JP7638593B2 - Flux-cored wire for gas shielded arc welding - Google Patents
Flux-cored wire for gas shielded arc welding Download PDFInfo
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- JP7638593B2 JP7638593B2 JP2021050622A JP2021050622A JP7638593B2 JP 7638593 B2 JP7638593 B2 JP 7638593B2 JP 2021050622 A JP2021050622 A JP 2021050622A JP 2021050622 A JP2021050622 A JP 2021050622A JP 7638593 B2 JP7638593 B2 JP 7638593B2
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- 238000003466 welding Methods 0.000 title claims description 128
- 230000004907 flux Effects 0.000 claims description 40
- 229910000831 Steel Inorganic materials 0.000 claims description 38
- 239000010959 steel Substances 0.000 claims description 38
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 18
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 13
- 229910052749 magnesium Inorganic materials 0.000 claims description 12
- 229910001512 metal fluoride Inorganic materials 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- 229910052681 coesite Inorganic materials 0.000 claims description 7
- 229910052906 cristobalite Inorganic materials 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- 235000012239 silicon dioxide Nutrition 0.000 claims description 7
- 229910052682 stishovite Inorganic materials 0.000 claims description 7
- 229910052905 tridymite Inorganic materials 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 4
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 description 71
- 239000002184 metal Substances 0.000 description 71
- 239000011734 sodium Substances 0.000 description 19
- 239000010949 copper Substances 0.000 description 17
- 239000002893 slag Substances 0.000 description 17
- 239000011324 bead Substances 0.000 description 16
- 229910052710 silicon Inorganic materials 0.000 description 16
- 239000007787 solid Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 14
- 230000007547 defect Effects 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 9
- 239000000956 alloy Substances 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 229910052748 manganese Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 229910052719 titanium Inorganic materials 0.000 description 8
- 229910052796 boron Inorganic materials 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 7
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 229910052750 molybdenum Inorganic materials 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 229910004298 SiO 2 Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 235000019353 potassium silicate Nutrition 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 3
- 229910002551 Fe-Mn Inorganic materials 0.000 description 2
- 229910017082 Fe-Si Inorganic materials 0.000 description 2
- 229910002593 Fe-Ti Inorganic materials 0.000 description 2
- 229910017133 Fe—Si Inorganic materials 0.000 description 2
- 239000004111 Potassium silicate Substances 0.000 description 2
- 229910006639 Si—Mn Inorganic materials 0.000 description 2
- DLHONNLASJQAHX-UHFFFAOYSA-N aluminum;potassium;oxygen(2-);silicon(4+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Al+3].[Si+4].[Si+4].[Si+4].[K+] DLHONNLASJQAHX-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000003517 fume Substances 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 229910052913 potassium silicate Inorganic materials 0.000 description 2
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 229910018134 Al-Mg Inorganic materials 0.000 description 1
- 229910016569 AlF 3 Inorganic materials 0.000 description 1
- 229910018467 Al—Mg Inorganic materials 0.000 description 1
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910018594 Si-Cu Inorganic materials 0.000 description 1
- 229910008423 Si—B Inorganic materials 0.000 description 1
- 229910008465 Si—Cu Inorganic materials 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052652 orthoclase Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- GROMGGTZECPEKN-UHFFFAOYSA-N sodium metatitanate Chemical compound [Na+].[Na+].[O-][Ti](=O)O[Ti](=O)O[Ti]([O-])=O GROMGGTZECPEKN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Nonmetallic Welding Materials (AREA)
Description
本発明は、低入熱の溶接条件から大入熱・高パス間温度の高能率の溶接条件で溶接をしても、良好な機械的性質を有する溶接金属を得ることができ、高電流の溶接においてもアークが安定してスパッタ発生量が少なく溶接作業性に優れるガスシールドアーク溶接用フラックス入りワイヤに関する。 The present invention relates to a flux-cored wire for gas-shielded arc welding that can produce weld metal with good mechanical properties even when welding under conditions ranging from low heat input to high heat input and high interpass temperature, and that has a stable arc even when welding with a high current, with little spatter generation and excellent welding workability.
造船及び建築鉄骨等の分野では、鋼構造物の高能率な溶接施工法としてソリッドワイヤを用いたガスシールドアーク溶接が多用されている。適用される溶接条件は高電流で３０～４０ｋＪ／ｃｍの大入熱溶接となり、さらに、各溶接パスの時間を短くしてなるべく連続的に溶接を行おうとすると、高パス間温度となる。近年、さらなる溶接効率向上のため、さらに４０ｋＪ／ｃｍを超える大入熱・高パス間温度での溶接に移行しつつあるが、溶接金属には所定の強度と靭性を有することが必要である。しかしながらこのような大入熱、高パス間温度で溶接した場合、溶接金属の機械的性質は劣化する傾向にあり、健全な溶接継手が得られないとともに、ガスシールドアーク溶接用ソリッドワイヤを用いて高電流で溶接をすると大粒のスパッタが多く発生し、溶接作業性も著しく劣化するという問題がある。 In the fields of shipbuilding and steel building, gas-shielded arc welding using solid wire is widely used as a highly efficient welding method for steel structures. The welding conditions applied are high current and high heat input of 30 to 40 kJ/cm. Furthermore, if the time of each welding pass is shortened to perform welding as continuously as possible, the interpass temperature becomes high. In recent years, in order to further improve welding efficiency, there has been a shift to welding with a high heat input of more than 40 kJ/cm and high interpass temperature, but the weld metal needs to have a certain strength and toughness. However, when welding with such a high heat input and high interpass temperature, the mechanical properties of the weld metal tend to deteriorate, making it difficult to obtain a sound welded joint, and there are problems in that welding with a high current using a solid wire for gas-shielded arc welding generates a lot of large spatter and significantly deteriorates welding workability.
これらの問題を解決する手段として、大入熱・高パス間温度での溶接において、優れた機械的性質を有する溶接金属を得られる溶接用ソリッドワイヤとして、Ｔｉ－Ｂ系の溶接材料の提案がいくつかなされている。例えば、特許文献１には、Ｃ、Ｓｉ、Ｍｎ、Ｔｉ及びＭｇまたはＡｌの１種類以上を含有し、Ｂ、Ｃｕ、Ｎｉ、Ｃｒ、Ｍｏを所定量含む溶接用ソリッドワイヤの提案がされている。 As a means of solving these problems, several Ti-B based welding materials have been proposed as welding solid wires that can produce weld metal with excellent mechanical properties when welding with large heat input and high interpass temperatures. For example, Patent Document 1 proposes a welding solid wire that contains one or more of C, Si, Mn, Ti, and Mg or Al, and also contains specified amounts of B, Cu, Ni, Cr, and Mo.
また、特許文献２には、Ｃ、Ｓｉ、Ｍｎ，Ｔｉ、Ａｌ、Ｃｕ、Ｍｏ、Ｂを含有し、さらにＮｉを所定量含有し、Ｎを一定量以下に制限し、さらにＫを所定量含む溶接用ソリッドワイヤが提案されている。しかし、これら特許文献１及び特許文献２に開示された溶接用ソリッドワイヤは、溶接入熱量が４０ｋｊ／ｃｍまでの大入熱・高パス間溶接条件で溶接した場合、溶接金属の強度および靭性は優れた性質を得られるが、横向姿勢溶接等の溶接入熱量２０ｋＪ／ｃｍ程度の低入熱の溶接条件の場合、溶接金属は強度が過多になるなど、所定の機械的性質を満足できない。 Patent Document 2 proposes a welding solid wire that contains C, Si, Mn, Ti, Al, Cu, Mo, and B, a specified amount of Ni, N limited to a certain amount or less, and a specified amount of K. However, the welding solid wires disclosed in Patent Documents 1 and 2 provide excellent strength and toughness of the weld metal when welded under high heat input and high interpass welding conditions with a welding heat input of up to 40 kJ/cm, but when welded under low heat input welding conditions with a welding heat input of about 20 kJ/cm, such as horizontal position welding, the weld metal has excessive strength and does not satisfy the specified mechanical properties.
