second tube that has a conical female thread portion. The male threaded portion of the first pipe is threaded into the female threaded portion of the second pipe and, therefore, the first pipe and the second pipe are connected to each other.
[004] Threaded connections for a steel tube are roughly classified into two types: a coupling type and an integral type. In a coupling type case, the first tube is a steel tube and the second tube is a coupling (short tube). In this case, male thread portions are formed on both end portions of the steel tube and female thread portions are formed on both end portions of the coupling. That is, in the coupling type, steel tubes adjacent to each other are connected to each other through the coupling.
[005] However, in a case of the integral type, both the first tube and the second tube are steel tubes and the coupling is not used. In this case, the male thread portion is formed on one end portion of the steel tube and the female thread portion is formed on the other end portion. That is, in the integral type, the steel tubes adjacent to each other are directly connected to each other without the use of the coupling.
[006] In general, the connection portion of the first tube in which the male thread portion is formed includes an element inserted in the female thread portion and is therefore referred to as a pin. At the same time, the connection portion of the second pipe on which the female threaded portion is formed includes an element that receives the male threaded portion and is therefore referred to as a box. Hereinafter, the connecting portion which includes the male threaded portion is also referred to as the pin and the connecting portion which includes the female threaded portion is also referred to as the housing.
[007] In the threaded connection for a steel tube, the male threaded portion of the pin is threaded into the female threaded portion of the housing and the male threaded portion and the female threaded portion are adjusted in close contact with each other . In this way, in the threaded connection of the API standard that does not have a sealing surface (surface without thread), the male thread portion and the female thread portion are adjusted in contact with each other and, therefore, the performance of the sealing and pressure resistance of the threaded connection are ensured.
[008] In recent years, according to an increase in the depth and gravity of oil well circumstances in which the threaded connection is used, particularly in a threaded connection of a steel pipe that has a large diameter used in a coating, improved sealing performance and pressure resistance is required. In this way, the threadless surface (sealing surface) is provided on an external surface of the pin and an internal surface of the corresponding housing and a metal touch seal that fits the sealing surfaces is widely used as a sealing mechanism.
[009] In the metal touch seal, an outer diameter of the pin is configured to be slightly larger than an inner diameter of the housing (this difference in diameter is referred to as a "seal interference amount"). In the metal touch seal, the pin and box are adjusted and interfere with each other in a radial direction and an elastic recovery force to return to the original diameter is generated between the box in which the diameter is increased and the pin in which the diameter is decreased. The resilient recovery force makes the sealing surface firmly in contact with sealing surfaces.
[0010] In order to improve sealing performance and resistance to pressure, threaded connections disclosed in Patent Documents 1 to 3 are suggested.
[0011] For example, a threaded connection for a tube disclosed in Patent Document 1, a sealing portion is provided in a position away from a shoulder, a shoulder portion extends from the sealing portion up to a shoulder portion (support surface) and, therefore, sealing performance and pressure resistance are improved.
[0012] In threaded connections for a steel pipe disclosed in Patent Documents 2 and 3, a first pipe (pin) and a second pipe (box) include conical threads (male thread portion and female thread portion) that they are adjusted in close contact with each other and a sealing surface and a support surface. In this way, in the threaded connections for a steel tube revealed in Patent Documents 2 and 3, the sealing surfaces of the pin and the housing come in firm contact with each other according to the threading of the pin and a seal ( metal sealing) by a metal contact is formed. In addition, the supporting surfaces of the pin and the housing come into contact with each other in accordance with the threading of the pin and the supporting surfaces take on the role of a plug that limits the threading of the pin and a hole to apply a load in a direction opposite to a threading direction, that is, a so-called axial force of composition of a thread in the male thread portion. LIST OF QUOTES PATENT DOCUMENT
[0013] Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2012-149760.
[0014] Patent Document 2: PCT International Publication No. WO 2011/060894.
[0015] Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2012-506000. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION
[0016] In an oil well location, when two tubes are connected to each other, a pin is threaded into a box using a composition device called a power tongue. At that time, since a composition torque and threading state (an increase in the number of composition twists) was in a relationship shown in Figure 8, the threading state from pin to housing (a state of composition between the pin and the box) is understood through the observation (measurement) of the composition torque required for threading.
[0017] When the threading of the pin to the box is carried out normally, as shown in Figure 8, the composition torque is increased in a smooth and monotonous manner according to the threading state (the increase in the number of composition twists) . In addition, the support surfaces come into contiguous contact with each other immediately before threading is completed and therefore the compounding torque is increased abruptly (this is called shouldering, due to the shoulder-like shape).
[0018] At the same time, when an abnormality such as wear occurs in a threading process, the composition torque is excessively increased before "shouldering" occurs.
[0019] In the threaded connection for a tube disclosed in Patent Document 1, the sealing surfaces of the pin and housing slide when coming into contact with each other in a narrow contact width and a contact pressure of high medium in a process in which the threaded connection is threaded and compounded and therefore the occurrence of wear is not easily avoided. Additionally, in the threaded connections for a steel tube disclosed in Patent Documents 2 and 3, even when the pinning of the pin to the box is carried out normally, the compounding torque is excessively increased or changed irregularly (the so-called the composition torque occurs) in the threading process.
[0020] Figure 10 shows a schematic view that shows a relationship between the number of composition twists and the composition torque when the composition torque prominence occurred. As shown in Figure 10, if the composition torque prominence occurred in the pin threading process, it is difficult to correctly understand the pin threading status. In this way, it can be determined that the threading is completed at the time of the prominence. If the completion of threading is erroneously determined, threading is not sufficient and there is concern that the connection between the first pipe and the second pipe may be incomplete.
[0021] Thus, the present invention was made in consideration of the circumstances mentioned above and an objective of the same is to provide a threaded connection for a steel pipe with the ability to avoid the prominence of a composition torque that occurred when a pin and a box are made up. MEANS TO SOLVE THE PROBLEM
[0022] In order to solve the problems described above, the present invention adopts the following.
[0023] (1) According to a first aspect of the present invention, a threaded connection is provided for a steel pipe that connects a first pipe and a second pipe, the threaded connection including: a box that is a opening end of the second tube and a pin in the shape of a truncated cone that is an end of the first tube and is inserted in the box, the pin including a male thread portion which is a tapered thread and a sealing section which includes a tapered surface and the housing includes a female thread portion which is a tapered thread and a seal portion which includes a tapered surface and where when the male threaded portion and the female threaded portion are composed of threading, a root of the male thread portion and a crest of the female thread portion come into contact with each other after the sealing portion of the pin and the sealing portion of the housing come into contact with each other. the other, in a process of composition and a state prior to c omposition, a minimum diameter of the tapered surface of the pin is less than a maximum diameter of the tapered surface of the box.
[0024] (2) In the aspect according to (1) above, the pin portion of the pin can be provided on each of a pin point side of the male thread portion and a base side of the male thread portion pin.
[0025] (3) In the aspect according to (1) or (2) above, the pin can additionally include a portion R which is provided on a pin end side of the sealing portion of the pin and the box can include additionally a portion R which is provided on a tip side of the housing of the housing sealing portion.
[0026] (4) In the aspect according to any one of (1) to (3) above, the male thread portion may be divided into a plurality of male thread portions along a geometrical axis direction of tube of the first tube and the sealing portion of the pin can be provided additionally between the male thread portions adjacent to each other in the direction of the tube axis.
[0027] (5) In the aspect according to any one of (1) to (4) above, the pin may additionally include a support surface which is provided on a tip or a base of the pin.
