【発明の詳細な説明】〈産業上の利用分野〉 開示技術は、スラリー輸送配管、空気輸送配管
等に用いる耐摩耗性の二重管の製造の技術分野に
属する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to the technical field of manufacturing wear-resistant double pipes used for slurry transport piping, pneumatic transport piping, etc.
〈用語の説明〉 この出願の発明では、内外管について、重層と
は内外管の両管を軸芯を合わせて組み合わせるこ
とを示し、外管を内管に外挿、或いは、内管を外
管に内挿した状態を意味し、相対重層とは外管を
固定し、内管を挿入すること、もしくは、内管を
固定し、外管を挿入すること、もしくは、これら
の組み合せによる重層の意味である。<Explanation of terminology> In the invention of this application, regarding the inner and outer tubes, "multilayer" refers to combining both the inner and outer tubes with their axes aligned, and the outer tube is inserted into the inner tube, or the inner tube is inserted into the outer tube. Relative layering means fixing the outer tube and inserting the inner tube, fixing the inner tube and inserting the outer tube, or layering by a combination of these. It is.
又、嵌合とは内外管の嵌め合いを示し、嵌合代
は両管の緊結の際の当該嵌め合い代を示す物理量
である。 Furthermore, the term "fitting" refers to the fitting of the inner and outer tubes, and the fitting distance is a physical quantity indicating the fitting distance when the two tubes are fastened together.
〈要旨の概要〉 而して、この出願の発明は低炭素鋼管等の高靱
性の外管に対し、高炭素鋼管等の高硬度の内管を
重層させた後機械的、或いは、熱的手段により嵌
合代を介して自緊させるようにした耐摩耗二重管
の製造方法に関する発明であり、特に、上記高炭
素鋼管等の内管の降伏点が低く、高靱性を有する
外管に対し、焼入状態では降伏点が高く、高硬度
の材料よりなる高炭素鋼管等の内管を焼純状態に
して相対重層させ、塑性変形を伴なう内管の拡
径、或は、外管の縮径を付与することにより内外
管を密着させ、その状態で少くとも内管を焼入さ
せることにより、該内管を硬化させて耐摩耗性を
付与すると共にマンテンサイト変態による膨脹に
より、内管を増径して両管を嵌合緊着させ、更に
は内管に対する焼入により該内管の降伏点を上昇
させたうえで少くとも外管の弾性限度以上に内外
両管を一体的に縮径させてその弾性戻り差を利用
して大きな嵌合代を得て、自緊させるようにした
耐摩耗二重管の製造方法に係る発明である。<Summary of the gist> The invention of this application consists of layering a high-hardness inner pipe such as a high-carbon steel pipe on a high-toughness outer pipe such as a low-carbon steel pipe, and then applying mechanical or thermal means to the outer pipe. This invention relates to a method of manufacturing a wear-resistant double-pipe tube that is self-tightening through a fitting allowance, and is particularly applicable to an outer tube that has a low yield point and high toughness of the inner tube such as the above-mentioned high carbon steel tube. Inner tubes such as high-carbon steel tubes made of materials with high yield points and high hardness in the quenched state are made to be in a quenched pure state and layered relative to each other, and the diameter of the inner tube is expanded with plastic deformation, or the outer tube is By reducing the diameter of the inner and outer tubes, and quenching at least the inner tube in this state, the inner tube is hardened and wear-resistant, and the inner tube is expanded by mantensite transformation. The diameter of the tube is increased to fit and tighten the two tubes, and the yield point of the inner tube is increased by quenching the inner tube, and the inner and outer tubes are integrated to at least exceed the elastic limit of the outer tube. This invention relates to a method of manufacturing a wear-resistant double-pipe tube that is self-tightening by reducing the diameter and utilizing the difference in elastic return to obtain a large fitting margin.
〈従来の技術〉 周知の如く、配管は流体輸送等に広く利用され
ており、そのうち、例えば、スラリーの輸送、或
いは、粉粒体の空気輸送等に供される配管には内
面に充分な耐摩耗性を具備させておく必要があ
る。<Prior Art> As is well known, piping is widely used for transporting fluids, etc. Among them, for example, piping used for transporting slurry or pneumatic transport of powder and granules has an inner surface with sufficient resistance. It is necessary to have wear resistance.
