JP3214348B2 - Manufacturing method of alloy steel pipe - Google Patents
Manufacturing method of alloy steel pipeInfo
- Publication number
- JP3214348B2 JP3214348B2 JP09601896A JP9601896A JP3214348B2 JP 3214348 B2 JP3214348 B2 JP 3214348B2 JP 09601896 A JP09601896 A JP 09601896A JP 9601896 A JP9601896 A JP 9601896A JP 3214348 B2 JP3214348 B2 JP 3214348B2
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- Prior art keywords
- temperature
- steel pipe
- strength
- steel
- constant temperature
- Prior art date
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- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、Ｃｒ−Ｍｏ鋼を
基本成分とするボイラー用鋼材を、熱間加工と熱処理を
組合せることによって、従来の調質鋼と同等の強度およ
び延性を有する鋼管とする合金鋼鋼管の製造方法に関す
る。BACKGROUND OF THE INVENTION The present invention relates to a steel pipe having the same strength and ductility as a conventional tempered steel by combining hot working and heat treatment with a boiler steel material containing a Cr-Mo steel as a basic component. And a method for producing an alloy steel pipe.
【０００２】[0002]
【従来の技術】火力発電用のボイラには、水壁管、過熱
器管、再熱器管、節炭器管、給水加熱器管、主蒸気管な
どとして多種類の耐熱鋼管が使用されているが、いずれ
も高温強度や耐酸化性、耐腐食性といった性能が要求さ
れる。これらの性能を満足させるためには、Ｃｒで耐熱
性を確保し、Ｍｏ、Ｎ、Ｎｂによる固溶強化と各元素の
炭化物による分散強化を利用して性能確保を図ってい
る。2. Description of the Related Art Many types of heat-resistant steel pipes are used in boilers for thermal power generation, such as water wall pipes, superheater pipes, reheater pipes, economizer pipes, feed water heater pipes, and main steam pipes. However, all of them require high-temperature strength, oxidation resistance, and corrosion resistance. In order to satisfy these performances, the heat resistance is secured by Cr, and the performance is secured by utilizing solid solution strengthening by Mo, N, and Nb and dispersion strengthening by carbide of each element.
【０００３】従来の耐熱鋼管の製造方法としては、熱間
または冷間加工で所定の形状に仕上げたのち、調質熱処
理を施して強度とミクロ組織の調整を行っている。調質
熱処理方法としては、前記Ｃｒ、Ｍｏ、Ｎ、Ｎｂなどを
添加したボイラ鋼管についてはＡｃ3点以上に加熱して
オーステナイト化した後、Ａｅ1点以下のある温度に冷
却し、その温度に保持したままで変態させる恒温変態処
理が適用されている。一般的に、恒温変態処理後の室温
強度は、耐力２５０〜３５０Ｎ／ｍｍ2、引張強さ４５
０〜５５０Ｎ／ｍｍ2であることが要求される。[0003] As a conventional method for manufacturing a heat-resistant steel pipe, after finishing to a predetermined shape by hot or cold working, heat treatment is performed to adjust strength and microstructure. As the heat treatment heat treatment method, the boiler steel pipe to which Cr, Mo, N, Nb, etc. are added is heated to an austenite by heating it to more than three points, and then cooled to a certain temperature not more than one point of Ae. A constant temperature transformation process for transforming while holding is applied. Generally, the room temperature strength after the isothermal transformation treatment is as follows: yield strength 250-350 N / mm 2 , tensile strength 45
It is required to be 0 to 550 N / mm 2 .
【０００４】上記ボイラ用鋼管の製造においては、鋼管
の仕上げ加工タイミングと調質熱処理タイミングが合わ
ないことが多く、待ち時間が長くなること、調質熱処理
の際に室温からの加熱が必要で、加熱後の恒温変態処理
と相まって処理時間が長く低能率であること、高温での
長時間加熱となるためスケールの生成量が著しく多く、
調質熱処理後に酸洗やグラインダー等によるデスケール
処理が必要になるといった問題点を有している。特に、
調質熱処理でのスケール生成は、冷間仕上加工材につい
ては雰囲気ガスを制御した焼鈍炉で調質熱処理すること
により解決できるが、熱間仕上加工材は、熱間仕上で生
成したスケールが存在するため、雰囲気ガスを制御した
焼鈍炉で調質熱処理しても、表面組織の改善までには至
らないといった問題を有している。In the production of the above-mentioned steel pipe for a boiler, the finish processing timing of the steel pipe often does not coincide with the heat treatment heat treatment timing, so that the waiting time becomes longer, and heating from room temperature is required during the heat treatment heat treatment. The treatment time is long and low efficiency combined with the isothermal transformation treatment after heating, and the amount of scale generation is remarkably large due to long-time heating at high temperature.