[0028] (6) In the aspect according to any one of (1) to (5) above, each one of the first and the second tubes can be a steel tube.
[0029] (7) In the aspect according to (6) above, an outer diameter of a body of the first tube can be 190 mm or more, an outer diameter of a body of the second tube can be 190 mm or more and in the In the pre-composition state, an outer diameter of the box may be more than 100% of the outer diameter of the body of the first tube and be less than 104% of the outer diameter of the body of the first tube.
[0030] (8) In the aspect according to (7) above, in the previous state of the composition, a difference between the minimum diameter of the conical surface of the pin and the maximum diameter of the conical surface of the box can be more than 0% of the outer diameter of the body of the first tube, and be 0.3% or less of the outer diameter of the body of the first tube.
[0031] (9) In the aspect according to any one of (1) to (5) above, the first tube can be a steel tube and the second tube can be a coupling.
[0032] (10) In the aspect according to (9) above, an outside diameter of a body of the first tube can be 190 mm or more.
[0033] (11) In the aspect according to (10) above, in the previous state of the composition, a difference between the minimum diameter of the conical surface of the pin and the maximum diameter of the conical surface of the box can be more than 0% of the outer diameter of the body of the first tube, and be 0.3% or less of the outer diameter of the body of the first tube. EFFECTS OF THE INVENTION
[0034] According to each aspect, it is possible to avoid the prominence of a composition torque that occurred when a pin and a box are composed. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1A is a longitudinal sectional view showing a main portion of a threaded connection for a steel tube according to a first embodiment of the present invention and showing a state prior to a pin and a box being composed.
[0036] Figure 1B is a view showing the beginning of the composition between the pin and the box in the threaded connection for a steel tube shown in Figure 1A.
[0037] Figure 1C is a view showing a state in which the composition between the pin and the housing is completed at the threaded connection for a steel tube shown in Figure 1A.
[0038] Figure 2A is an enlarged view of Figure 1B showing a tip side of the pin.
[0039] Figure 2B is an enlarged view of Figure 1B showing a base side of the pin.
[0040] Figure 3A is an enlarged view showing a portion indicated by X in Figure 1B and showing a male thread portion and a female thread portion.
[0041] Figure 3B is an enlarged view showing a portion indicated by Y in Figure 1C and showing the male thread portion and the female thread portion.
[0042] Figure 4A is a view showing a state during the composition between the pin and the box in the threaded connection for a steel tube shown in Figure 1A and shows the tip side of the pin.
[0043] Figure 4B is an enlarged view of Figure 1C and shows the tip side of the pin.
[0044] Figure 5A is a view that shows the state during the composition between the pin and the box in the threaded connection for a steel tube shown in Figure 1A and shows the base side of the pin.
[0045] Figure 5B is an enlarged view of Figure 1C and shows the base side of the pin.
[0046] Figure 6 is a longitudinal sectional view showing a modified example of the threaded connection for a steel tube according to the first embodiment of the present invention.
[0047] Figure 7 is a longitudinal sectional view showing a threaded connection for a steel tube according to a second embodiment of the present invention.
[0048] Figure 8 is a schematic view showing a relationship between the number of composition twists and a composition torque in the threaded connection for a steel pipe according to the first embodiment of the present invention.
[0049] Figure 9A is an enlarged view showing the threaded connection for a steel tube in which the prominence of the composition torque has occurred and shows the tip side of the pin.
[0050] Figure 9B is an enlarged view showing the threaded connection for a steel tube in which the prominence of the composition torque occurred and shows the base side of the pin.
[0051] Figure 10 is a schematic view showing the relationship between the number of composition twists and the composition torque in the threaded connection for a steel pipe in which the composition torque prominence occurred. MODALITIES OF THE INVENTION
[0052] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. In addition, in this specification and in the drawings, the same numerical references are attributed to the same components that have substantially the same function and configuration and coincident descriptions of them are omitted. FIRST MODE EXAMPLE OF SCREWED CONNECTION CONFIGURATION FOR STEEL PIPE
[0053] First, a threaded connection 1 for a steel pipe (hereinafter, also referred to simply as "threaded connection") according to a first embodiment of the present invention will be described. Figures 1A to 1C are longitudinal sectional views showing the threaded connection 1 for a steel tube according to the first embodiment. In addition, Figure 1A is a view showing a state prior to pin 20 being threaded into box 30 (a state prior to pin 20 and box 30 being composed), Figure 1B is a view showing a state prior to threading of pin 20 (a state prior to the composition between pin 20 and box 30) and Figure 1C is a view showing a state in which threading of pin 20 is completed (a state in which the composition between pin 20 and box 30 is completed). The composition between pin 20 and box 30 will be described below.
[0054] As shown in Figures 1A to 1C, the screw connection 1 for a steel pipe according to the first modality is used to connect (join) an upper pipe 2 (a first pipe) and a lower pipe 3 ( a second tube) in series along a direction of a CL tube axis (longitudinal direction of a tube, a connection direction or a vertical direction: see Figure 1A). The screw connection 1 for a steel tube includes a truncated cone-shaped pin 20 which is provided at one end (bottom end) of the top tube 2 and a box 30 which is provided at an opening end (top end) of the bottom tube 3. Additionally, the screw connection 1 for a steel tube is a threaded connection of the integral type in which the top tube 2 and the bottom tube 3 are steel tubes. In addition, hereinafter, the direction of the pipe axis CL is called a "pipe axis direction".
[0055] As shown in Figure 1A, on the truncated cone-shaped pin 20 provided at the lower end (one end) of the upper tube 2, a tip surface 25, a first portion R 26 (a first curved portion), a first sealing portion 22, a male thread portion 21, a second portion R 27 (a second curved portion), a second sealing portion 23 and a supporting surface 24 are provided in that order from one side to the other. pin 20. In addition, in Figure 1A, the first portion R 26 and the second portion R 27 are not shown. The male thread portion 21 is a tapered thread and is spiral formed on an outer circumferential surface of pin 20. The support surface 24 is an annular surface along a radial direction (a direction perpendicular to the axis direction geometric shape) and is slightly tilted in the radial direction. For example, preferably, an angle of inclination of the support surface 24 is less than or equal to 20 ° and, more preferably, it is 15 °. Here, the tapered thread means a thread that is provided on an outer surface or an inner surface of a truncated cone.
[0056] In addition, in Figure 1A, the bottom side is the tip side (front end side) on pin 20 and the top side is the tip side (front end side) on box 30. In addition, the opposite sides of the tip sides of pin 20 and box 30 are called base sides (rear end sides). Hereinafter, these are applied similarly to all drawings in this specification.
[0057] Furthermore, as shown in Figure 1A, in the box 30 provided at the opening end (upper end) of the lower tube 3, a base surface 35, a third sealing portion 32, a third R 36 portion (a third curved portion), a female thread portion 31, a fourth sealing portion 33, a fourth R 37 portion (a fourth curved portion) and a support surface 34 are provided on a base side of the housing 30. In addition, on the Figure 1A, the third portion R 36 and the fourth portion R 37 are not shown. Similar to the male thread portion 21, the female thread portion 31 is a tapered thread and is spiral-shaped on an internal circumferential surface of the housing 30.