しかしながら、配管用の鉄鋼材料は一般に硬度
を高めて耐摩耗性を向上させると靱性が低下し、
管が衝撃的な力によつて破壊し易くなる傾向があ
り、実用上からは単層の鋼管では材質的に付与し
得る耐摩耗性にはおのずから限度がある。 However, when steel materials for piping are made harder and wear resistant, their toughness generally decreases.
The pipe tends to be easily broken by impact force, and from a practical point of view, there is a natural limit to the wear resistance that can be imparted to a single-layer steel pipe due to its material.
これに対処するに鋼管に耐摩耗性の高い材料を
内張することにより輸送機能と耐摩耗性機能の複
合機能を付与した二重管が用いられるようになつ
てきている。 To cope with this problem, double-walled pipes are being used, in which a steel pipe is lined with a highly wear-resistant material to provide a combined transport function and a wear-resistant function.
〈発明が解決しようとする課題〉 かかる複合機能を有する二重管の製造には、こ
れまで、例えば、管内面に硬化肉盛を施す方法や
遠心鋳造法により耐摩耗性の高い材料を内張する
方法が用いられてきたが、製造過程で内張材に引
張残留応力を生じるため、外力が印加されると割
れを生じ易く、又、内張材が管と冶金的に接合し
ているため一旦割れを生じると亀裂が止まらない
という欠点があつた。<Problems to be Solved by the Invention> In order to manufacture double-walled pipes having such multiple functions, for example, methods of hardfacing the inner surface of the pipe or centrifugal casting have been used to line the pipe with a highly wear-resistant material. However, since tensile residual stress is generated in the lining material during the manufacturing process, cracking is likely to occur when external force is applied, and because the lining material is metallurgically bonded to the pipe, The drawback was that once cracking occurred, the cracking would not stop.
これに対し、外管に内張材相当の内管を相対重
層して、該内管に液体圧等を印加したり、内径よ
り大きな中子を通して機械的に拡管し、或いは、
焼きばめ式に加熱膨脹した外管に内管を重層後該
外管を冷却して緊結する所謂緊着二重管の製造方
法もあるが、耐摩耗性材料より成る内管は一般に
高強度、低靱性であるため、前者の方法を採用す
るのは困難であり、又、厳しい合わせ精度が必要
とされる後者の方法では長尺管の製作には向かな
い難点があり、実用上の採用は不可能であつた。 On the other hand, by layering an inner tube equivalent to a lining material on the outer tube and applying liquid pressure etc. to the inner tube, or mechanically expanding the tube through a core larger than the inner diameter, or
There is also a method of manufacturing so-called tight double tubes in which an inner tube is layered on an outer tube that has been heated and expanded using a shrink fit method, and then the outer tube is cooled and bonded together, but the inner tube is generally made of a wear-resistant material with high strength. However, it is difficult to use the former method due to its low toughness, and the latter method requires strict alignment accuracy, making it unsuitable for manufacturing long pipes, making it difficult to use in practice. was impossible.
他方、出願人の先願発明である、例えば、特開
昭57−152326号公報発明に示されている如く、内
外管の相対重層の後、加熱後、急冷することによ
り生じるマルテンサイト変態による内管の膨脹を
介して外管と内管を緊結する二重管製造方法があ
る。 On the other hand, as shown in the applicant's earlier invention, for example, the invention disclosed in Japanese Patent Application Laid-Open No. 152326/1983, internal transformation due to martensitic transformation caused by rapid cooling after heating after relative overlapping of the inner and outer tubes. There is a method of manufacturing a double tube in which an outer tube and an inner tube are tightly connected through expansion of the tube.
しかしながら、かかる二重管製造方法では内管
として加工誘起マルテンサイト変態を生じる材質
のものを用い、該加工誘起マルテンサイト変態に
際しての変態膨脹により内外管を緊結させるた
め、特に耐摩耗性に優れた材料を内管とする二重
管の製造に適さないという不都合さがあつた。 However, in this double-pipe manufacturing method, the inner tube is made of a material that undergoes deformation-induced martensitic transformation, and the inner and outer tubes are bonded together by transformation expansion during the deformation-induced martensitic transformation, so that the inner tube has particularly excellent wear resistance. This method has the disadvantage that it is not suitable for manufacturing double-walled pipes using this material as an inner pipe.
