JPH05247534A - Manufacture of cr-series ultra high tensile strength resistance welded steel tube excellent in ductility - Google Patents
Manufacture of cr-series ultra high tensile strength resistance welded steel tube excellent in ductilityInfo
- Publication number
- JPH05247534A JPH05247534A JP4681492A JP4681492A JPH05247534A JP H05247534 A JPH05247534 A JP H05247534A JP 4681492 A JP4681492 A JP 4681492A JP 4681492 A JP4681492 A JP 4681492A JP H05247534 A JPH05247534 A JP H05247534A
- Authority
- JP
- Japan
- Prior art keywords
- pipe
- resistance welded
- welded steel
- ductility
- electric resistance
- 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.)
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Abstract
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
る延性の優れたCr系超高張力電縫鋼管を経済的に製造
する方法に関する。BACKGROUND OF THE INVENTION The present invention relates to an ultra-high-strength electric resistance welded steel pipe used for structural members of automobiles, etc., in particular, a tensile strength for door reinforcement of 150 kgf / mm 2 or more and an elongation of 10% or more, which is excellent in ductility. The present invention also relates to a method for economically producing a Cr-based ultra-high-strength electric resistance welded steel pipe.
【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 を超える超高張力電縫鋼管が採
用されつつある。2. Description of the Related Art Regarding structural members such as automobiles, thorough weight reduction is being considered for improving fuel efficiency and environmental measures. As one measure to achieve both safety and safety, some members have a weight of 150 kgf / mm. More than 2 ultra-high tensile ERW steel pipes 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。As a steel pipe material for reinforcing automobile doors, a method of tempering after electric resistance welding, that is, quenching or quenching and tempering, as described in JP-A-3-122219, etc. A method of normalizing a predetermined low alloy steel such as 3-140441 is common.
【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、ピーム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。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
There are two types as described in the prior art section.
First, in the method described in Japanese Patent Application Laid-Open No. 3-122219, special heat treatment equipment for treating each beam is required, and special attention is required to secure dimensions and shapes, and productivity is improved. Is low, and the cost is extremely high in terms of capital investment and productivity. Further, it is unsuitable as a method for manufacturing a square steel pipe or a deformed steel pipe, which is attracting attention as a structural member having higher rigidity, in terms of ensuring 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Cr系超
高張力電縫鋼管の製造方法を提供することを目的にする
ものである。Next, the method of normalizing a predetermined low alloy steel such as Japanese Patent Laid-Open No. 3-140441 can solve the above-mentioned problems of the quenching type, but depending on the component, the material cost becomes high and the ductility deteriorates. There is a case. JP-A-3-14044
In the case of 1, Mn exceeds 3%, production in a converter is practically impossible, and expensive components such as Ni are contained. Moreover, the manufacturing method and elongation of the steel pipe are not disclosed. The present invention is a normalizing type, more economical than conventional methods, easy to manufacture, and has a tensile strength of 150 kgf.
It is an object of the present invention to provide a method for producing an excellent Cr-based ultrahigh-strength electric resistance welded steel pipe having a ductility of 10 mm / mm 2 or more and a ductility of 10% or more.
【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 subject matter 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:
0.0005〜0.006%、Al:0.01〜0.0
8%、B:0.0010〜0.0030%、N:0.0
02〜0.005%、Cr:0.5〜3.0%に、T
i: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
素よりなる電縫鋼管において、造管後、熱処理として焼
準を行なうことを特徴とする延性の優れたCr系超高張
力電縫鋼管の製造方法。(1) Component composition by weight C: 0.15
0.40%, Si: 0.05 to 0.50%, Mn: 2.
0-3.0%, P: 0.005-0.020%, S:
0.0005-0.006%, Al: 0.01-0.0
8%, B: 0.0010 to 0.0030%, N: 0.0
02-0.005%, Cr: 0.5-3.0%, T
i: 0.01 to 0.20%, Nb: 0.01 to 0.20
% Of 1% or more of the balance Fe and unavoidable elements in the electric resistance welded steel pipe, which is characterized by performing normalization as heat treatment after pipe forming Production method.
【0008】(2) 前記(1)項の成分組成よりなる
電縫鋼管において、造管後、熱処理として焼鈍または焼
準を行ない、さらに冷間絞り加工を付加し丸管または角
管・異形管にし、その後焼準の熱処理を行なうことを特
徴とする延性の優れたCr系超高張力電縫鋼管の製造方
法。(2) In the electric resistance welded steel pipe having the composition of the above item (1), after pipe forming, annealing or normalizing is performed as a heat treatment, and further cold drawing is added to the round pipe or square pipe / deformed pipe. The method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, which is characterized by performing normalizing heat treatment.
