JP3589917B2 - Flux-cored wire for duplex stainless steel welding - Google Patents
Flux-cored wire for duplex stainless steel welding Download PDFInfo
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- JP3589917B2 JP3589917B2 JP31571399A JP31571399A JP3589917B2 JP 3589917 B2 JP3589917 B2 JP 3589917B2 JP 31571399 A JP31571399 A JP 31571399A JP 31571399 A JP31571399 A JP 31571399A JP 3589917 B2 JP3589917 B2 JP 3589917B2
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Description
【0001】
【発明の属する技術分野】
本発明は、二相ステンレス鋼の溶接に使用され、溶接金属性能が良好な全姿勢溶接性に優れた二相ステンレス鋼溶接用フラックス入りワイヤに関する。
【0002】
【従来の技術】
SUS329J3L、SUS329J4Lのような二相ステンレス鋼は、優れた耐食性及び強度特性を持つステンレス鋼である。耐孔食性、耐隙間腐食性が要求される化学プラント機器や油井、ガス井等の耐食材料として、また、強度も高いことから、建築や車両等の構造材としても用いられている。これらの溶接に使用される材料には、母材と同等の溶接金属性能と良好な溶接作業性が求められる。溶接材料の中でも高能率に溶接できるフラックス入りワイヤが多く使用されるようになり特にその要求が高い。しかし、二相ステンレス鋼を従来のオーステナイト系ステンレス鋼溶接用フラックス入りワイヤのスラグ系をベースとしたフラックス入りワイヤを用いて溶接した場合、溶接直後にスラグが飛散したり、一部が溶接ビードに焼き付いて残るという問題がある。さらに、全姿勢での溶接が困難であり、溶接電流を下げたり、高い溶接技量を必要とする。これらは溶接作業能率を著しく低下させる。
【0003】
二相ステンレス鋼のような高窒素ステンレス鋼溶接用のフラックス入りワイヤは特開平3−294094号公報に開示されている。しかし、同公報ワイヤは主成分であるTiO2とSiO2、ZrO2、さらに合金成分を限定して溶接部の強度を要求したのもで、立向、上向等の姿勢での溶接は困難であった。また、特開平9−239586号公報にも開示されているが、同公報ワイヤは主成分であるTiO2とSiO2、及び金属弗化物、スラグ剤成分の合計量、さらに合金成分を限定して高隙間耐食性を要求したものであり、立向、上向等の姿勢での溶接は困難であった。そこで、溶接作業性及び溶接金属性能が良好な全姿勢溶接性に優れた二相ステンレス鋼溶接用フラックス入りワイヤの開発が強く要望されていた。
【0004】
【発明が解決しようとする課題】
本発明は上記課題を解決するために、ワイヤ中のスラグ剤成分と金属弗化物、金属Ti量について種々検討したものであり、二相ステンレス鋼の全姿勢溶接において、アークが安定し、スパッタ発生量が少なく、さらにビード形状、スラグの被包性及び剥離性が優れ、かつ溶接金属性能が良好な二相ステンレス鋼の全姿勢溶接用フラックス入りワイヤを提供することを目的とする。
【0005】
【課題を解決するための手段】
本発明者らは、溶着金属のフェライト量が多い二相ステンレス鋼の溶着金属の伸びが低下する原因について究明した結果、溶着金属中に多量の水素を含有し水素脆化を起こすこと、そして、溶着金属中の水素量はTiと関係があり、ワイヤ中の金属Ti量が増加すると溶着金属中の水素量も増加することを知見した。
【0006】
本発明は、上記知見に基づいて完成したもので、スラグ剤成分を所定の割合とすると共に、金属Tiを所定割合に制限することにより、前記課題を達成し得たものである。
【0007】
