JP2011000626A - Weld metal - Google Patents

Weld metal Download PDF

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JP2011000626A
JP2011000626A JP2009147129A JP2009147129A JP2011000626A JP 2011000626 A JP2011000626 A JP 2011000626A JP 2009147129 A JP2009147129 A JP 2009147129A JP 2009147129 A JP2009147129 A JP 2009147129A JP 2011000626 A JP2011000626 A JP 2011000626A
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JP5244035B2 (en
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Masaki Shimamoto
正樹 島本
Hitoshi Ishida
斉 石田
Koichi Sakamoto
浩一 坂本
Hideji Sasakura
秀司 笹倉
Tomoki Kakizaki
智紀 柿崎
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Kobe Steel Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a weld metal that excels in hot crack resistance and mechanical properties.SOLUTION: The weld metal contains, by mass, 0.01-0.10% C, ≤0.7% Si, 0.5-3.0% Mn, 0.05-0.50% Ti, 0.02-0.10% Al, 0.03-0.10% O, 0.0002-0.01% Mg, ≤003% P, ≤0.02% S, 0.002-0.01% N, 0.0003-0.005% B, and the balance Fe with inevitable impurities. Also, the ratios of metallic elements constituting Ti-Al-Si-Mn-Mg-based oxide contained in the weld metal and having a circle-equivalent diameter of 0.5-5.0 μm are in the range in atomic % of 30-70% Ti, 30-70% Al, ≤15% Si, ≤15% Mn, and ≤10% Mg.

Description

本発明は、軟鋼、高張力鋼等からなる鋼板のガスシールドアーク溶接に適用されるフラックス入りワイヤにより溶接された溶接金属に関するものである。   The present invention relates to a weld metal welded by a flux-cored wire applied to gas shielded arc welding of a steel plate made of mild steel, high-strength steel, or the like.

従来、鋼板のガスシールドアーク溶接において、溶接金属の耐高温割れ性と靭性を向上させるために、次のような溶接金属が提案されている。例えば、特許文献1では、溶接線材のS含有量を0.0020%以下に制限することが提案されている。また、特許文献2では、溶接ワイヤの材料成分を、イオウ(S)量:0.004〜0.010%、ディロング線図によるフェライト量:10〜15%に調節することが提案されている。   Conventionally, in the gas shielded arc welding of steel plates, the following weld metals have been proposed in order to improve the hot cracking resistance and toughness of the weld metal. For example, Patent Document 1 proposes that the S content of the welding wire is limited to 0.0020% or less. Patent Document 2 proposes to adjust the material component of the welding wire to a sulfur (S) amount of 0.004 to 0.010% and a ferrite amount of 10-15% according to a long diagram.

特許文献3では、溶接金属組織におけるδフェライト量が3体積%以上となるように、溶融凝固時の金属組織におけるδフェライト量が少なくとも3体積%以上であるオーステナイト系ステンレス鋼製の溶接棒,溶接芯線又はバンドアーク鋼帯とフラックスを組み合わせた溶接材料が提案されている。特許文献4では、C:0.03mass%以下、B:0.0030mass%以下、S:0.010mass%以下の鋼板と、C:0.03〜0.10mass%、S:0.003〜0.015mass%を含有するソリッドワイヤを用いることが提案されている。   In Patent Document 3, a welding rod and weld made of austenitic stainless steel in which the amount of δ ferrite in the metal structure at the time of melt solidification is at least 3% by volume so that the amount of δ ferrite in the weld metal structure is 3% by volume or more. A welding material combining a core wire or a band arc steel strip and a flux has been proposed. In patent document 4, C: 0.03 mass% or less, B: 0.0030 mass% or less, S: 0.010 mass% or less steel plate, C: 0.03-0.10 mass%, S: 0.003-0 It has been proposed to use a solid wire containing .015 mass%.

また、溶接金属の凝固組織を微細分散させ、高温割れの主要因であるP、S、B等が偏析した最終凝固部分の低融点の共晶領域を微細分散させることで、耐高温割れ性が向上することに着目し、次のような手法も提案されている。例えば、特許文献5では、溶接後の溶接金属組織中に最大径0.01〜10.00μmの希土類元素の窒化物もしくはさらに酸化物との複合析出物を、任意の断面において1個/mm以上残存させて溶接金属の組織を微細にする溶接材料が提案されている。また、特許文献6では、溶接ワイヤの成分を調整することで、Ti又はAlの窒化物の粒子サイズが0.3μm以上で、1.5×10個/mm以上の密度で存在する溶接部を得ることが提案されている。 In addition, the solidification structure of the weld metal is finely dispersed, and the low-melting eutectic region of the final solidified portion where P, S, B, etc., which are the main causes of hot cracking, are finely dispersed, thereby providing high temperature cracking resistance. Focusing on the improvement, the following methods have also been proposed. For example, in Patent Document 5, a rare earth element nitride having a maximum diameter of 0.01 to 10.00 μm or a composite precipitate with an oxide in a weld metal structure after welding is 1 piece / mm 2 in an arbitrary cross section. There has been proposed a welding material that remains to make the microstructure of the weld metal finer. Moreover, in patent document 6, the particle size of the nitride of Ti or Al is 0.3 micrometer < 2 > or more by adjusting the component of a welding wire, and it exists with the density of 1.5 * 10 < 4 > piece / mm < 2 > or more. It has been proposed to obtain a weld.

特開昭54−130452号公報Japanese Patent Laid-Open No. 54-130552 特開2008−55462号公報JP 2008-55462 A 特開平9−267191号公報Japanese Patent Laid-Open No. 9-267191 特開2000−317681号公報JP 2000-317681 A 特開2003−1484号公報JP 2003-1484 A 特開2002−336990号公報JP 2002-336990 A

特許文献1に記載された発明では、溶接能率が向上した近年の溶接施工条件に拡大して適用することは困難である。また、低温靭性確保の観点からB量低減が困難な場合があるとともに、S等の不純物元素の低減にも限界があるため、溶接金属に発生する高温割れを完全には抑制できない。また、特許文献2〜4に記載された発明では、溶接金属のフェライト量に影響するC濃度が、溶接時に母材を希釈するため、母材希釈量の影響を受けて高温割れが発生しやすい初層のδフェライト量が不安定になりやすいため、安定した耐高温割れ特性を得ることが困難である。また、特許文献5,6に記載された発明では、凝固組織の微細化に窒化物を利用しているため、多量のN添加が不可欠であり、溶接金属の低温靭性の低下やブローホールの発生を引き起こす問題があった。   In the invention described in Patent Document 1, it is difficult to expand and apply to recent welding conditions in which welding efficiency is improved. In addition, there is a case where it is difficult to reduce the amount of B from the viewpoint of securing low temperature toughness, and there is a limit to the reduction of impurity elements such as S, so that high temperature cracks generated in the weld metal cannot be completely suppressed. In the inventions described in Patent Documents 2 to 4, since the C concentration that affects the ferrite content of the weld metal dilutes the base material during welding, hot cracking is likely to occur due to the influence of the base material dilution amount. Since the amount of δ ferrite in the first layer tends to be unstable, it is difficult to obtain stable hot cracking resistance. In addition, in the inventions described in Patent Documents 5 and 6, since nitride is used for refining the solidified structure, a large amount of N is indispensable, and the low-temperature toughness of the weld metal is reduced and blowholes are generated. There was a problem causing.

本発明は、前記課題に鑑みてなされたもので、耐高温割れ性、および溶接金属の機械的性質に優れた溶接金属を提供することを目的とする。   The present invention has been made in view of the above problems, and an object of the present invention is to provide a weld metal excellent in hot crack resistance and mechanical properties of the weld metal.