There is a problem that after the refining heat treatment, a descaling treatment by pickling or a grinder is required. In particular,
The scale formation in the temper heat treatment can be solved by performing the temper heat treatment in an annealing furnace with controlled atmosphere gas for the cold-finished work material, but there is scale generated in the hot finish work material. Therefore, there is a problem that even if the refining heat treatment is performed in an annealing furnace with controlled atmosphere gas, the surface structure is not improved.
【０００５】上記オフライン調質熱処理を省略して強度
とミクロ組織の調整を行う方法としては、Ｃ：０．０８
〜０．１３％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：
１．１０〜１．５０％、Ｎｉ：０．７０％以下および／
またはＣｕ：０．４５％以下、ならびにＣｒ：０．２０
％以下、Ｍｏ：０．０５％以下、Ｖ：０．０２％以下お
よびＢ：０．０００５％以下からなる群から選んだ少な
くとも１種、Ａｌ：０．００５〜０．０８０％、Ｎｂ：
０．００５〜０．０５０％、Ｎ：０．００１０〜０．０
０９０％、Ｔｉ：０．００５〜０．０３５％、残部Ｆｅ
および不可避的不純物からなる鋼組成を有する鋼片を１
０００℃以上の温度に加熱後、熱間加工を行って、さら
に、８８０〜９５０℃の温度で焼準を行う方法（特開平
２−３０５９１９号公報）が提案されている。As a method of adjusting the strength and the microstructure by omitting the off-line tempering heat treatment, C: 0.08
0.13%, Si: 0.05 to 0.50%, Mn:
1.10 to 1.50%, Ni: 0.70% or less and / or
Or, Cu: 0.45% or less, and Cr: 0.20
% Or less, Mo: 0.05% or less, V: 0.02% or less, and B: at least one selected from the group consisting of 0.0005% or less, Al: 0.005 to 0.080%, Nb:
0.005 to 0.050%, N: 0.0010 to 0.0
090%, Ti: 0.005 to 0.035%, balance Fe
And a slab having a steel composition consisting of unavoidable impurities
A method has been proposed in which after heating to a temperature of 000 ° C. or higher, hot working is performed, and normalizing is performed at a temperature of 880 to 950 ° C. (Japanese Patent Laid-Open No. 2-305919).
【０００６】[0006]
【発明が解決しようとする課題】上記特開平２−３０５
９１９号公報に開示の方法は、寒冷地において使用され
る溶接構造用鋼材またはラインパイプ用鋼管等として使
用される、低炭素当量で、優れた溶接性を具備し、かつ
低温衝撃特性に優れた焼準型高靭性高強度鋼材を得るも
のであって、高温強度や耐酸化性、耐腐食性が要求され
るボイラ用鋼材ではない。Problems to be Solved by the Invention
The method disclosed in Japanese Patent Application Publication No. 919 discloses a low carbon equivalent, excellent weldability, and excellent low-temperature impact properties, which are used as a steel material for a welding structure or a steel pipe for a line pipe used in a cold region. It is intended to obtain a normalized high-toughness high-strength steel material and is not a steel material for boilers requiring high-temperature strength, oxidation resistance and corrosion resistance.
【０００７】この発明の目的は、前記従来のオフライン
処理していた恒温変態処理を、熱間加工直後の加熱冷却
によりインラインで完結させる合金鋼鋼管の製造方法を
提供することにある。An object of the present invention is to provide a method of manufacturing an alloy steel pipe in which the above-mentioned conventional off-line constant temperature transformation treatment is completed in-line by heating and cooling immediately after hot working.