[0058] The third sealing portion 32, the female thread portion 31, the fourth sealing portion 33 and the support surface 34 of the housing 30 are provided to correspond to the first sealing portion 22, to the male thread portion 21, the second sealing portion 23 and the support surface 24 of the pin 20, respectively. In addition, despite being described below, the thread teeth of the male thread portion 21 of pin 20 and the thread teeth of the female thread portion 31 of box 30 have an inverted trapezoid shape (hereinafter referred to as of a dovetail shape) when viewed from a cross section parallel to the direction of the pipe's geometric axis and interlocking with each other.
[0059] Figure 2A is an enlarged view of Figure 1B and shows the tip side of pin 20 (the base side of box 30). As shown in Figure 2A, the first sealing portion 22 includes a first tapered surface 22a (a first tapered sealing surface) and a first bend surface 22b that are formed on the outer circumferential surface of the pin 20.
[0060] When pin 20 is seen from the cross section parallel to the direction of the pipe's geometric axis, the first conical surface 22a is inclined at a predetermined angle (taper angle). That is, the first conical surface 22a forms a truncated cone surface in which the diameter is gradually decreased from the base side of the pin 20 towards the tip side on the outer circumferential surface of the pin 20. For example, preferably, the tapered angle of the tapered surface 22a is 2 ° to 21 °, more preferably, it is 2 ° to 15 ° and, most preferably, it is 2 ° to 7 °.
[0061] When pin 20 is seen from the cross section parallel to the direction of the pipe's geometric axis, the first curvature surface 22b is formed in a curve that is contracted in a predetermined curvature such as an arc and smoothly connects the first sealing portion 22 (first tapered surface 22a) and male thread portion 21. In this way, the first bend surface 22b is provided, the first sealing portion 22 (first tapered surface 22a) and the male threads 21 are smoothly connected to each other and therefore it is possible to prevent wear at the time of composition. In addition, the first curvature surface 22b may include an arc and may include a curve other than an arc.
[0062] The first portion R 26 (a front portion R of pin 20) of pin 20 has a light and small rounded shape (refer to an oblique line portion of Figure 2A) and smoothly connects the first seal portion 22 and the surface edge 25. That is, the first R 26 portion (first curved portion) includes a surface (curvature surface or R surface) that corresponds to a circumferential surface of a rotating body that is obtained by rotating a curve it contracted at a predetermined curvature such as an arc around the pipe CL axis. In this way, the first portion R 26 is supplied and smoothly connects the first sealing portion 22 and the tip surface 25 and, therefore, it is possible to prevent wear at the time of composition. In addition, the first portion R 26 may include an arc and may include a curve in place of an arc.
[0063] In addition, as shown in Figure 2A, the third sealing portion 32 of box 30 includes a third tapered surface 32a (a third tapered sealing surface). When the box 30 is seen from the cross section parallel to the direction of the geometric axis of the tube, the third conical surface 32a is inclined at a predetermined angle (conical angle). That is, the third conical surface 32a forms a truncated cone surface in which the diameter is gradually decreased from the base side of the box 30 towards the tip side on the inner circumferential surface of the box 30. For example, preferably, the tapered angle of the third tapered surface 32a is 2 ° to 21 °, more preferably, it is 2 ° to 15 ° and, most preferably, it is 2 ° to 7 °.
[0064] The third portion R 36 (a rear portion R of box 30) of box 30 has a smooth, large rounded shape (see oblique line portion of Figure 2A) and smoothly connects third seal portion 32 and an end rear 31e of the female thread portion 31 (not shown in Figure 2A). That is, the third portion R 36 (third portion curved) includes a surface (curvature surface or surface R) that corresponds to a circumferential surface of a rotating body that is obtained by rotating a contracted curve to a predetermined curvature such as an arc around the CL tube geometric axis. In this way, the third portion R 36 is supplied and smoothly connects the third sealing portion 32 and the rear end 31e of the female thread portion 31 and, therefore, it is possible to prevent wear at the time of composition. In addition, the third portion R 36 may include an arc and may include a curve in place of an arc.
[0065] The tapered angle of the first tapered surface 22a of pin 20 and the tapered angle of the third tapered surface 32a of box 30 are constant. In addition, the tapered angle of the first tapered surface 22a is substantially the same as the tapered angle of the third tapered surface 32a. Here, the fact that the tapered angles are substantially equal to each other means that a difference of ± 0.75 ° is allowed.
[0066] Furthermore, the third conical surface 32a is longer than the first conical surface 22a. That is, a distance between a front end 32b and a rear end 32c on the third conical surface 32a is longer than a distance between a front end 22c and a rear end 22d on the first conical surface 22a.
[0067] In addition, as shown in Figure 2A, the first sealing portion 22, the third sealing portion 32, the first portion R 26 and the third portion R 36 are non-threaded portions.
[0068] Furthermore, preferably, the third sealing portion 32 is configured only by the third conical surface 32a. In this case, since the conical surfaces come into contact with each other with a wider surface area, an average contact pressure can be suppressed. As a result, the wear resistance performance can be improved.
[0069] Figure 2B is an enlarged view of Figure 1B and shows the base side of pin 20 (the tip side of box 30). As shown in Figure 2B, the second sealing portion 23 of pin 20 includes a second tapered surface 23a (a second tapered sealing surface) formed on the outer circumferential surface of pin 20.
[0070] When pin 20 is seen from the cross section parallel to the direction of the pipe's geometric axis, the second conical surface 23a is inclined at a predetermined angle (conical angle). That is, the second conical surface 23a forms a truncated cone surface in which the diameter is gradually decreased from the base side of the pin 20 towards the tip side on the outer circumferential surface of the pin 20. For example preferably, the tapered angle of the second tapered surface 23a is 2 ° to 21 °, more preferably, 2 ° to 15 ° and, even more preferably, 2 ° to 7 °.
[0071] The second portion R 27 (a rear portion R of pin 20) of pin 20 has a smooth, large rounded shape (see an oblique line portion of Figure 2B) and smoothly connects the second seal portion 23 and the end rear 21e of the male thread portion 21 (not shown in Figure 2B). That is, the second R 27 portion (second curved portion) includes a surface (curvature surface or R surface) that corresponds to a circumferential surface of a rotating body that is obtained by turning a contracted curve in a predetermined curvature such as an arc around the pipe axis. In this way, the second portion R 27 is provided and smoothly connects the second sealing portion 23 and the rear end 21e of the male thread portion 21 and, therefore, it is possible to prevent wear at the time of composition. In addition, the second portion R 27 can include an arc and can include a curve instead of an arc.
[0072] The fourth sealing portion 33 of the box 30 includes a fourth tapered surface 33a (fourth tapered sealing surface) and a second curvature surface 33b which are formed on the inner circumferential surface of the box 30.
[0073] When the box 30 is seen from the cross section parallel to the direction of the geometric axis of the tube, the fourth conical surface 33a is inclined at a predetermined angle (conical angle). That is, the fourth conical surface 33a forms a truncated cone surface in which the diameter is gradually decreased from the base side of the box 30 towards the tip side on the inner circumferential surface of the box 30. For example, preferably, the taper angle of the fourth taper surface 33a is 2 ° to 21 °, more preferably it is 2 ° to 15 ° and, even more preferably, it is 2 ° to 7 °.
[0074] When box 30 is seen from the cross section parallel to the direction of the pipe's geometric axis, the second curvature surface 33b forms a curve that is contracted to a predetermined curvature such as an arc and smoothly connects the fourth sealing portion 33 (fourth tapered surface 33a) and female thread portion 31 (not shown in Figure 2B). In this way, the second curvature surface 33b is provided and smoothly connects the fourth sealing portion 33 (fourth conical surface 33a) and the female thread portion 31 and, therefore, it is possible to prevent wear at the time of composition. In addition, the second curvature 33b can include an arc and can include a curve in place of an arc.
