JPS5821087A - Structure of joint section of pipe end - Google Patents

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

【発明の詳細な説明】 開示技術は油井管等に用いるユニット管相互のカップリ
ングを介した継手連結技術の分野に属する。DETAILED DESCRIPTION OF THE INVENTION The disclosed technology belongs to the field of joint connection technology through mutual coupling of unit pipes used in oil country tubular goods and the like.

而して、この発明は所定長ユニット管の管端にテーパ部
とオネジ部が形成されており、これに対し該ユニット管
相互を連結するカップリング管継手が該テーパ部密着す
るテーパ部と該オネジ部に螺合緊結するメネジ部を形成
されている管端継手部構造に関するものであり、特ｌこ
、管端オネジ部の先に設けたテーパ部に螺合圧入による
圧縮歪変形が半径、及び、軸方向に形成される様にし、
而して半径方向歪が少くとも弾性歪領域を越えて、塑性
変形とされる嵌合代を与えられ、一方、軸方向圧縮代が
同じく弾性歪領域を越えて塑性変形とされる長さとして
与えている端部圧縮残留応力形成管端部継手構造に係る
ものである。In this invention, a tapered part and a male screw part are formed at the pipe end of a unit pipe of a predetermined length, and a coupling pipe joint that connects the unit pipes has a taper part that comes into close contact with the tapered part and a male thread part. This relates to the structure of a pipe end joint in which a female threaded part is formed to be tightly screwed to a male threaded part. and formed in the axial direction,
Therefore, the radial strain exceeds at least the elastic strain region, giving a fit length that is considered plastic deformation, while the axial compression distance also exceeds the elastic strain region, giving a length that is considered plastic deformation. The present invention relates to a pipe end joint structure that creates compressive residual stress at the end.

周知の如く、油井管等に於ては肢管の製造時の装置の制
約や、輸送上の規制等によりユニット管の管長が決めら
れており、従って、現地配管に際しては該ユニット管の
相互接合が行われるが、接合の迅速さ、確実な脱着性、
交換性、シール性等の点でカップリングによる管継手が
多く用いられている。As is well known, in oil country tubing, etc., the length of unit pipes is determined by restrictions on equipment during the manufacture of limbs, transportation regulations, etc. Therefore, when on-site piping, unit pipes must be joined together. However, the speed of joining, reliable removability,
Pipe joints based on couplings are often used due to their replaceability and sealability.

而して、近時腐蝕性流体や、危険性流体の輸送がさまざ
まな方面で採用される様になると、該種カップリング管
継手に於ても単なるネジ連結ではネジ部シールが連結を
兼ねるため充分でない欠点があった。Recently, as the transportation of corrosive and dangerous fluids has come to be used in various fields, even in these types of coupling pipe fittings, the threaded seal also serves as the connection. There was a drawback that it was not sufficient.

これに対処するに、第１図に示す様にユニット管１の管
端部２にオネジ３を刻設し、先端にテーパ部４を形成し
、一方、カップリング継手５に対応メネジ６を刻設する
と共に中央にテーパ部７を形成し、ネジ部３，６により
緊結圧入を図り、テーパ部４．７のメタルタッチ締付け
によりシールを行う様な技術が案出採用されて来ている
。To deal with this, as shown in FIG. At the same time, a technique has been devised and adopted in which a tapered part 7 is formed in the center, the threaded parts 3 and 6 are used to securely press fit the tapered part 4.7, and a seal is achieved by metal touch tightening of the tapered part 4.7.

従って、該種継手ではネジ部３，６とテーパ部４．７と
の相互の緊結に係る管理が極めて難しい難点があり、一
応のシール性が得られても稼動中の種々の振動等により
ネジ緩みが生じたりするとシール性が甘くなったりする
不利点があり、加えて、単なるメタルタッチで圧縮力が
弱まると応力腐蝕割れを生ずる等の不具合もあった。Therefore, this type of joint has the disadvantage that it is extremely difficult to manage the mutual tightness between the threaded parts 3, 6 and the tapered part 4.7, and even if a certain degree of sealing performance is obtained, the threads may be damaged due to various vibrations during operation. If loosening occurs, there is a disadvantage that the sealing performance becomes weak, and in addition, if the compressive force is weakened by mere metal touch, there are other problems such as stress corrosion cracking.

