JP2000096187A - High-strength welded steel tube - Google Patents
High-strength welded steel tubeInfo
- Publication number
- JP2000096187A JP2000096187A JP10267838A JP26783898A JP2000096187A JP 2000096187 A JP2000096187 A JP 2000096187A JP 10267838 A JP10267838 A JP 10267838A JP 26783898 A JP26783898 A JP 26783898A JP 2000096187 A JP2000096187 A JP 2000096187A
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- weld metal
- less
- strength
- welding
- toughness
- Prior art date
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- Butt Welding And Welding Of Specific Article (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、石油、天然ガス等
を輸送するためのラインパイプ等に使用される低温靭性
に優れ、製管溶接時に溶接金属に横割れが発生しない高
強度溶接鋼管に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength welded steel pipe excellent in low-temperature toughness used for line pipes for transporting petroleum, natural gas and the like, and which does not cause lateral cracks in a weld metal during pipe welding. .
【０００２】[0002]
【従来の技術】天然ガス、原油等を長距離輸送するパイ
プラインでは操業圧力の上昇に伴って輸送効率が改善さ
れ、天然ガス等の輸送コストが低減されてきている。操
業圧力を高めるためには、パイプの肉厚を増加させる
か、またはパイプ材を高強度化することが必要となる。
パイプの厚肉化は、現地溶接施工能率の低下とパイプの
重量増加による施工効率の低下が生じるという問題点が
ある。このような背景のもとで、ラインパイプ材に対す
る高強度化ニーズが高まっており、現在、米国石油協会
（ＡＰＩ）規格でＸ８０グレード鋼（降伏強さＹＰが５
５１ＭＰａ以上、引張強さＴＳが６２０ＭＰａ以上）が
規格化され実用に供されている。2. Description of the Related Art In pipelines for transporting natural gas, crude oil and the like over long distances, transport efficiency has been improved with an increase in operating pressure, and transport costs of natural gas and the like have been reduced. In order to increase the operating pressure, it is necessary to increase the wall thickness of the pipe or to increase the strength of the pipe material.
Increasing the thickness of the pipe has a problem that the efficiency of on-site welding decreases and the efficiency of the welding decreases due to an increase in the weight of the pipe. Against this background, there is an increasing need for high-strength line pipe materials. Currently, X80 grade steel (yield strength YP of 5
51 MPa or more and a tensile strength TS of 620 MPa or more) are standardized and put to practical use.
【０００３】ラインパイプ材の高強度化に関しては、Ｘ
８０グレード鋼の製造技術を基にＸ１００グレード鋼
（ＹＳ：６８９ＭＰａ以上、ＴＳ：７６０ＭＰａ以上）
程度までが製造可能であることが明らかにされている。
これらの鋼は、微細なベイナイト組織を有する鋼であ
る。In order to increase the strength of line pipe materials, X
X100 grade steel (YS: 689 MPa or more, TS: 760 MPa or more) based on 80 grade steel manufacturing technology
It has been shown that up to a degree can be manufactured.
These steels have a fine bainite structure.
【０００４】特開平８−２６９５４２号公報および特開
平８−１９９２９２号公報には、引張強さＴＳが９５０
ＭＰａ以上の高強度を有する低温靭性に優れた鋼が開示
されている。 これらの鋼は、高強度で母材の低温靭性
に優れ、また現地溶接性に優れているとされている。し
かし、高強度材の溶接においては、強度が高くなればな
るほど溶接金属に横割れが発生しやすいという問題があ
る。[0004] JP-A-8-269542 and JP-A-8-199292 disclose a tensile strength TS of 950.
A steel having high strength of not less than MPa and excellent in low-temperature toughness is disclosed. These steels are said to have high strength, excellent low-temperature toughness of the base material, and excellent on-site weldability. However, in the welding of high-strength materials, there is a problem that the higher the strength is, the more likely lateral cracks occur in the weld metal.
【０００５】また、ラインパイプにはＵＯ鋼管のような
シーム溶接鋼管が使用されるが、製管時のシーム溶接に
よる母材の熱影響部の靭性が問題となる。ＵＯ鋼管では
管の内外面各１層の溶接でシーム溶接がおこなわれるた
め、円周溶接に比べて溶接入熱量が大きくなり溶接熱影
響部での靭性劣化を招きやすいという問題がある。[0005] A seam welded steel pipe such as a UO steel pipe is used for the line pipe, but the toughness of the heat-affected zone of the base metal due to seam welding at the time of pipe making poses a problem. In UO steel pipes, seam welding is performed by welding one layer each of the inner and outer surfaces of the pipe, so that there is a problem that the welding heat input is greater than in circumferential welding and that the toughness is likely to deteriorate in the weld heat affected zone.
【０００６】[0006]
【発明が解決しようとする課題】本発明の課題は、ＴＳ
が８００ＭＰａ以上で溶接熱影響部の靭性に優れ、製管
溶接時に溶接金属に横割れが発生しない高強度溶接鋼管
を提供することにある。The object of the present invention is to provide a TS
It is an object to provide a high-strength welded steel pipe excellent in toughness of a heat affected zone at 800 MPa or more and having no lateral crack in a weld metal during pipe welding.
【０００７】[0007]
【課題を解決するための手段】高強度溶接鋼管に係わる
本発明の要旨は、以下に示す通りである。The gist of the present invention relating to a high strength welded steel pipe is as follows.
【０００８】「重量％で、Ｃ：０．０２〜０．１５％、
Ｓｉ：０．６％以下、Ｍｎ：０．２〜２．５％、Ｐ：
０．０１５％以下、Ｓ：０．００３％以下、Ｎｉ：０．
２〜３．５％、Sol.Ａｌ：０．１％以下、Ｃａ：０．０
００５〜０．００５％ならびにＮｂ：０．０１〜０．１
％、Ｔｉ：０．０１〜０．１％、Ｂ：０．０００５〜
０．００２５％、Ｃｕ：０．０１〜１．５％、Ｃｒ：
０．０１〜１％、Ｍｏ：０．０１〜０．６％およびＶ：
０．０１〜０．１％のうち１種または２種以上を含有
し、下記式で示されるＰｃｍが０．１８％以上で、引
張強さが８００ＭＰａ以上である鋼からなる溶接鋼管で
あって、その溶接金属が、重量％でＣ：０．０１〜０．
１５％Ｓｉ：０．０２〜０．６％、Ｍｎ：０．６〜３
％、Ｎｉ：３％を超え９．５％以下、Ａｌ：０．００４
〜０．０８％、Ｔｉ：０．００３〜０．０３％およびＯ
（酸素）：０．０６％以下を含有し、式で示されるＰ
ｃｍが０．２５％以上で、かつ下記式を満足している
ことを特徴とする高強度溶接鋼管。"% By weight, C: 0.02 to 0.15%,
Si: 0.6% or less, Mn: 0.2 to 2.5%, P:
0.015% or less, S: 0.003% or less, Ni: 0.
