JPH06218431A - Method for straightening steel tube at worm state - Google Patents
Method for straightening steel tube at worm stateInfo
- Publication number
- JPH06218431A JPH06218431A JP963093A JP963093A JPH06218431A JP H06218431 A JPH06218431 A JP H06218431A JP 963093 A JP963093 A JP 963093A JP 963093 A JP963093 A JP 963093A JP H06218431 A JPH06218431 A JP H06218431A
- Authority
- JP
- Japan
- Prior art keywords
- steel tube
- straightener
- steel
- temperature
- steel pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- General Induction Heating (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、ロータリーストレート
ナーによる鋼管の曲がり矯正法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of straightening a steel pipe using a rotary straightener.
【0002】[0002]
【従来の技術】機械構造用鋼管の中には、切削性を確保
するため材料剛性のよい冷間加工のままの材料を要求さ
れるものがあり、この種の材料としては共析鋼または過
共析鋼が用いられることが多い。しかし、これらの鋼で
は炭素含有量が高いため、冷間加工のままでは高強度で
低靱性となり、冷間加工後の曲がり矯正時に脆性割れが
生じやすい。したがって、この曲がり矯正工程での割れ
防止対策が必要である。2. Description of the Related Art Some steel pipes for machine structures are required to be cold-worked with good material rigidity in order to ensure machinability. Eutectoid steel is often used. However, since these steels have a high carbon content, they have high strength and low toughness when they are cold-worked, and brittle cracks are likely to occur during bending straightening after cold-working. Therefore, it is necessary to take measures to prevent cracks in the bending correction process.
【0003】鋼管の曲がり矯正を行う際の割れ発生防止
対策としては、鋼管に外部から熱を加えた加温状態で、
あるいは鋼管が前の工程で加熱を受けた後まだ十分冷却
していない状態で矯正するのが効果的である。その方法
としては、 (1) 冷間引抜時の加工熱を利用する方法 (2) 熱処理直後の余熱を利用する方法 (3) 鋼管を加温液内に浸漬して加熱する方法 などがあげられる。As a measure for preventing the occurrence of cracks when straightening the bend of a steel pipe, the steel pipe is heated under external heating,
Alternatively, it is effective to correct the steel pipe after it has been heated in the previous step and has not yet been sufficiently cooled. The methods include (1) a method that utilizes the processing heat during cold drawing, (2) a method that utilizes the residual heat immediately after heat treatment, and (3) a method that involves heating the steel pipe by immersing it in a heating liquid. .
【0004】一方、矯正後はライン内で非破壊検査を実
施することが多く、鋼管が有する熱による検査用機器の
損傷や検査精度の低下を防止するため、矯正後に鋼管を
冷却する必要が生ずる。On the other hand, after straightening, a non-destructive inspection is often carried out in the line, and it is necessary to cool the steel pipe after straightening in order to prevent damage to the inspection equipment and deterioration of inspection accuracy due to the heat of the steel pipe. .
【0005】前記の (1)および(2) の方法では、鋼管全
体がかなり加温された状態にあるため、その後の冷却時
において冷却能力の大きい冷却装置が必要となるか、あ
るいはサイクルタイムが長くなる。In the above methods (1) and (2), since the entire steel pipe is in a considerably heated state, a cooling device having a large cooling capacity is required during the subsequent cooling, or the cycle time is shortened. become longer.
【0006】また、 (2)の方法は熱処理材を対象とする
場合にのみ用いることができる方法である。このような
理由で、(1) および(2) の方法はいずれも、矯正前の適
切な加温方法としては適用が困難なものである。The method (2) can be used only when a heat-treated material is used. For this reason, the methods (1) and (2) are both difficult to apply as appropriate heating methods before correction.
【0007】(3) の方法では、液温管理や浸漬時間管理
により、管の表面近傍のみを加熱することが可能である
ため、ストレートナー使用時の割れ防止対策として有効
である。また、鋼管の保有する熱が (1)や(2) の方法と
比較して小さいため矯正後の冷却も容易である。しか
し、液による鋼管の腐食が懸念され、防錆効果のある液
を使用するとしても乾燥は必要であり、特に小径の長尺
材に適用する場合にはこの乾燥の点からの問題が多い。In the method (3), it is possible to heat only the vicinity of the surface of the pipe by controlling the liquid temperature and the dipping time, which is effective as a crack prevention measure when using the straightener. In addition, the heat retained by the steel pipe is small compared to methods (1) and (2), so cooling after straightening is also easy. However, there is a concern that the steel pipe may be corroded by the liquid, and even if a liquid having an anticorrosive effect is used, it is necessary to dry it. Especially, when it is applied to a long-diameter material having a small diameter, there are many problems from this drying point.
