JP3328795B2 - Manufacturing method of tapered steel pipe - Google Patents
Manufacturing method of tapered steel pipeInfo
- Publication number
- JP3328795B2 JP3328795B2 JP03920496A JP3920496A JP3328795B2 JP 3328795 B2 JP3328795 B2 JP 3328795B2 JP 03920496 A JP03920496 A JP 03920496A JP 3920496 A JP3920496 A JP 3920496A JP 3328795 B2 JP3328795 B2 JP 3328795B2
- Authority
- JP
- Japan
- Prior art keywords
- steel pipe
- strength
- processing
- tapered
- tapered steel
- 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.)
- Expired - Lifetime
Links
Landscapes
- Heat Treatment Of Steel (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、照明塔などに利用
されるテーパー鋼管において、鋼管全体を加熱しながら
ロールを押し込み、テーパー加工することにより、剛性
に優れたテーパー鋼管を製造する方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tapered steel pipe having excellent rigidity by pressing a roll while heating the entire steel pipe and performing taper processing on the tapered steel pipe used for a lighting tower or the like. It is.
【０００２】[0002]
【従来の技術】テーパー鋼管は、主に高速道路の照明塔
などに使用されている。その製造方法については、従来
は、鋼板を台形に剪断し、それを溶接することによりテ
ーパー鋼管を製造する方法（板巻き法）や、冷間におい
てロール成形加工等によりテーパー鋼管を製造する方法
（例えば、特開昭５６−１６０８２９号公報）が用いら
れてきている。2. Description of the Related Art Tapered steel pipes are mainly used for highway lighting towers and the like. Conventionally, a method of manufacturing a tapered steel pipe by shearing a steel sheet into a trapezoid and welding it (plate winding method), or a method of manufacturing a tapered steel pipe by cold roll forming or the like ( For example, JP-A-56-160829 has been used.
【０００３】[0003]
【発明が解決しようとする課題】上記の方法うち、前者
（板巻き法）においては、板の大きさに限界があるた
め、多くの連結部により短いテーパー鋼管をつなぎ合わ
せることで長尺のテーパー鋼管を製造することになる。
従って、その連結のための工程が増えてしまうという問
題がある。また、板巻きのために、強度はそれぞれの管
で長手方向に対して均一となり、それらをつなげると鋼
管全長のどの部分においても強度分布が同一となる。テ
ーパー鋼管では、先端の径の細い部分での断面積が減少
するため、耐えられる荷重（剛性）が元径に比べて低く
なるので、先端部の強度を得るためには高強度材を使用
しなければならず、コスト的にも高いものとなる。仮
に、先端部のところで強度のあるテーパー鋼管をつなげ
たとしても、その継ぎ目部分での急激な強度の違いによ
り、応力集中が起きて破断の原因となる。Among the above methods, in the former method (plate winding method), since the size of the plate is limited, a long taper steel pipe is connected to many connecting portions to connect a short taper steel pipe. Steel pipe will be manufactured.
Therefore, there is a problem that the number of steps for the connection increases. In addition, because of the plate winding, the strength becomes uniform in the longitudinal direction in each pipe, and when they are connected, the strength distribution becomes the same in any part of the entire length of the steel pipe. In a tapered steel pipe, the cross-sectional area at the narrow end of the tip is reduced, so the load (rigidity) that can be endured is lower than the original diameter, so use a high-strength material to obtain the strength of the tip. The cost must be high. Even if a strong tapered steel pipe is connected at the tip, stress concentration occurs due to a sudden difference in strength at the joint, which causes breakage.
【０００４】一方、後者（冷間加工法）においては、加
工硬化が急激に起こりすぎてしまうために長尺のテーパ
ー鋼管の製造はできず、やはり連結部の多いものとなっ
てしまう。また、この加工硬化により伸びの急激な低下
が起こるため、照明柱として使用するために必要な二次
加工ができず、先端部で二次加工をすると破断してしま
うという問題点を有している。On the other hand, in the latter case (cold working method), a long tapered steel pipe cannot be manufactured because work hardening occurs too rapidly, so that there are still many joints. In addition, since the work hardening causes a sharp decrease in elongation, the secondary processing required for use as a lighting column cannot be performed, and there is a problem that the secondary processing at the tip portion breaks. I have.