前記課題を解決するために、本発明に係る溶接金属は、鋼製外皮内にフラックスが充填されたフラックス入りワイヤにより溶接された溶接金属であって、C:0.01〜0.10質量%、Si:0.7質量%以下、Mn:0.5〜3.0質量%、Ti:0.05〜0.50質量%、Al:0.02〜0.10質量%、O:0.03〜0.10質量%、Mg:0.0002〜0.01質量%、P:0.03質量%以下、S:0.02質量%以下、N:0.002〜0.01質量%、B:0.0003〜0.005質量%、を含有し、残部がFeおよび不可避的不純物からなり、かつ、前記溶接金属に含まれる円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率が、Ti:30〜70原子%、Al:30〜70原子%、Si:15原子%以下(0原子%を含む)、Mn:15原子%以下(0原子%を含む)、Mg:10原子%以下(0原子%を含む)、の範囲内である(ただし、Ti+Al+Si+Mn+Mg=100原子%とする)構成とする。   In order to solve the above problems, a weld metal according to the present invention is a weld metal welded with a flux-cored wire in which a steel outer shell is filled with a flux, and C: 0.01 to 0.10% by mass , Si: 0.7 mass% or less, Mn: 0.5 to 3.0 mass%, Ti: 0.05 to 0.50 mass%, Al: 0.02 to 0.10 mass%, O: 0.0. 03 to 0.10% by mass, Mg: 0.0002 to 0.01% by mass, P: 0.03% by mass or less, S: 0.02% by mass or less, N: 0.002 to 0.01% by mass, B: 0.0003-0.005 mass%, the balance is made of Fe and inevitable impurities, and the equivalent circle diameter contained in the weld metal is 0.5-5.0 μm Ti—Al— The ratio of the metal elements constituting the Si-Mn-Mg oxide is Ti: 30 to 70 atomic%, A : 30-70 atomic%, Si: 15 atomic% or less (including 0 atomic%), Mn: 15 atomic% or less (including 0 atomic%), Mg: 10 atomic% or less (including 0 atomic%) The structure is within the range (however, Ti + Al + Si + Mn + Mg = 100 atomic%).

かかる構成によれば、溶接金属に所定量のC、Si、Mn、Ti、Al、O、Mg、P、S、N、Bを含有するとともに、前記溶接金属に含まれる円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成するTiおよびAlの比率を可能な限り多く、Si、MnおよびMgの比率を可能な限り少なくすることにより、溶接金属の凝固組織のδフェライト組織が微細化し、溶接金属の耐高温割れ特性が著しく改善する。   According to this configuration, the weld metal contains a predetermined amount of C, Si, Mn, Ti, Al, O, Mg, P, S, N, and B, and the equivalent circle diameter contained in the weld metal is 0. By increasing the ratio of Ti and Al constituting the 5-5.0 μm Ti—Al—Si—Mn—Mg-based oxide as much as possible and reducing the ratio of Si, Mn and Mg as much as possible, the weld metal The δ ferrite structure of the solidified structure becomes finer, and the hot cracking resistance of the weld metal is remarkably improved.

また、請求項2に係る溶接金属は、希土類元素の1種または2種以上を、合計0.01質量%以下含有する構成とする。   The weld metal according to claim 2 is configured to contain one or more rare earth elements in a total amount of 0.01% by mass or less.

かかる構成によれば、溶接金属に所定量の希土類元素をさらに含有することによって、溶接金属中の介在物から、希土類元素に比べて脱酸力の弱いSi、Mnからなる酸化物を還元し、溶接金属の凝固組織微細化に有効なTi−Al−Si−Mn−Mg系酸化物の制御を促進する。   According to such a configuration, by further containing a predetermined amount of rare earth element in the weld metal, from the inclusions in the weld metal, an oxide made of Si, Mn having a weaker deoxidizing power than the rare earth element is reduced, Control of Ti-Al-Si-Mn-Mg based oxide effective for refinement of solidification structure of weld metal is promoted.

また、請求項3に係る溶接金属は、Cu、Ni、Cr、Mo、Nb、およびVからなる群から選択された少なくとも1種の元素を、合計0.5質量%以下含有する構成とする。   Further, the weld metal according to claim 3 is configured to contain a total of 0.5% by mass or less of at least one element selected from the group consisting of Cu, Ni, Cr, Mo, Nb, and V.

かかる構成によれば、上記元素が溶接金属の凝固組織微細化に有効なTi−Al−Si−Mn−Mg系酸化物に影響を与えることがない。   According to such a configuration, the element does not affect the Ti—Al—Si—Mn—Mg-based oxide effective for refining the solidification structure of the weld metal.

請求項1に係る溶接金属によれば、溶接金属の低温靭性を向上させ、かつ、鋼板の片面突合せ継手溶接の初層溶接部で問題となる高温割れを抑制することができる。さらに溶接金属の機械的性質も向上させることができる。   According to the weld metal which concerns on Claim 1, the low temperature toughness of a weld metal can be improved, and the hot crack which becomes a problem in the first layer welding part of the single-sided butt joint welding of a steel plate can be suppressed. Furthermore, the mechanical properties of the weld metal can also be improved.

請求項2に係る溶接金属によれば、溶接金属の低温靭性がさらに向上し、かつ、鋼板の片面突合せ継手溶接の初層溶接部で問題となる高温割れを好適に抑制することができる。さらに溶接金属の機械的性質も向上させることができる。   According to the weld metal which concerns on Claim 2, the low temperature toughness of a weld metal can further improve, and the high temperature crack which becomes a problem in the first layer welding part of the single-sided butt joint welding of a steel plate can be suppressed suitably. Furthermore, the mechanical properties of the weld metal can also be improved.

請求項3に係る溶接金属によれば、溶接金属の低温靭性がさらに向上し、かつ、鋼板の片面突合せ継手溶接の初層溶接部で問題となる高温割れを好適に抑制することができる。さらに溶接金属の機械的性質も向上させることができる。   According to the weld metal which concerns on Claim 3, the low temperature toughness of a weld metal can further improve, and the high temperature crack which becomes a problem in the first layer welding part of the single-sided butt joint welding of a steel plate can be suppressed suitably. Furthermore, the mechanical properties of the weld metal can also be improved.

耐高温割れ性の評価に使用する溶接母材の開先形状を示す断面図である。It is sectional drawing which shows the groove shape of the welding preform | base_material used for evaluation of hot cracking resistance.

本発明では、耐高温割れ特性を著しく改善した溶接金属を提供するため、凝固組織を微細化するTi−Al−Si−Mn−Mg系酸化物を構成する元素に着眼した。その結果、耐高温割れ特性を著しく改善した溶接金属を得るためには、円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成する元素の比率を適切に制御することが極めて重要であり、従来に比べてSi、MnおよびMgを可能な限り少なく、TiおよびAlを可能な限り多く含むTi−Al−Si−Mn−Mg系酸化物が、凝固組織のδフェライト組織の微細化に有効であり、溶接金属の耐高温割れ特性を著しく改善させることを知見した。   In the present invention, in order to provide a weld metal that has remarkably improved hot cracking resistance, the present inventors have focused on elements that constitute a Ti—Al—Si—Mn—Mg oxide that refines the solidification structure. As a result, in order to obtain a weld metal with significantly improved hot cracking resistance, the ratio of elements constituting the Ti-Al-Si-Mn-Mg-based oxide having an equivalent circle diameter of 0.5 to 5.0 μm is set. Proper control is extremely important, and Ti-Al-Si-Mn-Mg-based oxides containing as much Si and Mn and Mg as possible and containing as much Ti and Al as possible in comparison with the past are solidified. It has been found that it is effective in refining the δ ferrite structure of the structure and significantly improves the hot cracking resistance of the weld metal.

そして、上記組成の酸化物を含む溶接金属を得るためには、従来のようにTiO主体のフラックス入りワイヤの特長である全姿勢溶接を確保するためにSi源を多量に添加したワイヤではなく、逆にSi源を低減し、Al源、Mg源およびTi源を増量したワイヤを用いる必要がある。これにより、溶接金属の凝固段階でTi−Al−Si−Mn−Mg系酸化物が生成され、溶接金属の凝固組織が微細化するとともに、最終凝固部分の低融点の液膜が分散し、耐高温割れ性が著しく改善する。 And, in order to obtain a weld metal containing an oxide having the above composition, it is not a wire in which a large amount of Si source is added in order to ensure all-position welding, which is a feature of a flux-cored wire mainly composed of TiO 2. Conversely, it is necessary to use wires in which the Si source is reduced and the Al source, Mg source, and Ti source are increased. As a result, a Ti-Al-Si-Mn-Mg-based oxide is produced at the solidification stage of the weld metal, the solidification structure of the weld metal is refined, and the low melting point liquid film in the final solidification portion is dispersed, resulting in resistance to resistance. Hot cracking property is remarkably improved.

