JP2012051030A - Narrow groove butt welding method for thick steel sheet - Google Patents
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Abstract
Description
本発明は、ガスシールドアーク溶接法で厚鋼板の狭開先突合せ溶接を行なう溶接方法に関し、特に多層溶接にて安定した溶け込みが得られる狭開先突合せ溶接に関する。 The present invention relates to a welding method for performing narrow groove butt welding of thick steel plates by gas shielded arc welding, and more particularly to narrow groove butt welding in which stable penetration can be obtained by multilayer welding.
アーク点をガスでシールドして溶接を行なうガスシールドアーク溶接法は、能率の良い溶接法であるので、鉄鋼材料の溶接に広く利用されている。特に自動溶接の急速な普及によって、造船，建築，橋梁，自動車等の種々の分野で使用されている。造船，建築，橋梁の分野では、厚鋼板の多層溶接や隅肉溶接に使用され、自動車の分野では薄鋼板の隅肉溶接に使用されることが多い。 The gas shielded arc welding method, in which the arc point is shielded with gas and is welded, is a highly efficient welding method and is widely used for welding steel materials. In particular, due to the rapid spread of automatic welding, it is used in various fields such as shipbuilding, architecture, bridges, and automobiles. In the fields of shipbuilding, construction, and bridges, it is often used for multilayer welding and fillet welding of thick steel plates, and in the field of automobiles it is often used for fillet welding of thin steel plates.
ガスシールドアーク溶接は、アーク点をシールドするガス（以下、シールドガスという）の種類に応じて、
(A) Ar−２〜40体積％ＣＯ2 の混合ガスをシールドガスとして使用する混合ガスシールドアーク溶接法（いわゆるＭＡＧ溶接法）
(B) ＣＯ2 を主成分とする（すなわち50体積％以上含有する）炭酸ガスシールドアーク溶接法
等に分類される。
In gas shielded arc welding, depending on the type of gas that shields the arc point (hereinafter referred to as shielding gas),
(A) a mixed gas of Ar-2 to 40 mixed gas volume% CO 2 for use as a shielding gas shielded arc welding (so-called MAG welding method)
(B) It is classified into a carbon dioxide shielded arc welding method mainly containing CO 2 (that is, containing 50% by volume or more).
ＭＡＧ溶接法は、アークの安定性が優れているので平板上では深い溶け込みが得られる。しかしアークが拡がりやすいので、狭い開先の中ではアーク点が開先の壁面を這い上がる。その結果、狭開先突合せ溶接では、溶接ビードに凹凸（いわゆるハンピング）が生じ、開先底部の溶け込みが全く得られない。
炭酸ガスシールドアーク溶接法は、ＭＡＧ溶接法に比べて10〜20倍の粗大な溶滴が溶接ワイヤの先端に懸垂し、アーク力によって揺れ動きながら溶接ワイヤから鋼板に移行する現象（いわゆるグロビュール移行）が生じやすい。その結果、溶接ワイヤと鋼板との短絡や再アークによってスパッタが多量に発生するばかりでなく、アークが不安定になり、十分な溶け込みが得られない。
Since the MAG welding method has excellent arc stability, deep penetration can be obtained on a flat plate. However, since the arc tends to spread, the arc point crawls up the wall surface of the groove in a narrow groove. As a result, in narrow groove butt welding, unevenness (so-called humping) occurs in the weld bead, and no penetration of the groove bottom is obtained.
Carbon dioxide shielded arc welding is a phenomenon in which coarse droplets that are 10 to 20 times larger than MAG welding hang from the tip of the welding wire and move from the welding wire to the steel plate while swaying by the arc force (so-called globule transition). Is likely to occur. As a result, not only a large amount of spatter is generated due to a short circuit or re-arcing between the welding wire and the steel plate, but the arc becomes unstable and sufficient penetration cannot be obtained.
また、ガスシールドアーク溶接で使用される消耗電極（すなわち溶接ワイヤ）は、ソリッドワイヤとフラックスコアードワイヤに大別される。
ソリッドワイヤは、鋼素線からなる溶接ワイヤであり、素材となる鋼素線の表面にめっきを施したり、あるいは潤滑剤を塗布したものもある。このソリッドワイヤは、ガスシールドアーク溶接によって優れた強度と靭性を持つ溶接金属が得られるので、主に突合せ溶接に使用される。一方、フラックスコアードワイヤ（以下、ＦＣワイヤという）は、鋼製の外殻の内側に溶接用フラックスを充填した溶接ワイヤであり、優れたビード形状が得られるので、主に隅肉溶接に使用される。
Further, consumable electrodes (that is, welding wires) used in gas shielded arc welding are roughly classified into solid wires and flux cored wires.
The solid wire is a welding wire made of a steel wire, and there is a wire in which the surface of a steel wire that is a material is plated or a lubricant is applied. This solid wire is mainly used for butt welding because a weld metal having excellent strength and toughness can be obtained by gas shielded arc welding. On the other hand, flux cored wire (hereinafter referred to as FC wire) is a welding wire in which a welding flux is filled inside a steel outer shell, and because it has an excellent bead shape, it is mainly used for fillet welding. Is done.
ＦＣワイヤがビード形状に優れる理由は、溶接ワイヤの先端から鋼板の溶融メタルに移行する溶滴が細かいので、溶融メタルの表面揺動が小さく抑えられ、かつ溶接用フラックスに多量に含まれるスラグ形成剤によって生成したスラグがビードを覆うからである。
ソリッドワイヤでは、溶接ワイヤの先端から鋼板の溶融メタルに移行する溶滴が粗くかつ移行が不規則であるから、溶融メタルの表面揺動が大きく、鋼素線に含有される脱酸元素（すなわちSi，Mn，Ti，Zr，Al等）の酸化によってスラグが形成される。その結果、スラグが不均一に分布し、ビードを完全に覆うには至らない。また、ソリッドワイヤを使用したガスシールドアーク溶接では、スラグがビードの端部に集積する。したがって、厚鋼板の突合せ溶接のような狭開先で多層溶接をガスシールドアーク溶接法で行なう場合にソリッドワイヤを使用すると、不均一に分布するスラグの影響でアークが不安定になり、溶接施工性が損なわれる。
The reason why the FC wire has an excellent bead shape is that the droplets that move from the tip of the welding wire to the molten metal of the steel sheet are fine, so that the surface fluctuation of the molten metal is kept small and slag is included in the welding flux in a large amount This is because the slag generated by the agent covers the bead.
