JP7506017B2 - Low hydrogen iron powder covered metal arc welding rod - Google Patents
Low hydrogen iron powder covered metal arc welding rod Download PDFInfo
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- JP7506017B2 JP7506017B2 JP2021061672A JP2021061672A JP7506017B2 JP 7506017 B2 JP7506017 B2 JP 7506017B2 JP 2021061672 A JP2021061672 A JP 2021061672A JP 2021061672 A JP2021061672 A JP 2021061672A JP 7506017 B2 JP7506017 B2 JP 7506017B2
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- 239000002184 metal Substances 0.000 title claims description 202
- 229910052751 metal Inorganic materials 0.000 title claims description 201
- 238000003466 welding Methods 0.000 title claims description 130
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 54
- 239000001257 hydrogen Substances 0.000 title claims description 24
- 229910052739 hydrogen Inorganic materials 0.000 title claims description 24
- 125000004435 hydrogen atom Chemical class [H]* 0.000 title 1
- 239000011248 coating agent Substances 0.000 claims description 91
- 238000000576 coating method Methods 0.000 claims description 46
- 239000000463 material Substances 0.000 claims description 38
- 229910045601 alloy Inorganic materials 0.000 claims description 37
- 239000000956 alloy Substances 0.000 claims description 37
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 32
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 29
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 26
- 229910000831 Steel Inorganic materials 0.000 claims description 21
- 239000010959 steel Substances 0.000 claims description 21
- 229910001512 metal fluoride Inorganic materials 0.000 claims description 20
- 239000000843 powder Substances 0.000 claims description 20
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 15
- 229910000521 B alloy Inorganic materials 0.000 claims description 14
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 12
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 229910052796 boron Inorganic materials 0.000 claims description 11
- 229910052681 coesite Inorganic materials 0.000 claims description 11
- 229910052906 cristobalite Inorganic materials 0.000 claims description 11
- 235000012239 silicon dioxide Nutrition 0.000 claims description 11
- 229910052682 stishovite Inorganic materials 0.000 claims description 11
- 229910052905 tridymite Inorganic materials 0.000 claims description 11
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 9
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 8
- 239000012535 impurity Substances 0.000 claims description 8
- 229910052758 niobium Inorganic materials 0.000 claims description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 6
- 229910052797 bismuth Inorganic materials 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 150000002431 hydrogen Chemical class 0.000 claims 1
- 239000011324 bead Substances 0.000 description 38
- 239000002893 slag Substances 0.000 description 36
- 239000010936 titanium Substances 0.000 description 28
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 25
- 239000011777 magnesium Substances 0.000 description 22
- 230000000694 effects Effects 0.000 description 21
- 239000000395 magnesium oxide Substances 0.000 description 13
- 238000002844 melting Methods 0.000 description 13
- 230000008018 melting Effects 0.000 description 13
- 239000011734 sodium Substances 0.000 description 13
- 238000012360 testing method Methods 0.000 description 13
- 229910052710 silicon Inorganic materials 0.000 description 10
- 239000011575 calcium Substances 0.000 description 9
- 239000010949 copper Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 229910052700 potassium Inorganic materials 0.000 description 8
- 239000000523 sample Substances 0.000 description 8
- 229910052593 corundum Inorganic materials 0.000 description 7
- 230000007547 defect Effects 0.000 description 7
- 229910001845 yogo sapphire Inorganic materials 0.000 description 7
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 6
- 229910052748 manganese Inorganic materials 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- 230000000087 stabilizing effect Effects 0.000 description 6
- 239000011573 trace mineral Substances 0.000 description 6
- 235000013619 trace mineral Nutrition 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 5
- 235000019353 potassium silicate Nutrition 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 5
- 238000004090 dissolution Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000009863 impact test Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 4
- 238000009864 tensile test Methods 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 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 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 238000005538 encapsulation Methods 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 239000004111 Potassium silicate Substances 0.000 description 2
- 229910006639 Si—Mn Inorganic materials 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- 238000001636 atomic emission spectroscopy Methods 0.000 description 2
- AOWKSNWVBZGMTJ-UHFFFAOYSA-N calcium titanate Chemical compound [Ca+2].[O-][Ti]([O-])=O AOWKSNWVBZGMTJ-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 2
- 229910052913 potassium silicate Inorganic materials 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000011775 sodium fluoride Substances 0.000 description 2
- 235000013024 sodium fluoride Nutrition 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010456 wollastonite Substances 0.000 description 2
- 229910052882 wollastonite Inorganic materials 0.000 description 2
- 229910052845 zircon Inorganic materials 0.000 description 2
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 2
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 description 1
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 1
- 229910018134 Al-Mg Inorganic materials 0.000 description 1
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 1
- 229910018467 Al—Mg Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910002551 Fe-Mn Inorganic materials 0.000 description 1
- 229910017082 Fe-Si Inorganic materials 0.000 description 1
- 229910002593 Fe-Ti Inorganic materials 0.000 description 1
- 229910017116 Fe—Mo Inorganic materials 0.000 description 1
- 229910017133 Fe—Si Inorganic materials 0.000 description 1
- 101000993059 Homo sapiens Hereditary hemochromatosis protein Proteins 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 239000010436 fluorite Substances 0.000 description 1
- -1 for example Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- KWLMIXQRALPRBC-UHFFFAOYSA-L hectorite Chemical compound [Li+].[OH-].[OH-].[Na+].[Mg+2].O1[Si]2([O-])O[Si]1([O-])O[Si]([O-])(O1)O[Si]1([O-])O2 KWLMIXQRALPRBC-UHFFFAOYSA-L 0.000 description 1
- 229910000271 hectorite Inorganic materials 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000007500 overflow downdraw method Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000012488 sample solution Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 235000010413 sodium alginate Nutrition 0.000 description 1
- 229940005550 sodium alginate Drugs 0.000 description 1
- 239000000661 sodium alginate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- BSVBQGMMJUBVOD-UHFFFAOYSA-N trisodium borate Chemical compound [Na+].[Na+].[Na+].[O-]B([O-])[O-] BSVBQGMMJUBVOD-UHFFFAOYSA-N 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Nonmetallic Welding Materials (AREA)
Description
本発明は、鉄粉低水素系被覆アーク溶接棒に関する。 The present invention relates to an iron powder low hydrogen type covered metal arc welding electrode.
低水素系被覆アーク溶接棒は、アーク安定性が良好で、耐割れ性や溶接金属の低温靱性が優れていることから、拘束が強い箇所や高張力鋼の溶接に広く使用されている。
一方、最近の溶接構造物の大型化にともない、使用鋼材の高強度化が要望されている。 また、天然資源の開発を目的とした大型海洋構造物や球形タンク等では、安全性の確保のため、溶接金属の低温での靱性の更なる向上や、溶接後熱処理（溶接熱影響部の軟化、溶接部の靱性改善及び溶接残留応力の除去を目的に行われる熱処理：以下、ＰＷＨＴという。）後の機械的性能確保が重要となる。しかし、一般に溶接金属の強度増加と低温靱性確保は相反する傾向を示すため、高強度化とともに低温靱性を向上させるためには新たな手法が必要となる。
Low-hydrogen covered electrodes have good arc stability and excellent crack resistance and low-temperature toughness of the weld metal, and are therefore widely used in areas with strong restraint and for welding high-tensile steel.
On the other hand, with the recent increase in the size of welded structures, there is a demand for higher strength steel materials. In addition, in large marine structures and spherical tanks aimed at the development of natural resources, in order to ensure safety, it is important to further improve the toughness of weld metal at low temperatures and ensure mechanical performance after post-weld heat treatment (heat treatment performed for the purpose of softening the weld heat affected zone, improving the toughness of the weld and removing welding residual stress: hereinafter referred to as PWHT). However, since increasing the strength of weld metal and ensuring low-temperature toughness generally show contradictory trends, a new method is required to improve low-temperature toughness while increasing strength.
また、低水素系被覆アーク溶接棒は、一般的に交流電源を用いて溶接するように設計されるが、球形タンクや海洋構造物の現場溶接では直流電源を使用することが多い。低水素系被覆アーク溶接棒を、直流電源を用いて溶接すると、磁気吹きや被覆剤の片溶けが生じてアークが不安定となり、健全なビードが得られないという課題がある。このため、直流電源を使用した場合においても、アークの安定性に優れ、溶接金属の機械性能が良好な鉄粉低水素系被覆アーク溶接棒の開発要望が高い。 Although low-hydrogen covered metal arc welding rods are generally designed to be welded using an AC power source, DC power sources are often used for on-site welding of spherical tanks and marine structures. When low-hydrogen covered metal arc welding rods are welded using a DC power source, problems arise in that magnetic blow and one-sided melting of the coating material occur, making the arc unstable and making it difficult to obtain a sound bead. For this reason, there is a high demand for the development of iron powder low-hydrogen covered metal arc welding rods that have excellent arc stability and good mechanical performance of the weld metal even when using a DC power source.
