JP2001124254A - Steel pipe, and its threading method - Google Patents
Steel pipe, and its threading methodInfo
- Publication number
- JP2001124254A JP2001124254A JP29958799A JP29958799A JP2001124254A JP 2001124254 A JP2001124254 A JP 2001124254A JP 29958799 A JP29958799 A JP 29958799A JP 29958799 A JP29958799 A JP 29958799A JP 2001124254 A JP2001124254 A JP 2001124254A
- Authority
- JP
- Japan
- Prior art keywords
- steel pipe
- machining
- thread
- incomplete
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、例えば油井管やガ
ス井管等の鋼管およびそのねじ切り方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe such as an oil well pipe and a gas well pipe and a method for threading the same.
【０００２】[0002]
【従来の技術】例えば油井や天然ガス井等（以下、単に
「油井」という。）の使用環境は、年々厳しくなってお
り、油井に用いられる油井管やガス井管等の鋼管を相互
に連結するためのねじ継手には、強大な軸力に耐え、か
つ高い気密性を有することが、ともに要求される。この
ねじ継手には様々な種類がある。図７および図８は、い
ずれも、この種のねじ継手の一例を部分的に示す説明図
である。2. Description of the Related Art The use environment of oil wells and natural gas wells (hereinafter simply referred to as "oil wells") has become severer year by year, and steel pipes such as oil well pipes and gas well pipes used in oil wells are interconnected. It is required that the threaded joint to withstand a strong axial force and have high airtightness. There are various types of this threaded joint. 7 and 8 are explanatory views partially showing an example of this type of threaded joint.
【０００３】図７に示すねじ継手は、ＡＰＩ（米国石油
協会）規格のＳＴＤ５Ｂに規定された台形ねじを有する
バットレス継手１である。同図に示すように、バットレ
ス継手１は、鋼管２の先端にテーパ雄ねじ３および不完
全ねじ部４を有するピン部５と、カップリング６の両端
内部に設けられたテーパ雌ねじ部７を有するボックス部
８とからなる。テーパ雄ねじ３は、外削加工を行われた
平滑な外削面に形成される。The threaded joint shown in FIG. 7 is a buttressed joint 1 having a trapezoidal thread specified in STD5B of API (American Petroleum Institute) standard. As shown in the figure, a buttress joint 1 has a box having a pin portion 5 having a tapered male screw 3 and an incomplete thread portion 4 at the tip of a steel pipe 2 and a tapered female screw portion 7 provided inside both ends of a coupling 6. 8. The tapered male screw 3 is formed on a smooth externally machined surface that has been subjected to external machining.
【０００４】また、図８に示すねじ継手は、いわゆる特
殊継手９である。この特殊継手９は、鋼管10の先端にテ
ーパ雄ねじ11および不完全ねじ部12を有するピン部13
と、カップリング14の両端内部に設けられたテーパ雌ね
じ部15を有するボックス部16とからなる。テーパ雄ねじ
11は、外削加工を行われた平滑な外削面に形成される。
さらに、ピン部13の先端にはトルクショルダ用ねじ無し
部17が形成されるとともに、ボックス部16の内奥にはト
ルクショルダ用ねじ無し部17が当接して過剰な締め付け
を防止する受け面18が形成される。また、トルクショル
ダ用ねじ無し部17に連続するメタルシール部19およびこ
れに当接するボックスメタルシール部20によりメタルタ
ッチのシール面が形成され、これにより気密性が高めら
れる。A threaded joint shown in FIG. 8 is a so-called special joint 9. This special joint 9 has a pin 13 having a tapered male screw 11 and an incomplete thread 12 at the tip of a steel pipe 10.
And a box portion 16 having a tapered female screw portion 15 provided inside both ends of the coupling 14. Male taper thread
Numeral 11 is formed on a smooth externally machined surface after external machining.
Furthermore, a torque shoulder screwless portion 17 is formed at the tip of the pin portion 13, and a torque shoulder screwless portion 17 abuts on the inner side of the box portion 16 to prevent excessive tightening. Is formed. In addition, a metal touch seal surface is formed by the metal seal portion 19 continuous with the torque shoulder screwless portion 17 and the box metal seal portion 20 abutting on the metal seal portion 19, thereby improving airtightness.
【０００５】[0005]
【発明が解決しようとする課題】しかし、これらの従来
のねじ継手１、９には、以下に列記する課題１および課
題２がある。 (課題１)図７に示すバットレス継手１のピン部５におけ
る不完全ねじ部４や、図８に示す特殊継手９のピン部13
における不完全ねじ部12に設けられたねじ山には、ねじ
切りに伴って、かえりが発生する。However, these conventional threaded joints 1 and 9 have problems 1 and 2 listed below. (Problem 1) The imperfect thread portion 4 in the pin portion 5 of the buttress joint 1 shown in FIG. 7 and the pin portion 13 of the special joint 9 shown in FIG.
In the thread provided in the incomplete threaded portion 12 in the above, burrs are generated along with the thread cutting.
【０００６】図９(a) は、かえり4b(12b) が発生したね
じ山4a(12a) を示す説明図であり、図10(a) はかえり4b
(12b) がテーパ雌ねじ部７(15)と干渉する状況を示す説
明図である。図９(a) に示すように、不完全ねじ部４(1
2)に設けられたねじ山4a(12a) にはかえり4b(12b) が発
生する。また、図７に示すバットレス継手１のピン部５
や、図８に示す特殊継手９のピン部13には、いずれも、
テーパ雄ねじ３、11が形成されている。このため、かえ
り4b(12b) が発生した不完全ねじ部４(12)のねじ山径
は、管外径を超えてしまう。発生したかえり4b(12b)
は、図10(a) に示すように、特に、海上油田等の鋼管
２、10が安定しない状況での使用中にテーパ雌ねじ部７
(15)と接触、干渉するため、締付けトルクの異常な上昇
や、ねじ部の焼き付きを発生させてしまう。このため、
図９(a) に示すようにかえり4b(12b) が発生した場合に
は、バフ砥石等を用いてこのかえり4b(12b) を研削除去
する必要がある。図９(b) は、バフ砥石等を用いてかえ
り4b(12b) の研削除去が行われた後のねじ山4a(12a) を
示す説明図であり、図10(b) はかえり4b(12b) がテーパ
雌ねじ部７(15)と干渉する状況を示す説明図である。し
かし、この手段でも、図９(b) に示すように、かえり4b
(12b) が管長手方向へ倒れ込んでしまうため、図10(b)
に示すように、テーパ雌ねじ部７(15)との接触、干渉が
かえって強まってしまう。また、不完全ねじ部４、12の
ねじ切りの際、鋼管２、10のこのねじ切り部は外削加工
を行われていないために真円ではなく、周長方向への切
削負荷が不均一となる。このため、径方向へのかえり4
b、12b の大きさが不均一となり、バフ砥石等を用いて
もかえり4b、12b を完全に除去することは困難であっ
た。FIG. 9A is an explanatory view showing a thread 4a (12a) in which a burr 4b (12b) is generated. FIG. 10 (a) is a diagram showing the burr 4b (12b).