[0075] The fourth R 37 portion of box 30 (front R portion of box 30) has a smooth, small round shape (see an oblique portion of Figure 2B) and smoothly connects the fourth seal portion 33 and the support surface 34 of box 30. That is, the fourth portion R 37 (fourth curved portion) includes a surface (curvature surface or surface R) that corresponds to a circumferential surface of a rotating body that is obtained by of the rotation of a contracted curve in a predetermined curvature such as an arc around the geometric axis of tube CL. In this way, the fourth portion R 37 is provided and the fourth sealing portion 33 and the support surface 34 of the housing 30 are smoothly connected to each other and, therefore, it is possible to prevent wear at the time of composition. In addition, the fourth portion R 37 may include an arc and may include a curve in place of an arc.
[0076] The tapered angle of the second tapered surface 23a of pin 20 and the tapered angle of the fourth tapered surface 33a of box 30 are constant. In addition, the tapered angle of the second tapered surface 23a is substantially the same as the tapered angle of the fourth tapered surface 33a. Here, the fact that the tapered angles are substantially equal to each other means that a difference of ± 0.75 ° is allowed.
[0077] Furthermore, the second conical surface 23a is longer than the fourth conical surface 33a. That is, a distance between a front end 33c and a rear end 33d on the fourth conical surface 33a is shorter than a distance between a front end 23b and a rear end 23c on the second conical surface 23a.
[0078] In addition, as shown in Figure 2B, the second sealing portion 23, the fourth sealing portion 33, the second portion R 27 and the fourth portion R 37 are non-threaded portions.
[0079] Furthermore, preferably, the second sealing portion 23 of the pin 20 is configured only by the second conical surface 23a. In this case, since the conical surfaces come into contact with each other with a wider surface area, an average contact pressure can be suppressed. As a result, the wear resistance performance can be improved.
[0080] Figure 3A is an enlarged view showing a portion indicated by X in Figure 1B and showing the male thread portion 21 and the female thread portion 31. As shown in Figure 3A, the male thread portion 21 includes a ridge 21c, a root 21d, a penetrating flank surface 21a and a loading flank surface 21b. Since the pin 20 has a conical shape, the diameters of the crest 21c and the root 21d are changed along the direction of the pipe geometric axis. Crest 21c and root 21d are parallel to the direction of the pipe geometric axis. A curved connection portion is provided on both the crest 21c and the root 21d.
[0081] Additionally, the male thread portion 21 has a dovetail shape in which a width (a length of the ridge 21c in the direction of the pipe axis) of the ridge 21c is wider than a width of one base portion (a portion of the root of a donut).
[0082] In addition, as shown in Figure 3A, the female thread portion 31 includes a ridge 31c, a root 31d, a penetrating flank surface 31b and a loading flank surface 31a. Since the box 30 has a conical shape, the diameters of the crest 31c and that of the root 31d are changed along the direction of the pipe geometric axis. The ridge 31c and the root 31d are parallel to the direction of the pipe axis. A curved connection portion is provided on the crystal 31c and the root 31d.
[0083] Additionally, similar to the male thread portion 21, the female thread portion 31 also has a dovetail shape (inverted trapezoid shape).
[0084] The ridges 21c and 31c and the roots 21d and 31d have widths that are changed along the direction of the geometric axis of the tube. For example, a width L of the ridge 21c is shown as follows. L = Lo + Ax ... (Equation 1)
[0085] Here, L0 to A are constant, x is a position along the direction of the pipe axis and the width L is measured to be parallel to the direction of the pipe axis.
[0086] In the threaded connection 1 for a steel tube, the width of the crest 21c of the male thread portion 21 is decreased along the direction of the pipe axis (that is, the width of the crest is decreased from the base side of pin 20 towards the tip side) and the root width 21d of the male thread portion 21 is increased along the direction of the pipe axis (that is, the root width is increased from from the base side of pin 20 towards the tip side). In addition, the width of the crest 31c of the female thread portion 31 is increased along the direction of the pipe axis (i.e., the width of the crest is increased from the tip side of the housing 30 towards the base side ) and the root width 31d of the female thread portion 31 is decreased along the direction of the pipe axis (i.e., the root width is decreased from the tip side of the box 30 towards the base side) .
[0087] Next, a threading process of pin 20 in box 30 (a process of a composition between pin 20 and box 30) will be described.
[0088] When the upper tube 2 and the lower tube 3 are connected to each other (when pin 20 and box 30 are composed), first, as shown in Figure 1A, pin 20 is inserted in box 30 along the direction of pipe geometric axis. Then, the pin 20 is relatively rotated relative to the box 30 around the geometric axis of tube CL. In this way, pin 20 is threaded in box 30 along the direction of the pipe axis and the thread of pin 20 (the composition between pin 20 and box 30) progresses. That is, the threading of pin 20 to box 30 progresses from the base side of pin 20 towards the tip side (a direction of progression of the threading).
[0089] As shown in Figure 3A, in a state in which the composition between pin 20 and box 30 begins, the penetrating flank surface 21a of the male thread portion 21 comes into contact with the flank surface of penetration 31b of the female thread portion 31 with all the weight of the upper tube 2. In other words, in the state in which the composition begins, except for the penetration flank surfaces 21a and 31b, the male thread portion 21 and the female thread portion 31 does not come into contact with each other.
[0090] If pin 20 is additionally threaded in box 30 along the direction of the pipe axis from the state in which the composition begins, which is shown in Figures 1B and 3A, the first sealing portion 22 and the second sealing portion 23 of the pin 20 come in close contact with the third sealing portion 32 and the fourth sealing portion 33 of the housing 30, respectively. If pin 20 is additionally threaded in box 30 from that state, the root 21d of the male thread portion 21 and the crest 31c of the female thread portion 31 come into contact with each other.
[0091] In addition, if pin 20 is additionally threaded in box 30, as shown in Figure 1C, the support surface 24 of pin 20 and the support surface 34 of box 30 come into contact with each other, the support surface 24 of pin 20 is pressed to the support surface 34 of box 30 and the threading of pin 20 (the composition between pin 20 and box 30) is completed. In this way, the support surfaces 24 and 34 are in contiguous contact with each other, the threading of pin 20 is limited and a load in a direction opposite to the direction of progression of the threading, that is, an axial compounding force of a thread is applied to the male thread portion 21 of pin 20.
[0092] In addition, as shown in Figure 1C, since the first sealing portion 22 and the third sealing portion 32 interfere with each other in the radial direction while in contact with each other, an structure (metal touch seal) in which at least a part of the first seal portion 22 comes in close contact with at least a part of the third seal portion 32 across the circumference. The seal by the first seal portion 22 and the third seal portion 32 assumes a role mainly of sealing an internal pressure Pin of the upper tube 2 and the lower tube 3.
[0093] Similarly, since the second sealing portion 23 and the fourth sealing portion 33 interfere with each other in the radial direction while in contact with each other, a structure is obtained (metal touch seal) in which at least a part of the second seal portion 23 comes in close contact with at least a part of the fourth seal portion 33 across the circumference. The sealing by the second sealing portion 23 and the fourth sealing portion 33 assumes a role mainly of selling an external pressure Pout of the upper pipe 2 and the lower pipe 3.