【０００８】[0008]
【課題を解決するための手段】この発明の請求項１の合
金鋼鋼管の製造方法は、Ｃ：０．０５〜０．３５％、Ｓ
ｉ：０．０２〜０．６０％、Ｍｎ：０．３〜１．８％、
Ｃｒ：０．２〜１０．０％、Ｍｏ：０．２〜１．５％を
含有し、残部がＦｅと不可避的不純物からなる組成を有
する鋼片を、１０５０〜１２８０℃の温度範囲に加熱
し、ピアサー、マンドレルおよびサイザーを用いて穿孔
と７５０℃以上の仕上げ温度で熱間圧延を行ったのち、
８００〜１０５０℃の温度範囲に再加熱して恒温温度ま
で５℃／秒以下の冷却速度で冷却し、６５０〜７８０℃
の温度範囲で０．２５〜２．０時間恒温変態処理したの
ち空冷することとしている。このように、上記組成を有
する鋼片を、熱間圧延加工したのち、直ちにインライン
で恒温変態処理することによって、オフライン熱処理を
省略してオフラインで恒温変態処理した鋼管と同等の強
度、延性を確保できると共に、表面性状を改善すること
ができる。According to a first aspect of the present invention, there is provided a method for manufacturing an alloy steel pipe, wherein C: 0.05 to 0.35%, S:
i: 0.02 to 0.60%, Mn: 0.3 to 1.8%,
A steel slab containing Cr: 0.2 to 10.0% and Mo: 0.2 to 1.5%, the balance being Fe and unavoidable impurities, is heated to a temperature range of 1050 to 1280 ° C. Then, after performing piercing and hot rolling at a finishing temperature of 750 ° C. or more using a piercer, a mandrel, and a sizer,
Reheat to a temperature range of 800 to 1050 ° C and cool to a constant temperature at a cooling rate of 5 ° C / sec or less, and 650 to 780 ° C
After performing a constant temperature transformation treatment in the temperature range of 0.25 to 2.0 hours, air cooling is performed. In this way, the steel slab having the above composition is hot-rolled and immediately subjected to in-line isothermal transformation, thereby omitting offline heat treatment and securing the same strength and ductility as steel pipes subjected to off-line isothermal transformation. And at the same time, the surface properties can be improved.
【０００９】また、この発明の請求項２の合金鋼鋼管の
製造方法は、Ｃ：０．０５〜０．３５％、Ｓｉ：０．０
２〜０．６０％、Ｍｎ：０．３〜１．８％、Ｃｒ：０．
２〜１０．０％、Ｍｏ：０．２〜１．５％を含み、さら
に、Ｖ：０．０１〜０．１５％、Ｎｂ：０．０１〜０．
１０％、Ｔｉ：０．０１〜０．１０％のうちの１種また
は２種以上を含有し、残部がＦｅと不可避的不純物から
なる組成を有する鋼片を、１０５０〜１２８０℃の温度
範囲に加熱し、ピアサー、マンドレルおよびサイザーを
用いて穿孔と７５０℃以上の仕上げ温度での熱間圧延を
行ったのち、８００〜１０５０℃の温度範囲に再加熱し
て恒温温度まで５℃／秒以下の冷却速度で冷却し、６５
０〜７８０℃の温度範囲で０．２５〜２．０時間恒温処
理したのち空冷することとしている。このように、上記
組成を有する鋼片を、熱間圧延加工したのち、直ちにイ
ンラインで恒温変態処理することによって、オフライン
熱処理を省略してオフラインで恒温変態処理した鋼管と
同等の強度、延性を確保できると共に、表面性状を改善
することができる。The method of manufacturing an alloy steel pipe according to claim 2 of the present invention is characterized in that: C: 0.05 to 0.35%, Si: 0.0
2-0.60%, Mn: 0.3-1.8%, Cr: 0.
2-10.0%, Mo: 0.2-1.5%, V: 0.01-0.15%, Nb: 0.01-0.
10%, Ti: A steel slab containing one or more of 0.01 to 0.10% and having a balance of Fe and inevitable impurities in a temperature range of 1050 to 1280 ° C. After heating, piercing using a piercer, a mandrel and a sizer and performing hot rolling at a finishing temperature of 750 ° C. or more, reheating to a temperature range of 800 to 1050 ° C. to a constant temperature of 5 ° C./sec or less. Cool at cooling rate, 65
Air-cooling is performed after a constant temperature treatment in a temperature range of 0 to 780 ° C. for 0.25 to 2.0 hours. In this way, the steel slab having the above composition is hot-rolled and immediately subjected to in-line isothermal transformation, thereby omitting offline heat treatment and securing the same strength and ductility as steel pipes subjected to off-line isothermal transformation. And at the same time, the surface properties can be improved.
【００１０】[0010]
【発明の実施の形態】この発明において、鋼片の化学組
成、熱間圧延条件ならびに調質熱処理条件を限定した理
由を説明する。BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the chemical composition, hot rolling conditions and temper heat treatment conditions of a steel slab in the present invention will be described.
【００１１】Ｃは鋼材の強度を向上させる作用を有する
元素であるが、０．０５％未満では引張強さ４５０Ｎ／
ｍｍ２以上の強度を確保することができず、また、０．
３５％を超えると引張強さが上昇し過ぎるので、０．０
５〜０．３５％とした。C is an element having an effect of improving the strength of the steel material, but if it is less than 0.05%, the tensile strength is 450 N / N.
mm2 or more cannot be secured.
If it exceeds 35%, the tensile strength will increase too much.
5 to 0.35%.
