JPH11279697A - Resistance welded steel pipe excellent in workability, and its production - Google Patents
Resistance welded steel pipe excellent in workability, and its productionInfo
- Publication number
- JPH11279697A JPH11279697A JP8317198A JP8317198A JPH11279697A JP H11279697 A JPH11279697 A JP H11279697A JP 8317198 A JP8317198 A JP 8317198A JP 8317198 A JP8317198 A JP 8317198A JP H11279697 A JPH11279697 A JP H11279697A
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- workability
- steel pipe
- resistance welded
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、優れた加工性が要
求される自動車用、機械構造用電縫鋼管に関し、特定の
成分からなる鋼と、特定の熱延条件および高周波電縫溶
接条件により得られる加工性に優れた電縫鋼管とその製
造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric resistance welded steel pipe for an automobile or a machine structure requiring excellent workability. The invention relates to a steel comprising a specific component, specific hot rolling conditions and high frequency electric resistance welding conditions. The present invention relates to an electric resistance welded steel pipe having excellent workability and a method for producing the same.
【０００２】[0002]
【従来の技術】欧米において、自動車の軽量化と部品点
数削減によるコストダウンを目的としてハイドロフォ−
ム技術の実用化が行われている。日本においても次世代
自動車生産技術の中核の一つとして積極的な取り組みが
行われている。このような背景のもと電縫鋼管を素材と
し、ハイドロフォ−ムにより成形した足廻り部品および
ボディ−部品の適用が増加しつつある。ハイドロフォ−
ム用の電縫鋼管は複雑な加工に耐え得る良好な延性を有
することが重要である。2. Description of the Related Art In Europe and the United States, hydrophobes have been developed for the purpose of cost reduction by reducing the weight of automobiles and the number of parts.
System technology is being put to practical use. Active efforts are being made in Japan as one of the cores of next-generation vehicle production technology. Against this background, the application of underbody parts and body parts made of ERW steel tubes and formed by hydroforming is increasing. Hydropho
It is important that the ERW steel pipe for the rubber has good ductility that can withstand complicated processing.
【０００３】これまで同程度の強度でありながら延性を
向上させる、すなわち強度−延性バランスの向上を目的
とした研究開発が数多く行われてきた。過去において、
飛躍的に強度−延性バランスを向上させたのは、フェラ
イトとマルテンサイトの混合組織からなる、いわゆる二
相鋼である。例えば、特開昭５１−１２３１７号公報に
熱延後急冷することにより得られる二相鋼の技術、特公
昭５７−４５４５４号公報には連続焼鈍により得られる
技術がある。現在、二相鋼はその優れた特性を生かし、
自動車用等の材料の軽量化用途として注目されている。There have been many researches and developments aimed at improving ductility while maintaining the same strength, that is, improving strength-ductility balance. In the past,
What has drastically improved the strength-ductility balance is a so-called duplex stainless steel having a mixed structure of ferrite and martensite. For example, JP-A-51-12317 discloses a technique of duplex stainless steel obtained by hot-rolling followed by rapid cooling, and JP-B-57-45454 discloses a technique obtained by continuous annealing. Currently, duplex stainless steels take advantage of their excellent properties,
It is attracting attention as an application for reducing the weight of materials for automobiles and the like.
【０００４】[0004]
【発明が解決しようとする課題】ハイドロフォ−ム用の
電縫鋼管は複雑な加工に耐え得る良好な延性を有するこ
とが重要である。本発明は加工性に優れた電縫鋼管とそ
の製造方法を提供するものである。It is important that an ERW steel pipe for a hydroform has good ductility to withstand complicated machining. The present invention provides an electric resistance welded steel pipe excellent in workability and a method for manufacturing the same.