このような状況に対し、溶接金属の機械的性能の向上手段として、種々提案がされている。例えば、特許文献１には、Ｎｉ含有量が１質量％以下でも低温靱性が優れた溶接金属を得ることを目的とした被覆アーク溶接棒が開示されている。
また、特許文献２には、直流電源を用いた溶接でアーク安定性が良好で低温靱性が優れた溶接金属を得る被覆アーク溶接棒の技術が開示されている。
また、特許文献３には、直流電源を用いた溶接でＣＴＯＤ値（き裂先端開口変位）が優れた溶接金属を得る被覆アーク溶接棒の技術が開示されている。
さらに、特許文献４には、直流電源を用いた溶接でアーク安定性が良好で、ＡＷ（溶接のまま）とＰＷＨＴ後において低温靭性が優れた溶接金属が得られる低水素系被覆アーク溶接棒が開示されている。
In response to this situation, various proposals have been made to improve the mechanical properties of the weld metal. For example, Patent Document 1 discloses a covered metal arc welding rod that aims to obtain a weld metal with excellent low-temperature toughness even when the Ni content is 1 mass % or less.
Furthermore, Patent Document 2 discloses a technique for a covered electrode for producing a weld metal having good arc stability and excellent low-temperature toughness in welding using a DC power source.
Furthermore, Patent Document 3 discloses a technique for a covered metal arc welding electrode that produces a weld metal having an excellent CTOD value (crack tip opening displacement) when welding using a DC power source.
Furthermore, Patent Document 4 discloses a low-hydrogen covered metal arc welding electrode that has good arc stability when used for welding with a DC power source and can provide a weld metal with excellent low-temperature toughness both in AW (as welded) and after PWHT.
特許文献１に記載された被覆アーク溶接棒は、直流電源を用いて溶接を行った場合、磁気吹きや被覆の片溶けが発生しやすいなど十分な溶接作業性が得られない。
特許文献２に記載された被覆アーク溶接棒は、溶接のまま（ＡＷ）では溶接金属の低温靭性の向上は得られるものの、ＰＷＨＴ後の溶接金属では十分な低温靭性が得られない。
特許文献３に記載の技術もＡＷでの溶接金属の機械性能は得られるが、ＰＷＨＴ後では溶接金属の十分な強度及び低温靭性は得られない。
特許文献４に記載された被覆アーク溶接棒は、Ｎｉ含有量が４～８％と非常に多く、高温割れが発生しやすい。
When the covered metal arc welding electrode described in Patent Document 1 is used for welding using a DC power source, magnetic arc blow and one-sided melting of the coating are likely to occur, and sufficient welding workability cannot be obtained.
The covered metal arc welding electrode described in Patent Document 2 improves the low-temperature toughness of the weld metal in the as-welded state (AW), but does not provide sufficient low-temperature toughness in the weld metal after PWHT.
The technique described in Patent Document 3 also provides mechanical properties of the weld metal in AW, but does not provide sufficient strength and low-temperature toughness of the weld metal after PWHT.
The covered metal arc welding electrode described in Patent Document 4 has a very high Ni content of 4 to 8%, and is prone to hot cracking.
本開示は、アーク安定性等の溶接作業性が良好であり、特にＰＷＨＴ後の溶接金属において適正な強度及び低温での優れた靱性が得られる鉄粉低水素系被覆アーク溶接棒を提供することを課題とする。 The objective of this disclosure is to provide an iron powder, low-hydrogen, covered metal arc welding rod that has good welding workability, such as arc stability, and that provides appropriate strength and excellent toughness at low temperatures in the weld metal after PWHT in particular.
前記課題を解決するための本開示の要旨は、以下の通りである。
＜１＞ 鋼心線と、前記鋼心線を被覆する被覆剤とを含み、
溶接棒全質量に対する前記被覆剤の質量割合が２５％以上４０％以下であり、
前記被覆剤が、被覆剤全質量に対する質量％で、
金属又は合金としてのＭｎ：２．０～５．０％、
金属又は合金としてのＮｉ：１．０～２．０％、
金属又は合金としてのＭｏ：０．３～１．５％、
金属又は合金としてのＳｉ：１．５～３．５％
Ｓｉ酸化物のＳｉＯ２換算値：４．０～８．０％
金属炭酸塩の合計：２５～４５％、
金属弗化物の合計：５～１５％、
Ｔｉ酸化物のＴｉＯ２換算値の合計：２．０～７．０％、
Ａｌ酸化物のＡｌ２Ｏ３換算値の合計：０．５～２．５％、
Ｍｇ酸化物のＭｇＯ換算値の合計：０．１～１．０％、
Ｃａ酸化物のＣａＯ換算値の合計：０．３０％以下、
Ｚｒ酸化物のＺｒＯ２換算値の合計：０．５～１．５％、
Ｎａ換算値とＫ換算値の合計：０．５～３．０％、
鉄粉及び鉄合金粉のＦｅ：２０～３５％、並びに
残部：前記Ｍｎから前記Ｆｅまでの成分を除く塗装剤の残部及び１．００％以下の不純物、
を含む鉄粉低水素系被覆アーク溶接棒。
＜２＞ 前記被覆剤が、前記被覆剤を構成する成分の一部に替えて、前記被覆剤全質量に対する質量％で、
金属又は合金としてのＴｉ：３．５０％以下、並びに
金属Ｂ、Ｂ合金、及びＢ酸化物の各Ｂ２Ｏ３換算値の合計：０．６０％以下、
を含む＜１＞に記載の鉄粉低水素系被覆アーク溶接棒。
＜３＞ 前記被覆剤が、前記被覆剤を構成する成分の一部に替えて、前記被覆剤全質量に対する質量％で、
金属又は合金としてのＭｇ：３．０％以下、及び
金属又は合金としてのＡｌ：３．５％以下、
の一方又は両方を含む＜１＞又は＜２＞に記載の鉄粉低水素系被覆アーク溶接棒。
＜４＞ 前記被覆剤が、前記被覆剤を構成する成分の一部に替えて、前記金属炭酸塩及び前記金属弗化物を除く成分として、前記被覆剤全質量に対する質量％で、下記（１）～（５）からなる群より選ばれる一種又は二種以上を含む＜１＞～＜３＞のいずれか１つに記載の鉄粉低水素系被覆アーク溶接棒。
（１）Ｌｉ：０．５％以下
（２）Ｖ、Ｎｂ、及びＴａ：一種又は二種以上の合計で０．５％以下
（３）Ｃｏ：０．５％以下
（４）Ｃｕ及びＢｉ：一種又は二種の合計で０．５％以下
（５）Ｃｒ：０．５％以下
The gist of the present disclosure for solving the above problems is as follows.
<1> A steel core wire and a coating material that coats the steel core wire,
The mass ratio of the coating material to the total mass of the welding rod is 25% or more and 40% or less,
The coating agent is, in mass % based on the total mass of the coating agent,
Mn as metal or alloy: 2.0 to 5.0%;
Ni as metal or alloy: 1.0 to 2.0%,
Mo as metal or alloy: 0.3 to 1.5%,
Si as metal or alloy: 1.5 to 3.5%
Si oxide converted into SiO2 : 4.0 to 8.0%
Total metal carbonates: 25-45%,
Total metal fluorides: 5-15%,
Total of Ti oxides converted into TiO2 : 2.0 to 7.0%,
Sum of Al oxides converted into Al 2 O 3 : 0.5 to 2.5%,
Total Mg oxide converted into MgO: 0.1 to 1.0%,
Sum of Ca oxides converted into CaO: 0.30% or less,
Total Zr oxide converted into ZrO2 : 0.5 to 1.5%,
Sum of Na equivalent and K equivalent: 0.5 to 3.0%,
Fe in the iron powder and iron alloy powder: 20 to 35%, and the balance: the balance of the coating agent excluding the components from Mn to Fe, and impurities of 1.00% or less.
A low hydrogen-based iron powder covered metal arc welding electrode comprising:
<2> The coating agent is, in mass% relative to the total mass of the coating agent, replacing a part of the components constituting the coating agent,
Ti as a metal or alloy: 3.50% or less; and The sum of the B2O3 converted values of metal B, B alloy, and B oxide: 0.60% or less.