また、特許文献３には、Ｃ、Ｓｉ、Ｍｎ、Ｍｏ、Ｔｉ、Ｂ、Ｃｕ、Ｎｉ及びＣｒを適量含有することによって、低入熱から高入熱・高パス間温度の溶接を行っても溶接金属の強度及び靭性が得られる溶接用ソリッドワイヤの開示がある。しかし、特許文献３に開示された溶接用ソリッドワイヤにおいても溶接入熱量が４０ｋＪ／ｃｍを超える大入熱で高パス間温度の溶接条件においては、溶接金属の強度及び靭性が得られず、溶接時のスパッタ発生量が多くなるという問題がある。 Patent Document 3 discloses a solid wire for welding that contains appropriate amounts of C, Si, Mn, Mo, Ti, B, Cu, Ni, and Cr, thereby obtaining strength and toughness of the weld metal even when welding is performed with low to high heat input and high interpass temperature. However, even with the solid wire for welding disclosed in Patent Document 3, there is a problem that the strength and toughness of the weld metal cannot be obtained under welding conditions of high heat input and high interpass temperature, where the welding heat input exceeds 40 kJ/cm, and the amount of spatter generated during welding is large.
高電流での溶接で問題となる、スパッタ発生量が少ないガスシールドアーク溶接用ソリッドワイヤの開発が行われており、例えば特許文献４には、希土類元素を含有し、ワイヤ表面に固形潤滑剤を有し、さらに固形潤滑剤の外周面に液体潤滑剤皮膜を有することによって、スパッタ発生量が少なく、かつワイヤ送給性を良好にする技術が開示されている。 Solid wires for gas-shielded arc welding that generate less spatter, a problem that occurs when welding with high currents, have been developed. For example, Patent Document 4 discloses a technology that contains rare earth elements, has a solid lubricant on the wire surface, and further has a liquid lubricant coating on the outer periphery of the solid lubricant, thereby reducing the amount of spatter generated and improving wire feedability.
また、特許文献５には、２種類以上のアルカリ金属を含侵させたアルカリ金属含侵部をワイヤ表層下に形成させることによってスパッタ発生量を低減できるガスシールドアーク溶接用ソリッドワイヤが開示されている。しかし、ガスシールドアーク溶接用ソリッドワイヤを用いた大電流溶接では、発生するスパッタ自体が多いので、たとえワイヤ送給性が良好になってもスパッタ発生量を十分に低減できず、またビード外観・形状も改善できないという問題があった。 Patent Document 5 discloses a solid wire for gas-shielded arc welding that can reduce the amount of spatter generated by forming an alkali metal-impregnated portion impregnated with two or more types of alkali metals under the wire surface. However, in high-current welding using a solid wire for gas-shielded arc welding, a large amount of spatter is generated, so even if the wire feedability is improved, the amount of spatter generated cannot be sufficiently reduced, and the bead appearance and shape cannot be improved.
一方、大入熱・高パス間温度の溶接施工条件で溶接金属の強度及び靭性を確保しつつ、溶接作業性が良好なガスシールドアーク溶接用フラックス入りワイヤとして、例えば特許文献６や特許文献７には、大入熱・高パス間温度の溶接施工条件の下で、良好な溶接作業性が得られるとともに、機械的性質が優れた溶接金属が得られるフラックス入りワイヤが開示されている。しかし、これらのフラックス入りワイヤにおいても、溶接入熱量が４０ｋＪ／ｃｍを超える高入熱で高パス間温度の溶接施工条件では溶接金属の強度及び靭性が得られないという問題があった。また、後者はスラグ生成量も多くなるので、スラグ巻き込みなどの溶接欠陥が発生しやすくなるという問題があった。 On the other hand, as a flux-cored wire for gas-shielded arc welding that ensures the strength and toughness of the weld metal under welding conditions of high heat input and high interpass temperature and provides good welding workability, for example, Patent Documents 6 and 7 disclose flux-cored wires that provide good welding workability under welding conditions of high heat input and high interpass temperature and that provide weld metal with excellent mechanical properties. However, even with these flux-cored wires, there is a problem that the strength and toughness of the weld metal cannot be obtained under welding conditions of high heat input and high interpass temperature where the welding heat input exceeds 40 kJ/cm. In addition, the latter also generates a large amount of slag, which makes welding defects such as slag entrapment more likely to occur.
そこで本発明は、上述した問題点に鑑みて案出されたものであり、溶接入熱量２０ｋＪ／ｃｍ程度の低入熱の溶接条件から溶接入熱量６０ｋＪ／ｃｍの大入熱で高パス間温度のような高能率の溶接条件で溶接をしても、溶接欠陥が生じることなく良好な機械的性質を有する溶接金属を得ることができ、高電流の溶接でもアークが安定してスパッタ発生量が少なく溶接作業性に優れるガスシールドアーク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。 The present invention was devised in consideration of the above-mentioned problems, and aims to provide a flux-cored wire for gas-shielded arc welding that can produce weld metal with good mechanical properties without causing welding defects, even when welding under welding conditions ranging from low heat input of about 20 kJ/cm to high heat input of 60 kJ/cm and high interpass temperatures, and that has a stable arc even with high current welding, low spatter generation, and excellent welding workability.
本発明者らは、溶接入熱量２０ｋＪ／ｃｍ程度の低入熱の溶接条件から溶接入熱量６０ｋＪ／ｃｍの大入熱で高パス間温度のような高能率の溶接条件で溶接をしても、溶接欠陥が生じることなく良好な機械的性質を有する溶接金属を得ることができ、高電流の溶接でもアークが安定してスパッタ発生量が少ない等の溶接作業性に優れるガスシールドアーク溶接用フラックス入りワイヤの成分組成について詳細に検討した。 The inventors conducted a detailed study on the composition of flux-cored wire for gas-shielded arc welding, which has excellent welding workability, such as a stable arc and low spatter generation even with high current welding, and can produce weld metal with good mechanical properties without welding defects, even when welding under low heat input conditions of about 20 kJ/cm to high heat input of 60 kJ/cm and high efficiency welding conditions such as high interpass temperatures.
その結果、溶接入熱量２０ｋＪ／ｃｍ程度の低入熱の溶接条件、高電流の溶接施工条件及び溶接入熱量６０ｋＪ／ｃｍの大入熱・高パス間温度の溶接施工条件においても溶接欠陥が生じることなく、溶接金属の適正な強度と安定した靱性を達成するためには、ワイヤ中のスラグ生成剤である酸化物を極力減らし、合金成分のＣ、Ｓｉ、Ｍｎ、Ｃｕ及びＴｉのそれぞれの適量化が有効であることを見出した。 As a result, it was found that in order to achieve appropriate strength and stable toughness of the weld metal without the occurrence of welding defects even under low heat input welding conditions of about 20 kJ/cm, high current welding conditions, and high heat input and high interpass temperature welding conditions of 60 kJ/cm, it is effective to minimize oxides, which are slag generating agents in the wire, and to optimize the amounts of each of the alloy components C, Si, Mn, Cu, and Ti.