この発明の目的は上述従来技術に基づくカップリング継
手の問題点に鑑み、ネジ部の緊結とテーパ部のメタルタ
ッチシールの機能分離のメリットを生かすと共にテーパ
部の弾性を利用し圧縮し、半径方向に塑性変形させ、又
、軸方向にも同等以上の塑性変形を与えて端部に圧縮残
留応力を付与して密着性を良くシ、シール性を確保し、
応力腐蝕割れを防止し得る優れた管端継手構造を提供せ
んとするものである。In view of the problems of the coupling joint based on the prior art described above, the purpose of the present invention is to take advantage of the functional separation of the tightening of the threaded part and the metal touch seal of the tapered part, and to compress the tapered part by utilizing its elasticity. plastic deformation to the same extent or greater in the axial direction to impart compressive residual stress to the ends to improve adhesion and ensure sealing.
The present invention aims to provide an excellent pipe end joint structure that can prevent stress corrosion cracking.

上述目的に沿うこの発明の構成はユニット管とカップリ
ング継手をネジ部を介して螺合していくと、管端テーパ
部先端がカップリング継手テーパ部に当接し、更に締め
込んでいくと、該テーパ部先端は弾性歪で変形し内側に
圧縮されていき、先端が全てメタルタッチ状になると該
テーパ部先端の径方向型は弾性歪領域を越えて降伏し、
塑性変形し始めると共に軸方向も圧縮変形され、その歪
は弾性歪領域を越えて半径方向型と等しいかそれ以上に
され、その結果、径、及び、軸方向共に圧縮残留応力が
付与され、シール性が確保され、応力腐蝕割れが生じな
い様にしたことを要旨とするものである。The structure of the present invention that meets the above-mentioned object is that when the unit pipe and the coupling joint are screwed together through the threaded part, the tip of the tapered part of the pipe end comes into contact with the taper part of the coupling joint, and as the unit pipe is further tightened, The tip of the tapered portion is deformed by elastic strain and compressed inward, and when the tip becomes completely metal-touched, the radial mold at the tip of the tapered portion exceeds the elastic strain region and yields.
As the plastic deformation begins, the axial direction is also compressively deformed, and the strain exceeds the elastic strain region and becomes equal to or greater than the radial direction. As a result, compressive residual stress is applied in both the radial and axial directions, and the seal The main purpose is to ensure the properties of the steel and to prevent stress corrosion cracking from occurring.

次にこの発明の１実施例を第２図以下の図面に基づいて
説明すれば以下の通りである。Next, one embodiment of the present invention will be described below based on the drawings from FIG. 2 onwards.

図示実施例は油井管の態様であり、所定長、直径、肉厚
の炭素鋼製ユニット管８はその管端部９にオネジ部゛１
０を刻設されており、該オネジ部１０に接続し、且つ、
先端に於てΔＲの半径方向の嵌合代をもつ如く作られた
テーパ部１１に形成されメタルタッチ部１２はオーバー
ハング状に形成されている。The illustrated embodiment is an oil country tubular structure, in which a carbon steel unit pipe 8 having a predetermined length, diameter, and wall thickness has a male threaded portion 1 at its end 9.
0 is carved, connects to the male threaded part 10, and
The metal touch portion 12 is formed in a tapered portion 11 having a radial fitting margin of ΔR at the tip end, and is formed in an overhang shape.

而して、該ΔＲは嵌合代とされるものであり、後述少く
とも弾性歪の領域を越えて半径方向に塑性変形させる量
であり、嵌合後テーパ内外面の大部分が緊結する様に設
計されている。The ΔR is considered to be the fitting margin, which is the amount of plastic deformation in the radial direction that exceeds at least the elastic strain region described later, and is such that most of the inner and outer surfaces of the taper are tightly connected after fitting. It is designed to.

そしてその長さｌについても後述カップリング継手に対
して緊結される過程で上記径方向嵌合代ΔＲに等しいか
、越える量の圧縮代であって少くとも弾性歪領域を越え
て塑性変形する圧縮代Δｌを与える長さにされている。The length l is also a compression margin that is equal to or exceeds the radial fitting margin ΔR during the process of being tightened to the coupling joint described later, and is at least a compression margin that plastically deforms beyond the elastic strain region. The length is set to give a margin Δl.