The iron powder low hydrogen type covered metal arc welding rod according to <1>,
<3> The coating agent is, in mass% with respect to the total mass of the coating agent, replacing a part of the components constituting the coating agent,
Mg as a metal or alloy: 3.0% or less; and Al as a metal or alloy: 3.5% or less;
The low hydrogen-based iron powder covered metal arc welding rod according to <1> or <2>, comprising one or both of the following:
<4> The iron powder low hydrogen type covered metal arc welding electrode according to any one of <1> to <3>, wherein the coating agent contains, as a component other than the metal carbonate and the metal fluoride, one or more selected from the group consisting of the following (1) to (5), in mass % with respect to the total mass of the coating agent, instead of a part of the components constituting the coating agent:
(1) Li: 0.5% or less (2) V, Nb, and Ta: 0.5% or less in total of one or more of them (3) Co: 0.5% or less (4) Cu and Bi: 0.5% or less in total of one or more of them (5) Cr: 0.5% or less
本開示によれば、アーク安定性等の溶接作業性が良好であり、特にＰＷＨＴ後の溶接金属において適正な強度及び低温での優れた靱性が得られる鉄粉低水素系被覆アーク溶接棒が提供される。 The present disclosure provides an iron powder low-hydrogen covered metal arc welding rod that has good welding workability, such as arc stability, and that provides appropriate strength and excellent toughness at low temperatures in the weld metal after PWHT in particular.
以下、本開示の一例である実施形態について説明する。
なお、本明細書中において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値に「超」又は「未満」が付されていない場合は、これらの数値を下限値及び上限値として含む範囲を意味する。また、「～」の前後に記載される数値に「超」又は「未満」が付されている場合の数値範囲は、これらの数値を下限値又は上限値として含まない範囲を意味する。
本明細書中に段階的に記載されている数値範囲において、ある段階的な数値範囲の上限値は、他の段階的な記載の数値範囲の上限値に置き換えてもよく、実施例に示されている値に置き換えてもよい。また、ある段階的な数値範囲の下限値は、他の段階的な記載の数値範囲の下限値に置き換えてもよく、実施例に示されている値に置き換えてもよい。
含有量について、「％」は特に断りのない限り「質量％」を意味する。
また、含有量（％）について下限値を限定せずに「～％以下」として上限値のみを限定している場合は、０％超～上限値の範囲内で含み得ることを意味する。
Hereinafter, an embodiment that is an example of the present disclosure will be described.
In this specification, when a numerical range expressed using "to" is not preceded or followed by "more than" or "less than", it means a range that includes these numerical values as the lower and upper limits. When "to" is preceded or followed by "more than" or "less than", it means a range that does not include these numerical values as the lower or upper limit.
In the present specification, the upper limit of a certain numerical range may be replaced by the upper limit of another numerical range, or may be replaced by a value shown in an example. The lower limit of a certain numerical range may be replaced by the lower limit of another numerical range, or may be replaced by a value shown in an example.
With respect to the content, "%" means "mass %" unless otherwise specified.
In addition, when the content (%) is specified with only an upper limit such as "not more than ..." without specifying a lower limit, this means that the content may be in the range from more than 0% to the upper limit.
本発明者らは、鉄粉低水素系被覆アーク溶接棒の溶着金属のＰＷＨＴ後の強度及び低温靱性の改善について鋭意研究した結果、被覆剤におけるＭｎ、Ｎｉ及びＭｏの含有量を適正とすることによってＰＷＨＴ後の溶接金属の強度を改善できることを見出し、さらに、金属炭酸塩、Ｓｉ含有量を適正にし、鋼心線への被覆率を適正にすることで、ＰＷＨＴ後の溶接金属の低温靭性を改善できることを見出し、さらに検討を重ねて本発明を完成した。具体的には、鉄粉低水素系被覆アーク溶接棒の被覆剤の被覆率及び被覆剤の成分と効果に関して以下のような知見を得た。 As a result of extensive research into improving the strength and low-temperature toughness of the weld metal after PWHT of low-hydrogen iron powder covered metal arc welding electrodes, the inventors discovered that the strength of the weld metal after PWHT can be improved by optimizing the contents of Mn, Ni, and Mo in the coating, and further discovered that the low-temperature toughness of the weld metal after PWHT can be improved by optimizing the metal carbonate and Si contents and the coating rate on the steel core wire. After further investigation, the inventors completed the present invention. Specifically, the following findings were obtained regarding the coating rate of low-hydrogen iron powder covered metal arc welding electrodes and the components and effects of the coating.
溶接作業性に関しては、アークの安定化及びスパッタ発生量の低減には、被覆率、Ｓｉ、金属炭酸塩、金属弗化物、Ｔｉ酸化物のＴｉＯ２換算値の合計、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計、Ｃａ酸化物のＣａＯ換算値の合計、Ｎａ換算値とＫ換算値の合計、鉄及び鉄合金粉のＦｅを適正にすることで良好になることを見出した。
また、ビード形状及びビード外観は、Ｓｉ酸化物のＳｉＯ２換算値、金属炭酸塩、金属弗化物、Ｔｉ酸化物のＴｉＯ２換算値の合計、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計、Ｍｇ酸化物のＭｇＯ換算値の合計、Ｚｒ酸化物のＺｒＯ２換算値の合計を適正にすることで良好になることを突き止めた。
Regarding welding workability, it was found that the arc can be stabilized and the amount of spatter generated can be reduced by optimizing the coverage, Si, metal carbonates, metal fluorides, the sum of the TiO2 converted values of Ti oxides, the sum of the Al2O3 converted values of Al oxides, the sum of the CaO converted values of Ca oxides, the sum of the Na converted values and the K converted values, and the Fe in the iron and iron alloy powder.
In addition, the inventors have found that the bead shape and bead appearance can be improved by optimizing the amounts of Si oxide in terms of SiO2 , metal carbonates, metal fluorides, the sum of Ti oxide in terms of TiO2 , the sum of Al oxide in terms of Al2O3 , the sum of Mg oxide in terms of MgO, and the sum of Zr oxide in terms of ZrO2 .
さらに、スラグ剥離性は、Ｓｉ酸化物のＳｉＯ２換算値、金属炭酸塩、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計を適正にすることで良好になることを見出した。
また、溶接棒自体が赤熱する棒焼けを防止するには、鉄及び鉄合金粉のＦｅを適正にすることで、溶接棒の保護筒の片溶けを防止するには金属弗化物、Ｍｇ酸化物のＭｇＯ換算値の合計、Ｚｒ酸化物のＺｒＯ２換算値の合計、鉄及び鉄合金粉のＦｅを適正にすることで、被覆剤の塗装性等の溶接棒の生産性はＮａ換算値とＫ換算値の合計を適正にすることで良好になることを見出した。
Furthermore, it was found that the slag removability can be improved by optimizing the total of the SiO2 equivalent value of silicon oxide, the metal carbonate, and the Al2O3 equivalent value of aluminum oxide.
In addition, it was found that in order to prevent rod burn, in which the welding rod itself becomes red hot, the Fe content of the iron and iron alloy powder should be adjusted appropriately, and in order to prevent one-sided melting of the protective tube of the welding rod, the total of the metal fluoride, the Mg oxide's MgO equivalent value, the total of the Zr oxide's ZrO2 equivalent value, and the Fe content of the iron and iron alloy powder should be adjusted appropriately, and that the productivity of the welding rod, such as the paintability of the coating agent, can be improved by adjusting the total of the Na equivalent value and the K equivalent value.
さらに、Ｔｉと金属Ｂ及びＢ合金並びにＢ酸化物の合計、Ｍｇ及びＡｌの一種或いは両方の適量により低温での溶接金属の靭性がさらに向上することを見出した。
また、Ｌｉ、Ｖ、Ｃｒ、Ｃｏ、Ｃｕ、Ｎｂ、Ｔａ、Ｂｉを適量含有することで様々な効果が得られることを見出した。
Furthermore, it has been found that the toughness of the weld metal at low temperatures can be further improved by adding an appropriate amount of the total of Ti and metal B, B alloy and B oxide, and one or both of Mg and Al.
In addition, it was found that various effects can be obtained by containing appropriate amounts of Li, V, Cr, Co, Cu, Nb, Ta, and Bi.
＜鉄粉低水素系被覆アーク溶接棒＞
本開示に係る鉄粉低水素系被覆アーク溶接棒（本開示において「被覆アーク溶接棒」又は単に「溶接棒」などと称する場合がある。）は、鋼心線と、鋼心線を被覆する被覆剤とを含んで構成されている。
<Iron powder low hydrogen type covered metal arc welding electrode>
The iron powder low hydrogen type covered metal arc welding rod according to the present disclosure (which may be referred to as a “covered metal arc welding rod” or simply a “welding rod” in the present disclosure) includes a steel core wire and a coating material that coats the steel core wire.
