JPH0976011A - Method for heat treatment for thickening work of metallic tube and device therefor - Google Patents

Method for heat treatment for thickening work of metallic tube and device therefor

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Publication number
JPH0976011A
JPH0976011A JP25729095A JP25729095A JPH0976011A JP H0976011 A JPH0976011 A JP H0976011A JP 25729095 A JP25729095 A JP 25729095A JP 25729095 A JP25729095 A JP 25729095A JP H0976011 A JPH0976011 A JP H0976011A
Authority
JP
Japan
Prior art keywords
heat treatment
thickness
die
thickening
heating
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
Application number
JP25729095A
Other languages
Japanese (ja)
Other versions
JP2999698B2 (en
Inventor
Yasuo Watanabe
康男 渡辺
Toshio Nagano
敏雄 永野
Tsugio Minagawa
次夫 皆川
Akira Fukuda
章 福田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daiwa House Industry Co Ltd
Dai Ichi High Frequency Co Ltd
Original Assignee
Daiwa House Industry Co Ltd
Dai Ichi High Frequency Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Daiwa House Industry Co Ltd, Dai Ichi High Frequency Co Ltd filed Critical Daiwa House Industry Co Ltd
Priority to JP25729095A priority Critical patent/JP2999698B2/en
Publication of JPH0976011A publication Critical patent/JPH0976011A/en
Application granted granted Critical
Publication of JP2999698B2 publication Critical patent/JP2999698B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PROBLEM TO BE SOLVED: To prevent deformation generated n the cross section of thick part formed at the time of executing local thickening work and heat treatment to a metallic tube such as a square tube. SOLUTION: By preliminarily setting a die 10 for heat treatment in the square tube 1 to be thickened, forming a heated part 5 by locally heating the square tube with a heating device 4 under the state where compressive force is added to the square tube 1 with a compressing device 3 and moving the heated part 5 in the longitudinal direction to the square tube, thick part 1A thickened is continuously formed, the heated part 26 for heat treatment is formed by heating the thick part 1A with an auxiliary heating device 9 and heat treatment of the whole thick part is executed by moving the heated part 26 for heat treatment in the longitudinal direction of the thick part. At the time of these thickening work and heat treatment, deformation on the verge of generating in the thick part 1A is prevented with the die 10 for heat treatment which is set inside the square tube 1 and the thick part 1A having a good cross-sectional shape is formed.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【発明の属する技術分野】本発明は、角形鋼管、丸形鋼
管等の金属管の長手方向の所望区間を増肉させて厚肉部
を形成し且つその厚肉部を熱処理する金属管の増肉加工
熱処理方法及びその方法の実施に用いる金属管の増肉加
工熱処理装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an increase in a metal pipe such as a square steel pipe or a round steel pipe, in which a desired section in the longitudinal direction is thickened to form a thick portion, and the thick portion is heat-treated. The present invention relates to a meat processing heat treatment method and a metal pipe thickening processing heat treatment apparatus used for carrying out the method.

【0002】[0002]

【従来の技術】従来、鋼管等の金属管の長手方向の小領
域を局部的に一定幅に加熱して加熱部を形成し、該加熱
部の位置を管の長手方向に相対的に移動させながら管軸
方向に圧縮力を付与して増肉させ、前記加熱部の後端部
分を冷却して固化することにより、金属管を長手方向に
沿って順次増肉させて行く増肉加工方法(フリー増肉
法)が知られている(例えば、特公昭52−470号公
報参照)。従って、この増肉方法を用いることにより、
金属管の所望領域を増肉させて金属管に一体化した厚肉
の補強部即ち厚肉部を形成でき、そのような厚肉部を有
する金属管を建築資材として使用することが考えられ
る。この厚肉部を一体に有する金属管を建築資材として
使用すると、その厚肉部を梁接合等に使用でき、従来行
われていたダイアフラムの溶接などの面倒な補強工作を
省略することができ、大きなメリットがもたらされる。
2. Description of the Related Art Conventionally, a small region in the longitudinal direction of a metal pipe such as a steel pipe is locally heated to a constant width to form a heating unit, and the position of the heating unit is relatively moved in the longitudinal direction of the pipe. While applying a compressive force in the axial direction of the pipe to increase the thickness, and cooling and solidifying the rear end portion of the heating portion, the metal pipe is gradually increased in thickness along the longitudinal direction. The free thickening method) is known (see, for example, Japanese Patent Publication No. 52-470). Therefore, by using this thickening method,
It is possible to increase the thickness of a desired region of the metal pipe to form a thick reinforcing portion, that is, a thick portion integrated with the metal pipe, and to use the metal pipe having such a thick portion as a building material. By using the metal pipe integrally having this thick wall portion as a building material, the thick wall portion can be used for beam joining, etc., and it is possible to omit troublesome reinforcement work such as welding of the diaphragm which has been conventionally performed. It brings great benefits.

【0003】[0003]

【発明が解決しようとする課題】ところが、上記した増
肉加工方法で形成した厚肉部は、高温に加熱された後、
急冷されるため、焼入れされた状態となり、伸び等の機
械的特性が低下するという問題があった。そこで、厚肉
部を再度加熱して熱処理を行い、機械的特性を改善する
ことが考えられるが、厚肉部の加熱、冷却による熱処理
時に、増肉加工時の残留応力等によって厚肉部にゆがみ
が生じ、問題となることが判明した。例えば、上記した
増肉加工及び熱処理を円形管に対して行うと、厚肉部の
断面形状が円形からゆがんで真円度が低下し、また角形
管に対して行うと、厚肉部の平坦な管壁に内側への凹み
を生じ、平坦度が低下するという現象の生じることが判
明した。このようなゆがみは、特に角形管において顕著
に生じ、重大な問題となった。
However, the thick-walled portion formed by the above-described thickening processing method, after being heated to a high temperature,
Since it is rapidly cooled, it becomes a quenched state, and there is a problem that mechanical properties such as elongation deteriorate. Therefore, it is conceivable to heat the thick-walled part again to heat-treat it to improve the mechanical properties.However, when heat-treating the thick-walled part by heating or cooling, the thick-walled part may be changed due to residual stress during thickening. Distortion occurred and was found to be a problem. For example, when the above-mentioned thickening and heat treatment are performed on a circular pipe, the circularity of the cross section of the thick wall portion is distorted from a circular shape, and the roundness is reduced. It was found that a phenomenon in which a flat tube surface is lowered due to an inward depression on a smooth tube wall. Such distortion is particularly noticeable in a prismatic tube, which is a serious problem.

【0004】本発明は、かかる問題点に鑑みて為された
もので、金属管の長手方向の所望の領域を、断面におけ
る望ましくないゆがみを防止しながら、増肉加工及び熱
処理して断面形状の良好な厚肉部を形成することの可能
な金属管の増肉加工熱処理方法及びそれに使用する装置
を提供することを目的とする。
The present invention has been made in view of the above problems, and a desired region in the longitudinal direction of a metal pipe is subjected to thickening processing and heat treatment while preventing undesired distortion in the cross section, and thus the cross-sectional shape is improved. An object of the present invention is to provide a method of heat treatment for increasing the thickness of a metal tube capable of forming a good thick portion and an apparatus used for the method.

【0005】[0005]

【課題を解決するための手段】上記目的を達成すべくな
された本発明の金属管の増肉加工熱処理方法は、増肉加
工すべき金属管内に、増肉加工によって形成される厚肉
部の内側に位置するように、その厚肉部の長さ以上の長
さを有する熱処理用ダイスをあらかじめ挿入しておき、
この状態で、前記金属管の長手方向の小領域を加熱装置
で局部的に加熱して赤熱状態の加熱部を形成し、該加熱
部を金属管の長手方向に相対的に移動させながら該加熱
部に金属管の長手方向の圧縮力を付与して順次増肉さ
せ、且つ前記加熱部の後端部分を増肉直後に冷却するこ
とによって、金属管を連続的に増肉させて、前記熱処理
用ダイスの外側に厚肉部を形成し、その後、その厚肉部
の内側に熱処理用ダイスを位置させた状態で前記厚肉部
を熱処理することを特徴とするものである。
SUMMARY OF THE INVENTION A metal pipe thickening heat treatment method of the present invention, which has been made to achieve the above object, provides a metal pipe to be thickened in a thick portion formed by the thickening process. To be located inside, insert a heat treatment die having a length equal to or greater than the length of the thick portion in advance,
In this state, a small area in the longitudinal direction of the metal tube is locally heated by a heating device to form a heating section in a red heat state, and the heating section is heated while moving the heating section relatively in the longitudinal direction of the metal tube. By applying compressive force in the longitudinal direction of the metal pipe to the portion to successively increase the thickness, and by cooling the rear end portion of the heating unit immediately after the thickness increase, the metal pipe is continuously increased in thickness and the heat treatment is performed. A thick part is formed on the outside of the die for heat treatment, and then the thick part is heat-treated while the heat treatment die is positioned inside the thick part.

【0006】ここで、厚肉部の熱処理を行うには、その
厚肉部全体を同時に所望温度に加熱して熱処理を行って
もよいが、増肉加工と同様に、厚肉部の小領域を補助加
熱装置によって、所望の熱処理温度に加熱して熱処理加
熱部を形成し、該熱処理加熱部を厚肉部の長手方向に相
対的に移動させることにより、厚肉部の全体を加熱して
熱処理する方法を採用することが好ましい。この方法で
は、比較的小型の補助加熱装置によって厚肉部を所望温
度に加熱可能である。また、その熱処理動作を増肉加工
と並行して行うことが、生産性を向上させるので好まし
い。
Here, in order to heat-treat the thick-walled portion, the entire thick-walled portion may be simultaneously heated to a desired temperature to be heat-treated, but like the thickening process, a small region of the thick-walled portion is required. Is heated to a desired heat treatment temperature by an auxiliary heating device to form a heat treatment heating part, and the heat treatment heating part is relatively moved in the longitudinal direction of the thick part to heat the entire thick part. It is preferable to adopt a method of heat treatment. In this method, the thick portion can be heated to a desired temperature by a relatively small auxiliary heating device. In addition, it is preferable to perform the heat treatment operation in parallel with the thickness increasing process because the productivity is improved.

【0007】上記の構成になる本発明方法では、増肉加
工によって熱処理用ダイスの外側に厚肉部を形成し、そ
の状態で厚肉部の熱処理を行っているので、熱処理時の
加熱、冷却によって厚肉部の断面にゆがみが生じようと
しても、厚肉部内面を熱処理用ダイスが拘束して望まし
くないゆがみを防止でき、このため、所定の断面形状の
且つ熱処理された厚肉部を形成できる。また、熱処理時
のゆがみを熱処理用ダイスによって強制的に防止できる
ため、熱処理時における加熱速度、冷却速度等を調整し
てゆがみの防止を図る必要がなく、換言すれば、加熱速
度、冷却速度等を必要な熱処理を行うことができるよう
に設定できる。
In the method of the present invention having the above-mentioned structure, since the thick portion is formed on the outside of the heat treatment die by the thickening process and the thick portion is heat treated in that state, heating and cooling during the heat treatment are performed. Even if the cross-section of the thick-walled portion is distorted, the heat-treating die restrains the inner surface of the thick-walled portion to prevent undesired distortion. Therefore, the heat-treated thick-walled portion having a predetermined cross-sectional shape is formed. it can. Further, since distortion during heat treatment can be forcibly prevented by the heat treatment die, there is no need to adjust the heating rate, cooling rate, etc. during heat treatment to prevent distortion, in other words, heating rate, cooling rate, etc. Can be set so that the necessary heat treatment can be performed.

【0008】更に、熱処理用ダイスは金属管に増肉加工
を施す前に挿入しているので、挿入時には金属管との間
に適当な間隙が生じており、このため、容易に所定位置
に挿入可能である。しかも、その熱処理用ダイスは、増
肉加工時における断面形状のゆがみを防止する作用を有
しており、この点からも断面形状の良好な厚肉部の形成
を可能としている。更に、熱処理用ダイスは、増肉を生
じている部分に生じやすい不安定な変形(例えば、じゃ
ばら状の変形)を防止し、増肉加工を安定させる作用も
有しており、このため、良好な増肉加工を可能とする増
肉加工条件(例えば、加熱部の温度、圧縮力、冷却速
度、増肉加工速度等)の範囲を広げることができ、増肉
加工速度を上げて生産性を向上させるとか、増肉率を大
きく設定できるとか、増肉加工温度を低く設定して、省
エネを図ることができる等の効果を奏する。
Further, since the heat treatment die is inserted before the metal pipe is subjected to the thickening process, an appropriate gap is formed between the heat treatment die and the metal pipe, and therefore the die is easily inserted at a predetermined position. It is possible. Moreover, the heat treatment die has an effect of preventing the cross-sectional shape from being distorted during the thickening process, and also from this point, it is possible to form a thick wall portion having a good cross-sectional shape. Further, the heat treatment die has an action of preventing unstable deformation (for example, a bellows-like deformation) which is likely to occur in the portion where the thickness increase occurs, and stabilizing the thickness increase process. It is possible to increase the range of thickening conditions (for example, temperature of heating part, compression force, cooling speed, thickening processing speed, etc.) that enables various thickening processing, and increase the thickening processing speed to improve productivity. There are effects such as energy saving and the like, by improving, by setting a large thickness increase rate, and by setting a low temperature for thickening processing.

【0009】ここで、熱処理用ダイスの外形寸法として
は、増肉加工によって形成された厚肉部の内面を熱処理
時に過度のゆがみを生じないように拘束しうるものであ
ればよく、例えば、熱処理用ダイスの外面が厚肉部の内
面に強く接触してその厚肉部を支持した状態とするもの
であってもよいし、或いは、熱処理用ダイスの外面が厚
肉部の内面にほぼ接触した状態、即ち両者が軽く接触す
るか、両者間に微小な(例えば0.5mm程度)の隙間
が生じた状態とするものであってもよい。なお、後者の
寸法としておくと、熱処理後に熱処理用ダイスを引き抜
く動作が容易となる利点が得られる。
Here, the outer dimension of the heat treatment die may be any as long as it can restrain the inner surface of the thick portion formed by the thickening process so as not to cause excessive distortion during the heat treatment. The outer surface of the die for heat treatment may strongly contact the inner surface of the thick portion to support the thick portion, or the outer surface of the heat treatment die may substantially contact the inner surface of the thick portion. It may be in a state where they are lightly contacted with each other or a minute gap (for example, about 0.5 mm) is formed between them. It should be noted that the latter dimension has an advantage that the operation of pulling out the heat treatment die after the heat treatment becomes easy.