【0008】特開昭58−116932号公報には、大径鋼管を
スパイラル状に搬送しながら、誘導加熱炉に通して特定
温度に加熱昇温した後、ローラーにより矯正を行う鋼管
の矯正方法および装置が示されているが、これは Ac1点
以下の加熱を施す残留応力除去焼鈍と真円度を高めるた
めのものである。Japanese Unexamined Patent Publication (Kokai) No. 58-116932 discloses a method for straightening a steel pipe in which a large-diameter steel pipe is conveyed in a spiral shape, heated in a induction heating furnace to a specific temperature, and then straightened by rollers. An apparatus is shown, which is for increasing the roundness and residual stress relief annealing by heating below the Ac 1 point.
【0009】特開昭58−202915号公報には、冷間引抜加
工後の管棒材を連続的に順次曲がり矯正する際に、この
矯正を材料の脆性遷移温度以上で行って、焼鈍と再潤滑
処理を省略する管棒材の製造方法が示されている。しか
し、この方法では、引抜加工完了から曲がり矯正の間を
ライン化しても、放冷中に材料温度低下が起こるため、
必ずしも脆性遷移温度以上で曲がり矯正ができるとは限
らない。しかも、引抜加工と曲がり矯正機をライン化す
る必要があり、設備費が高くつく。また、引抜加工後の
曲がり量が大きくなった被処理材を矯正機に装入できな
い場合、材料温度が高いため、ハンド処理性に劣るなど
の問題がある。In Japanese Patent Laid-Open No. 58-202915, when straight and straight bending of a tube rod material after cold drawing is performed, this straightening is performed at a brittle transition temperature of the material or above, and annealing and re-annealing are performed. A method of manufacturing a tube rod material which omits a lubrication process is shown. However, in this method, even if a line is drawn between the completion of the drawing process and the straightening of the bend, the material temperature will drop during cooling,
It is not always possible to straighten a bend above the brittle transition temperature. Moreover, it is necessary to line up the drawing process and the bending straightening machine, and the equipment cost is high. In addition, when the material to be processed having a large amount of bending after the drawing process cannot be loaded into the straightening machine, there is a problem that the material temperature is high and thus the hand processing property is poor.
【0010】特開平4−111926号公報には、鋼管の内部
に管端から温風を送り、内表面近傍を 400℃以下に加温
することを特徴とするロータリーストレートナーによる
鋼管の温間矯正法が示されている。しかし、鋼管を 400
℃近くまで加温することは、冷間加工のままで用いるべ
き材料の場合では熱処理することと同等となるから、青
熱脆性の危険性があるような材料にはこの方法は適用で
きない。さらに、この方法では、温風発生装置と環境対
策のための吸引装置が必要となる。In Japanese Patent Laid-Open No. 4-111926, warm air is sent to the inside of a steel pipe from the pipe end to heat the vicinity of the inner surface to 400 ° C. or below, thereby warming the steel pipe with a straightener. The law is shown. However, the steel pipe
Since heating up to near ℃ is equivalent to heat treatment in the case of a material that should be used as it is in cold working, this method cannot be applied to a material that has a risk of blue-heat embrittlement. Furthermore, this method requires a warm air generator and a suction device for environmental protection.
【0011】[0011]
【発明が解決しようとする課題】本発明の目的は、共析
鋼または過共析鋼から製造される冷間加工後の鋼管を対
象とする、簡便で、かつ割れ防止に効果的な温間矯正法
を提供することにある。DISCLOSURE OF THE INVENTION An object of the present invention is to provide a simple, warm-working warm pipe for cold-worked steel pipe produced from eutectoid or hypereutectoid steel. To provide a correction method.
【0012】[0012]
【課題を解決するための手段】本発明の要旨は、次の方
法にある。The gist of the present invention lies in the following method.
【0013】ロータリーストレートナーを用いて、C含
有量が 0.4%以上の共析鋼または過共析鋼の鋼管を温間
矯正する際に、誘導加熱装置を用いて、ロータリースト
レートナー入口における鋼管の加温温度を70℃以上、 2
00℃以下にすることを特徴とする鋼管の温間矯正法。When a steel pipe of eutectoid or hypereutectoid steel having a C content of 0.4% or more is warm-corrected by using a rotary straightener, an induction heating device is used to remove the steel pipe at the inlet of the rotary straightener. Heating temperature 70 ℃ or more, 2
A warm straightening method for steel pipes, which is characterized by keeping the temperature below 00 ° C.
【0014】本発明者は、冷間加工のままので用いるべ
き材料を対象としていること、および上記鋼は低脆性材
であると言えども、その延性脆性遷移温度が高々 100℃
前後であることから、大がかりな設備設置が不要な誘導
加熱装置に注目して、適切な割れ防止の解決方法を検討
した。The inventor of the present invention is intended for a material to be used as it is as cold-worked, and although the above steel is a low brittle material, its ductile brittle transition temperature is 100 ° C. at most.