一方、１３はカップリング継手であり、両側に上記オネ
ジ部１０に対応するメネソ部１４が刻設され、その内側
には緊締テーパ部１５が内端に上−記メタルタッチ部１
６が形成され、上記嵌合代ΔＲ１及び、圧縮代Δｌを形
成する様にされている。On the other hand, reference numeral 13 denotes a coupling joint, which is provided with a male screw portion 14 corresponding to the male screw portion 10 on both sides, and a tightening taper portion 15 at the inner end thereof.
6 is formed to form the fitting allowance ΔR1 and the compression allowance Δl.

上述構成に於て、第２図に示す様にユニット管８側に対
しカップリング継手１３を近接回転させていくと、（勿
論逆でも良いが）テーパオネジ部１０に対してテーパメ
ネジ部１４が螺合し、螺合終期近くで第３図に示す様に
ユニット管８側のテーパ部１１の先端がカップリング継
手１３のテーパ部１５に線接触し、更に、最後の螺合を
進めて締めつけていくと、テーパ部１１の先端は弾性的
に内側に曲がり始め、第４図に示す様にその先端のオー
バーハング部のメタルタッチ部１２がカップリング継手
のバンダーバングメタルタッチ部１６に面当接すると共
に設計に基づいて弾性歪領域を越えて降伏し、塑性変形
し、ΔＲ径の嵌合代が得られ、ユニット管８、カップリ
ング継手共管テーパ部１１．１５内外面の大部分は緊結
され、且つ、第４図から第５図に示す様にテーパ部１１
は軸方向に圧縮変形されていき、その変形は同じく弾性
歪領域を越え降伏し、塑性変形し、しかも、上記半径方
向型ΔＲに対して最終軸方向圧縮変形歪量ΔｌがΔｌ≧
ΔＲである様にされる。In the above configuration, as shown in FIG. 2, when the coupling joint 13 is rotated close to the unit pipe 8 side, the tapered female threaded portion 14 is screwed into the tapered male threaded portion 10 (though of course it may be reversed). Then, near the end of the screwing, as shown in Figure 3, the tip of the tapered part 11 on the unit pipe 8 side comes into line contact with the tapered part 15 of the coupling joint 13, and the final screwing is further advanced and tightened. Then, the tip of the tapered portion 11 begins to elastically bend inward, and as shown in FIG. Based on the design, it yields and plastically deforms beyond the elastic strain region, and a fitting allowance of ΔR diameter is obtained, and most of the inner and outer surfaces of the unit pipe 8 and coupling joint common pipe taper part 11.15 are tightly connected, and , as shown in FIGS. 4 to 5, the tapered portion 11
is compressively deformed in the axial direction, and the deformation also exceeds the elastic strain region, yields, and becomes plastically deformed.Moreover, with respect to the radial type ΔR, the final axial compressive deformation strain Δl is Δl≧
ΔR.

従って、第５図に示す様に最終締結接合完了状態でのカ
ップリング継手１３に対するユニット管８側端部ではテ
ーパ部１１は全体、或は、大部分が密着メタルタッチ状
でシールされるばかりでなく、径方向、軸方向共に少く
とも弾性変形を越えて降伏し、塑性変形され、その結果
、圧縮残留応力を付与される。Therefore, as shown in FIG. 5, at the end of the unit pipe 8 with respect to the coupling joint 13 in the final fastened state, the tapered part 11 is entirely or mostly sealed with a close metal touch. Instead, it yields at least beyond elastic deformation in both the radial and axial directions, is plastically deformed, and as a result is given compressive residual stress.

そのため、流体輸送稼動させても弾性に弛みが生じたり
、又、応力腐蝕割れが生じたりはしない。Therefore, even when fluid transport is operated, elasticity does not loosen, and stress corrosion cracking does not occur.

尚、この発明の実施態様は上述実施例に限ることなく、
例えば、外管炭素鋼、内管ステンレス鋼等の耐蝕二重管
でも良く、又、ネジ螺合時焼ばめ、冷しばめ方式を採用
する等種々の態様が採用可能であることは勿論である。Note that the embodiments of this invention are not limited to the above-mentioned embodiments,
For example, a corrosion-resistant double tube made of carbon steel for the outer tube and stainless steel for the inner tube may be used, and it is of course possible to adopt various methods such as shrink fit or cold fit when screwed together. It is.