[0094] Figure 3B is an enlarged view showing a portion indicated by Y in Figure 1C and showing the male thread portion and the female thread portion in a state in which the composition is complete. As shown in Figure 3B, in the state in which the composition is complete, the loading flank surface 21b of the male thread portion 21 and the loading flank surface 31a of the female thread portion 31 that opposes the loading flank surface 21b come in close contact with each other and therefore the root 21d of the male thread portion 21 and the crest 31c of the female thread portion 31 come in close contact with each other. In addition, as shown in Figure 3B, in the state in which the composition is complete, there is a gap between the penetration flank surface 21a of pin 20 and the penetration flank surface 31b of box 30 in the direction of the geometry axis tube and there is a gap between the crest 21c of the pin 20 and the root 31d of the box 30 in the radial direction.
[0095] As described above, pin 20 is threaded on box 30, the composition between pin 20 and box 30 is complete and, therefore, the upper tube 2 and the lower tube 3 are connected to each other. CAUSE OF OUTSTANDING
[0096] Next, a cause that leads to the prominence of the composition torque occurring will be described. Figures 9A and 9B are enlarged views showing a threaded connection 50 for a steel tube in which prominence occurs. Additionally, Figure 9A shows the tip side of pin 20 and Figure 9B shows the base side of pin 20.
[0097] As described above, in the state where the composition between pin 20 and box 30 begins, the penetration flank surface 21a of the male thread portion 21 and the penetration flank surface 31b of the thread portion female 31 come into contact with each other. However, except for the penetrating flank surfaces, the male thread portion 21 and the female thread portion 31 do not come into contact with each other (see Figure 3A). That is, in the state in which the composition begins, a gap exists between the root 21d of the male thread portion 21 and the crest 31c of the female thread portion 31. Additionally, gaps also exist between the crest 21c of the male thread portion 21 and the root 31d of the female thread portion 31 and between the loading flank surface 21b of the male thread portion 21 and the loading flank surface 31a of the female thread portion 31.
[0098] That is, in the state where the composition between pin 20 and 30 begins, since the male thread portion 21 of pin 20 and the female thread portion 31 of box 30 slightly mesh with each other , there is feasibility in engaging the threads. Thus, in the process in which the threading progresses, the tube geometric axis (center) of the upper tube 2 and the tube geometric axis (center) of the lower tube 3 can be misaligned with respect to each other.
[0099] In these circumstances, in a state prior to pin 20 and box 30 being composed, when pin 20 and box 30 are in the following (i) and (ii), prominence is determined to occur despite such an abnormality as wear does not occur.
[00100] (i) A diameter D1 of the front end 22c on the first tapered surface 22a of pin 20 is wider than a diameter D3 of the front end 32b on the third tapered surface 32a of box 30 (see Figure 9A). That is, the minimum diameter D1 of the first tapered surface 22a is wider than the maximum diameter D3 of the third tapered surface 32a.
[00101] (ii) A diameter D2 of the front end 23b on the second tapered surface 23a of pin 20 is wider than a diameter D4 of the front end 33c on the fourth tapered surface 33a of box 30 (see Figure 9B). That is, the minimum diameter D2 of the second conical surface 23a is wider than the maximum diameter D4 of the fourth conical surface 33a of box 30.
[00102] Here, the diameter of the conical surface is a diameter when the truncated cone shaped sealing portion of the conical surface is seen from the cross section perpendicular to the direction of the pipe's geometric axis.
[00103] In the cases of (i) and (ii), if the composition between pin 20 and box 30 progresses, the prominence of the composition torque occurs due to the following phenomenon.
[00104] If pin 20 is threaded into box 30 from the state shown in Figure 9A, the first portion R 26 of pin 20 comes into contact with the third portion R 36 of box 30 before the first sealing portion 22 of pin 20 makes contact with the third sealing portion 32 of the box 30. When the first portion R 26 and the third portion R 36 come into contact with each other, the first sealing portion 22 is not inserted smoothly into the third portion of seal 32 by the shapes and dimensions of the curvature surfaces (surfaces R) and therefore the tube axis of the upper tube 2 and the tube axis of the lower tube 3 are easily misaligned in relation to each other.
[00105] Similarly, as shown in Figure 9B, the second portion R 27 of pin 20 comes into contact with the fourth portion R 37 of box 30 before the second sealing portion 23 of pin 20 comes into contact with the fourth sealing portion 33 of the box 30. Thus, when the second portion R 27 and the fourth portion R 37 come into contact with each other, the second sealing portion 23 is not smoothly inserted into the fourth sealing portion 33 by the shapes and dimensions of the curvature surfaces (R surfaces) and therefore the tube geometric axis of the upper tube 2 and the tube geometric axis of the lower tube 3 are easily misaligned in relation to each other.
[00106] As described above, in the state where the first portion R 26 of pin 20 comes into contact with the third portion R 36 of box 30, pin 20 is threaded into box 30 while the first portion R 26 pin 20 is in unstable contact with the third portion R 36 of box 30. Similarly, in the state where the second portion R 27 of pin 20 comes into contact with the fourth portion R 37 of box 30, pin 20 is threaded into box 30 while the second portion R 27 of pin 20 unstably contacts the fourth portion R 37 of box 30. As described above, since there is viability of engaging the threads, that is between the male thread portion 21 of pin 20 and female thread portion 31 of box 30, unstable threading generates a temporary increase and an irregular variation in the torque of composition. In this way, the prominence of the composition torque occurs even when wear does not occur.
[00107] In order to avoid the prominence described above, in the threaded connection 1 for a steel pipe according to the first modality, as shown in Figure 2A, in the state before pin 20 and box 30 are composed, diameter D1 of the front end 22c on the first tapered surface 22a is less than the diameter D3 of the front end 32b on the third tapered surface 32a.
[00108] Similarly, in the threaded connection 1 for a steel tube according to the first modality, as shown in Figure 2B, in the state before pin 20 and box 30 are composed, the diameter D2 of the front end 23b on the second conical surface 23a is less than the diameter D4 of the front end 33c on the fourth conical surface 33a.
[00109] That is, in the threaded connection 1 for a steel tube according to the first modality, in the state before pin 20 and box 30 are composed, a first condition (D1 <D3) in which the minimum diameter D1 of the first conical surface 22a is less than the maximum diameter D3 of the third conical surface 32a and a second condition (D2 <D4) in which the minimum diameter D2 of the second conical surface 23a is less than the maximum diameter D4 of the fourth conical surface 33a of box 30 are satisfied.
[00110] Figure 4A is an enlarged view showing the state in the process of composition between pin 20 and box 30 and showing the tip side of pin 20. In addition, the state in the process of composition means the state in which pin 20 is further threaded into box 30 from the state in which the composition begins, which is shown in Figure 2A. In the threaded connection 1 for a steel tube, as described above, in the state before pin 20 and box 30 are composed, pin 20 and box 30 satisfy the relation of the first condition (D1 <D3). Consequently, as shown in Figure 4A, the first portion R 26 of pin 20 does not come into contact with the third portion R 36 of box 30 and the first conical surface 22a and the third conical surface 32a smoothly come into contact with each other.
[00111] Figure 4B is an enlarged view showing the state in which the composition between pin 20 and box 30 is complete and shows the tip side of pin 20. As described below, in screw connection 1 for a steel tube, the support surface 24 of pin 20 and the support surface 34 of box 30 come into contiguous contact with each other and, therefore, the composition between pin 20 and box 30 is complete (see Figure 5B ). As shown in Figure 4B, in the state in which the composition between pin 20 and box 30 is complete, a part or all of the first sealing portion 22 comes in close contact with the third conical surface 32a throughout the circumference. At that time, there is a gap between the tip surface 25 of the pin 20 and the base surface 35 of the box 30.