また、上述のように、従来のTiO主体のフラックス入りワイヤは、全姿勢溶接が可能なワイヤとして汎用されているが、その理由は、溶接金属表面をTiOとSiOとMnOからなるスラグが覆い、溶接金属が垂れ落ちることを防止しているためである。従って、従来のフラックス入りワイヤでは、溶接金属中に生成する酸化物の大部分はTiO、SiO、MnOからなる複合酸化物である。この酸化物は融点が低く、溶接金属の凝固段階では液体として存在している。 Further, as described above, the conventional flux-cored wire mainly composed of TiO 2 is widely used as a wire that can be welded in all positions, because the surface of the weld metal is made of TiO 2 , SiO 2, and MnO. This is because the covering prevents the weld metal from dripping. Therefore, in the conventional flux-cored wire, most of the oxide generated in the weld metal is a composite oxide composed of TiO 2 , SiO 2 , and MnO. This oxide has a low melting point and exists as a liquid in the solidification stage of the weld metal.

一方、本発明では、脱酸力の弱いSi源およびMn源を低減し、脱酸力の強いTi源、Al源およびMg源を増量することで、溶接金属中の酸化物から脱酸力の弱いSiOやMnOを還元し、TiOとAlが主体となる複合酸化物に制御した。この酸化物は、TiOとAl主体の複合酸化物であるTi−Al−Si−Mn−Mg系酸化物であり、融点が高く、溶接金属の凝固段階では既に凝固して固体として存在している。従って、溶接金属の凝固組織のδフェライト相とTiOとAl主体の複合酸化物であるTi−Al−Si−Mn−Mg系酸化物との格子整合性が向上し、凝固組織が微細化する。 On the other hand, in the present invention, by reducing the Si source and Mn source having weak deoxidizing power and increasing the amount of Ti source, Al source and Mg source having strong deoxidizing power, the deoxidizing power is reduced from the oxide in the weld metal. Weak SiO 2 and MnO were reduced to control a composite oxide mainly composed of TiO 2 and Al 2 O 3 . This oxide is a Ti—Al—Si—Mn—Mg based oxide which is a composite oxide mainly composed of TiO 2 and Al 2 O 3 , has a high melting point, and has already solidified and solidified in the solidification stage of the weld metal. Existing. Accordingly, the lattice matching between the δ ferrite phase of the solidified structure of the weld metal and the Ti—Al—Si—Mn—Mg based oxide which is a composite oxide mainly composed of TiO 2 and Al 2 O 3 is improved, and the solidified structure is improved. Refine.

なお、全姿勢溶接性に関しても、従来のTiOを主体としたフラックス入りワイヤを用いた溶接金属と比較して、本発明の溶接金属はAl、MgOおよびTiOからなるスラグに覆われ、スラグ物性が従来のスラグ物性と同等になるため、溶接金属が垂れ落ちることがない。以下に、本発明に係る溶接金属成分の数値範囲を、その限定理由と共に記載する。 As for all-position weldability, the weld metal of the present invention is covered with a slag composed of Al 2 O 3 , MgO and TiO 2 as compared with a weld metal using a flux-cored wire mainly composed of TiO 2. Since the slag physical properties are equivalent to the conventional slag physical properties, the weld metal does not sag. Below, the numerical range of the weld metal component which concerns on this invention is described with the reason for limitation.

本発明に係る溶接金属は、C:0.01〜0.10質量%、Si:0.7質量%以下、Mn:0.5〜3.0質量%、Ti:0.05〜0.50質量%、Al:0.02〜0.10質量%、O:0.03〜0.10質量%、Mg:0.0002〜0.01質量%、P:0.03質量%以下、S:0.02質量%以下、N:0.002〜0.01質量%、B:0.0003〜0.005質量%、を含有し、残部がFeおよび不可避的不純物からなる。また、溶接金属に含まれる円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率が、Ti:30〜70原子%、Al:30〜70原子%、Si:15原子%以下(0原子%を含む)、Mn:15原子%以下(0原子%を含む)、Mg:10原子%以下(0原子%を含む)、の範囲内である(ただし、Ti+Al+Si+Mn+Mg=100原子%とする)ことを特徴とする。なお、上記元素の含有量は、後述のようにフラックス入りワイヤの組成を調整することによって制御することができる。   The weld metal according to the present invention includes C: 0.01 to 0.10% by mass, Si: 0.7% by mass or less, Mn: 0.5 to 3.0% by mass, Ti: 0.05 to 0.50. % By mass, Al: 0.02-0.10% by mass, O: 0.03-0.10% by mass, Mg: 0.0002-0.01% by mass, P: 0.03% by mass or less, S: 0.02 mass% or less, N: 0.002-0.01 mass%, B: 0.0003-0.005 mass%, and remainder consists of Fe and an unavoidable impurity. Moreover, the ratio of the metal element which comprises the Ti-Al-Si-Mn-Mg type | system | group oxide whose circle equivalent diameter contained in a weld metal is 0.5-5.0 micrometers is Ti: 30-70 atomic%, Al: 30 to 70 atomic%, Si: 15 atomic% or less (including 0 atomic%), Mn: 15 atomic% or less (including 0 atomic%), Mg: 10 atomic% or less (including 0 atomic%) (However, Ti + Al + Si + Mn + Mg = 100 atomic%). In addition, content of the said element is controllable by adjusting the composition of a flux cored wire so that it may mention later.

(C:0.01〜0.10質量%)
Cは、溶接金属の焼入れ性を確保するために添加する。C量が0.01質量%未満では、焼入れ性不足により、溶接金属の強度・靭性が不足する。また、低C量により溶接金属に高温割れが発生しやすくなる。C量が0.10質量%を超えると、溶接金属の固相線温度が低下しすぎるため、凝固組織微細化による溶接金属の耐高温割れ性改善効果を打消し、高温割れが発生しやすくなる。よって、C量は、0.01〜0.10質量%とすることが望ましい。
(C: 0.01 to 0.10% by mass)
C is added to ensure the hardenability of the weld metal. When the amount of C is less than 0.01% by mass, the strength and toughness of the weld metal is insufficient due to insufficient hardenability. Moreover, it becomes easy to generate a hot crack in the weld metal due to the low C content. If the amount of C exceeds 0.10% by mass, the solidus temperature of the weld metal is too low, so the effect of improving the resistance to hot cracking of the weld metal by refining the solidification structure is canceled and hot cracking is likely to occur. . Therefore, it is desirable that the C amount be 0.01 to 0.10% by mass.

(Si:0.7質量%以下)
Siは、P、S同様に溶接金属の最終凝固部で低融点の共晶反応を起こし、高温割れを助長する。さらに、脱酸元素でもあり、溶接金属中の介在物をSiを含んだ酸化物とし、凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物に制御できなくなるため、高温割れが発生しやすくなる。よって、Si量は、0.7質量%以下とすることが望ましい。
(Si: 0.7 mass% or less)
Si, like P and S, causes a low-melting eutectic reaction in the final solidified portion of the weld metal and promotes hot cracking. Furthermore, it is also a deoxidizing element, and inclusions in the weld metal are made into oxides containing Si, and it becomes impossible to control Ti-Al-Si-Mn-Mg-based oxides effective for refining the solidification structure. Cracks are likely to occur. Therefore, the Si amount is desirably 0.7% by mass or less.

(Mn:0.5〜3.0質量%)
Mnは不可避的不純物として含有されるSと結合してMnSを生成し、耐高温割れ性を改善する効果がある。Mn量が0.5質量%未満では、MnSによる高温割れの抑制作用が小さくなり、溶接部に高温割れが発生する。また、Mnは脱酸元素でもあり、溶接金属中の介在物をMnを含んだ酸化物とし、凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物に制御できなくなるため、高温割れが発生しやすくなる。よって、Mn量は、3.0質量%以下とすることが望ましい。
(Mn: 0.5 to 3.0% by mass)
Mn combines with S contained as an inevitable impurity to produce MnS, and has the effect of improving hot cracking resistance. When the amount of Mn is less than 0.5% by mass, the effect of suppressing hot cracking by MnS is reduced, and hot cracking occurs in the welded portion. In addition, Mn is also a deoxidizing element, and inclusions in the weld metal are converted to oxides containing Mn, and cannot be controlled to Ti-Al-Si-Mn-Mg-based oxides that are effective in reducing the solidification structure. , Hot cracking is likely to occur. Therefore, the amount of Mn is desirably 3.0% by mass or less.

