JP3117529B2 - Mo-based ultra-high tensile ERW steel pipe with excellent ductility - Google Patents
Mo-based ultra-high tensile ERW steel pipe with excellent ductilityInfo
- Publication number
- JP3117529B2 JP3117529B2 JP04049419A JP4941992A JP3117529B2 JP 3117529 B2 JP3117529 B2 JP 3117529B2 JP 04049419 A JP04049419 A JP 04049419A JP 4941992 A JP4941992 A JP 4941992A JP 3117529 B2 JP3117529 B2 JP 3117529B2
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- steel pipe
- ductility
- strength
- electric resistance
- pipe
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Description
【０００１】[0001]
【産業上の利用分野】本発明は自動車等の構造部材に使
用される超高張力電縫鋼管、特にドア補強用の引張り強
度が１５０ｋｇｆ／ｍｍ2 以上、伸びが１０％以上であ
る経済的で延性の優れたＭｏ系超高張力電縫鋼管に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high tensile strength electric resistance welded steel tube used for structural members of automobiles and the like, particularly economical one having a tensile strength for reinforcing a door of 150 kgf / mm 2 or more and an elongation of 10% or more. The present invention relates to a Mo-based ultra-high tensile electric resistance welded steel pipe having excellent ductility.
【０００２】[0002]
【従来の技術】自動車等の構造部材については、燃費向
上・環境対策のために徹底した軽量化が検討されてお
り、安全性との両立を図る方策の一つとして一部部材で
は１５０ｋｇｆ／ｍｍ2 を超える超高張力鋼管が採用さ
れつつある。2. Description of the Related Art Thorough reduction in weight of structural members of automobiles and the like has been studied to improve fuel efficiency and environmental measures. One of the measures for achieving compatibility with safety is 150 kgf / mm for some members. More than two ultra-high tensile steel tubes are being adopted.
【０００３】自動車ドア補強用の鋼管材料としては、特
開平３−１２２２１９号公報等に記載されているように
電縫造管後調質即ち焼入または焼入焼戻をする方法、お
よび特開平３−１４０４４１のような所定の低合金鋼を
焼準する方法が一般的である。[0003] As a steel pipe material for reinforcing an automobile door, a method of tempering, ie, quenching or quenching and tempering after ERW pipe, as described in JP-A-3-122219, and the like, and JP-A-Hei. A method of normalizing a predetermined low alloy steel such as 3-140441 is generally used.
【０００４】[0004]
【発明が解決しようとする課題】従来の技術としては、
従来の技術の項に記載したように２つのタイプがある。
まず、特開平３−１２２２１９号公報等に記載されてい
るような方法では、ピース毎に処理する特殊な熱処理設
備を必要とし、寸法形状、材質の確保に特別の注意が必
要であり、生産性が低く、設備投資・生産性の点で著し
くコストの高いものとなっている。更により剛性の高い
構造部材として注目されている角型鋼管、異形鋼管の製
造法としては寸法精度の確保上、不適当である。[0005] As a conventional technology,
There are two types as described in the background section.
First, the method described in Japanese Patent Application Laid-Open No. 3-122219 requires special heat treatment equipment for processing each piece, and requires special attention to secure dimensions, shape, and material. Cost is extremely high in terms of capital investment and productivity. Furthermore, it is unsuitable as a method for producing square steel pipes and deformed steel pipes, which are attracting attention as structural members having higher rigidity, in terms of securing dimensional accuracy.