また、ワイヤ中のＭｏ、Ｂ量を適量にすることにより、溶接入熱量６０ｋＪ／ｃｍの大入熱で高パス間温度の溶接施工条件においても、溶接金属の靱性を低下させることなく所定の引張強さを有する溶接金属を得られることを見出した。 It was also discovered that by adjusting the amount of Mo and B in the wire to an appropriate level, it is possible to obtain weld metal with a specified tensile strength without reducing the toughness of the weld metal, even under welding conditions with a high heat input of 60 kJ/cm and high interpass temperatures.
さらに、ワイヤ中のＡｌ及びＭｇを適量にすることにより、溶接金属の靭性をさらに良好にすることも見出した。 Furthermore, it was discovered that the toughness of the weld metal can be further improved by adjusting the amount of Al and Mg in the wire.
また、溶接作業性は、Ｃ、Ｔｉ、金属弗化物のＦ換算値の合計及びＮａ酸化物及びＫ酸化物のＮａ２Ｏ換算値とＫ２Ｏ換算値の合計を適量とすることでアークを安定化させてスパッタ発生量を低減させ、Ｓｉ酸化物のＳｉＯ２換算値の合計を適量とすることでビード外観・形状を良好にできることを見出した。 In addition, it was found that, in terms of welding workability, the arc can be stabilized and the amount of spatter generated can be reduced by setting the total of the F-equivalent values of C, Ti, and metal fluorides, and the total of the Na2O -equivalent values and K2O-equivalent values of Na oxides and K oxides to appropriate amounts, and that the appearance and shape of the bead can be improved by setting the total of the SiO2 - equivalent values of Si oxides to an appropriate amount.
すなわち、本発明の要旨は、鋼製外皮にフラックスを充填してなるガスシールドアーク溶接用フラックス入りワイヤにおいて、ワイヤ全質量に対する質量％で、鋼製外皮とフラックスの合計で、Ｃ：０．０４～０．１０％、Ｓｉ：０．４～１．４％、Ｍｎ：１．７～２．５％未満、Ｍｏ：０．６～１．０％、Ｃｕ：０．０５～０．５％、Ｔｉ：０．１～０．４％、Ｂ：０．００１５～０．０１０％を含有し、さらに、ワイヤ全質量に対する質量％で、フラックス中に、金属弗化物：Ｆ換算値の合計で０．００５～０．１０％、Ｓｉ酸化物：ＳｉＯ２換算値の合計で０．０１～０．２％、Ｎａ酸化物及びＫ酸化物の１種または２種以上：Ｎａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．０２～０．１４％を含有し、残部が鋼製外皮のＦｅ、成分調整のために添加する鉄粉、鉄合金粉のＦｅ分及び不可避不純物からなることを特徴とする。 That is, the gist of the present invention is a flux-cored wire for gas shielded arc welding, which is made by filling a steel sheath with flux, and which contains, in mass % relative to the total mass of the wire, the total of the steel sheath and flux, C: 0.04 to 0.10%, Si: 0.4 to 1.4%, Mn: 1.7 to less than 2.5%, Mo: 0.6 to 1.0%, Cu: 0.05 to 0.5%, Ti: 0.1 to 0.4%, and B: 0.0015 to 0.010%, and further contains, in mass % relative to the total mass of the wire, metal fluorides: F conversion value of 0.005 to 0.10%, Si oxides: SiO2 conversion value of 0.01 to 0.2%, Na oxides and K oxides: Na2O conversion value and K2O conversion value of 0.01 to 0.2%, and one or more of Na oxides and K oxides: Na2O conversion value and K2O conversion value of 0.01 to 0.2%. The steel contains 0.02 to 0.14% in total calculated as O, with the remainder consisting of Fe from the steel sheath, iron powder added for adjusting the composition, Fe from the iron alloy powder, and unavoidable impurities.
また、ワイヤ全質量に対する質量％で、鋼製外皮とフラックスの合計で、Ａｌ及びＭｇの一方または両方の合計：０．２５％以下をさらに含有することも特徴とするガスシールドアーク溶接用フラックス入りワイヤにある。 The flux-cored wire for gas-shielded arc welding is also characterized in that it further contains, in mass percent relative to the total mass of the wire, 0.25% or less of either or both of Al and Mg, in the total of the steel sheath and flux.
本発明のガスシールドアーク溶接用フラックス入りワイヤによれば、溶接入熱量２０ｋＪ／ｃｍ程度の低入熱の溶接条件から溶接入熱量６０ｋＪ／ｃｍの大入熱で高パス間温度のような高能率の溶接施工条件で溶接をしても、溶接欠陥が生じることなく良好な機械的性質を有する溶接金属を得ることができ、高電流の溶接でもアークが安定してスパッタ発生量が少なく、ビード外観・形状が良好であるなどの溶接作業性に優れる等、高品質な溶接部を高能率に得ることができる。 The flux-cored wire for gas-shielded arc welding of the present invention can produce weld metal with good mechanical properties without any welding defects, even when welding is performed under conditions ranging from low heat input of about 20 kJ/cm to high heat input of 60 kJ/cm and high interpass temperatures, and can produce high-quality welds with high efficiency, such as excellent welding workability with a stable arc and low spatter generation even with high current welding, and good bead appearance and shape.
以下、本発明を適用したガスシールドアーク溶接用フラックス入りワイヤの成分組成及びその含有量と、各成分組成の限定理由とについて説明する。なお、各成分組成の含有量は、質量％で表すものとし、その質量％に関する記載を単に％と記載して表すこととする。 The following describes the composition and content of the flux-cored wire for gas-shielded arc welding to which the present invention is applied, and the reasons for limiting the composition of each component. The content of each component is expressed in mass%, and the description of the mass% is simply written as %.
［鋼製外皮とフラックスの合計でＣ：０．０４～０．１０％］
Ｃは、溶接金属の強度を向上させる効果がある。Ｃが０．０４％未満であると、大入熱・高パス間温度の溶接施工条件で十分な溶接金属の強度が得られない。一方、Ｃが０．１０％を超えると、溶接金属の強度が高くなり靱性が低下する。従って、鋼製外皮とフラックスの合計でＣは０．０４～０．１０％とする。なお、Ｃは鋼製外皮に含まれる成分の他、フラックスから金属粉及び合金粉末等から添加できる。
[Steel sheath and flux combined C: 0.04-0.10%]
C has the effect of improving the strength of the weld metal. If C is less than 0.04%, sufficient weld metal strength cannot be obtained under welding conditions of large heat input and high interpass temperature. On the other hand, if C exceeds 0.10%, the strength of the weld metal increases but the toughness decreases. Therefore, the total C content of the steel sheath and flux is set to 0.04 to 0.10%. Note that C can be added from the components contained in the steel sheath, as well as from the flux, metal powder, alloy powder, etc.