(Ti:0.05〜0.50質量%)
Tiは、溶接金属の耐高温割れ性を改善するために添加する。Tiは溶接時に脱酸反応に寄与し、溶接金属中の介在物がTi−Al−Si−Mn−Mg系酸化物組成に制御でき、その結果、溶接金属の凝固組織を微細にでき、溶接部の耐高温割れ性が改善される。Ti量が0.05質量%未満では、上記効果が充分では無く、溶接部に高温割れが発生する。Ti量が0.50質量%を超えると、溶接金属中の酸化物はTi−Al−Si−Mn−Mg系酸化物となり凝固組織が微細化し耐高温割れ性は改善するが、Ti量の大部分が溶存し、溶接金属の凝固温度を低下させるため凝固組織微細化による耐高温割れ性改善効果を上回って高温割れが発生しやすくなる。よって、Ti量は、0.05〜0.50質量%とすることが望ましい。
(Ti: 0.05 to 0.50 mass%)
Ti is added to improve the hot cracking resistance of the weld metal. Ti contributes to a deoxidation reaction during welding, and inclusions in the weld metal can be controlled to a Ti—Al—Si—Mn—Mg oxide composition. As a result, the solidification structure of the weld metal can be made fine, and the weld zone The hot cracking resistance of is improved. When the amount of Ti is less than 0.05% by mass, the above effect is not sufficient, and hot cracks occur in the welded portion. When the amount of Ti exceeds 0.50% by mass, the oxide in the weld metal becomes a Ti-Al-Si-Mn-Mg-based oxide and the solidification structure becomes finer and the hot cracking resistance is improved. Since the portion dissolves and lowers the solidification temperature of the weld metal, it exceeds the effect of improving the resistance to hot cracking by refining the solidified structure, and hot cracking is likely to occur. Therefore, the amount of Ti is desirably 0.05 to 0.50 mass%.

(Al:0.02〜0.10質量%)
Alは強脱酸剤であり溶接金属中に生成する介在物から、Alに比べ脱酸力の弱いSiからなるSiOやMnからなるMnOを還元し、介在物の組成を凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物組成の介在物に制御できる。その結果、溶接金属の高温割れ抑制作用が改善する。Al量が0.02質量%未満では、上記作用が充分でなく、高温割れが発生する。Al量が0.10質量%を超えると、溶接金属中の介在物からTi酸化物が還元され、Al主体となり、凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物組成に制御できなくなり、溶接金属に高温割れが発生する。よって、Al量は、0.02〜0.10質量%とすることが望ましい。
(Al: 0.02-0.10 mass%)
Al is a strong deoxidizer, and from the inclusions formed in the weld metal, SiO 2 composed of Si and MnO composed of Mn, which have a weaker deoxidation power than Al, are reduced, and the composition of the inclusions is refined to a solidified structure. It can be controlled to an inclusion of an effective Ti—Al—Si—Mn—Mg-based oxide composition. As a result, the hot metal cracking suppressing effect of the weld metal is improved. When the amount of Al is less than 0.02% by mass, the above action is not sufficient and hot cracking occurs. When the amount of Al exceeds 0.10% by mass, Ti oxide is reduced from inclusions in the weld metal, becomes mainly Al 2 O 3, and Ti—Al—Si—Mn—Mg is effective for refining the solidified structure. It becomes impossible to control the system oxide composition, and hot cracking occurs in the weld metal. Therefore, the Al content is desirably 0.02 to 0.10% by mass.

(O:0.03〜0.10質量%)
Oは溶接金属の凝固組織を微細化する酸化物を構成する元素であり、溶接金属の耐高温割れ性改善に寄与している。O量が0.03質量%未満では、酸化物量が不足し、凝固組織微細化効果が充分でなく、高温割れが発生する。O量が0.10質量%を超えると、酸化物の個数の増加および粗大化を招き、靭性が低下するため好ましくない。よって、O量は、0.03〜0.10質量%とすることが望ましい。
(O: 0.03-0.10 mass%)
O is an element constituting an oxide that refines the solidification structure of the weld metal, and contributes to the improvement of the hot crack resistance of the weld metal. When the amount of O is less than 0.03% by mass, the amount of oxide is insufficient, the effect of refining the solidified structure is not sufficient, and hot cracking occurs. If the amount of O exceeds 0.10% by mass, the number of oxides increases and becomes coarse, and the toughness decreases. Therefore, the amount of O is desirably 0.03 to 0.10% by mass.

(Mg:0.0002〜0.01質量%)
Mgは強脱酸元素であり、溶接金属中の介在物からMgに比べて脱酸力の弱いSiやMnからなる酸化物を還元し、溶接金属の凝固組織微細化に有効なTi−Al−Si−Mn−Mg系酸化物の制御を促進する。Mg量が0.0002質量%未満では、上記効果を生ずるには充分ではなく、高温割れが発生する。Mg量が0.01質量%を超えると、溶接金属中の介在物からTi酸化物が還元され、酸化物は凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物組成に制御できなくなり、溶接金属に高温割れが発生する。よって、Mg量は、0.0002〜0.01質量%とすることが望ましい。
(Mg: 0.0002 to 0.01% by mass)
Mg is a strong deoxidizing element, and Ti—Al— effective in reducing the solidification structure of the weld metal by reducing oxides of Si and Mn, which have a weaker deoxidation power than Mg, from inclusions in the weld metal. The control of the Si—Mn—Mg oxide is promoted. If the amount of Mg is less than 0.0002% by mass, it is not sufficient to produce the above effect, and hot cracking occurs. When the Mg content exceeds 0.01% by mass, Ti oxide is reduced from inclusions in the weld metal, and the oxide is an effective Ti-Al-Si-Mn-Mg-based oxide composition for refining the solidification structure. Therefore, it becomes impossible to control, and hot cracking occurs in the weld metal. Therefore, the amount of Mg is preferably 0.0002 to 0.01% by mass.

(P:0.03質量%以下)
Pは不純物元素であり、P量が0.03質量%を超えると、著しく耐高温割れ性が劣るため、P量は0.03質量%以下とすることが望ましい。
(P: 0.03 mass% or less)
P is an impurity element, and if the amount of P exceeds 0.03% by mass, the hot cracking resistance is remarkably inferior. Therefore, the amount of P is preferably 0.03% by mass or less.

(S:0.02質量%以下)
Sは不純物元素であり、S量が0.02質量%を超えると、著しく耐高温割れ性が劣るため、S量は0.02質量%以下とすることが望ましい。
(S: 0.02 mass% or less)
S is an impurity element. If the amount of S exceeds 0.02% by mass, the hot cracking resistance is remarkably deteriorated. Therefore, the amount of S is preferably 0.02% by mass or less.

(N:0.002〜0.01質量%)
Nは溶接金属の強度を確保する元素である。N量が0.002質量%未満では、溶接金属の強度が不足する。N量が0.01質量%を超えると、溶接金属中にブローホールが発生し、靭性も低下する。よって、N量は、0.002〜0.01質量%とすることが望ましい。
(N: 0.002 to 0.01% by mass)
N is an element that ensures the strength of the weld metal. If the N content is less than 0.002% by mass, the strength of the weld metal is insufficient. When the amount of N exceeds 0.01% by mass, blow holes are generated in the weld metal and the toughness is also lowered. Therefore, the N amount is desirably 0.002 to 0.01% by mass.

