JPH05117870A - Film forming method for oil well pipe joint - Google Patents
Film forming method for oil well pipe jointInfo
- Publication number
- JPH05117870A JPH05117870A JP28331091A JP28331091A JPH05117870A JP H05117870 A JPH05117870 A JP H05117870A JP 28331091 A JP28331091 A JP 28331091A JP 28331091 A JP28331091 A JP 28331091A JP H05117870 A JPH05117870 A JP H05117870A
- Authority
- JP
- Japan
- Prior art keywords
- oil well
- well pipe
- pipe joint
- phosphate
- chemical conversion
- 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.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、油井管継手の表面に耐
焼付性および耐摩耗性にすぐれた被膜を形成する方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating having excellent seizure resistance and wear resistance on the surface of an oil well pipe joint.
【０００２】[0002]
【従来の技術】通常、石油の掘削に用いられる油井管
は、カップリングを介して相互に接続されているが、管
の端部に形成した雄ネジにカップリングの内面に形成し
た雌ネジ部を嵌め合わせ、これらのネジを締め付けるこ
とにより、気密性および液密性を維持して複数の管が接
続される。ところが、この締め付け時にネジ部に大きな
トルクが働くため、ネジ面にゴーリング（かじり疵）な
どの欠陥が生じ易い。そのため、管の繰り返し使用可能
な回数が低下する。また、継手部に腐食が発生すると、
十分な気密性および液密性を確保することができないこ
とになる。2. Description of the Related Art Normally, oil well pipes used for oil drilling are connected to each other through a coupling. However, a male screw formed on the end of the pipe and a female screw formed on the inner surface of the coupling. By fitting and tightening these screws, a plurality of pipes are connected while maintaining air tightness and liquid tightness. However, since a large torque acts on the threaded portion during this tightening, defects such as galling (galling flaw) are likely to occur on the threaded surface. Therefore, the number of times the pipe can be used repeatedly decreases. Also, if corrosion occurs in the joint,
It will not be possible to ensure sufficient air tightness and liquid tightness.
【０００３】このようなゴーリングを防止する方策とし
て、ネジ部表面にリン酸亜鉛の被膜を形成させる方法や
リン酸マンガン被膜を形成する方法（たとえば特開平１
−219173号公報参照）などが提案されている。As a measure to prevent such galling, a method of forming a zinc phosphate coating on the surface of the screw portion or a method of forming a manganese phosphate coating (see, for example, Japanese Patent Laid-Open No. HEI-1)
-219173 gazette) etc. are proposed.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、前者の
リン酸亜鉛の被膜の場合は、膜厚を薄くして初期の効果
を得るために微細な結晶粒としてネジ面に形成させるた
め、ネジ面を脱脂，水洗した後で亜鉛−マンガン−リン
酸塩系の化成処理液で処理して結晶析出の核を形成させ
る表面調整を行い、単位面積当たり多量のリン酸塩結晶
核を析出させると、これによって結晶の成長が阻害され
てリン酸亜鉛被膜が薄く形成されるのであるが、油井管
に耐食性を向上させる目的で１％程度のCrを含有する材
料を用いる場合は、そのネジ面にリン酸亜鉛被覆を形成
することが極めて困難であるという問題がある。However, in the case of the former zinc phosphate coating, in order to reduce the film thickness and form fine crystal grains on the screw surface to obtain the initial effect, the screw surface is After degreasing and washing with water, a zinc-manganese-phosphate-based chemical conversion treatment liquid is applied for surface adjustment to form nuclei for crystal precipitation, and a large amount of phosphate crystal nuclei are precipitated per unit area. Crystal growth is hindered by this, and a zinc phosphate coating is formed thinly. However, when a material containing about 1% Cr is used for the oil country tubular goods to improve corrosion resistance, the phosphate surface is There is the problem that it is extremely difficult to form a zinc coating.