【0010】熱処理用ダイスを厚肉部の内面に対してほ
ぼ接触する状態とするには、熱処理用ダイスを増肉加工
前の金属管に挿入した状態での両者の間隙gを、増肉前
の管壁の肉厚t、金属管に生じさせる増肉率β(=増肉
により増加した肉厚÷増肉前の肉厚)に対して、 g≒0.5tβ と設定すればよい。一般に、増肉をダイスを用いない前
記フリー増肉法によって行った場合、増肉は管壁の内外
面にほぼ等しく生じるので、上記の間隙gを採用してお
くと、管壁の増肉変形によって内面側に膨出した部分が
前記間隙gをほぼ満たすこととなり、厚肉部の内面が熱
処理用ダイス外面にほぼ接触する状態即ち軽く接触する
か或いは両者間に微小な隙間が生じた状態となる。即
ち、熱処理用ダイスは増肉加工時において管壁内面の位
置を、フリー増肉が好ましく行われた(図4のような凹
みが生じない)場合の位置に制限する整形用ダイスとし
て作用し、増肉によって形成される厚肉部の内面を整っ
た形状に規制する。
In order to bring the heat treatment die into almost contact with the inner surface of the thick portion, the gap g between the heat treatment die and the metal pipe before being thickened is set before the thickness increase. With respect to the wall thickness t of the tube wall and the thickness increase ratio β (= thickness increased by the thickness increase / thickness before the thickness increase) to be generated in the metal pipe, g≈0.5tβ may be set. Generally, when the thickness increase is performed by the above-mentioned free thickness increase method without using a die, the thickness increase occurs almost at the inner and outer surfaces of the pipe wall. As a result, the portion that bulges toward the inner surface almost fills the gap g, and the inner surface of the thick portion is in almost contact with the outer surface of the heat treatment die, that is, in the state where it is lightly contacted or there is a minute gap between the two. Become. That is, the heat treatment die acts as a shaping die that limits the position of the inner surface of the pipe wall during the thickening process to the position where the free thickening is preferably performed (the depression as shown in FIG. 4 does not occur). The inner surface of the thick portion formed by increasing the thickness is regulated to a regular shape.

【0011】熱処理用ダイスを厚肉部内面に強く接触さ
せてその厚肉部を支持する状態とするには、熱処理用ダ
イスを増肉加工前の金属管に挿入した状態での両者の間
隙gを、 0<g<0.5tβ と設定すればよい。ここで、間隙gを0よりも大きくし
たのは、熱処理用ダイスを金属管内に挿入する動作を容
易とするためである。この範囲に設定すると、増肉変形
によって内面側に膨出する管壁部分が前記間隙gを満た
して熱処理用ダイス外面に押し付けられ、その後はその
熱処理用ダイスで内面位置を規制された状態で外面側に
増肉を生じることとなる。換言すれば、熱処理用ダイス
は増肉加工時において管壁内面の位置を、フリー増肉の
場合よりも管外面方向にシフトさせて規制する内面用成
形ダイスとして作用し、増肉によって形成される厚肉部
の内面を所定形状に成形する。このように熱処理用ダイ
スを増肉加工時の内面用成形ダイスとして作用させる
と、厚肉部内面を平滑にし且つ所望寸法に成形できる。
In order to bring the heat treatment die into strong contact with the inner surface of the thick portion to support the thick portion, a gap g between the heat treatment die and the thickened portion is inserted into the metal pipe before the thickening process. Should be set as 0 <g <0.5tβ. Here, the gap g is made larger than 0 in order to facilitate the operation of inserting the heat treatment die into the metal tube. When set in this range, the tube wall portion that bulges inward due to the increased wall thickness fills the gap g and is pressed against the outer surface of the heat treatment die, and thereafter the outer surface is regulated by the heat treatment die at the inner surface position. This will cause thickening on the side. In other words, the heat treatment die acts as an inner surface forming die that restricts the position of the inner surface of the pipe wall by shifting the position of the inner surface of the pipe wall toward the outer surface of the pipe as compared with the case of free thickening, and is formed by the thickening. The inner surface of the thick portion is formed into a predetermined shape. In this way, when the heat treatment die is made to act as a molding die for the inner surface at the time of thickening, the inner surface of the thick portion can be made smooth and can be molded to a desired size.

【0012】なお、熱処理用ダイスは、特にこれを増肉
加工時の内面用成形ダイスとして作用させた場合、形成
された厚肉部は熱処理用ダイス外面に強く押し付けられ
た状態となっており、熱処理後にその熱処理用ダイスを
引き抜く動作が困難となる場合がある。そこで、この引
き抜き動作を容易とするため、熱処理用ダイスを縮小可
能な構造とすることが好ましい。縮小可能な構造の例と
しては、ねじ機構を利用して、熱処理用ダイスの外形寸
法を縮小可能とするとか、熱処理用ダイスとして金属管
を用い、その内部に液圧を供給して少し膨張させた状態
で使用し、引き抜き時には液圧を解放することで縮小さ
せる構成等を挙げることができる。
When the heat treatment die is used as a molding die for the inner surface during thickening, the thick portion formed is in a state of being strongly pressed against the outer surface of the heat treatment die. After the heat treatment, it may be difficult to pull out the heat treatment die. Therefore, in order to facilitate the drawing operation, it is preferable that the heat treatment die has a structure capable of being reduced. As an example of a structure that can be reduced, a screw mechanism can be used to reduce the outer dimensions of the heat treatment die, or a metal tube is used as the heat treatment die, and hydraulic pressure is supplied to the inside to expand it slightly. It is possible to cite a configuration in which it is used in a closed state and is reduced by releasing the hydraulic pressure at the time of withdrawal.

【0013】増肉及び熱処理の対象とする金属管が角形
管の場合においては、その中に挿入する熱処理用ダイス
は、角形管の厚肉部内面を全周に渡って拘束しうる構成
のものに限らず、平坦な管壁のみを凹みを生じないよう
拘束する構成としても所期の目的を達成しうる。この構
成とすると、熱処理用ダイスの製造が容易となり、ま
た、角形管からの抜き取りも容易となる利点が得られ
る。
When the metal pipe to be thickened and heat treated is a rectangular pipe, the heat treatment die to be inserted therein has a structure capable of restraining the inner surface of the thick portion of the rectangular pipe over the entire circumference. Not limited to this, the intended purpose can be achieved even with a configuration in which only a flat tube wall is constrained so as not to cause a recess. With this structure, it is possible to obtain an advantage that the heat treatment die can be easily manufactured and that the heat treatment die can be easily extracted from the rectangular tube.

【0014】上記したように、熱処理用ダイスを増肉加
工時における内面用成形ダイスとして作用させる場合に
は、増肉加工の開始時には増肉率を金属管の長手方向位
置に応じて一定比率で増加させ、金属管内面が熱処理用
ダイスに接触した時点以降はその増肉率の増加比率を約
半分に低下させ、所定の増肉率に達した後は増肉率を一
定に保って増肉加工を行う方法を採用することが好まし
い。この方法を採用すると、増肉加工で形成される厚肉
部の増肉開始側端部に、非増肉部から所定厚さの厚肉部
に到る一定勾配の斜面を形成することができ、応力集中
の生じにくい増肉部を形成できる。
As described above, when the heat treatment die is used as a molding die for the inner surface at the time of thickening processing, at the start of the thickening processing, the thickening rate is set at a constant ratio according to the longitudinal position of the metal pipe. After the time when the inner surface of the metal pipe comes into contact with the heat treatment die, the increase rate of the thickness increase rate is reduced to about half, and after reaching the predetermined rate, the thickness increase rate is kept constant and the thickness increase rate is increased. It is preferable to adopt a method of performing processing. By adopting this method, it is possible to form a slope with a constant gradient from the non-thickened portion to the thick portion of a predetermined thickness at the thickening start side end portion of the thick portion formed by the thickening process. As a result, it is possible to form a thickened portion where stress concentration is less likely to occur.

【0015】また、増肉加工の終了時には増肉率を金属
管の長手方向位置に応じて一定比率で減少させ、金属管
内面が熱処理用ダイスに非接触となった時点以降はその
増肉率の減少比率を約倍として減少させる方法を採用す
ることが好ましい。この方法を採用すると、増肉加工で
形成される厚肉部の増肉終了側端部に、所定厚さの厚肉
部から非増肉部に到る一定勾配の斜面を形成することが
でき、応力集中の生じにくい増肉部を形成できる。
Further, at the end of the thickness increasing process, the rate of increase in thickness is reduced at a constant rate according to the longitudinal position of the metal tube, and after the time when the inner surface of the metal tube is not in contact with the heat treatment die, the rate of increase in thickness is increased. It is preferable to adopt a method in which the reduction ratio of is reduced to about double. If this method is adopted, it is possible to form a slope with a constant gradient from the thick portion having a predetermined thickness to the non-thickened portion at the end portion of the thick portion formed by the thickening processing on the thickening end side. As a result, it is possible to form a thickened portion where stress concentration is less likely to occur.

【0016】金属管に対する増肉加工を行う際、更に、
金属管に形成する前記加熱部の外側に外面用成形ダイス
を配置し、増肉によって外側に変形する管壁の外面位置
を前記外面用成形ダイスによって規制する構成とするこ
ともできる。この構成を採用すると、増肉した管壁の外
面を成形して平滑にすることができる。また、この外面
用成形ダイスで管壁の外面側に生じる増肉量の一部を抑
制し、その分内面側を増肉させることが可能となり、外
面側の増肉量を必要に応じ内面側よりも少なくすること
ができる。
When thickening the metal tube,
It is also possible to dispose an outer surface forming die on the outside of the heating portion formed in the metal tube, and to control the outer surface position of the tube wall that is deformed outward by increasing the thickness by the outer surface forming die. If this configuration is adopted, the outer surface of the wall of the increased wall can be molded and made smooth. In addition, it is possible to suppress a part of the thickness increase on the outer surface side of the pipe wall with this outer surface forming die and increase the inner surface side by that amount, and increase the outer surface side thickness increase as necessary. Can be less than.

【0017】本発明は、また、上記した方法の実施に好
適な装置も提供する。すなわち、本発明の金属管の増肉
加工熱処理装置は、増肉加工すべき金属管内に、増肉加
工によって形成される厚肉部の内側に位置するように挿
入され、前記厚肉部の長さ以上の長さを有する熱処理用
ダイスと、前記金属管に長手方向の圧縮力を作用させる
圧縮装置と、前記金属管の長手方向の小領域を加熱して
赤熱状態の加熱部を形成する加熱装置と、その加熱部の
一端を冷却する冷却装置と、前記加熱装置及び冷却装置
を、角形管に対して相対的に移動させる移動装置と、前
記加熱装置の後ろに該加熱装置と一緒に移動するように
設けられ、増肉加工によって形成された厚肉部の小領域
を、熱処理を行う温度に加熱して熱処理加熱部を形成す
る補助加熱装置とを有することを特徴とする。この構成
の装置では、加熱装置が金属管を局部的に加熱して増肉
を生じさせ且つその金属管に相対的に移動して厚肉部を
形成してゆく増肉加工動作と並行して、その厚肉部の小
領域を補助加熱装置が加熱して熱処理加熱部を形成し、
且つその補助加熱装置が金属管に対して相対的に移動し
て前記熱処理加熱部を厚肉部の長手方向に相対的に移動
させ、厚肉部の全域の熱処理を行うことができ、作業効
率が良い。また、単一の移動装置によって増肉用の加熱
装置と熱処理用の補助加熱装置とを金属管に相対的に移
動させることができ、装置構成を簡略化できる。
The present invention also provides an apparatus suitable for carrying out the method described above. That is, the thickening heat treatment apparatus for a metal pipe of the present invention is inserted into a metal pipe to be thickened so as to be located inside a thick portion formed by the thickening work, and the length of the thick portion is increased. A die for heat treatment having a length equal to or more than a length, a compression device for exerting a compressive force in the longitudinal direction on the metal tube, and heating for heating a small region in the longitudinal direction of the metal tube to form a heating part in a red heat state A device, a cooling device for cooling one end of a heating part thereof, a moving device for moving the heating device and the cooling device relative to a rectangular tube, and a moving device behind the heating device together with the heating device. And a supplementary heating device for heating the small region of the thick portion formed by the thickness increasing process to a temperature at which the heat treatment is performed to form the heat treatment heating portion. In the apparatus having this configuration, the heating device locally heats the metal pipe to cause the thickness increase, and moves relatively to the metal pipe to form the thick portion in parallel with the thickness increasing operation. , An auxiliary heating device heats a small area of the thick part to form a heat treatment heating part,
In addition, the auxiliary heating device moves relative to the metal pipe to move the heat treatment heating portion relatively in the longitudinal direction of the thick portion, and heat treatment of the entire thick portion can be performed, resulting in work efficiency. Is good. Further, the heating device for thickening and the auxiliary heating device for heat treatment can be moved relatively to the metal pipe by a single moving device, and the device configuration can be simplified.

【0018】[0018]

【発明の実施の形態】図1は本発明方法の実施に用いる
増肉加工熱処理装置の好適な例を示す概略断面図、図2
(a)、(b)はそれぞれ図1の矢印A−A断面図、矢
印B−B断面図、図3は図1における増肉加工部分の拡
大断面図である。1は増肉加工すべき金属管であり、こ
こでは角形鋼管が使用されている。以下、この金属管1
を角形管という。角形管1は図2から良く分かるよう
に、4つの平坦な管壁(以下側壁という)1aと、4つ
のコーナー部の円弧状に湾曲した管壁(以下コーナー壁
という)1bを有している。この実施例では、この角形
管1に対して、図1に長さLで示す領域に厚肉部1A
(一部を二点鎖線で示している)を形成する場合を示
す。なお、説明の便宜上、角形管1の長手方向の領域の
なかで、増肉加工をしないで元の肉厚のまま残す部分を
非増肉部1B、1Cとし、増肉加工を行うがまだ増肉さ
せてない部分を未増肉部1Dとする。
1 is a schematic sectional view showing a preferred example of a thickening heat treatment apparatus used for carrying out the method of the present invention, FIG.
(A), (b) is an arrow AA sectional view of FIG. 1, an arrow BB sectional view, respectively, and FIG. 3 is an enlarged sectional view of the thickened portion in FIG. Reference numeral 1 is a metal pipe to be thickened, and a rectangular steel pipe is used here. Hereafter, this metal tube 1
Is called a square tube. 2, the rectangular tube 1 has four flat tube walls (hereinafter referred to as side walls) 1a and four corner-shaped arc-shaped tube walls (hereinafter referred to as corner walls) 1b. . In this embodiment, with respect to the rectangular tube 1, a thick wall portion 1A is formed in a region indicated by a length L in FIG.
A case of forming (a part is shown by a chain double-dashed line) is shown. For the sake of convenience of explanation, in the region in the longitudinal direction of the rectangular tube 1, the portions which are not thickened and are left as the original thickness are the non-thickened portions 1B and 1C, and the thickening is still performed. The non-thickened portion is referred to as a non-thickened portion 1D.