〈発明の目的〉 この出願の発明の目的は、より長寿命の耐摩耗
性の配管が望まれているのにもかかわらず、上述
の従来技術ではこれに対処出来ないという問題を
解決すべき技術的課題とし、高靱性の外管と高硬
度の内管とを相対重層し、内管のマルテンサイト
変態に伴う膨脹、或は、内外管の降伏強さの差に
基づく弾性戻り差を利用して嵌合応力を導入し、
高靱性の外管が、高硬度ではあるものの、低靱性
の内管をたが締めすることにより管全体が配管と
して充分な靱性を有するようにして各種産業にお
ける配管技術利用分野に益する優れた耐摩耗二重
管の製造方法を提供せんとするものである。<Object of the Invention> The object of the invention of this application is to provide a technology to solve the problem that the above-mentioned prior art cannot cope with the desire for wear-resistant piping with a longer life. The objective was to layer a highly tough outer tube and a highly hard inner tube in relative layers, and utilize the expansion caused by the martensitic transformation of the inner tube, or the difference in elastic return based on the difference in yield strength between the inner and outer tubes. Introducing mating stress by
Although the highly tough outer tube has high hardness, by tightening the low toughness inner tube, the entire tube has sufficient toughness as piping, which is an excellent product that benefits piping technology applications in various industries. The present invention aims to provide a method for manufacturing a wear-resistant double pipe.
〈課題を解決するための手段・作用〉 上述目的に沿い先述特許請求の範囲を要旨とす
るこの出願の発明の構成は、前述課題を解決する
ために、低い降伏点であつて高靱性を有する材料
から成る外管と、高い降伏点と高硬度を有する材
料から成る内管とを該内管を焼純状態にして機械
的に拡管、又は、縮管する場合にはその荷重−変
位曲線が両管共にほぼ近似し、したがつて、弾性
戻り差が無く、密着可能である性質を利用して相
対重層後の外管と内管の密着状態を現出し、その
後、少くとも内管に対し焼入を行うことにより該
内管の硬度を高めると共にマルテンサイト変態に
伴う膨径により大きな嵌合代を生ぜしめて内外管
が緊結されるようにすることを基幹とし、該内外
管の緊結後、更に、続いて外管の弾性限界以上に
内外管を縮径することにより、弾性戻り差を利用
して内外両管をより強固に緊着嵌合させることが
出来るようにした技術的手段を講じたものであ
る。<Means/effects for solving the problem> In order to solve the above-mentioned problems, the structure of the invention of this application, which is based on the above-mentioned claims, has a low yield point and high toughness. When an outer tube made of a material and an inner tube made of a material with a high yield point and high hardness are expanded or contracted mechanically with the inner tube in a sintered pure state, the load-displacement curve is Both tubes are almost similar, therefore, there is no difference in elastic return, and by utilizing the property that they can be in close contact, the state of close contact between the outer tube and the inner tube after relative overlapping is created, and then at least for the inner tube. The basic idea is to increase the hardness of the inner tube by quenching, and to create a large fitting allowance due to the expansion diameter caused by martensitic transformation, so that the inner and outer tubes are tightened.After tightening the inner and outer tubes, Furthermore, by subsequently reducing the diameter of the inner and outer tubes beyond the elastic limit of the outer tube, a technical measure was taken that made it possible to more firmly fit the inner and outer tubes by utilizing the difference in elastic return. It is something that
〈発明の原理的背景〉 次に、この出願の発明の原理的根拠を説明する
が、高炭素鋼材料には加熱後急速冷却によつてマ
ルテンサイト変態を行うようにすると、その金属
組成により硬度が急速に高まると共に膨脹するも
のがあり、例えば、900℃から100℃までの冷却を
10secより短い時間をかけて行うと、炭素量0.25
％程度の低炭素鋼ではその硬度がビツカース硬さ
で140〜180程度で、硬度や降伏点の著しい上昇は
見られないのに比し、炭素量0.55％程度の高炭素
鋼ではビツカース硬さで400〜800程度まで硬度が
上がり、降伏点も著しく上昇すると共にいく分膨
脹することが分かつている。<Principle Background of the Invention> Next, the principle basis of the invention of this application will be explained. When high carbon steel material undergoes martensitic transformation by rapid cooling after heating, hardness increases due to its metal composition. Some things expand as the temperature increases rapidly; for example, when cooled from 900℃ to 100℃.