本発明の要旨とするところは、ステンレス鋼からなる外皮の内部にワイヤ全重量に対して重量%でTiO2:3.4〜9.9%、SiO2:0.2〜2.5%、Al2O3:0.3〜1.7%、金属弗化物(F換算値):0.33〜0.5%、金属Ti(Ti換算値):0.08〜0.44%とし、かつスラグ剤成分の合計がワイヤ全重量の7.3〜11.1%であるフラックスをステンレス鋼外皮内に18〜26%充填してなることを特徴とする二相ステンレス鋼の全姿勢溶接用フラックス入りワイヤにある。
【0008】
【発明の実施の形態】
以下に本発明ステンレス鋼溶接用フラックス入りワイヤの各成分限定理由について説明する。
【0009】
まず、スラグ剤成分の限定理由について説明する。
【0010】
充填フラックス中のTiO2は、アークを安定にし、被包性及び剥離性の良いスラグを形成する。さらに、スラグの凝固を早め、立向及び上向溶接中に溶融金属の垂れを防ぎビード形状を良好にする効果がある。3.4%未満ではアークが不安定となり、スラグ被包性及び剥離性が悪く、また、立向及び上向溶接で溶融金属が垂れ、ビード形状が不良となる。9.9%を超えるとスラグの流動性が低下し、ビード形状が不良となる。また、スパッタ発生量が増加するばかりか、スラグ巻込みが発生しやすくなる。TiO2としては、ルチール、チタンスラグ、イルミナイト、チタン酸カリ、チタン酸ソーダ等が使用できる。
【0011】
SiO2は、スラグの流動性調整に必要で、被包性及び剥離性の良いスラグを形成し、ビード形状を良化させる成分であるが、0.2%未満ではスラグの流動性が悪くビード形状が不良となり、2.5%を超えると、スラグが流れやすくなり、立向及び上向溶接で溶融金属が垂れ、全姿勢溶接が困難となりビード形状が不良となる。さらに、スラグの焼付きを生じ、スラグ剥離性が低下する。SiO2としては、硅砂、硅石の他、カリ長石等が使用できる。
【0012】
Al2O3はスラグ流動性の調整剤であり、被包性及び剥離性の良いスラグを形成し、ビード形状を良好とする成分であるが、0.3%未満ではスラグが流れやすくなり、立向及び上向溶接で溶融金属が垂れ、全姿勢溶接が困難となりビード形状が不良となる。さらに、スラグの被包性が悪く、スラグの焼付きを生じ、スラグの剥離性が低下する。1.7%を超えると、スパッタが発生しやすくなり、さらに、スラグの粘性が低下し、ビード形状が不良となる。Al2O3としては、アルミナ、カリ長石等が使用できる。
【0013】
金属弗化物は、スラグ融点の調整であり、被包性及び剥離性の良いスラグ形成し、ビード形状を良好とする成分であるが、F換算値で0.33%以上がスラグの被包性及び剥離性に好ましく、0.5%を超えるとスラグの融点が著しく低下し、立向及び上向溶接で溶融金属が垂れ、全姿勢溶接が困難となり、ビード形状が不良となる。また、弗素ガス発生に伴いヒュームが多量に発生する。金属弗化物はLiF、MgF2、AlF2、K2Zr2F6等が使用でき、いずれの金属弗化物を使用しても同様な効果が得られる。
【0014】
次に、合金成分を調整する金属Tiについては、金属Tiはその殆どがアーク中で酸化反応しTiO2となりスラグとして作用するが、本来スラグ形成剤として使用しているTiO2の融点が1840℃であるのに対し、金属Tiで1660℃、Fe−Tiで1317℃とより融点が低いため早い時点でスラグ化し、凝固も早期に始まり溶融金属の垂れを防止する。そのため、立向及び上向溶接を容易にする。また、スラグの流動性を調整して被包性及び剥離性の良いスラグを形成し、ビード形状を良好にする成分であるが、Ti換算値で0.08%未満では効果なく立向及び上向溶接中の溶融金属が垂れやすく、溶接が困難なばかりか、ビード形状が不良となる。
【0015】
しかしながら、金属Tiを多量に含有した場合溶着金属の伸びが低下する傾向が認められた。溶着金属のフェライト量が25%を超える二相ステンレス鋼では、図1に示すように溶着金属中に多量の水素を含有すると水素脆化を起こし、溶着金属の引張試験において伸びが著しく低下する。
【0016】