2 to 3.5%, Sol. Al: 0.1% or less, Ca: 0.0
005-0.005% and Nb: 0.01-0.1
%, Ti: 0.01-0.1%, B: 0.0005-
0.0025%, Cu: 0.01 to 1.5%, Cr:
0.01-1%, Mo: 0.01-0.6% and V:
A welded steel pipe made of steel containing one or more of 0.01 to 0.1%, having a Pcm represented by the following formula of 0.18% or more, and a tensile strength of 800 MPa or more. And the weld metal is C: 0.01 to 0.1% by weight.
15% Si: 0.02 to 0.6%, Mn: 0.6 to 3
%, Ni: more than 3% and 9.5% or less, Al: 0.004
-0.08%, Ti: 0.003-0.03% and O
(Oxygen): contains not more than 0.06% and contains P
A high-strength welded steel pipe characterized in that cm is 0.25% or more and the following formula is satisfied.
【０００９】 Pcm=C+Si/30+Mn/20+Ni/60+Cu/20+Cr/20+Mo/15+V/15+5B ・・・・・ 0.3≦Al/O≦1.4 ・・・・・ ただし、式および式の元素記号は、各元素の含有量
（単位：重量％）を表す。」 本発明者らは、前記課題を解決するため、化学組成を種
々変えた鋼板を用いサブマージアーク溶接により溶接継
手を作製し、強度および靭性を調査した。Pcm = C + Si / 30 + Mn / 20 + Ni / 60 + Cu / 20 + Cr / 20 + Mo / 15 + V / 15 + 5B ... 0.3 ≦ Al / O ≦ 1.4 ・ ・... However, the formula and the element symbol of the formula represent the content (unit: wt%) of each element. In order to solve the above-mentioned problems, the present inventors made a welded joint by submerged arc welding using steel sheets having various chemical compositions, and investigated the strength and toughness.
【００１０】具体的には種々の組成を有する鋼板、溶接
ワイヤ（以下、単にワイヤと記す）と塩基度の異なるフ
ラックスを用いることによって、溶接金属の金属成分お
よび溶接金属中の酸素量を変化させた。なお、溶接金属
中の酸素は、主にフラックスの組成により調節した。こ
のようにして得られた溶接継手について引張試験および
シャルピー衝の試験をおこなった結果、下記の知見を得
て本発明を完成させた。Specifically, by using steel sheets having various compositions and welding wires (hereinafter simply referred to as wires) and fluxes having different basicities, the metal components of the weld metal and the amount of oxygen in the weld metal are changed. Was. The oxygen in the weld metal was adjusted mainly by the composition of the flux. As a result of performing a tensile test and a Charpy impact test on the thus obtained welded joint, the following findings were obtained, and the present invention was completed.
【００１１】なお、低温靭性はシャルピー衝撃試験によ
り得られた破面遷移温度および上部棚エネルギーにより
評価した。The low-temperature toughness was evaluated based on the fracture surface transition temperature and the upper shelf energy obtained by the Charpy impact test.
【００１２】ａ）溶接鋼管のシーム溶接の熱影響部の靭
性を確保するには、母材（以下鋼管の溶接金属部以外の
構成材を母材と記す）Ｐｃｍを０．１８以上にする必要
がある。Ｐｃｍが０．１８％未満では焼入性の不足によ
り、熱影響部の組織がラス状の上部ベイナイトとなるた
め著しく靭性を損なう。A) In order to ensure the toughness of the heat-affected zone in seam welding of a welded steel pipe, the base material (hereinafter, the constituent material other than the weld metal part of the steel pipe is referred to as the base material) Pcm must be 0.18 or more. There is. If the Pcm is less than 0.18%, the structure of the heat-affected zone becomes lath-like upper bainite due to insufficient hardenability, thereby significantly impairing toughness.
【００１３】ｂ）溶接金属のＰｃｍの増加に伴って引張
強さが上昇する。Ｐｃｍが０．１８％以上になると、引
張強さ（以下、ＴＳと記す）８００ＭＰａ以上になる溶
接金属が散見されるようになる。B) The tensile strength increases as the Pcm of the weld metal increases. When the Pcm is 0.18% or more, a weld metal having a tensile strength (hereinafter, referred to as TS) of 800 MPa or more may be found.
【００１４】ｃ）ＴＳが８００ＭＰａに満たない溶接金
属は、主に微細なアシキュラーフェライトからなる組織
を有している。一方、ＴＳが８００ＭＰａ以上の溶接金
属ではラス内にセメンタイトが析出した下部ベイナイト
組織が認められる。C) The weld metal having a TS of less than 800 MPa has a structure mainly composed of fine acicular ferrite. On the other hand, in a weld metal having a TS of 800 MPa or more, a lower bainite structure in which cementite is precipitated in the lath is observed.
【００１５】ｃ）同一Ｐｃｍを有する溶接金属で比較し
た場合、式に示したＡｌ／Ｏが０．３未満である場合
には溶接金属中に下部ベイナイト組織が認められず所望
の強度を満たすことができない。Ａｌ／Ｏの上昇に伴っ
て組織がアシキュラーフェライトから上部ベイナイトに
変化する場合には、破面遷移温度の著しい上昇（靭性の
劣化）が生じるが、下部ベイナイトに変化する場合には
靭性の劣化はほとんど生じない。C) Compared with a weld metal having the same Pcm, when Al / O shown in the formula is less than 0.3, no lower bainite structure is observed in the weld metal and the desired strength is satisfied. Can not. When the structure changes from acicular ferrite to upper bainite with an increase in Al / O, a remarkable increase in the fracture surface transition temperature (deterioration of toughness) occurs. Hardly occurs.
【００１６】ｅ）上部棚エネルギーは、溶接金属の強度
上昇および酸素量の増加に伴って低下する。E) The upper shelf energy decreases as the strength of the weld metal increases and the oxygen content increases.