If the time is shorter than 10 seconds, the carbon content will be 0.25
Low carbon steel with a carbon content of about 0.55% has a hardness of about 140 to 180 on the Bitkers hardness, and no significant increase in hardness or yield point is observed, whereas high carbon steel with a carbon content of about 0.55% has a hardness of about 140 to 180 on the Bitkers hardness. It is known that the hardness increases to about 400 to 800, the yield point increases significantly, and the material expands to some extent.
そこで、低炭素鋼等の降伏点が低く、高靱性を
有する管を外管とし、高炭素鋼等の高い降伏点と
高硬度の管を内管として使用する場合にその焼入
による内管の増径により外管と内管に大きな嵌合
代を生じさせて緊着させることが出来、同時に少
くとも内管を焼入し、高硬度を付与し、一方、外
管は高靱性を具備していることにより内管をたが
締めして実用的な高硬度二重管を得ることが出来
るものである。 Therefore, if a tube with a low yield point and high toughness such as low carbon steel is used as the outer tube, and a tube with a high yield point and high hardness such as high carbon steel is used as the inner tube, the inner tube will be damaged by quenching. By increasing the diameter, it is possible to create a large fitting allowance between the outer tube and the inner tube, allowing them to be tightly connected.At the same time, at least the inner tube is quenched to give it high hardness, while the outer tube has high toughness. This makes it possible to hoop-tighten the inner tube and obtain a practical double tube with high hardness.
〈実施例〉 次に、この出願の発明の実施例を図面に従つて
説明すると、焼入状態では高い降伏点と高硬度を
有する高炭素鋼製の内管２と、低い降伏点、及
び、高靱性を有する低炭素鋼製の外管１を用い、
該外管１と内管２の初期径差をR1として該内管
２を予め焼純状態にして外管１に相対重層し、第
４図（当該第４図で図示の都合上内外管１，２の
初期径差をR1を示すためデフオルメして間隙の
ある状態を示してある。）に示す様に、外管１の
外側からダイス３により該外管１、及び、内管２
に対し縮径作用を行うように両管１，２を矢印の
方に引き出すと、両管１，２は弾塑性変形して縮
径されるが、横軸に直径の変化量（変位量）Ｒ
（原点に対し左にいく程、直径が小さくなる）を、
縦軸に縮径荷重Ｆ（原点に対し上にいく程、縮径
荷重が大きくなる）をとる第１図に示す様に、内
管２が予め焼純されていることにより、外管１、
及び、内管２の荷重−変位曲線はほぼ近似して弾
性戻り差はなく、したがつて、外管１は点線で示
すイ，ロ，ハの点線で示す経路をたどり、一方、
内管２はイ′，ロ′，ハ′の実線に示す経路をたど
り、（ロ′からハ、及び、ハ′にかけてのグラフの
点線、及び、実線の経路は実際には重なつている
のであるが、図示の関係上、当該第１図では僅か
にずらして示してある。）ダイス３通過後の縮径
作用停止による弾性戻り過程では外管１はハ，ニ
の経路を、又、内管２はハ′，ニ′の経路をとり、
両者の径差R2、即ち、間隙はほぼ０になり、し
たがつて、内管２を予め焼純しておくことによ
り、外管１と内管２には第１段階として第４図右
側に示す密着した素材二重管４とすることが出来
る。<Example> Next, an example of the invention of this application will be described with reference to the drawings. An inner tube 2 made of high carbon steel that has a high yield point and high hardness in a quenched state, a low yield point, and Using an outer tube 1 made of low carbon steel with high toughness,
The initial diameter difference between the outer tube 1 and the inner tube 2 is set toR1 , and the inner tube 2 is sintered in advance and layered on the outer tube 1, as shown in FIG. The initial diameter difference between the outer tube 1 and the inner tube 2 is deformed to show R1 to show a gap.) As shown in FIG.