【0009】(3) 前記(1)項の成分組成よりなる
電縫鋼管において、造管後、熱処理として焼準を行な
い、さらに冷間絞り加工を付加し丸管または角管・異形
管にし、その後焼鈍の熱処理を行なうことを特徴とする
延性の優れたCr系超高張力電縫鋼管の製造方法。(3) In the electric resistance welded steel pipe having the composition of the above item (1), after pipe forming, normalizing is performed as heat treatment, and cold drawing is further applied to form a round pipe, a square pipe or a deformed pipe, A method for manufacturing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, which is characterized by performing annealing heat treatment thereafter.
【0010】(4) 前記(1)項の成分組成よりなる
電縫鋼管において、管用鋼材の熱間板厚圧延時に950
℃以下Ar3 変態点以上で仕上圧延を終了し、引続き6
00℃以上にて巻取り、造管後、熱処理として焼準する
ことを特徴とする延性の優れたCr系超高張力電縫鋼管
の製造方法。(4) In the electric resistance welded steel pipe having the composition of the above item (1), 950 is applied during hot plate thickness rolling of the pipe steel material.
Finishing rolling was completed at ℃ or below Ar 3 transformation point and above, and continued 6
A method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, which comprises winding at 00 ° C. or higher, pipe-making, and normalizing as heat treatment.
【0011】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1〜4に共通の
成分について限定理由を説明する。The present invention will be described in detail below. First, the reasons for limiting the components common to claims 1 to 4 among the components of the steel sheet used in the present invention will be described.
【0012】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。If the C content is small, the ductility is good and the workability is excellent, but the required strength cannot be obtained, so the lower limit was made 0.15%. On the other hand, if it exceeds 0.40%, cold workability such as formability at the time of pipe making and toughness tend to be deteriorated, and the heat-affected zone is hardened during pipe making welding of the electric resistance welded steel pipe, resulting in cutting or the like. The upper limit was set to 0.40% because it causes problems.
【0013】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、0.5%
を上限とした。In the case of killed steel, it is difficult to control the Si content to less than 0.05% in terms of steelmaking technology, and if it exceeds 0.50%, the electric resistance weldability and toughness deteriorate, so 0.5% is required.
Was set as the upper limit.
【0014】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 is required to be at least 2.0% or more in order to increase strength and secure elongation. If it exceeds 3.0%, melting in a converter becomes extremely difficult, so the lower limit is 2.0% and the upper limit is 3.0%.
And
【0015】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
に溶接割を発生しやすいため、下限を0.005%、上
限を0.020%とした。P is an element that is inevitably mixed during steelmaking, but it is difficult to make P less than 0.005% because of steelmaking technology.
If it exceeds 0.020%, weld cracking is likely to occur particularly during electric resistance welding of an ultra-high strength steel pipe, so the lower limit was made 0.005% and the upper limit was made 0.020%.
【0016】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。Similar to P, S is an element that is inevitably mixed during steelmaking, and it is difficult to make it less than 0.0005% in steel making technology. If it exceeds 0.0060%, weld cracking tends to occur during electric resistance welding. , The lower limit is 0.0005% and the upper limit is 0.
It was set to 0060%. In order to further suppress cracking during electric resistance welding with S, Ca, which is an element that controls the morphology of MnS, may be added.
【0017】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 to control Al to less than 0.01% in terms of steelmaking technology, and when it exceeds 0.08%, cracks in cast slabs, internal defects due to formation of large oxide inclusions, etc. Therefore, the lower limit is 0.01% and the upper limit is 0.08%.
【0018】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 the ferrite transformation in the cooling process to obtain a high-strength transformation structure, but also in the composition of the steel of the present invention, if it is less than 0.0010%, the strength becomes insufficient and 0.0030%. Bor is exceeded
on Constituent is generated and ductility is remarkably reduced, so the lower limit is 0.0010% and the upper limit is 0.0
It was set to 030%.
【0019】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 unavoidably mixed during steelmaking, but it is difficult to keep it less than 0.002% in steel making technology, and if it exceeds 0.005%, the strength increasing effect of Ti and B is impaired and the strength is increased. The lower limit is 0.002 to cause a shortage.
%, And the upper limit was 0.005%.
【0020】Crは比較的経済的な成分であり、フェラ
イト変態を抑制し、造管後の熱処理により一部マルテン
サイトを含むベイナイト組織を得て、強度を上げるのに
有効であるため、0.5%以上を含有させる。この場
合、3.0%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3.0%とした。Cr is a relatively economical component and is effective in suppressing ferrite transformation and obtaining a bainite structure containing a part of martensite by heat treatment after pipe forming and increasing the strength. 5% or more is contained. In this case, even if added over 3.0%, there is little improvement in effect,
The upper limit was set to 3.0% because it deteriorates the ductility.