【０００５】[0005]
【課題を解決するための手段】本発明は、重量％で、
Ｃ：０．０２〜０．１５％、Ｓｉ：０．１〜１．５％、
Ｍｎ：１．０〜２．０％、Ｓ：０．０２％以下、Ｐ：
０．０３％以下、Ａｌ：０．０１〜０．１０％、Ｃｒ：
１．５％以下、Ｔｉ：０．０２％以下、Ｎ：０．００５
０％以下、必要に応じて、Ｃａを０．０００２〜０．０
０２０％含有し、残部が鉄および不可避不純物からなり
加工性を有するフェライトと残部マルテンサイトおよび
ベイナイトからなる複合組織を有することを特徴とする
加工性の優れた鋼から電縫鋼管であり、これらの電縫鋼
管を製造する方法としては特定の熱延条件をとることに
より解決しようとするものである。また、上記の鋼を高
周波により電縫溶接し造管するに際し、溶接雰囲気を酸
素濃度１００ｐｐｍ以下の不活性ガス雰囲気にして溶接
する加工性に優れた電縫鋼管の製造方法でもある。SUMMARY OF THE INVENTION The present invention provides, in weight percent,
C: 0.02 to 0.15%, Si: 0.1 to 1.5%,
Mn: 1.0 to 2.0%, S: 0.02% or less, P:
0.03% or less, Al: 0.01 to 0.10%, Cr:
1.5% or less, Ti: 0.02% or less, N: 0.005
0% or less, if necessary, 0.0002 to 0.0
An electric resistance welded steel pipe made of a steel excellent in workability characterized by containing 020%, the balance being iron and unavoidable impurities, and having a composite structure composed of ferrite having workability and the remainder consisting of martensite and bainite. As a method of manufacturing an electric resistance welded steel pipe, an attempt is made to solve the problem by taking specific hot rolling conditions. Further, the present invention is also a method for producing an electric resistance welded steel pipe excellent in workability by welding the above steel to an inert gas atmosphere having an oxygen concentration of 100 ppm or less when performing electric resistance welding at high frequency to form a pipe.
【０００６】[0006]
【発明の実施の形態】以下に、本発明の加工性に優れた
電縫鋼管とその製造方法について詳細に説明する。はじ
めに化学成分の限定理由について説明する。Ｃは、Ｃを
含むマルテンサイト相を生成することが本発明の基本と
なっており０．０２％以上必要である。しかし、Ｃが
０．１５％を越えると電縫溶接部の最高硬さが母材と比
較して高くなりすぎハイドロフォ−ムのような厳しい加
工には好ましくない。したがって、Ｃの上限を０．１５
％とした。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an electric resistance welded steel pipe excellent in workability and a method for manufacturing the same according to the present invention will be described in detail. First, the reasons for limiting the chemical components will be described. C forms the basis of the present invention to form a martensitic phase containing C, and requires 0.02% or more. However, if C exceeds 0.15%, the maximum hardness of the electric resistance welded portion becomes too high as compared with the base metal, which is not preferable for severe processing such as hydroforming. Therefore, the upper limit of C is 0.15
%.
【０００７】Ｓｉは脱酸剤として用いる場合には０．１
％以下でよいがフェライトの延性をそれほど損なわずに
フェライトを強化することからＳｉの下限を０．１％と
した。しかし、Ｓｉが１．５％を越えると延性の劣化が
大きくなる。したがって、Ｓｉの上限を１．５％とし
た。When Si is used as a deoxidizer, 0.1
% Or less, but since the ferrite is strengthened without significantly impairing the ductility of the ferrite, the lower limit of Si is set to 0.1%. However, when the content of Si exceeds 1.5%, ductility deteriorates greatly. Therefore, the upper limit of Si is set to 1.5%.