（鋼心線）
鋼心線は、公知の低水素系被覆アーク溶接棒に使用される鋼心線を用いることができる。例えば、ＪＩＳ Ｇ ３５２３：１９８０に規定されるＳＷＹ１１の線材から製造した心線を用いることが好ましい。
(Steel core wire)
The steel core wire may be a steel core wire used in a known low-hydrogen covered metal arc welding rod. For example, it is preferable to use a core wire manufactured from SWY11 wire material specified in JIS G 3523:1980.
（被覆剤）
鋼心線の外周面には、被覆剤全質量に対する質量％で、
金属又は合金としてのＭｎ：２．０～５．０％、
金属又は合金としてのＮｉ：１．０～２．０％、
金属又は合金としてのＭｏ：０．３～１．５％、
金属又は合金としてのＳｉ：１．５～３．５％
Ｓｉ酸化物のＳｉＯ２換算値：４．０～８．０％、
金属炭酸塩の合計：２５～４５％、
金属弗化物の合計：５～１５％、
Ｔｉ酸化物のＴｉＯ２換算値の合計：２．０～７．０％、
Ａｌ酸化物のＡｌ２Ｏ３換算値の合計：０．５～２．５％、
Ｍｇ酸化物のＭｇＯ換算値の合計：０．１～１．０％、
Ｃａ酸化物のＣａＯ換算値の合計：０．３０％以下
Ｚｒ酸化物のＺｒＯ２換算値の合計：０．５～１．５％、
Ｎａ換算値とＫ換算値の合計：０．５～３．０％、並びに
鉄粉及び鉄合金粉のＦｅ：２０～３５％、
を含有し、さらに前記Ｍｎから前記Ｆｅまでの成分を除く塗装剤の残部と１．００％以下の不純物を含む被覆剤が塗装されている。
(Coating agent)
The outer surface of the steel core wire is coated with the following material (mass % relative to the total mass of the coating material):
Mn as metal or alloy: 2.0 to 5.0%;
Ni as metal or alloy: 1.0 to 2.0%,
Mo as metal or alloy: 0.3 to 1.5%,
Si as metal or alloy: 1.5 to 3.5%
Si oxide converted into SiO2 : 4.0 to 8.0%,
Total metal carbonates: 25-45%,
Total metal fluorides: 5-15%,
Total of Ti oxides converted into TiO2 : 2.0 to 7.0%,
Sum of Al oxides converted into Al 2 O 3 : 0.5 to 2.5%,
Total Mg oxide converted into MgO: 0.1 to 1.0%,
Sum of Ca oxides converted into CaO: 0.30% or less Sum of Zr oxides converted into ZrO2 : 0.5 to 1.5%,
The sum of Na and K converted values: 0.5 to 3.0%, and Fe in iron powder and iron alloy powder: 20 to 35%,
and further comprising the remainder of the coating agent excluding the components from Mn to Fe, and a coating agent containing 1.00% or less of impurities.
以下、本開示に係る鉄粉低水素系被覆アーク溶接棒の被覆剤の成分組成及び成分組成の限定理由について詳細に説明する。なお、各成分の含有量は、被覆剤全質量に対する質量％で表すこととし、その質量％を表すときには単に％と記載することとする。また、本開示に係る溶接棒の被覆剤を構成する成分に関し、例えば、「金属炭酸塩の合計」とは、金属炭酸塩を一種のみ含んでもよいし、二種以上含んでもよく、二種以上含む場合はそれらの合計含有量を意味する。「金属弗化物の合計」についても同様である。
また、酸化物に関し、例えば「Ｔｉ酸化物のＴｉＯ２換算値」とは、ＴｉＯ２以外のＴｉ酸化物も含め、Ｔｉ酸化物として含まれるＴｉが全てＴｉＯ２として含まれているとみなして換算した値を意味する。
The composition of the coating material of the iron powder low hydrogen type covered metal arc welding electrode according to the present disclosure and the reasons for limiting the composition of the components will be described in detail below. The content of each component is expressed as mass% relative to the total mass of the coating material, and when expressing the mass%, it will be written simply as %. In addition, with regard to the components constituting the coating material of the welding electrode according to the present disclosure, for example, "total of metal carbonates" may contain only one type of metal carbonate or may contain two or more types, and when two or more types are contained, it means the total content of them. The same applies to "total of metal fluorides".
Regarding oxides, for example, " TiO2 equivalent value of Ti oxide" means a value calculated by assuming that all Ti contained as Ti oxide is contained as TiO2 , including Ti oxides other than TiO2 .
また、後述する「金属Ｂ、Ｂ合金、及びＢ酸化物の各Ｂ２Ｏ３換算値の合計」とは、金属Ｂ、Ｂ合金、及びＢ酸化物のいずれか一種又は二種以上を含んでもよく、また、例えばＢ合金を含む場合は一種又は二種以上のＢ合金を含んでもよいが、Ｂ酸化物だけでなく、金属Ｂ及びＢ合金も「Ｂ２Ｏ３」に換算した含有量とし、「各Ｂ２Ｏ３換算値の合計：０．６０％以下」とは、いずれの場合においてもＢ２Ｏ３換算値の合計が０．６０％以下であることを意味する。 Furthermore, the "total of the B 2 O 3 equivalent values of metal B, B alloy, and B oxide" described below may include any one or more of metal B, B alloy, and B oxide, and may also include, for example, one or more of B alloys when B alloy is included, but it refers to the content converted into "B 2 O 3 " of not only B oxide but also metal B and B alloy, and "the sum of the B 2 O 3 equivalent values: 0.60% or less" means that the sum of the B 2 O 3 equivalent values is 0.60% or less in any case.
［被覆率：溶接棒全質量に対する被覆剤の質量％で２５～４０％］
被覆剤の鋼心線の外周への被覆率は、溶接時の耐シールド性に大きく影響する。被覆率が鉄粉低水素系被覆アーク溶接棒全質量に対する被覆剤の質量％（以下、単に％という。）で２５％未満では、被覆剤自体が少なくなってシールド不足となり、溶接金属中のＮ含有量が増加してＰＷＨＴ後の溶接金属の靱性が低下する。一方、被覆剤の被覆率が４０％を超えると、スラグ量が過多となってアークが不安定になる。従って、被覆率は２５～４０％とする。
なお、溶接棒全質量に対する被覆剤の質量割合（被覆率：％）は、以下の式によって算出される値である。
被覆率％＝被覆剤質量／溶接棒全質量×１００
[Covering rate: 25-40% by mass of coating material relative to the total mass of the welding rod]
The coverage rate of the coating material on the outer circumference of the steel core wire has a large effect on the shielding resistance during welding. If the coverage rate is less than 25% by mass of the coating material relative to the total mass of the iron powder low hydrogen type covered metal arc welding electrode (hereinafter simply referred to as %), the coating material itself becomes less, resulting in insufficient shielding, and the N content in the weld metal increases, reducing the toughness of the weld metal after PWHT. On the other hand, if the coverage rate of the coating material exceeds 40%, the amount of slag becomes excessive and the arc becomes unstable. Therefore, the coverage rate is set to 25 to 40%.
The mass ratio of the coating material to the total mass of the welding rod (coverage rate: %) is a value calculated by the following formula.
Coverage % = mass of coating material / total mass of welding rod × 100
［金属又は合金としてのＭｎ：２．０～５．０％］
Ｍｎは、金属又は合金、例えば金属Ｍｎ、Ｆｅ－Ｍｎ、Ｆｅ－Ｓｉ－Ｍｎ等として含有され、Ｓｉと同様に脱酸剤として重要であり、溶接金属組織を微細化して溶接金属の低温靱性及び強度を高める効果がある。また、焼入れ性が強いことから、ＰＷＨＴ後の溶接金属の強度確保にも有効である。Ｍｎが２．０％未満では、ＰＷＨＴ後の溶接金属の強度及び低温靭性が低下する。また、脱酸不足となって溶接金属中にブローホールが発生しやすくなる。一方、Ｍｎが５．０％を超えると、溶接金属の強度が過剰に高くなり、靭性が低下する。また、焼入れ性が強く作用し、ＰＷＨＴ後の溶接金属の強度が高くなって靱性が低下する。従って、Ｍｎは２．０～５．０％とする。
[Mn as metal or alloy: 2.0 to 5.0%]
Mn is contained as a metal or an alloy, such as metal Mn, Fe-Mn, Fe-Si-Mn, etc., and is important as a deoxidizer like Si, and has the effect of refining the weld metal structure and increasing the low-temperature toughness and strength of the weld metal. In addition, since it has strong hardenability, it is also effective in ensuring the strength of the weld metal after PWHT. If the Mn content is less than 2.0%, the strength and low-temperature toughness of the weld metal after PWHT will decrease. In addition, deoxidization will be insufficient, and blowholes will easily occur in the weld metal. On the other hand, if the Mn content exceeds 5.0%, the strength of the weld metal will be excessively high and the toughness will decrease. In addition, the hardenability will be strong, and the strength of the weld metal after PWHT will be high and the toughness will decrease. Therefore, the Mn content is set to 2.0 to 5.0%.