【００１７】ｆ）シーム溶接時の外面溶接により再加熱
された内面溶接金属に横割れが発生するが、溶接金属中
のＮｉ量を増加することにより溶接割れ感受性が低減さ
れ、Ｎｉ量が３％を超えると横割れの発生をほぼ防止で
きる。Ｎｉ量を増加させたシーム溶接金属は、耐水素割
れ性が高いことから周溶接時における溶接割れ防止の観
点からも有利である。また、Ｎｉ量の増加は溶接金属の
靭性の安定化の観点からも有利である。F) Lateral cracking occurs in the inner surface weld metal reheated by outer surface welding during seam welding. However, by increasing the amount of Ni in the weld metal, the susceptibility to weld cracking is reduced and the Ni amount is reduced by 3%. If the number exceeds, the occurrence of lateral cracks can be substantially prevented. A seam weld metal with an increased Ni content is advantageous from the viewpoint of preventing weld cracking during girth welding because of its high resistance to hydrogen cracking. An increase in the amount of Ni is also advantageous from the viewpoint of stabilizing the toughness of the weld metal.
【００１８】[0018]
【発明の実施の形態】本発明の溶接鋼管の母材および溶
接金属の化学組成の限定理由について説明する（以下、
％表示は重量％を示す）。BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the chemical composition of the base metal and weld metal of a welded steel pipe according to the present invention will be described (hereinafter, referred to as "weld metal").
Percentage indicates weight%).
【００１９】１.母材の化学組成 Ｃ：０．０２〜０．１５％ Ｃは、母材の強度を確保するために含有させる。その効
果を得るためには０．０２％以上が必要であり、一方Ｃ
含有量が過剰になると炭化物の析出量の増加および炭化
物の粗大化を招き靭性を劣化させる。また、マルテンサ
イトの硬さが上昇するので溶接部（特に周溶接部）の耐
水素割れ性を劣化させる。このため、その上限を０．１
５％とした。好ましくは０．１％以下である。1. Chemical composition of base material C: 0.02 to 0.15% C is contained to secure the strength of the base material. To obtain the effect, 0.02% or more is required.
When the content is excessive, the precipitation amount of carbides increases and the carbides become coarse, thus deteriorating the toughness. Further, since the hardness of martensite increases, the hydrogen cracking resistance of the welded portion (particularly, the girth welded portion) is deteriorated. Therefore, the upper limit is 0.1
5%. Preferably it is 0.1% or less.
【００２０】Ｓｉ：０．６％以下 Ｓｉは、母材の強度を向上させる元素であり、また脱酸
剤として重要な元素である。しかし、過剰に含有させる
と母材の靭性低下の原因となると共に耐割れ感受性の劣
化を生ずることから、その上限を０．６％とした。好ま
しくは０．０５〜０．３％である。Si: 0.6% or less Si is an element that improves the strength of the base material and is an important element as a deoxidizing agent. However, if it is contained excessively, it causes a decrease in the toughness of the base material and also causes a deterioration in crack resistance, so the upper limit is set to 0.6%. Preferably it is 0.05-0.3%.
【００２１】Ｍｎ：０．２〜２．５％ Ｍｎは、Ｓｉと同様に溶接金属の強度を向上させる元素
であり、また脱酸剤として重要な元素である。その効果
を得るために最低０．２％含有させる必要がある。しか
し、過剰に含有させると鋳片の中心偏析を増大させ、鋼
の品質面で問題を生じることから、その上限を２．５％
とした。好ましくは０．７〜１．７％である。Mn: 0.2 to 2.5% Mn is an element that improves the strength of the weld metal, similar to Si, and is also an important element as a deoxidizing agent. In order to obtain the effect, it is necessary to contain at least 0.2%. However, if it is contained excessively, the segregation at the center of the slab increases, and a problem occurs in the quality of steel.
And Preferably it is 0.7 to 1.7%.
【００２２】Ｐ：０．０１５％以下、Ｓ：０．００３％
以下 ＰおよびＳは、ともに鋼に不可避的に含有される不純物
元素である。シーム溶接した場合、母材中のＰ、Ｓが溶
接金属に混入し、溶接金属中のＰ、Ｓ量が増加し、シー
ム溶接金属に横割れを発生させるので母材中のＰ、Ｓ量
を規制する必要がある。溶接金属の横割れ防止には、Ｐ
は０．０１５％以下、Ｓは０．００３％以下にする必要
があり、低いほど好ましい。母材中のＰ、Ｓ含有量が前
記上限値を超えると、シーム溶接時の外面溶接により再
加熱された内面溶接金属の粒界脆化を助長してシーム溶
接金属に横割れを発生させる。P: 0.015% or less, S: 0.003%
Hereinafter, P and S are both impurity elements inevitably contained in steel. When seam welding is performed, P and S in the base metal are mixed into the weld metal, and the amounts of P and S in the weld metal increase, causing lateral cracks in the seam weld metal. Need to regulate. To prevent lateral cracks in the weld metal, use P
Is required to be 0.015% or less, and S is required to be 0.003% or less. When the contents of P and S in the base metal exceed the above upper limits, grain boundary embrittlement of the inner surface weld metal reheated by the outer surface welding at the time of seam welding is promoted and lateral cracks are generated in the seam weld metal.
【００２３】Ｎｉ：０．２〜３．５％ Ｎｉは、鋼の強度、靭性を高めるために含有させる。
０．２％未満ではその効果は得られない。靭性の改善の
見地からは含有量の上限は特に設ける必要はないが、経
済性を考慮して上限を３．５％とした。Ni: 0.2 to 3.5% Ni is contained in order to increase the strength and toughness of the steel.
If it is less than 0.2%, the effect cannot be obtained. Although there is no particular need to set an upper limit for the content from the viewpoint of improvement in toughness, the upper limit is set to 3.5% in consideration of economy.
【００２４】Ｓｏｌ.Ａｌ：０．１％以下 Ａｌは、脱酸剤として添加される。ただし、脱酸はＳ
ｉ、Ｍｎでも可能であるためＡｌは必須元素ではない。
しかし、添加する場合、過剰に含有させると粗大なＡｌ
化合物が生成して母材の靭性を劣化させるため上限を
０．１％とした。Sol. Al: 0.1% or less Al is added as a deoxidizing agent. However, deoxidation is S
Al is not an essential element because i and Mn are also possible.