(B:0.0003〜0.005質量%)
Bはγ粒界に偏析し、初析フェライトの生成を抑制する効果があり、溶接金属の靭性改善に有効である。B量が0.0003質量%未満では、大部分のBがBNとして窒化物に固定化され、初析フェライトの生成を抑制する効果が無く、靭性が低下する。B量が0.005質量%を超えると、溶接金属の凝固温度を著しく低下させ、高温割れが発生しやすくなる。よって、B量は、0.0003〜0.005質量%とすることが望ましい。
(B: 0.0003 to 0.005 mass%)
B segregates at the γ grain boundary and has the effect of suppressing the formation of pro-eutectoid ferrite, which is effective in improving the toughness of the weld metal. When the amount of B is less than 0.0003 mass%, most of B is fixed to nitride as BN, and there is no effect of suppressing the formation of proeutectoid ferrite, resulting in a decrease in toughness. If the amount of B exceeds 0.005% by mass, the solidification temperature of the weld metal is remarkably lowered, and hot cracking tends to occur. Therefore, the amount of B is desirably 0.0003 to 0.005 mass%.

(Fe)
残部のFeは、ワイヤの鋼製外皮構成するFe、および/または、ワイヤのフラックスに添加されている鉄粉、合金粉のFe、および/または、母材のFeに相当する。
(Fe)
The remaining Fe corresponds to Fe constituting the steel outer sheath of the wire and / or iron powder added to the wire flux, Fe of alloy powder, and / or Fe of the base material.

(不可避的不純物)
残部の不可避的不純物としては、S、P、Ni、O、Zr等が挙げられ、本発明の効果を妨げない範囲で含有することが許容される。
(Inevitable impurities)
The remaining inevitable impurities include S, P, Ni, O, Zr and the like, and it is allowed to be contained within a range that does not hinder the effects of the present invention.

本発明に係る溶接金属は、さらに希土類元素の1種または2種以上を、合計0.01質量%以下含有してもよい。   The weld metal according to the present invention may further contain one or more rare earth elements in a total amount of 0.01% by mass or less.

(希土類元素:0.01質量%以下)
希土類元素は強脱酸元素であり、溶接金属中の介在物から希土類元素に比べて脱酸力の弱いSiやMnからなる酸化物を還元し、溶接金属の凝固組織微細化に有効なTi−Al−Si−Mn−Mg系酸化物制御を促進する。希土類元素が0.01質量%を超えると、溶接金属中の介在物からTi酸化物が還元され、酸化物は凝固組織微細化に効果的なTi−Al−Si−Mn−Mg系酸化物組成に制御できなくなり、溶接金属に高温割れが発生する。また、経済的にも0.01質量以下とすることが望ましい。本発明にいう希土類元素とは、Sc、Yおよび原子番号57(La)乃至71(Lu)をいう。なお、希土類元素の含有量は、後述のようにフラックス入りワイヤの組成を調整することによって制御することができる。
(Rare earth element: 0.01% by mass or less)
Rare earth element is a strong deoxidizing element, and it reduces Ti and Mn oxides, which have weaker deoxidizing power than inclusions in rare earth elements, from inclusions in the weld metal, and is effective for refining the solidification structure of weld metal. Promotes control of Al-Si-Mn-Mg oxides. When the rare earth element exceeds 0.01% by mass, the Ti oxide is reduced from inclusions in the weld metal, and the oxide is an effective Ti—Al—Si—Mn—Mg based oxide composition for refining the solidification structure. Therefore, it becomes impossible to control, and hot cracking occurs in the weld metal. Moreover, it is desirable also to set it as 0.01 mass or less economically. The rare earth element referred to in the present invention refers to Sc, Y and atomic numbers 57 (La) to 71 (Lu). The rare earth element content can be controlled by adjusting the composition of the flux-cored wire as will be described later.

本発明に係る溶接金属は、さらにCu、Ni、Cr、Mo、Nb、およびVからなる群から選択された少なくとも1種の元素を、合計0.5質量%以下含有してもよい。   The weld metal according to the present invention may further contain at least one element selected from the group consisting of Cu, Ni, Cr, Mo, Nb, and V in total of 0.5% by mass or less.

(Cu、Ni、Cr、Mo、Nb、V:0.5質量%以下)
本発明においては、溶接金属の強度および靭性を調整するために、Cu、Ni、Cr、Mo、Al、Nb、Vの少なくとも1種以上を、0.5質量%以下の範囲内であれば、含有してもよい。これらの元素は、上記範囲内の量であれば、溶接金属の凝固組織を微細化するために不可欠なTi−Al−Si−Mn−Mg系酸化物に影響を及ぼさない。なお、Cu、Ni、Cr、Mo、Al、Nb、Vの含有量は、後述のようにフラックス入りワイヤの組成を調整することによって制御することができる。
(Cu, Ni, Cr, Mo, Nb, V: 0.5% by mass or less)
In the present invention, in order to adjust the strength and toughness of the weld metal, at least one of Cu, Ni, Cr, Mo, Al, Nb, and V is within a range of 0.5% by mass or less. You may contain. These elements do not affect the Ti—Al—Si—Mn—Mg based oxide, which is indispensable for refining the solidification structure of the weld metal, as long as the amount is within the above range. The contents of Cu, Ni, Cr, Mo, Al, Nb, and V can be controlled by adjusting the composition of the flux-cored wire as will be described later.

(Ti−Al−Si−Mn−Mg系酸化物)
溶接金属に含まれる円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率は、Ti:30〜70原子%、Al:30〜70原子%、Si:15原子%以下(0原子%を含む)、Mn:15原子%以下(0原子%を含む)、Mg:10原子%以下(0原子%を含む)とする。なお、金属元素の比率は原子%であり、Ti+Al+Si+Mn+Mg=100原子%となる。Ti−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率が上記範囲内であれば、凝固組織のδフェライト組織の微細化に有効であり、溶接金属の耐高温割れ特性を著しく改善する。なお、Ti−Al−Si−Mn−Mg系酸化物の比率は、後述のようにフラックス入りワイヤの組成を調整することによって制御することができる。
(Ti-Al-Si-Mn-Mg-based oxide)
The ratio of the metal elements constituting the Ti-Al-Si-Mn-Mg-based oxide having a circle-equivalent diameter of 0.5 to 5.0 μm contained in the weld metal is Ti: 30 to 70 atomic%, Al: 30 to 30%. 70 atomic%, Si: 15 atomic% or less (including 0 atomic%), Mn: 15 atomic% or less (including 0 atomic%), Mg: 10 atomic% or less (including 0 atomic%). Note that the ratio of the metal element is atomic%, and Ti + Al + Si + Mn + Mg = 100 atomic%. If the ratio of the metal elements constituting the Ti-Al-Si-Mn-Mg-based oxide is within the above range, it is effective for refining the δ ferrite structure of the solidified structure and significantly improves the hot cracking resistance of the weld metal. Improve. Note that the ratio of the Ti—Al—Si—Mn—Mg oxide can be controlled by adjusting the composition of the flux-cored wire as described later.

Ti−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率(原子分率)と個数は、例えば、日本電子(株)製「JXA−8500F」を用い、溶接金属中央部の任意の測定領域(3mm×4mm)に含まれるすべての酸化物を、EPMA(Electron Probe Micro−Analysis)による元素分析を行って測定することができる。   The ratio (atomic fraction) and the number of metal elements constituting the Ti-Al-Si-Mn-Mg oxide are, for example, “JXA-8500F” manufactured by JEOL Ltd. All oxides included in the measurement region (3 mm × 4 mm) can be measured by performing elemental analysis using EPMA (Electron Probe Micro-Analysis).

Ti−Al−Si−Mn−Mg系酸化物は、前述した方法で酸化物を測定したとき、溶接金属中に10〜500個/mm存在していることが好ましい。酸化物個数が上記の下限を下回ると、凝固組織微細化効果が充分でなく高温割れが発生する場合がある。一方、酸化物個数が上記の上限を上回ると、破壊時のボイドの起点が過剰となり、靭性が低下する場合がある。 Ti-Al-Si-Mn-Mg-based oxides are preferably present at 10 to 500 / mm 2 in the weld metal when the oxide is measured by the method described above. When the number of oxides falls below the above lower limit, the effect of refining the solidified structure is not sufficient, and hot cracking may occur. On the other hand, if the number of oxides exceeds the above upper limit, the starting point of voids at the time of fracture may be excessive, and the toughness may be reduced.