【０００８】Ｍｎはオ−ステナイトの安定性を高めかつ
オ−ステナイトの焼き入れ性を高めるが、その必要量は
冷却速度により変化する。本発明における冷却速度でオ
−ステナイトの安定を高め安定してマルテンサイトを得
るためのＭｎは１．０％以上必要である。しかし、Ｍｎ
が２．０％を越えると電縫溶接部での焼き入れ性が高く
なり硬さが母材と比較して高くなりすぎハイドロフォ−
ムのような厳しい加工には好ましくない。したがって、
Ｍｎの上限を２．０％とした。Mn enhances the stability of austenite and the hardenability of austenite, but the required amount varies depending on the cooling rate. In the present invention, Mn is required to be 1.0% or more to increase the stability of austenite at a cooling rate and stably obtain martensite. However, Mn
Exceeds 2.0%, the hardenability in the electric resistance welded portion increases, and the hardness becomes too high as compared with the base metal.
It is not preferable for severe processing such as rubber. Therefore,
The upper limit of Mn was set to 2.0%.
【０００９】ＳはＭｎＳを形成し、靱性およびプレス加
工性を低下する元素である。特に高強度とした場合、靱
性およびプレス加工性の劣化の影響が強く現れやすい。
そのため可能なかぎり低くする必要がある。そのためＳ
は０．０２％以下にする。Ｐは鋼の強化のために有効で
あるが、０．０３％を越えて過多に添加すれば電縫溶接
性を阻害する。S is an element that forms MnS and reduces toughness and press workability. In particular, when the strength is high, the influence of deterioration in toughness and press workability is likely to be strong.
Therefore, it must be as low as possible. So S
Is set to 0.02% or less. P is effective for strengthening steel, but if added excessively exceeding 0.03%, the resistance to electric resistance welding is impaired.
【００１０】Ａｌは脱酸剤として用いる場合には０．０
１％以下ではその効果がないことからＡｌの下限を０．
０１％とした。しかし、Ａｌが０．１％を越えるとアル
ミナ系介在物が増し加工性が劣化する。したがって、Ａ
ｌの上限を０．１％とした。Ｃｒは焼き入れ性を高めマ
ルテンサイトの生成を容易にする元素であり、経済性の
観点からその上限を１．５％とした。When Al is used as a deoxidizing agent, Al
At 1% or less, there is no effect, so the lower limit of Al is set to 0.1%.
01%. However, when the content of Al exceeds 0.1%, the amount of alumina-based inclusions increases and the workability deteriorates. Therefore, A
The upper limit of 1 was set to 0.1%. Cr is an element that enhances the hardenability and facilitates the formation of martensite, and its upper limit is set to 1.5% from the viewpoint of economy.
【００１１】Ｔｉは鋼中の固溶Ｎを固定し時効による伸
びの劣化を防ぐためには有効な元素であることからその
上限を０．０２％とした。Ｃａを介在物の形態を調整
し、冷間加工性を向上するのに有効であるが、多すぎる
と鋼中の介在物が増し逆に冷間加工性を劣化させること
からＣａは０．０００２〜０．００２０％とした。Since Ti is an effective element for fixing solid solution N in steel and preventing deterioration of elongation due to aging, its upper limit is made 0.02%. Ca is effective in adjusting the form of inclusions to improve cold workability, but too much Ca increases inclusions in the steel and conversely deteriorates cold workability. -0.0020%.
【００１２】次に、鋼板の熱延条件の限定理由について
説明する。最初に冷延材の鋼板の熱延条件および冷延後
の連続焼鈍条件の限定理由について説明する。熱延材の
熱延条件において、仕上温度をＡｒ3 変態点温度−５０
℃〜Ａｒ3 変態点温度＋５０℃の温度範囲にした理由
は、このような低温の圧延によりフェライトの析出核を
増加し、続く６５０℃までの前段冷却により５０％以上
のポリゴナル・フェライトとＣやその他の焼き入れ性を
増す元素が濃化したオ−ステナイトを生成させるためで
ある。仕上温度がＡｒ3 変態点温度＋５０℃を越えると
フェライト析出核の発生が減少し良好なポリゴナル・フ
ェライトが得られない。逆に、α＋γ二相域の低温域で
圧延を行うとフェライトの加工歪みが十分除去されず延
性が劣化する。その限界がＡｒ3 変態点温度−５０℃で
ある。Ｃ等が濃化した安定なオ−ステナイトを前段冷却
中に得るにはフェライトの析出の進行中にも圧延を加え
た方が好ましく、この意味から仕上温度はＡｒ3 変態点
温度以下の方が好ましい。Next, the reasons for limiting the hot rolling conditions of the steel sheet will be described. First, the reasons for limiting the hot rolling conditions of the cold rolled steel sheet and the continuous annealing conditions after cold rolling will be described. Under the hot rolling conditions of the hot rolled material, the finishing temperature was set to the Ar 3 transformation point temperature −50.