In a solid wire, since the droplets transferred from the tip of the welding wire to the molten metal of the steel sheet are rough and irregular, the surface fluctuation of the molten metal is large and the deoxidizing element contained in the steel wire (ie, Slag is formed by oxidation of Si, Mn, Ti, Zr, Al, etc.). As a result, the slag is unevenly distributed and does not completely cover the bead. In gas shielded arc welding using a solid wire, slag accumulates at the end of the bead. Therefore, if a solid wire is used when performing multi-layer welding with narrow gaps such as butt welding of thick steel plates using the gas shielded arc welding method, the arc becomes unstable due to the influence of unevenly distributed slag, and welding work is performed. Sexuality is impaired.
そこで、ソリッドワイヤをガスシールドアーク溶接で使用する場合に生じる粗大な溶滴の不規則な移行を防止し、アークを安定化するために、種々の技術が検討されている。たとえば特許文献１には、溶接ワイヤに希土類元素（以下、REM という）を添加することによって、炭酸ガスシールドアーク溶接における溶滴を微細化する技術が開示されている。特許文献１に開示された溶接ワイヤはソリッドワイヤであるが、特許文献１には溶接ワイヤの極性に関する記載はない。
Therefore, various techniques have been studied in order to prevent irregular migration of coarse droplets that occur when a solid wire is used in gas shielded arc welding and stabilize the arc. For example,
一般に正極性（すなわち溶接ワイヤをマイナス極）では、鋼板の発熱量が少なく、溶け込みが浅くなるので、オーバーラップに起因する溶接欠陥が発生しやすく、ビード形状も安定しない。したがって溶接技術者は、溶接ワイヤを正極性で使用することは考慮せず、逆極性（すなわち溶接ワイヤをプラス極）で使用する。したがって特許文献１に開示された技術は、逆極性のガスシールドアーク溶接に適用するために検討された技術である。したがって特許文献１に開示されたガスシールドアーク溶接の技術を、ソリッドワイヤを用いた多層溶接に応用すると、優れたアーク安定性は得られない。
Generally, in the case of positive polarity (that is, the welding wire is a negative electrode), the amount of heat generated by the steel sheet is small, and the penetration becomes shallow. Therefore, a welding engineer does not consider using a welding wire with positive polarity, but uses it with a reverse polarity (ie, a welding wire with a positive polarity). Therefore, the technique disclosed in
本発明者らは、溶接ワイヤに REMを添加し、正極性で使用する技術を既に開発している（特許文献２，３参照）。これらの技術は、いずれも250Ａ以下の溶接電流で薄鋼板の溶接を行なう低電流溶接を対象としている。 The present inventors have already developed a technique of adding REM to a welding wire and using it with positive polarity (see Patent Documents 2 and 3). All of these techniques are directed to low current welding in which thin steel sheets are welded at a welding current of 250 A or less.
本発明は上記のような問題を解消し、ガスシールドアーク溶接法で厚鋼板の狭開先突合せ溶接を行なうにあたって、多層溶接の初層（すなわち開先の底部）においてもアークの安定性に優れ、安定した溶け込みが得られる溶接方法を提供することを目的とする。
なお、ここで鋼素線からなるガスシールドアーク溶接用鋼ワイヤとは、溶接用フラックスを内装せず、素材となる鋼素線を主体とするワイヤ（いわゆるソリッドワイヤ）を指す。また本発明は、鋼素線の表面にめっきを施したり、あるいは潤滑剤を塗布したガスシールドアーク溶接用鋼ワイヤにも支障なく適用できる。
The present invention solves the above-mentioned problems and is excellent in arc stability even in the first layer of multilayer welding (ie, the bottom of the groove) when performing narrow groove butt welding of thick steel plates by gas shielded arc welding. An object of the present invention is to provide a welding method capable of obtaining stable penetration.
In addition, the steel wire for gas shielded arc welding which consists of a steel strand here refers to the wire (what is called a solid wire) which does not incorporate the welding flux, and mainly has the steel strand used as a raw material. Further, the present invention can be applied without any trouble to a steel wire for gas shield arc welding in which the surface of a steel element wire is plated or a lubricant is applied.
本発明者らは、溶接用フラックスを内装していないソリッドワイヤと呼ばれるガスシールドアーク溶接用鋼ワイヤ（以下、溶接用鋼ワイヤという）を用いた多層ガスシールドアーク溶接について、狭開先突合せ溶接におけるアークを安定させる観点から鋭意検討した。従来は主に溶接用鋼ワイヤの素材となる鋼素線のＣ，Si，Mn，Ｐ，Ｓの添加量が主要な検討課題であったが、本発明者らは視点を変えて、初層（すなわち開先底部）の溶接条件，シールドガスの成分，溶接時の溶接用鋼ワイヤの極性，開先の形状が、アークの安定性に及ぼす影響について詳細に検討し、以下に述べる知見を得た。 In the narrow gap butt welding, multi-layer gas shielded arc welding using a steel wire for gas shielded arc welding (hereinafter referred to as a steel wire for welding) called a solid wire that does not include a welding flux is provided. From the viewpoint of stabilizing the arc, intensive studies were conducted. In the past, the amount of addition of C, Si, Mn, P, and S in the steel wire, which is mainly the material of the steel wire for welding, has been the main examination subject. We examined in detail the effects of welding conditions (that is, the bottom of the groove), the composition of the shielding gas, the polarity of the welding steel wire during welding, and the shape of the groove on the stability of the arc, and obtained the following knowledge It was.
(a) 溶接用鋼ワイヤの鋼素線に REMを添加し、かつ多層溶接における初層の溶接条件から下記の (1)，(2) 式で算出される指標ＱＬ値，ＱＨ値を調整することによって、アークの安定性が向上し、安定した溶け込みが得られる。
ＱＬ＝Ｉ×Ｅ／〔Ｓ×（Ｇ＋５× tanθ）〕／60 ・・・ (1)
ＱＨ＝〔Ｇ×Ｓ×60×（Ｇ＋ tanθ）／（Ｉ×Ｅ）〕＋ tanθ ・・・ (2)
Ｉ：溶接電流（Ａ）
Ｅ：溶接電圧（Ｖ）
Ｓ：溶接速度（mm／sec ）
θ：開先角度（°）
Ｇ：ルートギャップ（mm）
(b) シールドガスに含まれるＣＯ2 量を調整することによって、アークの安定性が一層向上し、安定した溶け込みが得られる。
(a) REM is added to the steel wire of the steel wire for welding, and the index QL and QH values calculated by the following formulas (1) and (2) are adjusted from the welding conditions of the first layer in multilayer welding As a result, the stability of the arc is improved and a stable penetration is obtained.
QL = I × E / [S × (G + 5 × tan θ)] / 60 (1)
QH = [G × S × 60 × (G + tan θ) / (I × E)] + tan θ (2)
I: Welding current (A)
E: Welding voltage (V)
S: Welding speed (mm / sec)
θ: groove angle (°)
G: Route gap (mm)
(b) By adjusting the amount of CO 2 contained in the shielding gas, the stability of the arc is further improved, and stable penetration can be obtained.