【０００５】一方、後者のリン酸マンガン被膜の場合
は、ネジ面を脱脂,水洗した後でフッ素イオンを0.2 〜
1.6 g/l 添加したマンガン−リン酸塩系の化成処理液で
処理して、結晶粒度が大きくかつ素材に対する付着強度
の高いリン酸マンガン被膜を形成するようにしたもので
あるが、１％Cr鋼の材料を用いる場合は、そのネジ面に
リン酸マンガン被膜を形成することがやはり困難であ
る。On the other hand, in the case of the latter manganese phosphate coating, after degreasing the screw surface and washing with water, fluorine ions are added to 0.2-
It is treated with a manganese-phosphate chemical conversion treatment solution containing 1.6 g / l to form a manganese phosphate coating with a large grain size and high adhesion strength to the material. When using a steel material, it is still difficult to form a manganese phosphate coating on the screw surface.
【０００６】このようなCr含有鋼へ対応する方策とし
て、化成処理時間を長くすること、化成処理の温度
を高めることなどが考えられる。しかし、の場合は当
然のことながらラインの生産性が低下する問題があり、
またでは配管内のスラッジ形成速度が上がってスラッ
ジの堆積量が増加するため配管のメンテナンス量が増加
するという欠点があるなどいずれも大きな問題がある。As a measure to cope with such Cr-containing steel, it is conceivable to prolong the chemical conversion treatment time and increase the chemical conversion treatment temperature. However, of course, there is a problem that the productivity of the line decreases,
In addition, there is a problem that the sludge formation rate in the pipe increases and the amount of sludge accumulated increases, so that the maintenance amount of the pipe increases.
【０００７】本発明は、上記のような従来技術の有する
課題を解決すべくしてなされたものであって、Cr含有鋼
で製造された油井管であってもゴーリングの発生を抑制
することの可能な被膜形成方法を提供することを目的と
する。The present invention has been made in order to solve the above problems of the prior art, and it is possible to suppress the occurrence of galling even in an oil country tubular good made of Cr-containing steel. An object of the present invention is to provide a method for forming a film.
【０００８】[0008]
【課題を解決するための手段】本発明は、Cr含有鋼で製
造された油井管継手に設けられるネジ継手部の表面をリ
ン酸塩系の溶液を用いて化成処理を施す際に、予め前記
ネジ継手部の表面に平均粗さ20〜60μm の凹凸加工を施
すことを特徴とする油井管継手の被膜形成方法である。Means for Solving the Problems According to the present invention, when the surface of a screw joint portion provided in an oil well pipe joint made of Cr-containing steel is subjected to chemical conversion treatment using a phosphate-based solution, A method for forming a coating film on an oil country tubular goods joint, which comprises subjecting the surface of the threaded joint to an unevenness having an average roughness of 20 to 60 µm.
【０００９】[0009]
【作 用】本発明によれば、油井管にCr含有鋼の材質を
用いる場合に、そのネジ面をブラスティング処理を行っ
て平均粗さＲa が20〜60μm の凹凸を付けてその表面積
を大きくしてからリン酸塩系の溶液で化成処理するよう
にしたので、リン酸塩系の被膜を短時間で効果的に形成
することが可能である。[Operation] According to the present invention, when a material containing Cr-containing steel is used for the oil country tubular goods, its threaded surface is subjected to blasting treatment to form irregularities having an average roughness Ra of 20 to 60 μm to increase its surface area. After that, the chemical conversion treatment is performed with the phosphate-based solution, so that the phosphate-based coating can be effectively formed in a short time.
【００１０】ここで、平均粗さＲa が20〜60μm である
理由について説明すると、平均粗さＲa が20μm よりも
小さいと、被覆形成されるべき面の表面積が小さくなっ
てトータルの化成量が不足するため、リン酸塩の膜厚が
厚くならないから20μm 以上とする必要があり、また60
μm よりも大きいと、表面に加工硬化層が生じ始めて
逆にリン酸塩が形成されない、ネジの寸法公差からネ
ジ寸法が外れてしまうなどの問題があるからである。The reason why the average roughness Ra is 20 to 60 μm is explained below. When the average roughness Ra is smaller than 20 μm, the surface area of the surface to be coated is small and the total chemical conversion is insufficient. Therefore, it is necessary to set the thickness of the phosphate to 20 μm or more because it does not become thick.