However, when it is added, if it is contained excessively, coarse Al
The upper limit was set to 0.1% because a compound was formed to deteriorate the toughness of the base material.
【００２５】なお、Ａｌを添加する場合には母材から溶
接金属に混入するＡｌが、溶接金属の強度上昇に寄与す
ることを期待して、予め求めておいた溶接金属中の推定
酸素量にあわせてＡｌ量を調整することが好ましい。When Al is added, it is expected that Al mixed from the base metal into the weld metal will contribute to an increase in the strength of the weld metal. It is preferable to adjust the amount of Al.
【００２６】Ｃａ：０．０００５〜０．００５％ Ｃａは、耐食性を向上させる効果があり、その効果は
０．０００５％以上でえられ、一方、０．００５％を超
えると粗大な介在物を形成して鋼の清浄性を害するの
で、０．０００５〜０．００５％とした。Ca: 0.0005% to 0.005% Ca has an effect of improving corrosion resistance, and the effect is obtained at 0.0005% or more. On the other hand, when it exceeds 0.005%, coarse inclusions are removed. Since it forms and impairs the cleanliness of steel, it was made 0.0005 to 0.005%.
【００２７】Ｎｂ、Ｔｉ、Ｂ、Ｃｕ、Ｃｒ、Ｍｏおよび
Ｖのうち１種または２種以上：母材の強度を高めるため
に、上記元素の１種または２種以上を含有させる。Ｎｂ
およびＴｉは、０．０１％以上で効果を発揮し、０．１
％を超えると焼入れ性が著しく向上するため溶接割れが
発生し易くなるので、Ｎｂ、Ｔｉはそれぞれ０．０１〜
０．１％とした。One or more of Nb, Ti, B, Cu, Cr, Mo and V: One or more of the above elements are contained in order to increase the strength of the base material. Nb
And Ti exhibit an effect at 0.01% or more, and 0.1% or more.
%, The hardenability is remarkably improved, so that welding cracks easily occur.
0.1%.
【００２８】Ｂは、０．０００５％以上で強度向上の効
果があるが、０．００２５％を超えると焼入れ性が著し
く向上するため溶接割が発生し易くなるので、０．００
０５〜０．００２５％とした。また、Ｃｕは、０．０１
で強度強度向上の効果があるが、１．５％を超えると、
効果が飽和するので、０．０１〜１．５％とした。B has an effect of improving strength when it is 0.0005% or more, but when it exceeds 0.0025%, the hardenability is remarkably improved, so that a crack is easily generated.
05 to 0.0025%. Cu is 0.01
Has the effect of improving the strength, but if it exceeds 1.5%,
Since the effect is saturated, the content is set to 0.01 to 1.5%.
【００２９】Ｃｒは、強度および耐食性を改善する効果
があり、０．０１％以上で効果を発揮し、１％を超える
と母材の靭性が劣化するので、０．０１〜１％とした。
Ｍｏは、０．０１％以上で強度向上効果を発揮し、０．
６％を超えると母材の靭性が劣化するので、０．０１〜
０．６％とした。Ｖも０．０１％で強度向上効果を発揮
し０．１％を超えると母材の靭性が劣化するので、０．
０１〜０．１％とした。Cr has an effect of improving strength and corrosion resistance, and exhibits an effect at 0.01% or more, and if it exceeds 1%, the toughness of the base material is deteriorated.
Mo exerts an effect of improving strength when it is 0.01% or more.
If it exceeds 6%, the toughness of the base material deteriorates.
0.6%. If V is 0.01%, the effect of improving the strength is exhibited, and if it exceeds 0.1%, the toughness of the base material is deteriorated.
01-0.1%.
【００３０】Ｐｃｍ：C+Si/30+Mn/20+Ni/60+Cu/20+Cr/2
0+Mo/15+V/15+5B 上記した個々の元素の量を規定するだけでは不十分であ
り、０．１８％≦Ｐｃｍとする必要がある。Ｐｃｍが、
０．１８％未満の場合には、シーム溶接熱影響部にラス
状の上部ベイナイトが多くなるため著しく靭性が低下す
る。Pcm: C + Si / 30 + Mn / 20 + Ni / 60 + Cu / 20 + Cr / 2
0 + Mo / 15 + V / 15 + 5B It is not sufficient to simply define the amounts of the individual elements described above, and it is necessary to satisfy 0.18% ≦ Pcm. Pcm,
When it is less than 0.18%, the lath-like upper bainite increases in the heat-affected zone of the seam welding, so that the toughness is significantly reduced.
【００３１】母材の化学成分を上記の範囲とすることに
より、ＴＳが８００ＭＰａ以上である鋼管が得られる。By setting the chemical composition of the base material within the above range, a steel pipe having a TS of 800 MPa or more can be obtained.
【００３２】２.溶接金属の化学組成 Ｃ：０．０１〜０．１５％ Ｃは、溶接金属の強度を確保するために含有させる。そ
の効果を得るためには０．０１％以上が必要である。一
方、Ｃを過剰に含有させると、炭化物の析出量の増加お
よび炭化物の粗大化を招き靭性を劣化させる。このた
め、その上限を０．１５％とした。2. Chemical composition of weld metal C: 0.01 to 0.15% C is contained to secure the strength of the weld metal. To obtain the effect, 0.01% or more is required. On the other hand, when C is excessively contained, the precipitation amount of carbides is increased and the carbides are coarsened to deteriorate the toughness. Therefore, the upper limit is set to 0.15%.
【００３３】Ｓｉ：０．０２〜０．６％ Ｓｉは、溶接金属の強度を向上させる元素であり、同時
に脱酸剤として重要な元素である。その効果を得るため
に０．０２％以上が必要である。しかし、過剰に含有さ
せると、溶接金属の靭性低下の原因となると共に、耐割
れ感受性の劣化が生ずることから、その上限を０．６％
とした。好ましくは０．０５〜０．３％である。Si: 0.02 to 0.6% Si is an element that improves the strength of the weld metal and is also an important element as a deoxidizing agent. To obtain the effect, 0.02% or more is required. However, if it is contained excessively, it causes a decrease in toughness of the weld metal and a deterioration in cracking resistance occurs.
And Preferably it is 0.05-0.3%.