(c) 溶接時の溶接用鋼ワイヤの極性を適正に選択することによって、アークの安定性が一層向上し、安定した溶け込みが得られる。
(d) 開先形状を適正に設定することによって、アークの安定性が一層向上し、安定した溶け込みが得られる。
本発明は、これらの知見に基づいてなされたものである。
(c) By appropriately selecting the polarity of the welding steel wire at the time of welding, the stability of the arc is further improved and stable penetration can be obtained.
(d) By appropriately setting the groove shape, the stability of the arc is further improved and stable penetration can be obtained.
The present invention has been made based on these findings.
すなわち本発明は、希土類元素を0.015〜0.100質量％含有する鋼素線からなる溶接用鋼ワイヤを用いて、厚鋼板の多層ガスシールドアーク溶接を行なう狭開先突合せ溶接方法において、板厚12mm以上の厚鋼板を使用し、ルートギャップを２mm以下かつ開先角度を30°以下の狭開先とし、該狭開先の底部における初層のガスシールドアーク溶接を、溶接速度を15〜25mm／secとするとともに上記の(1)式で算出されるＱＬ値が1.5〜10.0の範囲内を満足しかつ上記の (2)式で算出されるＱＨ値が1.0以上の範囲内を満足する条件で行なって前記狭開先底部における深い溶け込みを得る狭開先突合せ溶接方法である。 That is, the present invention is a narrow groove butt welding method for performing multilayer gas shielded arc welding of a thick steel plate using a welding steel wire made of a steel wire containing 0.015 to 0.100% by mass of a rare earth element. The first layer of gas shielded arc welding at the bottom of the narrow groove with a root gap of 2 mm or less and a groove angle of 30 ° or less is used, and the welding speed is 15 to 25 mm / sec. And the condition that the QL value calculated by the above equation (1) satisfies the range of 1.5 to 10.0 and the QH value calculated by the above equation (2) satisfies the range of 1.0 or more. This is a narrow groove butt welding method for obtaining deep penetration at the bottom of the narrow groove.
本発明の狭開先突合せ溶接方法においては、初層のガスシールドアーク溶接を行なうにあたって、ＣＯ2 を50体積％以上含有するシールドガスを用いることが好ましい。また、初層のガスシールドアーク溶接を正極性で行なうことが好ましい。 In the narrow groove butt welding method of the present invention, it is preferable to use a shield gas containing 50% by volume or more of CO 2 when performing gas shield arc welding of the first layer. Moreover, it is preferable to perform gas shield arc welding of the first layer with positive polarity.
本発明によれば、ガスシールドアーク溶接法で厚鋼板の狭開先突合せ溶接を行なうにあたって、多層溶接の初層（すなわち開先の底部）においてもアークの安定性に優れ、安定した溶け込みが得られるので、狭開先突合せ溶接に有利であり、産業上格段の効果を奏する。 According to the present invention, when performing narrow gap butt welding of thick steel plates by gas shielded arc welding, excellent arc stability is obtained even in the first layer of multilayer welding (that is, the bottom of the groove), and stable penetration is obtained. Therefore, it is advantageous for narrow groove butt welding and has a remarkable industrial effect.
本発明の溶接用鋼ワイヤは、ソリッドワイヤとＦＣワイヤに大別される溶接ワイヤのうち、ソリッドワイヤを対象とする。
まず本発明の溶接用鋼ワイヤの鋼素線の成分を限定した理由について説明する。
REM：0.015〜0.100質量％
REMは、溶接金属の介在物微細化により靭性改善と高温割れ（凝固割れ）防止に有用な元素である。また、正極性のガスシールドアーク溶接においては、アーク集中による深い溶け込みを得るのに不可欠な元素である。特に、多層炭酸ガスシールドアーク溶接においては、アークの集中による深い溶け込みによってスラグ巻き込みやアンダーカットといった溶接欠陥の発生を抑制する働きがある。REM 含有量が0.015質量％未満では深い溶け込みによる溶接欠陥の発生を抑制する効果が得られない。一方、0.100質量％を超えて添加すると溶接用鋼ワイヤの製造工程で割れが生じたり、溶接金属の靭性低下を招く。したがって、REMは0.015〜0.100質量％の範囲を満足する必要がある。なお好ましくは0.025〜0.050質量％である。
The steel wire for welding according to the present invention is a solid wire among welding wires roughly classified into a solid wire and an FC wire.
First, the reason for limiting the components of the steel wire of the welding steel wire of the present invention will be described.
REM: 0.015-0.100 mass%
REM is an element useful for improving toughness and preventing high-temperature cracking (solidification cracking) by minimizing inclusions in the weld metal. Further, in positive gas shielded arc welding, it is an indispensable element for obtaining deep penetration due to arc concentration. In particular, in multilayer carbon dioxide shielded arc welding, there is a function of suppressing the occurrence of welding defects such as slag entrainment and undercut by deep penetration due to arc concentration. If the REM content is less than 0.015% by mass, the effect of suppressing the occurrence of weld defects due to deep penetration cannot be obtained. On the other hand, if added over 0.100% by mass, cracks occur in the manufacturing process of the welding steel wire, and the toughness of the weld metal is reduced. Therefore, REM needs to satisfy the range of 0.015-0.100 mass%. In addition, Preferably it is 0.025-0.050 mass%.
狭開先の多層ガスシールドアーク溶接では、アークを集中させて深い溶け込みを得る必要がある。従来は狭開先の溶接施工を行なう場合は、Si−Mn−Ti系の溶接用鋼ワイヤを用いて逆極性でガスシールドアーク溶接を行なっていた。しかし、そのような従来の技術では、十分な深さの溶け込みが得られず、スラグを巻き込む恐れがあった。そのため開先角度は35°程度，ルートギャップは８mm程度の溶接施工が最適とされていた。 In narrow gap multi-layer gas shielded arc welding, it is necessary to concentrate the arc to obtain deep penetration. Conventionally, when performing narrow groove welding, gas shielded arc welding was performed with a reverse polarity using a steel wire for Si-Mn-Ti welding. However, such a conventional technique cannot obtain a sufficient depth of penetration and may cause slag to be involved. Therefore, welding with a groove angle of about 35 ° and a root gap of about 8mm was considered optimal.
本発明では鋼素線に REMを添加し、さらに後述するように初層の溶接条件を所定の範囲に調整してガスシールドアーク溶接を行なう。その結果、開先底部における溶滴移行を安定させかつアークを集中させることによって、深い溶け込みが得られる。
ここで REMとは、周期表の３族に属する元素の総称である。本発明では、原子番号57〜71の元素を使用するのが好ましく、特にCe，Laが好適である。Ce，Laを鋼素線に添加する場合は、CeまたはLaを単独で添加しても良いし、CeおよびLaを併用しても良い。なお、CeおよびLaをともに添加する場合は、あらかじめCe：40〜90質量％，La：10〜60質量％の範囲内で混合して得られた混合物を使用するのが好ましい。
In the present invention, gas shielded arc welding is performed by adding REM to the steel wire and further adjusting the welding condition of the first layer within a predetermined range as described later. As a result, deep penetration is obtained by stabilizing the droplet transfer at the groove bottom and concentrating the arc.