【０００５】次に、特開平３−１４０４４１のような所
定の低合金鋼を焼準する方法は、上記の焼き入れタイプ
の問題点を解消できるが成分によっては材料費が高くな
り、延性が悪化する場合がある。特開平３−１４０４４
１の場合はＭｎが３％を越えており転炉での製造が事実
上不可能であり、また、Ｎｉ等の高価な成分が含まれて
いる。また、鋼管の製造方法および伸びについては明か
にされていない。本発明は焼準タイプで従来法よりも経
済的で、製造も容易であり、引張り強度が１５０ｋｇｆ
／ｍｍ2 以上、かつ延性が１０％以上の優れたＭｏ系超
高張力電縫鋼管を提供することを目的にするものであ
る。[0005] Next, a method of normalizing a predetermined low alloy steel as disclosed in Japanese Patent Application Laid-Open No. 3-140441 can solve the above-mentioned problems of the quenching type, but the material cost increases and the ductility deteriorates depending on the components. May be. JP-A-3-14044
In the case of 1, the Mn exceeds 3%, making it practically impossible to use a converter, and contains expensive components such as Ni. In addition, the production method and elongation of the steel pipe are not disclosed. The present invention is a normalizing type, which is more economical than the conventional method, easy to manufacture, and has a tensile strength of 150 kgf.
It is an object of the present invention to provide an excellent Mo-based ultra-high tensile electric resistance welded steel pipe having a ductility of not less than / mm 2 and a ductility of not less than 10%.
【０００６】[0006]
【課題を解決するための手段】本発明の要旨とするとこ
ろは下記のとおりである。The gist of the present invention is as follows.
【０００７】（１） 成分組成が重量でＣ：０．１５〜
０．４０％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：２．
０〜３．０％、Ｐ：０．００５〜０．０２０％、Ｓ：
０．０００５〜０．００６０％、Ａｌ：０．０１〜０．
００３０％、Ｂ：０．００１０〜０．００３０％、Ｎ：
０．００２〜０．００５％、Ｍｏ：０．３〜１．５％を
含有させる残部Ｆｅ及び不可避的元素よりなる丸形状の
電縫鋼管において、造管後に熱処理として、Ａｃ 3 変態
点以上に加熱してオーステナイト化した後に冷却し、フ
ェライトの生成を抑制し、一部マルテンサイトを含むベ
イナイトのミクロ組織とする焼準を行うことを特徴とす
る延性の優れたＭｏ系超高張力電縫鋼管。(1) The composition of the component is C: 0.15 by weight
0.40%, Si: 0.05 to 0.50%, Mn: 2.
0 to 3.0%, P: 0.005 to 0.020%, S:
0.0005-0.0060%, Al: 0.01-0.
0030%, B: 0.0010 to 0.0030%, N:
In a round-shaped ERW steel pipe composed of 0.002 to 0.005% and Mo: 0.3 to 1.5%, the balance being Fe and an unavoidable element , the heat treatment is performed after pipe formation , and the Ac 3 transformation is performed.
After heating to austenite by heating above
Suppresses the formation of cellite
Excellent Mo-based ultra-high-tension electric resistance welded steel pipe of ductility, characterized in that intends line a normalizing of the microstructure of bainite.
【０００８】（２） 成分組成が重量でＣ：０．１５〜
０．４０％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：２．
０〜３．０％、Ｐ：０．００５〜０．０２０％、Ｓ：
０．０００５〜０．００６０％、Ａｌ：０．０１〜０．
００８％、Ｂ：０．００１０〜０．００３０％、Ｎ：
０．００２〜０．００５％、Ｍｏ：０．３〜１．５％
に、Ｔｉ：０．０１〜０．２０％、Ｎｂ：０．０１〜
０．２０％以下を１種以上を含有させる残部Ｆｅ及び不
可避的元素よりなる丸形状の電縫鋼管において、熱処理
として、Ａｃ 3 変態点以上に加熱してオーステナイト化
した後に冷却し、フェライトの生成を抑制し、一部マル
テンサイトを含むベイナイトのミクロ組織とする焼準を
行うことを特徴とする延性の優れたＭｏ系超高張力電縫
鋼管。(2) C: 0.15 to 5% by weight
0.40%, Si: 0.05 to 0.50%, Mn: 2.
0 to 3.0%, P: 0.005 to 0.020%, S:
0.0005-0.0060%, Al: 0.01-0.