【００１２】Ｓｉは脱酸作用の他に、鋼材の強度を向上
させる作用を有する元素であるが、０．０２％未満では
その効果が十分でなく、また、０．６０％を超えると微
細均一に分散していた炭化物が粗大化するようになっ
て、強度の向上効果が見られなくなるので、０．０２〜
０．６０％とした。[0012] Si is an element having an effect of improving the strength of the steel material in addition to the deoxidizing effect. If the content is less than 0.02%, the effect is not sufficient. Since the carbides dispersed to become coarse and the effect of improving the strength cannot be seen,
0.60%.
【００１３】ＭｎはＣと同様鋼材の強度を向上させる作
用を有する元素であるが、０．３％未満ではその効果が
不十分で所望の強度をえることができず、また、１．８
％を超えると、降伏点が低減されないので、０．３〜
１．８％とした。Mn is an element having the effect of improving the strength of a steel material like C, but if it is less than 0.3%, its effect is insufficient and a desired strength cannot be obtained.
%, The yield point is not reduced.
1.8%.
【００１４】Ｃｒは鋼材の耐酸化性および強度を向上さ
せる作用を有する元素であるが、０．２％未満ではその
効果が十分でなく、また、１０．０％を超えると恒温変
態処理によるミクロ組織および降伏点と引張強さとのバ
ランス調整の向上効果が少なくなるので、０．２〜１
０．０％とした。[0014] Cr is an element having an effect of improving the oxidation resistance and strength of steel, but if its content is less than 0.2%, its effect is not sufficient. Since the effect of improving the balance between the structure and the yield point and the tensile strength is reduced, 0.2 to 1
0.0%.
【００１５】Ｍｏは鋼材の高温強度を向上させる作用を
有する元素であるが、０．２％未満ではその効果が十分
でなく、また、１．５％を超えると鋼材の高温強度が向
上するものの、延性が低下するようになるので、０．２
〜１．５％とした。Mo is an element having an effect of improving the high-temperature strength of a steel material. When the content is less than 0.2%, the effect is not sufficient. When the content exceeds 1.5%, the high-temperature strength of the steel material is improved. , Since the ductility decreases.
To 1.5%.
【００１６】Ｖ、Ｎｂ、Ｔｉは共に強度を向上させる元
素であり、その中でＶは、鋼材の高温強度を向上させる
作用を有する元素であるが、０．０１％未満ではその効
果が十分でなく、また、０．１５％を超えると鋼材の高
温強度が向上するものの、延性が低下するようになるの
で、０．０１〜０．１５％とした。V, Nb, and Ti are all elements that improve the strength. Among them, V is an element that has the effect of improving the high-temperature strength of the steel material. When the content exceeds 0.15%, the high-temperature strength of the steel material is improved, but the ductility is reduced. Therefore, the content is set to 0.01 to 0.15%.
【００１７】Ｎｂはサイザー圧延後の鋼材のオーステナ
イト粒径を微細化して強度、靭性および延性を向上させ
る作用を有する元素で、必要に応じて添加されるが、
０．０１％未満ではその効果が十分でなく、また、０．
１０％を超えるとその作用が飽和するので、０．０１〜
０．１０％とした。Nb is an element having a function of improving the strength, toughness and ductility by reducing the austenite grain size of the steel material after the sizer rolling, and is added as necessary.
If the content is less than 0.01%, the effect is not sufficient.
If the content exceeds 10%, the effect is saturated, so that 0.01 to
0.10%.
【００１８】ＴｉはＮｂと同様サイザー圧延後の鋼材の
オーステナイト粒径を微細化して強度、靭性および延性
を向上させる作用を有する元素で、必要に応じて添加さ
れるが、０．０１％未満ではその効果が十分でなく、ま
た、０．１０％を超えると延性が低下するようになるの
で、０．０１〜０．１０％とした。Ti is an element having a function of improving the strength, toughness and ductility by refining the austenite grain size of the steel material after the sizer rolling similarly to Nb, and is added as necessary. If the effect is not sufficient, and if it exceeds 0.10%, the ductility decreases, so the content was set to 0.01 to 0.10%.
【００１９】不可避的不純物としてＮ、ＰおよびＳの含
有は避けられないが、Ｎは鋼塊の割れ防止のために０．
０６％以下とするのが望ましく、また、Ｐは偏析バンド
の防止および靭性向上の観点から０．０２５％以下、望
ましくは０．０１５％以下とするのがよく、さらに、Ｓ
は圧延方向の靭性向上の観点から０．０１％以下、望ま
しくは０．００５％以下とするのがよい。Although inevitable inclusion of N, P and S as inevitable impurities, N is set at 0.1% to prevent cracking of the steel ingot.