Here, REM is a general term for elements belonging to Group 3 of the periodic table. In the present invention, it is preferable to use an element having an atomic number of 57 to 71, and Ce and La are particularly preferable. When Ce and La are added to the steel strand, Ce or La may be added alone, or Ce and La may be used in combination. In addition, when adding both Ce and La, it is preferable to use the mixture obtained by mixing beforehand in the range of Ce: 40-90 mass% and La: 10-60 mass%.
なお本発明は、基本的成分としてＣ，Si，Mn，Ｐ，Ｓを下記の通り含有する鋼素線からなる溶接用鋼ワイヤに適用するのが好ましい。
Ｃ：0.20質量％以下
Ｃは、溶接金属の強度を確保するのに必要な元素であり、溶融メタルの粘性を低下させて流動性を向上させる効果がある。しかしＣ含有量が0.20質量％を超えると、正極性の溶接において溶滴および溶融メタルの挙動が不安定となるのみならず、溶接金属の靭性の低下を招く。したがって、Ｃは0.20質量％以下が好ましい。一方、Ｃ含有量を過剰に減少させると溶接金属の強度を確保できない。そのため、0.003〜0.20質量％とするのが一層好ましい。なお、0.01〜0.10質量％がさらに好ましい。
In addition, it is preferable to apply this invention to the steel wire for welding which consists of a steel strand which contains C, Si, Mn, P, and S as a basic component as follows.
C: 0.20 mass% or less C is an element necessary for ensuring the strength of the weld metal, and has the effect of reducing the viscosity of the molten metal and improving the fluidity. However, if the C content exceeds 0.20% by mass, not only the behavior of droplets and molten metal becomes unstable in positive polarity welding, but also the toughness of the weld metal is reduced. Therefore, C is preferably 0.20% by mass or less. On the other hand, if the C content is excessively reduced, the strength of the weld metal cannot be ensured. Therefore, it is more preferable to set it as 0.003-0.20 mass%. In addition, 0.01-0.10 mass% is more preferable.
Si：0.05〜2.5質量％
Siは、脱酸作用を有し、溶融メタルの脱酸のためには不可欠な元素である。ガスシールドアーク溶接では、Si含有量が0.05質量％未満では、溶融メタルの脱酸が不足し、溶接金属にブローホールが発生する。さらに正極性のガスシールドアーク溶接におけるアークの広がりを抑え、溶滴を微細化し挙動を安定化する作用も有する。一方、2.5質量％を超えると、溶接金属の靭性が著しく低下する。したがって、Siは0.05〜2.5質量％の範囲内が好ましい。ただしSi含有量が0.65質量％を超えると、小粒のスパッタが増加する傾向が現われるので、0.05〜0.65質量％の範囲内が一層好ましい。
Si: 0.05-2.5 mass%
Si has a deoxidizing action and is an indispensable element for deoxidizing molten metal. In gas shielded arc welding, if the Si content is less than 0.05% by mass, deoxidation of the molten metal is insufficient and blowholes are generated in the weld metal. Furthermore, it has the effect of suppressing the spread of the arc in the positive polarity gas shielded arc welding, miniaturizing the droplets and stabilizing the behavior. On the other hand, if it exceeds 2.5 mass%, the toughness of the weld metal is significantly reduced. Therefore, Si is preferably within the range of 0.05 to 2.5% by mass. However, if the Si content exceeds 0.65% by mass, a tendency to increase the spatter of small grains appears, so that the range of 0.05 to 0.65% by mass is more preferable.
Mn：0.25〜3.5質量％
Mnは、Siと同様に脱酸作用を有し、溶融メタルの脱酸のためには不可欠な元素である。Mn含有量が0.25質量％未満では、溶融メタルの脱酸が不足し、溶接金属にブローホールが発生する。一方、3.5質量％を超えると、溶接金属の靭性が低下する。したがって、Mnは0.25〜3.5質量％の範囲内が好ましい。なお、溶融メタルの脱酸を促進し、ブローホールを防止するためには、0.45質量％以上が望ましい。そのため、0.45〜3.5質量％とするのが一層好ましい。
Mn: 0.25 to 3.5% by mass
Mn has a deoxidizing action similar to Si and is an indispensable element for deoxidizing molten metal. When the Mn content is less than 0.25% by mass, deoxidation of the molten metal is insufficient, and blow holes are generated in the weld metal. On the other hand, if it exceeds 3.5% by mass, the toughness of the weld metal decreases. Therefore, Mn is preferably in the range of 0.25 to 3.5% by mass. In order to promote deoxidation of molten metal and prevent blowholes, 0.45% by mass or more is desirable. Therefore, it is more preferable to set it as 0.45-3.5 mass%.
Ｐ：0.05質量％以下
Ｐは、鋼の融点を低下させるとともに、電気抵抗率を向上させ、溶融効率を向上させる元素である。さらに正極性のガスシールドアーク溶接において、溶滴を微細化し、アークを安定化する作用も有する。しかしＰ含有量が0.05質量％を超えると、正極性のガスシールドアーク溶接において溶融メタルの粘性が著しく低下し、アークが不安定となり、小粒のスパッタが増加する。また、溶接金属の高温割れを生じる危険性が増大する。したがって、Ｐは0.05質量％以下が好ましい。より好ましくは0.03質量％以下である。一方、 鋼素線の鋼材を溶製する製鋼段階でＰを低減するためには長時間を要するので、生産性向上の観点から 0.002質量％以上が望ましい。そのため、0.002〜0.03質量％とするのが一層好ましい。
P: 0.05% by mass or less P is an element that lowers the melting point of steel, improves electrical resistivity, and improves melting efficiency. Furthermore, in positive polarity gas shielded arc welding, it has the effect | action which refines a droplet and stabilizes an arc. However, when the P content exceeds 0.05% by mass, the viscosity of the molten metal is remarkably lowered in positive gas shielded arc welding, the arc becomes unstable, and small particle spatter increases. In addition, the risk of hot cracking of the weld metal increases. Therefore, P is preferably 0.05% by mass or less. More preferably, it is 0.03 mass% or less. On the other hand, since it takes a long time to reduce P in the steelmaking stage where the steel material of the steel wire is melted, 0.002% by mass or more is desirable from the viewpoint of improving productivity. Therefore, it is more preferable to set it as 0.002-0.03 mass%.