【０００５】[0005]
【課題を解決するための手段】本発明は、上記従来技術
の問題点を解決するためになされたもので、その要旨と
するところは、鋼管全体を１００℃〜その材料のＡｃ1
変態点までの間の任意温度にて加熱しながらロールを押
し込み、テーパー加工することにより、鋼管長手方向に
対して元径部から先端径部の間で徐々に強度を向上さ
せ、鋼管全体の剛性を向上させることを特徴とするテー
パー鋼管の製造法にある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and the gist of the present invention is that the entire steel pipe is heated at 100 ° C. to Ac 1 of the material.
The roll is pushed in while heating at an arbitrary temperature up to the transformation point, and by tapering, the strength is gradually improved from the original diameter part to the tip diameter part in the longitudinal direction of the steel pipe, and the rigidity of the entire steel pipe And a method of manufacturing a tapered steel pipe characterized by improving
【０００６】本発明によれば、鋼管の元径部から先端径
部の間で徐々に強度を向上させると同時に伸びの低下も
伴わないために、鋼管先端の径の細い部分でも元径と同
等の剛性を持たせることができるので、二次加工も容易
にでき、かつ長尺なテーパー鋼管を製造することができ
る。従って、二次加工するような照明柱に対して、１体
型であるがゆえに連結部での応力集中もなく、照明塔と
して使われる場合において、横風等に耐えられる限界が
広がるという特徴を持つ。According to the present invention, the strength is gradually improved from the original diameter portion to the tip diameter portion of the steel pipe, and at the same time, the elongation is not reduced. , The secondary processing can be easily performed, and a long tapered steel pipe can be manufactured. Therefore, the lighting column which is subjected to the secondary processing is characterized in that since it is a one-piece type, there is no stress concentration at the connecting portion, and when used as a lighting tower, the limit to withstand crosswinds and the like is widened.
【０００７】[0007]
【発明の実施の形態】本発明においては、鋼管の種類と
しては既存の鋼管材を使用しており、その種類、サイ
ズ、製造方法等は従来と同様で一般的なものであり、特
にこだわるものではない。本発明でいうテーパー鋼管と
は、ロールを鋼管長手方向に垂直に押し当て、鋼管の元
径を長手方向に対してあるテーパー率により徐々に絞り
込み、径を細めて行くという両端の径が異なる鋼管のこ
とである（図１）。DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, existing steel pipe materials are used as the types of steel pipes. is not. The tapered steel pipe as referred to in the present invention is a steel pipe having different diameters at both ends, in which a roll is pressed perpendicularly to the longitudinal direction of the steel pipe, and the original diameter of the steel pipe is gradually reduced by a certain taper ratio with respect to the longitudinal direction, and the diameter is reduced. (FIG. 1).
【０００８】以下に、本発明について詳細に説明する。
本発明においては、鋼管全体を加熱しながらロールを押
し込むことによりテーパー加工することで、材料が鋼管
長手方向においてテーパー率の度合いにより徐々に加工
硬化して行き、鋼管長手方向における強度分布を変化さ
せ、伸びの低下を伴わないことが特徴である。その方法
は、鋼管全体を加熱しながら、鋼管の周方向にローラー
を押し当て、管長手方向に対して材料を流動させて行
き、材料の組織を歪ませて加工して行くことにより、加
工量に応じて加工硬化をさせて行くものであり、一般に
行われているスピニング加工等と同様で、鋼管全体を加
熱しながら加工すること以外は特にこだわるものではな
い。Hereinafter, the present invention will be described in detail.
In the present invention, the material is gradually worked and hardened by the degree of the taper ratio in the longitudinal direction of the steel pipe by tapering by pressing the roll while heating the entire steel pipe, and the strength distribution in the longitudinal direction of the steel pipe is changed. It is characterized by no accompanying decrease in elongation. The method is to press the roller in the circumferential direction of the steel pipe while heating the entire steel pipe, to flow the material in the longitudinal direction of the pipe, to deform the structure of the material, and to process the material. Work hardening is carried out in accordance with the above conditions, and is not particularly limited except for processing while heating the entire steel pipe as in the case of spinning or the like generally performed.