そこで本発明者らは、溶着金属中の水素量とTi量に着目し検討した結果、図2に示すように溶着金属中の水素量は、Tiと関係があり、ワイヤ中のTi(Ti換算値)量が増加すると、溶着金属中の水素量も増加することが判明した。
【0017】
これは、Tiが水素の拡散を妨げ、固定しているためと考えられる。したがって、延性確保には水素脆化を起こさないために水素を極力押さえる必要があり、そのためにはワイヤ中のTi量を制限する必要がある。
【0018】
そのため、ワイヤ中の金属TiをTi換算値でワイヤ全重量に対して0.44%以下とする。したがって、金属Ti(Ti換算値)はワイヤ全重量に対して重量%で0.08〜0.44%とする。Ti源としては金属Ti、Fe−Ti等が使用できる。
【0019】
次に、スラグ剤成分の合計量及びフラックス充填率について説明すると、フラックス中のスラグ剤成分は、被包性及び剥離性の良いスラグを形成し、ビード形状を良好にする。スラグ剤成分の合計が合計で7.3%未満では、立向及び上向溶接において溶融金属の保持が十分できず、溶接が困難となり、ビード形状が不良となる。さらにスラグの被包性及び剥離性が不十分となり、スラグ焼付きを生じ、スラグ剥離性が低下する。11.1%を超えるとスパッタが増加し、さらにスラグ過剰となりスラグ巻込みの欠陥が発生する。なお、本発明におけるスラグ剤成分とは、酸化物、弗化物等の非金属成分、不純物としてのP、S等を意味するものである。
【0020】
ステンレス鋼外皮へのフラックス充填率が18%未満では、外皮の肉厚が厚く、溶滴が肥大化しスパッタが増加する。26%を超えると逆に外皮の肉厚が薄く、伸線加工中に断線が多発し、著しく生産能率を低下させる。
【0021】
また、充填フラックスは溶接する二相ステンレス鋼板成分によって合金成分を調整する。調整剤としてNi、Cr、Mn、Mo、Si、Fe、Ti、Al、ステンレス粉、窒化金属等を用いる。さらに原材料粒度、フラックス成分、充填方法等に応じて固着剤によって造粒して用いることもあるが、その場合には固着剤からもたらされる成分、例えば水ガラスの場合では、SiO2、Na2O、K2O等が増加することをあらかじめ考慮するように原料の配合を行う必要がある。
【0022】
なお、本発明のフラックス入りワイヤとは、図3(a)〜(d)にその例を示す様な断面形状のワイヤで、オーステナイト系またはオーステナイト−フェライト系のステンレス鋼のパイプあるいは帯鋼から成る外皮1に、充填フラックス2を被包したもので、図3(a)に示す様な継ぎ目のないもの、あるいは図3(b)〜(d)の如く継ぎ目3を有するものでもよい。
【0023】
【実施例】
表1に示す成分のオーステナイト系、オーステナイト−フェライト系ステンレス鋼のパイプ及び帯鋼を用い、表2及び表3に示すフラックスをワイヤ全重量に対する充填率を変えて、ワイヤ径1.2mmのステンレス鋼溶接用フラックス入りワイヤを製造した。なお、パイプは所定の充填率にフラックスが入る径まで管引きした後、フラックスを充填した。表2及び表3においてワイヤNo.1〜13が本発明例のフラックス入りワイヤ、No.14〜27が比較例である。
【0024】
【表1】
【0025】
【表2】
【0026】
【表3】
【0027】
溶接作業性評価は、電流160A(DCEP)、電圧24V、シールドガスは100%CO2:20リットル/minの溶接条件で半自動溶接にて評価した。
【0028】
試験鋼板は、表1に示す成分のSUS329J3L鋼板を用いてT字型に組み立て、片側1パス立向上進溶接を行い確認した。さらに、溶接ビードを切断し、断面のスラグ巻込み欠陥の有無を確認した。作業性評価は実用上良好な場合は○、実用上問題がある場合は×とした。溶接作業性がすべて良好なものは、JISZ3323/A1号試験片を採取し、引張試験を行った。判定は、溶接作業性に問題があるもの、引張試験においてAWS規格の伸びが20%以上を満足しないもの、スラグ巻込みが発生しているものは×とした。それらの結果を表4に示す。
【0029】
【表4】
【0030】