FIG. 12B is an explanatory view showing a situation in which (12b) interferes with the tapered female screw portion 7 (15). As shown in FIG. 9 (a), the incomplete thread 4 (1
A burr 4b (12b) is generated on the thread 4a (12a) provided in 2). Also, the pin portion 5 of the buttress joint 1 shown in FIG.
Also, in the pin portion 13 of the special joint 9 shown in FIG.
Tapered male screws 3 and 11 are formed. For this reason, the thread diameter of the incomplete thread portion 4 (12) where the burr 4b (12b) has occurred exceeds the outer diameter of the tube. Returned burr 4b (12b)
As shown in FIG. 10 (a), the tapered female thread portion 7 is used particularly when the steel pipes 2 and 10 are not stable in an offshore oil field or the like.
(15) may cause an abnormal increase in the tightening torque and seizure of the thread. For this reason,
When the burr 4b (12b) is generated as shown in FIG. 9A, it is necessary to grind and remove the burr 4b (12b) using a buffing stone or the like. FIG. 9 (b) is an explanatory view showing the thread 4a (12a) after the burr 4b (12b) has been ground and removed using a buffing wheel or the like, and FIG. 10 (b) shows the burr 4b (12b). FIG. 9 is an explanatory view showing a situation where the) interferes with the tapered female screw portion 7 (15). However, even with this means, as shown in FIG.
Because (12b) falls down in the longitudinal direction of the pipe,
As shown in (5), the contact and interference with the tapered female screw portion 7 (15) are rather strengthened. Further, when the incompletely threaded portions 4 and 12 are threaded, since the threaded portions of the steel pipes 2 and 10 are not subjected to external machining, they are not perfect circles and the cutting load in the circumferential direction becomes uneven. . Therefore, the burr in the radial direction 4
Since the sizes of b and 12b were not uniform, it was difficult to completely remove the burrs 4b and 12b even using a buffing stone or the like.
【０００７】従来のねじ継手１、９では、このように、
かえり4b、12b とテーパ雌ねじ部７、15との接触・干渉
を完全に防止することは不可能であったため、締め付け
トルクのハンピング (波打ち) が発生する。In the conventional threaded joints 1 and 9,
Since it was not possible to completely prevent contact and interference between the burrs 4b and 12b and the tapered female threads 7 and 15, a humping of the tightening torque occurs.
【０００８】図11は、ねじ山にかえり4b、12b が発生し
た不完全ねじ部４、12を有する継手について、発生トル
ク (締め付けトルク) に及ぼす締め付け回数の影響を示
すグラフである。同図にグラフで示すように、不完全ね
じ部４、12にかえり4b、12bが発生すると、締付けトル
クのハンピング（波打ち状の増減現象）が発生し、締付
けトルクにばらつきが発生して不完全締め付けとなり、
ねじ部での焼き付きが発生することがあった。この焼き
付きは、ねじ継手性能を低下させるため、焼き付きの有
無を確認するために締め付けたねじ継手を一旦締め戻す
必要もあった。このため、かえりの発生に起因して、油
井での降管作業時間が長時間化していた。 (課題２)ねじ継手１、９のピン部５、13の加工は、ねじ
切り加工工具を回転させずに鋼管２、10を軸線上に回転
させるか、または鋼管２、10を回転させずにねじ切り加
工工具を回転させることのいずれかの手段により、行わ
れてきた。しかし、前者の鋼管２、10を回転させる手段
は、同時に加工を行うことができるねじ切り加工工具数
に制限があるために加工パス回数が増加し、かつ、管の
回転始動や停止等に多くの時間を必要とするため、後者
のねじ切り加工工具を回転させる手段が多用されるよう
になってきた。近年、これらの加工では、加工能率向上
を図るため、内面加工、外削加工およびシール部粗加工
をいずれも行う前加工機と、ねじ切り、外削加工および
シール部仕上げ加工をいずれも行う仕上げ加工機との２
台の加工機を用いて行われるようになってきた。この仕
上げ加工機には芯出しチャックが附帯して設けられてお
り、この芯出しチャックにより鋼管２、10の先端側の傾
斜部を掴持することにより、前加工機の回転軸と仕上げ
加工機との回転軸とを一致させている。しかし、前加工
機と仕上げ加工機との２台の加工機でねじ継手１、９の
ピン部５、13を加工すると、例えば、芯出しチャックと
加工される油井管との間にねじ切削の切粉等が噛み込ん
で管本体チャックが芯ずれした状態でチャックされてし
まうことがある。この場合、前加工機で加工した際の鋼
管の芯と、仕上げ加工機で加工した際の鋼管の芯とがず
れて配置されてしまう。また、これまで、芯ずれ精度を
管理する方法は存在せず、またその管理値も規定されて
いなかった。このため、この状態で加工された油井管継
手は、上述したテーパ雄ねじ部３、11や不完全ねじ部
４、12に対する加工が不十分になる可能性が高く、油井
で使用された場合に気密性能が確保されなくなって加工
不良率を増加させてしまう。また、何とか加工できたと
しても、シール部を有する管端肉厚が不均一になり、や
はり気密性能を低下させてしまう。FIG. 11 is a graph showing the influence of the number of tightening times on the generated torque (tightening torque) for a joint having incomplete thread portions 4 and 12 in which burrs 4b and 12b are formed on the thread. As shown in the graph, when the burr 4b, 12b is generated on the incomplete screw portions 4, 12, the tightening torque humps (wavy increase / decrease phenomenon), and the tightening torque varies, resulting in incomplete operation. Tightening,
In some cases, seizure occurred in the screw portion. Since this seizure lowers the performance of the screw joint, it is necessary to temporarily retighten the screw joint which has been tightened in order to confirm the presence or absence of seizure. For this reason, due to the occurrence of burrs, the downcoming work time in the oil well has been prolonged. (Problem 2) The pin portions 5 and 13 of the threaded joints 1 and 9 are machined by rotating the steel pipes 2 and 10 on the axis without rotating the threading tool or by threading without rotating the steel pipes 2 and 10. This has been done by any means of rotating the working tool. However, the former means for rotating the steel pipes 2, 10 increases the number of machining passes due to the limitation on the number of threading tools that can be machined at the same time. Due to the need for time, the latter means for rotating the threading tool has been frequently used. In recent years, in these processes, in order to improve machining efficiency, a pre-processing machine that performs all internal machining, external machining, and rough machining of seals, and a finish machining that performs all of thread cutting, external machining, and seal machining 2 with machine
It has come to be performed using one processing machine. The finishing machine is provided with a centering chuck attached thereto. The centering chuck grips the inclined portion on the distal end side of the steel pipes 2 and 10 so that the rotating shaft of the pre-processing machine and the finishing machine can be fixed. And the rotation axis. However, when the pin portions 5 and 13 of the threaded joints 1 and 9 are machined by two machining machines, a pre-machining machine and a finishing machine, for example, the thread cutting between the centering chuck and the oil country tubular good to be machined is performed. In some cases, chips may be bitten and chucked in a state where the pipe body chuck is misaligned. In this case, the core of the steel pipe processed by the pre-processing machine is displaced from the core of the steel pipe processed by the finishing processing machine. Until now, there has been no method for managing misalignment accuracy, and no management value has been defined. For this reason, the oil country tubular goods processed in this state are likely to have insufficient processing for the above-mentioned tapered external thread parts 3, 11 and incomplete thread parts 4, 12, and are airtight when used in an oil well. The performance is no longer ensured, and the processing failure rate increases. Further, even if somehow processing can be performed, the wall thickness of the pipe end having the seal portion becomes non-uniform, and the airtight performance is also lowered.