［金属又は合金としてのＮｉ：１．０～２．０％］
Ｎｉは、金属又は合金、例えば金属ＮｉやＮｉ合金粉等として含有され、ＰＷＨＴ後の溶接金属の強度及び低温靭性を向上させる効果がある。Ｎｉが１．０％未満では、ＰＷＨＴ後の溶接金属の強度及び低温靭性が低下する。一方、Ｎｉが２．０％を超えると、溶接金属の強度が過剰に高くなる。従って、Ｎｉは１．０～２．０％とする。
[Ni as metal or alloy: 1.0 to 2.0%]
Ni is contained as a metal or alloy, for example, Ni metal or Ni alloy powder, and has the effect of improving the strength and low-temperature toughness of the weld metal after PWHT. If Ni is less than 1.0%, the strength and low-temperature toughness of the weld metal after PWHT decrease. On the other hand, if Ni exceeds 2.0%, the strength of the weld metal becomes excessively high. Therefore, Ni is set to 1.0 to 2.0%.
［金属又は合金としてのＭｏ：０．３～１．５％］
Ｍｏは、金属又は合金、例えば金属Ｍｏ、Ｆｅ－Ｍｏ等として含有され、溶接金属の強度をより向上させる効果がある。また、焼入れ性が強いことから、ＰＷＨＴ後の強度確保にも有効である。Ｍｏが０．３％未満では、ＰＷＨＴ後の溶接金属の強度が低下する。一方、Ｍｏが１．５％を超えると、ＰＷＨＴ後の溶接金属の強度が過剰に高くなり、靭性が低下する。従って、Ｍｏは０．３～１．５％とする。
[Mo as metal or alloy: 0.3 to 1.5%]
Mo is contained as a metal or alloy, such as metallic Mo, Fe-Mo, etc., and has the effect of further improving the strength of the weld metal. In addition, since it has strong hardenability, it is also effective in ensuring strength after PWHT. If Mo is less than 0.3%, the strength of the weld metal after PWHT decreases. On the other hand, if Mo exceeds 1.5%, the strength of the weld metal after PWHT becomes excessively high and the toughness decreases. Therefore, Mo is set to 0.3 to 1.5%.
［金属又は合金としてのＳｉ：１．５～３．５％］
Ｓｉは、金属又は合金、例えば金属Ｓｉ、Ｆｅ－Ｓｉ、Ｆｅ－Ｓｉ－Ｍｎ等として含有され、溶接金属の脱酸を目的として使用される。Ｓｉが１．５％未満では、脱酸不足となって溶接金属中にブローホールが発生しやすくなり、アークも不安定となる。一方、Ｓｉが３．５％を超えると、溶接金属の粒界に低融点酸化物を析出させ、溶接金属の低温靱性が低下する。従って、Ｓｉは１．５～３．５％とする。
[Si as metal or alloy: 1.5 to 3.5%]
Silicon is contained as a metal or an alloy, such as metal silicon, Fe-Si, Fe-Si-Mn, etc., and is used for the purpose of deoxidizing the weld metal. If the silicon content is less than 1.5%, deoxidation is insufficient, making blowholes more likely to occur in the weld metal and making the arc unstable. On the other hand, if the silicon content exceeds 3.5%, low-melting-point oxides are precipitated at the grain boundaries of the weld metal, reducing the low-temperature toughness of the weld metal. Therefore, the silicon content is set to 1.5 to 3.5%.
［Ｓｉ酸化物のＳｉＯ２換算値：４．０～８．０％］
Ｓｉ酸化物のＳｉＯ２換算値は、珪砂、ジルコンサンド、カリ長石、珪酸ナトリウムや珪酸カリウム等の水ガラスの固質分、珪灰石等として含有され、溶融スラグの粘性を高め、適切な粘性のスラグを確保してビード形状を良好にする効果がある。Ｓｉ酸化物のＳｉＯ２換算値が４．０％未満では、溶融スラグの粘性が低くなり、ビード形状が不良となる。一方、Ｓｉ酸化物のＳｉＯ２換算値が８．０％を超えると、スラグがガラス状になり、スラグ剥離性が不良になる。従って、Ｓｉ酸化物のＳｉＯ２換算値は４．０～８．０％とする。
[ SiO2 equivalent value of Si oxide: 4.0 to 8.0%]
The SiO2 equivalent of Si oxide is contained as silica sand, zircon sand, potassium feldspar, solid components of water glass such as sodium silicate and potassium silicate, wollastonite, etc., and has the effect of increasing the viscosity of the molten slag, ensuring slag with appropriate viscosity, and improving the bead shape. If the SiO2 equivalent of Si oxide is less than 4.0%, the viscosity of the molten slag will be low and the bead shape will be poor. On the other hand, if the SiO2 equivalent of Si oxide exceeds 8.0%, the slag will become glassy and the slag removability will be poor. Therefore, the SiO2 equivalent of Si oxide is set to 4.0 to 8.0%.
［金属炭酸塩の合計：２５～４５％］
金属炭酸塩は、炭酸カルシウム、炭酸マグネシウム、炭酸バリウム等として含有され、アークの熱で分解してＣＯ２ガスを発生し、溶接金属を大気から保護する効果がある。金属炭酸塩の一種又は二種以上の合計が２５％未満では、シールド効果が不足し、ブローホールが発生しやすくなる。また、溶接金属中に大気中の窒素が混入し、ＰＷＨＴ後の低温靱性が低下する。一方、金属炭酸塩の一種又は二種以上の合計が４５％を超えると、アークが不安定となってビード形状が凸状になり、スラグ剥離性も悪くなる。従って、金属炭酸塩の合計は２５～４５％とする。
[Total of metal carbonates: 25-45%]
Metal carbonates are contained as calcium carbonate, magnesium carbonate, barium carbonate, etc., and decompose with the heat of the arc to generate CO2 gas, which has the effect of protecting the weld metal from the atmosphere. If the total of one or more metal carbonates is less than 25%, the shielding effect is insufficient and blowholes are likely to occur. In addition, nitrogen from the atmosphere is mixed into the weld metal, reducing the low-temperature toughness after PWHT. On the other hand, if the total of one or more metal carbonates exceeds 45%, the arc becomes unstable, the bead shape becomes convex, and slag removability is also poor. Therefore, the total of the metal carbonates is set to 25-45%.
［金属弗化物の合計：５～１５％］
金属弗化物は、蛍石、弗化マグネシウム、弗化アルミニウム、弗化リチウム、弗化ナトリウム、珪弗化カリウム等として含有され、溶融スラグの流動性を調整してビード外観を良好にする効果がある。金属弗化物の一種又は二種以上の合計が５％未満では、溶融スラグの流動性が悪くなりスラグ被包性が悪くなってビード外観が不良になる。一方、金属弗化物の一種又は二種以上の合計が１５％を超えると、被覆筒の形状が不完全となって片溶け状態となり、アークが不安定となる。従って、金属弗化物の合計は５～１５％とする。
[Total of metal fluorides: 5-15%]
Metal fluorides are contained as fluorite, magnesium fluoride, aluminum fluoride, lithium fluoride, sodium fluoride, potassium silicofluoride, etc., and have the effect of adjusting the fluidity of the molten slag and improving the bead appearance. If the total of one or more metal fluorides is less than 5%, the fluidity of the molten slag is poor, the slag encapsulation is poor, and the bead appearance is poor. On the other hand, if the total of one or more metal fluorides exceeds 15%, the shape of the covering tube becomes incomplete, resulting in a one-sided melting state and an unstable arc. Therefore, the total of the metal fluorides is set to 5-15%.