本発明例であるワイヤNo.1、3、6〜8およびワイヤNo.10〜13は、TiO2、SiO2、Al2O3、金属弗化物のF換算値、金属TiのTi換算値及びスラグ剤成分の合計が適正量からなるフラックスをステンレス鋼外皮に適量充填されているので、溶接作業性、溶接金属の引張試験においても良好で、生産能率も低下させることなく極めて良好な結果であった。
【0031】
比較例中ワイヤNo.14は、TiO2量が多いのでスパッタが多発し、溶接作業性が劣化した。さらに、スラグの流動性が劣化し、ビード形状が不良となった。さらに、スラグ巻込みの欠陥が発生した。
【0032】
ワイヤNo.15は、TiO2量が少ないのでアーク状態が不安定となり、スラグの被包性及び剥離性が悪くなった。さらに、溶接中の溶融金属が垂れ、ビード形状が不良となった。
【0033】
ワイヤNo.16は、SiO2量が多いのでスラグが流れやすく、溶接中の溶融金属が垂れ、ビード形状が不良となった。さらに、スラグの焼付きを生じ、スラグ剥離性が悪くなった。
【0034】
ワイヤNo.17は、SiO2量が少ないのでスラグの流動性が悪く、ビード形状が不良となった。
【0035】
ワイヤNo.18は、Al2O3量が多いのでスパッタが多発した。さらにスラグの粘性が低下し、ビード形状が不良となった。
【0036】
ワイヤNo.19は、Al2O3量が少ないのでスラグが流れやすく、溶接中の溶融金属が垂れ、ビード形状が不良となった。さらに、スラグの被包性が悪く焼付きを生じ、スラグ剥離性が悪くなった。
【0037】
ワイヤNo.20は、金属弗化物のF換算値が多いので弗素ガス発生量が過剰となり溶接ヒュームの発生量が多くなった。また、スラグの融点が下がり、溶接中の溶融金属が垂れ、ビード形状が不良となった。
【0038】
ワイヤNo.21は、金属弗化物のF換算値が少ないのでスラグが溶接金属に均一に被包せず、スラグが焼き付き、スラグ剥離性が悪かった。
【0039】
ワイヤNo.22は、金属Ti量のTi換算値が多いので溶接作業性は良好であるが、溶着金属の引張試験において伸びがAWS規格である20%以上を満足しなかった。
【0040】
ワイヤNo.23は、金属Ti量のTi換算値が少ないのでスラグ凝固が遅く溶接中の溶融金属が垂れ、全姿勢溶接が困難であり、ビード形状も不良となった。
【0041】
ワイヤNo.24は、スラグ剤成分の合計が多いのでスパッタが増加し、スラグ巻込みの欠陥が発生した。
【0042】
ワイヤNo.25は、スラグ剤成分の合計が少ないので、立向及び上向溶接において溶融金属の保持が十分できず、溶接が困難で、ビード形状も不良となった。さらにスラグの被包性が不十分となり、スラグが焼き付きを生じ、スラグ剥離が悪かった。
【0043】
ワイヤNo.26は、フラックス充填率が高いので伸線加工中に断線が多発し、生産能率を著しく低下させた。したがって、ワイヤ径1.2mmまで伸線を行わなかった。
【0044】
ワイヤNo.27は、フラックス充填率の低いので溶滴が肥大化しスパッタが増加した。
【0045】
【発明の効果】
以上詳述したように本発明の二相ステンレス鋼溶接用フラックス入りワイヤは、二相ステンレス鋼の溶接において、機械的性能を満足しつつ、アーク状態、スパッタ発生量、スラグ被包・剥離性等の全姿勢溶接作業性に優れた二相ステンレス鋼溶接用フラックス入りワイヤとして有益である。
【図面の簡単な説明】
【図1】溶着金属の伸びと溶着金属中の水素量の関係を示す図である。
【図2】溶着金属中の水素量とワイヤ中のTi(Ti換算値)量の関係を示す図である。
【図3】フラックス入りワイヤの断面図である。
【符号の説明】
1 外皮
2 充填フラックス
3 継ぎ目[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flux cored wire for duplex stainless steel welding, which is used for welding duplex stainless steel and has excellent weld metal performance and excellent all-position weldability.