【０００９】このように、従来のねじ継手１、９のピン
部５、13の加工では、かえりの発生に起因して締付けト
ルクのハンピングが発生したり、前加工機と仕上げ加工
機との２台の加工機でねじ継手１、９のピン部５、13を
加工する場合の芯ずれに起因して気密不良が発生してし
まうという課題があった。As described above, in the conventional processing of the pin portions 5 and 13 of the threaded joints 1 and 9, humping of the tightening torque occurs due to the generation of burrs, or the two of the pre-processing machine and the finishing processing machine are used. When processing the pin portions 5 and 13 of the threaded joints 1 and 9 with a single processing machine, there is a problem that poor airtightness occurs due to misalignment.
【００１０】本発明の目的は、これらの課題を解決する
こと、具体的には、かえりの発生に起因した締め付けト
ルクのハンピング、ねじ部での焼き付きさらには油井で
の降管作業時間の長時間化をいずれも解決するととも
に、前加工機と仕上げ加工機との２台の加工機でピン部
を加工した場合の芯ずれ、加工不良率の低下さらには気
密不良の発生をいずれも解決することができる鋼管およ
びそのねじ切り方法を提供することである。An object of the present invention is to solve these problems, and more specifically, to hamper the tightening torque due to the occurrence of burrs, seize in a screw portion, and further increase the time required for downcoming work in an oil well. And to resolve any misalignment, reduction of defective processing rate and occurrence of poor airtightness when the pin part is processed by two processing machines, a pre-processing machine and a finishing processing machine. And a method of cutting the same.
【００１１】[0011]
【課題を解決するための手段】本発明者は、上記課題を
解決するために鋭意検討を重ねた結果、従来にはねじ切
り前における外削加工を一切行われていない不完全ねじ
部の形成範囲にも、ねじ切り前に外削加工を行って外削
加工部を形成し、この外削加工部にねじ切りを行って不
完全ねじ部を形成することにより、(i) 不完全ねじ部の
周長上におけるかえりの発生を均一化および最小化で
き、かえり取りを確実かつ容易に行うことができるこ
と、(ii)かえり取りを確実かつ容易に行うことができる
ため、油井使用時の締め付けトルクの異常な変化やねじ
部の焼き付きの発生を、いずれも防止できること、(ii
i) 不完全ねじ部の形成範囲には外削加工を行わない従
来の加工方法では、不完全ねじ部は、鋼管肌を呈してお
り不連続な凹凸がある。このため、ねじ切り時にねじ切
り加工工具の欠損が多発していた。しかし、ねじ切り前
に外削加工を行って外削加工部を形成することにより、
加工中のねじ切り加工工具に作用する負荷が安定し、工
具寿命が著しく向上すること、および(iv)前加工機と仕
上げ加工機との２台の加工機でねじ継手を加工する際
に、仕上げ加工機でのシール部加工取り代を一定量残し
て前加工機で加工した後、仕上げ加工機の芯出し時に
は、上記の外削加工部を利用して本体チャックを行うこ
とにより、本体チャックの芯ずれが仕上げ加工機でのシ
ール部加工取り代以上発生した場合には前加工不良と判
断して加工を中止することができ、テーパ雄ねじ部およ
び不完全ねじ部の未加工部を解消できることという極め
て有用な効果が奏されることを知見し、さらに検討を重
ねて本発明を完成した。ここに、本発明は、管端部外面
に、テーパ雄ねじ部に隣接する不完全ねじ部を備え、こ
の不完全ねじ部の少なくとも一部が、外削加工を行われ
た外削加工部に設けられることを特徴とする鋼管であ
る。この本発明にかかる鋼管では、外削加工部が、テー
パ雄ねじ部の形成領域における管外径の最大値と同じ値
で略一定である管外径を有するように、形成されること
が、望ましい。The inventor of the present invention has made intensive studies in order to solve the above-mentioned problems, and as a result, has found that the formation range of an incompletely threaded portion which has not conventionally been subjected to any external machining before thread cutting. In addition, by performing external machining before threading to form an externally machined part, and performing thread cutting on this externally machined part to form an incomplete threaded part, (i) the circumferential length of the incompletely threaded part Burrs can be uniformly and minimized, and burrs can be reliably and easily performed. (Ii) Since burrs can be performed reliably and easily, abnormal tightening torque when using an oil well is considered. Change and seizure of the thread can be prevented, (ii
i) In the conventional processing method in which external machining is not performed in the formation range of the incomplete thread portion, the incomplete thread portion has a steel pipe skin and has discontinuous irregularities. For this reason, there has been a large number of defects in the threading tool during threading. However, by performing external machining before threading to form an external machining part,
The load acting on the threading tool during machining is stable and the tool life is significantly improved. (Iv) When machining threaded joints with two machines, a pre-machining machine and a finishing machine, After processing with the pre-processing machine while leaving a certain amount of seal part machining allowance in the processing machine, when centering the finish processing machine, the main body chuck is performed by using the external machining part described above, If the misalignment occurs more than the machining allowance of the seal part in the finishing machine, it can be judged that the pre-processing is defective and the processing can be stopped, and the unprocessed part of the tapered male thread and incomplete thread can be eliminated. The inventors have found that a very useful effect is achieved, and have further studied and completed the present invention. Here, the present invention includes, on the outer surface of the pipe end, an incomplete thread portion adjacent to the tapered external thread portion, and at least a part of the incomplete thread portion is provided in the externally machined portion subjected to the external machining. It is a steel pipe characterized by being made. In the steel pipe according to the present invention, it is preferable that the externally machined portion is formed so as to have a pipe outer diameter that is substantially constant at the same value as the maximum value of the pipe outer diameter in the formation region of the tapered male screw portion. .
【００１２】別の観点からは、本発明は、鋼管の管端面
から管軸方向へ向けて外削加工を行うことにより外削加
工部を設けた後に、この外削加工部に、テーパ雄ねじ部
に隣接する不完全ねじ部の少なくとも一部を設けること
を特徴とする鋼管のねじ切り方法である。この本発明に
かかる鋼管のねじ切り方法では、外削加工部が、テーパ
雄ねじ部の形成領域における管外径の最大値と同じ値で
略一定である管外径を有するように、形成されること
が、望ましい。From another viewpoint, the present invention provides an external machining portion by performing external machining from the pipe end face in the axial direction of the steel pipe, and then providing the externally machined portion with a tapered male screw portion. A method for cutting a steel pipe, characterized in that at least a part of an incompletely threaded portion adjacent to the pipe is provided. In the thread cutting method for a steel pipe according to the present invention, the externally machined portion is formed so as to have a pipe outer diameter which is substantially constant at the same value as the maximum value of the pipe outer diameter in the formation region of the tapered external thread portion. But desirable.