［鋼製外皮とフラックスの合計でＳｉ：０．４～１．４％］
Ｓｉは、脱酸剤であり溶接金属の酸素量を調整する。またＳｉは、溶接金属の強度を向上させる効果がある。Ｓｉが０．４％未満であると、脱酸不足となり溶接金属の強度が低く、靱性が低下する。一方、Ｓｉが１．４％を超えると、溶接金属の強度が過剰に高くなり、靱性が安定して得られない。またＳｉが１．４％を超えると、溶接時に生成するスラグ量が増加してスラグ巻込み等の溶接欠陥が発生しやすくなる。従って、鋼製外皮とフラックスの合計でＳｉは０．４～１．４％とする。なお、Ｓｉは鋼製外皮に含まれる成分の他、フラックスから金属Ｓｉ、Ｆｅ－Ｓｉ、Ｆｅ－Ｓｉ－Ｍｎ等の合金粉末から添加できる。
[Si: 0.4-1.4% in total for steel sheath and flux]
Silicon is a deoxidizer and adjusts the amount of oxygen in the weld metal. Silicon also has the effect of improving the strength of the weld metal. If the amount of silicon is less than 0.4%, the deoxidation is insufficient, resulting in low strength of the weld metal and reduced toughness. On the other hand, if the amount of silicon exceeds 1.4%, the strength of the weld metal becomes excessively high, and the toughness cannot be obtained stably. If the amount of silicon exceeds 1.4%, the amount of slag generated during welding increases, and welding defects such as slag inclusion tend to occur. Therefore, the total amount of silicon in the steel sheath and the flux is set to 0.4 to 1.4%. In addition to the components contained in the steel sheath, silicon can be added from the flux as metal silicon, Fe-Si, Fe-Si-Mn, or other alloy powders.
［鋼製外皮とフラックスの合計でＭｎ：１．７～２．５％未満］
Ｍｎは、大入熱・高パス間温度の溶接施工条件で溶接金属の靱性及び強度を向上させる効果がある。Ｍｎが１．７％未満であると、大入熱・高パス間温度の溶接施工条件で溶接金属の強度が低くなり靱性が低下する。一方、Ｍｎが２．５％以上になると、低入熱の溶接施工で溶接金属の強度が高くなり、靱性が安定して得られない。また、Ｍｎが２．５％以上になると、低入熱及び大入熱・高パス間温度の溶接条件共にスラグ量が多くなり、スラグ巻込み等の溶接欠陥が発生しやすくなる。従って、鋼製外皮とフラックスの合計でＭｎは１．７～２．５％未満とする。なお、Ｍｎは、鋼製外皮に含まれる成分の他、金属Ｍｎ、Ｆｅ－Ｍｎ、Ｆｅ－Ｓｉ－Ｍｎ等の合金粉末から添加できる。
[Mn: 1.7-2.5% in total for steel sheath and flux]
Mn has the effect of improving the toughness and strength of the weld metal under welding conditions of large heat input and high interpass temperature. If the Mn content is less than 1.7%, the strength of the weld metal is low under welding conditions of large heat input and high interpass temperature, and the toughness is reduced. On the other hand, if the Mn content is 2.5% or more, the strength of the weld metal is high in low heat input welding, and the toughness cannot be obtained stably. In addition, if the Mn content is 2.5% or more, the amount of slag increases under both low heat input and high heat input and high interpass temperature welding conditions, and welding defects such as slag inclusion are likely to occur. Therefore, the total Mn content of the steel sheath and the flux is set to 1.7 to less than 2.5%. Note that Mn can be added from alloy powder such as metal Mn, Fe-Mn, Fe-Si-Mn, etc., in addition to the components contained in the steel sheath.
［鋼製外皮とフラックスの合計でＭｏ：０．６～１．０％］
Ｍｏは、Ｍｎが前述の範囲内で、大入熱・高パス間温度の溶接施工条件において、溶接金属の強度を確保するうえで重要である。Ｍｏが０．６％未満であると、大入熱・高パス間温度の溶接施工条件で溶接金属の強度が低くなる。一方、Ｍｏが１．０％を超えると、低入熱の溶接施工条件で溶接金属の強度が過剰に高くなり、靭性が安定して得られない。従って、鋼製外皮とフラックスの合計でＭｏは０．６～１．０％とする。なお、Ｍｏは、鋼製外皮に含まれる成分の他、フラックスからの金属Ｍｏ粉から添加できる。
[Mo: 0.6-1.0% in total for steel sheath and flux]
Mo is important for ensuring the strength of the weld metal under welding conditions of large heat input and high interpass temperature when Mn is within the above-mentioned range. If Mo is less than 0.6%, the strength of the weld metal will be low under welding conditions of large heat input and high interpass temperature. On the other hand, if Mo exceeds 1.0%, the strength of the weld metal will be excessively high under welding conditions of low heat input, and toughness will not be stably obtained. Therefore, the total Mo content of the steel sheath and flux is set to 0.6 to 1.0%. Note that Mo can be added from the components contained in the steel sheath, as well as from metallic Mo powder from the flux.
［鋼製外皮とフラックスの合計でＣｕ：０．０５～０．５％］
Ｃｕは、析出強化作用を有し、変態温度を低下させ溶接金属の組織を微細化して靭性を安定させる効果がある。Ｃｕが０．０５％未満であると、この効果が得られず、安定した溶接金属の靭性が得られない。一方、Ｃｕが０．５％を超えると、析出脆化が生じて溶接金属の靭性が低下し、また高温割れが生じやすくなる。従って、鋼製外皮とフラックスの合計でＣｕは０．０５～０．５％とする。なお、Ｃｕは、鋼製外皮に含まれる成分及び鋼製外皮表面に施したＣｕめっき分の他、フラックスからの金属Ｃｕ、Ｆｅ－Ｓｉ－Ｃｕ等の合金粉から添加できる。
[Cu: 0.05-0.5% in total for steel sheath and flux]
Cu has a precipitation strengthening effect, lowers the transformation temperature, refines the structure of the weld metal, and stabilizes the toughness. If Cu is less than 0.05%, this effect cannot be obtained, and stable toughness of the weld metal cannot be obtained. On the other hand, if Cu exceeds 0.5%, precipitation embrittlement occurs, the toughness of the weld metal decreases, and hot cracking becomes more likely to occur. Therefore, the total Cu content of the steel sheath and the flux is set to 0.05 to 0.5%. Cu can be added from the components contained in the steel sheath and the Cu plating applied to the surface of the steel sheath, as well as from metallic Cu from the flux and alloy powder such as Fe-Si-Cu.
［鋼製外皮とフラックスの合計でＴｉ：０．１～０．４％］
Ｔｉは、特に高電流での溶接及び大入熱・高パス間温度での溶接施工時にアークを安定にし、脱酸剤として作用するとともに、溶接金属中にＴｉの微細酸化物を生成し溶接金属の靭性をより向上させる効果がある。Ｔｉが０．１％未満であると、この効果が得られず、高電流での溶接及び大入熱・高パス間温度での溶接施工時にアークが不安定になるとともに溶接金属の靭性が低下する。一方、Ｔｉが０．４％を超えると、溶接金属中にＴｉの析出物が多くなり、靭性が低下する。従って、鋼製外皮とフラックスの合計でＴｉは０．１～０．４％とする。なお、Ｔｉは、鋼製外皮に含まれる成分の他、フラックスからの金属Ｔｉ、Ｆｅ－Ｔｉ等の合金粉から添加できる。
[Ti: 0.1-0.4% in total for steel sheath and flux]
Ti stabilizes the arc, particularly during high current welding and high heat input/high interpass temperature welding, and acts as a deoxidizer, while also producing fine oxides of Ti in the weld metal, further improving the toughness of the weld metal. If Ti is less than 0.1%, this effect cannot be obtained, and the arc becomes unstable and the toughness of the weld metal decreases during high current welding and high heat input/high interpass temperature welding. On the other hand, if Ti exceeds 0.4%, Ti precipitates increase in the weld metal, decreasing the toughness. Therefore, the total Ti content of the steel sheath and the flux is set to 0.1-0.4%. In addition to the components contained in the steel sheath, Ti can be added from metallic Ti from the flux, alloy powder such as Fe-Ti, etc.