When both tubes 1 and 2 are pulled out in the direction of the arrow so as to perform a diameter reduction action, both tubes 1 and 2 are deformed elastically and reduced in diameter, but the horizontal axis shows the amount of change in diameter (displacement). R
(The further to the left of the origin, the smaller the diameter).
As shown in FIG. 1, where the diameter reduction load F is plotted on the vertical axis (the diameter reduction load increases as it goes upwards from the origin), the outer tube 1,
And, the load-displacement curve of the inner tube 2 is almost approximate and there is no difference in elastic return, so the outer tube 1 follows the path shown by the dotted lines A, B, and C shown by the dotted lines, while,
The inner tube 2 follows the path shown by the solid lines A', B', and C' (the dotted lines and the solid line paths in the graph from B' to C and C' actually overlap, so However, for convenience of illustration, the outer tube 1 is shown slightly shifted in FIG. Pipe 2 takes the route C', D',
The diameter difference R2 between the two, that is, the gap, becomes almost 0. Therefore, by pre-sintering the inner tube 2, the outer tube 1 and the inner tube 2 are made as shown in the right side of Fig. 4 as a first step. It is possible to form a double-walled tube 4 made of closely-adhered material as shown in FIG.
而して、このようにして得られた素材二重管４
において、次の第２段階として例えば、内側から
図示しない高周波誘導加熱装置による加熱を内管
２に付した後、水冷する手段による内管２に対し
て焼入を付与すると、前述原理的背景の理論によ
り該内管２に対しては高硬度が付与され、且つ、
降伏点が上昇して増径し、第２図に示す様に、内
外管１，２の径差R1′（R1＜R1′とされて両管１，
２は嵌合出来ることになる。 Therefore, the material double tube 4 obtained in this way
In the second step, for example, the inner tube 2 is heated from the inside by a high-frequency induction heating device (not shown), and then the inner tube 2 is hardened by means of water cooling. According to theory, high hardness is imparted to the inner tube 2, and
The yield point rises and the diameter increases, and as shown in Fig. 2, the diameter difference between the inner and outer tubes 1 and 2 is R1 ′ (R1 < R1 ′, and both tubes 1,
2 can be fitted.
これまでのプロセスはこの出願の第１の発明を
成すものである。 The process thus far constitutes the first invention of this application.
而して、内外管１，２に径差R1′を付与する上
述プロセスの後に更にダイス３を外管１の外側か
ら作用させて第二次的に内外両管１，２に対し縮
径作用を与えて内管２にその弾性範囲内で、且
つ、外管１の弾性限界以上に縮径させると、当該
第２図に示す様に、外管１はイ，ロ，ハ、内管は
イ′，ロ′，ハ′の経路をたどり、ダイス３に対す
る相対通過後は縮径作用が開放されて両管１，２
が増径し外管はニ、内管はニ′に至る。 After the above-mentioned process of imparting the diameter difference R1 ' to the inner and outer tubes 1 and 2, the die 3 is further applied from the outside of the outer tube 1 to secondarily reduce the diameter of both the inner and outer tubes 1 and 2. When an action is applied to cause the inner tube 2 to contract within its elastic range and beyond the elastic limit of the outer tube 1, the outer tube 1 becomes A, B, C, and the inner tube as shown in FIG. follows the path A', B', and C', and after passing relative to the die 3, the diameter reducing action is released and both pipes 1 and 2
increases in diameter, and the outer tube reaches d and the inner tube reaches d'.
内外管１，２の初期径差R1′は出来るだけ小さ
いことが望ましいが、径差R2の大きな嵌合代を
得て緊結され、したがつて、内管２に対する外管
１の嵌合分は増大する。 Although it is desirable that the initial diameter difference R1 ′ between the inner and outer tubes 1 and2 is as small as possible, the fitting of the outer tube 1 to the inner tube 2 is difficult because a large fitting margin of the diameter difference R 2 is obtained and the fitting is made tight. minutes will increase.
上述プロセスで経路イ，ロの傾きと経路イ′，
ロ′の傾きはダイス３の相対通過プロセス時で材
質形状が変わらなければ同じであるが、材質形状
（径と肉厚）等が異なる場合は異なることになる。 In the above process, the slopes of paths i and b and paths i′,
The slope of R' remains the same unless the material shape changes during the relative passing process of the die 3, but it will differ if the material shape (diameter and wall thickness) etc. differ.