The reason for setting the temperature range from ℃ to the Ar 3 transformation point temperature + 50 ℃ is that the precipitation nuclei of ferrite are increased by such low-temperature rolling, and 50% or more of polygonal ferrite and C and This is for generating austenite in which other hardening elements are concentrated. If the finishing temperature exceeds the Ar 3 transformation point temperature + 50 ° C., the generation of ferrite precipitation nuclei decreases, and good polygonal ferrite cannot be obtained. Conversely, when rolling is performed in a low-temperature region of the α + γ two-phase region, work distortion of ferrite is not sufficiently removed, and ductility is deteriorated. The limit is the Ar 3 transformation point temperature −50 ° C. In order to obtain stable austenite enriched in C and the like during the pre-stage cooling, it is preferable to add rolling during the progress of ferrite precipitation. In this sense, the finishing temperature is preferably lower than the Ar 3 transformation point temperature. preferable.
【００１３】次に仕上温度から６５０℃の温度範囲の前
段での平均冷却速度１〜５０℃／ｓの意味するところで
あるが、その終了温度６５０℃はフェライトの析出終了
温度でかつ熱延の冷却過程ではまだパ−ライトが生成し
ない温度である。前段冷却は低温圧延との組み合わせで
ポリゴナル・フェライトの析出を促進し、残ったオ−ス
テナイト中のＣやＭｎ等の濃化を計り安定化する機能を
有する。そのためには冷却速度は遅い方が良く少なくと
も平均冷却速度５０℃／ｓ以下でないといけない。しか
し、あまり遅すぎると生産性が問題となり既存の設備で
は実質上実現不可能のため平均冷却速度を１℃／ｓ以上
とした。Next, the average cooling rate in the former stage of the temperature range from the finishing temperature to 650 ° C. means 1 to 50 ° C./s. The terminating temperature of 650 ° C. is the ferrite precipitation terminating temperature and the cooling of hot rolling. It is a temperature at which no pearlite is formed during the process. The pre-cooling has the function of promoting the precipitation of polygonal ferrite in combination with low-temperature rolling, and measuring and stabilizing the concentration of C and Mn in the remaining austenite. For that purpose, the cooling rate should be slower and the average cooling rate should be at least 50 ° C./s or less. However, if it is too slow, productivity becomes a problem, and it is practically impossible to realize it with existing equipment. Therefore, the average cooling rate was set to 1 ° C./s or more.
【００１４】次に６５０℃から捲取温度の温度範囲の後
段での平均冷却速度１０〜１００℃／ｓの意味するとこ
ろであるが、成分濃化したオ−ステナイトからパ−ライ
トの生成を抑え２５０℃以下という低い捲取温度との組
み合わせでマルテンサイト変態を起こす機能を有する。
そのため、後段の平均冷却速度は１０℃／ｓ以上とする
必要がる。ところが冷却速度があまり早すぎるとフェラ
イト中に固溶Ｃが残存しフェライトの延性を劣化させ
る。従って、平均冷却速度の上限を１００℃／ｓとしな
ければならない。Next, the average cooling rate in the latter stage of the temperature range from 650 ° C. to the winding temperature means 10 to 100 ° C./s. It has a function of causing martensitic transformation in combination with a low winding temperature of not more than ° C.