008%, B: 0.0010 to 0.0030%, N:
0.002-0.005%, Mo: 0.3-1.5%
In addition, Ti: 0.01 to 0.20%, Nb: 0.01 to
As a heat treatment , austenitizing by heating to a temperature higher than the Ac 3 transformation point in a round ERW steel pipe made of the balance Fe and an unavoidable element containing 0.20% or less of one or more kinds .
After cooling, the formation of ferrite is suppressed and
Excellent Mo-based ultra-high-tensile ERW pipe ductility, characterized in that intends <br/> rows normalizing to microstructure of bainite including ten sites.
【０００９】（３） 前記（１）または前記（２）項の
成分組成よりなる角形または異形の電縫鋼管において、
熱処理として、Ａｃ 3 変態点以上に加熱してオーステナ
イト化した後に冷却し、フェライトの生成を抑制し、一
部マルテンサイトを含むベイナイトのミクロ組織とする
焼準を行うことを特徴とする延性の優れたＭｏ系超高張
力電縫鋼管。(3) A square or deformed ERW steel pipe having the composition described in the above item (1) or (2),
As heat treatment, it is heated to more than Ac 3 transformation point austenite
After cooling, the formation of ferrite is suppressed,
Excellent Mo-based ultra-high-tensile ERW pipe ductility, characterized in that intends rows <br/> sintered semi to microstructure of bainite including parts martensite.
【００１０】以下に本発明を詳細に説明する。最初に本
発明に使用する鋼板の成分のうち請求項１〜３に共通の
成分について限定理由を説明する。Hereinafter, the present invention will be described in detail. First, among the components of the steel sheet used in the present invention, the reasons for limiting the components common to claims 1 to 3 will be described.
【００１１】Ｃ量は少なければ延性が良好であり、加工
性に優れているが、所要の強度が得られないことから下
限を０．１５％とした。又、０．４０％を超えると造管
時の成形性等の冷間加工性及び靭性が低下する傾向にあ
り、又、電縫鋼管の造管溶接時に熱影響部が硬化し、切
断等で支障を来すことから、上限を０．４０％とした。The lower the C content, the better the ductility and the excellent workability, but the required lower strength cannot be obtained, so the lower limit was made 0.15%. On the other hand, if it exceeds 0.40%, the cold workability and toughness such as formability at the time of pipe forming tend to decrease, and the heat-affected zone hardens at the time of pipe forming welding of ERW steel pipes, resulting in cutting. The upper limit was set to 0.40% because it would cause trouble.
【００１２】Ｓｉはキルド鋼の場合、０．０５％未満に
おさえることは製鋼技術上難しく、又、０．５０％を超
えると電縫溶接性および靭性が悪化するため、０．５０
％を上限とした。[0012] In the case of killed steel, it is difficult to suppress the content of Si to less than 0.05% in view of steelmaking technology, and if it exceeds 0.50%, the resistance to electric resistance welding and toughness deteriorate.
% As the upper limit.
【００１３】Ｍｎは、強度と延性のバランスが良く、強
度を上げ、伸びを確保するためには最低２．０％以上必
要である。又、３．０％を超えると転炉での溶製が極め
て困難になることから、下限を２．０％、上限を３．０
％とした。Mn has a good balance between strength and ductility, and must be at least 2.0% in order to increase strength and secure elongation. If it exceeds 3.0%, melting in the converter becomes extremely difficult, so the lower limit is 2.0% and the upper limit is 3.0.
%.
【００１４】Ｐは製鋼時不可避的に混入する元素である
が、０．００５％未満にすることは製鋼技術上難しく、
０．０２０％を超えると特に超高張力鋼管の電縫溶接時
に溶接部割を発生しやすいため、下限を０．００５％、
上限を０．０２０％とした。[0014] P is an element inevitably mixed during steel making, but it is difficult to make the content less than 0.005% due to steel making technology.
If the content exceeds 0.020%, particularly in the case of electric resistance welding of ultra-high tensile steel pipe, a welded portion is likely to be generated.
The upper limit was made 0.020%.