【0019】2は角形管1の一端を定位置に固定、保持
する固定装置、3は角形管1の反対端を押圧して角形管
に圧縮力を作用させる油圧シリンダ等の圧縮装置、4
は、角形管1の長手方向の小領域を局部的に加熱して赤
熱状態の加熱部5とすることの可能な環状の加熱装置で
あり、ここでは高周波加熱コイルが使用されている。こ
の加熱装置4は、角形管1に沿って矢印C方向に移動す
る際に冷却水等の冷却媒体7を加熱部5の移動方向に関
して後端となる部分に吹き付ける冷却装置6(図3参
照)を備えている。8は加熱装置4及び冷却装置6を角
形管1に沿って所望の速度で移動させる移動装置であ
り、加熱装置4及び冷却装置6を保持して移動する移動
台8aと、その移動台8aを移動させる送りねじ8b
と、その送りねじ8bを回転駆動するモータ8c等を備
えている。なお、移動装置8としては、図示実施例に示
すモータと送りねじを用いたものに限らず、モータと送
り用チェーンを用いたもの、デジタルシリンダを用いた
もの等、適宜変更可能である。
Reference numeral 2 is a fixing device for fixing and holding one end of the rectangular tube 1 in a fixed position, 3 is a compression device such as a hydraulic cylinder for pressing the opposite end of the rectangular tube 1 to apply a compressive force to the rectangular tube, 4
Is an annular heating device capable of locally heating a small region in the longitudinal direction of the rectangular tube 1 to form a heating part 5 in a red hot state, and a high frequency heating coil is used here. The heating device 4 sprays a cooling medium 7 such as cooling water on a rear end portion in the moving direction of the heating part 5 when the heating device 4 moves in the direction of the arrow C along the rectangular tube 1 (see FIG. 3). Is equipped with. A moving device 8 moves the heating device 4 and the cooling device 6 along the rectangular tube 1 at a desired speed. The moving device 8a holds the heating device 4 and the cooling device 6 and moves, and the moving device 8a. Moving feed screw 8b
And a motor 8c for rotating the feed screw 8b. The moving device 8 is not limited to the one using the motor and the feed screw shown in the illustrated embodiment, but may be appropriately changed to one using a motor and a feed chain, one using a digital cylinder, or the like.

【0020】9は、加熱装置4の後ろに相互に干渉しな
いように適当な距離をおいて配置され且つ加熱装置4と
一緒に移動するように移動台8aに保持された熱処理用
の補助加熱装置であり、増肉加工により形成された厚肉
部1Aの小領域を環状に且つ所望の熱処理温度に加熱し
て熱処理加熱部26を形成するためのものである。この
補助加熱装置9としても、高周波加熱コイルが使用され
ている。補助加熱装置9には、必要に応じ熱処理加熱部
26の後端を水噴射等によって冷却する冷却装置が設け
られて良い。なお、補助加熱装置9の前には、角形管1
に噴射された冷却媒体7の影響をなくすよう水切り24
が配置されている。
Reference numeral 9 denotes an auxiliary heating device for heat treatment, which is arranged behind the heating device 4 at an appropriate distance so as not to interfere with each other and is held on a moving table 8a so as to move together with the heating device 4. This is for forming the heat treatment heating portion 26 by heating the small region of the thick portion 1A formed by the thickness increasing process annularly and to a desired heat treatment temperature. A high frequency heating coil is also used as the auxiliary heating device 9. The auxiliary heating device 9 may be provided with a cooling device that cools the rear end of the heat treatment heating unit 26 by water injection or the like, if necessary. In addition, in front of the auxiliary heating device 9, the rectangular tube 1
Drainer 24 to eliminate the influence of the cooling medium 7 sprayed on
Is arranged.

【0021】10は、角形管1の内側に配置された熱処
理用ダイスであり、厚肉部1Aの熱処理時に厚肉部内面
位置を規制してゆがみ発生を防止するためのものであ
る。本実施例では熱処理用ダイス10として図2に示す
ように、角形管1の内面と相似な外面を有する角形管が
使用されており、角形管1の側壁1aの内面に対向する
平坦な側壁ダイス面10aと角形管1のコーナー壁1b
に対向する円弧状のコーナーダイス面10bを有してい
る。更に、内部には、向かい合った壁面間隔を一定に保
つための補強材10cを配置している。この補強材10
cは必要に応じて設ければよく、また、その構造も任意
であり、例えば、単に剛性を有する鋼材を溶接等によっ
て固定したものでもよいし、ボルト、ナットを組み合わ
せたターンバックル等を用い、熱処理用ダイス10の壁
面間隔を調整可能としたものでもよい。補強材10cと
して、それを取り付けている壁面間隔を調整可能なもの
を用いると、外形寸法(互いに反対側に位置する側壁ダ
イス面10a、10a間距離)を変化させることがで
き、このため増肉加工及び熱処理を終了し、その熱処理
用ダイス10を角形管1から引き抜く時に、その熱処理
用ダイスの外形寸法を縮小させることで、引抜きを容易
とすることができる利点が得られる。なお、熱処理用ダ
イス10は、必要に応じ加熱する構成、或いは冷却する
構成としてもよい。
Reference numeral 10 denotes a heat treatment die arranged inside the rectangular tube 1 for preventing the occurrence of distortion by regulating the inner surface position of the thick portion 1A during the heat treatment of the thick portion 1A. In this embodiment, as the heat treatment die 10, as shown in FIG. 2, a rectangular tube having an outer surface similar to the inner surface of the rectangular tube 1 is used, and a flat sidewall die facing the inner surface of the sidewall 1a of the rectangular tube 1. Surface 10a and corner wall 1b of rectangular tube 1
It has an arc-shaped corner die surface 10b opposed to. Further, a reinforcing material 10c is arranged inside for maintaining a constant distance between the facing wall surfaces. This reinforcement 10
c may be provided as needed, and its structure is also arbitrary. For example, a rigid steel material may be fixed by welding or the like, or a turnbuckle in which bolts and nuts are combined is used, The heat treatment die 10 may have an adjustable wall surface interval. When the reinforcing material 10c having a wall surface interval to which it is attached is adjustable, the outer dimension (distance between the side wall die surfaces 10a and 10a located on opposite sides) can be changed, and thus the thickness increase When the heat treatment die 10 is drawn out from the rectangular tube 1 after the processing and heat treatment are completed, it is possible to obtain an advantage that the drawing can be facilitated by reducing the outer dimension of the heat treatment die. The heat treatment die 10 may be heated or cooled as necessary.

【0022】この熱処理用ダイス10は角形管1に形成
する厚肉部1Aの長さLよりも長い長さを有しており、
且つその厚肉部1Aを形成する領域に位置するように、
固定装置2に固定して設けられる。
This heat treatment die 10 has a length longer than the length L of the thick wall portion 1A formed in the rectangular tube 1,
And, so that it is located in the region where the thick portion 1A is formed,
It is fixedly provided on the fixing device 2.

【0023】熱処理用ダイス10の外形寸法は、増肉加
工によって形成された厚肉部1Aを熱処理する時に厚肉
部内面位置を規制してゆがみ発生を防止しうるように定
められるものであり、具体的には、熱処理用ダイス10
の外周面が厚肉部1Aの内面に強く接触してその厚肉部
1Aを支持するような寸法、或いは、ほぼ接触するよう
な寸法に定められる。更に、具体的には、熱処理用ダイ
ス10を増肉前の角形管1内に容易に挿入しうるよう、
熱処理用ダイス10の側壁ダイス面10aと増肉前の角
形管1の側壁1aの内面との間に、0より大きい間隙g
が存在し、且つその間隙gが、角形管1を増肉加工した
際に増肉によって完全に或いはほぼ満たされるような寸
法に定められる。一般に、角形管1を圧縮して増肉させ
る際、内外面を拘束しない場合には通常、増肉は内側、
外側にほぼ等しく生じる。このため増肉率βを、「増肉
により増加した肉厚Δt(=増肉後の肉厚T−増肉前の
肉厚t)÷増肉前の肉厚t」と定義すると、増肉率βの
増肉を行った時、角形管1の側壁1aの内面は増肉によ
り、0.5×t×βだけ、内側に膨出することとなる。
従って、前記した間隙gを0.5tβにほぼ等しくする
か或いはそれより小さく設定しておけば、増肉加工時に
側壁1aの内側への膨出によって前記間隙gがほぼ満た
されるか或いは完全に満たされることとなり、増肉によ
り形成された厚肉部1Aの内面が、側壁ダイス面10a
にほぼ接触する状態(軽く接触するか接触しないとして
もその間隙が微小な状態)或いは強く接触する状態とな
り、厚肉部1Aの熱処理時に厚肉部1Aのゆがみ発生を
防止できる。
The outer dimensions of the heat treatment die 10 are determined so as to prevent the occurrence of distortion by restricting the inner surface position of the thick portion when heat treating the thick portion 1A formed by the thickening process. Specifically, the heat treatment die 10
The outer peripheral surface of is thickly contacted with the inner surface of the thick portion 1A so as to support the thick portion 1A, or is so dimensioned as to be substantially in contact therewith. Furthermore, specifically, in order to easily insert the heat treatment die 10 into the rectangular tube 1 before thickening,
A gap g larger than 0 between the side wall die surface 10a of the heat treatment die 10 and the inner surface of the side wall 1a of the rectangular tube 1 before thickening.
Is present, and the gap g is determined such that when the rectangular tube 1 is thickened, it is completely or almost completely filled with the thickening. In general, when the rectangular tube 1 is compressed to increase the thickness, if the inner and outer surfaces are not constrained, the thickness increase is usually the inner side,
It occurs almost equally on the outside. Therefore, if the thickness increase ratio β is defined as “thickness Δt increased by thickness increase (= thickness T after thickness increase−thickness t before thickness increase) / thickness t before thickness increase”, the thickness increase When the thickness is increased by the rate β, the inner surface of the side wall 1a of the rectangular tube 1 is bulged inward by 0.5 × t × β due to the increased thickness.
Therefore, if the gap g is set to be substantially equal to 0.5tβ or smaller than 0.5tβ, the gap g is almost or completely filled by the bulging of the side wall 1a during the thickening process. Therefore, the inner surface of the thick portion 1A formed by increasing the thickness is the side wall die surface 10a.
The state in which the thick portion 1A is almost in contact with the thick portion 1A (a slight gap even if it is not lightly contacted) or a state in which the thick portion 1A is strongly contacted can prevent the thick portion 1A from being distorted during the heat treatment.

【0024】本実施例では、この間隙gを0.5tβに
ほぼ等しく設定している。コーナー壁1bとコーナーダ
イス面10bとの間隙も、上記した間隙gと同様に定め
られる。なお、上記した間隙gは理論的なものであり、
実際の設計に当たっては熱処理用ダイス10の熱膨張を
考慮して、適宜補正することが好ましい。
In this embodiment, this gap g is set to be approximately equal to 0.5tβ. The gap between the corner wall 1b and the corner die surface 10b is also defined in the same manner as the gap g described above. The above-mentioned gap g is theoretical,
In the actual design, it is preferable to make an appropriate correction in consideration of the thermal expansion of the heat treatment die 10.

【0025】次に、上記構成の増肉加工装置の増肉加工
熱処理時の動作を説明する。図1において、増肉加工す
べき角形管1の一端を固定装置2に固定、保持させ、そ
の反対端を油圧シリンダ等の圧縮装置3で押圧して角形
管1に圧縮力を作用させた状態で、加熱装置4によって
角形管1の長手方向の小領域を加熱して、塑性変形容易
な赤熱状態の加熱部5とし、その加熱部5に圧縮力によ
る増肉を生じさせながら、その加熱装置4を角形管1に
沿って矢印C方向に移動させ、同時に冷却手段6から冷
却媒体7を加熱部5の後端部分に吹き付けて増肉直後の
部分を冷却、固化する。これにより角形管1が長手方向
に連続的に増肉させられ、厚肉部1Aが形成されてゆ
く。
Next, the operation of the above-structured thickness increasing apparatus during heat treatment for increasing thickness will be described. In FIG. 1, a state in which one end of the rectangular pipe 1 to be thickened is fixed and held by a fixing device 2 and the opposite end is pressed by a compression device 3 such as a hydraulic cylinder to apply a compressive force to the rectangular pipe 1. Then, a small area in the longitudinal direction of the rectangular tube 1 is heated by the heating device 4 to form a heating part 5 in a red hot state that is easily plastically deformed. 4 is moved in the direction of arrow C along the rectangular tube 1, and at the same time, the cooling medium 7 is sprayed from the cooling means 6 to the rear end portion of the heating portion 5 to cool and solidify the portion immediately after the thickness increase. As a result, the rectangular tube 1 is continuously thickened in the longitudinal direction, and the thick portion 1A is formed.

【0026】この増肉加工動作中、移動台8aの移動に
よって補助加熱装置9も移動し、その補助加熱装置9が
厚肉部1Aの端部に達すると、補助加熱装置9が加熱を
開始し、厚肉部1Aの小領域を所望の熱処理温度に加熱
して熱処理加熱部26を形成しながら、矢印C方向に移
動し、その熱処理加熱部26の後端を強制冷却するか放
冷する。これにより、厚肉部1Aが連続的に熱処理され
る。かくして、加熱部5に於ける増肉加工と熱処理加熱
部26における熱処理が並行して行われ、所望長さLの
厚肉部1Aが形成され、その厚肉部1の終端まで熱処理
加熱部26が移動した時点で、動作が終了する。これに
より、所定長さLの厚肉部1Aが形成されると共にその
全体が熱処理され、機械的特性の改善が図られる。
During this thickening operation, the auxiliary heating device 9 is also moved by the movement of the moving table 8a, and when the auxiliary heating device 9 reaches the end of the thick portion 1A, the auxiliary heating device 9 starts heating. While the small area of the thick portion 1A is heated to a desired heat treatment temperature to form the heat treatment heating portion 26, it moves in the direction of arrow C and the rear end of the heat treatment heating portion 26 is forcibly cooled or left to cool. Thereby, the thick portion 1A is continuously heat-treated. Thus, the thickening process in the heating unit 5 and the heat treatment in the heat treatment heating unit 26 are performed in parallel to form the thick portion 1A having the desired length L, and the heat treatment heating unit 26 reaches the end of the thick portion 1. The operation ends when is moved. As a result, the thick portion 1A having the predetermined length L is formed and the whole is heat-treated, so that the mechanical characteristics are improved.