If it is larger than μm, a work-hardened layer will start to be formed on the surface, phosphate will not be formed, and there will be problems such as deviation from the screw size tolerance.
【００１１】なお、ブラスティング処理に用いる研掃材
としては、ブラスティング時にネジ面を加工硬化させに
くいたとえばサンドやアルミナなどの材料が望ましく、
その粒径は0.5 〜３mmφ程度が適当である。また、ネジ
面に形成するリン酸塩被膜厚さは、10回の締め付け・締
め戻しに十分耐え得るためには10μm 以上の値であれば
よい。It should be noted that the polishing agent used for the blasting treatment is preferably a material such as sand or alumina which is difficult to work harden the screw surface during blasting.
It is suitable that the particle size is about 0.5 to 3 mmφ. Further, the phosphate film thickness formed on the screw surface may be a value of 10 μm or more in order to sufficiently withstand tightening and unfastening 10 times.
【００１２】[0012]
【実施例】以下に、本発明の実施例について説明する。
0.25wt％Ｃ−0.8 wt％Cr鋼で耐サワー用として製造した
油井管のネジ面を予めサンドブラストで平均40μm に加
工したのち、88℃に加熱した亜鉛−マンガン−リン酸塩
系の化成処理液で処理した。そのときのリン酸亜鉛被膜
厚さの時間的推移を図１に示した。なお、比較のため
に、同一材質の油井管ネジ面をネジ切りのままのブラス
ティングしない状態で同一条件で化成処理したのを比較
例Ｉとして、またCrを含有しない従来の0.25wt％Ｃ鋼の
を比較例IIとして、それぞれ図１に併せて示した。EXAMPLES Examples of the present invention will be described below.
A zinc-manganese-phosphate type chemical conversion treatment solution in which the threaded surface of an oil country tubular good made of 0.25 wt% C-0.8 wt% Cr steel for sour resistance was beforehand sandblasted to an average of 40 μm and then heated to 88 ° C. Processed in. The time course of the zinc phosphate coating thickness at that time is shown in FIG. For comparison, as a comparative example I, a chemical conversion treatment was performed under the same conditions on the threaded surface of an oil country tubular goods made of the same material without being blasted as is, and a conventional 0.25 wt% C steel containing no Cr. Is also shown in FIG. 1 as Comparative Example II.
【００１３】この図から明らかなように、本発明例は化
成処理時間が３分以上においては、10μm 以上の厚さの
リン酸亜鉛被膜を得ることができ、比較例Ｉに比してそ
の被膜厚さがほぼ30％以上厚いものが得られることがわ
かる。ただし、比較例IIと比べると、本発明例のリン酸
亜鉛被膜は逆に30％程度薄目であるが、この差は明らか
にCr含有による影響が出たものである。なお、化成処理
液として、マンガン−リン酸塩系を用いるようにしても
同様の作用効果を得ることができることはいうまでもな
い。As is apparent from this figure, in the case of the present invention, a zinc phosphate coating having a thickness of 10 μm or more can be obtained when the chemical conversion treatment time is 3 minutes or more. It can be seen that a thickness of about 30% or more can be obtained. However, compared with Comparative Example II, the zinc phosphate coating of the present invention example is about 30% thinner, but this difference is clearly influenced by the Cr content. Needless to say, even if a manganese-phosphate system is used as the chemical conversion treatment liquid, the same effects can be obtained.