Since it is before and after, we focused on induction heating devices that do not require large-scale equipment installation, and examined appropriate crack prevention solutions.
【0015】図1は、本発明の方法を実施するための装
置の構成を示す概略の平面図である。図中、1は装入用
テーブル、2は鋼管(冷間加工のまま)、3は入口トラ
フ、4は誘導加熱装置、5はロータリーストレートナー
方式の矯正機本体、6は冷却用テーブルである。FIG. 1 is a schematic plan view showing the structure of an apparatus for carrying out the method of the present invention. In the drawing, 1 is a charging table, 2 is a steel pipe (as cold working), 3 is an inlet trough, 4 is an induction heating device, 5 is a rotary straightener type straightener main body, and 6 is a cooling table. .
【0016】[0016]
【作用】図1に示すように、冷間加工後の鋼管2は、装
入用テーブル1から入口トラフ3を経て誘導加熱装置4
に送られ、ここで前記の定められた温度に加温され、ロ
ータリーストレートナー方式の矯正機本体5で曲がり矯
正を行う。その後、冷却用テーブル6で空冷され、非破
壊検査を受ける。As shown in FIG. 1, the cold-worked steel pipe 2 is heated by the induction heating device 4 from the charging table 1 through the inlet trough 3.
And is then heated to the above-mentioned predetermined temperature, and the bending straightening is performed by the rotary straightener type straightening machine main body 5. Then, it is air-cooled on the cooling table 6 and undergoes a nondestructive inspection.
【0017】本発明の方法において誘導加熱装置4を用
いるのは次の〜の理由による。The induction heating device 4 is used in the method of the present invention for the following reasons.
【0018】急速加熱が可能であり、精整設備の能率
を阻害することなく加温することができる。Rapid heating is possible, and heating can be performed without impairing the efficiency of the conditioning equipment.
【0019】電流制御などによる加温温度のバラツキ
が少ない。There is little variation in heating temperature due to current control or the like.
【0020】オンライン処理とすることができ、かつ
コイル替えなどの段取替えがない。On-line processing is possible, and there is no setup change such as coil change.
【0021】C含有量が 0.4%の以上の共析鋼または過
共析鋼の材料加温温度を 200℃以下としたのは、この温
度を超えると事実上熱処理することと同じになり、加温
後の材料強度および金属組織を冷間加工のままと同じ状
態に保つことができないからである。また、誘導加熱装
置の設備費増大および設備スペース増大を防ぐためであ
る。The reason why the material heating temperature of the eutectoid or hyper-eutectoid steel having a C content of 0.4% or more is set to 200 ° C. or less is the same as the fact that heat treatment is practically performed when this temperature is exceeded. This is because the material strength after warming and the metal structure cannot be maintained in the same state as they were during cold working. Further, this is to prevent an increase in equipment cost and an increase in equipment space of the induction heating device.
【0022】加温下限温度を70℃としたのは、上記の共
析鋼または過共析鋼における衝撃破壊遷移温度が70℃で
あり、70℃未満では常温加工と同様の条件となるため、
ストレートナー矯正による割れが発生しやすいからであ
る。The lower limit of heating temperature is set to 70 ° C. because the impact fracture transition temperature in the above eutectoid or hypereutectoid steel is 70 ° C.
This is because cracking is likely to occur due to straightener straightening.
【0023】[0023]
【実施例】表1に示すJIS G 4805に規定されたSUJ 2 に
相当する化学組成の鋼管を、冷間引抜き(引抜減面率36
%)で製造し、直径35.85mm 、肉厚3.85mm、長さ 25000
mmの管とした。これらの鋼管に表2に示す条件で温間矯
正を施した。[Example] A steel pipe having a chemical composition corresponding to SUJ 2 specified in JIS G 4805 shown in Table 1 was cold drawn (drawing reduction ratio 36
%), Diameter 35.85mm, wall thickness 3.85mm, length 25000
mm tube. These steel pipes were warm-corrected under the conditions shown in Table 2.
【0024】誘導加熱装置は、出力周波数 500Hz 、出
力電力260kW、インバーター出力200kW、コイル内径 1
00mm、コイル長さ400mm のものを用いた。The induction heating device has an output frequency of 500 Hz, an output power of 260 kW, an inverter output of 200 kW, and a coil inner diameter of 1
A coil with a length of 00 mm and a coil length of 400 mm was used.