【００１３】[0013]
【発明の実施の形態】以下、本発明にかかる鋼管および
そのねじ切り方法の実施の形態を、添付図面を参照しな
がら詳細に説明する。なお、以降の説明では、鋼管が油
井管であり、継手がバットレス継手であるとともに、ね
じ切り加工工具を回転させてねじ切りを行う場合を例に
とる。 〔鋼管21〕図１(a) は、本実施形態の鋼管21の不完全ね
じ部22を拡大して示す説明図であり、図１(b) は、従来
の不完全ねじ部22' の噛み合いを示す説明図であり、図
１(c) は、本実施形態の不完全ねじ部22の噛み合いを示
す説明図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a steel pipe and a thread cutting method according to the present invention will be described in detail with reference to the accompanying drawings. In the following description, an example is given in which the steel pipe is an oil country tubular good, the joint is a buttress joint, and the thread cutting tool is rotated to perform thread cutting. [Steel Pipe 21] FIG. 1 (a) is an enlarged view showing an incompletely threaded portion 22 of the steel pipe 21 of the present embodiment, and FIG. FIG. 1 (c) is an explanatory diagram showing the engagement of the incomplete screw portion 22 of the present embodiment.
【００１４】図１(a) に示すように、本実施形態の鋼管
21は、外径がd0であって、管端部外面に、テーパ雄ねじ
部23と、テーパ雄ねじ部23に隣接する不完全ねじ部22と
を備える。As shown in FIG. 1A, the steel pipe of the present embodiment
21 has an outer diameter a d 0, the pipe end outer surface includes a tapered male threaded portion 23, and a incomplete thread portion 22 adjacent to the tapered male screw portion 23.
【００１５】本実施形態におけるテーパ雄ねじ部23は、
公知のバットレス継手のテーパ雄ねじ部と同じであるた
め、説明を省略する。不完全ねじ部22は、管端部外面
に、管軸方向についてテーパ雄ねじ部23に隣接して形成
される。この不完全ねじ部22の少なくとも一部は、外削
加工を行われた外削加工部24に形成される。すなわち、
従来は、テーパ雄ねじ部23の形成範囲だけ外削加工が行
われ、不完全ねじ部22の形成範囲には外削加工は行われ
ていなかった。これに対して、本実施形態の鋼管21で
は、テーパ雄ねじ部23の形成範囲だけでなく不完全ねじ
部22の形成範囲にも外削加工が行われている。また、こ
の本実施形態における外削加工部24は、テーパ雄ねじ部
23の形成領域における管外径の最大値d2と同じ値で略一
定である管外径d3を有するように、形成される。外削加
工部24は、テーパ雄ねじ部23および不完全ねじ部22を形
成する前に、外削加工を行われることにより、形成され
る。また、図１(a) に示すように、本実施形態では、不
完全ねじ部22の全域ではなく、ねじ切り上がり部25の２
山手前まで外削加工を行ってある。これにより、ピン部
およびボックス部それぞれのねじ山噛み合いの最終位置
を、従来のバットレス継手のねじ山噛み合いの最終位置
と同じにすること、すなわち継手強度≧管本体強度とす
ることができ、継手の引張性能を低下させない。ねじ切
り上がり部25の２山手前までの部分は、継手締め付けの
最終段階で、ボックスねじ部と接触するため、ピン部お
よびボックス部それぞれの一直線性が確保される。した
がって、締め付け状態への影響が小さくなり、締め付け
トルクの異常な変化やねじ部焼き付きを発生させない。
また、この本実施形態のバットレス継手を油井で締め付
ける際、鋼管21が傾斜配置されると、図１(b) に示す従
来の不完全ねじ部22' はテーパ雌ねじ部７に干渉するの
に対して、図１(c) に示す本実施形態の不完全ねじ部22
は、外削加工量d1 (＝d0−d2)1だけねじ山の高さ、すな
わちかえりの高さが低減されるため、不完全ねじ部22は
テーパ雌ねじ部７に干渉しなくなる。 〔鋼管21のねじ切り方法〕次に、本実施形態のこの鋼管
21のねじ切り方法を説明する。図２は、本実施形態にお
いて、内削工具26および外削工具27を有する前加工機28
により、鋼管21に内面加工、外削加工およびシール部粗
加工をいずれも行う状況を模式的に示す説明図である。
また、図３は、本実施形態において、ねじ切り加工工具
29およびシール加工工具30を有する仕上げ加工機31によ
り、前加工機28による前加工を行われた鋼管21に、ねじ
切り加工、外削加工およびシール部仕上げ加工をいずれ
も行う状況を模式的に示す説明図である。さらに、図４
は、本実施形態の鋼管21のねじ切り方法の工程を模式的
に示すフロー図である。In the present embodiment, the tapered male screw portion 23 is
The description is omitted because it is the same as the tapered external thread portion of the known buttress joint. The incompletely threaded portion 22 is formed on the outer surface of the tube end adjacent to the externally tapered threaded portion 23 in the tube axis direction. At least a part of the incomplete screw portion 22 is formed in the externally machined portion 24 that has been subjected to external machining. That is,
Conventionally, external machining has been performed only in the formation range of the tapered male thread portion 23, and external machining has not been performed in the formation range of the incomplete thread portion 22. On the other hand, in the steel pipe 21 of the present embodiment, the external machining is performed not only on the formation range of the tapered external thread portion 23 but also on the formation range of the incomplete thread portion 22. Further, the external machining portion 24 in the present embodiment includes a tapered male screw portion.
To have a tube outer diameter d 3 is substantially constant at the same value as the maximum value d 2 of the tube outer diameter in the 23 region formation, it is formed. The external machining portion 24 is formed by performing external machining before forming the tapered external thread portion 23 and the incomplete thread portion 22. In addition, as shown in FIG. 1 (a), in the present embodiment, not the entire area of the incompletely threaded portion 22, but the two
External machining is performed up to the front of the mountain. Thereby, the final position of the thread engagement of each of the pin portion and the box portion can be made the same as the final position of the thread engagement of the conventional buttress joint, that is, joint strength ≧ pipe body strength, and Does not decrease tensile performance. The portion up to two threads before the thread cut-up portion 25 comes into contact with the box screw portion at the final stage of the joint tightening, so that the linearity of each of the pin portion and the box portion is ensured. Therefore, the influence on the tightening state is reduced, and the abnormal change of the tightening torque and the seizure of the screw portion are not generated.
When the buttress joint of this embodiment is tightened with an oil well, if the steel pipe 21 is inclined, the conventional incomplete threaded portion 22 ′ shown in FIG. 1B interferes with the tapered female thread 7. Thus, the incompletely threaded portion 22 of this embodiment shown in FIG.
Since the height of the thread, that is, the height of the burr is reduced by the external machining amount d 1 (= d 0 −d 2 ) 1 , the incomplete thread portion 22 does not interfere with the tapered female thread portion 7. [Method of Threading Steel Pipe 21] Next, this steel pipe of the present embodiment will be described.
The 21 thread cutting method will be described. FIG. 2 shows a pre-processing machine 28 having an internal cutting tool 26 and an external cutting tool 27 in this embodiment.
