JP4486529B2 - Electrogas welding joint with excellent toughness - Google Patents
Electrogas welding joint with excellent toughness Download PDFInfo
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本発明は、大型船舶等の溶接構造体における破壊発生の最も高い部位である溶接継手部の耐脆性破壊発生特性を大幅に改善するエレクトロガスアーク溶接方法に関するものである。
具体的には、降伏強度が360Ｎ/ｍｍ2以上、板厚が50ｍｍ以上、80ｍｍ以下の鋼材を、１電極または２電極のうちの少なくとも１電極にフラックス入りワイヤを用いて立向き溶接する１電極または２電極エレクトロガス溶接継ぎ手に関する。
The present invention relates to an electrogas arc welding method that greatly improves the brittle fracture resistance of a welded joint, which is the highest occurrence site of fracture in a welded structure such as a large ship.
Specifically, one electrode for welding upright steel with a yield strength of 360 N / mm 2 or more and a plate thickness of 50 mm or more and 80 mm or less using flux-cored wire to at least one of one electrode or two electrodes Or a two-electrode electrogas welding joint.
大型造船構造物等の溶接構造体において、最も破壊発生の可能性の高い部位は溶接継手部である。この理由は、溶接時に溶接欠陥を生じさせる可能性があり、破壊の起点となる応力集中部が存在する可能性が高いこと、溶接熱影響により鋼材の組織が粗大化し、溶接継手の脆性破壊発生に対する指標として用いられている破壊靱性値：Ｋｃが低下していること、等である。
溶接金属部の破壊靱性を確保するためには簡便のためシャルヒ゜ー衝撃値が規定されている。このシャルヒ゜ー衝撃値（以下靭性）を確保するためには、アーク溶接において十分に焼き入れ性を確保してアシキュラーフェライトを主体とする組織に制御することが一般的に実施されてきた。例えば、非特許文献１に開示されているように、Ｔｉ−Ｂ系の溶接金属を用い、粒界の粗大フェライトをなくし、微細なアシキュラーフェライト組織単相として、溶接金属の靱性を確保してきた。
このときの溶接金属の硬さは、少なくとも２２０以上必要であった。
In a welded structure such as a large shipbuilding structure, a portion having the highest possibility of occurrence of fracture is a welded joint. This is because there is a possibility that a weld defect may occur during welding, and there is a high possibility that there is a stress concentration part that becomes the starting point of fracture, and the steel structure becomes coarse due to the influence of welding heat, causing brittle fracture of welded joints Fracture toughness value used as an index to: Kc is lowered, and the like.
In order to ensure the fracture toughness of the weld metal part, the Charpy impact value is defined for simplicity. In order to ensure this Charpy impact value (hereinafter referred to as toughness), it has been generally practiced to ensure a sufficient hardenability in arc welding and control to a structure mainly composed of acicular ferrite. For example, as disclosed in Non-Patent Document 1, Ti—B based weld metal is used to eliminate coarse ferrite at grain boundaries, and the toughness of the weld metal has been ensured as a single phase of fine acicular ferrite structure. .
At this time, the hardness of the weld metal was required to be at least 220 or more.
しかしながら、エレクトロガスアーク溶接などの大入熱溶接の場合には、その鋼材の熱影響部は大きく軟化するために、溶接金属の硬さがＨＡＺの硬さよりも大幅に硬くなる。その場合には、溶接金属と鋼材が変形せずに、軟化したＨＡＺに歪が集中することと、その変形しようとするＨＡＺを溶接金属と鋼材が拘束するために、図２に示すように、溶接金属の硬さ（Ｈｖ）が２２０を超えると、脆性破壊発生抵抗特性（Ｋｃ）が低下することが分かった。
また、特開平１１−１９７８８４号公報には、ワイヤ中のC,Si,Mn,Ti,Bを特定範囲とすることによって、良好な溶接作業性と優れた溶接金属性能が得られる２電極エレクトロアークガス溶接方法が開示されている。
しかし、この特開平１１−１９７８８４号公報には、本発明の特徴である溶接金属の硬さ（Ｈｖ）と破壊靭性との関係については、検討されていなかった。
Japanese Patent Application Laid-Open No. 11-197884 discloses a two-electrode electroarc in which good welding workability and excellent weld metal performance can be obtained by setting C, Si, Mn, Ti, and B in the wire to a specific range. A gas welding method is disclosed.