［鋼製外皮とフラックスの合計でＢ：０．００１５～０．０１０％］
Ｂは、大入熱・高パス間温度での溶接施工条件において、溶接金属の結晶粒界に生成する粒界フェライトの生成を抑制し靭性を向上させる効果がある。Ｂが０．００１５％未満であると、大入熱・高パス間温度での溶接施工条件で溶接金属の靭性が低下する。一方、Ｂが０．０１０％を超えると、高温割れが発生しやすくなる。従って、鋼製外皮とフラックスの合計でＢは０．００１５～０．０１０％とする。なお、Ｂは、鋼製外皮に含まれる成分の他、Ｆｅ－Ｓｉ－Ｂ、Ｆｅ－Ｍｎ－Ｂ等の合金粉から添加できる。
[B: 0.0015-0.010% in total for steel sheath and flux]
B has the effect of suppressing the formation of grain boundary ferrite at the grain boundaries of the weld metal and improving toughness under welding conditions of large heat input and high interpass temperature. If B is less than 0.0015%, the toughness of the weld metal decreases under welding conditions of large heat input and high interpass temperature. On the other hand, if B exceeds 0.010%, hot cracking is likely to occur. Therefore, the total B content of the steel sheath and flux is set to 0.0015 to 0.010%. Note that B can be added from alloy powders such as Fe-Si-B and Fe-Mn-B, in addition to the components contained in the steel sheath.
［フラックス中の金属弗化物：Ｆ換算値の合計：０．００５～０．１０％］
金属弗化物は、アークを集中させて安定させる効果がある。金属弗化物のＦ換算値の合計が０．００５％未満では、この効果が得られず、アークが不安定でスパッタ発生量が多くなる。一方、金属弗化物のＦ換算値の合計が０．１０％を超えると、アークが強くて不安定になり、スパッタ発生量が多くなる。従って、フラックス中に含有する金属弗化物のＦ換算値の合計は０．００５～０．１０％とする。なお、金属弗化物は、フラックスからのＣａＦ２、ＮａＦ、ＬｉＦ、ＭｇＦ２、Ｋ２ＳｉＦ６、Ｎａ３ＡｌＦ６、ＡｌＦ３等から添加でき、Ｆ換算値はそれらに含有されるＦの含有量の合計である。
[Metal fluorides in flux: Total F conversion value: 0.005-0.10%]
Metal fluorides have the effect of concentrating and stabilizing the arc. If the total F-equivalent value of the metal fluorides is less than 0.005%, this effect cannot be obtained, the arc becomes unstable, and the amount of spatter generation increases. On the other hand, if the total F-equivalent value of the metal fluorides exceeds 0.10%, the arc becomes strong and unstable, and the amount of spatter generation increases. Therefore, the total F-equivalent value of the metal fluorides contained in the flux is set to 0.005 to 0.10%. Note that metal fluorides can be added from CaF 2 , NaF, LiF, MgF 2 , K 2 SiF 6 , Na 3 AlF 6 , AlF 3, etc. from the flux, and the F-equivalent value is the total amount of F contained therein.
［フラックス中のＳｉ酸化物：ＳｉＯ２換算値の合計：０．０１～０．２％］
フラックス中のＳｉ酸化物は、溶融スラグの粘性を高めてスラグ被包性を向上させてビード止端部のなじみを良好にし、ビード外観・形状を良好にする効果がある。Ｓｉ酸化物のＳｉＯ２換算値の合計が０．０１％未満であると、溶接ビードの止端部のなじみが悪くなり、ビード外観・形状が悪くなる。一方、Ｓｉ酸化物のＳｉＯ２換算値の合計が０．２％を超えると、溶接金属中の酸素量が増加して靭性が低下する。また、Ｓｉ酸化物のＳｉＯ２換算値の合計が０．２％を超えるとスラグ量が多くなり、スラグ巻込み等の溶接欠陥が発生しやすくなる。従って、フラックス中に含有するＳｉ酸化物のＳｉＯ２換算値の合計は０．０１～０．２％とする。なお、Ｓｉ酸化物は、フラックスからの珪砂、正長石、珪酸カリウムからなる水ガラスの固質成分等から添加できる。
[Si oxide in flux: Total SiO2 equivalent: 0.01-0.2%]
The Si oxides in the flux have the effect of increasing the viscosity of the molten slag, improving the slag encapsulation, improving the conformity of the weld bead toe, and improving the bead appearance and shape. If the total of the Si oxides in terms of SiO 2 is less than 0.01%, the conformity of the weld bead toe is poor, and the bead appearance and shape are poor. On the other hand, if the total of the Si oxides in terms of SiO 2 exceeds 0.2%, the amount of oxygen in the weld metal increases and the toughness decreases. Also, if the total of the Si oxides in terms of SiO 2 exceeds 0.2%, the amount of slag increases, and welding defects such as slag inclusion are likely to occur. Therefore, the total of the Si oxides in terms of SiO 2 contained in the flux is set to 0.01 to 0.2%. The Si oxides can be added from the solid components of the water glass made of silica sand, orthoclase, and potassium silicate from the flux.
［フラックス中のＮａ酸化物及びＫ酸化物の１種または２種以上：Ｎａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．０２～０．１４％］
Ｎａ酸化物及びＫ酸化物は、アークを安定にする効果がある。Ｎａ酸化物及びＫ酸化物の１種または２種以上がＮａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．０２％未満であると、アークが不安定になり、スパッタ発生量が多くなる。一方、Ｎａ酸化物及びＫ酸化物の１種または２種以上がＮａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．１４％を超えると、アークが不安定でスパッタ発生量が多くなる。また、Ｎａ酸化物及びＫ酸化物の１種または２種以上がＮａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．１４％を超えると、溶接時に生成するスラグ量が多くなり、スラグ巻込み等の溶接欠陥が発生しやすくなる。従って、フラックス中に含有するＮａ酸化物及びＫ酸化物の１種または２種以上はＮａ２ＯとＫ２Ｏ換算値の合計で０．０２～０．１４％とする。なお、Ｎａ酸化物及びＫ酸化物は、珪酸ソーダ及び珪酸カリウムからなる水ガラスの固質成分、カリ長石、チタン酸ナトリウム等の等の粉末から添加できる。
[One or more of Na oxides and K oxides in flux: 0.02 to 0.14% in terms of Na 2 O and K 2 O in total]
Na oxide and K oxide have the effect of stabilizing the arc. If the total of one or more of Na oxide and K oxide is less than 0.02% in terms of Na 2 O and K 2 O, the arc becomes unstable and the amount of spatter generation increases. On the other hand, if the total of one or more of Na oxide and K oxide exceeds 0.14% in terms of Na 2 O and K 2 O, the arc becomes unstable and the amount of spatter generation increases. If the total of one or more of Na oxide and K oxide exceeds 0.14% in terms of Na 2 O and K 2 O, the amount of slag generated during welding increases, and welding defects such as slag inclusion are likely to occur. Therefore, the total of one or more of Na oxide and K oxide contained in the flux is set to 0.02 to 0.14% in terms of Na 2 O and K 2 O. Incidentally, Na oxide and K oxide can be added in the form of powders of solid components of water glass made of sodium silicate and potassium silicate, potassium feldspar, sodium titanate, etc.