【０００９】本発明のように、テーパー加工をした鋼管
を、小型引張試験片を用いて、管長手方向に対して試験
片採取位置を変えて引張試験をした場合、その降伏強
度、引張強度は、テーパー加工による加工硬化度、加工
時の温度に支配される。その結果、鋼管の長手方向に対
しては、径が細くなるに従い強度が上昇する。これによ
り、鋼管全体の剛性を向上させるとともに、より長尺な
テーパー鋼管を得ることができる。また、加工による伸
びの低下が起こらないため、二次加工も容易にできる。As in the present invention, when a tapered steel pipe is subjected to a tensile test using a small tensile test specimen while changing the test specimen collection position in the longitudinal direction of the pipe, the yield strength and the tensile strength are as follows. , The degree of work hardening by taper processing, and the temperature during processing. As a result, in the longitudinal direction of the steel pipe, the strength increases as the diameter decreases. Thereby, the rigidity of the whole steel pipe can be improved, and a longer tapered steel pipe can be obtained. In addition, since the elongation does not decrease due to the processing, the secondary processing can be easily performed.
【００１０】以上のように、鋼管長手方向において元径
部から先端径部の間で徐々に強度を上昇させ、伸びの低
下を伴わないようにするためには、材料が加工硬化する
と同時に歪みの回復もするような条件を満足させなけれ
ばならない。その要因には、以下のようなものがある。 （１）加工温度の影響 （２）加工時のテーパー率の影響 （３）テーパー加工量（加工した絶対量） 以上のものに対する条件設定は、鋼管の材質により異な
る。As described above, in order to gradually increase the strength between the original diameter portion and the tip diameter portion in the longitudinal direction of the steel pipe so as not to decrease the elongation, the material is hardened at the same time as the work hardens. We have to satisfy the conditions that will allow us to recover. The factors are as follows. (1) Influence of processing temperature (2) Influence of taper rate during processing (3) Amount of taper processing (absolute amount processed) The condition setting for the above items differs depending on the material of the steel pipe.
【００１１】次に、本発明における鋼管製造条件の限定
理由について説明する。本発明は、鋼管の元径部から先
端径部の間で徐々に強度を上昇させることにより、鋼管
全体の剛性を向上させることを狙いとしたものである。
鋼管長手方向の強度上昇については、テーパー加工のテ
ーパー率により異なるが、冷間加工では加工率の上昇と
ともに伸びの低下が急激に起こるため、長尺のテーパー
鋼管を得ることができない。また、先端部分を曲げたり
する二次加工が困難である。これらを防ぐためには、加
工時の加熱温度を１００℃以上にする必要がある。ま
た、材料のＡｃ1 変態点を超えるような温度まで加熱し
て加工すると、ミクロ組織の変化や歪みの回復等が著し
く起こるため、強度の上昇が起こらない。ここで、Ａｃ
1 変態点とは鋼の共析変態点をいう。従って、材料の制
約などを考えると、加工時の加熱範囲は、１００℃以
上、Ａｃ1 変態点温度以下とする必要がある。例えば、
４０キロ級一般構造用鋼管の場合、５００〜６００℃に
加熱して加工を行う。Next, the reasons for limiting the steel pipe production conditions in the present invention will be described. The present invention aims at improving the rigidity of the entire steel pipe by gradually increasing the strength between the original diameter part and the tip diameter part of the steel pipe.
The increase in strength in the longitudinal direction of the steel pipe differs depending on the taper rate of the taper processing. However, in cold working, the elongation rapidly decreases with the increase in the processing rate, so that a long tapered steel pipe cannot be obtained. Also, it is difficult to perform secondary processing such as bending the tip portion. In order to prevent these, the heating temperature during processing needs to be 100 ° C. or higher. Further, when the material is heated to a temperature exceeding the Ac 1 transformation point and processed, the change in microstructure and the recovery of strain occur remarkably, so that the strength does not increase. Where Ac
1 Transformation point refers to the eutectoid transformation point of steel. Therefore, in consideration of material restrictions and the like, the heating range at the time of processing needs to be 100 ° C. or higher and the Ac 1 transformation point temperature or lower. For example,
In the case of a steel pipe for a 40-kg class general structure, processing is performed by heating to 500 to 600 ° C.
【００１２】テーパー加工量については、加工時の加熱
温度と相対的な関係があり、強度の向上を図り得る加工
条件に合わせて、１０〜８５％の間にて適宜選択すれば
よい。また、テーパー率については、現在一般的なテー
パー鋼管の場合１％であるが、強度の向上を図り得る加
工条件に合わせて、１〜２５％の間にて適宜選択すれば
よい。従って、テーパー鋼管の長さも自由に選択でき
る。The amount of taper processing has a relative relationship with the heating temperature at the time of processing, and may be appropriately selected from 10 to 85% in accordance with processing conditions that can improve strength. Further, the taper ratio is 1% in the case of a currently general tapered steel pipe, but may be appropriately selected from 1 to 25% in accordance with processing conditions that can improve the strength. Therefore, the length of the tapered steel pipe can be freely selected.