尚、ΔRはダイス３による外管の縮径代であ
る。 Note that ΔR is the diameter reduction margin of the outer tube by the die 3.
そして、上の如く、外管１の弾性限界以上に第
二次的に縮径が作用するプロセスでは、第３図
（外管１の経路イ，ロ，ハ，ニ、内管２の経路
イ′，ロ′，ハ′，ニ′）に示す様に、縮径代R2は
大きく嵌合分は最も大きく、又、安定して生じる
ので、生産性が高く更に有効であるが、この場
合、内管２を塑性変形させるため、亀裂等の破損
が生じないように制御することが必要である。 As shown above, in the process where the diameter decreases secondarily beyond the elastic limit of the outer tube 1, as shown in FIG. ′, B′, C′, D′), the diameter reduction R2 is large and the fitting portion is the largest, and it occurs stably, so it is highly productive and more effective. Since the inner tube 2 is plastically deformed, it is necessary to control the inner tube 2 so that damage such as cracks does not occur.
上述第１，２図の引き続きのプロセスがこの出
願の第２の発明を示すものであるが、内外管１，
２を密着させるための第一回の縮径と、両管一体
で外管１の弾性限界以上に塑性変形させるための
第二回の縮径とを２度加える必要がある。 The subsequent process shown in FIGS. 1 and 2 above shows the second invention of this application, but the inner and outer tubes 1,
It is necessary to perform the first diameter reduction to bring the outer tubes 2 into close contact with each other, and the second diameter reduction to cause the two tubes to be plastically deformed together beyond the elastic limit of the outer tube 1.
尚、この出願の発明の実施態様は上述実施例に
限るものでないことは勿論であり、例えば、外管
に対し内管を焼純状態で相対重層して両管の荷重
−変位曲線がほぼ近似して弾性戻り差が無いこと
の利用による密着に際しては上述実施例の縮径操
作以外にも塑性拡径を行うようにしても良く、
又、両管密着後の二次縮径に際しての内管に対す
る焼入は外管との一体焼入でも良い等種々の態様
が採用可能である。 The embodiments of the invention of this application are, of course, not limited to the above-mentioned embodiments. For example, the inner tube may be layered relative to the outer tube in a sintered state so that the load-displacement curves of both tubes are approximately similar. In order to achieve close contact by taking advantage of the fact that there is no difference in elastic return, plastic diameter expansion may be performed in addition to the diameter reduction operation in the above embodiment.
In addition, various methods can be adopted for hardening the inner tube during the secondary diameter reduction after the two tubes are brought into close contact with each other, such as integral hardening with the outer tube.
〈発明の効果〉 以上、この出願の発明によれば、基本的に耐摩
耗二重管の製造において、従来の肉盛法や遠心鋳
造法による高価な製造方法によらず、低コストで
耐摩耗性の二重管が出来、外管による内管のたが
締めにより結果的に二重管全体に高靱性も得られ
るという優れた効果が奏され、外管と内管の材料
選択にも大きな自由度が得られ、それにより、例
えば、複数の両端にフランジで付けたユニツト管
を各々のフランジを介して連結する場合、各二重
管の外管にフランジを溶接接合が可能な低炭素鋼
を用いることが出来るので、通常の配管に用いる
フランジが使え、ユニツト管の製造がし易いとい
う優れた効果が奏される。<Effects of the Invention> As described above, according to the invention of this application, wear-resistant double pipes can be basically manufactured at low cost without using expensive manufacturing methods such as the conventional overlay method or centrifugal casting method. By tightening the inner tube with the outer tube, this has the excellent effect of providing high toughness to the entire double tube. Low carbon steel provides a degree of freedom and allows for welding of flanges to the outer tube of each double tube, for example, when connecting multiple unit tubes with flanges on both ends via their respective flanges. Since flanges used for ordinary piping can be used, excellent effects are achieved in that unit pipes can be manufactured easily.