P is preferably at most 0.025%, more preferably at most 0.015%, from the viewpoint of preventing segregation bands and improving toughness.
Is preferably 0.01% or less, and more preferably 0.005% or less from the viewpoint of improving the toughness in the rolling direction.
【００２０】鋼片の加熱は、鋼片を中心部まで均一に加
熱し、ミクロ組織の偏析などを除去した状態で、次工程
の穿孔および圧延を行うために施されるものであり、そ
の温度が１０５０℃未満でも結晶粒の微細化による靭性
向上には有効であるが、変形抵抗が著しく上昇し、熱間
加工に支障を来たし、また、１２８０℃を超えると、穿
孔時の加工発熱によってゼロ延性域に到達するようにな
るので、加熱温度を１０５０〜１２８０℃とした。The heating of the slab is carried out in order to uniformly heat the slab to the center and to perform drilling and rolling in the next step in a state where segregation of the microstructure is removed. If the temperature is lower than 1050 ° C., it is effective in improving the toughness by refining the crystal grains, but the deformation resistance is remarkably increased, which hinders the hot working. The heating temperature was set to 1050 to 1280 ° C. because the temperature reached the ductile range.
【００２１】加熱された鋼片は、ピアサーで穿孔され、
次いでマンドレルミルおよびサイザーで熱間圧延される
が、熱間圧延における仕上温度が７５０℃未満ではフェ
ライトが生成するようになって所望の恒温変態処理がで
きなくなる。また、仕上温度に上限値はないが、１１０
０℃を超えると極端な粗粒となることから、８５０〜１
０５０℃とするのが望ましい。さらに、マンドレルミル
およびサイザーでの圧延率は、小さくても結晶粒は微細
になるが、鋼管としての表面肌を考慮すれば、断面減少
率で３０％以上とするのが望ましい。The heated billet is pierced by a piercer,
Next, hot rolling is performed by a mandrel mill and a sizer. When the finishing temperature in hot rolling is lower than 750 ° C., ferrite is generated, and a desired isothermal transformation cannot be performed. Although there is no upper limit for the finishing temperature,
If the temperature exceeds 0 ° C., extremely coarse particles are formed.
It is desirably 050 ° C. Further, although the rolling ratio in the mandrel mill and the sizer is small, the crystal grains are fine even if they are small.
【００２２】熱間圧延後の再加熱は、オーステナイト化
するために行うものであり、８００℃未満では熱間圧延
後に生成したフェライトをオーステナイト化できず、ま
た、１０５０℃を超えるとオーステナイト粒径が粗大化
すると共に、炭化物を固溶してしまい、所望の強度が得
られないので、再加熱温度を８００〜１０５０℃とし
た。また、再加熱時間に制限はないが、オーステナイト
化は短時間で終了するので、いたずらに再加熱時間を長
くすると、エネルギー原単位の悪化によるコスト増を招
くこととなるので、３０分以下とするのが望ましい。Reheating after hot rolling is performed to austenite. Ferrite formed after hot rolling cannot be austenitized at a temperature lower than 800 ° C., and austenite grain size at a temperature higher than 1050 ° C. The reheating temperature was set to 800 to 1050 ° C., because the coarsening and the solid solution of the carbide did not provide the desired strength. Although there is no limitation on the reheating time, austenitization is completed in a short time, so if the reheating time is lengthened unnecessarily, the cost increases due to the deterioration of the energy consumption unit. It is desirable.
【００２３】鋼管の冷却に際しては、必ず肉厚方向に温
度分布が生じ、表面ほど冷却速度が大きくなる。冷却速
度は、大きくなるとベイナイトが生成し、本来の恒温変
態処理ができなくなるばかりでなく、最も冷却されない
部分との速度差が大きくなり、肉厚方向で恒温変態条件
（温度、時間）に差が生じてミクロ的な強度バラツキを
生じる。冷却速度が５℃／秒を超えると上記現象が生じ
るため、冷却速度は５℃／秒以下とした。When cooling a steel pipe, a temperature distribution always occurs in the thickness direction, and the cooling rate increases at the surface. As the cooling rate increases, bainite is generated, and not only the original isothermal transformation cannot be performed, but also the speed difference with the least cooled part increases, resulting in a difference in isothermal transformation conditions (temperature, time) in the thickness direction. This causes micro-scale variation in strength. When the cooling rate exceeds 5 ° C./sec, the above phenomenon occurs. Therefore, the cooling rate was set to 5 ° C./sec or less.