However, in JP-A-11-197884, the relationship between weld metal hardness (Hv) and fracture toughness, which is a feature of the present invention, has not been studied.
最近の溶接構造物の大型化に伴い、高強度で、かつ板厚５０ｍｍを越える厚鋼材が使用されるようになると、上述のように、溶接ボンド部の破壊靱性を確保するために、極端なオーバーマッチングとなる継手設計をさける必要が出てきた。 しかしながら、前述のように、溶接金属の硬さＨｖが２２０以上になると溶接金属の靱性が低下するという重大な問題が生じる。そこで、これまで使用されていなかった高強度厚肉鋼材の大入熱１パス溶接において、溶接金属の硬さが２２０以下であっても十分な破壊靱性が確保できる溶接金属の開発が望まれた。
そこで、本発明は、上記課題に鑑み、高強度で、かつ板厚５０ｍｍを越える厚接においても、溶接継手部における溶接金属の・溶接材料を選定して、目的とする成分の溶接金属を形成し、微細なフェライト組織を主体とした、粒界の粗大フェライトの抑制を行い、溶接金属の硬さを２２０以下で靱性の良好な溶接金属を作成する１電極または２電極エレクトロガスア−ク溶接法を提供するものであり、その要旨とするところは特許請求の範囲に記載した通りの下記内容である。
With the recent increase in size of welded structures, when high strength steel plates with a thickness exceeding 50 mm are used, as described above, in order to ensure the fracture toughness of the weld bond, There is a need to avoid joint design that results in overmatching. However, as described above, when the hardness Hv of the weld metal is 220 or more, there arises a serious problem that the toughness of the weld metal is lowered. In view of this, it has been desired to develop a weld metal capable of ensuring sufficient fracture toughness even in a case where the hardness of the weld metal is 220 or less in a large heat input one-pass welding of a high strength thick steel material that has not been used so far. .
Therefore, in view of the above-mentioned problems, the present invention forms a weld metal having a desired component by selecting a weld metal / weld material in a weld joint even in a high strength and thickness welding exceeding a plate thickness of 50 mm. One-electrode or two-electrode electrogas arc welding that suppresses coarse ferrite at grain boundaries, mainly composed of a fine ferrite structure, and produces a weld metal having a weld metal hardness of 220 or less and good toughness The gist of the present invention is as follows, as described in the claims.
板厚が50ｍｍ以上、80ｍｍ以下の鋼材を、１電極または２電極のうちの少なくとも１電極にフラックス入りワイヤを用いて立向き溶接する１電極または２電極エレクトロガスアーク溶接継ぎ手であって、
溶接金属の各化学成分がmass%で、Ｃ：0.01〜0.10％、Si：0.31〜0.5％、Mn：1.0〜2.0%、Cu:0.07〜0.23％、Ni：0.5〜3.0％、Cr:0.02〜0.03％、Mo：0.5％以下、Ｖ:0.01％以下、Nb:0.002〜0.008％、Ａｌ：0.005〜0.025％、Ｔｉ：0.01〜0.05％、Ｂ：0.003〜0.009％、Ｎ：0.007％以下、Ｏ：0.02〜0.05％、残部Ｆｅおよび不可避的不純物からなる溶接金属組成を有し、かつ溶接金属の硬さがビッカース硬度で２２０以下であり、
下記（Ａ）式で示す溶接金属のCEの値を0.36〜0.42とすることを特徴とする靭性に優れたエレクトロガスアーク溶接継ぎ手。
CE＝C＋Si/24＋Mn/6+（Cu+Ni）/40＋（Cr＋Mo＋V）/5・・・（Ａ）
ここに、C,Si,Mn,Cu,Ni,Cr,Mo,V：溶接金属の各化学成分の平均mass%
A one-electrode or two-electrode electrogas arc welding joint for vertically welding a steel material having a plate thickness of 50 mm or more and 80 mm or less to at least one of one electrode or two electrodes using a flux-cored wire,
Each chemical Ingredients of weld metal in mass%, C: 0.01~0.10%, Si: 0.31 ~0.5%, Mn: 1.0~2.0%, Cu: 0.07~0.23%, Ni: 0.5~3.0%, Cr: 0.02 -0.03%, Mo: 0.5% or less, V: 0.01% or less, Nb: 0.002-0.008%, Al: 0.005-0.025 %, Ti: 0.01-0.05%, B: 0.003-0.009%, N: 0.007% or less, O: 0.02 to 0.05%, having a soluble Sekkin genus composition the balance being Fe and inevitable impurities, and the hardness of the weld metal is not more 220 or less in Vickers hardness,
An electrogas arc welding joint excellent in toughness characterized in that the CE value of the weld metal represented by the following formula (A) is 0.36 to 0.42.