[00112] Furthermore, in the state in which the composition is complete, since the first seal portion 22 and the third seal portion 32 interfere with each other in the radial direction, diameters D1 and D3 in the state before the composition do not necessarily coincide with diameters D1 'and D3' in the state in which the composition is complete.
[00113] Furthermore, in Figure 4B, the first tapered surface 22a and the third tapered surface 32a come into contact with each other. However, at least one of the first curvature surface 22b and the first tapered surface 22a can come into contact with the third tapered surface 32a.
[00114] Figure 5A is an enlarged view showing the state of the composition process between pin 20 and box 30 and showing the base side of pin 20. In addition, Figure 5A corresponds to Figure 4A. As described above, in the state before pin 20 and box 30 are composed, pin 20 and box 30 satisfy the relationship of the second condition (D2 <D4). Consequently, as shown in Figure 5A, the second portion R 27 of the pin 20 does not come into contact with the fourth portion R 37 of the box 30 and the second conical surface 23a and the fourth conical surface 33a smoothly come into contact with each other.
[00115] Figure 5B is an enlarged view showing the state in which the composition between pin 20 and box 30 is complete and shows the base side of pin 20. In addition, Figure 5B is a view that matches responds to Figure 4B. As shown in Figure 5B, in the state in which the composition is complete, part or all of the fourth sealing portion 33 comes in close contact with the second conical surface 23a throughout the circumference. In addition, in the threaded connection 1 for a steel tube, the support surface 24 of pin 20 and the support surface 34 of box 30 come into contiguous contact with each other and therefore the composition between pin 20 and box 30 is completed.
[00116] Additionally, in the state in which the composition is complete, since the second sealing portion 23 and the fourth sealing portion 33 interfere with each other in the radial direction, diameters D2 and D4 in the previous state to the composition do not necessarily coincide with diameters D2 'and D4' in the state in which the composition is complete.
[00117] Furthermore, in Figure 5B, the second conical surface 23a and the fourth conical surface 33a come into contact with each other. However, at least one of the fourth conical surface 33a and the second curvature surface 33b can come in contact with the second conical surface 23a.
[00118] Additionally, as described above, when pin 20 and box 30 are composed, it is possible to use a compositing device called the power tongue.
[00119] As described above, in the threaded connection 1 for a steel tube 1 according to the first modality, portions R 26 and 27 of pin 20 do not come into contact with portions R 36 and 37 of box 30, respectively. As a result, in the process in which pin 20 is threaded into box 30, the tube geometric axis (center) of pin 20 and the tube geometric axis (center) of box 30 align with each other and therefore , threading is smoothly performed. In this way, it is possible to prevent the prominence of the compounding torque.
[00120] In addition, when the R 26 and 27 portions of pin 20 come into contact with the R 36 and 37 portions of box 30, since the curvature surfaces come into contact with each other, the contact area is decreased. In this case, a high contact pressure is generated in the regions in which the R 26 and 27 portions of pin 20 and the R 36 and 37 portions of box 30 come into contact with each other and, therefore, wear easily occurs. However, on screw connection 1, contacts between the R 26 and 27 portions of pin 20 and the R 36 and 37 portions of box 30 can be avoided and, as a result, wear can be prevented. Thus, in the screw connection 1, there is an advantage that wear does not occur easily.
[00121] Any integral type or coupling type can be applied to threaded connection 1 according to the first modality. In the case of the integral type, both the upper tube 2 and the lower tube 3 are steel tubes. In the case of the coupling type, the upper tube 2 is a steel tube and the lower tube 3 is a coupling (short tube).
[00122] Furthermore, since the prominence of the compounding torque easily occurs when steel tubes that have large diameters are connected to each other, preferably the screw connection 1 according to the first modality is used to connect steel tubes that have large diameters. For example, in the case of integral type, preferably, the external diameters of the main bodies (portions except for the pin and housing) of the upper tube 2 (steel tube) and the lower tube 3 (steel tube) are equal to or greater than 190 mm, more preferably equal to or greater than 240 mm and, more preferably still, equal to or greater than 290 mm.
[00123] Furthermore, the prominence of the composition torque easily occurs as the thickness of the box 30 is reduced. For example, in the state before the composition begins, when the outer diameter of the box 30 of the lower tube 3 is greater than 100% and less than 104% in relation to the outer diameter of the body (the portion except for the pin 20 in the upper tube 2) of the upper tube 2, the predominance of the composition torque easily occurs. Thus, when the outer diameter of the box 30 of the lower tube 3 is greater than 100% and less than 104% in relation to the outer diameter of the body of the upper tube 2, the effects of suppression in relation to the prominence are increased through the screw connection 1.
[00124] The upper limit of the outside diameter of each of the main bodies (the portion except for pin 20 on the upper pipe 2 and the portion except for the box 30 on the lower pipe 3) of the upper pipe 2 and the lower pipe 3 it is not particularly limited. However, in a case where it is used in oil well tubes, a metal seal is not used in close proximity in a threaded connection for an oil well tube that has a super large diameter (more than 600 mm) such as a conductor that is buried by shallow depth. In view of this, the screw connection 1 can be used appropriately in a steel tube in which the outer diameter of the body is less than or equal to 600 mm.
[00125] Also in the coupling type, similarly, preferably, the outer diameter of the upper tube 2 body (steel tube) is equal to or greater than 190 mm, more preferably, equal to or greater than 240 mm and , even more preferably, equal to or greater than 290 mm.
[00126] Here, in general, the dimension accuracy of the steel tube can be decreased as the size (diameter, length and the like) of the steel tube is increased. In the case of steel tubes that have large diameters, in the state before pin 20 and box 30 are composed, the decrease in dimension accuracy influences the rounding in the sealing portions (conical surface) of pin 20 and box 30 Thus, when the threaded connection 1 according to the first modality is used to connect steel tubes that have large diameters, taking into account the rounding of each sealing portion (each conical surface), preferably the diameters D1 and D2 of pin 20 and diameters D3 and D4 of box 30 in the state before pin 20 and box 30 are composed are designed appropriately.
[00127] Specifically, when the differences between the diameters D1 and D2 of pin 20 in the pre-composition state and the diameters D3 and D4 of box 30 in the pre-composition state are small, the effects of preventing prominence cannot be sufficiently achieved when rounding is extremely decreased. In addition, when surface treatment such as chemical conversion or plating treatments are carried out on pin 20 or box 30, the effect of preventing prominence cannot be sufficiently achieved if the difference between diameter D1 and diameter D3 and the difference between diameter D2 and diameter D4 are not provided equal to or greater than the thickness of the surface treatment. Additionally, when the contact between the conical surfaces begins, since there are many gaps between the male thread portion 21 and the female thread portion 31, it is possible to increase the effect of preventing prominence if a margin in the difference of diameter is provided.
[00128] Meanwhile, if the differences between the diameters D1 and D2 of pin 20 in the state prior to the composition and the diameters D3 and D4 of box 30 in the state prior to the composition are configured greater than required, it is necessary to increase the length of the tapered surface of the sealing portion and therefore the manufacturing cost is increased due to the expensive design.
[00129] According to the above, preferably, the difference between diameter D1 and diameter D3 and the difference between diameter D2 and diameter D4 are greater than 0% and less than or equal to 0.3% the outer diameter of the steel tube body (upper tube 2) and, more preferably, greater than 0.05% and less than or equal to 0.2%.