【0027】ところで、角形管1の内外面をなんら拘束
しない状態で増肉加工した場合には、圧縮変形及び冷却
による収縮変形等により、得られた厚肉部1Aの断面形
状は図4(b)に示すようになる傾向があり、平坦であ
るべき側壁1Aaが内側に凹み、その位置に凹み12
(凹み量e)を生じ、平坦度が低下するという現象があ
り、これを防止するには、加熱温度、増肉加工速度、冷
却速度等を凹みの生じにくい狭い条件範囲に設定する必
要があった。また、側壁1Aaへの凹み発生現象は厚肉
部1Aを熱処理する時にも生じており、特に熱処理時に
凹み量eが大きくなる傾向があった。これに対し、本実
施例においては、増肉加工の際、内側に熱処理用ダイス
10が存在しているため、加熱部5が圧縮力により増肉
し、その際凹み12が生じようとしても、増肉した部分
の内面が熱処理用ダイス10の平坦なダイス面10aに
接触して規制され、その状態で冷却されて固化する。か
くして、形成された厚肉部1Aには凹み12はほとんど
生じない。次いで、その厚肉部1Aが熱処理のために加
熱され、その際にも平坦な側壁1Aaに凹み12が生じ
ようとするが、その内面が熱処理用ダイス10の平坦な
ダイス面10aによって規制され、平坦に保たれたまま
熱処理される。かくして、図4(a)に示すように、側
壁1Aaに対する凹みの発生が抑制され、角形管1の管
壁に対して内外面にほぼ等しい増肉を生じながら、側壁
への凹み発生を防止した状態で増肉加工及び熱処理が行
われ、平坦度の良い側壁1Aaを備えた厚肉部1Aが形
成される。
By the way, when the thickening is performed without restraining the inner and outer surfaces of the rectangular tube 1, the cross-sectional shape of the thick portion 1A obtained by compressive deformation and contractive deformation by cooling is shown in FIG. ), The side wall 1Aa, which should be flat, is recessed inward and recessed at that position 12
(Depression amount e) occurs and flatness decreases, and in order to prevent this, it is necessary to set the heating temperature, the thickening processing speed, the cooling speed, etc. within a narrow condition range in which depression is less likely to occur. It was Further, the phenomenon of dents on the side wall 1Aa also occurs when the thick portion 1A is heat-treated, and the dent amount e tends to increase particularly during the heat treatment. On the other hand, in the present embodiment, since the heat treatment die 10 is present inside during the thickness increasing process, even if the heating portion 5 increases the thickness due to the compressive force and the depression 12 tends to occur at that time, The inner surface of the thickened portion contacts the flat die surface 10a of the heat treatment die 10 and is regulated, and in that state, it is cooled and solidified. Thus, the recess 12 hardly occurs in the formed thick portion 1A. Next, the thick portion 1A is heated for heat treatment, and the recess 12 is likely to occur in the flat side wall 1Aa at that time as well, but the inner surface thereof is restricted by the flat die surface 10a of the heat treatment die 10, It is heat-treated while being kept flat. Thus, as shown in FIG. 4 (a), the formation of depressions on the side wall 1Aa is suppressed, and the formation of depressions on the side wall is prevented while substantially increasing the inner and outer surfaces of the pipe wall of the rectangular tube 1 substantially. In the state, the thickening process and the heat treatment are performed to form the thick portion 1A including the side wall 1Aa having good flatness.

【0028】上記した実施例では、更に次のような利点
も得られる。すなわち、側壁1Aaに対する凹みの発生
を熱処理用ダイス10で抑制可能であるため、凹みの発
生を抑制するために増肉加工速度を低く抑える必要がな
くなり、このため増肉加工速度を高めて生産性を上げる
ことが可能である。また、増肉加工を生じている部分の
内面を熱処理用ダイス10が支持するため、厚肉加工時
に生じ勝ちなじゃばら状の変形(図13参照)が生じに
くく、このため増肉加工条件(例えば、加熱部の温度、
圧縮力、冷却速度、増肉加工速度等)に多少の変動が生
じても、良好な増肉加工が可能であり、操業性が向上す
る。更に、加熱部温度を低下させた状態での増肉加工も
可能となり、増肉加工時の加熱、冷却による硬化を抑制
し、増肉加工部の機械的物性の低下を抑制できる。ま
た、厚肉部1A全体の内面を熱処理用ダイス10で規制
することにより、厚肉部1Aの内面を平滑とすることが
できると共に、厚肉部1Aの真直度も高めることがで
き、厚肉部1Aの品質を向上できる。
The above-described embodiment also has the following advantages. That is, since it is possible to suppress the occurrence of depressions on the side wall 1Aa by the heat treatment die 10, it is not necessary to keep the thickness increase processing speed low in order to suppress the occurrence of depressions. Therefore, the thickness increase processing speed is increased to improve productivity. It is possible to raise. Further, since the heat treatment die 10 supports the inner surface of the portion where the thickness increasing process is performed, the bellows-like deformation (see FIG. 13) that is apt to occur during the thickness increasing process is unlikely to occur, and thus the thickness increasing process condition (for example, , The temperature of the heating part,
Even if the compression force, the cooling speed, the thickening processing speed, etc.) fluctuates to some extent, good thickening processing is possible and the operability is improved. Further, it is possible to perform a thickness increasing process in a state where the temperature of the heating part is lowered, and it is possible to suppress hardening due to heating and cooling during the thickness increasing process, and to suppress deterioration of mechanical properties of the thickness increasing part. Further, by regulating the inner surface of the entire thick portion 1A with the heat treatment die 10, the inner surface of the thick portion 1A can be made smooth, and the straightness of the thick portion 1A can be increased. The quality of the part 1A can be improved.

【0029】なお、この実施例では、角形管1のコーナ
ー壁1b内面にコーナーダイス面10bを位置させ、増
肉したコーナー壁内面も規制している。しかしながら、
コーナー壁1bには増肉時或いは熱処理時において凹み
等の異常は生じにくいので、このコーナー壁1bの内面
は必ずしも規制する必要はなく、従って、図5(a)に
示すように、コーナー壁1bの内面とそれに対向するコ
ーナーダイス面10bとの間隙を大きくして、増肉して
も両者が非接触のままとするとか、図5(b)に示すよ
うに、内面用成形ダイス10を、隣接した平坦なダイス
面10a、10aのコーナー部分が切り欠かれた、コー
ナーダイス面の無い形状とする等の変更を行うことも可
能である。
In this embodiment, the corner die surface 10b is located on the inner surface of the corner wall 1b of the rectangular tube 1 to regulate the inner wall of the thickened corner wall. However,
Since an abnormality such as a dent is unlikely to occur in the corner wall 1b during thickening or heat treatment, the inner surface of the corner wall 1b does not necessarily have to be regulated. Therefore, as shown in FIG. The inner surface of the inner die and the corner die surface 10b facing the inner surface of the inner die are enlarged so that the two remain in non-contact with each other even if the thickness is increased, or as shown in FIG. It is also possible to change the corner portions of the adjacent flat die surfaces 10a, 10a such that the corner portions are notched or the corner die surface is not formed.

【0030】上記実施例では、角形管1の内外面にほぼ
等しい増肉を生じさせるように増肉を行っているが、内
外面における増肉量を異ならせることも可能である。図
6は外面側の増肉量を多くした場合の実施例を示すもの
であり、この実施例では、角形管1の内側にセットする
熱処理用ダイス10の寸法を、図3に示すものよりも大
きくし、角形管1の増肉前の管壁内面との間隙gを小さ
くしている。すなわち、 g<0.5tβ としている。ただし、金属管1に対して熱処理用ダイス
10の挿入を容易とするため、間隙gは0より大として
いる。その他の構成は、図1〜図3に示す実施例と同様
である。
In the above embodiment, the wall thickness is increased so that the inner and outer surfaces of the rectangular tube 1 have substantially the same thickness. However, the inner and outer surfaces may have different amounts of wall thickness increase. FIG. 6 shows an embodiment in which the amount of thickness increase on the outer surface side is increased. In this embodiment, the size of the heat treatment die 10 set inside the rectangular tube 1 is larger than that shown in FIG. The gap g between the square tube 1 and the inner surface of the tube wall before thickening is made small. That is, g <0.5tβ. However, in order to facilitate insertion of the heat treatment die 10 into the metal tube 1, the gap g is set to be larger than zero. Other configurations are similar to those of the embodiment shown in FIGS.

【0031】図6の実施例では、加熱部5が増肉された
際、内側への変形量が間隙gよりも大きくなろうとする
ため、その内面が熱処理用ダイス10の外面に強く押し
付けられ、その熱処理用ダイス10の形状に成形され、
従って、内側への変形量が制限され、その分、外面側の
増肉量が増加した状態で増肉が行われる。この時、増肉
された部分の内面を熱処理用ダイス10の平坦な側壁ダ
イス面10aが平坦に拘束しているので、図4(b)に
示したような凹み12が生じることはない。更に、増肉
加工によって形成された厚肉部1Aは熱処理用ダイス1
0に強く押し付けられた状態のままで、補助加熱装置9
によって加熱され、熱処理される。このため、熱処理時
においても、厚肉部1Aの平坦な側壁1Aaは平坦な側
壁ダイス面10aで平坦に拘束された状態を保持してお
り、図4(b)に示したような凹み12が生じることは
ない。
In the embodiment of FIG. 6, when the thickness of the heating portion 5 is increased, the amount of inward deformation tends to be larger than the gap g, so that the inner surface thereof is strongly pressed against the outer surface of the heat treatment die 10, Molded into the shape of the heat treatment die 10,
Therefore, the amount of deformation inward is limited, and the amount of thickness increase on the outer surface side is correspondingly increased. At this time, since the flat side wall die surface 10a of the heat treatment die 10 is flatly restraining the inner surface of the thickened portion, the recess 12 as shown in FIG. 4B does not occur. Further, the thick portion 1A formed by the thickening process is the heat treatment die 1
Auxiliary heating device 9 while being strongly pressed to 0
Is heated and heat-treated. Therefore, even during the heat treatment, the flat side wall 1Aa of the thick portion 1A is kept flatly restrained by the flat side wall die surface 10a, and the recess 12 as shown in FIG. It never happens.

【0032】上記した増肉加工を行う際の増肉率βは、
加熱部5の移動速度及びその加熱部5に向かって押し込
まれる角形管1の未増肉部分1Dの速度によって決ま
る。いま、図1において、加熱部5の後ろに位置する角
形管1の厚肉部1A或いはその後ろの非増肉部分1Bに
対する加熱部5の移動速度をW、加熱部5の前の未増肉
部分1Dの移動速度をVとすると、増肉率βは、 β=V/W で表される。ここで、この実施例では、厚肉部1A或い
はその後ろの非増肉部分1Bは固定装置2によって移動
しないように構成されているため、上記した加熱部5の
移動速度Wは、加熱装置4の移動速度に等しく、また、
未増肉部分1Dの移動速度Vは圧縮装置3が角形管1の
端部を押し込む速度に等しくなっている。従って、加熱
装置4の移動速度Wと圧縮装置3による押し込み速度V
の比を一定に保つことにより、例えば、加熱装置4の移
動速度Wを一定に保ち且つ圧縮装置3による押し込み速
度Vを一定に保つことにより、一定増肉率での増肉加工
が行われる。ここで、圧縮装置3による押し込み速度を
一定に保つには、圧縮装置3による圧縮力を一定に保ち
且つ加熱部5の温度を一定に保つ(これにより加熱部5
の平均変形抵抗を一定に保つ)方法、圧縮装置3として
押し込み速度を制御可能なもの(例えば、デジタルシリ
ンダ、デジタルサーボ機構等を備えたもの)を用い、圧
縮装置3の制御により一定の押し込み速度に保持する方
法等を用いることができる。
The thickness increase rate β when performing the above-mentioned thickness increase processing is
It is determined by the moving speed of the heating part 5 and the speed of the non-thickened portion 1D of the rectangular tube 1 pushed toward the heating part 5. Now, in FIG. 1, the moving speed of the heating part 5 with respect to the thick part 1A of the rectangular tube 1 located behind the heating part 5 or the non-thickened part 1B behind it is W, and the unthickened part in front of the heating part 5 is W. When the moving speed of the portion 1D is V, the thickness increase rate β is represented by β = V / W 2. Here, in this embodiment, the thick portion 1A or the non-thickened portion 1B behind the thick portion 1A is configured so as not to move by the fixing device 2. Therefore, the moving speed W of the heating unit 5 is set to the heating device 4 as described above. Equal to the moving speed of
The moving speed V of the non-thickened portion 1D is equal to the speed at which the compression device 3 pushes the end of the rectangular tube 1. Therefore, the moving speed W of the heating device 4 and the pushing speed V of the compression device 3
By maintaining a constant ratio, for example, the moving speed W of the heating device 4 is kept constant and the pushing speed V by the compression device 3 is kept constant, thickening is performed at a constant thickening rate. Here, in order to keep the pushing speed by the compression device 3 constant, the compression force by the compression device 3 is kept constant and the temperature of the heating part 5 is kept constant (therefore, the heating part 5).
Method for maintaining constant average deformation resistance), a compression device 3 having a controllable pressing speed (for example, a device having a digital cylinder, a digital servo mechanism, etc.) is used, and a constant pressing speed is controlled by the control of the compression device 3. And the like can be used.