CE = C + Si / 24 + Mn / 6 + (Cu + Ni) / 40 + (Cr + Mo + V) / 5 ... (A)
Here, C, Si, Mn, Cu, Ni, Cr, Mo, V: average mass% of each chemical component of the weld metal
本発明によれば、破壊靱性の確保が難しい厚手大入熱溶接用高強度鋼材（特に降伏強度が360Mpa以上、500MPa程度以下、板厚が50ｍｍ以上、80ｍｍ以下の鋼材が対象）の溶接継手であっても、イーブンマッチングあるいはオーバーマッチングとなる溶接継手設計を可能にして継手部の破壊靱性を確保することができるという顕著な効果を奏する。 According to the present invention, a high strength steel material for thick large heat input welding where it is difficult to ensure fracture toughness (particularly for steel materials having a yield strength of 360 MPa or more and 500 MPa or less, and a plate thickness of 50 mm or more and 80 mm or less) Even if it exists, there exists a remarkable effect that the fracture joint toughness of a joint part can be ensured by enabling the welding joint design used as even matching or overmatching.
本発明は、板厚が50ｍｍ以上、80ｍｍ以下の鋼材を、１電極または２電極のうちの少なくとも１電極にフラックス入りワイヤを用いて立向き溶接する１電極または２電極エレクトロガスアーク溶接継ぎ手であって、
溶接金属の各化学成分のがmass%で、Ｃ：0.01〜0.10％、Si：0.2〜0.5％、Mn：1.0〜2.0%、Ni：0.5〜3.0％、Mo：0.5％以下、Ａｌ：0.005〜0.025％、Ｔｉ：0.01〜0.05％、Ｂ：0.003〜0.009％、Ｎ：0.007％以下、Ｏ：0.02〜0.05％、残部Ｆｅおよび不可避的不純物からなる溶接溶接金属組成を有し、かつ溶接金属の硬さがビッカース硬度で２２０以下であり、下記（Ａ）式で示す溶接金属のCEの値を0.36〜0.42とすることを特徴とする。
CE＝C＋Si/24＋Mn/6+（Cu+Ni）/40＋（Cr＋Mo＋V）/5・・・（Ａ）
ここに、C,Si,Mn,Cu,Ni,Cr,Mo,V：溶接金属の各化学成分の平均mass%
先ず、溶接金属の硬さ（Ｈｖ）を従来は２２０以上に設計していた理由について説明する。
前述のように、従来技術とくに大入熱の立向き溶接においては、粒界フェライトが生成し、特に板厚や開先形状が大きくなった場合に溶接入熱が変化して、冷却時間が長くなっても粒界フェライトが生成し、靭性が低下させないようにするために、溶接金属中の合金成分を高くし粒界フェライトを消滅させていた。この不要に合金成分を多く添加していたために溶接金属の硬さが２２０以上になっていた。
The present invention is a one-electrode or two-electrode electrogas arc welding joint for vertically welding a steel material having a plate thickness of 50 mm or more and 80 mm or less to at least one of one electrode or two electrodes using a flux-cored wire. ,
Each chemical component of the weld metal is mass%, C: 0.01 to 0.10%, Si: 0.2 to 0.5%, Mn: 1.0 to 2.0%, Ni: 0.5 to 3.0%, Mo: 0.5% or less, Al: 0.005 to 0.025%, Ti: 0.01 to 0.05%, B: 0.003 to 0.009%, N: 0.007% or less, O: 0.02 to 0.05%, having a weld weld metal composition consisting of the balance Fe and inevitable impurities, The hardness is 220 or less in terms of Vickers hardness, and the CE value of the weld metal represented by the following formula (A) is 0.36 to 0.42.
CE = C + Si / 24 + Mn / 6 + (Cu + Ni) / 40 + (Cr + Mo + V) / 5 ... (A)
Here, C, Si, Mn, Cu, Ni, Cr, Mo, V: average mass% of each chemical component of the weld metal
First, the reason why the hardness (Hv) of the weld metal is conventionally designed to be 220 or more will be described.