【００１５】ＳもＰ同様製鋼時不可避的に混入する元素
であり、０．０００５％未満にすることは製鋼技術上難
しく、０．００６０％を超えると電縫溶接時に溶接部割
を発生しやすいため、下限を０．０００５％、上限を
０．００６０％とした。Ｓによる電縫溶接時の割を更に
抑制するには、ＭｎＳを形態制御する元素であるＣａを
添加してもよい。S is also an element inevitably mixed during steel making like P, and it is difficult to make the content less than 0.0005% in terms of steel making technology, and if it exceeds 0.0060%, a weld portion is likely to be generated during electric resistance welding. Therefore, the lower limit is made 0.0005% and the upper limit is made 0.0060%. In order to further suppress cracking during electric resistance welding by S, Ca which is an element for controlling the form of MnS may be added.
【００１６】Ａｌはキルド鋼の場合、０．０１％未満に
おさえることは製鋼技術上難しく、又、０．０８％を超
えると鋳片の割れ、酸化物系巨大介在物形成による内質
欠陥等をひきおこしやすいため、下限を０．０１％、上
限を０．０８％とした。In the case of killed steel, it is difficult for the steelmaking technology to suppress the content of Al to less than 0.01%, and if it exceeds 0.08%, cracks in slabs, internal defects due to formation of oxide-based giant inclusions, etc. Therefore, the lower limit was set to 0.01% and the upper limit was set to 0.08%.
【００１７】Ｂは冷却過程においてフェライト変態を遅
らせて高強度変態組織を得るために必須の元素である
が、本発明鋼の成分組成においても０．００１０％未満
では強度不足となり、０．００３０％を超えるとＢｏｒ
ｏｎ Ｃｏｎｓｔｉｔｕｅｎｔが生成して延靭性が著し
く低下するため、下限を０．００１０％、上限を０．０
０３０％とした。B is an essential element for delaying ferrite transformation in the cooling process to obtain a high-strength transformed structure. However, even in the composition of the steel of the present invention, if the content is less than 0.0010%, the strength becomes insufficient, and 0.0030% Beyond Bor
Since on-constituent is generated and ductility is significantly reduced, the lower limit is 0.0010% and the upper limit is 0.0%.
030%.
【００１８】Ｎは製鋼時不可避的に混入する元素である
が、０．００２％未満におさえることは製鋼技術上難し
く、０．００５％を超えるとＴｉ、Ｂの強度上昇効果を
阻害して強度不足をひきおこすため、下限を０．００２
％、上限を０．００５％とした。N is an element that is inevitably mixed during steel making, but it is difficult to control the content to less than 0.002% from the viewpoint of steel making technology. If it exceeds 0.005%, the strength increasing effect of Ti and B is hindered. 0.002 lower limit to cause shortage
%, And the upper limit was made 0.005%.
【００１９】Ｍｏはフェライト変態を抑制し、細粒化に
効果があり、析出強化する特徴を有し、造管前の強度に
ほとんど関係なく、造管後の焼準の熱処理により一部マ
ルテンサイトを含むベイナイト主体の組織になるため、
強度を上げるのに有効である。この目的のため、Ｍｏは
０．３％以上を含有させる。しかし、１．５％を超えて
添加しても効果の向上が少なく、延性の劣化を招くこと
から、上限を１．５％とした。Mo suppresses ferrite transformation, has an effect on grain refinement, and has the feature of strengthening precipitation. Mo has little martensite by normalizing heat treatment after pipe formation, regardless of the strength before pipe formation. To become a bainite-based organization,
It is effective to increase strength. For this purpose, Mo contains at least 0.3%. However, even if added over 1.5%, the effect is little improved and ductility is deteriorated, so the upper limit was made 1.5%.