[00130] The first mode shows the case where the sealing portions (first sealing portion 22 and second sealing portion 23) are provided on the tip side and on the base side of pin 20 and the sealing portions ( third sealing portions 32 and fourth sealing portion 33) corresponding to it are provided in box 30. However, according to the sealing performance and pressure resistance required in the screw connection 1 for a steel pipe, the The sealing portion can be provided on both the front (tip side) and the rear (base side) of the region in which the tapered thread (male thread portion 21 or female thread portion 31) is formed. That is, only one of the first sealing portion 22 and the second sealing portion 23 can be provided and, accordingly, the third sealing portion 32 or the fourth sealing portion 33 can be provided in the box 30 .
[00131] Additionally, the first modality shows the case where the support surface 24 of pin 20 is provided at the base (the rear end of pin 20) of pin 20 and, accordingly, the surface of bracket 34 of box 30 is provided at the tip (the front end of box 30) of box 30. However, in consideration of the sealing and pressure resistance performance required in threaded connection 1 for a steel pipe, as shown in 6, the support surface 25a can be provided on the tip surface 25 of the pin 20 and accordingly, the support surface 35a can be provided on the base surface of the box 30. SECOND MODE
[00132] Next, a threaded connection 100 for a steel tube according to a second embodiment of the present invention will be described. In addition, the same reference numerals are assigned to the same components as the components described above and their descriptions are omitted below.
[00133] Figure 7 is a longitudinal sectional view showing the threaded connection 100 for a steel tube according to the second modality. In the first modality, only one region of the tapered thread is formed. In the embodiment, as shown in Figure 7, the male thread portion 21 of pin 20 is divided into two along the direction of the pipe axis and an upper portion of male thread 128 and a lower portion of male thread 129 are formed. Similarly, the female thread portion 31 of the housing 30 is divided into two along the direction of the pipe axis and an upper female thread portion 138 and a lower female thread portion 139 are formed. A fifth seal portion 121 is provided in one portion (in an intermediate portion) between the upper portion of male thread 128 and the lower portion of male thread 129 and a sixth portion of seal 131 is provided in a portion between the upper portion upper female thread 138 and lower female thread 139. In addition, the fifth seal portion 121 and the sixth seal portion 131 are configured from a fifth tapered surface 121a and a sixth tapered surface 131a, respectively .
[00134] Compared to the first modality, in the threaded connection 100 for a steel tube according to the second mode, since the fifth sealing portion 121 and the sixth sealing portion 131 serve as reinforcement seals even when leaking occurs in any of the first sealing portion 22, the second sealing portion 23, the third sealing portion 32 and the fourth sealing portion 33, it is possible to further improve the sealing performance and pressure resistance.
[00135] Additionally, in the screw connection 100 according to the second embodiment, the male threaded connection 21 of pin 20 can be divided into three or more and the female threaded portion 31 of box 30 can be divided into three or more. In that case, a sealing portion can be provided between the divided male thread portions 21 and, accordingly, a sealing portion can be provided between the divided female thread portions 31.
[00136] In the above, the modalities of the present invention are described. However, the modalities are presented as examples and the scope of the present invention is not limited to the modalities. In the modalities, several aspects can be carried out and several examples of omissions, substitutions and modifications can be carried out within a scope that does not deviate from the essence of the invention. If the modifications or examples of modification are included in the claims or in the essence of the invention, the modifications or examples of modification are included in the scope equivalent to the inventions described in the claims.
[00137] For example, a threaded connection in which the upper tube 2 (first tube) includes the box 30 and the lower tube 3 (second tube) includes the pin 20 can be adopted. EXAMPLE
[00138] In order to confirm the effects of the present invention, a steel tube in which integral type screw connections shown in Table 1 and Table 2 were configured was manufactured and a test regarding the composition between a pin and a box was performed using a compositing device. Characteristics in relation to a material and dimensions of the steel tube are shown in Table 1. TABLE 1


[00139] A dimension relationship between the diameter D1 of the front end on the first tapered surface of the pin and the diameter D3 of the front end on the third tapered surface of the box and a dimension relationship between the diameter D2 of the front end on second conical surface of the pin and the diameter D4 of the front end on the fourth conical surface of the box are shown in Table 2. TABLE 2

[00140] In the Example, in both the first sealing portion and the second sealing portion of the pin, since the diameters D1 and D2 of the front ends on the conical surfaces of the pin were smaller than the diameters D3 and D4 of the ends fronts on the conical surfaces of the box, respectively, as shown in Figure 8, the prominence of the composition torque did not occur. In the Comparative Example, both in the first sealing portion and in the second sealing portion of the pin, since the diameters D1 and D2 of the front ends on the conical surfaces of the pin were larger than the diameters D3 and D4 of the front ends on the surfaces taper of the box, respectively, as shown in Figure 10, the prominence of the composition torque occurred. INDUSTRIAL APPLICABILITY
[00141] According to the present invention, it is possible to provide a threaded connection for a steel tube that has the ability to prevent the prominence of a torque of composition that occurred when a pin and a box are composed. BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS 1: threaded connection for steel pipe (first mode) 2: upper pipe (first pipe) 3: lower pipe (second pipe) 20: pin 21: male thread portion 22: first sealing portion ( pin sealing portion) 22a: first tapered surface (tapered surface of first sealing portion) 22b: first bending surface (bending surface of first sealing portion) 22c: front end of first tapered surface 22d: rear end of the first tapered surface 23: second sealing portion (pin sealing portion) 23a: second tapered surface (tapered surface of the second sealing portion) 23b: front end of the second tapered surface 23c: rear end of the second tapered surface 24: surface pin support (pin base surface) 25: pin tip surface 26: first R portion (front R portion of pin) 27: second R portion (rear R portion of pin) 30: box 31: female thread portion 32: third sealing portion (housing seal portion) 32a: third tapered surface (tapered surface of third sealing portion) 32b: front end of the third tapered surface 32c: rear end of the third tapered surface 33 : fourth sealing portion (box sealing portion) 33a: fourth conical surface (conical surface of fourth sealing portion) 33b: second curvature surface (curvature surface of fourth sealing portion) 33c: front end of the fourth tapered surface 33d: rear end of the fourth tapered surface 34: box support surface (box tip surface) 35: box base surface 36: third portion R (rear portion of box) 37: fourth portion R (portion Box front R) 100: threaded connection for steel pipe (second mode) 121: fifth sealing portion (pin sealing portion) 121a: fifth conical surface (conical surface of fifth portion d and seal) 128: upper male thread portion 129: lower male thread portion 131: sixth sealing portion (housing seal portion) 131a: sixth tapered surface (sixth sealing portion tapered surface) 138: female threaded portion upper 139: lower female thread portion D1: front end diameter of first tapered surface (minimum diameter of first tapered surface) D2: front end diameter of second tapered surface (minimum diameter of second tapered surface) D3: front end diameter of third conical surface (maximum diameter of third conical surface) D4: front end diameter of fourth conical surface (maximum diameter of fourth conical surface) CL: tube geometric axis Pin: internal pressure Pout: external pressure
权利要求:
Claims (11)
[0001]
1. Threaded connection (1) for a steel pipe that connects a first pipe (2) and a second pipe (3), the threaded connection (1) being characterized by the fact that it comprises: a box (30 ) which is an opening end of the second tube (3); and a pin (20) in the shape of a truncated cone which is an end of the first tube (2) and is inserted in the box (30), the pin (20) including a male thread portion (21) which is a tapered thread and a sealing portion (22, 23) which includes a tapered surface and the housing (30) includes a female threaded portion (31) which is a tapered thread and a sealing portion (32, 33) which includes a tapered surface and the pin (20) and the box (30) are configured so that when the male thread portion (21) and the female thread portion (31) are composed by threading, a root ( 21d) of the male threaded portion (21) and a ridge (31c) of the female threaded portion (31) come into contact with each other after the sealing portion (22, 23) of the pin (20) and the seal (32, 33) of the housing (30) come into contact with each other, in a composition process and in a state prior to the composition, a minimum diameter of the tapered surface of the pin (20) is less than a maximum diameter of the surface conic of the falls x (30).