Ｓ：0.05質量％以下
Ｓは、溶融メタルの粘性を低下させ、溶接用鋼ワイヤの先端に懸垂した溶滴の離脱を促進し、正極性のガスシールドアーク溶接においてアークを安定化する。またＳは、正極性のガスシールドアーク溶接においてアークを広げ、溶融メタルの粘性を低下させてビードを平滑にする効果も有する。しかしＳ含有量が0.05質量％を超えると、小粒のスパッタが増加するとともに、溶接金属の靭性が低下する。したがって、Ｓは0.05質量％以下が好ましい。一方、 鋼素線の鋼材を溶製する製鋼段階でＳを低減するためには長時間を要するので、生産性向上の観点から0.002質量％以上が望ましい。そのため、0.002〜0.02質量％とするのが一層好ましい。
S: 0.05% by mass or less S lowers the viscosity of the molten metal, promotes the detachment of the droplet suspended from the tip of the steel wire for welding, and stabilizes the arc in positive polarity gas shielded arc welding. S also has the effect of smoothing the bead by spreading the arc in positive gas shielded arc welding and lowering the viscosity of the molten metal. However, when the S content exceeds 0.05% by mass, the spatter of small grains increases and the toughness of the weld metal decreases. Therefore, S is preferably 0.05% by mass or less. On the other hand, since it takes a long time to reduce S in the steelmaking stage where the steel material of the steel wire is melted, 0.002% by mass or more is desirable from the viewpoint of improving productivity. Therefore, it is more preferable to set it as 0.002-0.02 mass%.
さらに本発明では、上記した組成に加えて、鋼素線がCa，Ti，Zr，Ca，Alを含有することが好ましい。
Ca：0.0008質量％以下
Caは、鋼素線の鋼材を溶製する製鋼段階および鋳造段階で不純物として混入する。さらに鋼素線の伸線段階においても不純物として混入する。Ca含有量0.0008質量％を超えると、アークが不安定になる。したがって、Caは0.0008質量％以下が好ましい。
Furthermore, in the present invention, it is preferable that the steel wire contains Ca, Ti, Zr, Ca, and Al in addition to the above-described composition.
Ca: 0.0008 mass% or less
Ca is mixed as an impurity in the steelmaking and casting stages where the steel material of the steel wire is melted. Furthermore, it is mixed as an impurity in the drawing stage of the steel strand. When the Ca content exceeds 0.0008 mass%, the arc becomes unstable. Therefore, Ca is preferably 0.0008% by mass or less.
Ti：0.02〜0.30質量％，Zr：0.02〜0.30質量％，Al：0.02〜0.50質量％のうちの１種または２種以上
Ti，Zr，Alは、いずれも強脱酸剤として作用するとともに、溶接金属の強度を増加する元素である。さらに溶融メタルの脱酸によって粘性の低下を抑制してビード形状を安定化（すなわちハンピングビードを抑制）する効果がある。このような効果を有する故に300Ａ以上の高電流溶接において有効な元素であり、必要に応じて添加する。Tiが0.02質量％未満，Zrが0.02質量％未満，Alが0.02質量％未満では、この効果は得られない。一方、 Tiが0.30質量％を超える場合，Zrが0.30質量％を超える場合，Alが0.50質量％を超える場合は、溶滴が粗大化して大粒のスパッタが多量に発生する。したがって、Ti，Zr，Alを含有する場合は、Ti：0.02〜0.30質量％，Zr：0.02〜0.30質量％，Al：0.02〜0.50質量％の範囲内を満足するのが好ましい。
One or more of Ti: 0.02-0.30 mass%, Zr: 0.02-0.30 mass%, Al: 0.02-0.50 mass%
Ti, Zr, and Al are elements that act as strong deoxidizers and increase the strength of the weld metal. Further, there is an effect of stabilizing the bead shape (ie, suppressing the humping bead) by suppressing the decrease in viscosity by deoxidation of the molten metal. Since it has such an effect, it is an effective element in high current welding of 300 A or more, and is added as necessary. This effect cannot be obtained if Ti is less than 0.02 mass%, Zr is less than 0.02 mass%, and Al is less than 0.02 mass%. On the other hand, when Ti exceeds 0.30% by mass, Zr exceeds 0.30% by mass, or Al exceeds 0.50% by mass, the droplets become coarse and large spatters are generated. Therefore, when Ti, Zr, and Al are contained, it is preferable to satisfy the ranges of Ti: 0.02 to 0.30 mass%, Zr: 0.02 to 0.30 mass%, and Al: 0.02 to 0.50 mass%.
さらに必要に応じて下記の元素を添加しても、本発明の効果を減じるものではない。
Cr：0.02〜3.0質量％，Ni：0.05〜3.0質量％，Mo：0.05〜1.5質量％，Cu：0.05〜3.0質量％，Ｂ：0.0005〜0.015質量％
Cr，Ni，Mo，Cu，Ｂは、いずれも溶接金属の強度を増加し、耐候性を向上させる元素である。これらの元素の含有量が微少である場合は、このような効果は得られない。一方、過剰に添加すると、溶接金属の靭性の低下を招く。したがって、Cr，Ni，Mo，Cu，Ｂを含有する場合は、Cr：0.02〜3.0質量％，Ni：0.05〜3.0質量％，Mo：0.05〜1.5質量％，Cu：0.05〜3.0質量％，Ｂ：0.0005〜0.015質量％の範囲内を満足するのが好ましい。
Furthermore, the effects of the present invention are not reduced by adding the following elements as necessary.
Cr: 0.02-3.0 mass%, Ni: 0.05-3.0 mass%, Mo: 0.05-1.5 mass%, Cu: 0.05-3.0 mass%, B: 0.0005-0.015 mass%
Cr, Ni, Mo, Cu, and B are all elements that increase the strength of the weld metal and improve the weather resistance. When the content of these elements is very small, such an effect cannot be obtained. On the other hand, when it adds excessively, the fall of the toughness of a weld metal will be caused. Therefore, when Cr, Ni, Mo, Cu, and B are contained, Cr: 0.02 to 3.0 mass%, Ni: 0.05 to 3.0 mass%, Mo: 0.05 to 1.5 mass%, Cu: 0.05 to 3.0 mass%, B : It is preferable to satisfy the range of 0.0005 to 0.015 mass%.