【0021】Ti、Nbについては、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、Nbは同様の効果であ
るので1種以上含有すれば目的は達成できる。[0021] Ti and Nb are elements that have the effect of refining because they expand the unrecrystallized γ region in hot rolling, strengthen precipitation, and increase the strength of steel materials. Since it is effective for manufacturing ERW steel pipe, 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 set to 0.01% and the upper limits are set to 0.20%, respectively. Since Ti and Nb have the same effect, the purpose can be achieved if at least one of them is contained.
【0022】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. The manufacturing process of the present invention is shown in FIG. According to the present invention, it is desirable that the finish rolling of the steel having the above components is finished 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 an improvement in toughness is desired and when a low strength steel plate is obtained to facilitate pipe making. Above 950 ° C, there is no rolling in the non-recrystallized region, so the strength and ductility deteriorate, and
If it is less than 3 transformation points, the strength is increased by the two-phase rolling but the ductility is remarkably reduced. Therefore, by finishing rolling the steel having the above components at a temperature of 950 ° C. or less and at an Ar 3 transformation point or more during hot rolling, and continuously winding the steel under the conditions of the present invention, low strength and ductility that are easy to manufacture in a post process are obtained. It can be an excellent material.
【0023】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。When the coiling temperature is 600 ° C. or higher, the cooling rate in the coil is close to that of the furnace cooling, so that the precipitation of Mo and the like is overaged and the ferrite precipitates, which has relatively low strength and ductility. Can manufacture steel sheets. The steel sheet manufactured in this manner has sufficient ductility for forming an electric resistance welded pipe.
【0024】造管後に熱処理として焼準を行なう。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 +2
0℃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10〜150
℃/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 making, normalization is performed as a heat treatment. These are heated to the Ac 3 point or higher and transformed into austenite and then cooled in the same manner as air-cooling to suppress the formation of ferrite and form a bainite-based structure partially containing martensite to increase the strength. The normalizing temperature is Ac 3 +2 in consideration of temperature variations.
The temperature is 0 ° C or higher, and the upper limit is preferably Ac 3 + 70 ° C or lower in order to keep fine grains and to balance strength and ductility. Also,
Air cooling here has a cooling rate of 10 to 150 up to 300 ° C.
It is in the range of ° C / min. If the heat treatment is performed at an Ac < 3 point, the above effect cannot be obtained, and the desired strength cannot be obtained.
【0025】以上本発明について説明したが、請求項2
記載の方法でもよい。図2は請求項2記載の方法に従っ
た工程を示す。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 present invention has been described above.
The described method may be used. FIG. 2 shows the steps according to the method of claim 2. By adding cold drawing as described above, it is possible to manufacture square steel pipes and deformed steel pipes having excellent bending strength. FIG. 3 shows examples of the shapes of the rectangular and deformed steel pipes. Cold drawing includes a method using die drawing and a method using roll forming. The blank heat treatment is to remove work strain caused by cold working at the time of pipe making, soften the quench-hardened portion of the electric resistance welded portion, and improve cold drawing workability, and softening annealing at 600 ° C. or higher or Normalize. In the final heat treatment after cold drawing, normalization is performed in order to remove cold work strain and improve the balance of strength and ductility. However,
Since strength has already been sufficiently increased when normalizing is performed as the heat treatment for the shell, annealing is performed as the finish heat treatment after cold drawing. In this way, an appropriate strength-ductility balance can be obtained by combining the work hardening amount by cold working and the annealing temperature. Although the annealing temperature depends on the cold working rate, it is effective from 450 ° C or higher.
【0026】[0026]
【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な
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なった
が、要は冷間で絞り加工を行な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。[Example] In Table 1, size φ34.1 × t2.0 mm
The conditions and results for producing the electric resistance welded steel pipe of No. 3 by the conventional method and the method of the present invention are shown. The cold drawn tube here was drawn into a square shape using a die. The conventional method is 150 kgf /
Even if the strength of mm 2 or more is achieved, the elongation cannot reach 10%, but 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-strength electric resistance welded steel pipe having a uniform base material portion / welded portion and an excellent balance of strength and ductility by applying a heat treatment for normalization after pipe forming. Since various dimensions can be easily manufactured by adding cold pipe drawing after heat treatment, small lots can be handled and it is economical.
Further, since it can be processed into an arbitrary cross section, it is possible to manufacture a square tube or the like having excellent bending workability. Further, normalization is performed after cold drawing to increase ductility and improve the strength-ductility balance. Further, if necessary, by appropriately controlling the finish rolling temperature and the winding temperature in the hot plate thickness rolling, it is possible to manufacture a raw material steel plate having low strength and excellent ductility and facilitate pipe making. .. Although cold drawing was performed in this example, the point is that if cold drawing is performed, the strength can be increased by work hardening, so the same effect can be obtained by drawing using roll forming.