【００２０】Ｔｉ、Ｎｂについては、Ｍｏと同様に熱間
圧延での未再結晶γ域を広げるために細粒化に効果があ
り、析出強化し、いずれも鋼材の強度を上昇させる元素
であり、超高張力電縫鋼管の製造に有効であるため、
０．０１％以上を含有させる。しかし、０．２０％を越
えると延靭性を害するのでＴｉ、Ｎｂの下限は０．０１
％、上限をそれぞれ、０．２０％とした。Ti and Nb, like Mo, are effective in grain refinement by expanding the unrecrystallized γ region in hot rolling, and are elements that strengthen precipitation and increase the strength of steel materials. , Because it is effective in the production of ultra-high tensile ERW steel pipes,
0.01% or more is contained. However, if it exceeds 0.20%, the ductility is impaired, so the lower limits of Ti and Nb are 0.01%.
% And the upper limit were each set to 0.20%.
【００２１】次に製造工程について説明する。本発明の
製造工程を図１に示す。本発明に従い、上記成分の鋼を
熱間板厚圧延時に９５０℃以下Ａｒ3 変態点以上で仕上
圧延を終了することが望ましい。これは、特に靭性の改
善が望まれる場合、および低強度の鋼板を得て造管を容
易にする場合に必要である。９５０℃超では未再結晶域
での圧延が存在しないため強度・延靭性が劣化し、Ａｒ
3 変態点未満では２相域圧延によって強度は上昇するが
延靭性が著しく低下する。よって上記成分の鋼を熱間板
厚圧延時に９５０℃以下Ａｒ3 変態点以上で仕上圧延を
終了し引続き本発明の条件で巻取ることによって、後工
程での製造が容易な低強度で延性の優れた材質とするこ
とができる。Next, the manufacturing process will be described. FIG. 1 shows the manufacturing process of the present invention. According to the present invention, it is desirable that the finish rolling of the steel having the above composition be completed at a temperature of 950 ° C. or lower and an Ar 3 transformation point or higher during hot plate rolling. This is necessary especially when improvement in toughness is desired and when obtaining a low-strength steel plate to facilitate pipe making. If the temperature exceeds 950 ° C., there is no rolling in the non-recrystallized region, so that the strength and ductility are deteriorated.
If the transformation point is less than 3 , the strength is increased by the two-phase rolling, but the ductility is significantly reduced. Therefore, by finishing the finish rolling at 950 ° C. or lower at the Ar 3 transformation point or higher and hot-rolling the steel having the above-mentioned components at the Ar 3 transformation point or lower at the time of hot plate rolling, low-strength and ductile, which can be easily manufactured in the subsequent process, Excellent material can be used.
【００２２】巻取温度は６００℃以上で巻取れば、コイ
ル内の冷却速度は炉冷に近いため、Ｍｏ等の析出は過時
効し、フェライトが析出して比較的に低強度で延性のあ
る鋼板を製造できる。このように製造された鋼板は電縫
管に造管するに十分な延性を有する。If the coiling temperature is 600 ° C. or higher, the cooling rate in the coil is close to the furnace cooling, so that the precipitation of Mo and the like is overaged, and the ferrite is precipitated to have relatively low strength and ductility. Can manufacture steel sheet. The steel plate manufactured in this manner has sufficient ductility to form an ERW pipe.
【００２３】造管後に熱処理として焼準を行なう。これ
はＡｃ3 点以上に加熱してオーステナイト化した後に空
冷並の冷却で、フェライトの生成を抑制し、一部マルテ
ンサイトを含むベイナイト主体の組織とし、強度上昇を
はかる。焼準温度は温度のばらつきを考慮してＡｃ3 ＋
２０℃以上とし、上限は細粒を保ち強度延性のバランス
を確保するため、Ａｃ3 ＋７０℃以下が望ましい。ま
た、ここでの空冷は３００℃までの冷却速度が１０〜１
５０℃／分の範囲である。Ａｃ3 点未満の熱処理では上
記の効果が得られず所定の強度が得られない。After pipe forming, normalizing is performed as heat treatment. In this method, austenite is formed by heating to a temperature of 3 or more points of temperature, followed by air-cooling, thereby suppressing the formation of ferrite, forming a bainite-based structure partially containing martensite, and increasing the strength. The normalizing temperature is set to Ac 3 + in consideration of temperature variation.