【0033】ところで、一定肉厚の角形管1に対して増
肉加工を開始する際、単に最初から所定の増肉率βとな
るように増肉加工を開始すると、図7(a)に示すよう
に、厚肉部1Aの開始点において非増肉部分1Bとの間
に段部14が形成されてしまう。このような段部14は
応力集中を生じさせるので好ましくなく、従って、図7
(b)に示すような傾斜面15を形成することが好まし
い。増肉加工によって形成する厚肉部の肉厚をTとする
と、その肉厚Tと増肉率βとの間には、 T=(1+β)t の関係がある。従って、増肉率βを変化させることで、
肉厚Tを変化させることが可能であり、図7(b)にお
いて、増肉開始点Dから角形管1の長手方向位置に応じ
て増肉率βを一定比率で増加するように変化させること
で、厚肉部1Aの開始位置に傾斜面15を形成すること
ができ、その増肉率βが所定の値に達した後(点Eに達
した後)は増肉率βを一定に保って増肉加工を行うこと
により、増肉開始部分に傾斜面15を有する一定厚みの
厚肉部1Aを形成することが可能となる。
By the way, when the thickening process is started for the rectangular tube 1 having a constant thickness, the thickening process is simply started from the beginning so as to obtain a predetermined thickening rate β, as shown in FIG. 7 (a). Thus, the step portion 14 is formed between the thick portion 1A and the non-thickened portion 1B at the starting point. Such a step 14 is not preferable because it causes stress concentration, and therefore, FIG.
It is preferable to form the inclined surface 15 as shown in (b). When the thickness of the thick portion formed by the thickness increasing process is T, there is a relationship of T = (1 + β) t between the thickness T and the thickness increasing ratio β. Therefore, by changing the thickness increase ratio β,
It is possible to change the wall thickness T, and in FIG. 7 (b), change the wall thickness increase ratio β from the wall thickness increase start point D so as to increase at a constant ratio according to the position in the longitudinal direction of the rectangular tube 1. Thus, it is possible to form the inclined surface 15 at the start position of the thick portion 1A, and keep the thickness increase rate β constant after the thickness increase rate β reaches a predetermined value (after reaching the point E). By performing the thickening process by using the thickening process, it is possible to form the thick portion 1A having a constant thickness and having the inclined surface 15 at the thickening starting portion.

【0034】上記したように、増肉率βはV/Wに等し
いので、加熱装置4を角形管1に沿って移動させ加熱部
5を移動させて増肉が生じる位置を角形管1の長手方向
に移動させる際、その位置に応じてV/W(=β)が一
定比率で増加するように、加熱装置4の移動速度Wと圧
縮装置3による押し込み速度Vの一方若しくは双方を制
御する。これにより、増肉開始部分に傾斜面15を形成
することができ、また、その時に増加する比率を適当に
設定することにより、傾斜面15の傾斜を適当に設定で
きる。厚肉部1Aの終了部においても同様に、増肉が生
じる位置が角形管1の長手方向に移動するにつれて、そ
の位置に応じて、V/W(=β)が一定比率で減少する
ように、加熱装置4の移動速度Wと圧縮装置3による押
し込み速度Vの一方若しくは双方を制御する。これによ
り、厚みが徐々に小さくなるような傾斜面を形成でき
る。
As described above, since the thickness increase rate β is equal to V / W, the heating device 4 is moved along the rectangular tube 1 and the heating part 5 is moved so that the position where the thickness increase occurs is the longitudinal direction of the rectangular tube 1. When moving in the direction, one or both of the moving speed W of the heating device 4 and the pushing speed V of the compression device 3 are controlled so that V / W (= β) increases at a constant ratio according to the position. Thereby, the inclined surface 15 can be formed at the thickening start portion, and the inclination of the inclined surface 15 can be appropriately set by appropriately setting the increasing ratio at that time. Similarly, at the end of the thick portion 1A, V / W (= β) is reduced at a constant rate depending on the position where the increase in thickness moves in the longitudinal direction of the rectangular tube 1. One or both of the moving speed W of the heating device 4 and the pushing speed V of the compression device 3 are controlled. This makes it possible to form an inclined surface whose thickness is gradually reduced.

【0035】増肉加工で形成する厚肉部1Aの両端に上
記した傾斜面15を形成することは図1〜図3に示す実
施例の場合でも、図6に示す実施例の場合でも適用可能
である。ところが、図6に示す実施例のように、熱処理
用ダイス10で増肉部分を外面側に押し出す場合に適用
すると、若干問題が生じる。すなわち、図8(a)に示
すように、増肉開始部に一定勾配の傾斜面15を形成す
るように増肉率βを増加させて行く場合、図8(b)に
示すように、増肉率を増加させながら増肉位置が角形管
1の長手方向に移動し、内面側に増肉した部分が熱処理
用ダイス10に接触する位置Pを通り過ぎた後、内面側
に増肉しようとする部分(ハッチングaで示す部分)が
熱処理用ダイス10で制限されるため、その分外面側に
増肉することとなり、外面側にハッチングbで示す部分
が付加されたようになる。このため、傾斜面15が位置
Pのところで折れ曲がり、勾配の急な傾斜面15Aとな
る。このような折れ曲がりは応力集中の原因となるの
で、好ましくない。
The formation of the above-mentioned inclined surfaces 15 at both ends of the thick portion 1A formed by the thickening process can be applied to both the embodiment shown in FIGS. 1 to 3 and the embodiment shown in FIG. Is. However, as in the embodiment shown in FIG. 6, when it is applied to the case where the thickened portion is extruded to the outer surface side by the heat treatment die 10, a slight problem occurs. That is, as shown in FIG. 8A, when increasing the thickness increase rate β so as to form the inclined surface 15 with a constant slope at the thickness increase start portion, as shown in FIG. The wall thickness increasing position moves in the longitudinal direction of the rectangular tube 1 while increasing the wall thickness ratio, and after the portion having the wall thickness increasing on the inner surface side has passed the position P where it contacts the heat treatment die 10, it is attempted to increase the wall thickness on the inner surface side. Since the portion (portion indicated by hatching a) is limited by the heat treatment die 10, the thickness is increased on the outer surface side by that amount, and the portion indicated by hatching b is added to the outer surface side. Therefore, the inclined surface 15 bends at the position P, and the inclined surface 15A has a steep slope. Such bending is not preferable because it causes stress concentration.

【0036】本発明の一実施例ではこのような傾斜面の
折れ曲がりを防止することが可能である。すなわち、一
実施例では、図9(a)、(b)に示すように、増肉開
始点Dを過ぎるとまず増肉率β(=W/V)を、角形管
1の長手方向位置に応じて一定比率で増加させ、一定勾
配の傾斜面15を形成してゆき、内面側に増肉した部分
が熱処理用ダイス10に接触する位置Pを通り過ぎた後
は、その増加率の増加比率を約半分に低下させる。これ
により、図9(a)に示すように、熱処理用ダイス10
が無いものと仮定した場合には、位置Pの次に、先に形
成した傾斜面15の勾配の約半分の勾配を有する傾斜面
15Bが形成されることとなり、実際には、図9(b)
に示すように熱処理用ダイス10があるため内面側に増
肉しようとする部分(ハッチングaで示す部分)がその
熱処理用ダイス10で制限されてその分外面側に増肉す
ることとなり、外面側にハッチングbで示す部分が付加
され、傾斜面15Cが形成される。この傾斜面15Cの
勾配は傾斜面15にほぼ等しい。かくして、外面側に折
れ曲がりの殆どない傾斜面15、15Cが形成されるこ
ととなり、図9(c)に示すように応力集中を生じやす
い部分の無い厚肉部1Aを形成することができる。
In one embodiment of the present invention, it is possible to prevent such bending of the inclined surface. That is, in one embodiment, as shown in FIGS. 9A and 9B, when the thickening start point D is passed, the thickening ratio β (= W / V) is first set to the longitudinal position of the rectangular tube 1. Accordingly, the inclined surface 15 having a constant slope is formed at a constant rate, and after the portion P having the increased thickness on the inner surface side passes the position P at which the heat treatment die 10 is contacted, the increasing rate of the increase rate is increased. Reduce to about half. As a result, as shown in FIG. 9A, the heat treatment die 10 is formed.
If it is assumed that there is no gradient, a sloped surface 15B having a slope that is about half the slope of the sloped surface 15 that was formed earlier is formed next to the position P. )
Since the heat treatment die 10 is provided as shown in FIG. 3, the portion (portion indicated by hatching a) where the thickness is to be increased on the inner surface side is limited by the heat treatment die 10 and the thickness is increased to the outer surface side by that amount. Is added with a portion indicated by hatching b to form an inclined surface 15C. The slope of the inclined surface 15C is substantially equal to that of the inclined surface 15. Thus, the inclined surfaces 15 and 15C having almost no bending are formed on the outer surface side, and as shown in FIG. 9C, the thick portion 1A having no portion where stress concentration is likely to occur can be formed.

【0037】厚肉部1Aの終了部においても同様に、た
だし、増肉開始部とは逆に増肉率を変化させることによ
り、外面側に折れ曲がりの殆どない傾斜面を形成可能で
ある。すなわち、図10に示すように、増肉終了の開始
点Fを越えた時点から、増肉率β(=W/V)を、角形
管1の長手方向位置に応じて一定比率で減少させること
により、一定勾配の傾斜面16を形成してゆき(この
時、熱処理用ダイス10が無いと想定した場合には二点
鎖線で示す傾斜面16Aが形成される)、内面側に増肉
した部分が熱処理用ダイス10から離れる位置Qを通り
過ぎた後は、その増加率の減少比率を約倍に増加させ
る。これにより、位置Qの後ろには、内外面に傾斜面1
6Bが形成されることとなり、且つ外面側の傾斜面16
Bは、先に形成した傾斜面16と同じ勾配となる。かく
して、厚肉部1Aの終了部においても外面側に折れ曲が
りの殆どない傾斜面を形成できる。
Similarly at the end portion of the thick portion 1A, however, an inclined surface with almost no bending can be formed on the outer surface side by changing the thickness increasing rate in the opposite direction to the thickening starting portion. That is, as shown in FIG. 10, from the time when the starting point F of the end of the wall thickness increase is exceeded, the wall thickness increase rate β (= W / V) is reduced at a constant rate according to the longitudinal position of the rectangular tube 1. Thereby forming an inclined surface 16 having a constant gradient (at this time, if it is assumed that the heat treatment die 10 is not present, an inclined surface 16A indicated by a chain double-dashed line is formed), and the thickened portion on the inner surface side After passing the position Q away from the heat treatment die 10, the decrease rate of the increase rate is increased to about double. As a result, after the position Q, the inclined surface 1 is formed on the inner and outer surfaces.
6B is formed, and the inclined surface 16 on the outer surface side is formed.
B has the same slope as the inclined surface 16 formed previously. Thus, an inclined surface with almost no bending can be formed on the outer surface side even at the end portion of the thick portion 1A.

【0038】図11、図12は本発明の更に他の実施例
を示すものである。この実施例では、加熱装置4の後ろ
側に加熱装置4と一緒に移動するように外面用成形ダイ
ス20が配置されている。この外面用成形ダイス20
は、増肉よって外側に変形する管壁の外面位置を規制す
るダイス面20aを有すると共に、内部を冷却媒体で冷
却する構成となっており、そのダイス面20aに接触し
た管壁を冷却可能である。従って、この実施例では外面
用成形ダイス20が、角形管1の加熱部5の後端を冷却
する冷却手段を構成する。なお、この外面用成形ダイス
20の後ろに冷却媒体を角形管に噴射して冷却する冷却
手段を配置してもよい。
11 and 12 show still another embodiment of the present invention. In this embodiment, a molding die 20 for the outer surface is arranged behind the heating device 4 so as to move together with the heating device 4. This external forming die 20
Has a die surface 20a that regulates the outer surface position of the pipe wall that is deformed outward due to the increase in thickness, and is configured to cool the inside with a cooling medium. It is possible to cool the pipe wall that is in contact with the die surface 20a. is there. Therefore, in this embodiment, the outer surface forming die 20 constitutes cooling means for cooling the rear end of the heating portion 5 of the rectangular tube 1. A cooling means for injecting a cooling medium into the rectangular tube to cool it may be disposed behind the outer surface molding die 20.

【0039】熱処理用ダイス10と外面用成形ダイス2
0との間隔は、増肉加工によって形成する厚肉部1Aの
肉厚に等しく設定されている。外面用成形ダイス20と
角形管1の外面との間隙g′は、通常、管壁が増肉によ
り外面側に増肉する量よりも小さく、すなわち、 g′<0.5tβ に設定されている。従って、内側に配置した熱処理用ダ
イス10と角形管1の内面との間隙gは、 g >0.5tβ となっている。その他の構成は上記実施例と同様であ
る。
Heat treatment die 10 and outer surface molding die 2
The interval with 0 is set to be equal to the thickness of the thick portion 1A formed by the thickness increasing process. The gap g'between the outer surface forming die 20 and the outer surface of the rectangular tube 1 is usually smaller than the amount by which the tube wall is thickened to the outer surface side by thickening, that is, g '<0.5tβ. . Therefore, the gap g between the heat treatment die 10 arranged inside and the inner surface of the rectangular tube 1 is g> 0.5tβ. Other configurations are the same as those in the above embodiment.

【0040】図11、図12の実施例においては、角形
管1に圧縮力を作用させた状態で、加熱装置4が角形管
1を局部的に加熱して加熱部5を形成し、且つ角形管1
に沿って移動する。これにより、加熱部5に増肉が生じ
且つその後端が外面用成形ダイス20で冷却、固化され
ながら、その加熱部5が角形管1の長手方向に移動し、
連続的に増肉が行われる。この際、増肉によって外面側
に増肉しようとする加熱部5の管壁が外面用成形ダイス
20によって抑制され、その分内面側に増肉が生じる。
また、角形管の側壁に生じ勝ちな凹みは熱処理用ダイス
10で抑制される。かくして、外面側の寸法を外面用成
形ダイス20で規制しながら、凹みのない側壁を備えた
厚肉部1Aを形成することができる。また、得られた厚
肉部1Aは内外面を共にダイス面で規制されるため、き
わめて平滑となっている。増肉加工で形成された厚肉部
1Aは、その後、直ちに補助加熱装置9によって加熱さ
れ、熱処理が行われる。この場合においても、厚肉部1
A内面が熱処理用ダイス10で規制されているため、凹
みが生じることはなく、ゆがみの無い厚肉部を形成でき
る。
In the embodiment shown in FIGS. 11 and 12, the heating device 4 locally heats the rectangular tube 1 to form the heating portion 5 while the rectangular tube 1 is subjected to a compressive force, and Tube 1
Move along. As a result, the heating portion 5 moves in the longitudinal direction of the rectangular tube 1 while increasing the thickness of the heating portion 5 and cooling and solidifying the rear end of the heating portion 5 by the outer surface forming die 20.
The meat is continuously thickened. At this time, the pipe wall of the heating unit 5 which tends to increase in thickness to the outer surface side due to the increase in thickness is suppressed by the outer surface forming die 20, and accordingly, the thickness increases on the inner surface side.
Further, the heat treatment die 10 suppresses the recesses that are likely to occur on the side wall of the rectangular tube. Thus, it is possible to form the thick-walled portion 1A having the side wall without a recess while controlling the outer surface side dimension with the outer surface molding die 20. The thick portion 1A thus obtained is extremely smooth because both the inner and outer surfaces are regulated by the die surface. The thick portion 1A formed by the thickening process is then immediately heated by the auxiliary heating device 9 to be heat-treated. Even in this case, the thick portion 1
Since the inner surface of A is regulated by the heat treatment die 10, a dent does not occur, and a thick portion without distortion can be formed.