【００３４】Ｍｎ：０．６〜３％ Ｍｎは、Ｓｉと同様に溶接金属の強度を向上させる元素
であると同時に脱酸剤として重要な元素である。その効
果を得るためには、最低０．３％は含有させる必要があ
る。しかし、過剰に含有させると溶接金属の靭性低下の
原因となると共に耐割れ感受性の劣化が生ずることか
ら、その上限を３．０％とした。好ましくは０．８〜
２．５％である。Mn: 0.6 to 3% Mn is an element that improves the strength of the weld metal like Si, and is also an important element as a deoxidizer. In order to obtain the effect, it is necessary to contain at least 0.3%. However, if it is contained excessively, it causes a decrease in toughness of the weld metal and also causes a deterioration in crack resistance, so the upper limit was made 3.0%. Preferably 0.8 to
2.5%.
【００３５】Ｎｉ：３％を超え９．５％以下 Ｎｉは、本発明において溶接金属の耐割れ性を改善する
ための重要な元素である。また、溶接金属の焼入性を高
め強度を上昇させるとともに靭性を改善する。溶接金属
中のＮｉ含有量が３％を超えると耐溶接割れ性が顕著に
改善される。Ｎｉ量の上限は、耐溶接性の観点からは特
に設ける必要がないが経済的な観点からその上限を９．
５％とした。好ましくは、３〜６％である。Ni: more than 3% and not more than 9.5% Ni is an important element for improving the crack resistance of the weld metal in the present invention. In addition, it increases the hardenability of the weld metal, increases the strength, and improves the toughness. When the Ni content in the weld metal exceeds 3%, the resistance to weld cracking is significantly improved. The upper limit of the amount of Ni does not need to be particularly set from the viewpoint of welding resistance, but is set to 9. from the viewpoint of economy.
5%. Preferably, it is 3 to 6%.
【００３６】Ｎｉ含有量の増加による耐溶接割れ性の改
善理由は、γ→α変態温度が低下するため溶接後の冷却
過程において溶接残留応力が低減することに起因すると
考える。It is considered that the reason for the improvement in the resistance to weld cracking due to the increase in the Ni content is that the welding residual stress is reduced in the cooling process after welding because the γ → α transformation temperature is reduced.
【００３７】Ａｌ：０．００４〜０．０８％ Ａｌは、脱酸剤として重要な元素であり、その効果を得
るには少なくとも０．００４％含有させる必要である。
一方、過剰に含有させると、粗大な介在物の生成原因と
なるためその上限値を０．０８％とした。また、本発明
では溶接金属の組織制御により溶接金属の強度を向上さ
せるのに重要な元素である。その適正範囲は後述するよ
うに酸素量との関係で決定される。なお、溶接金属のＡ
ｌはトータルＡｌとする。Al: 0.004 to 0.08% Al is an important element as a deoxidizing agent, and it is necessary to contain at least 0.004% to obtain its effect.
On the other hand, if it is contained excessively, it causes the formation of coarse inclusions, so the upper limit was made 0.08%. Further, in the present invention, it is an important element for improving the strength of the weld metal by controlling the structure of the weld metal. The appropriate range is determined based on the relationship with the amount of oxygen as described later. In addition, A of the weld metal
l is the total Al.
【００３８】Ｏ：０．０６％以下 Ｏは、不可避的に溶接金属に混入する成分で、酸素量の
増加はシャルピー衝撃試験の上部棚エネルギーを低下さ
せる。このため、酸素量は低いほど好ましく、その許容
できる上限値は０．０６％、好ましくは０．０４％であ
る。下限値については、限定するものでなく、一般的に
おこなわれる溶融溶接（サブマージアーク溶接、ガスメ
タルアーク溶接、レーザー溶接等）での限界はほぼ０．
００５％となるが、低いほど好ましい。O: 0.06% or less O is an inevitable component that is mixed into the weld metal, and an increase in the amount of oxygen lowers the upper shelf energy in the Charpy impact test. Therefore, the lower the oxygen content, the better, and the allowable upper limit is 0.06%, preferably 0.04%. The lower limit is not limited, and the limit in fusion welding generally performed (submerged arc welding, gas metal arc welding, laser welding, etc.) is almost 0.
005%, the lower the better.
【００３９】Ａｌ／Ｏ：０．３〜１．４ 溶接金属中のＡｌ量とＯ量の比（Ａｌ／Ｏ）が０．３未
満である場合には、組織はアシキュラーフェライト主体
の組織となり十分な強度が得られない。Al / O: 0.3 to 1.4 When the ratio of the Al content to the O content in the weld metal (Al / O) is less than 0.3, the structure becomes a structure mainly composed of acicular ferrite. Sufficient strength cannot be obtained.
【００４０】Ａｌ／Ｏが０．６を超えるとアシキュラー
フェライトの析出量の減少が生じると同時に強度の上昇
が生じる。また、１．４を超えるとアシキュラーフェラ
イトの生成が実質的には生じなくなり、Ａｌ／Ｏの上昇
に伴う強度の上昇が緩やかになる。一方、Ａｌ／Ｏの過
剰な上昇はＡｌ酸化物の粗大化を招き靭性に悪影響を及
ぼすため、その上限を１．４とした。なお、好ましくは
下限値を０．５、上限値を１．２とする。When Al / O exceeds 0.6, the precipitation amount of the acicular ferrite decreases, and at the same time, the strength increases. On the other hand, when the ratio exceeds 1.4, generation of acicular ferrite substantially does not occur, and the increase in strength with the increase in Al / O becomes slow. On the other hand, an excessive increase in Al / O causes coarsening of the Al oxide and adversely affects the toughness. Therefore, the upper limit is set to 1.4. Preferably, the lower limit is 0.5 and the upper limit is 1.2.
【００４１】Ｔｉ：０．００３〜０．０３％ Ｔｉは、焼入性を高め高強度を安定して得られる効果を
有する。その効果を得るためには０．００３％以上の含
有が必要である。一方、含有量が過剰になるとＴｉＣの
析出を生じ溶接金属の靭性を著しく劣化させる。このた
め、その上限値を０．０３％とした。Ti: 0.003 to 0.03% Ti has the effect of enhancing hardenability and stably obtaining high strength. In order to obtain the effect, the content needs to be 0.003% or more. On the other hand, when the content is excessive, precipitation of TiC occurs and the toughness of the weld metal is remarkably deteriorated. Therefore, the upper limit is set to 0.03%.