The upper limit is preferably set to 20 ° C. or higher, and the upper limit is set to Ac 3 + 70 ° C. or lower in order to maintain fine grains and secure the balance of strength ductility. The air cooling here is performed at a cooling rate up to 300 ° C.
It is in the range of 50 ° C./min. If the heat treatment is performed with less than Ac 3 points, the above effects cannot be obtained and the predetermined strength cannot be obtained.
【００２４】以上本発明の請求項１および請求項２に記
載の電縫鋼管について説明したが、請求項３記載の電縫
鋼管でもよい。図２は請求項３に記載の電縫鋼管を製造
する工程を示す。このように冷間絞り加工を付加するこ
とにより、曲げ強度の優れた角型鋼管、異形鋼管の製造
が可能である。角型および異形鋼管の形状例を図３に示
す。冷間絞り加工は、ダイス引き抜きによる方法とロー
ルフォーミングによる方法がある。素管熱処理は造管時
の冷間加工による加工歪を除去し、電縫溶接部の焼き入
れ硬化部を軟化し、冷間絞り加工性を改善するためであ
り、６００℃以上の軟化焼鈍または焼準を行なう。冷間
絞り後の仕上げ熱処理は、冷間加工歪を除去し、強度延
性のバランスを改善するために焼準を行なう。ただし、
素管熱処理として焼準を行なった場合は既に強度は十分
に上昇しているため、冷間絞り後の仕上げ熱処理は焼鈍
を行なう。このようにすれば冷間加工による加工硬化量
と焼鈍温度の組合せで適当な強度−延性バランスが得ら
れる。焼鈍温度は冷間加工率によるが４５０℃以上から
効果がある。The electric resistance welded steel pipe according to claims 1 and 2 of the present invention has been described above, but the electric resistance welded steel pipe according to claim 3 may be used. FIG. 2 shows a step of manufacturing the electric resistance welded steel pipe according to the third aspect. By adding cold drawing in this way, it is possible to manufacture square steel pipes and deformed steel pipes having excellent bending strength. FIG. 3 shows examples of the shape of the square and deformed steel pipes. Cold drawing includes a method by die drawing and a method by roll forming. The pipe heat treatment is for removing working strain due to cold working at the time of pipe forming, softening the quenched and hardened part of the electric resistance welded part, and improving cold drawing workability. Perform normalization. In the finishing heat treatment after the cold drawing, normalizing is performed to remove cold working strain and improve the balance of strength ductility. However,
When normalizing is performed as the shell heat treatment, the strength has already sufficiently increased, so that the finish heat treatment after cold drawing is performed by annealing. In this way, an appropriate strength-ductility balance can be obtained by a combination of the amount of work hardening by cold working and the annealing temperature. The annealing temperature depends on the cold working ratio, but is effective from 450 ° C. or higher.
【００２５】[0025]
【実施例】第１表に、サイズφ３４．１×ｔ２．０ｍｍ
の電縫鋼管を従来法および本発明法により製造した条件
および結果を示す。ここでの冷間伸管はダイスを用いて
角形状に空引きを行なった。従来法では１５０ｋｇｆ／
ｍｍ2 以上の強度を達成しても伸びは１０％を達成でき
ないが、本発明法では達成できる。また、本発明によれ
ば、造管後に焼準の熱処理を加えることによって母材部
・溶接部が均一で強度・延靭性バランスの優れた超高張
力電縫鋼管を得ることができる。熱処理後に更に冷間伸
管加工を付加することにより、各種寸法を容易に製造で
きるため、小ロット対応が可能であり、経済的である。
また、任意の断面に加工できるので曲げ加工性の優れた
角管等が製造可能である。更に冷間伸管後に焼準を行う
ことにより延性を増し、強度−延性バランスを改善す
る。また、必要に応じて、熱間板厚圧延における仕上圧
延温度および巻取温度を適正に制御することにより、低
強度で延性の優れた素材鋼板を製造して造管を容易にす
ることができる。なお、本実施例は冷間伸管を行った
が、要は冷間で絞り加工を行えば加工硬化により強度の
上昇が得られるため、ロールフォーミングによる絞り加
工でも同様な効果が得られる。EXAMPLES Table 1 shows the size φ34.1 × t2.0 mm.