次に、本発明に係る溶接金属の製造方法について説明する。
(溶接材料)
本発明に係る溶接金属は、溶接材料(フラックス入りワイヤ)の組成を以下のように適切に制御することによって得られる。更には、溶接電流、溶接電圧、ワイヤ突き出し長さ、溶接方法等の溶接条件を適切に制御することが好ましい。
Next, the manufacturing method of the weld metal which concerns on this invention is demonstrated.
(Welding material)
The weld metal according to the present invention can be obtained by appropriately controlling the composition of the welding material (flux-cored wire) as follows. Furthermore, it is preferable to appropriately control welding conditions such as a welding current, a welding voltage, a wire protrusion length, and a welding method.

フラックス入りワイヤの詳細な組成は、溶接条件等によっても相違するが、例えば、溶接効率に優れたガスシールドアーク溶接を用いて溶接する場合、所望の成分のTi−Al−Si−Mn−Mg系酸化物が得られるように、フラックス入りワイヤの組成を以下のように制御することが望ましい。すなわち、C:0.03〜0.08質量%、Si:0.10〜1.00質量%、Mn:2.40〜3.7質量%、Ti:0.15〜1.00質量%、TiO:5.0〜8.0質量%、Al:0.20〜0.50質量%、Al:0.05〜0.50質量%、B:0.003〜0.020質量%、P:0.03質量%以下、S:0.02質量%以下、N:0.002〜0.01質量%、Mg:0.3〜1.0質量%を含有し、残部がFeおよび不可避的不純物からなり、かつ、(4×Ti+10×Al−3×Si)≧1.0の関係式(前記関係式において(Ti)は、前記ワイヤに含有される前記Tiおよび前記TiOのうちの前記Tiのみから算出されるTi量である)を満足することが好ましい。なお、計算式(4×Ti+10×Al−3×Si)は、ワイヤに含まれるTi量を所定範囲内に制御するために、ワイヤに含まれるTi(TiOを含まない)量(質量%)を[Ti]とし、Al量を[Al]とし、Si量を[Si]として表したときに、経験的・実験的に得られた式である。 The detailed composition of the flux-cored wire differs depending on the welding conditions and the like. For example, when welding using gas shielded arc welding with excellent welding efficiency, the Ti-Al-Si-Mn-Mg system of the desired component is used. In order to obtain an oxide, it is desirable to control the composition of the flux-cored wire as follows. That is, C: 0.03-0.08 mass%, Si: 0.10-1.00 mass%, Mn: 2.40-3.7 mass%, Ti: 0.15-1.00 mass%, TiO 2: 5.0 to 8.0 mass%, Al: 0.20 to 0.50 wt%, Al 2 O 3: 0.05~0.50 wt%, B: 0.003~0.020 weight %, P: 0.03 mass% or less, S: 0.02 mass% or less, N: 0.002 to 0.01 mass%, Mg: 0.3 to 1.0 mass%, with the balance being Fe And (4 × Ti + 10 × Al−3 × Si) ≧ 1.0 relational expression (in the relational expression, (Ti) represents the Ti and TiO 2 contained in the wire). It is preferable that the amount of Ti calculated only from the Ti is satisfied. The calculation formula (4 × Ti + 10 × Al−3 × Si) is based on the amount of Ti (not including TiO 2 ) contained in the wire (mass%) in order to control the amount of Ti contained in the wire within a predetermined range. Is an expression obtained empirically and experimentally when [Ti] is represented as [Ti], the amount of Al is represented as [Al], and the amount of Si is represented as [Si].

フラックス入りワイヤは、さらに希土類元素の1種または2種以上を合計で0.500質量%以下含有することが好ましい。また、強度の更なる向上を目的として、Cr、Mo、Nb、およびVからなる群から選択された少なくとも1種の元素を0.5質量%以下含有することが好ましい。   The flux-cored wire preferably further contains one or more rare earth elements in a total amount of 0.500% by mass or less. For the purpose of further improving the strength, it is preferable to contain 0.5% by mass or less of at least one element selected from the group consisting of Cr, Mo, Nb, and V.

フラックス入りワイヤのフラックス充填率は、特に限定されず、ワイヤの生産性、例えば成型および伸線時の断線等を考慮して適宜設定することができる。フラックス充填率は、10〜25%の範囲内であることが好ましい。   The flux filling rate of the flux-cored wire is not particularly limited, and can be set as appropriate in consideration of the productivity of the wire, for example, disconnection at the time of molding and wire drawing. The flux filling factor is preferably in the range of 10 to 25%.

上記組成のフラックス入りワイヤの鋼製外皮は、特に限定されず、例えば、C:0.03質量%、Si:0.02質量%、Mn:0.25質量%、P:0.010質量%、S:0.007質量%を含有し、残部Feおよび不可避的不純物からなるものを使用することが好ましい。   The steel outer sheath of the flux-cored wire having the above composition is not particularly limited. For example, C: 0.03% by mass, Si: 0.02% by mass, Mn: 0.25% by mass, and P: 0.010% by mass. , S: It is preferable to use 0.007% by mass and comprising the remainder Fe and inevitable impurities.

フラックス入りワイヤの断面形状は特に限定されず、例えば、合わせ目はあっても無くても良い。なお、ワイヤの断面形状に合わせ目が無い場合には、ワイヤ送給性改善を目的として、ワイヤの表面にCuメッキ、Niメッキ、またはこれらの複合メッキを施しても良い。   The cross-sectional shape of the flux-cored wire is not particularly limited. For example, it may or may not have a joint. If there is no match in the cross-sectional shape of the wire, Cu plating, Ni plating, or a composite plating thereof may be applied to the surface of the wire for the purpose of improving wire feedability.

溶接母材の組成は特に限定されず、例えば、JIS G3106 SM400B鋼(C:0.12質量%、Si:0.2質量%、Mn:1.1質量%、P:0.008質量%、S:0.003質量%を含有し、残部Feおよび不可避的不純物)等を用いることができる。   The composition of the weld base material is not particularly limited. For example, JIS G3106 SM400B steel (C: 0.12% by mass, Si: 0.2% by mass, Mn: 1.1% by mass, P: 0.008% by mass, S: 0.003% by mass, and the balance Fe and inevitable impurities) can be used.

(溶接方法)
溶接方法に関しては、溶接効率等を考慮すると、ガスシールドアーク溶接を行うことが好ましい。なお、溶接金属の化学組成は、一般に、フラックス入りワイヤ等の溶接材料のほか、母材の希釈による影響等も受けるが、ガスシールドアーク溶接を行う場合には、その影響はほとんどない。
(Welding method)
Regarding the welding method, it is preferable to perform gas shielded arc welding in consideration of welding efficiency and the like. The chemical composition of the weld metal is generally affected by the dilution of the base material in addition to the welding material such as the flux-cored wire, but there is almost no influence when performing gas shielded arc welding.

ガスシールドアーク溶接の方法は、特に限定されず、通常用いられる方法を採用することができる。例えば、シールドガスとしては、100%COガスの他、ArガスとCOガスとの混合ガス、ArガスとOガスとの混合ガス、ArガスとCOガスとOガスとの3種類の混合ガス等が用いられる。 The method of gas shield arc welding is not particularly limited, and a commonly used method can be adopted. For example, as the shielding gas, in addition to 100% CO 2 gas, a mixed gas of Ar gas and CO 2 gas, a mixed gas of Ar gas and O 2 gas, Ar gas, CO 2 gas, and O 2 gas 3 A kind of mixed gas or the like is used.

ただし、本発明に用いられる溶接方法は、上記のみに限定されず、例えば、被覆アーク溶接法、ティグ溶接、サブマージアーク溶接法、ガスシールドアーク溶接法等のいずれの溶接法にも適用可能である。   However, the welding method used in the present invention is not limited to the above, and can be applied to any welding method such as a covering arc welding method, a TIG welding, a submerged arc welding method, and a gas shielded arc welding method. .

以下、実施例を挙げて本発明をより具体的に説明する。なお、本発明は下記実施例によって制限されず、本発明の趣旨に適合しうる範囲で適切に変更を加えて実施することも可能であり、それらは何れも本発明の技術的範囲に含まれる。   Hereinafter, the present invention will be described more specifically with reference to examples. It should be noted that the present invention is not limited by the following examples, and can be implemented with appropriate modifications within a range that can be adapted to the spirit of the present invention, all of which are included in the technical scope of the present invention. .