【0041】なお、図11、図12に示す実施例におい
ても、増肉を開始する位置及び/又は増肉を終了する位
置において、図8〜図10で説明したように増肉率を変
化させることで、傾斜面を形成し、しかもその際、増肉
部の外面が外面用成形ダイス20に接触した時点或いは
離れた時点で増肉率の変化比率を変更することにより、
一定勾配の傾斜面を形成することが可能である。
Note that, also in the embodiments shown in FIGS. 11 and 12, the thickness increase rate is changed as described with reference to FIGS. 8 to 10 at the position where the thickness increase starts and / or the position where the thickness increase ends. Thus, by forming an inclined surface, and at that time, by changing the change rate of the thickness increase rate at the time when the outer surface of the thickness increasing portion comes into contact with or separates from the outer surface forming die 20,
It is possible to form a slope with a constant slope.

【0042】更に、図11、図12に示す実施例では、
外面用成形ダイス20と角形管1の外面との間隙g′
を、g′<0.5tβ と設定し、増肉が角形管の内面
側に多く生じるように規制する構成としている。しかし
ながら、本発明は必ずしもこの構成に限らず、熱処理用
ダイス10と角形管1の内面との間隙gが、 0<g≦0.5tβ となるように設定し、増肉が内外面で均等に生じるか或
いは外面側で多く生じるようにしてもよい。この場合に
は、外面用成形ダイス20と角形管外面との間隙g′
は、 g′≧0.5tβ となる。この場合にも、加熱部5の増肉直後の部分を外
面用成形ダイス20で成形することで、平滑な外面を得
ることができる。
Further, in the embodiment shown in FIGS. 11 and 12,
A gap g ′ between the outer surface forming die 20 and the outer surface of the rectangular tube 1.
Is set to g '<0.5tβ, and the thickness is regulated so that the increase in the thickness increases on the inner surface side of the rectangular tube. However, the present invention is not necessarily limited to this configuration, and the gap g between the heat treatment die 10 and the inner surface of the rectangular tube 1 is set so as to satisfy 0 <g ≦ 0.5tβ, and the thickness increase is made uniform on the inner and outer surfaces. It may occur or may occur more frequently on the outer surface side. In this case, a gap g ′ between the outer surface forming die 20 and the outer surface of the rectangular pipe.
Is g ′ ≧ 0.5tβ. Also in this case, a smooth outer surface can be obtained by molding the portion of the heating unit 5 immediately after the thickness increase with the outer surface molding die 20.

【0043】以上の実施例はいずれも、増肉加工用の加
熱装置4の後ろに、熱処理用の補助加熱装置9を加熱装
置4と一緒に移動するように設けているが、本発明は必
ずしもこの構成に限らず、補助加熱装置9を加熱装置4
とは独立して移動する構成としてもよい。また、上記実
施例では、増肉加工と熱処理を並行して行う構成として
いるが、熱処理は必ずしも、増肉加工と並行して行う必
要はなく、増肉加工を終了した後、熱処理のみを行って
もよい。熱処理のみを単独に行う場合には、当然金属管
1に対して圧縮装置3による圧縮力を付与する必要はな
い。また、その場合、熱処理のための補助加熱装置9の
移動方向は図1における矢印C方向に限らず、その反対
方向としてもよい。更に、熱処理用の補助加熱装置9を
増肉加工用の加熱装置4と別に設ける必要はなく、加熱
装置4を熱処理に使用してもよい。また、厚肉部1Aの
熱処理を行うには、厚肉部1Aの全体を同時に加熱しう
る熱処理用加熱装置を用いて、全域を同時に加熱し、放
冷或いは強制冷却して熱処理するように変更してもよ
い。
In all of the above embodiments, the auxiliary heating device 9 for heat treatment is provided after the heating device 4 for thickening so as to move together with the heating device 4, but the present invention is not necessarily required. Not limited to this configuration, the auxiliary heating device 9 may be replaced by the heating device 4
It may be configured to move independently of. Further, in the above-mentioned embodiment, the structure is configured such that the thickness increasing process and the heat treatment are performed in parallel, but the heat treatment does not necessarily have to be performed in parallel with the thickness increasing process, and only the heat treatment is performed after the thickness increasing process is completed. May be. When the heat treatment alone is performed, it is not necessary to apply the compression force of the compression device 3 to the metal tube 1. In that case, the moving direction of the auxiliary heating device 9 for heat treatment is not limited to the arrow C direction in FIG. 1, but may be the opposite direction. Furthermore, it is not necessary to provide the auxiliary heating device 9 for heat treatment separately from the heating device 4 for thickening, and the heating device 4 may be used for heat treatment. Further, in order to perform the heat treatment of the thick portion 1A, a heating device for heat treatment capable of simultaneously heating the entire thick portion 1A is used, and the entire region is heated at the same time, and the heat treatment is performed by cooling or forced cooling. You may.

【0044】以上に角形管1に対する増肉加工及び熱処
理を行う場合を説明したが、本発明は角形管1に限定さ
れるものでなく、例えば、丸形管に対しても適用可能で
あることは言うまでもない。
The case where the thickening process and the heat treatment are performed on the rectangular tube 1 has been described above, but the present invention is not limited to the rectangular tube 1 and can be applied to a round tube, for example. Needless to say.

【0045】[0045]

【実施例】以下、具体的に増肉加工を行った例を示す。 〔実施例1〕 使用装置 図1に示す構成の増肉加工熱処理装置。各部仕様は次の
通り。 圧縮装置3:油圧シリンダ 加熱装置4:高周波加熱コイル(幅20mm) 冷却装置6:水噴射冷却方式 加熱幅(加熱装置4の先端から水吹き付け位置までの距
離):65mm 補助加熱装置9:高周波加熱コイル(幅50mm) 熱処理加熱部26の冷却方式:水噴射冷却方式 加熱装置4と補助加熱装置9の間隔:300mm 熱処理用ダイス10:外形264×264mm、長さ3
00mm
The following is an example of a specific example of a thickening process. [Example 1] Used device A thickening heat treatment device having the configuration shown in Fig. 1. The specifications of each part are as follows. Compressor 3: Hydraulic cylinder Heating device 4: High frequency heating coil (width 20 mm) Cooling device 6: Water injection cooling method Heating width (distance from tip of heating device 4 to water spraying position): 65 mm Auxiliary heating device 9: High frequency heating Coil (width 50 mm) Cooling system for heat treatment heating unit 26: water injection cooling system Distance between heating device 4 and auxiliary heating device 9: 300 mm Heat treatment die 10: external shape 264 x 264 mm, length 3
00 mm

【0046】 増肉加工および熱処理条件 供試角形管:300×300mm×12mmtの角形鋼
管 増肉率β:1.0(厚み12mmを24mmに増肉) 加熱部5の最高温度:1150±50°C 加熱装置4の移動速度W:0.45mm/s 圧縮装置3による圧縮力P:53,600kg (この結果圧縮手段3による押し込み速度V=0.45
mm/sとなる) 増肉加工速度(W+V):0.9mm/s 熱処理加熱部26の最高温度:950±50°C
Thickening processing and heat treatment conditions Test square tube: 300 × 300 mm × 12 mmt square steel tube Thickening rate β: 1.0 (thickness increased from 12 mm to 24 mm) Maximum temperature of heating part 5: 1150 ± 50 ° C moving speed W of heating device 4: 0.45 mm / s compression force P: 53,600 kg by the compression device 3 (as a result, pushing speed V = 0.45 by the compression means 3)
mm / s) Thickness increase processing speed (W + V): 0.9 mm / s Maximum temperature of heat treatment heating section 26: 950 ± 50 ° C

【0047】 増肉加工及び熱処理結果 上記した条件で増肉加工を行うと共に熱処理を行い、長
さ約250mmの厚肉部1Aを形成した。得られた厚肉
部1Aの厚みは約24mm(増肉率β=1.0)でほぼ
予定した値となっていた。また、外形寸法は311.8
×311.5mmであり、内外面にほぼ等しく増肉が生
じていた。この厚肉部1Aの内外面はいずれも平滑であ
り、じゃばらや小じわの無い良好な外観を備えていた。
得られた厚肉部の4つの平坦面における凹み量e〔図4
(b)参照〕を測定したところ、0.2〜0.7mmの
範囲内であり、きわめて小さいものであった。更に得ら
れた厚肉部1Aの機械的物性を測定したところ、表面硬
度はHv200以下、伸びは20%以上であった。
Thickening and Heat Treatment Results Under the above conditions, the thickening and heat treatment were performed to form a thick portion 1A having a length of about 250 mm. The thickness of the obtained thick portion 1A was about 24 mm (thickness increase ratio β = 1.0), which was almost the expected value. The external dimensions are 311.8.
The thickness was × 311.5 mm, and the inner and outer surfaces were almost equally thickened. The inner and outer surfaces of the thick portion 1A were both smooth, and had a good appearance without bellows or fine wrinkles.
Depression amount e on the four flat surfaces of the obtained thick portion [Fig.
[See (b)], it was in the range of 0.2 to 0.7 mm, which was extremely small. Further, when the mechanical properties of the obtained thick portion 1A were measured, the surface hardness was Hv 200 or less and the elongation was 20% or more.

【0048】〔比較例1〕熱処理用ダイスを取り外した
以外は、実施例1と同一条件で同一角形管に対して増肉
加工及び熱処理を行おうとしたところ、図13に示すよ
うに角形管1に対してじゃばら状の変形30を生じ、良
好な増肉が出来なかった。
Comparative Example 1 When an attempt was made to increase the thickness and heat treat the same rectangular tube under the same conditions as in Example 1 except that the heat treatment die was removed, as shown in FIG. On the other hand, a bellows-like deformation 30 was generated, and good thickness increase could not be achieved.

【0049】〔比較例2〕加熱部5の最高温度を130
0±50°Cとし、圧縮装置3による圧縮力Pを34,
500kgとした以外は、比較例1と同じ条件で増肉加
工及び熱処理を行い、長さ約250mmの厚肉部1Aを
形成した。得られた厚肉部1Aの厚みは約24mm(増
肉率β=1.0)でほぼ予定した値となっていた。この
厚肉部1Aの内外面はいずれも平滑であり、じゃばらや
小じわの無い良好な外観を備えていた。しかしながら、
得られた厚肉部の4つの平坦面における凹み量eを測定
したところ、1.2〜2.8mmであり、かなり大きく
なっていた。
[Comparative Example 2] The maximum temperature of the heating section 5 was set to 130.
0 ± 50 ° C., the compression force P by the compression device 3 is 34,
Thickening processing and heat treatment were performed under the same conditions as in Comparative Example 1 except that the weight was 500 kg to form a thick portion 1A having a length of about 250 mm. The thickness of the obtained thick portion 1A was about 24 mm (thickness increase ratio β = 1.0), which was almost the expected value. The inner and outer surfaces of the thick portion 1A were both smooth, and had a good appearance without bellows or fine wrinkles. However,
When the amount of depression e on the four flat surfaces of the obtained thick portion was measured, it was 1.2 to 2.8 mm, which was considerably large.

【0050】〔比較例3〕補助加熱装置9を動作させな
い以外は比較例2と同一条件で、増肉加工のみを行い、
長さ約250mmの厚肉部1Aを形成した。得られた厚
肉部1Aの厚みは約24mm(増肉率β=1.0)でほ
ぼ予定した値となっていた。この厚肉部1Aの内外面は
いずれも平滑であり、じゃばらや小じわの無い良好な外
観を備えていた。得られた厚肉部1Aの4つの平坦面に
おける凹み量eを測定したところ、0.5〜1.5mm
であり、比較例2よりは小さいが、実施例1に比べると
かなり大きくなっていた。更に、得られた厚肉部1Aの
機械的物性を測定したところ、表面硬度はHv350±
50、伸びは10±5%であり、熱処理を行っていない
ため、増肉加工による硬化の影響が出ていた。
[Comparative Example 3] Under the same conditions as in Comparative Example 2 except that the auxiliary heating device 9 was not operated, only thickening processing was performed.
A thick portion 1A having a length of about 250 mm was formed. The thickness of the obtained thick portion 1A was about 24 mm (thickness increase ratio β = 1.0), which was almost the expected value. The inner and outer surfaces of the thick portion 1A were both smooth, and had a good appearance without bellows or fine wrinkles. When the amount of depression e in the four flat surfaces of the obtained thick portion 1A was measured, it was 0.5 to 1.5 mm.
Although smaller than Comparative Example 2, it was considerably larger than that of Example 1. Furthermore, when the mechanical properties of the obtained thick portion 1A were measured, the surface hardness was Hv350 ±
50, the elongation was 10 ± 5%, and since no heat treatment was performed, there was an effect of hardening due to the thickening process.

【0051】〔実施例2〕 使用装置 実施例1と同じ 増肉加工条件 供試角形管:300×300mm×12mmtの角形鋼
管 増肉率β:1.0(厚み12mmを24mmに増肉) 加熱部最高温度:1300±50°C 加熱手段4の移動速度W:0.9mm/s 圧縮手段3による圧縮力P:38,000kg (この結果圧縮手段3による押し込み速度V=0.9m
m/sとなる) 増肉加工速度(=W+V):1.8mm/s 熱処理加熱部26の最高温度:1000°C
[Example 2] Equipment used Same as in Example 1 Conditions for increasing wall thickness Test square tube: Square steel tube of 300 x 300 mm x 12 mmt Thickness increase rate β: 1.0 (12 mm thickness was increased to 24 mm) Heating Part maximum temperature: 1300 ± 50 ° C. Moving speed W of heating means 4: 0.9 mm / s Compression force P by compression means 3: 38,000 kg (as a result, pushing speed V = 0.9 m by compression means 3)
m / s) Thickness increase processing speed (= W + V): 1.8 mm / s Maximum temperature of heat treatment heating part 26: 1000 ° C

【0052】 増肉加工結果 上記した条件で増肉加工を行うと共に熱処理を行い、長
さ約250mmの厚肉部1Aを形成した。得られた厚肉
部1Aの厚みは約24mm(増肉率β=1.0)でほぼ
予定した値となっていた。また、外形寸法は312.5
×311.6mmであり、内外面にほぼ等しく増肉が生
じていた。この厚肉部1Aの内外面はいずれも平滑であ
り、じゃばらや小じわの無い良好な外観を備えていた。
得られた厚肉部の4つの平坦面における凹み量eは、
0.2〜0.7mmの範囲内であり、きわめて小さいも
のであった。このように、実施例2では実施例1よりも
増肉加工速度及び熱処理速度を2倍としているが、実施
例1のものとほぼ等しい外形の厚肉部1Aを形成でき
た。なお、得られた厚肉部1Aの機械的物性を測定した
ところ、表面硬度はHv200以下、伸びは20%以上
であり、熱処理による機械的特性の改善が十分行われて
いた。
Thickening processing result Under the above-mentioned conditions, the thickening processing and the heat treatment were performed to form the thick portion 1A having a length of about 250 mm. The thickness of the obtained thick portion 1A was about 24 mm (thickness increase ratio β = 1.0), which was almost the expected value. The external dimensions are 312.5.
The thickness was × 311.6 mm, and the inner and outer surfaces were almost equally thickened. The inner and outer surfaces of the thick portion 1A were both smooth, and had a good appearance without bellows or fine wrinkles.
The amount of depression e on the four flat surfaces of the obtained thick portion is
It was in the range of 0.2 to 0.7 mm, which was extremely small. As described above, in Example 2, the thickening processing rate and the heat treatment rate were doubled as compared with Example 1, but the thick portion 1A having an outer shape substantially equal to that of Example 1 could be formed. When the mechanical properties of the obtained thick portion 1A were measured, the surface hardness was Hv 200 or less and the elongation was 20% or more, and the mechanical properties were sufficiently improved by heat treatment.