【００４２】以上の元素の他に、溶接金属の強度を向上
させる目的で、Ｎｂ：０．０５％以下、Ｂ：０．００５
％以下、Ｃｕ：１．２％以下、Ｃｒ：１．２％以下、Ｍ
ｏ：１．０％以下、Ｖ：０．０５％以下 のうちの１種
又は２種以上を含有させることもできる。ただし、いず
れの元素の場合も過剰な添加は靭性や耐割れ性を劣化さ
せるため、上限値は前記した通りとするのが好ましい。In addition to the above elements, for the purpose of improving the strength of the weld metal, Nb: 0.05% or less, B: 0.005
% Or less, Cu: 1.2% or less, Cr: 1.2% or less, M
o: 1.0% or less, V: 0.05% or less. However, in the case of any of the elements, an excessive addition degrades toughness and crack resistance, so the upper limit is preferably as described above.
【００４３】上記した個々の元素の量を規定するだけで
は不十分であり、０．２５％≦Ｐｃｍとする必要があ
る。Ｐｃｍが０．２５％より小さいと十分な強度が得ら
れない。Ｐｃｍが０．２５％未満、かつＡｌ／Ｏが１．
４を超えるような領域では下部ベイナイトが生成せず、
上部ベイナイトが生成するため破面遷移温度が著しく劣
化する。It is not sufficient to simply define the amounts of the individual elements described above, and it is necessary to satisfy 0.25% ≦ Pcm. If Pcm is smaller than 0.25%, sufficient strength cannot be obtained. Pcm is less than 0.25% and Al / O is 1.
In the region exceeding 4, lower bainite does not form,
Since the upper bainite is generated, the fracture surface transition temperature is significantly deteriorated.
【００４４】なお、上記した溶接金属中の成分は母材、
溶接ワイヤ、フラックスのいずれから添加してもよく、
最終的に得られた溶接金属の化学組成が上記限定範囲内
にあれば目的とする特性が得られる。また、不可避的不
純物は少ない方が望ましいが、特にＰ：０．０３％以
下、Ｓ：０．０３％以下、Ｎ：０．０１％以下とするの
が好ましい。The above components in the weld metal are the base metal,
It may be added from any of the welding wire and flux,
If the chemical composition of the finally obtained weld metal is within the above-mentioned limited range, desired properties can be obtained. Further, it is desirable that the unavoidable impurities be small, but it is particularly preferable that P: 0.03% or less, S: 0.03% or less, N: 0.01% or less.
【００４５】製管時のシーム溶接や周溶接には、下記の
化学組成の溶接ワイヤを用いるのが好ましい。It is preferable to use a welding wire having the following chemical composition for seam welding and girth welding during pipe production.
【００４６】Ｃ：０．０２〜０．２％、Ｓｉ：０．２５
〜０．９％、Ｍｎ：０．４〜７％、Ａｌ：０．０２〜
０．２％、Ｏ（酸素）：０．０１％以下、Ｔｉ：０．０
１〜０．５％、Ｃｕ：０〜１．２％、Ｎｉ：３〜３０
％、Ｃｒ：５％以下、Ｍｏ：５％以下、Ｖ：０〜０．０
８％およびＮｂ：０〜０．０８％。C: 0.02 to 0.2%, Si: 0.25
0.9%, Mn: 0.4-7%, Al: 0.02-
0.2%, O (oxygen): 0.01% or less, Ti: 0.0
1 to 0.5%, Cu: 0 to 1.2%, Ni: 3 to 30
%, Cr: 5% or less, Mo: 5% or less, V: 0 to 0.0
8% and Nb: 0-0.08%.
【００４７】ワイヤ中のＰ、ＳおよびＮ等の不可避的不
純物のうち、Ｐ、Ｓは溶接金属に移行して溶接金属の靭
性を低下させるので、Ｐは０．００２％以下、Ｓは０．
０２％以下とすることが望ましい。Of the inevitable impurities such as P, S and N in the wire, P and S migrate to the weld metal and reduce the toughness of the weld metal.
Desirably, it is not more than 02%.
【００４８】[0048]
【実施例】１５０ｋｇ容量の真空精錬炉で、表１に示す
化学組成を有し、Ｐｃｍが０．１７〜０．２２％の鋼を
溶製し、鋳造、鍛造後圧延により板厚２５ｍｍの鋼板に
仕上げた。EXAMPLE In a 150 kg capacity vacuum refining furnace, a steel having the chemical composition shown in Table 1 and having a Pcm of 0.17 to 0.22% was melted, cast, forged and then rolled to obtain a steel plate having a thickness of 25 mm. Finished.
【００４９】[0049]
【表１】 [Table 1]
【００５０】鋼板圧延にあたっては、鍛造した鋼塊を１
１５０℃に加熱した後、８００℃で仕上げ圧延をおこな
い直ちに水冷をおこなった。水冷停止温度は、２５０℃
として圧延後５００℃で焼戻処理をおこなった。When rolling the steel sheet, the forged steel ingot is
After heating to 150 ° C., finish rolling was performed at 800 ° C., and immediately water cooling was performed. Water cooling stop temperature is 250 ° C
After the rolling, a tempering treatment was performed at 500 ° C.
【００５１】いずれの鋼も引張強さは、８００ＭＰａを
超えており強度は目標を満たしている。一方、溶接再現
熱サイクル（１３５０℃加熱、５秒保持、冷却速度１０
℃／秒）を与えてシャルピー衝撃試験をおこなった結
果、Ｐｃｍが０．１８％未満の鋼種４および６では他に
比べて著しく低値を示した。Each of the steels has a tensile strength exceeding 800 MPa, and the strength satisfies the target. On the other hand, welding reproduction heat cycle (heating at 1350 ° C, holding for 5 seconds, cooling rate of 10
(° C./sec), and Charpy impact test showed that steel types 4 and 6 having a Pcm of less than 0.18% showed significantly lower values than the others.
【００５２】次ぎに鋼種１の鋼板を母材にして、表２に
示す化学組成のワイヤを用いて製管時のシーム溶接を模
擬した両面１層の溶接をおこなった溶接試験片を作製し
その性能を調査した。Next, using a steel sheet of steel type 1 as a base material, a welding test piece was prepared by performing welding of one layer on both sides simulating seam welding at the time of pipe making using a wire having a chemical composition shown in Table 2. The performance was investigated.