表1,2に示すフラックス入りワイヤを用い、JIS G3106 SM400B鋼(C:0.12質量%、Si:0.2質量%、Mn:1.1質量%、P:0.008質量%、S:0.003質量%を含有し、残部Feおよび不可避的不純物)からなる溶接母材を、表3に示す溶接条件で片面溶接(下向突合せ溶接)し、表4,5に示す化学組成を有する溶接金属を得た。   Using flux-cored wires shown in Tables 1 and 2, JIS G3106 SM400B steel (C: 0.12% by mass, Si: 0.2% by mass, Mn: 1.1% by mass, P: 0.008% by mass, S : A welding base material containing 0.003% by mass, the balance being Fe and inevitable impurities) is subjected to single-sided welding (downward butt welding) under the welding conditions shown in Table 3, and the chemical compositions shown in Tables 4 and 5 are obtained. A weld metal having was obtained.

なお、溶接金属成分の測定方法としては、C量およびS量は「燃焼赤外線吸収法」によって、N量およびO量は「不活性ガス融解熱伝導度法」によって、Si量、Mn量、Ti量、Al量、Mg量、B量、希土類元素量は「ICP発光分光分析法」によって、P量は「吸光光度法」によって測定した。なお、希土類元素はCe、Laを測定した。   In addition, as a measuring method of a weld metal component, C amount and S amount are determined by “combustion infrared absorption method”, N amount and O amount are determined by “inert gas fusion thermal conductivity method”, Si amount, Mn amount, Ti amount. The amount, Al amount, Mg amount, B amount, and rare earth element amount were measured by “ICP emission spectroscopic analysis”, and the P amount was measured by “absorption photometry”. The rare earth elements were Ce and La.

Figure 2011000626
Figure 2011000626

Figure 2011000626
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Figure 2011000626
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Figure 2011000626
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Figure 2011000626
Figure 2011000626

ここで、図1は、高温割れ抑制作用の評価に使用する溶接母材の開先形状を示す断面図である。図1に示すように、溶接母材1はV形状の開先を有し、このV形状の開先の裏面には、耐火物2およびアルミニウムテープ等からなる裏当て材3が配置されている。そして、開先角度を35°として、セラミック製の裏当て材が配置されている部分のルート間隔を4mmとした。   Here, FIG. 1 is a cross-sectional view showing a groove shape of a weld base material used for evaluation of a hot crack inhibiting action. As shown in FIG. 1, the welding base material 1 has a V-shaped groove, and a backing material 3 made of a refractory 2 and an aluminum tape is disposed on the back surface of the V-shaped groove. . The groove angle was set to 35 °, and the root interval of the portion where the ceramic backing material was disposed was set to 4 mm.

作製された溶接金属の酸化物形態を測定し、以下に示す方法で、高温割れ抑制作用、機械的性質(引張強さ、吸収エネルギー)について評価した。その評価結果に基づいて、実施例および比較例の溶接金属の総合評価を行った。   The oxide form of the produced weld metal was measured, and the hot crack inhibiting action and mechanical properties (tensile strength, absorbed energy) were evaluated by the following methods. Based on the evaluation results, comprehensive evaluation of the weld metals of the examples and comparative examples was performed.

(酸化物形態)
Ti−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率(原子分率)と個数は、日本電子(株)製「JXA−8500F」を用い、溶接金属中央部の任意の測定領域(3mm×4mm)に含まれるすべての酸化物を、EPMA(Electron Probe Micro−Analysis)による元素分析を行って測定した。その結果を表6,7に示す。
(Oxide form)
The ratio (atomic fraction) and the number of metal elements constituting the Ti-Al-Si-Mn-Mg-based oxide were measured arbitrarily using the "JXA-8500F" manufactured by JEOL Ltd. All oxides included in the region (3 mm × 4 mm) were measured by elemental analysis using EPMA (Electron Probe Micro-Analysis). The results are shown in Tables 6 and 7.

(耐高温割れ性)
溶接終了後、初層溶接部(クレータ部を除く)について、X線透過試験(JIS Z 3104)にて、内部割れの有無を確認し、割れ発生部分のトータル長さ測定し、割れ率を算出した。ここで、割れ率は、割れ率W=(割れ発生部分のトータル長さ)/(初層溶接部長さ(クレータ部を除く))×100により算出される。その割れ率で耐高温割れ性を評価した。その結果を表6,7に示す。
(High temperature crack resistance)
After welding, the first layer welded part (excluding the crater part) is checked for internal cracks in the X-ray transmission test (JIS Z 3104), the total length of the cracked part is measured, and the cracking rate is calculated. did. Here, the cracking rate is calculated by the cracking rate W = (total length of cracked portion) / (first layer welded portion length (excluding crater portion)) × 100. The hot crack resistance was evaluated based on the crack rate. The results are shown in Tables 6 and 7.

Figure 2011000626
Figure 2011000626

Figure 2011000626
Figure 2011000626

評価基準は以下の通りとした。
(耐高温割れ性)
割れ率5%以下のときを耐高温割れ性が良好とし、割れ率0%のときを耐高温割れ性が優れているとし、割れ率が5%を超えるときを不良とした。
The evaluation criteria were as follows.
(High temperature crack resistance)
When the cracking rate was 5% or less, the hot cracking resistance was good, when the cracking rate was 0%, the hot cracking resistance was excellent, and when the cracking rate exceeded 5%, it was regarded as defective.

(機械的性質)
JIS Z3313に準じて、引張強さ、0℃吸収エネルギー(靭性)について評価した。
引張強さの評価基準は、490MPa以上640MPa以下のときを良好とし、490MPa未満または640MPa超のときを不良とした。また、0℃吸収エネルギーの評価基準は、60J以上のときを良好とし、60J未満のときを不良とした。
(mechanical nature)
In accordance with JIS Z3313, tensile strength and 0 ° C. absorbed energy (toughness) were evaluated.
The evaluation standard of the tensile strength was good when it was 490 MPa or more and 640 MPa or less, and was poor when it was less than 490 MPa or more than 640 MPa. In addition, the evaluation standard of 0 ° C. absorbed energy was determined to be good when it was 60 J or more and poor when it was less than 60 J.

(総合評価)
総合評価の評価基準は、前記評価項目のうち、耐高温割れ性が優れており、機械的性質が良好であるときを、溶接金属としてより優れている:「◎」とし、耐高温割れ性が良好であり、機械的性質が良好であるときを、溶接金属として優れている:「○」とし、前記評価項目の少なくとも1つが不良であるときを、溶接金属として劣っている:「×」で示した。
(Comprehensive evaluation)
The evaluation criteria of the comprehensive evaluation are that, among the evaluation items, when the hot crack resistance is excellent and the mechanical properties are good, the weld metal is more excellent: “◎”, and the hot crack resistance is When it is good and mechanical properties are good, it is excellent as a weld metal: “◯”, and when at least one of the evaluation items is defective, it is inferior as a weld metal: “x” Indicated.

表4,6に示すように、実施例No.1〜22は、本発明の範囲を満足するため、耐高温割れ性、機械的性質の全てにおいて優れていた。特に、実施例No.20〜22は、希土類元素を添加することにより、耐高温割れ性が0%であった。   As shown in Tables 4 and 6, Example No. 1-22 were excellent in all of hot cracking resistance and mechanical properties in order to satisfy the scope of the present invention. In particular, Example No. Nos. 20 to 22 had a hot crack resistance of 0% by adding rare earth elements.

表5,7に示すように、比較例No.23は、C量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.24は、C量が下限値未満であるため、耐高温割れ性および機械的性質に劣っていた。比較例No.25は、Si量が上限値を超えるため、耐高温割れ性に劣っていた。   As shown in Tables 5 and 7, Comparative Example No. No. 23 was inferior in hot cracking resistance because the amount of C exceeded the upper limit. Comparative Example No. No. 24 was inferior in hot cracking resistance and mechanical properties because the C content was less than the lower limit. Comparative Example No. No. 25 was inferior in hot cracking resistance because the Si amount exceeded the upper limit.