【0025】曲がり矯正機は、対向式(2−2−2−
1)のロータリーストレートナーを用いた。ストレート
ナーのクラッシュ段取は、 No.1ロールおよび No.3ロ
ールについては、それぞれ一定( No.1クラッシュ:0
mm、 No.3クラッシュ: 1.6mm)とし、 No.2ロールに
ついては、表2に示すように、そのクラッシュを 1.9mm
(通常段取)および 2.5mmの2条件とした。オフセット
は No.2ロールで16.0mm、被処理材の送り速度は30m/mi
n の一定条件とした。材料温度は接触式温度計を使用し
て測定した。The bending straightening machine is of the opposed type (2-2-2
The rotary straightener of 1) was used. Straightener crash setup is constant for No. 1 roll and No. 3 roll (No. 1 crash: 0
mm, No. 3 crush: 1.6 mm), and No. 2 roll has a crush of 1.9 mm as shown in Table 2.
(Normal setup) and 2.5mm. The No. 2 roll has an offset of 16.0 mm, and the feed speed of the processed material is 30 m / mi.
A constant condition of n was set. The material temperature was measured using a contact thermometer.
【0026】このようにして得られた鋼管について、渦
流探傷と超音波探傷により、鋼管内外面割れ有無および
矯正前後の鋼管の硬度を調査した。硬度測定用のサンプ
ルは管後端から切り出したものを用い、HRBで横断面
肉厚中心部4点法により測定した。これらの結果を表2
に併せて示す。With respect to the steel pipe thus obtained, the presence or absence of cracks on the inner and outer surfaces of the steel pipe and the hardness of the steel pipe before and after correction were examined by eddy current flaw detection and ultrasonic flaw detection. A sample cut from the rear end of the tube was used as a sample for hardness measurement, and the hardness was measured by a four-point method at the center of the cross-section wall thickness by HRB. These results are shown in Table 2.
Are also shown.
【0027】表2から明らかなように、本発明例では、
加温条件が本発明で定める範囲外の比較例と対比して、
割れ発生がないか、あるいは割れ発生率が低い。As is apparent from Table 2, in the example of the present invention,
In contrast to the comparative example in which the heating conditions are outside the range defined by the present invention,
No cracking or low cracking rate.
【0028】[0028]
【表1】 [Table 1]
【0029】[0029]
【表2】 [Table 2]
【0030】[0030]
【発明の効果】本発明の方法によれば、C含有量が 0.4
%の以上の共析鋼または過共析鋼の鋼管を冷間加工した
後、ロータリーストレートナーにより曲がりを矯正する
際に、鋼管の割れ発生を防止しつつ、効果的な曲がり矯
正を行うことができる。According to the method of the present invention, the C content is 0.4
% Of the eutectoid or hyper-eutectoid steel is cold-worked, and when straightening the bend with a rotary straightener, it is possible to prevent the occurrence of cracks in the pipe and perform effective straightening. it can.
【図1】本発明の方法を実施するための装置の構成を示
す概略の平面図である。FIG. 1 is a schematic plan view showing the structure of an apparatus for carrying out the method of the present invention.
1:装入用テーブル、2:鋼管、3:入口トラフ、4:
誘導加熱装置、5:ロータリーストレートナー方式の矯
正機本体、6:冷却用テーブル1: Charging table, 2: Steel pipe, 3: Entrance trough, 4:
Induction heating device, 5: Rotary straightener type straightener main body, 6: Cooling table
Claims (1)
有量が 0.4%以上の共析鋼または過共析鋼の冷間加工後
の鋼管を温間矯正する際に、誘導加熱装置を用いて、ロ
ータリーストレートナー入口における鋼管の加温温度を
70℃以上、 200℃以下にすることを特徴とする鋼管の温
間矯正法。1. When using a rotary straightener to warm-correct a cold-worked steel tube of eutectoid or hypereutectoid steel having a C content of 0.4% or more, an induction heating device is used. The heating temperature of the steel pipe at the inlet of the rotary straightener
A warm straightening method for steel pipes characterized in that the temperature is 70 ° C or higher and 200 ° C or lower.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP963093A JPH06218431A (en) | 1993-01-25 | 1993-01-25 | Method for straightening steel tube at worm state |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP963093A JPH06218431A (en) | 1993-01-25 | 1993-01-25 | Method for straightening steel tube at worm state |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH06218431A true JPH06218431A (en) | 1994-08-09 |
Family
ID=11725570
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP963093A Pending JPH06218431A (en) | 1993-01-25 | 1993-01-25 | Method for straightening steel tube at worm state |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH06218431A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012128258A1 (en) * | 2011-03-24 | 2012-09-27 | 住友金属工業株式会社 | Austenite system alloy pipe and manufacturing method thereof |
-
1993
- 1993-01-25 JP JP963093A patent/JPH06218431A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012128258A1 (en) * | 2011-03-24 | 2012-09-27 | 住友金属工業株式会社 | Austenite system alloy pipe and manufacturing method thereof |
JP5137048B2 (en) * | 2011-03-24 | 2013-02-06 | 新日鐵住金株式会社 | Austenitic alloy pipe and manufacturing method thereof |
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