[0002]
2. Threaded connection (1) for a steel tube, according to claim 1, characterized by the fact that the sealing portion of the pin (20) is provided on each side of the tip of the pin (20). - male thread (21) and on a base side of the pin (20) of the male thread portion (21).
[0003]
3. Threaded connection (1) for a steel tube, according to claim 1 or 2, characterized in that the pin (20) further includes a portion R which is provided on one end of the pin (20) of the sealing portion (22) of the pin (20) and the housing (30) additionally includes a portion R which is provided on one end side of the housing (30) of the sealing portion (33) of the housing (30) .
[0004]
Threaded connection (1) for a steel pipe according to any one of claims 1 to 3, characterized in that the male thread portion is divided into a plurality of male thread portions (128, 129) along along a pipe axis axis direction of the first pipe (2), and the sealing portion (121) of the pin (20) is further provided between the male thread portions (128, 129) adjacent to each other in the axis direction geometric pattern.
[0005]
5. Threaded connection (1) for a steel tube, according to any one of claims 1 to 4, characterized in that the pin (20) also includes a support surface (24, 25) which is provided in a tip or base of the pin (20).
[0006]
6. Threaded connection (1) for a steel tube according to any one of claims 1 to 5, characterized by the fact that each of the first tube (2) and the second tube (3) is a steel tube .
[0007]
7. Threaded connection (1) for a steel tube, according to claim 6, characterized by the fact that an outer diameter of a body of the first tube (2) is 190 mm or more, an outer diameter of a body of the second tube (3) is 190 mm or more and in the pre-composition state, an outer diameter of the box (30) is more than 100% of the outer diameter of the body of the first tube (2), and is less than 104% of the outer diameter of the body of the first tube (2).
[0008]
8. Threaded connection (1) for a steel tube, according to claim 7, characterized by the fact that in the state prior to the composition, a difference between the minimum diameter of the tapered surface of the pin (20) and the diameter The maximum conical surface of the box (30) is more than 0% of the outer diameter of the body of the first tube (2), and is 0.3% or less of the outer diameter of the body of the first tube (2).
[0009]
9. Threaded connection (1) for a steel tube according to any one of claims 1 to 5, characterized in that the first tube (2) is a steel tube, and the second tube (3) is a coupling.
[0010]
10. Threaded connection (1) for a steel tube, according to claim 9, characterized by the fact that an outside diameter of a body of the first tube (2) is 190 mm or more.
[0011]
11. Threaded connection (1) for a steel tube, according to claim 10, characterized by the fact that in the state prior to the composition, a difference between the minimum diameter of the tapered surface of the pin (20) and the diameter The maximum conical surface of the box (30) is more than 0% of the outer diameter of the body of the first tube (2) and is 0.3% or less of the outer diameter of the body of the first tube (2).
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BR112018013662B1|2021-11-16|THREADED JOINT FOR STEEL TUBE
JP6891855B2|2021-06-18|Threaded joints for oil country tubular goods
BR112018016593B1|2021-10-26|THREADED JOINT FOR OIL WELL PIPING
同族专利:
公开号 | 公开日
RU2642922C2|2018-01-29|
RU2016107380A|2017-10-11|
JP6220880B2|2017-10-25|
US20160208962A1|2016-07-21|
MX2016002809A|2016-06-22|
US20220065371A1|2022-03-03|
EP3043098A1|2016-07-13|
CN105518364A|2016-04-20|
CN105518364B|2018-07-17|
EP3043098A4|2017-05-10|
WO2015033997A1|2015-03-12|
CA2921411C|2018-07-10|
CA2921411A1|2015-03-12|
JPWO2015033997A1|2017-03-02|
引用文献:
公开号 | 申请日 | 公开日 | 申请人 | 专利标题

US4521042A|1983-07-05|1985-06-04|Hydril Company|Threaded connection|
FR2571467B1|1984-10-10|1987-03-20|Vallourec|THREADED JOINT FOR A STEEL TUBE HAVING A THREADED SEALING DEVICE|
US5649725A|1994-10-19|1997-07-22|Sumitomo Metal Industries Limited|Thread joint for tube|
JP2877010B2|1994-11-04|1999-03-31|住友金属工業株式会社|Threaded fittings for oil country tubular goods|
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CA2739711C|2008-10-20|2013-08-20|Sumitomo Metal Industries, Ltd.|Threaded joint for steel pipes with specific sealing surface|
FR2952993B1|2009-11-20|2011-12-16|Vallourec Mannesmann Oil & Gas|THREADED JOINT|
JP4930647B1|2010-06-30|2012-05-16|Jfeスチール株式会社|Threaded joints for pipes|
JP5665653B2|2011-05-23|2015-02-04|エヌケーケーシームレス鋼管株式会社|Double shoulder type tool joint|US10240403B2|2013-12-06|2019-03-26|Schlumberger Technology Corporation|Opposing thread screw safety joint|
RU2659834C1|2014-10-06|2018-07-04|Ниппон Стил Энд Сумитомо Метал Корпорейшн|Threaded connection for steel pipes|
JP6578810B2|2015-08-19|2019-09-25|日本製鉄株式会社|Oil well pipe|
US11047413B2|2016-04-27|2021-06-29|Hydril Company|Threaded and coupled tubular goods connection|
KR101808705B1|2016-05-16|2017-12-15|주식회사유한훌로텍|Structure for preventing leak of synthetic resin tube joint|
US20190093799A1|2016-06-08|2019-03-28|Nippon Steel & Sumitomo Metal Corporation|Threaded Connection for Steel Pipe|
EP3260649B1|2016-06-21|2019-12-18|Energy Frontier Solutions S.L.|Threaded joint for oil and gas pipes|
WO2018011906A1|2016-07-13|2018-01-18|井上スダレ株式会社|Pipe joint|
EP3473798B1|2017-10-20|2020-03-11|Vallourec Oil And Gas France|Threaded connection partially in a self-locking engagement|
RU185638U1|2018-08-20|2018-12-13|Общество с ограниченной ответственностью Завод "Авеко Тьюб"|SEALED THREADED CONNECTION|
CA3115198A1|2018-10-11|2020-04-16|Nippon Steel Corporation|Threaded connection for steel pipe|
NL2025828B1|2020-06-15|2022-02-16|Tenaris Connections Bv|Threaded connection for hammering interconnected tubular members|
法律状态:
2019-09-10| B25D| Requested change of name of applicant approved|Owner name: VALLOUREC OIL AND GAS FRANCE (FR) ; NIPPON STEEL C |
2020-11-03| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
2020-12-29| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 04/09/2014, OBSERVADAS AS CONDICOES LEGAIS. |
优先权:
申请号 | 申请日 | 专利标题
JP2013-184717|2013-09-06|
JP2013184717|2013-09-06|
PCT/JP2014/073318|WO2015033997A1|2013-09-06|2014-09-04|Threaded coupling for steel pipe|
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