［Ｔｉ酸化物のＴｉＯ２換算値の合計：２．０～７．０％］
Ｔｉ酸化物は、ルチール、酸化チタン、チタンスラグ、チタン酸カルシウム等として含有され、アークを安定にし、溶融スラグの粘性を調整してビード形状を良好にする効果がある。Ｔｉ酸化物のＴｉＯ２換算値の合計が２．０％未満であると、アークが不安定となり、ビード形状が不良になる。一方、Ｔｉ酸化物のＴｉＯ２換算値の合計が７．０％を超えると、溶融スラグの粘性が高くなってスラグの流動性が悪くなるので、ビード形状が凸状となる。従って、Ｔｉ酸化物のＴｉＯ２換算値の合計は２．０～７．０％とする。
[Total of Ti oxides converted into TiO2 : 2.0 to 7.0%]
Ti oxides are contained as rutile, titanium oxide, titanium slag, calcium titanate, etc., and have the effect of stabilizing the arc and adjusting the viscosity of the molten slag to improve the bead shape. If the total of the Ti oxides in terms of TiO2 is less than 2.0%, the arc becomes unstable and the bead shape becomes poor. On the other hand, if the total of the Ti oxides in terms of TiO2 exceeds 7.0%, the viscosity of the molten slag increases and the fluidity of the slag deteriorates, resulting in a convex bead shape. Therefore, the total of the Ti oxides in terms of TiO2 is set to 2.0 to 7.0%.
［Ａｌ酸化物のＡｌ２Ｏ３換算値の合計：０．５～２．５％］
Ａｌ酸化物は、アルミナ、カリ長石等として含有され、アークを安定させるとともにビード形状を良好にする効果がある。Ａｌ酸化物のＡｌ２Ｏ３の合計が０．５％未満であると、アークが不安定となりビード形状が不良となる。一方、Ａｌ酸化物のＡｌ２Ｏ３の合計が２．５％を超えると、スラグがガラス状となってスラグ剥離性が不良になる。従って、Ａｌ酸化物のＡｌ２Ｏ３の合計は０．５～２．５％とする。
[Total Al2O3 converted value of Al oxide : 0.5 to 2.5%]
Aluminum oxide is contained as alumina, potassium feldspar, etc., and has the effect of stabilizing the arc and improving the bead shape. If the total amount of aluminum oxide (Al 2 O 3 ) is less than 0.5%, the arc becomes unstable and the bead shape becomes poor. On the other hand, if the total amount of aluminum oxide (Al 2 O 3 ) exceeds 2.5%, the slag becomes glassy and the slag removability becomes poor. Therefore, the total amount of aluminum oxide (Al 2 O 3 ) is set to 0.5-2.5%.
［Ｍｇ酸化物のＭｇＯ換算値の合計：０．１～１．０％］
Ｍｇ酸化物は、酸化マグネシウム、マグネシアクリンカー等として含有され、耐熱性に優れており、被覆剤の片溶けを抑制する効果がある。Ｍｇ酸化物のＭｇＯ換算値の合計が０．１％未満では、被覆剤の片溶けが発生しやすくなる。一方、Ｍｇ酸化物のＭｇＯ換算値の合計が１．０％を超えると、溶融スラグの粘性が高くなるので、ビード形状が凸状となる。従って、Ｍｇ酸化物のＭｇＯ換算値の合計は０．１～１．０％とする。
[Total of Mg oxides converted into MgO: 0.1 to 1.0%]
Mg oxide is contained as magnesium oxide, magnesia clinker, etc., has excellent heat resistance, and is effective in suppressing one-sided dissolution of the coating agent. If the total of Mg oxides in terms of MgO is less than 0.1%, one-sided dissolution of the coating agent is likely to occur. On the other hand, if the total of Mg oxides in terms of MgO exceeds 1.0%, the viscosity of the molten slag increases, and the bead shape becomes convex. Therefore, the total of Mg oxides in terms of MgO is set to 0.1 to 1.0%.
［Ｃａ酸化物のＣａＯ換算値の合計：０．３０％以下］
Ｃａ酸化物は、チタン酸カルシウム、珪灰石等として含有され、アークを安定化させてスパッタ発生の低減に効果がある。Ｃａ酸化物のＣａＯ換算値の合計が０．３０％を超えると、アークが弱くなって不安定になり、融合不良等の溶接欠陥が発生しやすくなる。従って、Ｃａ酸化物のＣａＯ換算値の合計は０．３０％以下とする。
[Total of Ca oxides converted into CaO: 0.30% or less]
Ca oxides are contained as calcium titanate, wollastonite, etc., and are effective in stabilizing the arc and reducing the occurrence of spatter. If the total of Ca oxides converted into CaO exceeds 0.30%, the arc becomes weak and unstable, and welding defects such as poor fusion are likely to occur. Therefore, the total of Ca oxides converted into CaO is set to 0.30% or less.
［Ｚｒ酸化物のＺｒＯ２換算値の合計：０．５～１．５％］
Ｚｒ酸化物は、ジルコンサンド、ジルコニア等として含有され、融点が２７００℃と高く、被覆剤及び鋼心線が過熱した際も安定した耐火性を有し、被覆剤の片溶けを抑制する上で有効である。Ｚｒ酸化物のＺｒＯ２換算値の合計が０．５％未満では、被覆剤の片溶けが発生しやすくなる。一方、Ｚｒ酸化物のＺｒＯ２換算値の合計が１．５％を超えると、溶融スラグの粘性が高くなってスラグの流動性が悪くなり、ビード形状が凸状となる。従って、Ｚｒ酸化物のＺｒＯ２換算値の合計は０．５～１．５％とする。
[Total of Zr oxide converted into ZrO2 : 0.5 to 1.5%]
Zr oxide is contained as zircon sand, zirconia, etc., and has a high melting point of 2700°C, and has stable fire resistance even when the coating material and steel core wire are overheated, and is effective in suppressing one-sided melting of the coating material. If the total of Zr oxides converted into ZrO2 is less than 0.5%, one-sided melting of the coating material is likely to occur. On the other hand, if the total of Zr oxides converted into ZrO2 exceeds 1.5%, the viscosity of the molten slag increases, the fluidity of the slag deteriorates, and the bead shape becomes convex. Therefore, the total of Zr oxides converted into ZrO2 is set to 0.5 to 1.5%.
［Ｎａ換算値とＫ換算値の合計：０．５～３．０％］
Ｎａは、珪酸ナトリウム等の水ガラスの固質分や弗化ナトリウム等として含有され、また、Ｋは、珪酸カリウム等の水ガラスの固質分、珪弗化カリウム及びカリ長石等として含有され、溶接棒製造時の塗装性及び溶接時のアークの安定性を向上する効果がある。Ｎａ換算値とＫ換算値の合計が０．５％未満では、アークが不安定になる。また、生産時の塗装性が悪くなるとともに、溶接棒製造時に被覆剤表面に割れが生じやすくなるなど被覆アーク溶接棒の生産性が低下する。一方、Ｎａ換算値とＫ換算値の合計が３．０％を超えると、アークの吹き付けが強くなり、スパッタ発生量が多くなる。従って、Ｎａ換算値とＫ換算値の合計は０．５～３．０％とする。なお、ＮａとＫの含有形態は限定されず、金属、合金、他の化合物として含まれていてもよい。また、ＮａとＫを両方含んでもよいし、ＮａとＫの一方は含まない、すなわち０％であってもよい。
[Total of Na and K converted values: 0.5 to 3.0%]
Na is contained as a solid component of water glass such as sodium silicate or sodium fluoride, and K is contained as a solid component of water glass such as potassium silicate, potassium silicofluoride, and potassium feldspar, and has the effect of improving the paintability during the manufacture of the welding rod and the stability of the arc during welding. If the total of the Na equivalent value and the K equivalent value is less than 0.5%, the arc becomes unstable. In addition, the paintability during production deteriorates, and cracks are likely to occur on the coating surface during the manufacture of the welding rod, so that the productivity of the covered arc welding rod decreases. On the other hand, if the total of the Na equivalent value and the K equivalent value exceeds 3.0%, the arc blow becomes strong and the amount of spatter generation increases. Therefore, the total of the Na equivalent value and the K equivalent value is set to 0.5 to 3.0%. The form of inclusion of Na and K is not limited, and they may be contained as metals, alloys, or other compounds. In addition, both Na and K may be contained, or one of Na and K may not be contained, that is, 0%.