FIG. 5 is an explanatory view schematically showing a state in which all of the inner surface processing, the outer cutting processing, and the sealing part rough processing are performed on the steel pipe 21.
FIG. 3 shows a thread cutting tool in this embodiment.
FIG. 3 schematically shows a state in which a threading process, an external cutting process, and a sealing portion finishing process are all performed on a steel pipe 21 that has been pre-processed by a pre-processing machine 28 by a finishing machine 31 having a 29 and a sealing tool 30. FIG. Further, FIG.
FIG. 3 is a flowchart schematically showing steps of a method for cutting a steel pipe 21 of the present embodiment.
【００１６】図２および図４に示すように、内削工具2
6、外削工具27および図示しない端面加工工具を有する
前加工機28により、鋼管21の外面に外削加工を行って傾
斜部32と水平部33とを形成する。すなわち、傾斜部32と
水平部33とは、いずれも、図１における外削加工部24を
構成する。As shown in FIG. 2 and FIG.
6. The outer surface of the steel pipe 21 is externally machined by a pre-machining machine 28 having an external machining tool 27 and an end face machining tool (not shown) to form an inclined portion 32 and a horizontal portion 33. That is, both the inclined portion 32 and the horizontal portion 33 constitute the external machining portion 24 in FIG.
【００１７】後続して行われるねじ切り加工によって、
傾斜部32にテーパ雄ねじ部23の形成されるとともに水平
部33に不完全ねじ部22が形成される。また、前加工機28
により、鋼管21の端面加工および内面加工が行われる。
これらの加工の際、シール部の加工径を仕上げ寸法より
も一定量大きくしておくことが望ましい。なお、本実施
形態では、内削加工または端面加工を前加工機28により
行うこととしたが、これらの加工は、いずれも、仕上げ
加工機31により行うようにしてもよい。[0017] By the subsequent threading process,
The tapered male screw portion 23 is formed on the inclined portion 32 and the incomplete screw portion 22 is formed on the horizontal portion 33. Also, the pre-processing machine 28
Thereby, the end surface processing and the inner surface processing of the steel pipe 21 are performed.
At the time of these processes, it is desirable to make the processing diameter of the seal portion larger by a certain amount than the finished size. In the present embodiment, the internal machining or the end face machining is performed by the pre-machining machine 28, but any of these machining may be performed by the finishing machine 31.
【００１８】このようにして前加工を行われた鋼管21に
対して、図３および図４に示すように、外削加工された
水平部33に、仕上げ加工機31に設けられた芯出しチャッ
ク34を接触させることにより前加工機28における加工時
の芯位置と、仕上げ加工機31における加工時の芯位置と
を一致させる。As shown in FIGS. 3 and 4, the centering chuck provided in the finishing machine 31 is attached to the steel pipe 21 which has been pre-processed in this manner, as shown in FIGS. By bringing 34 into contact, the center position of the pre-processing machine 28 at the time of machining and the center position of the finishing machine 31 at the time of machining are matched.
【００１９】図５は、鋼管21を芯出しチャック34により
チャックする状況を模式的に示す説明図である。図４お
よび図５に示すように、２基の芯出しチャック34、34の
径方向移動量ａ、ｂに合わせて移動する管本体チャック
35で鋼管21をチャックする際に、２基の芯出しチャック
34、34の移動量ａ、ｂの差 (ａ−ｂ）を求めることによ
り、芯出しチャック34の位置と管本体チャック35の径方
向位置とが、前加工機28により前加工の際に残した仕上
げ加工機31でのねじ、シール部取り代以上にずれないよ
うに、管本体チャック35の移動量を管理する。FIG. 5 is an explanatory view schematically showing a situation in which the steel pipe 21 is chucked by the centering chuck 34. As shown in FIGS. 4 and 5, the pipe body chuck moves in accordance with the radial movement amounts a, b of the two centering chucks 34, 34.
When chucking steel pipe 21 with 35, two centering chucks
By calculating the difference (ab) between the movement amounts a and b of the pipes 34 and 34, the position of the centering chuck 34 and the radial position of the pipe body chuck 35 are left by the pre-processing machine 28 during the pre-processing. The moving amount of the pipe body chuck 35 is controlled so as not to shift more than the screw and seal portion allowance in the finishing machine 31.
【００２０】すなわち、差 (ａ−ｂ）が仕上げ加工機31
でのねじ、シール部取り代以上存在する場合には、まず
鋼管21の水平部33における切り粉の有無を確認し、切り
粉があるときには切り粉を除去して再度芯出しチャック
34による芯出しを行い、一方、切り粉がないときには前
加工不良があると判断して、管本体チャック35を作動さ
せずに仕上げ加工を中断し、前加工機28により前加工に
戻る。本実施形態では、このようにして、テーパ雄ねじ
部23および不完全ねじ部22の加工不良が未然に防止され
る。That is, the difference (ab) corresponds to the finishing machine 31.
If there is more than the screw and seal allowance, the presence of chips in the horizontal part 33 of the steel pipe 21 is checked first, and if there is chips, remove the chips and re-center the chuck.
The centering by 34 is performed. On the other hand, when there is no cutting powder, it is determined that there is a pre-processing defect, the finishing processing is interrupted without operating the pipe body chuck 35, and the pre-processing machine 28 returns to the pre-processing. In the present embodiment, in this manner, processing defects of the tapered male screw portion 23 and the incomplete screw portion 22 are prevented beforehand.
【００２１】図６は、従来の仕上げ加工機に附帯して設
けられた芯出しチャック34を示す説明図である。図６に
示すように、従来は、鋼管21' の傾斜部32に芯出しチャ
ック34を接触させて芯出しを行っていたが、傾斜部32は
軸方向で管の外削径が変動するために芯出しチャック34
が鋼管21' の傾斜部32に接触する位置が管軸方向に少し
でも変動すると、芯出しチャック34の移動量の検出値も
変動してしまい、芯ズレ防止装置の管理精度が低下して
しまう。これに対し、本実施形態では、水平部33を用い
て芯出しを行うため、芯出しチャック34が鋼管21の水平
部33に接触する位置が管軸方向に変動しても、前加工機
28における加工時の芯位置と、仕上げ加工機31における
加工時の芯位置とを高精度で一致させることができる。FIG. 6 is an explanatory view showing a centering chuck 34 provided in addition to a conventional finishing machine. As shown in FIG. 6, conventionally, the centering is performed by bringing the centering chuck 34 into contact with the inclined portion 32 of the steel pipe 21 '. However, since the outer cutting diameter of the pipe varies in the axial direction, the inclined portion 32 varies. Centering chuck 34
If the position at which the rod contacts the inclined portion 32 of the steel pipe 21 'fluctuates even slightly in the pipe axis direction, the detected value of the amount of movement of the centering chuck 34 also fluctuates, and the management accuracy of the misalignment prevention device is reduced. . On the other hand, in the present embodiment, since the centering is performed using the horizontal portion 33, even if the position where the centering chuck 34 contacts the horizontal portion 33 of the steel pipe 21 changes in the pipe axis direction, the pre-processing machine
The center position at the time of processing in 28 and the center position at the time of processing in the finishing machine 31 can be matched with high accuracy.