[0002]
[Prior art]
Duplex stainless steels such as SUS329J3L and SUS329J4L are stainless steels having excellent corrosion resistance and strength characteristics. It is used as a corrosion-resistant material for chemical plant equipment, oil wells, gas wells, and the like that require pitting and crevice corrosion resistance, and because of its high strength, it is also used as a structural material for buildings and vehicles. The materials used for these weldings are required to have the same weld metal performance as the base metal and good welding workability. Among welding materials, flux-cored wires that can be welded with high efficiency have come to be used in many cases, and the demand for them is particularly high. However, when duplex stainless steel is welded using a flux-cored wire based on the conventional flux-cored wire for welding austenitic stainless steel, the slag may be scattered immediately after welding, or some of it may be welded. There is a problem that it remains after burning. Further, it is difficult to perform welding in all positions, which requires a lower welding current and requires a higher welding skill. These significantly reduce the efficiency of the welding operation.
[0003]
A flux-cored wire for welding high-nitrogen stainless steel such as duplex stainless steel is disclosed in JP-A-3-294094. However, the wire of the publication requires TiO 2 and SiO 2 , ZrO 2 , which are the main components, and the strength of the welded portion by limiting the alloy components, so that it is difficult to perform welding in an upright or upward position. Met. In addition, as disclosed in Japanese Patent Application Laid-Open No. 9-239586, the wire disclosed in the publication is limited in the total amount of TiO 2 and SiO 2 as main components, metal fluorides and slag agent components, and further, alloy components. This required high gap corrosion resistance, and it was difficult to weld in a vertical or upward position. Therefore, there has been a strong demand for the development of a flux-cored wire for duplex stainless steel welding which has excellent welding workability and good weld metal performance and excellent all-position weldability.
[0004]
[Problems to be solved by the invention]
In order to solve the above-mentioned problems, the present invention has variously studied the slag agent component, the metal fluoride, and the amount of metal Ti in a wire. In all-position welding of a duplex stainless steel, an arc is stabilized and spatter is generated. An object of the present invention is to provide a flux cored wire for duplex welding of duplex stainless steel having a small amount, and further having excellent bead shape, slag encapsulation property and peelability, and excellent weld metal performance.
[0005]
[Means for Solving the Problems]
The present inventors have investigated the cause of a decrease in the elongation of the deposited metal of the duplex stainless steel having a large amount of ferrite in the deposited metal, and as a result, contain a large amount of hydrogen in the deposited metal to cause hydrogen embrittlement, and It has been found that the amount of hydrogen in the weld metal is related to Ti, and that the amount of hydrogen in the weld metal increases as the amount of metal Ti in the wire increases.
[0006]
The present invention has been completed based on the above findings, and has achieved the above object by limiting the slag agent component to a predetermined ratio and the metal Ti to a predetermined ratio.
[0007]
It is an aspect of the present invention, TiO 2 in weight percent relative to the inner wire to the total weight of the outer skin made of stainless steel: 3.4~9.9%, SiO 2: 0.2~2.5 %, Al 2 O 3 : 0.3 to 1.7%, metal fluoride (F conversion value): 0.33 to 0.5%, metal Ti (Ti conversion value): 0.08 to 0.44%, A stainless steel shell is filled with 18 to 26% of a flux having a total slag agent component of 7.3 to 11.1% of the total weight of the wire, for all-position welding of duplex stainless steel. In flux cored wire.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The reasons for limiting each component of the flux cored wire for stainless steel welding of the present invention will be described below.
[0009]
First, the reasons for limiting the slag agent components will be described.
[0010]
TiO 2 in the filling flux stabilizes the arc and forms slag with good encapsulation and peeling properties. Further, it has the effect of accelerating the solidification of the slag, preventing the molten metal from sagging during vertical and upward welding, and improving the bead shape. If it is less than 3.4%, the arc becomes unstable, the slag encapsulation property and the peelability are poor, and the molten metal sags in the vertical and upward welding, resulting in a poor bead shape. If it exceeds 9.9%, the fluidity of the slag decreases, and the bead shape becomes poor. Further, not only does the amount of spatter generated increase, but also slag entrainment is likely to occur. As TiO 2 , rutile, titanium slag, illuminite, potassium titanate, sodium titanate and the like can be used.