［鉄粉及び鉄合金粉のＦｅ：２０～３５％］
鉄粉及び鉄合金粉のＦｅ（鉄粉及び鉄合金粉として含まれるＦｅ）は、アークの電位傾度を低下させてアーク長を短くして被覆剤の片溶けを防止させる効果があり、特に直流電源を用いた溶接において最も重要な原材料である。鉄粉及び鉄合金粉のＦｅが２０％未満では、アーク長が長くなって被覆剤の片溶けが発生しやすくなる。一方、鉄粉及び鉄合金粉のＦｅが３５％を超えると、被覆アーク溶接棒による溶接では溶接後半になると被覆アーク溶接棒自体が赤熱（以下、棒焼けという。）してしまい、溶接が困難となる。従って、鉄粉及び鉄合金粉のＦｅは２０～３５％とする。
[Fe in iron powder and iron alloy powder: 20 to 35%]
The Fe in the iron powder and iron alloy powder (Fe contained in the iron powder and iron alloy powder) has the effect of reducing the potential gradient of the arc, shortening the arc length, and preventing one-sided melting of the coating material, and is the most important raw material, especially in welding using a DC power source. If the Fe content of the iron powder and iron alloy powder is less than 20%, the arc length becomes long and one-sided melting of the coating material is likely to occur. On the other hand, if the Fe content of the iron powder and iron alloy powder exceeds 35%, in welding with a covered electrode, the covered electrode itself becomes red hot (hereinafter referred to as "rod burn") in the latter half of welding, making welding difficult. Therefore, the Fe content of the iron powder and iron alloy powder is set to 20-35%.
本開示に係る被覆アーク溶接棒の被覆剤は、上記各成分の一部に替えて、以下の成分を含んでもよい。 The coating material of the covered metal arc welding electrode according to the present disclosure may contain the following components instead of some of the above components.
［金属又は合金としてのＴｉ：３．５％以下］
Ｔｉは、金属又は合金、例えば金属Ｔｉ、Ｆｅ－Ｔｉ等として含有され、脱酸剤として有効であると同時に、アークの電位傾度を低下させてアークを安定化させる効果がある。Ｔｉが３．５％を超えると、溶接金属中のＴｉ酸化物の析出が増加し、溶接金属の低温靱性が低下する。従って、Ｔｉは３．５％以下とする。
[Ti as metal or alloy: 3.5% or less]
Ti is contained as a metal or alloy, for example, metallic Ti, Fe-Ti, etc., and is effective as a deoxidizer, and at the same time, has the effect of lowering the potential gradient of the arc and stabilizing the arc. If Ti exceeds 3.5%, the precipitation of Ti oxide in the weld metal increases, and the low-temperature toughness of the weld metal decreases. Therefore, Ti is set to 3.5% or less.
［金属Ｂ、Ｂ合金、及びＢ酸化物の各Ｂ２Ｏ３換算値の合計：０．６％以下］
金属Ｂ、Ｂ合金、及びＢ酸化物はＦｅ－Ｂ、Ｆｅ－Ｍｎ－Ｂ、三酸化硼素、硼酸ナトリウム等として含有され、微量で焼入れ性を向上させて粒界フェライトの生成抑制に有効な元素で、溶接金属の低温靭性の向上に効果がある。金属Ｂ、Ｂ合金、及びＢ酸化物の一種又は二種以上のＢ２Ｏ３換算値の合計が０．６％を超えると、溶接金属が粗大なラス状組織になり、溶接金属の低温靭性が低下する。従って、金属Ｂ、Ｂ合金及びＢ酸化物の各Ｂ２Ｏ３換算値の合計は０．６％以下とする。
[Total of B2O3 converted values of metal B, B alloy, and B oxide: 0.6 % or less]
Metal B, B alloy, and B oxide are contained as Fe-B, Fe-Mn-B, boron trioxide, sodium borate, etc., and are effective elements in improving hardenability and suppressing the formation of grain boundary ferrite in small amounts, and are effective in improving the low-temperature toughness of the weld metal. If the total of the B2O3 -equivalent values of one or more of metal B, B alloy, and B oxide exceeds 0.6%, the weld metal will become a coarse lath-like structure, and the low-temperature toughness of the weld metal will decrease. Therefore, the total of the B2O3 - equivalent values of metal B, B alloy, and B oxide should be 0.6% or less.
［金属又は合金としてのＭｇ：３．０％以下］
Ｍｇは、金属又は合金、例えば金属Ｍｇ、Ａｌ－Ｍｇ等として含有され、脱酸剤として有効であり、溶接金属の低温靭性を向上させる。また、アークの電位傾度を低下させてアークを安定化させる効果がある。Ｍｇが３．０％を超えると、溶接金属中のＳｉやＭｎ等、その他脱酸剤が溶接金属中に残存し、溶接金属のミクロ組織が得られないため、溶接金属の低温靭性を劣化させる。従って、Ｍｇは３．０％以下とする。
[Mg as metal or alloy: 3.0% or less]
Mg is contained as a metal or alloy, for example, metallic Mg, Al-Mg, etc., and is effective as a deoxidizer, improving the low-temperature toughness of the weld metal. It also has the effect of lowering the potential gradient of the arc and stabilizing the arc. If Mg exceeds 3.0%, other deoxidizers such as Si and Mn in the weld metal remain in the weld metal, and the microstructure of the weld metal cannot be obtained, deteriorating the low-temperature toughness of the weld metal. Therefore, Mg is set to 3.0% or less.
［金属又は合金としてのＡｌ：３．５％以下］
Ａｌは、金属又は合金、例えば金属Ａｌ、Ｆｅ－Ａｌ等として含有され、脱酸剤として有効であり、溶接金属の低温靭性を向上させる。Ａｌが３．５％を超えると、溶接金属中のＳｉやＭｎ等、その他脱酸剤が溶接金属中に残存し、溶接金属のミクロ組織が得られないため、溶接金属の低温靭性を劣化させる。従って、Ａｌは３．５％以下とする。
[Al as metal or alloy: 3.5% or less]
Al is contained as a metal or alloy, for example, metallic Al, Fe-Al, etc., and is effective as a deoxidizer, improving the low-temperature toughness of the weld metal. If Al exceeds 3.5%, other deoxidizers in the weld metal, such as Si and Mn, remain in the weld metal, and the microstructure of the weld metal cannot be obtained, deteriorating the low-temperature toughness of the weld metal. Therefore, Al is set to 3.5% or less.
［Ｌｉ、Ｖ、Ｃｒ、Ｃｏ、Ｃｕ、Ｎｂ、Ｔａ、Ｂｉ］
Ｌｉ、Ｖ、Ｃｒ、Ｃｏ、Ｃｕ、Ｎｂ、Ｔａ、Ｂｉ（本開示において「微量元素」と記す場合がある。）は、溶接金属に微量含有することで、様々な効果を得られる。
Ｌｉ：アークを安定にする効果が得られるが、０．５％を超えるとアークが強くなり、スパッタが多くなる。
Ｖ、Ｎｂ、Ｔａ：アークの吹き付け強さを強くするが、一種又は二種以上の合計で０．５％を超えると溶接金属の強度が高くなる。
Ｃｏ：アークの集中性が良くなるが、０．５％を超えると強度が高くなる
Ｃｕ、Ｂｉ：スラグ剥離性が良くなるが、一種又は二種の合計で０．５％を超えると高温割れが生じやすくなる。
Ｃｒ：溶接ビードの防錆効果があるが、０．５％を超えると溶接金属の強度が高くなる。
以上から、被覆剤は、下記（１）～（５）からなる群より選ばれる一種又は二種以上を含んでもよい。
（１）Ｌｉ：０．５％以下
（２）Ｖ、Ｎｂ、及びＴａ：一種又は二種以上の合計で０．５％以下
（３）Ｃｏ：０．５％以下
（４）Ｃｕ及びＢｉ：一種又は二種の合計で０．５％以下
（５）Ｃｒ：０．５％以下
なお、これらの微量元素は、（１）～（５）の群のうち２つ以上の群を含んでもよい。例えば、（１）０．５％以下のＬｉと（５）０．５％以下のＣｒを含んでもよい。
また、被覆剤がこれらの微量元素を含む場合、各微量元素は前述の金属炭酸塩及び金属弗化物を除く成分として含まれる。すなわち、これらの微量元素は、金属又は合金として含まれていてもよいし、合金、金属炭酸塩、及び金属弗化物以外の化合物として含まれていてもよい。例えば、被覆剤が、前述した金属弗化物として弗化リチウムを含む場合、弗化リチウム以外に０．５％以下のＬｉを含んでもよい。
[Li, V, Cr, Co, Cu, Nb, Ta, Bi]
Various effects can be obtained by including trace amounts of Li, V, Cr, Co, Cu, Nb, Ta, and Bi (which may be referred to as "trace elements" in this disclosure) in the weld metal.
Li: Has the effect of stabilizing the arc, but if it exceeds 0.5%, the arc becomes stronger and more spatter occurs.
V, Nb, Ta: These elements increase the arc blow strength, but if the total content of one or more elements exceeds 0.5%, the strength of the weld metal increases.
Co: Improves arc concentration, but if it exceeds 0.5%, strength increases. Cu, Bi: Improves slag removability, but if the total content of one or both exceeds 0.5%, hot cracking becomes more likely to occur.