As described above, in the conventional technology, particularly in the vertical welding with high heat input, intergranular ferrite is generated, and particularly when the plate thickness or groove shape is increased, the welding heat input changes and the cooling time becomes longer. Even so, in order to prevent the formation of grain boundary ferrite and decrease the toughness, the alloy components in the weld metal are increased to eliminate the grain boundary ferrite. Since many unnecessary alloy components were added, the hardness of the weld metal was 220 or more.
この問題を解決するには、鋼材の成分や板厚、溶接時の開先形状に制限を加え、溶接施工条件に応じた溶接ワイヤを設計選定する必要があるが、実際の施工現場においては、ある程度の溶接施工条件のばらつきや鋼材、溶接材料の成分変動も許容できる溶接方法でなくては使用できなかった。
そこで、本発明者らは、母材の強度、成分、溶接時の開先形状、溶接施工条件等を考慮し、ある一定の条件範囲内で、溶接材料を選定することにより、目的とする硬さ２２０以下で靱性の良好なエレクトロガスア−ク溶接溶接継ぎ手を得た。
以下に本発明の技術思想を説明する。
まず、Ti-B系溶接金属として、ミクロ組織をアシキュラーフェライトと粒界フェライトの混合組織として、かつ粒界フェライトの体積率を制限することにより、本発明の対象とするような、大入熱溶接であるエレクトロガス溶接方法においても、必要な靭性値と硬さの両方を満たす溶接金属が得られた。
また、靭性の改善と硬さ低減の両者に有害な高炭素マルテンサイトの生成を抑えるためにＣ含有量の低い溶接ワイヤを使用し、ＢとNiを添加した溶接ワイヤを使用すれば、硬さを上昇させることなく靭性を改善できた。
さらに、靭性に有害な窒素（N）量を低減するために、Ｎ含有量の少ない溶接ワイヤを使用し、さらに、好ましくは溶接時にNが極力混入しないようにアーク溶接時のガス流量と溶接電圧を制御することにより、靭性の良好な溶接金属を得る条件を見出した。
In order to solve this problem, it is necessary to limit the composition and thickness of the steel material and the groove shape at the time of welding, and to design and select the welding wire according to the welding conditions, but in the actual construction site, The welding method could not be used unless it could tolerate variations in welding conditions to some extent and fluctuations in the components of steel and welding materials.
Accordingly, the present inventors consider the strength of the base metal, the components, the groove shape during welding, welding conditions, etc., and select the welding material within a certain range of conditions, thereby achieving the desired hardness. An electrogas arc welding weld joint having a toughness of 220 or less was obtained.
The technical idea of the present invention will be described below.
First, as a Ti-B weld metal, the microstructure is a mixed structure of acicular ferrite and grain boundary ferrite, and by limiting the volume fraction of grain boundary ferrite, the large heat input as the object of the present invention. Also in the electrogas welding method which is welding, a weld metal satisfying both the required toughness value and hardness was obtained.
In addition, if a welding wire with a low C content is used to suppress the formation of high carbon martensite, which is harmful to both toughness improvement and hardness reduction, and if a welding wire to which B and Ni are added is used, the hardness It was possible to improve toughness without increasing the.
Furthermore, in order to reduce the amount of nitrogen (N) harmful to toughness, a welding wire with a low N content is used, and preferably the gas flow rate and welding voltage during arc welding so that N is not mixed as much as possible during welding. The condition for obtaining a weld metal with good toughness was found by controlling.
以下に、溶接金属の各化学成分の限定理由を示す。
なお、本発明における化学成分は全てmass%で示す。
Ｃ：0.01〜0.10％は、靭性向上および硬さ低減の点から炭素は低ければ低いほど望ましいが、0.01％を下限としたのは、現実に材料の入手が困難なためと、低炭素を補完するために他の合金成分を多量に添加する必要があり、現実のワイヤ製造上困難が生じる。また0.10％を上限としたのは、炭素が高いと、高炭素マルテンサイト組織が増加し、本検討の主眼である硬さを減じつつミクロ組織を微細化する趣旨に到達できないためである。
Ｓｉ：0.2%〜0.5%は溶接金属の脱酸および強度を高める目的で添加するが、０.2％以下では脱酸の目的を十分達成せず、0.６％を超えると高炭素マルテンサイトなどの脆化組織の生成を助長するためこの範囲とする。
Ｍｎ：１．０〜2.0％は、主として、溶接金属の強度を調整するためにこの範囲とする。Ｍｎが１．０未満であると、強度が低くなるとともに、Ｎｉなどの高価な元素が多量に必要となり、また、溶接金属の脱酸の目的にも不足傾向が生じる。Ｍｎが2.0％を超える量は硬さを２２０以下に抑えるためには不要である。
Ｎｉ：0.5〜3.0％、Ｎｉは靭性を阻害することなく強度を高める元素として使用する。０．５％未満ではその効果が発揮できず、３．０％を超えると溶接高温割れが発生する懸念があり、また高価であるためこの範囲とする。
Below, the reason for limitation of each chemical component of a weld metal is shown.