[0011]
SiO 2 is necessary for adjusting the fluidity of the slag, is a component that forms a slag with good encapsulability and releasability and improves the bead shape, but if it is less than 0.2%, the fluidity of the slag is poor and the bead is poor. If the shape is poor, and if it exceeds 2.5%, the slag becomes easy to flow, the molten metal drips in the vertical and upward welding, welding in all positions becomes difficult, and the bead shape becomes poor. Further, slag seizure occurs, and the slag removability decreases. The SiO 2, silica sand, other Keiseki, potash feldspar and the like can be used.
[0012]
Al 2 O 3 is a slag fluidity regulator, forms a slag having good encapsulation and peeling properties, and is a component that improves the bead shape. Molten metal drips in vertical and upward welding, making it difficult to weld in all positions, resulting in poor bead shape. Furthermore, the encapsulation of the slag is poor, causing seizure of the slag and degrading the slag removability. If it exceeds 1.7%, spatter is likely to occur, and the viscosity of the slag decreases, resulting in poor bead shape. Alumina, potassium feldspar and the like can be used as Al 2 O 3 .
[0013]
Metal fluoride is a component that adjusts the melting point of slag, forms a slag with good encapsulation and peeling properties, and improves the bead shape . If it exceeds 0.5%, the melting point of the slag is remarkably lowered, the molten metal sags in the vertical and upward welding, welding in all positions becomes difficult, and the bead shape becomes poor. Further, a large amount of fume is generated with the generation of fluorine gas. As the metal fluoride, LiF, MgF 2 , AlF 2 , K 2 Zr 2 F 6 or the like can be used, and the same effect can be obtained by using any metal fluoride.
[0014]
Next, as for the metal Ti for adjusting the alloy component, most of the metal Ti is oxidized in the arc to become TiO 2 and acts as slag, but the melting point of TiO 2 originally used as a slag forming agent is 1840 ° C. On the other hand, since the melting points are lower at 1660 ° C. for metal Ti and 1317 ° C. for Fe—Ti, slag is formed at an early point, and solidification starts early to prevent dripping of the molten metal. Therefore, vertical and upward welding are facilitated. Also, it is a component that adjusts the fluidity of the slag to form a slag with good encapsulation and releasability and improves the bead shape. The molten metal during directional welding tends to sag, making it difficult to weld and causing poor bead shape.
[0015]
However, when a large amount of metal Ti was contained, the tendency for the elongation of the deposited metal to decrease was observed. In a duplex stainless steel in which the amount of ferrite of the deposited metal exceeds 25%, as shown in FIG. 1, when a large amount of hydrogen is contained in the deposited metal, hydrogen embrittlement occurs, and the elongation is significantly reduced in a tensile test of the deposited metal.
[0016]
The inventors of the present invention have focused on the amount of hydrogen and the amount of Ti in the deposited metal, and as a result, as shown in FIG. 2, the amount of hydrogen in the deposited metal has a relationship with Ti. It was found that as the value) increased, the amount of hydrogen in the deposited metal also increased.
[0017]
This is considered to be because Ti hinders the diffusion of hydrogen and fixes it. Therefore, in order to ensure ductility, it is necessary to suppress hydrogen as much as possible in order not to cause hydrogen embrittlement, and for that purpose, it is necessary to limit the amount of Ti in the wire.
[0018]
Therefore, the content of metal Ti in the wire is set to 0.44% or less based on the total weight of the wire in terms of Ti. Therefore, the metal Ti (in terms of Ti) is set to 0.08 to 0.44% by weight based on the total weight of the wire. As a Ti source, metal Ti, Fe-Ti, or the like can be used.
[0019]
Next, the total amount of the slag agent component and the flux filling rate will be described. The slag agent component in the flux forms a slag having good encapsulation and peeling properties, and improves the bead shape. If the total of the slag agent components is less than 7.3% in total, the molten metal cannot be sufficiently held in the vertical and upward welding, making welding difficult and resulting in poor bead shape. Furthermore, the encapsulation property and peelability of the slag become insufficient, slag seizure occurs, and the slag peelability decreases. If the content exceeds 11.1%, spatter increases, and slag becomes excessive, resulting in slag entrainment defects. The slag agent component in the present invention means nonmetal components such as oxides and fluorides, and P and S as impurities.