Nb：0.005〜0.05質量％，Ｖ：0.005〜0.05質量％
Nb，Ｖは、いずれも溶接金属の強度，靭性を向上し、アークの安定性を向上させる元素である。これらの元素の含有量が微少である場合は、このような効果は得られない。一方、過剰に添加すると、溶接金属の靭性の低下を招く。したがって、Nb，Ｖを含有する場合は、Nb：0.005〜0.05質量％，Ｖ：0.005〜0.05質量％の範囲内を満足するのが好ましい。
Nb: 0.005-0.05 mass%, V: 0.005-0.05 mass%
Nb and V are elements that improve the strength and toughness of the weld metal and improve the stability of the arc. When the content of these elements is very small, such an effect cannot be obtained. On the other hand, when it adds excessively, the fall of the toughness of a weld metal will be caused. Therefore, when Nb and V are contained, it is preferable to satisfy the ranges of Nb: 0.005 to 0.05 mass% and V: 0.005 to 0.05 mass%.
上記した鋼素線の成分以外の残部は、Feおよび不可避的不純物である。ここで不可避的不純物とはＯ，Ｎである。
Ｏ，Ｎは鋼材を溶製する段階や鋼素線を製造する段階で不可避的に混入する代表的な不可避的不純物であるが、溶滴を微細化する効果を有する。Ｏ，Ｎの含有量が、いずれも0.001〜0.02質量％の範囲内であれば、溶滴の微細化が顕著になる。しかし、この範囲を外れるとアークの安定化が阻害される。より好ましくは0.001〜0.008質量％である。
The balance other than the components of the steel strand described above is Fe and inevitable impurities. Here, inevitable impurities are O and N.
O and N are typical inevitable impurities that are inevitably mixed in the stage of melting a steel material or the stage of manufacturing a steel strand, but have the effect of miniaturizing the droplets. If the contents of O and N are both in the range of 0.001 to 0.02% by mass, the refinement of the droplets becomes remarkable. However, out of this range, arc stabilization is hindered. More preferably, it is 0.001-0.008 mass%.
次に、本発明の溶接用鋼ワイヤの製造方法について説明する。
転炉または電気炉等を用いて、上記した組成を有する溶鋼を溶製する。この溶鋼の溶製方法は、特定の技術に限定せず、従来から知られている技術を使用する。次いで、得られた溶鋼を、連続鋳造法や造塊法等によって鋼材（たとえばビレット等）を製造する。この鋼材を加熱した後、熱間圧延を施し、さらに乾式の冷間圧延（すなわち伸線）を施して鋼素線を製造する。熱間圧延や冷間圧延の操業条件は、特定の条件に限定せず、所望の寸法形状の鋼素線を製造する条件であれば良い。
Next, the manufacturing method of the steel wire for welding of this invention is demonstrated.
Using a converter or an electric furnace, molten steel having the above composition is produced. The melting method of the molten steel is not limited to a specific technique, and a conventionally known technique is used. Next, a steel material (for example, a billet) is manufactured from the obtained molten steel by a continuous casting method, an ingot-making method, or the like. After this steel material is heated, hot rolling is performed, and dry cold rolling (that is, wire drawing) is further performed to manufacture a steel strand. The operating conditions for hot rolling and cold rolling are not limited to specific conditions, and may be any conditions as long as they produce a steel wire having a desired size and shape.
さらに鋼素線は、焼鈍−酸洗−銅めっき−伸線加工−潤滑剤塗布の工程を必要に応じて順次施して、所定の製品すなわち溶接用鋼ワイヤとなる。なお本発明では、必ずしも鋼素線に銅めっきを施す必要はなく、鋼素線の表面に潤滑剤を塗布した溶接用鋼ワイヤであっても何ら支障なく使用できる。
鋼素線の表面に潤滑剤を安定して付着させ、給電の安定性を向上するために、鋼素線の平坦度（＝実表面積／理論表面積）を1.0005以上1.01未満とするのが好ましい。鋼素線の平坦度は、伸線加工で使用するダイスの管理を厳格に行なうことによって、1.0005以上1.01未満の範囲に維持することは可能である。
Further, the steel wire is sequentially subjected to annealing, pickling, copper plating, wire drawing, and lubricant application as necessary to form a predetermined product, that is, a steel wire for welding. In the present invention, it is not always necessary to apply copper plating to the steel wire, and even a steel wire for welding in which a lubricant is applied to the surface of the steel wire can be used without any trouble.
In order to stably adhere the lubricant to the surface of the steel wire and improve the stability of the power supply, it is preferable that the flatness (= actual surface area / theoretical surface area) of the steel wire is 1.005 or more and less than 1.01. The flatness of the steel wire can be maintained in the range of 1.0005 or more and less than 1.01 by strictly managing the dies used in the wire drawing.
鋼素線の表面に銅めっきを施す場合は、厚さ0.5μｍ以上の銅めっきを施すことによって、溶接用鋼ワイヤの給電不良に起因するアークの不安定化を防止できる。なお、銅めっきの厚さを0.8μｍ以上とすると、給電不良防止の効果が顕著に発揮されるので一層好ましい。このようにして銅めっきを厚目付とすることによって、給電チップの損耗も低減できるという効果も得られる。 When copper plating is applied to the surface of the steel element wire, it is possible to prevent arc instability due to poor power feeding of the welding steel wire by performing copper plating with a thickness of 0.5 μm or more. In addition, it is more preferable that the thickness of the copper plating is 0.8 μm or more because an effect of preventing power feeding failure is remarkably exhibited. By making the copper plating thicker in this way, there is also an effect that the wear of the power supply tip can be reduced.
溶接用鋼ワイヤの送給性を向上するために、溶接用鋼ワイヤの表面（すなわち鋼素線の表面あるいは銅めっきの表面）に潤滑油を塗布しても良い。潤滑油の塗布量は、溶接用鋼ワイヤ10kgあたり0.35〜1.70ｇの範囲内が好ましい。
なお、溶接用鋼ワイヤを製造する工程で、溶接用鋼ワイヤの表面に種々の不純物が付着する。特に固体の不純物の付着量を、溶接用鋼ワイヤ10kgあたり0.01ｇ以下に抑制すると、給電の安定性が一層向上する。
In order to improve the feedability of the welding steel wire, lubricating oil may be applied to the surface of the welding steel wire (that is, the surface of the steel wire or the surface of the copper plating). The amount of lubricant applied is preferably in the range of 0.35 to 1.70 g per 10 kg of welding steel wire.
In the process of manufacturing a welding steel wire, various impurities adhere to the surface of the welding steel wire. In particular, when the amount of solid impurities deposited is suppressed to 0.01 g or less per 10 kg of the welding steel wire, the power feeding stability is further improved.