又、外管と内管とが自緊状態であるために、内
管に貫通欠陥が生じても、管全体として内外管が
冶金的に接合されておらず、又、外管が高靱性で
あるために貫通欠陥が生じ難く、二重管の機能が
終始保持されやすいという優れた効果が奏され
る。 In addition, because the outer tube and inner tube are self-tight, even if a penetration defect occurs in the inner tube, the inner and outer tubes are not metallurgically joined as a whole, and the outer tube has high toughness. Because of this, penetration defects are less likely to occur, and the double pipe function is easily maintained from beginning to end, which is an excellent effect.
又、長尺管の製造に際しても、ダイス等による
縮径は長さに関係なく行えるために、その製造が
し易いという優れた効果があり、液圧拡管法等に
よる場合に比して内管の肉厚に拘束されないとい
う自由さがあり、ダイス等による縮径の際にも大
きな力を必要とせず、動力費も節減され、結果的
に低コストが図れるという効果も奏される。 In addition, when manufacturing long pipes, diameter reduction using dies etc. can be performed regardless of the length, which has the excellent effect of making it easier to manufacture, and the inner pipe size is smaller than when using hydraulic pipe expansion methods. It has the freedom of not being restricted by the wall thickness, and does not require a large force when reducing the diameter using a die, etc., and the power cost is also reduced, resulting in the effect of lowering costs.
而して、外管に低い降伏点の材料の管を用いる
ことにより、又、内管に焼入状態では高い降伏点
を有する管を用いたことにより、初期の外管に対
する内管の相対重層時に該内管を焼純状態にする
ことで両者の応力歪曲線をほぼ近似させて弾性戻
り差を無くすことが出来、そのため、両管の密着
を可能にすることが出来、第一次の縮径に続く第
二次の縮径の際に内管に対する焼入付与を介して
マルテンサイト変態時の内管の高硬度付与と共に
その膨脹をより効果的に利用することによつて嵌
合代を大きくし、この出願の第２の発明に示す如
く強く自緊を得ることが出来る優れた効果が奏さ
れる。 By using a tube made of a material with a low yield point for the outer tube, and by using a tube that has a high yield point in the quenched state for the inner tube, the initial relative stacking of the inner tube with respect to the outer tube is improved. Sometimes, by making the inner tube into a sintered state, the stress strain curves of the two can be approximated and the difference in elastic return can be eliminated. Therefore, it is possible to make the two tubes come into close contact, and the first shrinkage can be reduced. During the second diameter reduction that follows the diameter, the inner tube is hardened and hardened during martensitic transformation, and the expansion is used more effectively to reduce the fitting allowance. As shown in the second invention of this application, an excellent effect can be obtained in which a strong self-constriction can be obtained.
図面はこの出願の発明の実施例の説明図であ
り、第１図は外管に対する内管の相対重層時の密
着時の特性グラフ図、第２，３図は二次縮径時の
外管と内管の嵌合代付与の特性図、第４図は縮径
プロセスの断面図である。 １……外管、２……内管、４……二重管。 The drawings are explanatory diagrams of the embodiments of the invention of this application. Fig. 1 is a characteristic graph when the inner pipe is in close contact with the outer pipe in relative overlapping, and Figs. 2 and 3 are graphs of the outer pipe during secondary diameter reduction. FIG. 4 is a characteristic diagram of the fitting allowance provided to the inner tube, and a cross-sectional view of the diameter reduction process. 1...outer tube, 2...inner tube, 4...double tube.
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12266185AJPS61283414A (en) | 1985-06-07 | 1985-06-07 | Manufacture of wear resistant double pipe |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12266185AJPS61283414A (en) | 1985-06-07 | 1985-06-07 | Manufacture of wear resistant double pipe |
| Publication Number | Publication Date |
|---|---|
| JPS61283414A JPS61283414A (en) | 1986-12-13 |
| JPH0586299B2true JPH0586299B2 (en) | 1993-12-10 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12266185AGrantedJPS61283414A (en) | 1985-06-07 | 1985-06-07 | Manufacture of wear resistant double pipe |
| Country | Link |
|---|---|
| JP (1) | JPS61283414A (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5796516B2 (en)* | 2011-03-03 | 2015-10-21 | 新日鐵住金株式会社 | Metal double pipe manufacturing method |
| Publication number | Publication date |
|---|---|
| JPS61283414A (en) | 1986-12-13 |
| Publication | Publication Date | Title |
|---|---|---|
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