【００２４】恒温変態処理は、Ａｅ1点以下の温度で施
すこととしている。この発明の鋼材のＡｅ1点は、７８
０℃が最大であるので、これを上限値とした。また、６
５０℃未満の温度では、所望の強度を得るのに著しく長
時間の保持が必要となるが、その効果は小さい。恒温変
態処理の保持時間は、０．２５時間未満では、空冷後に
未変態オーステナイトからマルテンサイトやベイナイト
が生成し強度が向上しない。また、２．０時間を超える
と強度低下が生じることとなる。このため、恒温温度は
６５０〜７８０℃、恒温時間は０．２５〜２．０時間と
した。The constant temperature transformation is performed at a temperature of one point Ae or less. The Ae 1 point of the steel material of the present invention is 78
Since 0 ° C. is the maximum, this was set as the upper limit. Also, 6
If the temperature is lower than 50 ° C., a very long holding time is required to obtain the desired strength, but the effect is small. If the holding time of the isothermal transformation is less than 0.25 hours, martensite and bainite are formed from untransformed austenite after air cooling, and the strength is not improved. If the time exceeds 2.0 hours, the strength is reduced. For this reason, the constant temperature was set at 650 to 780 ° C., and the constant temperature was set at 0.25 to 2.0 hours.
【００２５】この発明の合金鋼鋼管の製造方法は、前記
所定の成分組成の鋼片を、図１に示すとおり、１０５０
〜１２８０℃の温度範囲に加熱してピアサー、マンドレ
ルミルおよびサイザーを用い、仕上温度７５０℃以上で
熱間圧延したのち、直ちに８００〜１０５０℃の温度範
囲に再加熱し、次いで５℃／秒以下の冷却速度で恒温温
度の６５０〜７８０℃となし、０．２５〜２．０時間保
持して恒温変態処理することによって、調質熱処理材と
同等の引張特性を付与できると共に、スケール生成量を
調質熱処理に比較して極めて大幅に低減できる。In the method for manufacturing an alloy steel pipe according to the present invention, as shown in FIG.
After heating to a temperature range of up to 1280 ° C and hot rolling at a finishing temperature of 750 ° C or higher using a piercer, a mandrel mill and a sizer, immediately reheating to a temperature range of 800 to 1050 ° C, and then 5 ° C / sec or less A constant temperature of 650 to 780 ° C. at a cooling rate of 0.25 to 2.0 hours and a constant temperature transformation treatment to provide a tensile property equivalent to that of the heat-treated heat-treated material and to reduce the scale generation amount The temperature can be significantly reduced as compared with the refining heat treatment.
【００２６】[0026]
【実施例】通常の溶解法および鋳造法により表１に示す
成分組成を有する外径２２５ｍｍ、長さ２ｍの本発明鋼
片Ａ〜Ｌと、構成成分のうち表１に＊印で示す成分含有
率がこの発明鋼片の範囲から外れた成分組成を有する比
較鋼片Ｍ〜Ｒを調整し、これらの鋼片Ａ〜Ｌを素材とし
て用い、ピアサー、マンドレルミルおよびサイザーから
なる熱間継目無鋼管製造設備を使用し、表２に示す各製
造条件で外径１７７．８ｍｍ、肉厚１６ｍｍの本発明法
の継目無鋼管を製造した。また、比較鋼片Ｍ〜Ｒおよび
本発明鋼片Ａ、Ｉを素材として用い、ピアサー、マンド
レルミルおよびサイザーからなる熱間継目無鋼管製造設
備を使用し、表３に示す各製造条件で外径１７７．８ｍ
ｍ、肉厚１６ｍｍの比較法の継目無鋼管を製造した。そ
して、得られた各継目無鋼管からそれぞれ試験片を採取
して引張特性を測定すると共に、スケール付着厚さを測
定した。その結果をそれぞれ表４および表５に示す。な
お、表３中の＊印は、この発明の範囲外を示し、また、
オフライン熱処理は、熱間加工した継目無鋼管を、室温
から９２０℃に加熱して０．１７時間保持したのち、５
℃／秒の冷却速度で７２５℃まで冷却し、７２５℃で
０．７５時間保持して恒温変態処理した。EXAMPLES Steel slabs A to L of the present invention having an outer diameter of 225 mm and a length of 2 m having the component compositions shown in Table 1 by ordinary melting and casting methods, and containing the components indicated by * in Table 1 among the constituent components The comparative steel slabs M to R having a component ratio out of the range of the steel slab of the present invention were adjusted, and these steel slabs A to L were used as materials, and a hot seamless steel pipe comprising a piercer, a mandrel mill, and a sizer Using the manufacturing equipment, a seamless steel pipe having an outer diameter of 177.8 mm and a wall thickness of 16 mm according to the present invention was manufactured under the manufacturing conditions shown in Table 2. In addition, using the comparative steel slabs M to R and the steel slabs A and I of the present invention as raw materials, using a hot seamless steel pipe manufacturing facility including a piercer, a mandrel mill and a sizer, under the manufacturing conditions shown in Table 3, 177.8m
m, a seamless steel pipe having a wall thickness of 16 mm according to a comparative method was manufactured. Then, a test piece was taken from each of the obtained seamless steel pipes, the tensile properties were measured, and the scale adhesion thickness was measured. The results are shown in Tables 4 and 5, respectively. In addition, * mark in Table 3 shows that it is out of the range of this invention,
The off-line heat treatment is performed by heating a hot-worked seamless steel pipe from room temperature to 920 ° C. and keeping it for 0.17 hours.