[0020]
If the flux filling rate of the stainless steel shell is less than 18%, the thickness of the shell is large, droplets are enlarged, and spatter is increased. If it exceeds 26%, on the contrary, the thickness of the outer skin is thin, and the number of disconnections frequently occurs during the wire drawing, which significantly lowers the production efficiency.
[0021]
In addition, the filling flux adjusts the alloy component according to the duplex stainless steel plate component to be welded. Ni, Cr, Mn, Mo, Si, Fe, Ti, Al, stainless powder, metal nitride, or the like is used as an adjusting agent. Further, the material may be granulated with a fixing agent depending on the raw material particle size, the flux component, the filling method, and the like. In this case, components obtained from the fixing agent, for example, in the case of water glass, SiO 2 , Na 2 O , K 2 O and the like must be mixed in advance so as to take into account the increase.
[0022]
The flux-cored wire of the present invention is a wire having a cross-sectional shape as shown in FIGS. 3A to 3D and made of an austenitic or austenitic-ferritic stainless steel pipe or strip steel. The outer shell 1 may be wrapped with the filling
[0023]
【Example】
Using austenitic or austenitic-ferritic stainless steel pipes and steel strips having the components shown in Table 1, the flux shown in Tables 2 and 3 was changed in the filling rate with respect to the total weight of the wire to obtain a stainless steel having a wire diameter of 1.2 mm. A flux cored wire for welding was manufactured. The pipe was drawn to a diameter at which the flux entered a predetermined filling rate, and then filled with the flux. In Tables 2 and 3, wire no. Nos. 1 to 13 are flux-cored wires of the present invention; 14 to 27 are comparative examples.
[0024]
[Table 1]
[0025]
[Table 2]
[0026]
[Table 3]
[0027]
The evaluation of welding workability was performed by semi-automatic welding under the welding conditions of a current of 160 A (DCEP), a voltage of 24 V, and a shielding gas of 100% CO 2 : 20 liter / min.
[0028]
The test steel sheets were assembled in a T-shape using SUS329J3L steel sheets having the components shown in Table 1, and one-sided one-pass vertical welding was performed to confirm. Further, the weld bead was cut, and the presence or absence of a slag entrapment defect in the cross section was confirmed. The workability evaluation was evaluated as ○ when practically good, and × when practically problematic. When the welding workability was all good, a JISZ3323 / A1 test piece was sampled and subjected to a tensile test. Judgment was evaluated as poor when there was a problem in welding workability, when elongation according to the AWS standard did not satisfy 20% or more in a tensile test, and when slag entrainment occurred. Table 4 shows the results.
[0029]
[Table 4]
[0030]
The wire Nos. 1 , 3, 6 to 8 and wire no. Nos. 10 to 13 are filled with an appropriate amount of a flux containing a proper amount of TiO 2 , SiO 2 , Al 2 O 3 , an F-converted value of metal fluoride, a Ti-converted value of metal Ti, and a slag agent component in an appropriate amount in a stainless steel shell. Therefore, the welding workability and the tensile test of the weld metal were good, and the results were extremely good without lowering the production efficiency.
[0031]
Wire No. in the comparative example. In No. 14, since the amount of TiO 2 was large, spatter occurred frequently, and welding workability was deteriorated. In addition, the fluidity of the slag deteriorated, and the bead shape became poor. In addition, slag entrainment defects occurred.
[0032]
Wire No. In No. 15, since the amount of TiO 2 was small, the arc state became unstable, and the encapsulating property and peeling property of the slag became poor. Furthermore, the molten metal during welding dripped, and the bead shape became defective.
[0033]
Wire No. In No. 16, the slag flowed easily due to the large amount of SiO 2 , the molten metal during welding dripped, and the bead shape was poor. Furthermore, slag seizure occurred, and the slag peelability deteriorated.
[0034]
Wire No. In No. 17, since the amount of SiO 2 was small, the fluidity of the slag was poor, and the bead shape was poor.
[0035]
Wire No. In No. 18, spatter occurred frequently because of a large amount of Al 2 O 3 . Further, the viscosity of the slag was reduced, and the bead shape was poor.