In addition, all the chemical components in this invention are shown by mass%.
C: 0.01% to 0.10% is more desirable as the carbon is lower in terms of toughness improvement and hardness reduction. However, the lower limit is set to 0.01% because it is difficult to obtain materials in practice, and the low carbon is supplemented. In order to achieve this, it is necessary to add a large amount of other alloy components, which causes difficulty in actual wire production. Moreover, the upper limit is set to 0.10% because if carbon is high, the high carbon martensite structure increases, and it is not possible to reach the purpose of reducing the microstructure while reducing the hardness, which is the main focus of this study.
Si: 0.2% to 0.5% is added for the purpose of increasing the deoxidation and strength of the weld metal. However, if the content is less than 0.2%, the purpose of deoxidation is not sufficiently achieved, and if it exceeds 0.6%, high carbon martensite is added. In order to promote the formation of a brittle structure such as
Mn: 1.0 to 2.0% is mainly in this range in order to adjust the strength of the weld metal. If Mn is less than 1.0, the strength is lowered, and a large amount of expensive elements such as Ni are required, and the purpose of deoxidizing the weld metal tends to be insufficient. An amount of Mn exceeding 2.0% is not necessary for suppressing the hardness to 220 or less.
Ni: 0.5 to 3.0%, Ni is used as an element that increases strength without inhibiting toughness. If it is less than 0.5%, the effect cannot be exhibited, and if it exceeds 3.0%, there is a concern that hot welding cracks may occur, and since it is expensive, it is within this range.
Ｍｏ：０．５％以下は溶接金属の強度の調整の目的で添加する。
Ａｌ：0.005〜0.025％は、溶接金属の脱酸を目的に添加するが、0.005％未満では十分ではなく、0.025％を超えると、他のＴｉやＢの歩留まりに影響して、溶接金属のミクロ組織が変化するため、この範囲に制御する必要がある。
Ｔｉ：0.01〜0.05％は、溶接金属にアシキュラーフェライトを生成させ、その靭性を向上させるのに最も重要な元素であり、溶接金属中の酸素量にも依存するが、溶接金属中に0.01〜0.05％程度の存在が必要である。
Ｂ：0.003〜0.009％は、溶接金属の硬さを大きく上昇させないで粒界フェライト組織を減少させ、靭性を改善できるために、本目的を達成するのに非常に重要な元素である。したがって溶接金属中に最低30ｐｐｍの含有が必要であり、90ｐｐｍを超えると高温われが発生する。
Ｎ：0.00７％以下は、低ければ低いほど望ましいが、現在の商業ベースでの材料の製造性を考慮すると溶接金属のＮ含有量の下限はせいぜい20ｐｐｍ程度である。上限を７０ｐｐｍとしたのは、多くなると、溶接金属の靭性を低下させるためである。
Ｏ：0.02〜0.05％、Ｏはアシキュラーフェライト生成のための重要元素であるが、エレクトロガス溶接金属では少なくとも0.02％以下にすることは難しく、0.05％以上になると靭性が低下することからこの範囲とした。
次に、硬さについては、靭性、強度と密接な関係があり、溶接金属の炭素量を低減し、溶接施工条件を検討することにより溶接ワイヤ、鋼材の板厚、成分を考慮しつつ溶接金属の成分を（Ａ）式で示す溶接金属のCE（炭素当量）の値を0.36〜0.42の範囲に制御することが必要であった。これらにより、ビッカース硬度で２２０を超えずに、良好な靭性を示す溶接継ぎ手を得られた。
CE＝C＋Si/24＋Mn/6+（Cu+Ni）/40＋（Cr＋Mo＋V）/5・・・（Ａ）
ここに、C,Si,Mn,Cu,Ni,Cr,Mo,V：溶接金属の各化学成分の平均mass%
なお、上記の化学成分以外についてはＦｅおよび不可避的不純物が含まれる。
Mo: 0.5% or less is added for the purpose of adjusting the strength of the weld metal.