【００１４】[0014]
【発明の効果】以上説明したように本発明によれば、ネ
ジ面に化成処理を施す前に予めブラスティング処理を行
うようにしたので、短時間で所定の厚さのリン酸被膜を
得ることが可能となり、これによって、継手部を締め付
けした際にゴーリングの発生を抑制することができるか
ら、ネジ品質の向上に寄与すること大である。As described above, according to the present invention, the blasting treatment is carried out in advance before the chemical conversion treatment is applied to the screw surface, so that the phosphoric acid film having a predetermined thickness can be obtained in a short time. This makes it possible to suppress the occurrence of goring when the joint portion is tightened, which greatly contributes to the improvement of the screw quality.
【図１】本発明方法を適用したときのリン酸亜鉛被膜厚
さの時間的推移を示す特性図である。FIG. 1 is a characteristic diagram showing a temporal transition of a zinc phosphate coating thickness when a method of the present invention is applied.
Claims (1)
けられるネジ継手部の表面をリン酸塩系の溶液を用いて
化成処理を施す際に、予め前記ネジ継手部の表面に平均
粗さ20〜60μm の凹凸加工を施すことを特徴とする油井
管継手の被膜形成方法。1. When the surface of the threaded joint portion provided in an oil well pipe fitting made of Cr-containing steel is subjected to chemical conversion treatment using a phosphate-based solution, the surface of the threaded joint portion is preliminarily subjected to an average roughness. A method for forming a coating film on an oil well pipe fitting, which comprises subjecting an unevenness of 20 to 60 μm to a surface treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28331091A JPH05117870A (en) | 1991-10-29 | 1991-10-29 | Film forming method for oil well pipe joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28331091A JPH05117870A (en) | 1991-10-29 | 1991-10-29 | Film forming method for oil well pipe joint |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05117870A true JPH05117870A (en) | 1993-05-14 |
Family
ID=17663806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28331091A Pending JPH05117870A (en) | 1991-10-29 | 1991-10-29 | Film forming method for oil well pipe joint |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05117870A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6027145A (en) * | 1994-10-04 | 2000-02-22 | Nippon Steel Corporation | Joint for steel pipe having high galling resistance and surface treatment method thereof |
| JP2001335956A (en) * | 2000-05-23 | 2001-12-07 | Nippon Steel Corp | MANGANESE PHOSPHATE CHEMICAL CONVERSION TREATING METHOD FOR OIL WELL TUBE JOINT MADE OF Cr-CONTAINING STEEL |
| WO2005098300A1 (en) | 2004-04-06 | 2005-10-20 | Sumitomo Metal Industries, Ltd. | Threaded joint for steel pipe and process for producing the same |
| JP2008540961A (en) * | 2005-05-13 | 2008-11-20 | ハイドリル・エルエルシー | Novel processing method and design method for pipe joint |
| US7666266B2 (en) | 2003-12-04 | 2010-02-23 | Sumitomo Metal Industries, Ltd. | Surface conditioning prior to chemical conversion treatment of a steel member |
-
1991
- 1991-10-29 JP JP28331091A patent/JPH05117870A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6027145A (en) * | 1994-10-04 | 2000-02-22 | Nippon Steel Corporation | Joint for steel pipe having high galling resistance and surface treatment method thereof |
| JP2001335956A (en) * | 2000-05-23 | 2001-12-07 | Nippon Steel Corp | MANGANESE PHOSPHATE CHEMICAL CONVERSION TREATING METHOD FOR OIL WELL TUBE JOINT MADE OF Cr-CONTAINING STEEL |
| US7666266B2 (en) | 2003-12-04 | 2010-02-23 | Sumitomo Metal Industries, Ltd. | Surface conditioning prior to chemical conversion treatment of a steel member |
| WO2005098300A1 (en) | 2004-04-06 | 2005-10-20 | Sumitomo Metal Industries, Ltd. | Threaded joint for steel pipe and process for producing the same |
| US7866706B2 (en) | 2004-04-06 | 2011-01-11 | Sumitomo Metal Industries, Ltd. | Threaded joint for steel pipe |
| JP2008540961A (en) * | 2005-05-13 | 2008-11-20 | ハイドリル・エルエルシー | Novel processing method and design method for pipe joint |
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