The conditions and results of the ERW steel pipe manufactured by the conventional method and the method of the present invention are shown. Here, the cold drawing was performed in a rectangular shape using a die. 150 kgf /
Although the elongation cannot be attained by 10% even when the strength is at least 2 mm2, it can be achieved by the method of the present invention. Further, according to the present invention, it is possible to obtain an ultra-high tensile strength electric resistance welded steel pipe having a uniform base material portion and a welded portion and an excellent balance of strength and ductility by applying normalizing heat treatment after pipe forming. By adding a cold drawing process after the heat treatment, various dimensions can be easily manufactured, so that a small lot can be handled and it is economical.
Further, since it can be processed into an arbitrary cross section, a square tube or the like having excellent bending workability can be manufactured. Further, by performing normalizing after cold drawing, ductility is increased, and strength-ductility balance is improved. In addition, if necessary, by appropriately controlling the finish rolling temperature and the winding temperature in the hot thickness rolling, it is possible to produce a low-strength, excellent ductility material steel sheet and facilitate pipe making. . In this example, cold drawing was performed. However, if the drawing is performed cold, the strength can be increased by work hardening. Therefore, the same effect can be obtained by the drawing by roll forming.
【００２６】[0026]
【表１】 [Table 1]
【００２７】[0027]
【表２】 [Table 2]
【００２８】[0028]
【発明の効果】本発明によれば、電縫造管後に焼入れま
たは焼入れ、焼戻しをする必要が無く、ピース毎に処理
する特殊な熱処理設備を必要としないため、経済的であ
る。さらに、より剛性の高い構造部材として注目されて
いる角型鋼管、異形鋼管が容易に製造できる。また、従
来の焼準タイプに比較すると転炉で製造が可能であり、
Ｎｉ等の高価な合金が含まれていないので経済的であ
る。さらに、特性においても引張り強度１５０ｋｇｆ／
ｍｍ2 以上、伸び１０％以上の優れた強度−伸びバラン
スを有する超高張力電縫鋼管を製造することが可能にな
るので、産業上貢献するところが極めて大である。According to the present invention, there is no need to perform quenching, quenching, or tempering after the electric resistance welded pipe, and there is no need for a special heat treatment facility for processing each piece, which is economical. Furthermore, square steel pipes and deformed steel pipes, which are attracting attention as structural members having higher rigidity, can be easily manufactured. In addition, compared to conventional normalization type, it can be manufactured with a converter,
It is economical because it does not contain expensive alloys such as Ni. Further, the tensile strength is 150 kgf /
Since it becomes possible to manufacture an ultra-high tensile strength electric resistance welded steel tube having an excellent balance between strength and elongation of not less than 2 mm and elongation of not less than 10%, the industrial contribution is extremely large.
【図１】本発明の請求項１および請求項２に記載の方法
の製造工程図。FIG. 1 is a manufacturing process diagram of a method according to claims 1 and 2 of the present invention.