The sample was cooled to 725 ° C. at a cooling rate of ° C./sec, and kept at 725 ° C. for 0.75 hours to perform a constant temperature transformation treatment.
【００２７】[0027]
【表１】 [Table 1]
【００２８】[0028]
【表２】 [Table 2]
【００２９】[0029]
【表３】 [Table 3]
【００３０】[0030]
【表４】 [Table 4]
【００３１】[0031]
【表５】 [Table 5]
【００３２】表４、表５に示すとおり、この発明方法に
よって製造した試験Ｎｏ．１〜２３の継目無鋼管は、従
来の調質熱処理を必要とすることなく、熱間圧延後イン
ラインで直ちに再加熱して恒温温度まで冷却して恒温変
態処理することによって、従来の調質熱処理した試験Ｎ
ｏ．４０、４１の継目無鋼管と同等の強度、延性を有し
ており、しかも、表面の付着スケールを極めて大幅に低
減することができる。これに対し試験Ｎｏ．２４〜２９
の比較鋼片から製造した継目無鋼管および試験Ｎｏ．３
０〜３９の本発明方法で規定の製造条件を満足させない
継目無鋼管は、耐力２５０〜３５０Ｎ／ｍｍ2、引張強
さ４５０〜５５０Ｎ／ｍｍ2といった強度要求に対して
低めまたは高めとなっており、例え、耐力、引張強さを
満足しても、スケール厚さが３倍以上厚く付着してい
る。As shown in Tables 4 and 5, Test Nos. The seamless steel pipes Nos. 1 to 23 can be reheated immediately in-line after hot rolling, cooled to a constant temperature and subjected to a constant temperature transformation treatment without the need for the conventional heat treatment. Test N
o. It has the same strength and ductility as the seamless steel pipes No. 40 and 41, and also can greatly reduce the adhesion scale on the surface. In contrast, Test No. 24-29
And a seamless steel pipe manufactured from the comparative billet of Test No. 3
Seamless steel pipe which does not satisfy the manufacturing conditions defined in the present invention a method of 0-39 is a low or elevated relative strength 250~350N / mm 2, the strength required like tensile strength 450~550N / mm 2 Even if the proof stress and the tensile strength are satisfied, the scale thickness is three times or more.
【００３３】[0033]
【発明の効果】この発明の合金鋼鋼管の製造方法は、調
質熱処理を必要とすることなく、調質熱処理材と同等の
引張特性を有し、しかも、スケール生成量の極めて少な
い鋼管を製造することができ、デスケール処理を軽減す
ることができる。According to the method for manufacturing an alloy steel pipe of the present invention, a steel pipe having the same tensile properties as a heat-treated heat-treated material and having a very small amount of scale is produced without the need for a heat-treated heat treatment. And the descaling process can be reduced.
【図１】この発明の合金鋼鋼管の製造方法の温度条件の
推移を示す模式図である。FIG. 1 is a schematic diagram showing transition of temperature conditions in a method for manufacturing an alloy steel pipe of the present invention.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C21D 8/00 - 8/10 C22C 38/00 - 38/60 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) C21D 8/00-8/10 C22C 38/00-38/60
Claims (2)
０２〜０．６０％、Ｍｎ：０．３〜１．８％、Ｃｒ：
０．２〜１０．０％、Ｍｏ：０．２〜１．５％を含有
し、残部がＦｅと不可避的不純物からなる組成を有する
鋼片を、１０５０〜１２８０℃の温度範囲に加熱し、ピ
アサー、マンドレルおよびサイザーを用いて穿孔と７５
０℃以上の仕上げ温度での熱間圧延を行ったのち、８０
０〜１０５０℃の温度範囲に再加熱して恒温温度まで５
℃／秒以下の冷却速度で冷却し、６５０〜７８０℃の温
度範囲で０．２５〜２．０時間恒温処理したのち空冷す
ることを特徴とする合金鋼鋼管の製造方法。1. C: 0.05-0.35%, Si: 0.