このようして製造した溶接用鋼ワイヤを用いてガスシールドアーク溶接を行なう際の好適な溶接条件について、以下に説明する。
初層（すなわち開先の底部）の溶接を行なうにあたって、下記の (1)式で算出される指標ＱＬ値を1.5〜10.0の範囲内に調整する。
ＱＬ＝Ｉ×Ｅ／〔Ｓ×（Ｇ＋５×tanθ）〕／60 ・・・ (1)
Ｉ：溶接電流（Ａ）
Ｅ：溶接電圧（Ｖ）
Ｓ：溶接速度（mm／sec ）
θ：開先角度（°）
Ｇ：ルートギャップ（mm）
初層の溶け込み形状は、溶接電流Ｉ（Ａ），溶接電圧Ｅ（Ｖ），溶接速度Ｓ（mm／sec ），開先角度θ（°），ルートギャップＧ（mm）の設定に応じて多大な影響を受ける。溶接電流Ｉと溶接電圧Ｅを高く設定し、溶接速度Ｓを低く抑えると、鋼板への入熱を大きくすることができる。しかし狭い開先ではＱＬ値が10.0を超えると、初層の溶接にて過剰な溶融金属がアークよりも先行し、鋼材の溶融を阻害するので、安定した溶け込みが得られない。一方、ＱＬ値が1.5未満では、初層の溶接にて鋼板への入熱が不足し、十分な溶け込みが得られない。したがって、ＱＬ値は1.5〜10.0の範囲内を満足する必要がある。
Suitable welding conditions when performing gas shielded arc welding using the steel wire for welding thus manufactured will be described below.
When welding the first layer (that is, the bottom of the groove), the index QL value calculated by the following equation (1) is adjusted within the range of 1.5 to 10.0.
QL = I × E / [S × (G + 5 × tan θ)] / 60 (1)
I: Welding current (A)
E: Welding voltage (V)
S: Welding speed (mm / sec)
θ: groove angle (°)
G: Route gap (mm)
The penetration shape of the first layer varies greatly depending on the settings of welding current I (A), welding voltage E (V), welding speed S (mm / sec), groove angle θ (°), and root gap G (mm). Is affected. When the welding current I and the welding voltage E are set high and the welding speed S is kept low, the heat input to the steel plate can be increased. However, when the QL value exceeds 10.0 in a narrow groove, an excessive molten metal precedes the arc in the first layer welding and inhibits melting of the steel material, so that stable penetration cannot be obtained. On the other hand, if the QL value is less than 1.5, heat input to the steel sheet is insufficient in the first layer welding, and sufficient penetration cannot be obtained. Therefore, the QL value needs to satisfy the range of 1.5 to 10.0.
さらに、初層の溶接を行なうにあたって、下記の (2)式で算出される指標ＱＨ値を1.0以上に調整する。
ＱＨ＝〔Ｇ×Ｓ×60×（Ｇ＋tanθ）／（Ｉ×Ｅ）〕＋tanθ ・・・ (2)
Ｉ：溶接電流（Ａ）
Ｅ：溶接電圧（Ｖ）
Ｓ：溶接速度（mm／sec ）
θ：開先角度（°）
Ｇ：ルートギャップ（mm）
狭開先突合せ溶接では、溶接金属の幅に対して高さが大きくなりやすい。そのため、溶接金属の凝固過程にて、溶接継手中央部で溶接金属が不足することに起因する欠陥が発生する。このような欠陥は、高温割れ（あるいは凝固割れ）と呼ばれる。溶接用鋼ワイヤの鋼素線にREMを添加することによって、高温割れを抑制する効果が得られる。さらに高温割れの抑制効果を一層高めるために、１パスあたり（特に初層）の溶接金属量を減少する必要がある。本発明では、初層の溶接金属量の指標として上記のＱＨ値を導入する。発明者らの研究によれば、ＱＨ値が1.0以上で高温割れの抑制効果が顕著に発揮される。したがってＱＨ値は1.0以上を満足する必要がある。
Furthermore, when welding the first layer, the index QH value calculated by the following equation (2) is adjusted to 1.0 or more.
QH = [G × S × 60 × (G + tanθ) / (I × E)] + tanθ (2)
I: Welding current (A)
E: Welding voltage (V)
S: Welding speed (mm / sec)
θ: groove angle (°)
G: Route gap (mm)
In narrow groove butt welding, the height tends to increase with respect to the width of the weld metal. Therefore, in the solidification process of the weld metal, a defect is generated due to the lack of weld metal at the center of the weld joint. Such defects are called hot cracks (or solidification cracks). By adding REM to the steel wire of the welding steel wire, the effect of suppressing high temperature cracking can be obtained. Furthermore, in order to further enhance the effect of suppressing hot cracking, it is necessary to reduce the amount of weld metal per pass (particularly the first layer). In the present invention, the above QH value is introduced as an index of the amount of weld metal in the first layer. According to the research by the inventors, when the QH value is 1.0 or more, the effect of suppressing hot cracking is remarkably exhibited. Therefore, the QH value needs to satisfy 1.0 or more.
シールドガスは、通常のガスシールドアーク溶接で用いるシールドガスを使用する。ただし上記の(A)に記載したＭＡＧ溶接法では、高価なArのが含有量が高い。したがって、Ar含有量を低減して、上記の(B)に記載した炭酸ガスシールドアーク溶接で用いるシールドガス（すなわちＣＯ2 含有量：50体積％以上）を使用するのが好ましい。より好ましくは、ＣＯ2 含有量：100体積％（すなわち純ＣＯ2 ガス）である。 As the shielding gas, a shielding gas used in normal gas shield arc welding is used. However, in the MAG welding method described in (A) above, the content of expensive Ar is high. Therefore, it is preferable to use the shielding gas (that is, CO 2 content: 50% by volume or more) used in the carbon dioxide shielded arc welding described in (B) above by reducing the Ar content. More preferably, the CO 2 content is 100% by volume (that is, pure CO 2 gas).
溶接用鋼ワイヤの極性は、正極性とするのが好ましい。鋼素線に添加されたREMが、正極性の溶接におけるアークを集中させる効果を発揮するので、１パスあたりの溶接金属量を減少しても、十分な溶け込みが得られる。
本発明を適用する開先の形状は、特定の形状に限定せず、種々の開先に適用できる。たとえば、図１(a)に示すＶ型開先，図１(b)に示すレ型開先，図１(c)に示すＩ型開先等に適用できる。図中のｔは厚鋼板１の板厚，Ｇはルートギャップ，θは開先角度を示す。なお図１(c)のＩ型開先では、開先角度θ＝０°である。
The polarity of the welding steel wire is preferably positive. Since REM added to the steel wire exerts the effect of concentrating the arc in positive polarity welding, even if the amount of weld metal per pass is reduced, sufficient penetration can be obtained.