【図２】請求項３に記載の方法の製造工程を示す図。FIG. 2 is a view showing a manufacturing process of the method according to claim 3;
【図３】（ａ），（ｂ），（ｃ）は、本発明の角型およ
び異形鋼管の形状例を示す図。FIGS. 3 (a), (b), and (c) are views showing examples of shapes of a square and a deformed steel pipe of the present invention.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭55−2749（ＪＰ，Ａ) 特開 昭49−72119（ＪＰ，Ａ) 特開 平３−31442（ＪＰ，Ａ) 特開 平３−140441（ＪＰ，Ａ) 特開 昭62−263924（ＪＰ，Ａ) 特開 昭59−43821（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C22C 38/00 301 C21D 8/10 C21D 9/08 C22C 38/22 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-55-2749 (JP, A) JP-A-49-72119 (JP, A) JP-A-3-31442 (JP, A) JP-A-3-3 140441 (JP, A) JP-A-62-263924 (JP, A) JP-A-59-43821 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C22C 38/00 301 C21D 8/10 C21D 9/08 C22C 38/22
Claims (3)
管において、造管後に熱処理として、Ａｃ 3 変態点以上
に加熱してオーステナイト化した後に冷却し、フェライ
トの生成を抑制し、一部マルテンサイトを含むベイナイ
トのミクロ組織とする焼準を行うことを特徴とする延性
の優れたＭｏ系超高張力電縫鋼管。1. The component composition is C: 0.15 to 0.40% Si: 0.05 to 0.50% Mn: 2.0 to 3.0% P: 0.005 to 0.020% by weight S: 0.0005 to 0.0060% Al: 0.01 to 0.0030% B: 0.0010 to 0.0030% N: 0.002 to 0.005% Mo: 0.3 to 1.5% in electric resistance welded steel pipe made of the balance Fe and incidental element is contained, as a heat treatment after pipe formation, Ac 3 transformation point or more
After heating to austenite and cooling,
Bainite containing some martensite
Excellent Mo-based ultra-high-tension electric resistance welded steel pipe of ductility, characterized in that intends line a normalizing to the door of the microstructure.
の電縫鋼管において、熱処理として、Ａｃ 3 変態点以上
に加熱してオーステナイト化した後に冷却し、フ ェライ
トの生成を抑制し、一部マルテンサイトを含むベイナイ
トのミクロ組織とする焼準を行うことを特徴とする延性
の優れたＭｏ系超高張力電縫鋼管。2. The composition of the component is C: 0.15 to 0.40% Si: 0.05 to 0.50% Mn: 2.0 to 3.0% P: 0.005 to 0.020% by weight S: 0.0005 to 0.0060% Al: 0.01 to 0.008% B: 0.0010 to 0.0030% N: 0.002 to 0.005% Mo: 0.3 to 1.5% In a round ERW steel pipe made of a balance of Fe and an unavoidable element containing at least one of Ti: 0.01 to 0.20% and Nb: 0.01 to 0.20%, as heat treatment , 3 transformation points or more
Heated to cooling after austenitizing, full Erai
Bainite containing some martensite
Excellent Mo-based ultra-high-tension electric resistance welded steel pipe of ductility, characterized in that intends line a normalizing to the door of the microstructure.
形または異形の電縫鋼管において、熱処理として、Ａｃ
3 変態点以上に加熱してオーステナイト化した後に冷却
し、フェライトの生成を抑制し、一部マルテンサイトを
含むベイナイトのミクロ組織とする焼準を行うことを特
徴とする延性の優れたＭｏ系超高張力電縫鋼管。3. A square or deformed ERW steel pipe having the composition of claim 1 or 2, wherein the heat treatment is performed by ac treatment .
Cooling after heating to austenite by heating above 3 transformation point
To suppress the formation of ferrite and partially reduce martensite
Excellent Mo-based ultra-high-tensile ERW pipe ductility, characterized in that intends rows normalizing to microstructure of bainite including.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04049419A JP3117529B2 (en) | 1992-03-06 | 1992-03-06 | Mo-based ultra-high tensile ERW steel pipe with excellent ductility |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04049419A JP3117529B2 (en) | 1992-03-06 | 1992-03-06 | Mo-based ultra-high tensile ERW steel pipe with excellent ductility |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05247589A JPH05247589A (en) | 1993-09-24 |
| JP3117529B2 true JP3117529B2 (en) | 2000-12-18 |
Family
ID=12830557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04049419A Expired - Fee Related JP3117529B2 (en) | 1992-03-06 | 1992-03-06 | Mo-based ultra-high tensile ERW steel pipe with excellent ductility |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3117529B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3352938B2 (en) * | 1998-03-19 | 2002-12-03 | 株式会社神戸製鋼所 | High-strength hot-rolled steel sheet excellent in impact resistance and method for producing the same |
-
1992
- 1992-03-06 JP JP04049419A patent/JP3117529B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05247589A (en) | 1993-09-24 |
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