02-0.60%, Mn: 0.3-1.8%, Cr:
A steel slab containing 0.2 to 10.0%, Mo: 0.2 to 1.5%, and the balance being Fe and unavoidable impurities, is heated to a temperature range of 1050 to 1280 ° C, Piercing and piercing with piercers, mandrels and sizers
After hot rolling at a finishing temperature of 0 ° C or higher, 80
Reheat to a temperature range of 0 to 1050 ° C and reach a constant temperature of 5
A method for producing an alloy steel pipe, comprising cooling at a cooling rate of not more than ° C / sec, performing a constant temperature treatment in a temperature range of 650 to 780 ° C for 0.25 to 2.0 hours, and then air cooling.
０２〜０．６０％、Ｍｎ：０．３〜１．８％、Ｃｒ：
０．２〜１０．０％、Ｍｏ：０．２〜１．５％を含み、
さらに、Ｖ：０．０１〜０．１５％、Ｎｂ：０．０１〜
０．１０％、Ｔｉ：０．０１〜０．１０％のうちの１種
または２種以上を含有し、残部がＦｅと不可避的不純物
からなる組成を有する鋼片を、１０５０〜１２８０℃の
温度範囲に加熱し、ピアサー、マンドレルおよびサイザ
ーを用いて穿孔と７５０℃以上の仕上げ温度での熱間圧
延を行ったのち、８００〜１０５０℃の温度範囲に再加
熱して恒温温度まで５℃／秒以下の冷却速度で冷却し、
６５０〜７８０℃の温度範囲で０．２５〜２．０時間恒
温処理したのち空冷することを特徴とする合金鋼鋼管の
製造方法。2. C: 0.05 to 0.35%, Si: 0.
02-0.60%, Mn: 0.3-1.8%, Cr:
0.2 to 10.0%, Mo: 0.2 to 1.5%,
Further, V: 0.01 to 0.15%, Nb: 0.01 to
A steel slab containing one or more of 0.10% and Ti: 0.01 to 0.10% and having a balance of Fe and inevitable impurities at a temperature of 1050 to 1280 ° C. After heating to a range, piercing using a piercer, mandrel and sizer, and performing hot rolling at a finishing temperature of 750 ° C. or higher, reheating to a temperature range of 800 to 1050 ° C. to a constant temperature of 5 ° C./sec. Cool at the following cooling rate,
A method for producing an alloy steel pipe, comprising: performing a constant temperature treatment in a temperature range of 650 to 780 ° C. for 0.25 to 2.0 hours, followed by air cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09601896A JP3214348B2 (en) | 1996-03-25 | 1996-03-25 | Manufacturing method of alloy steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09601896A JP3214348B2 (en) | 1996-03-25 | 1996-03-25 | Manufacturing method of alloy steel pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09263830A JPH09263830A (en) | 1997-10-07 |
| JP3214348B2 true JP3214348B2 (en) | 2001-10-02 |
Family
ID=14153533
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09601896A Expired - Lifetime JP3214348B2 (en) | 1996-03-25 | 1996-03-25 | Manufacturing method of alloy steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3214348B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102716910A (en) * | 2012-06-29 | 2012-10-10 | 衡阳华菱钢管有限公司 | Steel tube for die-casting die and preparation method thereof |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002146487A (en) * | 2000-09-01 | 2002-05-22 | Daido Steel Co Ltd | Steel for shaft |
| CN102952994B (en) * | 2011-08-25 | 2015-08-26 | 宝山钢铁股份有限公司 | Refractory anti-seismic construction steel and production method thereof |
| JPWO2015005119A1 (en) * | 2013-07-09 | 2017-03-02 | 新日鐵住金株式会社 | Manufacturing method of high Cr steel pipe |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57110617A (en) * | 1980-12-29 | 1982-07-09 | Kawasaki Steel Corp | Heat treatment of cr-mo steel |
| JPH0735547B2 (en) * | 1988-04-22 | 1995-04-19 | 川崎製鉄株式会社 | Method for producing high-chromium seamless steel pipe with excellent high-temperature strength |
| JPH046218A (en) * | 1990-04-24 | 1992-01-10 | Nkk Corp | Production of seamless cr-mo steel tube |
| JPH07278656A (en) * | 1994-04-04 | 1995-10-24 | Nippon Steel Corp | Production of low yield ratio high tensile strength steel |
-
1996
- 1996-03-25 JP JP09601896A patent/JP3214348B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102716910A (en) * | 2012-06-29 | 2012-10-10 | 衡阳华菱钢管有限公司 | Steel tube for die-casting die and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09263830A (en) | 1997-10-07 |
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