［鋼製外皮とフラックスの合計でＡｌ及びＭｇの一方または両方：０．２５％以下］
Ａｌ及びＭｇは、強脱酸剤で溶接金属中の酸素を低減し、溶接金属の靭性を高める効果がある。しかし、Ａｌ及びＭｇの一方または両方で０．２５％を超えると、溶接時にアーク中で激しく酸化反応してヒューム発生量やスパッタ発生量が多くなる。従って、鋼製外皮とフラックスの合計でＡｌ及びＭｇの一方または両方は０．２５％以下とする。なお、溶接金属中の酸素を低減し、溶接金属の靭性を高める効果を得るために、Ａｌ及びＭｇの一方または両方は０．０５％以上であることが好ましい。Ａｌ及びＭｇは、金属Ａｌ、Ｆｅ－Ａｌ、金属Ｍｇ、Ａｌ－Ｍｇ等の合金粉から添加できる。
[Al and/or Mg in the steel sheath and flux combined: 0.25% or less]
Al and Mg are strong deoxidizers and have the effect of reducing oxygen in the weld metal and increasing the toughness of the weld metal. However, if either or both of Al and Mg exceed 0.25%, a strong oxidation reaction occurs in the arc during welding, increasing the amount of fume and spatter generation. Therefore, the total content of either or both of Al and Mg in the steel sheath and flux is set to 0.25% or less. In order to reduce oxygen in the weld metal and increase the toughness of the weld metal, it is preferable that either or both of Al and Mg are 0.05% or more. Al and Mg can be added from alloy powders such as metallic Al, Fe-Al, metallic Mg, and Al-Mg.
本発明のガスシールドアーク溶接用フラックス入りワイヤの残部は、鋼製外皮のＦｅ、成分調整のために添加する鉄粉、Ｆｅ－Ｓｉ、Ｆｅ－Ｍｎ、Ｆｅ－Ｔｉ合金などの鉄合金粉のＦｅ分及び不可避不純物である。不純物については特に規定しないが、高温割れ及び溶接金属の靱性の観点から、Ｐ：０．０３％以下、Ｓ：０．０３％以下であることが好ましい。 The remainder of the flux-cored wire for gas-shielded arc welding of the present invention is the Fe in the steel sheath, the iron powder added to adjust the composition, the Fe content of the iron alloy powder such as Fe-Si, Fe-Mn, and Fe-Ti alloys, and unavoidable impurities. There are no particular restrictions on the impurities, but from the viewpoint of hot cracking and toughness of the weld metal, it is preferable that P is 0.03% or less and S is 0.03% or less.
また、フラックス充填率は特に限定しないが、生産性の観点からワイヤ全質量に対して８～２０％とするのが好ましい。 The flux filling rate is not particularly limited, but from the viewpoint of productivity, it is preferable that it be 8 to 20% of the total wire mass.
以下、本発明の効果を実施例により具体的に説明する。 The effects of the present invention will be specifically explained below using examples.
まず、鋼製外皮にＪＩＳ Ｇ３１４１ ＳＰＨＣ（Ｃ：０．０２質量％、Ｓｉ：０．０１質量％、Ｍｎ：０．４０質量％、Ｐ：０．０１２質量％、Ｓ：０．０１０質量％）を使用し、鋼製外皮をＵ字形に成形、フラックス充填率を１０～１５％で充填してＣ字形に成形した後、鋼製外皮の合わせ目を溶接して造菅、伸線し、表１に示す各種成分のフラックス入りワイヤを試作した。なお、試作したワイヤ径は１．４ｍｍとした。 First, JIS G3141 SPHC (C: 0.02 mass%, Si: 0.01 mass%, Mn: 0.40 mass%, P: 0.012 mass%, S: 0.010 mass%) was used for the steel sheath, which was formed into a U-shape and filled with flux at a filling rate of 10 to 15% to form it into a C-shape. The seams of the steel sheath were then welded to form a pipe and drawn to produce prototype flux-cored wires with the various compositions shown in Table 1. The diameter of the prototype wire was 1.4 mm.
表１に示す試作したフラックス入りワイヤを用いて、スパッタ発生量、アーク安定性、ビード外観・形状、Ｘ線透過試験による欠陥の有無及び溶接金属性能の調査を行った。 Using the prototype flux-cored wire shown in Table 1, we investigated the amount of spatter generation, arc stability, bead appearance and shape, the presence or absence of defects by X-ray transmission testing, and weld metal performance.
スパッタの発生量は、銅製の捕集箱を用いて、１分間溶接した際に発生するスパッタの重量を測定することにより、単時間当たりの値（ｇ／ｍｉｎ）を求めた。なお、スパッタの測定は、表２に示す条件Ｎｏ．Ｔ１の溶接条件で５回測定した平均値とし、１．５ｇ／ｍｉｎ以下を良好とした。 The amount of spatter generated was determined as a value per unit time (g/min) by measuring the weight of spatter generated during one minute of welding using a copper collection box. The spatter was measured as the average value of five measurements taken under welding conditions No. T1 shown in Table 2, and a value of 1.5 g/min or less was considered good.
アークの安定性は、スパッタ発生量の測定中に１０秒間電圧変動を５回測定し、その電圧の大きさを介して評価した。評価は１に時系列的な電圧変動のチャートを示すが、平均電圧に対して±１Ｖを閾値としたとき、電圧変動が閾値を超える時間が１０秒間で９０％以下の場合をアーク安定とし、電圧変動が閾値を超える時間が１０秒間で１０％を超える場合はアーク不安定とした。 The arc stability was evaluated based on the magnitude of the voltage measured five times for 10 seconds while measuring the amount of spatter generation. The evaluation is shown in a chart of the voltage fluctuation over time in 1. With a threshold of ±1V from the average voltage, the arc was deemed stable if the time during which the voltage fluctuation exceeded the threshold was 90% or less in 10 seconds, and was deemed unstable if the time during which the voltage fluctuation exceeded the threshold was more than 10% in 10 seconds.
ビード外観・形状のビード形状は、溶接ビード健全部で手直しが必要なアンダーカットやオーバーラップがないものを良好とした。ビード外観は、部分的な波形の乱れがなく均一に揃っているものを良好とした。 Regarding bead appearance and shape, a bead shape was deemed good if there were no undercuts or overlaps that required reworking in the healthy weld bead. A bead's appearance was deemed good if it was uniform and free of any partial wave irregularities.
溶接作業性及び溶接金属性能は、表２に示す条件Ｎｏ．Ｔ２（以下、低入熱という。）及び条件Ｎｏ．Ｔ３（以下、大入熱・高パス間という。）の施工条件で、３５°レ形開先、ルートギャップ７ｍｍの裏当金付きの試験体を用いた多層盛溶接金属試験を行い、溶接時のアーク安定性及びビード外観・形状を調査した。溶接終了後、裏当金を削除してＸ線透過試験を行い溶接欠陥の有無を調べた。また、溶接金属部から引張試験片（ＪＩＳ Ｚ２２０１ Ａ０号）及び衝撃試験片（ＪＩＳ Ｚ２２０２ ４号）を採取して機械的性質を調査した。 Welding workability and weld metal performance were investigated by conducting multi-layer weld metal tests using test pieces with a 35° bevel groove and a 7mm root gap and backing metal under the construction conditions of Condition No. T2 (hereinafter referred to as low heat input) and Condition No. T3 (hereinafter referred to as high heat input/high interpass) shown in Table 2, and investigating the arc stability during welding and the bead appearance and shape. After welding was completed, the backing metal was removed and an X-ray transmission test was conducted to check for the presence or absence of welding defects. In addition, tensile test pieces (JIS Z2201 A0) and impact test pieces (JIS Z2202 4) were taken from the weld metal to investigate the mechanical properties.