【００２２】このようにして、芯出しチャック34を用い
て前加工機28と仕上げ加工機31とにより鋼管21の軸芯を
合わせてから、管端加工部より奥に位置する左右２個の
管本体チャック35を用いて、鋼管21をチャックする。そ
して、ねじ切り加工工具29およびシール加工工具30を有
する仕上げ加工機31により、外削加工を行われた傾斜部
32と水平部33とに、ねじ切り加工およびシール加工を行
う。この不完全ねじ部22を有する本実施形態の鋼管21
は、以下に列記する効果(i)〜効果(iv)を奏することが
できる。 (i) 不完全ねじ部22におけるかえりの発生程度が均一化
および最小化されるため、従来と同様にバフ砥石等を用
いてかえりの研削除去を行うことにより、かえり取りを
確実かつ容易に行うことができる。 (ii)かえりの発生程度が均一化および最小化されること
により、かえり取りを確実かつ容易に行うことができる
ため、油井使用時の締め付けトルクの異常な変化やねじ
部の焼き付きの発生を、いずれも防止でき、これによ
り、鋼管21の取扱い性が向上する。 (iii) 不完全ねじ部22' の形成範囲には外削加工を行わ
ない従来の加工方法では、不完全ねじ部22' は、鋼管肌
を呈しており不連続な凹凸がある。このため、ねじ切り
時にねじ切り加工工具の破損が多発していた。しかし、
本実施形態では、不完全ねじ部22のねじ切り時には外削
加工部24が形成されているため、加工中のねじ切り加工
工具に作用する負荷が低減かつ安定化され、工具寿命が
著しく向上する。 (iv)前加工機28と仕上げ加工機31との２台の加工機でね
じ継手を加工する際に、仕上げ加工機31でのシール部加
工取り代を一定量残すとともに、傾斜部32および水平部
33を残して前加工機28で加工した後、仕上げ加工機31の
芯出し時には、外削加工を行われた水平部33を利用して
芯出しチャック34により鋼管21のチャックを行うことに
より、本体チャック35の芯ずれが仕上げ加工機31でのシ
ール部加工取り代を超えて発生した場合には前加工不良
と判断して、加工を中止することができる。このため、
テーバ雄ねじ部23および不完全ねじ部22の加工不良の発
生率を、顕著に低減できる。In this way, the center of the steel pipe 21 is aligned by the pre-processing machine 28 and the finishing processing machine 31 using the centering chuck 34, and then the two left and right pipes located deeper than the pipe end processing portion are formed. The steel pipe 21 is chucked using the main body chuck 35. Then, by the finishing machine 31 having the thread cutting tool 29 and the seal machining tool 30, the inclined portion subjected to the external machining is performed.
Thread cutting and sealing are performed on the 32 and the horizontal portion 33. Steel pipe 21 of the present embodiment having this imperfect thread portion 22
Can produce the effects (i) to (iv) listed below. (i) Since the degree of burrs in the incomplete thread portion 22 is uniformed and minimized, the burrs are removed by grinding and removing the burrs using a buffing wheel or the like in the same manner as in the prior art, so that the burrs are reliably and easily performed be able to. (ii) By uniformizing and minimizing the degree of burrs, burrs can be reliably and easily performed.Therefore, abnormal changes in the tightening torque and seizure of the screw part when using an oil well can be prevented. Either of them can be prevented, thereby improving the handleability of the steel pipe 21. (iii) In the conventional machining method in which external machining is not performed in the formation area of the incomplete threaded portion 22 ', the incompletely threaded portion 22' has a steel pipe skin and has discontinuous irregularities. For this reason, the threading tool was frequently damaged during threading. But,
In the present embodiment, since the external machining portion 24 is formed when the incomplete thread portion 22 is threaded, the load acting on the threading tool during machining is reduced and stabilized, and the tool life is significantly improved. (iv) When processing a threaded joint with two processing machines, the pre-processing machine 28 and the finishing processing machine 31, while leaving a certain amount of seal part processing allowance in the finishing processing machine 31, the inclined portion 32 and the horizontal Department
After processing with the pre-processing machine 28 leaving 33, at the time of centering of the finishing processing machine 31, by chucking the steel pipe 21 with the centering chuck 34 using the horizontal part 33 subjected to external machining, If the misalignment of the main body chuck 35 occurs beyond the seal portion machining allowance in the finishing machine 31, it is determined that the pre-machining is defective, and the machining can be stopped. For this reason,
The occurrence rate of machining failure of the tapered male screw portion 23 and the incomplete screw portion 22 can be significantly reduced.
【００２３】このため、本実施形態によれば、かえりの
発生に起因した締め付けトルクのハンピング、ねじ部で
の焼き付きさらには油井での降管作業時間の長時間化を
いずれも解決できるとともに、前加工機と仕上げ加工機
との２台の加工機でピン部を加工した場合の芯ずれ、加
工不良率の低下さらには気密不良の発生をいずれも解決
できる。Therefore, according to the present embodiment, it is possible to solve the problem of the humping of the tightening torque, the seizure of the screw portion, and the prolongation of the downtime of the pipe in the oil well due to the occurrence of burrs. It is possible to solve the problem of the misalignment, the reduction in the processing defect rate, and the occurrence of poor airtightness when the pin portion is processed by the two processing machines of the processing machine and the finishing processing machine.
【００２４】[0024]
【実施例】(実施例１)海上油井において、外径：177.8
mm、厚さ：10.36 mmであって不完全ねじ部には外削加工
を行っていない従来例の金属密封面付きの特殊継手と、
同じ外径であって不完全ねじ部にも外削加工を行った本
発明例の金属密封面付きの特殊継手とのそれぞれについ
て、締め付け作業を行った。なお、テーパ雄ねじ部の長
さは40mm、不完全ねじ部の水平部の長さは80mmとし、仕
上げ加工における加工代は0.3mmに設定した。また、芯
ずれの管理値は0.6 mmとした。そして、前述したハンピ
ングの発生率 (％) と、降管能率 (本／時）とを測定し
た。結果を表１にまとめて示す。[Example] (Example 1) In an offshore oil well, outer diameter: 177.8
mm, thickness: 10.36 mm, a special joint with a metal sealing surface of the conventional example, which is not externally machined for incomplete threaded parts,
Tightening work was performed on each of the special joints having a metal sealing surface according to the present invention example having the same outer diameter and also having the external thread machining performed on the imperfect thread portion. In addition, the length of the tapered male thread portion was 40 mm, the length of the horizontal portion of the incomplete thread portion was 80 mm, and the machining allowance in the finishing process was set to 0.3 mm. The control value of misalignment was 0.6 mm. Then, the occurrence rate (%) of the above-mentioned humping and the downcoming efficiency (book / hour) were measured. The results are summarized in Table 1.