[0036]
Wire No. In No. 19, since the amount of Al 2 O 3 was small, slag flowed easily, the molten metal during welding dripped, and the bead shape was poor. In addition, the slag was poor in encapsulation, causing seizure, and the slag peelability was poor.
[0037]
Wire No. In No. 20, since the F-converted value of the metal fluoride was large, the amount of generated fluorine gas was excessive and the amount of generated welding fume was increased. In addition, the melting point of the slag was lowered, the molten metal during welding was dripped, and the bead shape was poor.
[0038]
Wire No. In No. 21, since the F conversion value of the metal fluoride was small, the slag was not uniformly covered with the weld metal, the slag was seized, and the slag peelability was poor.
[0039]
Wire No. Sample No. 22 had good welding workability because the Ti content of the metal Ti amount was large, but the elongation did not satisfy the AWS standard of 20% or more in the tensile test of the deposited metal.
[0040]
Wire No. In Sample No. 23, since the Ti-converted value of the metal Ti amount was small, the slag solidification was slow and the molten metal during welding dripped, making welding in all positions difficult, and the bead shape was also poor.
[0041]
Wire No. In No. 24, since the total amount of the slag agent components was large, spatter increased, and a defect of slag entrainment occurred.
[0042]
Wire No. In No. 25, since the total amount of the slag agent components was small, the molten metal could not be held sufficiently in vertical and upward welding, welding was difficult, and the bead shape was poor. Furthermore, the encapsulation property of the slag was insufficient, the slag was seized, and the slag peeling was poor.
[0043]
Wire No. In No. 26, since the flux filling rate was high, disconnection frequently occurred during wire drawing, and the production efficiency was significantly reduced. Therefore, drawing was not performed up to a wire diameter of 1.2 mm.
[0044]
Wire No. In No. 27, since the flux filling rate was low, droplets were enlarged and spatter increased.
[0045]
【The invention's effect】
As described in detail above, the flux-cored wire for duplex stainless steel welding of the present invention is capable of satisfying mechanical performance in welding duplex stainless steel while maintaining the arc state, the amount of spatter generated, the slag encapsulation / peelability, etc. It is useful as a flux-cored wire for duplex stainless steel welding with excellent workability in all positions.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the elongation of a deposited metal and the amount of hydrogen in the deposited metal.
FIG. 2 is a diagram showing the relationship between the amount of hydrogen in a deposited metal and the amount of Ti (in terms of Ti) in a wire.
FIG. 3 is a cross-sectional view of a flux-cored wire.
[Explanation of symbols]
1
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CN102019518A (en) * | 2010-12-31 | 2011-04-20 | 上海狮百盛焊材科技有限公司 | Two phase stainless steel welding rod |
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JP3765771B2 (en) | 2002-04-23 | 2006-04-12 | 株式会社神戸製鋼所 | Stainless steel arc welding flux cored wire |
CN101367161B (en) * | 2007-08-18 | 2011-07-20 | 中国船舶重工集团公司第七二五研究所 | Low-hydrogen super diphasic stainless steel electrode |
KR101065996B1 (en) * | 2008-05-27 | 2011-09-19 | 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 | Flux-embedded wire for welding 2 � stainless steel with fine grain solidification |
CN104668814B (en) * | 2015-02-12 | 2016-12-07 | 西安理工大学 | 2505 phase stainless steel use Self-protecting flux-cored wires and preparation method thereof |
CN106271194A (en) * | 2015-05-12 | 2017-01-04 | 海宁瑞奥金属科技有限公司 | Nickel-saving type phase stainless steel use flux-cored wire |
CN110170770A (en) * | 2019-07-03 | 2019-08-27 | 南京工业大学 | A kind of two phase stainless steel welding activating agent and welding method |
JP7469597B2 (en) | 2020-01-10 | 2024-04-17 | 日本製鉄株式会社 | Flux-cored wire and method for manufacturing welded joint |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN102019518A (en) * | 2010-12-31 | 2011-04-20 | 上海狮百盛焊材科技有限公司 | Two phase stainless steel welding rod |
CN102019518B (en) * | 2010-12-31 | 2012-12-19 | 上海狮百盛焊材科技有限公司 | Two phase stainless steel welding rod |
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