Al: 0.005 to 0.025% is added for the purpose of deoxidation of the weld metal, but less than 0.005% is not sufficient, and if it exceeds 0.025%, it affects the yield of other Ti and B, resulting in a microscopic weld metal. Because the organization changes, it is necessary to control within this range.
Ti: 0.01-0.05% is the most important element for generating acicular ferrite in the weld metal and improving its toughness, and depending on the amount of oxygen in the weld metal, The presence of about 0.05% is necessary.
B: 0.003 to 0.009% is an extremely important element for achieving this object because the grain boundary ferrite structure can be reduced and the toughness can be improved without greatly increasing the hardness of the weld metal. Therefore, it is necessary to contain at least 30 ppm in the weld metal, and when it exceeds 90 ppm, high temperature cracking occurs.
N: 0.007% or less is desirable as it is lower, but considering the manufacturability of materials on the current commercial basis, the lower limit of the N content of the weld metal is at most about 20 ppm. The reason why the upper limit is set to 70 ppm is to reduce the toughness of the weld metal if the upper limit is increased.
O: 0.02 to 0.05%, O is an important element for the formation of acicular ferrite, but it is difficult to make it at least 0.02% or less with electrogas welding metal. It was.
Next, hardness has a close relationship with toughness and strength, and reduces the amount of carbon in the weld metal and considers the welding conditions by considering the welding wire, steel thickness, and components. It was necessary to control the CE (carbon equivalent) value of the weld metal represented by the formula (A) in the range of 0.36 to 0.42. As a result, a weld joint exhibiting good toughness was obtained without exceeding 220 in Vickers hardness.
CE = C + Si / 24 + Mn / 6 + (Cu + Ni) / 40 + (Cr + Mo + V) / 5 ... (A)
Here, C, Si, Mn, Cu, Ni, Cr, Mo, V: average mass% of each chemical component of the weld metal
In addition to the above chemical components, Fe and inevitable impurities are included.
板厚：５０、６０、７０、８０の厚鋼材（耐力360.400.470Ｎ／ｍｍ2級鋼）を準備し、図１に示す開先形状にて、エレクトロガスアーク溶接を実施した。溶接に供したワイヤは、ソリッドワイヤは製作上の難しさから4種類とし、主にフラックス入りワイヤの成分を調整して溶接金属を作成した。
使用した鋼材の化学成分と硬さを表１に示す。
使用した溶接条件を表２に示す。
使用したソリッドワイヤの化学成分を表３に示す。
使用したフラックス入りワイヤの化学成分を表４に示す。
得られた溶接部の特性を表５に示す。
なお、溶接金属の性能評価として、−２０℃において切り欠き位置が溶接金属の中央となるように加工した試験片を用いてＶノッチシャルピー衝撃試験を実施した３本の平均値で評価した。
Table 1 shows the chemical composition and hardness of the steel materials used.
Table 2 shows the welding conditions used.
Table 3 shows the chemical composition of the solid wire used.
Table 4 shows the chemical components of the flux-cored wires used.
Table 5 shows the characteristics of the obtained welded portion.
In addition, as performance evaluation of a weld metal, it evaluated by the average value of three which implemented the V notch Charpy impact test using the test piece processed so that a notch position might become the center of a weld metal in -20 degreeC.
また、図２に示した破壊靭性試験は溶接ボンド部にノッチを配置した中央切り欠き付きのディープノッチ試験により評価した。
表５に示すように、本発明で規定する条件を満足する溶接Ｎｏ.は、溶接金属の硬さＨｖが２２０以下でかつ母材の平均硬さ以上を示すもので、溶接金属部において十分なシャルピー衝撃吸収エネルギーを示した。
一方、表５の比較例の溶接Ｎｏ.は、溶接状況の欄に記載した通り、必要強度が不足するもの、溶接金属の焼入れ性が不足し粒界フェライトが2０％を越してシャルピー衝撃吸収エネルギーが低下するもの、溶接金属の硬さが２２０を超えるもの、及び溶接時にヒ゛ート゛表面形状が乱れて健全な溶接部が得られないものなどの比較例である。
In addition, the fracture toughness test shown in FIG. 2 was evaluated by a deep notch test with a central notch in which a notch is arranged in the weld bond portion.