比較例No.26は、Mn量が上限値を超え、酸化物も多くなったため、耐高温割れ性が劣っていた。比較例No.27は、Mn量が下限値未満であるため、耐高温割れ性に劣っていた。比較例No.28は、Ti量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.29は、Ti量が下限値未満であるため、耐高温割れ性に劣っていた。   Comparative Example No. In No. 26, the amount of Mn exceeded the upper limit value and the amount of oxides increased, so the hot crack resistance was poor. Comparative Example No. No. 27 was inferior in hot cracking resistance because the amount of Mn was less than the lower limit. Comparative Example No. No. 28 was inferior in hot cracking resistance because the Ti amount exceeded the upper limit. Comparative Example No. No. 29 was inferior in hot cracking resistance because the Ti amount was less than the lower limit.

比較例No.30は、Al量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.31は、Al量が下限値未満であるため、耐高温割れ性に劣っていた。比較例No.32は、O量が上限値を超えるため、機械的性質に劣っていた。比較例No.33は、O量が下限値未満であるため、耐高温割れ性に劣っていた。   Comparative Example No. No. 30 was inferior in hot cracking resistance because the Al amount exceeded the upper limit. Comparative Example No. No. 31 was inferior in hot cracking resistance because the Al content was less than the lower limit. Comparative Example No. No. 32 was inferior in mechanical properties because the amount of O exceeded the upper limit. Comparative Example No. No. 33 was inferior in hot cracking resistance because the amount of O was less than the lower limit.

比較例No.34は、Mg量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.35は、Mg量が下限値未満であるため、耐高温割れ性に劣っていた。比較例No.36は、P量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.37は、S量が上限値を超えるため、耐高温割れ性に劣っていた。   Comparative Example No. No. 34 was inferior in hot cracking resistance because the amount of Mg exceeded the upper limit. Comparative Example No. No. 35 was inferior in hot cracking resistance because the amount of Mg was less than the lower limit. Comparative Example No. No. 36 was inferior in hot cracking resistance because the P amount exceeded the upper limit. Comparative Example No. No. 37 was inferior in hot cracking resistance because the S amount exceeded the upper limit.

比較例No.38は、N量が上限値を超えるため、機械的性質に劣っていた。比較例No.39は、N量が下限値未満であるため、機械的性質に劣っていた。比較例No.40は、B量が上限値を超えるため、耐高温割れ性に劣っていた。比較例No.41は、B量が下限値未満であるため、機械的性質に劣っていた。比較例No.42は、希土類元素量が上限値を超えるため、耐高温割れ性に劣っていた。   Comparative Example No. No. 38 was inferior in mechanical properties because the N amount exceeded the upper limit. Comparative Example No. No. 39 was inferior in mechanical properties because the N amount was less than the lower limit. Comparative Example No. No. 40 was inferior in hot cracking resistance because the B amount exceeded the upper limit. Comparative Example No. No. 41 was inferior in mechanical properties because the amount of B was less than the lower limit. Comparative Example No. No. 42 was inferior in hot cracking resistance because the amount of rare earth elements exceeded the upper limit.

以上の結果から、実施例No.1〜22は、比較例No.23〜42と比べて、溶接金属として優れていることが確認された。   From the above results, Example No. 1-22 are comparative example No.1. Compared with 23-42, it was confirmed that it is excellent as a weld metal.

1 溶接母材
2 耐火物
3 裏当て材
1 Welding base material 2 Refractory 3 Backing material

Claims (3)

鋼製外皮内にフラックスが充填されたフラックス入りワイヤにより溶接された溶接金属であって、
C:0.01〜0.10質量%、Si:0.7質量%以下、Mn:0.5〜3.0質量%、Ti:0.05〜0.50質量%、Al:0.02〜0.10質量%、O:0.03〜0.10質量%、Mg:0.0002〜0.01質量%、P:0.03質量%以下、S:0.02質量%以下、N:0.002〜0.01質量%、B:0.0003〜0.005質量%、を含有し、残部がFeおよび不可避的不純物からなり、
かつ、前記溶接金属に含まれる円相当直径が0.5〜5.0μmのTi−Al−Si−Mn−Mg系酸化物を構成する金属元素の比率が、Ti:30〜70原子%、Al:30〜70原子%、Si:15原子%以下(0原子%を含む)、Mn:15原子%以下(0原子%を含む)、Mg:10原子%以下(0原子%を含む)、の範囲内である(ただし、Ti+Al+Si+Mn+Mg=100原子%とする)ことを特徴とする溶接金属。
A weld metal welded by a flux-cored wire filled with a flux in a steel outer shell,
C: 0.01-0.10 mass%, Si: 0.7 mass% or less, Mn: 0.5-3.0 mass%, Ti: 0.05-0.50 mass%, Al: 0.02 -0.10 mass%, O: 0.03-0.10 mass%, Mg: 0.0002-0.01 mass%, P: 0.03 mass% or less, S: 0.02 mass% or less, N : 0.002-0.01% by mass, B: 0.0003-0.005% by mass, with the balance being Fe and inevitable impurities,
And the ratio of the metal element which comprises the Ti-Al-Si-Mn-Mg type | system | group oxide whose circle equivalent diameter contained in the said weld metal is 0.5-5.0 micrometers is Ti: 30-70 atomic%, Al : 30-70 atomic%, Si: 15 atomic% or less (including 0 atomic%), Mn: 15 atomic% or less (including 0 atomic%), Mg: 10 atomic% or less (including 0 atomic%) A weld metal characterized by being in the range (provided that Ti + Al + Si + Mn + Mg = 100 atomic%).
希土類元素の1種または2種以上を、合計0.01質量%以下含有することを特徴とする請求項1に記載の溶接金属。   The weld metal according to claim 1, wherein the weld metal contains one or more rare earth elements in a total of 0.01% by mass or less. Cu、Ni、Cr、Mo、Nb、およびVからなる群から選択された少なくとも1種の元素を、合計0.5質量%以下含有することを特徴とする請求項1または2に記載の溶接金属。   The weld metal according to claim 1 or 2, comprising at least one element selected from the group consisting of Cu, Ni, Cr, Mo, Nb, and V in total of 0.5% by mass or less. .
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* Cited by examiner, † Cited by third party
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US20160008906A1 (en) * 2013-02-15 2016-01-14 Nippon Steel & Sumitomo Metal Corporation Solid wire for gas shielded arc welding, weld metal by gas shielded arc welding, welded joint, weldment, welding method, and production method of welded joint
JP2018034170A (en) * 2016-08-29 2018-03-08 日鐵住金溶接工業株式会社 Flux-cored wire for gas shielded arc welding

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JP2001254141A (en) * 2000-03-09 2001-09-18 Kobe Steel Ltd Weld metal excellent in thougness
JP2009028764A (en) * 2007-07-27 2009-02-12 Kobe Steel Ltd Weld metal and titania-based flux cored wire
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012137957A1 (en) * 2011-04-08 2012-10-11 株式会社神戸製鋼所 Weld metal having excellent resistance to hydrogen embrittlement
JP2012218034A (en) * 2011-04-08 2012-11-12 Kobe Steel Ltd Weld metal having excellent resistance to hydrogen embrittlement
EP2695702A1 (en) * 2011-04-08 2014-02-12 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Weld metal having excellent resistance to hydrogen embrittlement
US20140086786A1 (en) * 2011-04-08 2014-03-27 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Weld metal having excellent resistance to hydrogen embrittlement susceptibility
EP2695702A4 (en) * 2011-04-08 2014-08-27 Kobe Steel Ltd Weld metal having excellent resistance to hydrogen embrittlement
KR101503634B1 (en) 2011-04-08 2015-03-18 가부시키가이샤 고베 세이코쇼 Weld metal having excellent resistance to hydrogen embrittlement
US9592575B2 (en) 2011-04-08 2017-03-14 Kobe Steel, Ltd. Weld metal having excellent resistance to hydrogen embrittlement susceptibility
US20160008906A1 (en) * 2013-02-15 2016-01-14 Nippon Steel & Sumitomo Metal Corporation Solid wire for gas shielded arc welding, weld metal by gas shielded arc welding, welded joint, weldment, welding method, and production method of welded joint
JP2018034170A (en) * 2016-08-29 2018-03-08 日鐵住金溶接工業株式会社 Flux-cored wire for gas shielded arc welding

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