【００１３】[0013]
【実施例】表１にテーパー加工の実施例を示す。表中の
Ａ、Ｂが本発明の実施例であり、比較例としては、Ｃが
冷間加工法（常温）によるテーパー鋼管の強度分布であ
り、Ｄが現在製造されている板巻き法によるテーパー鋼
管の強度分布である。EXAMPLES Table 1 shows examples of the taper processing. In the table
A and B are examples of the present invention, and as a comparative example, C is the strength distribution of the tapered steel pipe by the cold working method (normal temperature), and D is the strength of the currently manufactured tapered steel pipe by the sheet winding method. Distribution.
【００１４】[0014]
【表１】 [Table 1]
【００１５】[0015]
【発明の効果】本発明により、高速道路の照明塔などに
使用されるテーパー鋼管の剛性を向上でき、かつ連結部
の減少を可能とするもので、産業上極めて大きな効果が
期待される。According to the present invention, the rigidity of a tapered steel pipe used for a lighting tower or the like on a highway can be improved, and the number of connecting portions can be reduced.
【図１】本発明に従って製造されたテーパー鋼管の説明
図である。FIG. 1 is an explanatory view of a tapered steel pipe manufactured according to the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 栗山 幸久 富津市新富20−１ 新日本製鐵株式会社 技術開発本部内 (72)発明者 秋吉 秀保 京都府亀岡市西つつじケ丘大山台１丁目 ３−５ (72)発明者 村田 重雄 兵庫県神戸市垂水区小束山１丁目３番28 −302 審査官 田中 則充 (56)参考文献 特開 平５−33012（ＪＰ，Ａ) 特開 平６−65643（ＪＰ，Ａ) 特開 昭48−84763（ＪＰ，Ａ) 特開 昭56−160829（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B21C 37/00 - 43/04 C21D 7/00 - 8/10 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Yukihisa Kuriyama 20-1 Shintomi, Futtsu-shi Nippon Steel Corporation Technology Development Division (72) Inventor Hideho Akiyoshi 1-5-3 Oyamadai, Nishi-Atsujigaoka, Kameoka-shi, Kyoto 72) Inventor Shigeo Murata 1-328-302 Kobashiyama, Tarumi-ku, Kobe-shi, Hyogo Examiner Norimitsu Tanaka (56) References JP-A-5-33012 (JP, A) JP-A-6-65643 (JP, A) JP-A-48-84763 (JP, A) JP-A-56-160829 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B21C 37/00-43/04 C21D 7 / 00-8/10
Claims (1)
変態点までの間の任意温度にて加熱しながらロールを押
し込み、テーパー加工することにより、鋼管長手方向に
対して元径部から先端径部の間で徐々に強度を向上さ
せ、鋼管全体の剛性を向上させることを特徴とするテー
パー鋼管の製造法。1. A steel pipe as a whole is heated from 100 ° C. to Ac 1 of the material.
The roll is pushed in while heating at an arbitrary temperature up to the transformation point, and by tapering, the strength is gradually improved from the original diameter part to the tip diameter part in the longitudinal direction of the steel pipe, and the rigidity of the entire steel pipe The manufacturing method of a taper steel pipe characterized by improving.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03920496A JP3328795B2 (en) | 1996-02-27 | 1996-02-27 | Manufacturing method of tapered steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03920496A JP3328795B2 (en) | 1996-02-27 | 1996-02-27 | Manufacturing method of tapered steel pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09225525A JPH09225525A (en) | 1997-09-02 |
| JP3328795B2 true JP3328795B2 (en) | 2002-09-30 |
Family
ID=12546610
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03920496A Expired - Lifetime JP3328795B2 (en) | 1996-02-27 | 1996-02-27 | Manufacturing method of tapered steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3328795B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5203432B2 (en) * | 2010-09-06 | 2013-06-05 | ヨシモトポール株式会社 | Antenna pole |
-
1996
- 1996-02-27 JP JP03920496A patent/JP3328795B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09225525A (en) | 1997-09-02 |
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