強度の評価は、引張強さが４９０～６９０ＭＰａ、靭性の評価は、０℃におけるシャルピー衝撃試験を各５本実施し、吸収エネルギーの平均値が８０Ｊ以上、最低値が６０Ｊ以上を良好とした。それらの結果を表３にまとめて示す。 The strength was evaluated as tensile strength of 490 to 690 MPa, and the toughness was evaluated as Charpy impact tests were performed on five pieces at 0°C. A good rating was given for an average absorbed energy of 80 J or more and a minimum of 60 J or more. The results are summarized in Table 3.
表１及び表３中のワイヤ記号Ｗ１～Ｗ１０が本発明例、ワイヤ記号Ｗ１１～Ｗ２２は比較例である。本発明例であるワイヤ記号Ｗ１～Ｗ１０は、フラックス入りワイヤ中のＣ、Ｓｉ、Ｍｎ、Ｍｏ、Ｃｕ、Ｔｉ、Ｂの含有量が適量で、フラックス中の金属弗化物のＦ換算値の合計、Ｓｉ酸化物のＳｉＯ２換算値の合計、Ｎａ酸化物及びＫ酸化物の１種または２種以上のＮａ２Ｏ換算値とＫ２Ｏ換算値の合計が適量であるので、スパッタ発生量が少なく、低入熱及び大入熱・高パス間温度の溶接条件共に、アークが安定して、ビード外観・形状が良好で、溶接欠陥がなく、溶接金属の引張強さ及び吸収エネルギーの平均値及び最低値ともに良好であった。 In Tables 1 and 3, wire symbols W1 to W10 are examples of the present invention, and wire symbols W11 to W22 are comparative examples. Wires W1 to W10, which are examples of the present invention, have appropriate contents of C, Si, Mn, Mo, Cu, Ti, and B in the flux-cored wire, and appropriate amounts of the total of the metal fluorides in the flux in terms of F, the total of the Si oxides in terms of SiO2 , and the total of the Na2O -converted values and K2O -converted values of one or more of Na oxides and K oxides, so that the amount of spatter generation is small, and under both low heat input and high heat input/high interpass temperature welding conditions, the arc is stable, the bead appearance and shape are good, there are no welding defects, and the tensile strength of the weld metal and the average and minimum absorbed energy are both good.
なお、Ａｌ及びＭｇの一方または両方の合計が適量であるワイヤ記号Ｗ２、Ｗ５、Ｗ６及びＷ９は、低入熱及び大入熱・高パス間温度の溶接条件共に溶接金属の吸収エネルギーの平均値が１００Ｊ以上得られ極めて満足な結果であった。 In addition, wire symbols W2, W5, W6 and W9, which have appropriate amounts of either or both of Al and Mg, achieved an average weld metal absorbed energy of 100 J or more under both low heat input and high heat input/high interpass temperature welding conditions, which was extremely satisfactory.
比較例中ワイヤ記号Ｗ１１は、Ｃが少ないので、大入熱・高パス間温度の溶接条件で溶接金属の引張強さが低かった。また、Ｓｉ酸化物のＳｉＯ２換算値の合計が多いので、低入熱及び大入熱・高パス間温度の溶接条件共にスラグ巻き込みが生じ、溶接金属の吸収エネルギーが低値であった。 In the comparative example, wire symbol W11 had low tensile strength of the weld metal under welding conditions of high heat input and high interpass temperature because of low C. In addition, the total SiO2 equivalent value of silicon oxide was high, so slag inclusion occurred under both low heat input and high heat input and high interpass temperature welding conditions, and the absorbed energy of the weld metal was low.
ワイヤ記号Ｗ１２は、Ｃが多いので、低入熱及び大入熱・高パス間温度の溶接条件共に溶接金属の引張強さが高く、吸収エネルギーが低値であった。また、金属弗化物のＦ換算値の合計が多いので、スパッタ発生量が多く、低入熱及び大入熱・高パス間温度の溶接条件共にアークが強く不安定であった。 Wire symbol W12 has a high C content, so the tensile strength of the weld metal was high and the absorbed energy was low under both low heat input and high heat input/high interpass temperature welding conditions. In addition, the total F-equivalent value of the metal fluorides was high, so there was a large amount of spatter generated, and the arc was strong and unstable under both low heat input and high heat input/high interpass temperature welding conditions.
ワイヤ記号Ｗ１３は、Ｓｉが少ないので、低入熱及び大入熱・高パス間温度の溶接条件共に溶接金属の引張強さ及び吸収エネルギーが低値であった。また、Ｓｉ酸化物のＳｉＯ２換算値の合計が少ないので、低入熱及び大入熱・高パス間温度の溶接条件共に溶接ビードの止端部のなじみが悪くビード外観・形状が不良であった。 Wire symbol W13 had low Si content, so the tensile strength and absorbed energy of the weld metal were low under both low heat input and high heat input/high interpass temperature welding conditions. In addition, the total SiO2 equivalent value of Si oxide was low, so the weld bead toe did not conform well under both low heat input and high heat input/high interpass temperature welding conditions, resulting in poor bead appearance and shape.
ワイヤ記号Ｗ１４は、Ｓｉが多いので、低入熱及び大入熱・高パス間温度の溶接条件共にスラグ巻き込みが生じ、溶接金属の引張強さが高く、吸収エネルギーが低値であった。また、金属弗化物のＦ換算値の合計が少ないので、スパッタ発生量が多く、低入熱及び大入熱・高パス間温度の溶接条件共にアークが不安定であった。 Wire symbol W14 contains a lot of Si, so slag inclusion occurred under both low heat input and high heat input/high interpass temperature welding conditions, the tensile strength of the weld metal was high, and the absorbed energy was low. In addition, the total F-converted value of the metal fluorides was low, so there was a lot of spatter generation, and the arc was unstable under both low heat input and high heat input/high interpass temperature welding conditions.
ワイヤ記号Ｗ１５は、Ｍｎが少ないので、大入熱・高パス間温度の溶接条件の溶接金属の引張強さ及び吸収エネルギーが低値であった。また、Ｎａ酸化物及びＫ酸化物の１種または２種以上のＮａ２Ｏ換算値とＫ２Ｏ換算値の合計が少ないので、スパッタ発生量が多く、低入熱及び大入熱・高パス間温度の溶接条件共にアークが不安定であった。 Wire symbol W15 has a low Mn content, so the tensile strength and absorbed energy of the weld metal were low under welding conditions of high heat input and high interpass temperature. In addition, the total of the Na2O equivalent value and the K2O equivalent value of one or more of Na oxides and K oxides was low, so the amount of spatter was large and the arc was unstable under both welding conditions of low heat input and welding conditions of high heat input and high interpass temperature.
ワイヤ記号Ｗ１６は、Ｍｎが多いので、低入熱の溶接条件で溶接金属の引張強さが高く、吸収エネルギーの最低値が低かった。また、Ｍｎが多いので、低入熱及び大入熱・高パス間温度の溶接条件共にスラグ巻き込みが生じた。 Wire symbol W16 has a high Mn content, so the tensile strength of the weld metal was high under low heat input welding conditions, and the minimum absorbed energy was low. Also, because it has a high Mn content, slag inclusion occurred under both low heat input and high heat input/high interpass temperature welding conditions.
ワイヤ記号Ｗ１７は、Ｍｏが少ないので、大入熱・高パス間温度の溶接条件で溶接金属の引張強さが低かった。また、Ｂが少ないので、大入熱・高パス間温度の溶接条件で溶接金属の吸収エネルギーが低値であった。 Wire symbol W17 has a low Mo content, so the tensile strength of the weld metal was low under welding conditions of high heat input and high interpass temperature. Also, because it has a low B content, the absorbed energy of the weld metal was low under welding conditions of high heat input and high interpass temperature.