As shown in Table 5, the welding No. satisfying the conditions specified in the present invention is one in which the hardness Hv of the weld metal is 220 or less and the average hardness of the base metal is higher, and is sufficient in the weld metal part. Charpy impact absorption energy was shown.
On the other hand, the welding No. of the comparative example of Table 5 is that the required strength is insufficient as described in the column of welding status, the hardenability of the weld metal is insufficient, and the grain boundary ferrite exceeds 20%, and the Charpy impact absorption energy. Comparative examples include those in which the hardness of the weld metal exceeds 220, and those in which the weld surface shape is disturbed during welding and a healthy weld cannot be obtained.
以上説明したように、本発明は、降伏強度が360Ｎ/ｍｍ2以上の高強度で、かつ板厚５０ｍｍを越える厚鋼材の大入熱エレクトロガスアーク溶接において、溶接継手部におけるＨＡＺ軟化部があっても、溶接金属の硬さを２２０以下、かつ鋼材の平均硬さ以上と制御することにより十分なボンド部の破壊靱性を確保しうる溶接金属を提供することが可能となり、本技術は広くその効果を発揮できるものである。 As described above, the present invention has a HAZ softened portion in a welded joint in high heat input electrogas arc welding of a thick steel material having a high yield strength of 360 N / mm 2 or more and a plate thickness exceeding 50 mm. However, by controlling the hardness of the weld metal to 220 or less and the average hardness of the steel material or more, it becomes possible to provide a weld metal that can ensure sufficient fracture toughness of the bond portion, and the present technology is widely effective. Can be demonstrated.
Claims (1)
溶接金属の各化学成分がmass%で、Ｃ：0.01〜0.10％、Si：0.31〜0.5％、Mn：1.0〜2.0%、Cu:0.07〜0.23％、Ni：0.5〜3.0％、Cr:0.02〜0.03％、Mo：0.5％以下、Ｖ:0.01％以下、Nb:0.002〜0.008％、Ａｌ：0.005〜0.025％、Ｔｉ：0.01〜0.05％、Ｂ：0.003〜0.009％、Ｎ：0.007％以下、Ｏ：0.02〜0.05％、残部Ｆｅおよび不可避的不純物からなる溶接金属組成を有し、かつ溶接金属の硬さがビッカース硬度で２２０以下であり、
下記（Ａ）式で示す溶接金属のCEの値を0.36〜0.42とすることを特徴とする靭性に優れたエレクトロガスアーク溶接継ぎ手。
CE＝C＋Si/24＋Mn/6+（Cu+Ni）/40＋（Cr＋Mo＋V）/5・・・（Ａ）
ここに、C,Si,Mn,Cu,Ni,Cr,Mo,V：溶接金属の各化学成分の平均mass% A one-electrode or two-electrode electrogas arc welding joint for vertically welding a steel material having a plate thickness of 50 mm or more and 80 mm or less to at least one of one electrode or two electrodes using a flux-cored wire,
Each chemical Ingredients of weld metal in mass%, C: 0.01~0.10%, Si: 0.31 ~0.5%, Mn: 1.0~2.0%, Cu: 0.07~0.23%, Ni: 0.5~3.0%, Cr: 0.02 -0.03%, Mo: 0.5% or less, V: 0.01% or less, Nb: 0.002-0.008%, Al: 0.005-0.025 %, Ti: 0.01-0.05%, B: 0.003-0.009%, N: 0.007% or less, O: 0.02 to 0.05%, having a soluble Sekkin genus composition the balance being Fe and inevitable impurities, and the hardness of the weld metal is not more 220 or less in Vickers hardness,
An electrogas arc welding joint excellent in toughness characterized in that the CE value of the weld metal represented by the following formula (A) is 0.36 to 0.42.
CE = C + Si / 24 + Mn / 6 + (Cu + Ni) / 40 + (Cr + Mo + V) / 5 ... (A)
Here, C, Si, Mn, Cu, Ni, Cr, Mo, V: average mass% of each chemical component of the weld metal
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| JP2010115701A (en) * | 2008-11-14 | 2010-05-27 | Kobe Steel Ltd | High strength weld metal with excellent low-temperature toughness |
| JP6782580B2 (en) * | 2016-08-04 | 2020-11-11 | 株式会社神戸製鋼所 | Arc spot welding method |
| CN107662064A (en) * | 2017-11-16 | 2018-02-06 | 天津大桥焊材集团有限公司 | A kind of 900MPa levels welding Shielding Solid Welding Wire |
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