Therefore, the average cooling rate in the subsequent stage needs to be 10 ° C./s or more. However, if the cooling rate is too fast, solid solution C remains in the ferrite and the ductility of the ferrite deteriorates. Therefore, the upper limit of the average cooling rate must be 100 ° C./s.
【００１５】捲取温度は２５０℃以下でないとパ−ライ
ト変態等をおこし所定の特性が得られない。さらに前段
での平均冷却速度は後段での平均冷却速度よりも小さく
する必要がある。この理由は、連続冷却変態図でフェラ
イトおよびパ−ライトの析出ノ−ズが圧延温度、前段後
段冷却速度により複雑に変化し、条件を満たさない場合
パ−ライトが生じるためと推察される。If the winding temperature is not lower than 250 ° C., pearlite transformation or the like occurs, and the predetermined characteristics cannot be obtained. Further, the average cooling rate in the first stage needs to be lower than the average cooling rate in the second stage. It is presumed that the reason for this is that in the continuous cooling transformation diagram, the precipitation noise of ferrite and pearlite varies in a complicated manner depending on the rolling temperature and the pre-stage and post-stage cooling rates, and pearlite is generated when the conditions are not satisfied.
【００１６】次に電縫鋼管の造管工程について説明す
る。上記に説明した鋼帯を高周波にて電縫溶接し素管を
形成する。しかし、上記に説明した鋼板をＳｉおよびＭ
ｎの添加量が高く、電縫溶接面の加熱溶融時に生成され
たＦｅＯ系の酸化物が鋼中のＳｉ、Ｍｎなどにより還元
されＳｉＯ2 、ＭｎＯなどの反応生成物が生成される。
これらの反応生成物が電縫溶接部に微少な粒状酸化物と
して残存する。このような溶接欠陥を防ぐためには高周
波電縫溶接での溶接雰囲気を不活性ガスによりシ−ル
し、酸素濃度１００ｐｐｍ以下にすることが必須とな
る。このように上記に説明した鋼を電縫鋼管として造管
する場合はシ−ル溶接することで電縫溶接部の優れた電
縫鋼管の製造が可能となる。本発明のように特定の成分
系と熱延、連続焼鈍条件およびシ−ル溶接のような特殊
な電縫鋼管の製造法により高度で複雑な成形にも十分耐
える加工性に優れた電縫鋼管が得られる。Next, a description will be given of a process for forming an ERW steel pipe. The steel strip described above is subjected to electric resistance welding at a high frequency to form a raw tube. However, the steel plates described above are not compatible with Si and M
The addition amount of n is high, and the FeO-based oxide generated during the heating and melting of the electric resistance welded surface is reduced by Si, Mn and the like in the steel, and reaction products such as SiO 2 and MnO are generated.
These reaction products remain as fine particulate oxides in the ERW weld. In order to prevent such welding defects, it is necessary to seal the welding atmosphere in the high-frequency electric resistance welding with an inert gas to reduce the oxygen concentration to 100 ppm or less. As described above, in the case where the steel described above is formed as an ERW steel pipe, it is possible to manufacture an ERW steel pipe having an excellent ERW weld by performing seal welding. ERW steel pipe with excellent workability that can withstand advanced and complicated forming by using a specific component system and a special ERW steel pipe manufacturing method such as hot rolling, continuous annealing conditions and seal welding as in the present invention. Is obtained.