【００５３】[0053]
【表２】 [Table 2]
【００５４】溶接は、４電極（ＤＣ−ＡＣ−ＡＣ−Ａ
Ｃ）のサブマージアーク溶接でおこなった。フラックス
は、市販の高塩基度溶融型フラックスを用い、溶接前に
はフラックスを２５０℃にて１時間の乾燥をおこなっ
た。For welding, four electrodes (DC-AC-AC-A) were used.
C) was performed by submerged arc welding. As the flux, a commercially available high basicity molten flux was used, and the flux was dried at 250 ° C. for 1 hour before welding.
【００５５】用いたフラックスの拡散水素量をＪＩＳグ
リセリン法で測定したところ拡散性水素量は２．５ｃｃ
／１００ｇであった。溶接入熱量は４０ｋＪ／ｃｍとし
た。溶接を実施するにあたっては、試験片（２５ｍｍ×
２００ｍｍ×８００ｍｍ）を５０ｍｍ×４００ｍｍ×１
２００ｍｍの定盤に拘束した。When the amount of diffusible hydrogen of the flux used was measured by the JIS glycerin method, the amount of diffusible hydrogen was 2.5 cc.
/ 100 g. The welding heat input was 40 kJ / cm. When performing welding, test pieces (25 mm x
200 mm x 800 mm) is converted to 50 mm x 400 mm x 1
It was restrained on a 200 mm platen.
【００５６】得られた溶接金属の化学組成を表３に示
す。Table 3 shows the chemical composition of the obtained weld metal.
【００５７】[0057]
【表３】 [Table 3]
【００５８】溶接金属から引張試験片と、ＪＩＳ４号
（１０ｍｍ角、２ｍｍＶノッチ）衝撃試験片を製作し、
溶接金属の強度および破面遷移温度および棚エネルギー
を調べた。その結果を表４に示す。From the weld metal, a tensile test piece and a JIS No. 4 (10 mm square, 2 mm V notch) impact test piece were manufactured.
The strength, fracture surface transition temperature and shelf energy of the weld metal were investigated. Table 4 shows the results.
【００５９】[0059]
【表４】 [Table 4]
【００６０】試験番号３では、Ａｌ／Ｏが本発明で規定
する下限未満であるため、引張強さが７８０ＭＰａとな
り目標を満足しなかった。本発明例の試験番号４、５で
は充分な強度を有するとともに靭性も良好であった。ま
た、試験番号４、５では横割れが観察されなかったのに
対して、試験番号１、２では横割れの発生が認められ
た。試験番号３で横割れが発生していないのは、溶接金
属の引張強さが低く硬さが低下したためと思われる。In Test No. 3, since Al / O was less than the lower limit specified in the present invention, the tensile strength was 780 MPa, which did not satisfy the target. Test Nos. 4 and 5 of the examples of the present invention had sufficient strength and good toughness. Further, in Test Nos. 4 and 5, no lateral crack was observed, whereas in Test Nos. 1 and 2, occurrence of lateral crack was observed. The reason why lateral cracks did not occur in Test No. 3 is probably because the tensile strength of the weld metal was low and the hardness was reduced.
【００６１】以上のように本願発明で規定する条件を満
足する鋼板、溶接金属の組み合わせにより靭性、耐割れ
性に優れた高強度鋼管が得られることが明らかである。As described above, it is apparent that a high strength steel pipe excellent in toughness and crack resistance can be obtained by combining a steel sheet and a weld metal satisfying the conditions specified in the present invention.
【００６２】[0062]
【発明の効果】本発明によれば、８００ＭＰａ以上の引
張強さを有する低温靭性に優れ、溶接時に溶接金属に横
割れが発生しない鋼管を安価に提供することが可能であ
る。本発明の溶接鋼管を用いることにより８００ＭＰａ
以上の引張強さを有するパイプライン、圧力容器等の溶
接構造物の製造が可能となる。According to the present invention, it is possible to inexpensively provide a steel pipe which is excellent in low-temperature toughness having a tensile strength of 800 MPa or more and which does not cause lateral cracks in a weld metal during welding. 800 MPa by using the welded steel pipe of the present invention
Manufacture of welded structures such as pipelines and pressure vessels having the above tensile strength is possible.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 岡口 秀治 大阪府大阪市中央区北浜４丁目５番33号住 友金属工業株式会社内 (72)発明者 藤原 知哉 大阪府大阪市中央区北浜４丁目５番33号住 友金属工業株式会社内 Ｆターム(参考） 4E001 AA03 BB05 CA02 CC03 EA10 QA02 4E081 YQ01 YX02 YX07 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shuji Okaguchi 4-33, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Inside Sumitomo Metal Industries, Ltd. (72) Tomoya Fujiwara 4-chome, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture No. 5-33 F-term in Sumitomo Metal Industries, Ltd. (reference) 4E001 AA03 BB05 CA02 CC03 EA10 QA02 4E081 YQ01 YX02 YX07
Claims (1)
ｉ：０．６％以下、Ｍｎ：０．２〜２．５％、Ｐ：０．
０１５％以下、Ｓ：０．００３％以下、Ｎｉ：０．２〜
３．５％、Sol.Ａｌ：０．１％以下、Ｃａ：０．０００
５〜０．００５％ならびにＮｂ：０．０１〜０．１％、
Ｔｉ：０．０１〜０．１％、Ｂ：０．０００５〜０．０
０２５％、Ｃｕ：０．０１〜１．５％、Ｃｒ：０．０１
〜１％、Ｍｏ：０．０１〜０．６％およびＶ：０．０１
〜０．１％のうち１種または２種以上を含有し、下記式
で示されるＰｃｍが０．１８％以上で、引張強さが８
００ＭＰａ以上である鋼からなる溶接鋼管であって、そ
の溶接金属が、重量％でＣ：０．０１〜０．１５％、Ｓ
ｉ：０．０２〜０．６％、Ｍｎ：０．６〜３％、Ｎｉ：
３％を超え９．５％以下、Ａｌ：０．００４〜０．０８
％、Ｔｉ：０．００３〜０．０３％およびＯ（酸素）：
０．０６％以下を含有し、式で示されるＰｃｍが０．
２５％以上で、かつ下記式を満足していることを特徴
とする高強度溶接鋼管。 Pcm=C+Si/30+Mn/20+Ni/60+Cu/20+Cr/20+Mo/15+V/15+5B ・・・・・ 0.3≦Al/O≦1.4 ・・・・・ ただし、式および式の元素記号は、各元素の含有量
（単位：重量％）を表す。(1) C: 0.02 to 0.15% by weight, S
i: 0.6% or less, Mn: 0.2 to 2.5%, P: 0.