【0027】[0027]
【表1】 [Table 1]
【0028】[0028]
【表2】 [Table 2]
【0029】[0029]
【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。EFFECTS OF THE INVENTION According to the present invention, there is no need for quenching, quenching, or tempering after an electric resistance welded pipe, and no special heat treatment equipment for treating each piece is required, 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. Also, compared to the conventional normalizing type, it can be manufactured in a converter,
It is economical because it does not contain expensive alloys such as Ni. Furthermore, the tensile strength is 150 kgf /
Since it becomes possible to manufacture an ultra-high-strength electric resistance welded steel pipe having an excellent strength-elongation balance of mm 2 or more and an elongation of 10% or more, the industrial contribution is extremely large.
【図1】本発明の請求項1記載の方法の製造工程図。FIG. 1 is a manufacturing process diagram of a method according to claim 1 of the present invention.
【図2】請求項2および3記載の方法の製造工程を示す
図。FIG. 2 is a diagram showing manufacturing steps of the method according to claims 2 and 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。3 (a), (b) and (c) are diagrams showing examples of the shapes of the square and deformed steel pipes of the present invention.
Claims (4)
管において、造管後、熱処理として焼準を行なうことを
特徴とする延性の優れたCr系超高張力電縫鋼管の製造
方法。1. Component composition by weight C: 0.15 to 0.40%, Si: 0.05 to 0.50%, Mn: 2.0 to 3.0%, P: 0.005 to 0 0.020%, S: 0.0005 to 0.0060%, Al: 0.01 to 0.08%, B: 0.0010 to 0.0030%, N: 0.002 to 0.005%, Cr: ERW steel pipe consisting of balance Fe and inevitable elements containing 0.5 to 3.0% of Ti: 0.01 to 0.20% and Nb: 0.01 to 0.20% or less. In the method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe excellent in ductility, which is characterized in that normalizing is performed as heat treatment after pipe making.
おいて、造管後、熱処理として焼鈍または焼準を行な
い、さらに冷間絞り加工を付加し丸管または角管・異形
管にし、その後焼準の熱処理を行なうことを特徴とする
延性の優れたCr系超高張力電縫鋼管の製造方法。2. The electric resistance welded steel pipe having the composition of claim 1, after pipe forming, annealing or normalizing is performed as a heat treatment, and further cold drawing is added to form a round pipe, a square pipe or a deformed pipe, and then A method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, characterized by performing normalizing heat treatment.
おいて、造管後、熱処理として焼準を行ない、さらに冷
間絞り加工を付加し丸管または角管・異形管にし、その
後焼鈍の熱処理を行なうことを特徴とする延性の優れた
Cr系超高張力電縫鋼管の製造方法。3. An electric resistance welded steel pipe having the composition as defined in claim 1, wherein after pipe forming, normalizing is performed as heat treatment, and cold drawing is further applied to form a round pipe, a square pipe or a deformed pipe, and then annealing is performed. A method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, which is characterized by heat treatment.
おいて、管用鋼材の熱間板厚圧延時に950℃以下Ar
3 変態点以上で仕上圧延を終了し、引続き600℃以上
にて巻取り、造管後、熱処理として焼準することを特徴
とする延性の優れたCr系超高張力電縫鋼管の製造方
法。4. An electric resistance welded steel pipe having the composition of claim 1, wherein Ar is 950 ° C. or less when hot rolling the pipe steel.
A method for producing a Cr-based ultra-high-strength electric resistance welded steel pipe having excellent ductility, which comprises finishing rolling at 3 or more transformation points, continuously winding at 600 ° C. or higher, pipe forming, and normalizing as heat treatment.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4681492A JPH05247534A (en) | 1992-03-04 | 1992-03-04 | Manufacture of cr-series ultra high tensile strength resistance welded steel tube excellent in ductility |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4681492A JPH05247534A (en) | 1992-03-04 | 1992-03-04 | Manufacture of cr-series ultra high tensile strength resistance welded steel tube excellent in ductility |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH05247534A true JPH05247534A (en) | 1993-09-24 |
Family
ID=12757805
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4681492A Withdrawn JPH05247534A (en) | 1992-03-04 | 1992-03-04 | Manufacture of cr-series ultra high tensile strength resistance welded steel tube excellent in ductility |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH05247534A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100392135C (en) * | 2005-06-30 | 2008-06-04 | 宝山钢铁股份有限公司 | Ultra-high strength strip steel and its production process |
-
1992
- 1992-03-04 JP JP4681492A patent/JPH05247534A/en not_active Withdrawn
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100392135C (en) * | 2005-06-30 | 2008-06-04 | 宝山钢铁股份有限公司 | Ultra-high strength strip steel and its production process |
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