【００２５】[0025]
【表１】 [Table 1]
【００２６】表１に示す通り、不完全ねじ部に外削加工
を行っていない従来例では、ハンピングの発生率が75.0
％であったのに対し、不完全ねじ部に外削加工をおこな
った本発明例ではハンピングの発生率は、7.6 ％に約1/
10に低減された。これにより、作業時間が短縮され、降
管能率も約２倍に改善された。 （実施例２）外径177.8 mmの油井管それぞれ100 本を、
不完全ねじ部には外削加工を行っていない従来法と、不
完全ねじ部にも外削加工を行った図１〜図４に示す本発
明法とにより、加工した。本発明法では、仕上げ加工機
31でのシール部加工取り代（＝前加工機での外削寸法と
仕上げ寸法との差）は、径方向寸法で0.6 mmとした。さ
らに、仕上げ加工機31に設けられる芯出しチャック34
は、水平部33に位置するようにした。そして、テーバ雄
ねじ部23および不完全ねじ部22の加工不良の発生数を測
定した。結果を表２にまとめて示す。As shown in Table 1, in the conventional example in which the external machining was not performed on the incomplete thread portion, the occurrence rate of humping was 75.0%.
%, Whereas in the present invention example in which external machining was performed on the incomplete thread portion, the occurrence rate of humping was reduced to about 1 / 7.6 to 7.6%.
Reduced to 10. As a result, the working time was shortened, and the evacuation efficiency was improved about twice. (Example 2) 100 oil well pipes each having an outer diameter of 177.8 mm were
The incompletely threaded portion was machined by a conventional method in which external machining was not performed, and the incompletely threaded portion was machined by the method of the present invention shown in FIGS. In the method of the present invention, a finishing machine
The machining allowance for the seal portion at 31 (= the difference between the external cutting dimension and the finishing dimension in the pre-processing machine) was 0.6 mm in the radial direction. Further, a centering chuck 34 provided in the finishing machine 31 is provided.
Is located in the horizontal portion 33. Then, the number of occurrences of processing defects of the Taber male screw portion 23 and the incomplete screw portion 22 was measured. The results are summarized in Table 2.
【００２７】[0027]
【表２】 [Table 2]
【００２８】表２に示すように、不完全ねじ部に外削加
工を行っていない従来方法では、シール未加工不良が発
生するが、不完全ねじ部にも外削加工を行った図１〜図
４に示す本発明法を使用すれば、シール部未加工不良を
未然に防止することが可能であることがわかる。As shown in Table 2, in the conventional method in which the external machining is not performed on the incomplete thread portion, a seal unprocessed defect occurs, but the external machining is also performed on the incomplete thread portion. It can be seen that the use of the method of the present invention shown in FIG. 4 makes it possible to prevent a defective seal portion from being processed.
【００２９】また、この際に、従来法および本発明法の
双方について、仕上げ加工機31のねじ切り加工工具29の
寿命を測定した。結果を表３にまとめて示す。At this time, the life of the threading tool 29 of the finishing machine 31 was measured for both the conventional method and the method of the present invention. The results are summarized in Table 3.
【００３０】[0030]
【表３】 [Table 3]
【００３１】表３に示すように、不完全ねじ部にも外削
加工を行った図１〜図４に示す本発明法を使用すれば、
ねじ切り加工工具の寿命を従来よりも60％程度向上させ
ることができたことがわかる。 (変形形態)上記の実施の形態および実施例の説明では、
鋼管が油井管である場合を例にとった。しかし、本発明
はこの形態には限定されず、例えばガス井管等の油井管
以外の鋼管に対しても同様に適用される。As shown in Table 3, if the method of the present invention shown in FIGS.
It can be seen that the life of the thread cutting tool was able to be improved by about 60% as compared with the conventional one. (Modification) In the description of the above embodiment and examples,
The case where the steel pipe is an oil well pipe is taken as an example. However, the present invention is not limited to this form, and is similarly applied to steel pipes other than oil well pipes such as gas well pipes.
【００３２】また、実施の形態および実施例の説明で
は、加工工具が固定配置された鋼管の周囲を回転しなが
ら加工を行う場合を例にとった。しかし、本発明はこの
形態には限定されす、固定配置された加工工具の近傍に
鋼管を回転させながら加工を行う場合であっても、等し
く適用される。Further, in the description of the embodiment and the examples, the case where the working is performed while rotating around the steel pipe on which the working tool is fixedly arranged is taken as an example. However, the present invention is not limited to this mode, and is equally applicable to the case where the machining is performed while rotating the steel pipe near the fixedly arranged machining tool.
【００３３】また、実施の形態および実施例の説明で
は、継手がバットレス継手である場合を例にとった。し
かし、本発明はこの形態には限定されず、例えば特殊継
手等のバットレス継手以外の他の継手についても、同様
に適用される。In the description of the embodiment and the examples, the case where the joint is a buttress joint is taken as an example. However, the present invention is not limited to this form, and is similarly applied to other joints other than the buttress joint such as a special joint.
【００３４】また、実施の形態および実施例の説明で
は、外削加工部が、テーパ雄ねじ部の形成領域における
管外径の最大値と同じ値で略一定である管外径を有する
ように、形成された場合を例にとった。しかし、本発明
はこの形態には限定されず、外削加工を行われていれ
ば、その加工形状は限定を要さない。すなわち、本発明
は、不完全ねじ部の少なくとも一部が外削加工を行われ
た外削加工部に設けられたものであれば、等しく適用さ
れる。Also, in the description of the embodiment and the examples, the externally machined portion has the same value as the maximum value of the tube outer diameter in the region where the tapered male screw portion is formed, and has a substantially constant tube outer diameter. The case where it was formed was taken as an example. However, the present invention is not limited to this form, and the shape of the machining need not be limited as long as the external machining is performed. That is, the present invention is equally applicable as long as at least a part of the incompletely threaded portion is provided in the externally machined portion subjected to the external machining.
【００３５】さらに、実施の形態および実施例の説明で
は、不完全ねじ部のうちの２山を除いた部分に、外削加
工が行われた場合を例にとった。しかし、本発明はこの
形態には限定されず、不完全ねじ部の少なくとも一部に
外削加工が行われたものであれば、等しく適用される。Further, in the description of the embodiment and the examples, the case where the external machining is performed on a portion excluding the two ridges of the incomplete thread portion is taken as an example. However, the present invention is not limited to this form, and is equally applicable as long as at least a part of the incompletely threaded portion is externally machined.
【００３６】[0036]
【発明の効果】以上詳細に説明したように、本発明によ
り、(i) かえりの発生を最小限に抑制できるためにかえ
りの発生に起因した締め付けトルクのハンピング、ねじ
部での焼き付きさらには油井での降管作業時間の長時間
化をいずれも解決するとともに、ねじ切り加工工具に作
用する負荷を安定させてねじ切り加工工具の長寿命化を
図ることができるとともに、(ii)前加工機と仕上げ加工
機との２台の加工機でピン部を加工した場合の芯ずれ、
加工不良率の低下さらには気密不良の発生をいずれも解
決することができ、これにより、シール部未加工品を油
井で使用することによる油井事故を未然に防止すること
ができる。As described in detail above, according to the present invention, (i) the occurrence of burrs can be suppressed to a minimum, so that the humping of the burrs caused by the occurrence of burrs, the seizure in the screw portion, and the oil well In addition to resolving the lengthening of the downcoming work time in the process, the load acting on the threading tool can be stabilized and the life of the threading tool can be extended, and (ii) the finishing machine and finishing Misalignment when the pin part is processed by two processing machines with the processing machine,
It is possible to solve both the reduction in the processing defect rate and the occurrence of poor airtightness, thereby preventing an oil well accident caused by using an unprocessed product of the seal portion in the oil well.