【0053】[0053]

【発明の効果】以上に説明したように、本発明方法によ
れば、増肉加工すべき金属管内に熱処理用ダイスを挿入
しておき、金属管に対する増肉加工によってその熱処理
用ダイスの外側に厚肉部を形成し、且つその状態で厚肉
部の熱処理を行っているので、増肉加工時の加熱、冷
却、及び熱処理時の加熱、冷却によって厚肉部の断面に
ゆがみが生じようとしても、厚肉部内面を熱処理用ダイ
スが拘束して望ましくないゆがみを防止でき、このた
め、所定の断面形状の且つ所望の熱処理を施された厚肉
部を形成できるという効果が得られる。また、熱処理時
のゆがみを熱処理用ダイスによって強制的に防止できる
ため、熱処理時における加熱速度、冷却速度等を調整し
てゆがみの防止を図る必要がなく、このため、必要な熱
処理に応じた所望の加熱速度、冷却速度等を採用でき、
良好な熱処理を施した厚肉部を生産性良く製造できると
いう効果も得られる。
As described above, according to the method of the present invention, the heat treatment die is inserted into the metal pipe to be thickened, and the metal pipe is thickened to the outside of the heat treatment die. Since the thick part is formed and the thick part is heat-treated in that state, it is likely that the cross-section of the thick part will be distorted by heating and cooling during thickening and heating and cooling during heat treatment. In addition, the heat treatment die can restrain the inner surface of the thick portion to prevent undesired distortion. Therefore, the thick portion having a predetermined cross-sectional shape and subjected to the desired heat treatment can be formed. Further, since the distortion during the heat treatment can be forcibly prevented by the heat treatment die, it is not necessary to adjust the heating rate, the cooling rate, etc. during the heat treatment to prevent the distortion. The heating rate, cooling rate, etc. of
It is also possible to obtain an effect that a thick portion that has been subjected to favorable heat treatment can be manufactured with high productivity.

【0054】更に、熱処理用ダイスは、金属管に増肉を
生じさせる部分における断面でのゆがみを阻止するのみ
ならず、増肉加工時の不安定な変形、例えば長手方向に
生じ勝ちなじゃばら状の変形を防止する効果も有してお
り、このため、本発明は、良好な増肉加工を可能とする
増肉加工条件(例えば、加熱部の温度、圧縮力、冷却速
度、増肉加工速度等)の範囲を広げることが可能とな
り、増肉加工速度を上げて生産性を向上させるとか、増
肉率を大きく設定できる等の効果も得られる。
Further, the heat treatment die not only prevents the cross-section from being distorted in the portion where the metal pipe is thickened, but also causes an unstable deformation during the thickening process, for example, a bellows shape which tends to occur in the longitudinal direction. The present invention also has the effect of preventing the deformation of the steel sheet, and therefore the present invention provides the thickening processing conditions (for example, the temperature of the heating portion, the compressive force, the cooling speed, the thickening processing speed) that enable the favorable thickening processing. It is possible to widen the range of (1), etc., and it is possible to obtain the effects of increasing the thickness increase processing speed to improve productivity, and setting a large thickness increase rate.

【0055】ここで、厚肉部の熱処理を行う方法とし
て、厚肉部の小領域を補助加熱装置によって、所望の熱
処理温度に加熱して熱処理加熱部を形成し、該熱処理加
熱部を厚肉部の長手方向に相対的に移動させる方法を採
用すると、比較的小型の補助加熱装置によって厚肉部を
所望温度に加熱して熱処理を行うことができ、設備費を
削減できるという効果が得られる。また、その熱処理動
作を増肉加工と並行して行うことが可能であり、増肉加
工と熱処理とを並行して行うと、生産性を向上できると
いう効果が得られる。
Here, as a method of heat-treating the thick-walled portion, a small area of the thick-walled portion is heated to a desired heat-treatment temperature by an auxiliary heating device to form a heat-treated heated portion, and the heat-treated heated portion is thickened. If a method of relatively moving in the longitudinal direction of the portion is adopted, it is possible to heat the thick portion to a desired temperature by a relatively small auxiliary heating device and perform heat treatment, and it is possible to reduce the facility cost. . Further, the heat treatment operation can be performed in parallel with the thickness increasing process, and if the thickness increasing process and the heat treatment are performed in parallel, the effect of improving productivity can be obtained.

【0056】ここで、前記熱処理用ダイスを増肉加工す
べき金属管内にセットした状態での前記熱処理用ダイス
と増肉前の角形管内面との間の間隙gを、 g≒0.5tβ と設定しておくと、増肉加工による増肉が管壁の内外面
にほぼ等しく生じ且つその増肉加工で形成した厚肉部の
内面が熱処理用ダイス外面に軽く接触するか或いは両者
間に微小な隙間が残る状態となり、この状態で熱処理し
た後、熱処理用ダイスを厚肉部内から引き抜く作業を容
易とすることができるという効果が得られる。
Here, the gap g between the heat treatment die and the inner surface of the rectangular pipe before the metal thickening is set in the state where the heat treatment die is set in the metal pipe to be thickened, and g≈0.5tβ If set, the thickness increase due to the thickness increase process will occur almost equally on the inner and outer surfaces of the pipe wall, and the inner surface of the thick part formed by the thickness increase will lightly contact the outer surface of the heat treatment die or there will be a small amount between them. A large gap remains, and after the heat treatment in this state, it is possible to easily remove the heat treatment die from the thick portion.

【0057】また、この間隙gを、 0<g<0.5tβ と設定しておくと、増肉加工時に熱処理用ダイスが内面
用成形ダイスとして作用して管壁の内面を所定形状に成
形でき、断面におけるゆがみを防止するのみならず、内
面を平滑にすることができるという効果が得られる。
Further, if the gap g is set to 0 <g <0.5tβ, the heat treatment die acts as an inner surface forming die at the time of thickening, so that the inner surface of the pipe wall can be formed into a predetermined shape. In addition to preventing distortion in the cross section, the inner surface can be smoothed.

【0058】上記した増肉加工を行うに当たって、増肉
加工の開始時には増肉率を金属管の長手方向位置に応じ
て一定比率で増加させ、金属管内面が熱処理用ダイスに
接触した時点以降はその増肉率の増加比率を約半分に低
下させ、所定の増肉率に達した後は増肉率を一定に保っ
て増肉加工を行うことができ、この方法を採用すると、
増肉加工で形成される厚肉部の増肉開始側端部に、非増
肉部から所定厚さの厚肉部に到る一定勾配の斜面を形成
することができ、応力集中の生じにくい増肉部を形成で
きるという効果が得られる。
In carrying out the above-described thickening process, at the start of the thickening process, the thickness increasing rate is increased at a constant rate according to the longitudinal position of the metal pipe, and after the time when the inner surface of the metal pipe contacts the heat treatment die. The increase rate of the thickness increase rate is reduced to about half, and after reaching a predetermined thickness increase rate, the thickness increase rate can be kept constant and the thickness increase processing can be performed.
At the thickening start side end of the thick portion formed by the thickening process, a slope with a constant gradient can be formed from the non-thickened portion to the thick portion having a predetermined thickness, and stress concentration is less likely to occur. The effect that the thickened portion can be formed is obtained.

【0059】また、増肉加工の終了時には増肉率を金属
管の長手方向位置に応じて一定比率で減少させ、金属管
内面が熱処理用ダイスに非接触となった時点以降はその
増肉率の減少比率を約倍として減少させることもでき、
その場合には、増肉加工で形成される厚肉部の増肉終了
側端部に、所定厚さの厚肉部から非増肉部に到る一定勾
配の斜面を形成することができ、応力集中に生じにくい
増肉部を形成できるという効果が得られる。
Further, at the end of the thickness increasing process, the thickness increasing rate is reduced at a constant rate according to the longitudinal position of the metal tube, and after the time when the inner surface of the metal tube is not in contact with the heat treatment die, the thickness increasing rate is It is also possible to reduce the reduction ratio of
In that case, a slope having a constant gradient from the thick portion having a predetermined thickness to the non-thickened portion can be formed at the end portion on the thickening end side of the thick portion formed by the thickening process, It is possible to obtain an effect that it is possible to form a thickened portion that is unlikely to occur in stress concentration.

【0060】更に、金属管に形成する前記加熱部の外側
に外面用成形ダイスを配置する構成とすると、増肉した
管壁の外面を成形して平滑にすることができ、また、こ
の外面用成形ダイスで管壁の外面側に生じる増肉量の一
部を抑制し、その分内面側を増肉させることが可能とな
り、外面側の増肉量を必要に応じ内面側よりも少なくす
ることができるという効果が得られる。
Further, when the outer surface forming die is arranged outside the heating portion formed on the metal tube, the outer surface of the thickened tube wall can be formed to be smooth, and the outer surface forming die can be formed. It is possible to suppress a part of the wall thickness increase on the outer surface side of the pipe wall with the molding die, and to increase the inner surface side portion by that amount, and to reduce the wall thickness increase on the outer surface side as compared to the inner surface side as necessary. The effect of being able to do is obtained.

【0061】本発明装置は、増肉加工すべき金属管内
に、増肉加工によって形成される厚肉部の内側に位置す
るように挿入され、前記厚肉部の長さ以上の長さを有す
る熱処理用ダイスと、前記金属管に長手方向の圧縮力を
作用させる圧縮装置と、前記金属管の長手方向の小領域
を加熱して赤熱状態の加熱部を形成する加熱装置と、そ
の加熱部の一端を冷却する冷却装置と、前記加熱装置及
び冷却装置を、角形管に対して相対的に移動させる移動
装置と、前記加熱装置の後ろに該加熱装置と一緒に移動
するように設けられ、増肉加工によって形成された厚肉
部の小領域を、熱処理を行う温度に加熱して熱処理加熱
部を形成する補助加熱装置とを有する構成としたことに
より、加熱装置が金属管を局部的に加熱して増肉を生じ
させ且つその金属管に相対的に移動して厚肉部を形成し
てゆく増肉加工動作と並行して、その厚肉部の小領域を
補助加熱装置が加熱して熱処理加熱部を形成し、且つそ
の補助加熱装置が金属管に対して相対的に移動して前記
熱処理加熱部を厚肉部の長手方向に相対的に移動させ、
厚肉部の全域の熱処理を行うことができ、しかも、それ
らの増肉加工及び熱処理は金属管内に熱処理用ダイスが
存在する状態で行われるため断面形状にゆがみを生じる
ことがなく、断面形状の良好な且つ熱処理により機械的
特性を改善した厚肉部を効率良く製造できるという効果
を有している。また、単一の移動装置によって増肉用の
加熱装置と熱処理用の補助加熱装置とを金属管に相対的
に移動させることができ、装置構成を簡略化できるとい
う効果も有している。
The device of the present invention is inserted into a metal pipe to be thickened so as to be located inside a thick portion formed by the thickening, and has a length equal to or longer than the length of the thick portion. A die for heat treatment, a compression device that applies a compressive force in the longitudinal direction to the metal pipe, a heating device that heats a small region in the longitudinal direction of the metal pipe to form a heating part in a red heat state, and a heating part of the heating part. A cooling device for cooling one end, a moving device for moving the heating device and the cooling device relative to the rectangular tube, and a heating device provided behind the heating device so as to move together with the heating device. The heating device locally heats the metal pipe by having a configuration in which a small region of the thick portion formed by meat processing is heated to a temperature for heat treatment to form a heat treatment heating portion. To increase the thickness of the metal pipe Auxiliary heating device heats a small area of the thick portion to form a heat treatment heating portion in parallel with the thickening operation of moving relatively to form the thick portion, and the auxiliary heating device. Is relatively moved with respect to the metal pipe to relatively move the heat treatment heating part in the longitudinal direction of the thick part,
It is possible to perform heat treatment on the entire thick-walled portion, and since those thickening processing and heat treatment are performed in the state where the heat treatment die exists in the metal pipe, there is no distortion in the cross-sectional shape, It has an effect of being able to efficiently manufacture a thick portion which is good and has improved mechanical properties by heat treatment. Further, the heating device for increasing the thickness and the auxiliary heating device for the heat treatment can be relatively moved to the metal tube by a single moving device, which also has the effect of simplifying the device configuration.

【0062】本発明の対象とする金属管を角形管とする
と、増肉加工及び熱処理時において平坦な側壁に生じ勝
ちな凹みの発生を防止でき、平坦度の良い厚肉部を形成
できるという効果が得られる。
When the metal tube to which the present invention is applied is a rectangular tube, it is possible to prevent the occurrence of dents that tend to occur on the flat side wall during thickening and heat treatment, and to form a thick wall portion with good flatness. Is obtained.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明方法の実施に用いる増肉加工熱処理装置
の好適な例を示す概略断面図
FIG. 1 is a schematic cross-sectional view showing a preferred example of a thickening heat treatment apparatus used for carrying out the method of the present invention.

【図2】(a)、(b)はそれぞれ、図1のA−A矢視
断面図、B−B矢視断面図
2A and 2B are cross-sectional views taken along arrows AA and BB of FIG. 1, respectively.

【図3】図1の実施例における増肉加工部分の拡大断面
FIG. 3 is an enlarged cross-sectional view of a thickened portion in the embodiment of FIG.