上述の如く、この発明によれば、基本的にユニット管の
カップリング継手に対する接合がネジ部とテーパ部で締
結、及び、圧縮応力による耐蝕性とシール確保を分化し
たことにより前者は連結と締結に強く与り、後者は残留
圧縮応力による耐蝕性とシール確保に与る優れた効果が
奏される。As described above, according to the present invention, the unit pipe is basically joined to the coupling joint by the threaded part and the tapered part, and the former is connected and fastened by differentiating between corrosion resistance due to compressive stress and sealing. The latter has excellent effects on corrosion resistance and sealing due to residual compressive stress.

而して、管端テーパ部の径方向に於て弾性歪領域を越え
て塑性変形圧縮させることにより強固な嵌合代が得られ
るのみならず、稼動中振動等による弛み防止に与る優れ
た効果があり、圧縮残留応力が付与されるので稼動中の
応力腐蝕割れも防止出来、局部的に降伏するので密着性
も向上し、シール性が格段に向上する効果も奏される。By plastically deforming and compressing the tapered portion of the pipe end in the radial direction beyond the elastic strain region, not only a strong fitting margin can be obtained, but also an excellent material that prevents loosening due to vibration during operation. It is effective, and since compressive residual stress is applied, stress corrosion cracking during operation can be prevented, and as it locally yields, adhesion is improved, and sealing performance is significantly improved.

そして、軸方向に対しても同じく弾性歪領域を越えて塑
性変形させるぬめ同じく密着性が向上し、シール性が良
くなり、圧縮残留応力による応力腐蝕割れが防止出来る
優れた効果があるに止まらず、軸方向圧縮歪量が径方向
歪量に等しいかそれより大きい様にしたことにより、稼
動中の緩みを防止し、流体流過面でのシール性、応力腐
蝕割れ防止の効果をより大きくされている効果がある。In addition, in the axial direction, the adhesiveness of the slime plastically deformed beyond the elastic strain region is similarly improved, the sealing performance is improved, and stress corrosion cracking due to compressive residual stress can be prevented. First, by making the axial compressive strain equal to or larger than the radial strain, loosening during operation is prevented, and the sealing performance on the fluid flow surface and the effect of preventing stress corrosion cracking are increased. There is a certain effect.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来技術に基づく管端継手部構造の概略説明図
、第２図以下はこの発明の１実施例の説明図であり、第
２図はユニット管とカップリング継手の螺合近接説明図
、第６図はテーパ部当接状態説明図、第４図はメタルタ
ッチ状態説明図、第５図は連結完了状態説明図である。 １１・・・テーパ部、　　１０・・・オネジ部、９・・
・管端、　　　　　　１５・・・テーパ部、１４・・・
メネジ部、　　　１３・・・管継手（カップリング）、
ΔＲ・・・嵌合代、　　　　Δｌ・・・圧縮代第１図FIG. 1 is a schematic explanatory diagram of the structure of a pipe end joint based on the prior art, FIG. FIG. 6 is an explanatory diagram of a taper portion contact state, FIG. 4 is an explanatory diagram of a metal touch state, and FIG. 5 is an explanatory diagram of a connection completed state. 11...Tapered part, 10...Male thread part, 9...
・Pipe end, 15...Tapered part, 14...
Female thread part, 13...pipe joint (coupling),
ΔR...Fitting allowance, Δl...Compression allowance Fig. 1

Claims (1)

【特許請求の範囲】[Claims] テーパ部とオネジ部を有している管端とこれに対応する
テーパ部とメネジ部を有している管継手とから成る管端
継手部構造において、上記の管端にオネジ部が刻設され
ると共に該オネジ部の先端テーパ部に少くとも弾性歪の
領域を越える半径方向変形を与える嵌合代が形成され、
且つ軸方向にて少くとも弾性歪領域を越えて上記半径方
向変形以上の変形を与える圧縮代が形成されていること
を特徴とする管端部継手構造。In a pipe end joint structure consisting of a pipe end having a tapered part and a male thread, and a corresponding pipe fitting having a tapered part and a female thread, the male thread is carved into the pipe end. At the same time, a fitting allowance is formed in the tapered tip portion of the male thread portion to provide radial deformation exceeding at least an elastic strain range,
A pipe end joint structure characterized in that a compression allowance is formed in the axial direction at least beyond the elastic strain region to cause deformation greater than the above-mentioned radial deformation.