【００１７】[0017]
【実施例】表１に本発明鋼および比較鋼での化学成分を
示す。表２に熱延材の熱延条件を示す。表３に本発明に
より製造された熱延材の電縫鋼管および比較で製造され
た電縫鋼管の管状での機械的特性を示す。表３から明ら
かのように、本発明により製造された電縫鋼管は、Ｅ
Ｌ、均一伸びが非常に高く、電縫溶接部での溶接欠陥も
ない。一方、従来法で製造された電縫鋼管は、本発明に
より製造された電縫鋼管と比較してＥＬ、均一伸びが低
く、電縫溶接部での溶接欠陥が認められるEXAMPLES Table 1 shows the chemical composition of the steel of the present invention and the comparative steel. Table 2 shows the hot rolling conditions of the hot rolled material. Table 3 shows the mechanical properties of the ERW steel pipe of the hot rolled material manufactured according to the present invention and the ERW steel pipe manufactured in comparison. As is apparent from Table 3, the ERW steel pipe manufactured according to the present invention has
L, uniform elongation is very high, and there is no welding defect in the ERW weld. On the other hand, the ERW steel pipe manufactured by the conventional method has lower EL and uniform elongation than the ERW steel pipe manufactured according to the present invention, and welding defects at the ERW weld are observed.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【表２】 [Table 2]
【００２０】[0020]
【表３】 [Table 3]
【００２１】[0021]
【発明の効果】以上述べたように、本発明法により製造
された熱延材の電縫鋼管は加工性を有するフェライトと
残部マルテンサイトおよびベイナイトからなる複合組織
を有することを特徴とする加工性に優れた電縫鋼管であ
る。今後、ハイドロフォ−ムのような複雑な加工に耐え
得る高い延性を有する電縫鋼管の要求がますます増え
る。従って、本発明により製造された電縫鋼管の効果は
極めて大きいものである。As described above, the ERW steel pipe of the hot-rolled material manufactured by the method of the present invention has a workability characterized by having a composite structure of ferrite having workability, the remaining martensite and bainite. ERW steel pipe with excellent resistance. In the future, there will be an increasing demand for ERW pipes having high ductility that can withstand complicated processing such as hydroforming. Therefore, the effect of the electric resistance welded steel pipe manufactured according to the present invention is extremely large.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 佐久間 康治 千葉県君津市君津１番地 新日本製鐵株式 会社君津製鐵所内 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Koji Sakuma 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation Kimitsu Works
Claims (2)
有し、残部が鉄および不可避不純物からなり加工性を有
するフェライトと残部マルテンサイトおよびベイナイト
からなる複合組織を有することを特徴とする加工性に優
れた電縫鋼管。C .: 0.02 to 0.15%, Si: 0.1 to 1.5%, Mn: 1.0 to 2.0%, S: 0.02% or less by weight% P: 0.03% or less; Al: 0.01 to 0.10%; Cr: 1.5% or less; Ti: 0.01% or less; N: 0.0050% or less; An electric resistance welded steel pipe excellent in workability, containing 0.0002 to 0.0020%, the balance being iron and unavoidable impurities, and having a composite structure consisting of ferrite having workability and the remaining martensite and bainite.