【図4】(a)は本発明の実施例で形成した厚肉部1A
の断面図 (b)は熱処理用ダイスを用いないで形成した厚肉部1
Aの断面図
FIG. 4A is a thick portion 1A formed in the embodiment of the present invention.
A cross-sectional view (b) is a thick portion 1 formed without using a heat treatment die.
Sectional view of A

【図5】(a)、(b)はそれぞれ、熱処理用ダイスの
変形例を示す図2(a)と同一部分の断面図
5 (a) and 5 (b) are sectional views of the same portion as FIG. 2 (a) showing a modified example of the heat treatment die.

【図6】本発明の他の実施例における増肉加工部分の拡
大断面図
FIG. 6 is an enlarged cross-sectional view of a thickened portion in another embodiment of the present invention.

【図7】(a)は通常に増肉加工を行った場合の増肉開
始部分を示す概略断面図 (b)は好ましい傾斜面を有する増肉開始部分を示す概
略断面図
FIG. 7 (a) is a schematic cross-sectional view showing a thickness-increasing start portion in a case where normal thickness-increasing processing is performed, and FIG. 7 (b) is a schematic cross-sectional view showing a thickness increase starting portion having a preferable inclined surface.

【図8】(a)は熱処理用ダイスが無いものと想定して
増肉率を一定比率で増加した場合の増肉開始部分を示す
概略断面図 (b)は熱処理用ダイスが有る状態で増肉率を一定比率
で増加した場合の増肉開始部分を示す概略断面図
FIG. 8 (a) is a schematic cross-sectional view showing a portion where the thickness increase starts at a constant rate assuming that there is no heat treatment die, and FIG. 8 (b) shows an increase with the heat treatment die. Schematic cross-sectional view showing the portion where the meat increase starts when the meat ratio is increased at a constant ratio

【図9】本発明の一実施例を説明するもので、(a)は
熱処理用ダイスが無いものと想定して増肉率を一定比率
で増加し、位置Pからその比率を変化させた場合の増肉
開始部分を示す概略断面図 (b)は熱処理用ダイスが有る状態で増肉率を一定比率
で増加し、位置Pからその比率を変化させた場合の増肉
開始部分を示す概略断面図 (c)はこの実施例で得た厚肉部の増肉開始部分を示す
概略断面図
9A and 9B are views for explaining an embodiment of the present invention, in which (a) is a case where the thickness increase rate is increased at a constant rate on the assumption that there is no heat treatment die and the rate is changed from the position P. FIG. (B) is a schematic cross-sectional view showing the thickness increase starting portion in the case where the heat treatment die is provided, the thickness increasing rate is increased at a constant ratio, and the thickness increasing start portion is changed from the position P. FIG. 6C is a schematic cross-sectional view showing the thickening start portion of the thick portion obtained in this example.

【図10】本発明の他の実施例を示すもので、熱処理用
ダイスが有る状態で増肉率を一定比率で減少させ、位置
Qからその比率を変化させた場合の増肉終了部分を示す
概略断面図
FIG. 10 shows another embodiment of the present invention, showing a portion where the thickness increase ends when the rate of increase in thickness is reduced at a constant ratio with the heat treatment die and the ratio is changed from the position Q. Schematic cross section

【図11】本発明方法の実施に用いる増肉加工熱処理装
置の他の例を示す概略断面図
FIG. 11 is a schematic cross-sectional view showing another example of the thickening heat treatment apparatus used for carrying out the method of the present invention.

【図12】図10に示す他の実施例における増肉加工部
分の拡大断面図
FIG. 12 is an enlarged cross-sectional view of a thickened portion in another embodiment shown in FIG.

【図13】比較例1で増肉加工した角形管を示す概略断
面図
FIG. 13 is a schematic cross-sectional view showing a square tube having a wall thickness increased in Comparative Example 1.

【符号の説明】[Explanation of symbols]

1 角形管 1a 側壁(平坦な管壁) 1b コーナー壁 1A 厚肉部 2 固定装置 3 圧縮装置 4 加熱装置 5 加熱部 6 冷却装置 7 冷却媒体 8 移動装置 9 補助加熱装置 10 熱処理用ダイス 10a 側壁ダイス面 10b コーナーダイス面 12 凹み DESCRIPTION OF SYMBOLS 1 Rectangular tube 1a Side wall (flat tube wall) 1b Corner wall 1A Thick part 2 Fixing device 3 Compressor 4 Heating device 5 Heating part 6 Cooling device 7 Cooling medium 8 Moving device 9 Auxiliary heating device 10 Heat treatment die 10a Side wall die Surface 10b Corner die surface 12 Recess

───────────────────────────────────────────────────── フロントページの続き (72)発明者 皆川 次夫 神奈川県川崎市川崎区殿町2丁目17番8号 第一高周波工業株式会社内 (72)発明者 福田 章 大阪府大阪市西区阿波座1丁目5番16号 大和ハウス工業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tsuguo Minagawa, 2-17-8, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Daiichi Kogyo Kogyo Co., Ltd. (72) Inventor, Akira Fukuda, 1-chome, Awaza, Nishi-ku, Osaka-shi, Osaka No. 5-16 Daiwa House Industry Co., Ltd.

Claims (10)

【特許請求の範囲】[Claims] 【請求項1】 増肉加工すべき金属管内に、増肉加工に
よって形成される厚肉部の内側に位置するように、その
厚肉部の長さ以上の長さを有する熱処理用ダイスをあら
かじめ挿入しておき、この状態で、前記金属管の長手方
向の小領域を加熱装置で局部的に加熱して赤熱状態の加
熱部を形成し、該加熱部を金属管の長手方向に相対的に
移動させながら該加熱部に金属管の長手方向の圧縮力を
付与して順次増肉させ、且つ前記加熱部の後端部分を増
肉直後に冷却することによって、金属管を連続的に増肉
させて、前記熱処理用ダイスの外側に厚肉部を形成し、
その後、その厚肉部の内側に熱処理用ダイスを位置させ
た状態で前記厚肉部を熱処理することを特徴とする金属
管の増肉加工熱処理方法。
1. A heat treatment die having a length equal to or greater than the length of the thick portion is previously provided in the metal pipe to be thickened so as to be located inside the thick portion formed by the thickening process. In this state, a small area in the longitudinal direction of the metal tube is locally heated by a heating device in this state to form a heating section in a red heat state, and the heating section is relatively moved in the longitudinal direction of the metal tube. The metal tube is continuously thickened by applying a compressive force in the longitudinal direction of the metal tube to the heating part while moving to sequentially increase the thickness and cooling the rear end portion of the heating part immediately after the thickness increase. To form a thick portion on the outside of the heat treatment die,
After that, the thick-walled portion is heat-treated while the heat-treating die is positioned inside the thick-walled portion.
【請求項2】 前記厚肉部の小領域を補助加熱装置によ
って、所望の熱処理温度に加熱して熱処理加熱部を形成
し、該熱処理加熱部を厚肉部の長手方向に相対的に移動
させることにより、前記厚肉部の熱処理を行うことを特
徴とする請求項1記載の金属管の増肉加工熱処理方法。
2. A small area of the thick portion is heated to a desired heat treatment temperature by an auxiliary heating device to form a heat treatment heating portion, and the heat treatment heating portion is relatively moved in the longitudinal direction of the thick portion. The heat treatment method for increasing the thickness of a metal pipe according to claim 1, wherein the heat treatment is performed on the thick portion.
【請求項3】 金属管に対する増肉加工操作と、その増
肉加工によって形成された厚肉部の熱処理操作とを、並
行して行うことを特徴とする請求項2記載の金属管の増
肉加工熱処理方法。
3. The thickening process for a metal pipe according to claim 2, wherein the thickening process operation for the metal pipe and the heat treatment process for the thick portion formed by the thickening process are performed in parallel. Processing heat treatment method.
【請求項4】 前記熱処理用ダイスを増肉加工すべき金
属管内にセットした状態での前記熱処理用ダイスと増肉
前の金属管内面との間の間隙gを、増肉前の管壁の肉厚
t、金属管に生じさせる増肉率βに対して、 g≒0.5tβ となるように設定することを特徴とする請求項1から3
のいずれか1項に記載の金属管の増肉加工熱処理方法。
4. The gap g between the heat treatment die and the inner surface of the metal pipe before the thickness increase is set in the state where the heat treatment die is set in the metal pipe to be thickened, and 4. The thickness t and the thickness increase rate β generated in the metal pipe are set so that g≈0.5tβ.
The method for thickening and heat treating a metal tube according to any one of 1.
【請求項5】 前記熱処理用ダイスを増肉加工すべき金
属管内にセットした状態での前記熱処理用ダイスと増肉
前の金属管内面との間の間隙gを、増肉前の管壁の肉厚
t、金属管に生じさせる増肉率βに対して、 0<g<0.5tβ となるように設定することを特徴とする請求項1から3
のいずれか1項に記載の金属管の増肉加工熱処理方法。
5. The gap g between the heat treatment die and the inner surface of the metal pipe before the thickness increase in a state where the heat treatment die is set in the metal pipe to be subjected to the thickness increase processing, The thickness t and the thickness increase ratio β generated in the metal pipe are set so that 0 <g <0.5tβ.
The method for thickening and heat treating a metal tube according to any one of 1.
【請求項6】 請求項5に記載の金属管の増肉加工熱処
理方法において、増肉加工の開始時には増肉率を金属管
の長手方向位置に応じて一定比率で増加させ、金属管内
面が熱処理用ダイスに接触した時点以降はその増肉率の
増加比率を約半分に低下させ、所定の増肉率に達した後
は増肉率を一定に保って増肉加工を行うことを特徴とす
る金属管の増肉加工熱処理方法。
6. The method of heat treatment for increasing the thickness of a metal pipe according to claim 5, wherein at the start of the thickness increasing process, the increase ratio of the thickness is increased at a constant rate according to the longitudinal position of the metal pipe, After the point of contact with the heat treatment die, the increase rate of the thickness increase rate is reduced to about half, and after reaching the predetermined thickness increase rate, the thickness increase rate is kept constant and the thickness increase processing is performed. Metal tube thickening heat treatment method.
【請求項7】 請求項5又は6に記載の金属管の増肉加
工熱処理方法において、増肉加工の終了時には増肉率を
金属管の長手方向位置に応じて一定比率で減少させ、金
属管内面が熱処理用ダイスに非接触となった時点以降は
その増肉率の減少比率を約倍として減少させることを特
徴とする金属管の増肉加工熱処理方法。
7. The metal pipe thickening heat treatment method according to claim 5 or 6, wherein at the end of the metal thickening process, the metal thickening rate is reduced at a constant rate according to the longitudinal position of the metal pipe. A heat treatment method for increasing the thickness of a metal tube, characterized in that after the surface is not in contact with the heat treatment die, the reduction rate of the increase rate is reduced by about twice.
【請求項8】 更に、金属管に増肉加工のために形成す
る加熱部の外側に外面用成形ダイスを配置し、増肉によ
って外側に変形する管壁の外面位置を前記外面用成形ダ
イスによって規制することを特徴とする請求項1から5
のいずれか1項に記載の金属管の増肉加工熱処理方法。
8. An outer surface forming die is arranged outside a heating part formed for increasing the thickness of the metal pipe, and the outer surface position of the pipe wall which is deformed outward by increasing the thickness is determined by the outer surface forming die. It is restricted, It is characterized by the above-mentioned.
The method for thickening and heat treating a metal tube according to any one of 1.
【請求項9】 前記金属管が角形管であることを特徴と
する請求項1から8のいずれか1項に記載の金属管の増
肉加工熱処理方法。
9. The method of heat treatment for increasing the thickness of a metal tube according to claim 1, wherein the metal tube is a rectangular tube.
【請求項10】 増肉加工すべき金属管内に、増肉加工
によって形成される厚肉部の内側に位置するように挿入
され、前記厚肉部の長さ以上の長さを有する熱処理用ダ
イスと、前記金属管に長手方向の圧縮力を作用させる圧
縮装置と、前記金属管の長手方向の小領域を加熱して赤
熱状態の加熱部を形成する加熱装置と、その加熱部の一
端を冷却する冷却装置と、前記加熱装置及び冷却装置
を、角形管に対して相対的に移動させる移動装置と、前
記加熱装置の後ろに該加熱装置と一緒に移動するように
設けられ、増肉加工によって形成された厚肉部の小領域
を、熱処理を行う温度に加熱して熱処理加熱部を形成す
る補助加熱装置とを有する金属管の増肉加工熱処理装
置。
10. A heat treatment die which is inserted into a metal pipe to be thickened so as to be located inside a thick portion formed by the thickening and has a length equal to or greater than the length of the thick portion. A compression device that applies a compressive force in the longitudinal direction to the metal pipe, a heating device that heats a small region in the longitudinal direction of the metal pipe to form a heating portion in a red heat state, and one end of the heating portion is cooled. Cooling device, a moving device for moving the heating device and the cooling device relative to the rectangular tube, and a moving device provided behind the heating device so as to move together with the heating device. An apparatus for thickening and heat treating a metal tube, comprising: an auxiliary heating device that heats a small region of the formed thick portion to a temperature for heat treatment to form a heat treatment heating portion.
JP25729095A 1995-09-11 1995-09-11 Metal tube thickening heat treatment method and apparatus Expired - Fee Related JP2999698B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP25729095A JP2999698B2 (en) 1995-09-11 1995-09-11 Metal tube thickening heat treatment method and apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP25729095A JP2999698B2 (en) 1995-09-11 1995-09-11 Metal tube thickening heat treatment method and apparatus

Publications (2)

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JPH0976011A true JPH0976011A (en) 1997-03-25
JP2999698B2 JP2999698B2 (en) 2000-01-17

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107931499A (en) * 2017-11-23 2018-04-20 重庆大学 Control forms the electric current concurrent heating formula electricity upsetting method and device of even and fineization mixing crystal boundary
JPWO2022075026A1 (en) * 2020-10-05 2022-04-14

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107931499A (en) * 2017-11-23 2018-04-20 重庆大学 Control forms the electric current concurrent heating formula electricity upsetting method and device of even and fineization mixing crystal boundary
CN107931499B (en) * 2017-11-23 2019-06-28 重庆大学 Control forms the electric current concurrent heating formula electricity upsetting method and device of even refinement mixing crystal boundary
JPWO2022075026A1 (en) * 2020-10-05 2022-04-14
WO2022075026A1 (en) * 2020-10-05 2022-04-14 Jfeスチール株式会社 Rectangular steel pipe and production method therefor, and building structure

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