The shape of the groove to which the present invention is applied is not limited to a specific shape, and can be applied to various grooves. For example, the present invention can be applied to a V-shaped groove shown in FIG. 1A, a lave groove shown in FIG. 1B, an I-shaped groove shown in FIG. In the figure, t is the thickness of the
本発明は、ルートギャップと開先角度とを小さくして狭開先とすることによってガスシールドアーク溶接の能率向上を図る際に、開先の底部においてもアークの安定性を維持し、安定した溶け込みを得るものである。したがって、板厚の大きい厚鋼板に適用するほど多大な効果が得られる。このような観点から、板厚ｔが12mm以上の厚鋼板に適用し、そのルートギャップＧは２mm以下，開先角度θは30°以下とする。 In the present invention, when the efficiency of gas shielded arc welding is improved by reducing the root gap and the groove angle to make the groove narrower, the stability of the arc is maintained even at the bottom of the groove, and stable. It is what gets melted. Therefore, a greater effect can be obtained as a thick steel plate is applied. From such a point of view, the present invention is applied to a thick steel plate having a thickness t of 12 mm or more, the root gap G is 2 mm or less, and the groove angle θ is 30 ° or less.
製鋼段階で成分を調整し、連続鋳造によって製造されたビレットを熱間圧延して、直径 5.5〜7.0mm の線材とし、次いで冷間圧延（すなわち伸線）によって直径 2.0〜2.8mm とした。これらの線材を露点10℃以下の窒素雰囲気（Ｏ2 200体積ppm 以下，ＣＯ2 0.1体積％以下）で焼鈍し、酸洗を施して脱スケールを行なった後、必要に応じてCuめっきを施し、さらに冷間で伸線加工を施して、直径 0.8〜1.5mmの鋼素線を製造した。さらに鋼素線に潤滑剤を塗布（溶接用鋼ワイヤ10kgあたり0.5〜0.8ｇ）することによって、十分な送給性を確保できるように調整した。得られた鋼素線の成分は、表１に示す通りである。なお、REM は、質量比Ce：La：Ｙ＝６：３：１のミッシュメタルである。 The components were adjusted in the steelmaking stage, and the billet produced by continuous casting was hot-rolled to obtain a wire having a diameter of 5.5 to 7.0 mm, and then cold-rolled (ie, drawn) to a diameter of 2.0 to 2.8 mm. These wires are annealed in a nitrogen atmosphere with a dew point of 10 ° C or less (O 2 200 volume ppm or less, CO 2 0.1 volume% or less), pickled, descaled, and then plated with Cu as necessary. Further, cold drawing was performed to produce a steel wire having a diameter of 0.8 to 1.5 mm. Furthermore, it adjusted so that sufficient feedability could be ensured by apply | coating a lubricant to a steel strand (0.5-0.8g per 10kg of welding steel wires). The components of the obtained steel wire are as shown in Table 1. Note that REM is a misch metal having a mass ratio Ce: La: Y = 6: 3: 1.
これらの溶接用鋼ワイヤを使用して、厚鋼板の狭開先突合せ溶接（初層のみ）を行なった。その溶接条件は表２に示すとおりである。 Using these welding steel wires, narrow gap butt welding (first layer only) of thick steel plates was performed. The welding conditions are as shown in Table 2.
得られた初層のみの溶接継手（溶接長250mm）のスタートから20mm，100mm，中央およびクレーター側から20mm，100mmの検査位置（合計５ケ所）で、溶け込みと割れを評価した。その結果を表３に示す。 Penetration and cracking were evaluated at 20 mm and 100 mm from the start of the first welded joint (weld length 250 mm) obtained, and 20 mm and 100 mm from the crater side (total of 5 locations). The results are shown in Table 3.
溶け込みの評価は、５ケ所の検査位置の溶け込みが全て深さ１mm以上であったものを良（○），５ケ所の溶け込み深さが0.2mm以上で深さ１mm未満の溶け込みが１ケ所でも存在するものを可（△），深さ０mm（すなわち未溶融）の溶け込みが１ケ所でも存在するものを不良（×）とした。
割れの評価は、５ケ所の検査位置で割れが観察されなかったものを良（○），割れが１ケ所でも存在するものを不良（×）とした。
Penetration evaluation is good if the penetration at all 5 inspection positions is 1 mm or more in depth (○), 5 penetration depths are 0.2 mm or more, and there is penetration at 1 depth in 1 place. What was to be allowed was acceptable (Δ), and one with a depth of 0 mm (that is, unmelted) was present even at one location was regarded as defective (x).
In the evaluation of cracks, the case where no cracks were observed at five inspection positions was judged as good (◯), and the case where cracks were present even at one place was judged as bad (x).
表３から明らかなように、発明例では安定した溶け込みが得られた。一方、本発明の範囲を外れる比較例では、溶け込みが不十分で未溶融のものがあり、しかも割れが生じたものもあった。 As is clear from Table 3, in the inventive examples, stable penetration was obtained. On the other hand, in comparative examples that are outside the scope of the present invention, there were some that were not sufficiently melted and unmelted, and some cracks occurred.
１ 厚鋼板
Ｇ ルートギャップ
ｔ 板厚
θ 開先角度
1 Thick steel plate G Root gap t Plate thickness θ Groove angle
Claims (3)
ＱＬ＝Ｉ×Ｅ／〔Ｓ×（Ｇ＋５× tanθ）〕／60 ・・・ (1)
ＱＨ＝〔Ｇ×Ｓ×60×（Ｇ＋ tanθ）／（Ｉ×Ｅ）〕＋ tanθ ・・・ (2)
Ｉ：溶接電流（Ａ）
Ｅ：溶接電圧（Ｖ）
Ｓ：溶接速度（mm／sec ）
θ：開先角度（°）
Ｇ：ルートギャップ（mm） A steel plate with a thickness of 12 mm or more is used in a narrow groove butt welding method in which multi-layer gas shielded arc welding of thick steel plates is performed using steel wires for welding consisting of steel wires containing 0.015 to 0.100% by mass of rare earth elements. The gas gap arc welding of the first layer at the bottom of the narrow gap with a root gap of 2 mm or less and a groove angle of 30 ° or less, with a welding speed of 15 to 25 mm / sec and the following The narrow gap is obtained under the condition that the QL value calculated by the equation (1) satisfies the range of 1.5 to 10.0 and the QH value calculated by the following equation (2) satisfies the range of 1.0 or more. A narrow groove butt welding method characterized by obtaining deep penetration at the bottom.
QL = I × E / [S × (G + 5 × tan θ)] / 60 (1)
QH = [G × S × 60 × (G + tan θ) / (I × E)] + tan θ (2)
I: Welding current (A)
E: Welding voltage (V)
S: Welding speed (mm / sec)
θ: groove angle (°)
G: Route gap (mm)
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| CN108907419A (en) * | 2018-07-20 | 2018-11-30 | 四川汇源钢建装配建筑有限公司 | A kind of single V groove with root face welding method and weldment |
| CN113579423A (en) * | 2021-08-11 | 2021-11-02 | 长江精工钢结构(集团)股份有限公司 | Welding method for manually welding small groove of T-shaped welding seam and welding gun nozzle matched with same |
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