有し、残部が鉄および不可避不純物からなり加工性を有
するフェライトと残部マルテンサイトおよびベイナイト
からなる複合組織を有する鋼を熱延するに際して、仕上
温度をＡｒ3 変態点温度−５０℃〜Ａｒ3 変態点温度＋
５０℃とし、２５０℃以下の温度域で捲取り、その際仕
上温度から６５０℃の温度範囲の前段と６５０℃から捲
取温度の温度範囲の後段に分け前段での平均冷却速度を
１〜５０℃／ｓ、後段での平均冷却速度を１０〜１００
℃／ｓで、かつ前段の平均冷却速度が後段の平均冷却速
度よりも小さくした鋼板を高周波により電縫溶接し造管
するに際し、溶接雰囲気を酸素濃度１００ｐｐｍ以下の
不活性ガス雰囲気にし溶接することを特徴とする加工性
に優れた電縫鋼管の製造方法。2. In% by weight, C: 0.02 to 0.15%, Si: 0.1 to 1.5%, Mn: 1.0 to 2.0%, S: 0.02% or less, P: 0.03% or less; Al: 0.01 to 0.10%; Cr: 1.5% or less; Ti: 0.01% or less; N: 0.0050% or less; When hot rolling a steel containing 0.0002 to 0.0020%, the balance being iron and unavoidable impurities and having a workability of ferrite and the remainder consisting of martensite and bainite, the finishing temperature is changed to the Ar 3 transformation point. Temperature -50 ° C to Ar 3 transformation point temperature
Winding is performed at a temperature range of 50 ° C. or less and 250 ° C. or less. At this time, the average cooling rate in the former stage is divided into a former stage of a temperature range of 650 ° C. from the finishing temperature and a latter stage of a temperature range of 650 ° C. to 1-50. ° C / s, the average cooling rate in the latter stage is 10 to 100
When welding steel plates at ℃ / s and the average cooling rate of the former stage is smaller than the average cooling speed of the latter stage by high frequency welding, the welding atmosphere should be an inert gas atmosphere with an oxygen concentration of 100 ppm or less. A method for producing an electric resistance welded steel pipe excellent in workability characterized by the following.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08317198A JP3779811B2 (en) | 1998-03-30 | 1998-03-30 | ERW steel pipe with excellent workability and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08317198A JP3779811B2 (en) | 1998-03-30 | 1998-03-30 | ERW steel pipe with excellent workability and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11279697A true JPH11279697A (en) | 1999-10-12 |
| JP3779811B2 JP3779811B2 (en) | 2006-05-31 |
Family
ID=13794841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP08317198A Expired - Fee Related JP3779811B2 (en) | 1998-03-30 | 1998-03-30 | ERW steel pipe with excellent workability and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3779811B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1231289A1 (en) * | 2000-06-07 | 2002-08-14 | Nippon Steel Corporation | Steel pipe having high formability and method for producing the same |
| EP1264910A1 (en) * | 2000-02-28 | 2002-12-11 | Nippon Steel Corporation | Steel pipe having excellent formability and method for production thereof |
| JP2006144109A (en) * | 2004-11-24 | 2006-06-08 | Jfe Steel Kk | Electric resistance welded tube having excellent crack resistance in weld zone and its production method |
| CN115874112A (en) * | 2022-11-02 | 2023-03-31 | 包头钢铁（集团）有限责任公司 | Method for manufacturing 1300MPa cold-rolled martensitic steel |
-
1998
- 1998-03-30 JP JP08317198A patent/JP3779811B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1264910A1 (en) * | 2000-02-28 | 2002-12-11 | Nippon Steel Corporation | Steel pipe having excellent formability and method for production thereof |
| EP1264910A4 (en) * | 2000-02-28 | 2006-01-25 | Nippon Steel Corp | Steel pipe having excellent formability and method for production thereof |
| EP1231289A1 (en) * | 2000-06-07 | 2002-08-14 | Nippon Steel Corporation | Steel pipe having high formability and method for producing the same |
| EP1231289A4 (en) * | 2000-06-07 | 2003-06-25 | Nippon Steel Corp | Steel pipe having high formability and method for producing the same |
| EP1462536A1 (en) * | 2000-06-07 | 2004-09-29 | Nippon Steel Corporation | Steel pipe excellent in formability and method of producing the same |
| JP2006144109A (en) * | 2004-11-24 | 2006-06-08 | Jfe Steel Kk | Electric resistance welded tube having excellent crack resistance in weld zone and its production method |
| CN115874112A (en) * | 2022-11-02 | 2023-03-31 | 包头钢铁（集团）有限责任公司 | Method for manufacturing 1300MPa cold-rolled martensitic steel |
| CN115874112B (en) * | 2022-11-02 | 2024-04-30 | 包头钢铁（集团）有限责任公司 | Manufacturing method of 1300 megapascal cold-rolled martensitic steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3779811B2 (en) | 2006-05-31 |
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