015% or less, S: 0.003% or less, Ni: 0.2 to
3.5%, Sol. Al: 0.1% or less, Ca: 0.000
5 to 0.005% and Nb: 0.01 to 0.1%,
Ti: 0.01-0.1%, B: 0.0005-0.0
025%, Cu: 0.01 to 1.5%, Cr: 0.01
１1%, Mo: 0.01 to 0.6% and V: 0.01
０．１0.1% or more, and Pcm represented by the following formula is 0.18% or more and tensile strength is 8
A welded steel pipe made of steel having a pressure of not less than 00 MPa, wherein the weld metal is C: 0.01 to 0.15% by weight, S:
i: 0.02 to 0.6%, Mn: 0.6 to 3%, Ni:
More than 3% and 9.5% or less, Al: 0.004 to 0.08
%, Ti: 0.003 to 0.03% and O (oxygen):
0.06% or less, and the Pcm represented by the formula is 0.
A high-strength welded steel pipe characterized by not less than 25% and satisfying the following expression. Pcm = C + Si / 30 + Mn / 20 + Ni / 60 + Cu / 20 + Cr / 20 + Mo / 15 + V / 15 + 5B ・ ・ ・ ・ ・ 0.3 ≦ Al / O ≦ 1.4 ・ ・ ・ ・ ・Here, the formulas and the element symbols in the formulas represent the contents (unit:% by weight) of each element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10267838A JP2000096187A (en) | 1998-09-22 | 1998-09-22 | High-strength welded steel tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10267838A JP2000096187A (en) | 1998-09-22 | 1998-09-22 | High-strength welded steel tube |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000096187A true JP2000096187A (en) | 2000-04-04 |
Family
ID=17450331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10267838A Pending JP2000096187A (en) | 1998-09-22 | 1998-09-22 | High-strength welded steel tube |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000096187A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001335879A (en) * | 2000-05-29 | 2001-12-04 | Kobe Steel Ltd | Weld metal |
| JP2008087031A (en) * | 2006-10-02 | 2008-04-17 | Nippon Steel Corp | Welded joint having excellent resistance to generation of brittle fracture |
| CN102114581A (en) * | 2011-04-06 | 2011-07-06 | 钢铁研究总院 | Gas shield welding wire for oil cargo tank of oil tanker |
| JP2013111642A (en) * | 2011-11-30 | 2013-06-10 | Jfe Steel Corp | Test piece and method for welding evaluation test |
| CN105234588A (en) * | 2015-11-20 | 2016-01-13 | 四川大西洋焊接材料股份有限公司 | High-toughness electrogas vertical welding flux-cored wire matched with corrosion-resistant COT steel and preparation method thereof |
| JP2016079474A (en) * | 2014-10-17 | 2016-05-16 | 新日鐵住金株式会社 | Weld joint |
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| JPH02217172A (en) * | 1989-02-17 | 1990-08-29 | Kobe Steel Ltd | Steel welding method |
| JPH08252690A (en) * | 1995-03-14 | 1996-10-01 | Nippon Steel Corp | Weld metal for gas metal arc welding |
| JPH09209079A (en) * | 1996-02-08 | 1997-08-12 | Sumitomo Metal Ind Ltd | Welded steel pipe excellent in corrosion resistance to carbon dioxide gas and toughness in weld zone, pipe, line, and girth welding method for steel pipe |
| JPH1025535A (en) * | 1996-07-11 | 1998-01-27 | Sumitomo Metal Ind Ltd | High tensile strength steel for large heat input welding, and its production |
| JPH1058186A (en) * | 1996-08-20 | 1998-03-03 | Sumitomo Metal Ind Ltd | Welded metal excellent in cold toughness |
| JPH10317097A (en) * | 1997-05-15 | 1998-12-02 | Sumitomo Metal Ind Ltd | High tensile strength steel excellent in weld crack resistance, and its production |
| JPH10324950A (en) * | 1997-03-26 | 1998-12-08 | Sumitomo Metal Ind Ltd | High-strength welded steel structure, and its manufacture |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02217172A (en) * | 1989-02-17 | 1990-08-29 | Kobe Steel Ltd | Steel welding method |
| JPH08252690A (en) * | 1995-03-14 | 1996-10-01 | Nippon Steel Corp | Weld metal for gas metal arc welding |
| JPH09209079A (en) * | 1996-02-08 | 1997-08-12 | Sumitomo Metal Ind Ltd | Welded steel pipe excellent in corrosion resistance to carbon dioxide gas and toughness in weld zone, pipe, line, and girth welding method for steel pipe |
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| JPH10324950A (en) * | 1997-03-26 | 1998-12-08 | Sumitomo Metal Ind Ltd | High-strength welded steel structure, and its manufacture |
| JPH10317097A (en) * | 1997-05-15 | 1998-12-02 | Sumitomo Metal Ind Ltd | High tensile strength steel excellent in weld crack resistance, and its production |
| JPH11267844A (en) * | 1998-03-19 | 1999-10-05 | Sumitomo Metal Ind Ltd | Manufacture of welded steel structure and welded steel structure |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001335879A (en) * | 2000-05-29 | 2001-12-04 | Kobe Steel Ltd | Weld metal |
| JP2008087031A (en) * | 2006-10-02 | 2008-04-17 | Nippon Steel Corp | Welded joint having excellent resistance to generation of brittle fracture |
| CN102114581A (en) * | 2011-04-06 | 2011-07-06 | 钢铁研究总院 | Gas shield welding wire for oil cargo tank of oil tanker |
| JP2013111642A (en) * | 2011-11-30 | 2013-06-10 | Jfe Steel Corp | Test piece and method for welding evaluation test |
| JP2016079474A (en) * | 2014-10-17 | 2016-05-16 | 新日鐵住金株式会社 | Weld joint |
| CN105234588A (en) * | 2015-11-20 | 2016-01-13 | 四川大西洋焊接材料股份有限公司 | High-toughness electrogas vertical welding flux-cored wire matched with corrosion-resistant COT steel and preparation method thereof |
| CN105234588B (en) * | 2015-11-20 | 2018-01-16 | 四川大西洋焊接材料股份有限公司 | Corrosion-resistant matched high tenacity electro-gas (enclosed) welding flux-cored wire of COT steel and preparation method thereof |
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