ワイヤ記号Ｗ１８は、Ｍｏが多いので、低入熱の溶接条件で溶接金属の引張強さが高く、吸収エネルギーの最低値が低かった。また、Ｂが多いので、低入熱及び大入熱・高パス間温度の溶接条件共に初層に高温割れが生じた。 Wire symbol W18 has a high Mo content, so the tensile strength of the weld metal was high under low heat input welding conditions, and the minimum absorbed energy was low. In addition, because it has a high B content, high-temperature cracks occurred in the first layer under both low heat input and high heat input/high interpass temperature welding conditions.
ワイヤ記号Ｗ１９は、Ｃｕが少ないので、低入熱及び大入熱・高パス間温度の溶接条件共に溶接金属の吸収エネルギーの最低値が低値であった。また、Ｎａ酸化物及びＫ酸化物の１種または２種以上のＮａ２Ｏ換算値とＫ２Ｏ換算値の合計が多いので、スパッタ発生量が多く、低入熱及び大入熱・高パス間温度の溶接条件共にアークが不安定で、スラグ巻き込みが生じた。 Wire symbol W19 had a low Cu content, and therefore the minimum absorbed energy of the weld metal was low under both low heat input and high heat input/high interpass temperature welding conditions. In addition, the total of Na2O equivalent value and K2O equivalent value of one or more of Na oxides and K oxides was high, so the amount of spatter was high, and the arc was unstable under both low heat input and high heat input/high interpass temperature welding conditions, and slag inclusion occurred.
ワイヤ記号Ｗ２０は、Ｃｕが多いので、低入熱及び大入熱・高パス間温度の溶接条件共に初層に高温割れが生じ、溶接金属の吸収エネルギーが低値であった。 Wire symbol W20 contains a large amount of Cu, so hot cracks occurred in the first layer under both low heat input and high heat input/high interpass temperature welding conditions, and the absorbed energy of the weld metal was low.
ワイヤ記号Ｗ２１は、Ｔｉが少ないので、大入熱・高パス間温度の溶接条件でアークが不安定で、溶接金属の吸収エネルギーが低値であった。また、Ａｌ及びＭｇの一方または両方の合計が多いので、スパッタ発生量が多く、ヒュームの発生量も多かった。 Wire symbol W21 has a low Ti content, so the arc was unstable under welding conditions of high heat input and high interpass temperature, and the absorbed energy of the weld metal was low. In addition, because the total amount of Al and/or Mg was high, a large amount of spatter was generated and a large amount of fumes were also generated.
ワイヤ記号Ｗ２２は、Ｔｉが多いので、低入熱及び大入熱・高パス間温度の溶接条件共に溶接金属の吸収エネルギーが低値であった。なお、Ａｌ及びＭｇの合計が少ないので、吸収エネルギーを向上する効果は得られなかった。 Wire symbol W22 has a high Ti content, so the absorbed energy of the weld metal was low under both low heat input and high heat input/high interpass temperature welding conditions. In addition, because the total amount of Al and Mg is low, no effect of improving absorbed energy was obtained.
Claims (2)
ワイヤ全質量に対する質量％で、鋼製外皮とフラックスの合計で、
Ｃ：０．０４～０．１０％、
Ｓｉ：０．４～１．４％、
Ｍｎ：１．７～２．５％未満、
Ｍｏ：０．６～１．０％、
Ｃｕ：０．０５～０．５％、
Ｔｉ：０．１～０．４％、
Ｂ：０．００１５～０．０１０％を含有し、
さらに、ワイヤ全質量に対する質量％で、フラックス中に、
金属弗化物：Ｆ換算値の合計で０．００５～０．１０％、
Ｓｉ酸化物：ＳｉＯ２換算値の合計で０．０１～０．２％、
Ｎａ酸化物及びＫ酸化物の１種または２種以上：Ｎａ２Ｏ換算値とＫ２Ｏ換算値の合計で０．０２～０．１４％を含有し、
残部が鋼製外皮のＦｅ、成分調整のために添加する鉄粉、鉄合金粉のＦｅ分及び不可避不純物からなることを特徴とするガスシールドアーク溶接用フラックス入りワイヤ。 A flux-cored wire for gas shielded arc welding, which is made by filling a steel sheath with flux,
The mass percentage of the total wire mass is the sum of the steel sheath and flux.
C: 0.04-0.10%,
Si: 0.4-1.4%,
Mn: 1.7 to less than 2.5%;
Mo: 0.6-1.0%,
Cu: 0.05-0.5%,
Ti: 0.1 to 0.4%,
B: 0.0015 to 0.010%;
Furthermore, in the flux, the mass percentage relative to the total mass of the wire is:
Metal fluorides: 0.005 to 0.10% in total F conversion value,
Si oxides: 0.01 to 0.2% in total in terms of SiO2 ,
One or more of Na oxide and K oxide: 0.02 to 0.14% in total in terms of Na 2 O and K 2 O;
A flux-cored wire for gas shielded arc welding, the balance of which consists of Fe in a steel sheath, iron powder added for adjusting the composition, Fe in iron alloy powder, and unavoidable impurities.
Ａｌ及びＭｇの一方または両方の合計：０．２５％以下をさらに含有することを特徴とする請求項１に記載のガスシールドアーク溶接用フラックス入りワイヤ。 The mass percentage of the total wire mass is the sum of the steel sheath and flux.
2. The flux-cored wire for gas shielded arc welding according to claim 1, further comprising one or both of Al and Mg: 0.25% or less in total.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016124023A (en) | 2015-01-07 | 2016-07-11 | 日鐵住金溶接工業株式会社 | HIGH-TENSION STEEL Ar-CO2 MIXTURE GAS SHIELD ARC-WELDING FLUX-CORED WIRE |
| JP2017131950A (en) | 2016-01-28 | 2017-08-03 | 日鐵住金溶接工業株式会社 | Flux-cored wire for gas shielded arc welding |
| JP2019104026A (en) | 2017-12-12 | 2019-06-27 | 日本製鉄株式会社 | Flux-cored wire for gas shielded arc welding, and method for producing weld joint |
| JP2019118935A (en) | 2018-01-05 | 2019-07-22 | 日本製鉄株式会社 | Flux-cored wire for gas shield arc welding, and method for production of weld joint |
| WO2020110856A1 (en) | 2018-11-27 | 2020-06-04 | 日本製鉄株式会社 | Flux-cored wire, and welding joint production method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH0788688A (en) * | 1993-09-27 | 1995-04-04 | Nippon Steel Corp | MAG welding flux-cored wire with little welding deformation |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016124023A (en) | 2015-01-07 | 2016-07-11 | 日鐵住金溶接工業株式会社 | HIGH-TENSION STEEL Ar-CO2 MIXTURE GAS SHIELD ARC-WELDING FLUX-CORED WIRE |
| JP2017131950A (en) | 2016-01-28 | 2017-08-03 | 日鐵住金溶接工業株式会社 | Flux-cored wire for gas shielded arc welding |
| JP2019104026A (en) | 2017-12-12 | 2019-06-27 | 日本製鉄株式会社 | Flux-cored wire for gas shielded arc welding, and method for producing weld joint |
| JP2019118935A (en) | 2018-01-05 | 2019-07-22 | 日本製鉄株式会社 | Flux-cored wire for gas shield arc welding, and method for production of weld joint |
| WO2020110856A1 (en) | 2018-11-27 | 2020-06-04 | 日本製鉄株式会社 | Flux-cored wire, and welding joint production method |
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| JP2022148804A (en) | 2022-10-06 |
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