【００３７】かかる効果を有する本発明の意義は、極め
て著しい。The significance of the present invention having such effects is extremely remarkable.
【図１】図１(a) は、実施形態の鋼管の不完全ねじ部を
拡大して示す説明図であり、図１(b) は、従来の不完全
ねじ部の噛み合いを示す説明図であり、図１(c) は、実
施形態の不完全ねじ部の噛み合いを示す説明図である。FIG. 1 (a) is an enlarged view showing an incompletely threaded portion of a steel pipe according to an embodiment, and FIG. 1 (b) is an explanatory diagram showing the engagement of a conventional incompletely threaded portion. FIG. 1C is an explanatory diagram showing the engagement of the incompletely threaded portion of the embodiment.
【図２】実施形態において、内削工具および外削工具を
有する前加工機により、鋼管に内面加工、外削加工およ
びシール部粗加工をいずれも行う状況を模式的に示す説
明図である。FIG. 2 is an explanatory diagram schematically showing a state in which a pre-machining machine having an internal cutting tool and an external cutting tool performs all internal surface processing, external cutting, and rough sealing at a steel pipe in the embodiment.
【図３】実施形態において、ねじ切り加工工具およびシ
ール加工工具を有する仕上げ加工機により、前加工機に
よる前加工を行われた鋼管に、ねじ切り加工、外削加工
およびシール部仕上げ加工をいずれも行う状況を模式的
に示す説明図である。FIG. 3 is a diagram showing an embodiment in which a finishing machine having a threading tool and a sealing tool performs all of threading, external machining, and sealing part finishing on a steel pipe that has been pre-machined by the pre-machining machine. It is explanatory drawing which shows a situation typically.
【図４】実施形態の鋼管のねじ切り方法の工程を模式的
に示すフロー図である。FIG. 4 is a flowchart schematically showing steps of a method for cutting a steel pipe according to the embodiment.
【図５】鋼管を芯出しチャックによりチャックする状況
を模式的に示す説明図である。FIG. 5 is an explanatory view schematically showing a situation in which a steel pipe is chucked by a centering chuck.
【図６】従来の仕上げ加工機に附帯して設けられた芯出
しチャックを示す説明図である。FIG. 6 is an explanatory view showing a centering chuck attached to a conventional finishing machine.
【図７】バットレス継手の一例を部分的に示す説明図で
ある。FIG. 7 is an explanatory view partially showing an example of a buttress joint.
【図８】特殊継手の一例を部分的に示す説明図である。FIG. 8 is an explanatory view partially showing an example of a special joint.
【図９】図９(a) は、かえりが発生したねじ山を示す説
明図であり、図９(b) は、バフ砥石等を用いてかえりの
研削除去が行われた後のねじ山を示す説明図である。FIG. 9 (a) is an explanatory view showing a thread in which burrs are generated, and FIG. 9 (b) is a view showing a thread after burrs are removed by grinding using a buffing wheel or the like. FIG.
【図１０】図10(a) はかえりがテーパ雌ねじ部と干渉す
る状況を示す説明図であり、図10(b) はかえりがテーパ
雌ねじ部と干渉する状況を示す説明図である。FIG. 10 (a) is an explanatory view showing a situation in which the burrs interfere with the tapered female thread portion, and FIG. 10 (b) is an explanatory view showing a situation in which the burrs interfere with the tapered female thread portion.
【図１１】ねじ山にかえりが発生した不完全ねじ部を有
する継手について、発生トルク (締め付けトルク) に及
ぼす締め付け回数の影響を示すグラフである。FIG. 11 is a graph showing the effect of the number of tightening times on the generated torque (tightening torque) for a joint having an incomplete thread portion in which burrs have occurred on a thread.
21 鋼管 22 不完全ねじ部 23 テーパ雄ねじ部 24 外削加工部 21 Steel pipe 22 Incomplete thread part 23 Taper male thread part 24 External machining part
Claims (4)
る不完全ねじ部を備え、該不完全ねじ部の少なくとも一
部は、外削加工を行われた外削加工部に設けられること
を特徴とする鋼管。An incomplete thread portion adjacent to a tapered external thread portion is provided on an outer surface of a pipe end portion, and at least a part of the incomplete thread portion is provided in an externally machined portion which has been machined externally. Characterized by a steel pipe.
の形成領域における管外径の最大値と同じ値で略一定で
ある管外径を有するように、形成される請求項１に記載
された鋼管。2. The external machining portion is formed so as to have a pipe outer diameter which is substantially the same as the maximum value of the pipe outer diameter in a region where the tapered external thread portion is formed. Steel pipe.
加工を行うことにより外削加工部を設けた後に、該外削
加工部に、テーパ雄ねじ部に隣接する不完全ねじ部の少
なくとも一部を設けることを特徴とする鋼管のねじ切り
方法。3. An external machining portion is provided by performing external machining from a pipe end surface of a steel pipe in a tube axis direction, and then the externally machined portion is provided with an incomplete thread portion adjacent to a tapered male thread portion. A method for cutting a steel pipe, wherein at least a part is provided.
の形成領域における管外径の最大値と同じ値で略一定で
ある管外径を有するように、形成される請求項３に記載
された鋼管のねじ切り方法。4. The external machining portion according to claim 3, wherein the externally machined portion is formed so as to have a substantially same tube outer diameter as a maximum value of the tube outer diameter in a region where the tapered male screw portion is formed. Steel pipe threading method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29958799A JP3767282B2 (en) | 1999-10-21 | 1999-10-21 | Steel pipe and its threading method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29958799A JP3767282B2 (en) | 1999-10-21 | 1999-10-21 | Steel pipe and its threading method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005330276A Division JP4277845B2 (en) | 2005-11-15 | 2005-11-15 | Oil well or gas well |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001124254A true JP2001124254A (en) | 2001-05-11 |
| JP3767282B2 JP3767282B2 (en) | 2006-04-19 |
Family
ID=17874572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29958799A Expired - Fee Related JP3767282B2 (en) | 1999-10-21 | 1999-10-21 | Steel pipe and its threading method |
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| Country | Link |
|---|---|
| JP (1) | JP3767282B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012247028A (en) * | 2011-05-30 | 2012-12-13 | Jfe Steel Corp | Screw joint for steel pipe |
| JP2012247027A (en) * | 2011-05-30 | 2012-12-13 | Jfe Steel Corp | Screw joint for steel pipe |
| CN102943633A (en) * | 2012-10-10 | 2013-02-27 | 中国石油天然气集团公司 | Threaded connection structure |
-
1999
- 1999-10-21 JP JP29958799A patent/JP3767282B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012247028A (en) * | 2011-05-30 | 2012-12-13 | Jfe Steel Corp | Screw joint for steel pipe |
| JP2012247027A (en) * | 2011-05-30 | 2012-12-13 | Jfe Steel Corp | Screw joint for steel pipe |
| CN102943633A (en) * | 2012-10-10 | 2013-02-27 | 中国石油天然气集团公司 | Threaded connection structure |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3767282B2 (en) | 2006-04-19 |
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