Cr: Has an anti-rust effect on the weld bead, but if it exceeds 0.5%, the strength of the weld metal increases.
In view of the above, the coating agent may contain one or more types selected from the group consisting of the following (1) to (5).
(1) Li: 0.5% or less (2) V, Nb, and Ta: 0.5% or less in total of one or more of them (3) Co: 0.5% or less (4) Cu and Bi: 0.5% or less in total of one or more of them (5) Cr: 0.5% or less These trace elements may include two or more of the groups (1) to (5). For example, it may include (1) 0.5% or less Li and (5) 0.5% or less Cr.
In addition, when the coating agent contains these trace elements, each trace element is contained as a component other than the above-mentioned metal carbonate and metal fluoride. That is, these trace elements may be contained as metals or alloys, or may be contained as compounds other than alloys, metal carbonates, and metal fluorides. For example, when the coating agent contains lithium fluoride as the above-mentioned metal fluoride, it may contain 0.5% or less of Li in addition to lithium fluoride.
［その他］
本開示に係る溶接棒の被覆剤は、上記の成分以外の残部として、上記成分を除く塗装剤の残部及び不純物を含む。
塗装剤は生産性の観点から含有されており、例えばアルギン酸ソーダ、ヘクトライトなどが挙げられる。被覆剤における塗装剤の含有量は、例えば５．０％以下である。なお、塗装剤の残部とは、塗装剤のうち前述した成分以外の成分であり、例えば有機物が挙げられる。
不純物は、原材料に含まれる成分や、製造の過程で混入される成分であって、被覆剤に意図的に含有させた成分ではない成分である。被覆剤に含まれる不純物としては、有機物、合金粉に含まれるＰやＳなどが挙げられる。不純物の総量は望ましくは１．００％以下である。
[others]
The coating material for the welding rod according to the present disclosure contains, as the balance other than the above-mentioned components, the balance of the coating material excluding the above-mentioned components and impurities.
The coating agent is included from the viewpoint of productivity, and examples of the coating agent include sodium alginate and hectorite. The content of the coating agent in the covering agent is, for example, 5.0% or less. The remainder of the coating agent is the components of the coating agent other than the above-mentioned components, and examples of the coating agent include organic substances.
Impurities are components contained in raw materials or components mixed in during the manufacturing process, but are not intentionally contained in the coating agent. Impurities contained in the coating agent include organic matter, and P and S contained in alloy powder. The total amount of impurities is preferably 1.00% or less.
なお、本開示における被覆剤の組成成分はＪＩＳ Ｋ１１０６：２０１４に記載のＩＣＰ発光分光分析方法を用いて調査した。試料は試作溶接棒の被覆剤を剥がして回収し、粉砕した粉末試料とした。粉末試料の分解には、酸分解法又はアルカリ融解法を用いた。溶液の一部を噴霧してＩＣＰ発光分光分析装置のアルゴンプラズマ中に導入し、定量成分の分析線の発光強度又は定量成分の分析線の発光強度の内標準元素の発光強度に対する比を測定した。得られた発光強度から検量線法を用いて試料溶液中の測定対象元素の濃度を求めた。
また、ＳｉとＳｉＯ２など、金属系と酸化物系の定量分析にはＸ線回折分析法を用いた。例えば被覆剤中のＳｉ量を、ＩＣＰ発光分光分析方法を用いて特定し、同じ被覆剤を用いてＸ線回折分析法で金属系Ｓｉと酸化物系Ｓｉを測定し、それぞれの定量分析値を求めた。なお、分析精度を高めるために、被覆剤はメノウ乳鉢などで１０μｍ以下の細粒に粉砕することが望ましい。試料充填の手順は、１０ｃｍ角、厚さ５ｍｍ程度の厚みのある平らなガラス板の上にガラス試料板を置き、深さ０．５ｍｍ程度の溝にガラス板で抑え、試料板の表面と試料面が同一面になるように仕上げてＸ線回折分析装置で分析を行った。
The composition of the coating agent in this disclosure was investigated using the ICP optical emission spectrometry method described in JIS K1106:2014. The coating agent of the prototype welding rod was peeled off, collected, and pulverized to obtain a powder sample. The powder sample was decomposed using an acid decomposition method or an alkali fusion method. A part of the solution was sprayed and introduced into the argon plasma of an ICP optical emission spectrometry analyzer, and the emission intensity of the analytical line of the quantitative component or the ratio of the emission intensity of the analytical line of the quantitative component to the emission intensity of the internal standard element was measured. The concentration of the element to be measured in the sample solution was determined from the obtained emission intensity using a calibration curve method.
In addition, X-ray diffraction analysis was used for quantitative analysis of metals and oxides such as Si and SiO2 . For example, the amount of Si in the coating agent was specified using ICP emission spectroscopy, and the metal Si and oxide Si were measured using the same coating agent by X-ray diffraction analysis to obtain the quantitative analysis values of each. In order to improve the analytical accuracy, it is desirable to crush the coating agent into fine particles of 10 μm or less using an agate mortar. The procedure for filling the sample was to place a glass sample plate on a flat glass plate with a size of 10 cm square and a thickness of about 5 mm, hold it down with a glass plate in a groove with a depth of about 0.5 mm, finish it so that the surface of the sample plate and the sample surface are on the same plane, and analyze it with an X-ray diffraction analysis device.
また、使用する鋼心線は、ＪＩＳ Ｇ３５２３：１９８０ ＳＷＹ１１を用いることが好ましいが、Ｃは０．０８％以下が良く、溶接金属の強度を調整するために被覆剤からもＣを適正に調整できる。鋼心線のＰは溶接金属の靭性を低下させるので０．０１０％以下、Ｓは溶接時のスラグの流動性を悪くするので０．０１０％以下であることが好ましい。 The steel core wire used should preferably be JIS G3523:1980 SWY11, with C being 0.08% or less, and C can be adjusted appropriately from the coating material to adjust the strength of the weld metal. P in the steel core wire reduces the toughness of the weld metal, so it is preferable that it be 0.010% or less, and S reduces the fluidity of the slag during welding, so it is preferable that it be 0.010% or less.
［溶着金属］
本開示に係る溶接棒を用いて形成される溶着金属は、溶接後熱処理（溶接熱影響部の軟化、溶接部の靱性改善及び溶接残留応力の除去を目的に行われる熱処理：以下、ＰＷＨＴという。）後の引張強さが５９０～７２０ＭＰａであり、かつＡＷＳ Ａ５．５：２０１４に規定されるシャルピー衝撃試験の－５０℃でのシャルピー吸収エネルギーが４０Ｊ以上であることが好ましい。
[Weld metal]
It is preferable that the weld metal formed using the welding rod according to the present disclosure has a tensile strength of 590 to 720 MPa after post-weld heat treatment (heat treatment performed for the purpose of softening the weld heat affected zone, improving the toughness of the weld, and removing welding residual stress: hereinafter referred to as PWHT) and a Charpy absorbed energy of 40 J or more at −50° C. in the Charpy impact test specified in AWS A5.5:2014.
（引張強さ）
本開示に係る溶接棒を用いて作製した溶着金属試験体に対するＰＷＨＴは、温度６２０℃、保持時間１．０ｈｒの条件で行った。本開示に係る溶接棒を用いれば、溶着金属のＰＷＨＴ後の引張強さを５９０～７２０ＭＰａの範囲とすることができる。
溶着金属の引張強さが５９０ＭＰａ以上であることで、高い継手強度を確保することができる。一方、溶着金属の引張強さが７２０ＭＰａ以下であることで溶着金属の割れ発生を抑制できる。溶着金属の引張強さはＡＷＳ Ａ５．５：２０１４に準拠し、引張試験片（ＡＷＳ Ｂ４．０：２００７）を用いた引張試験により測定される。試料片の採取位置など、具体的な測定方法については実施例において説明する。
(Tensile strength)
The PWHT of the weld metal specimen prepared using the welding rod according to the present disclosure was performed at a temperature of 620° C. and a holding time of 1.0 hr. By using the welding rod according to the present disclosure, the tensile strength of the weld metal after the PWHT can be set in the range of 590 to 720 MPa.
A high joint strength can be ensured by setting the tensile strength of the weld metal to 590 MPa or more. On the other hand, a high tensile strength can be suppressed by setting the tensile strength of the weld metal to 720 MPa or less. The tensile strength of the weld metal is measured by a tensile test using a tensile test piece (AWS B4.0:2007) in accordance with AWS A5.5:2014. Specific measurement methods, such as the sampling position of the sample piece, will be described in the examples.
（低温靭性）
本開示に係る溶接棒を用いて作製した溶着金属試験体は、溶着金属の－５０℃でのシャルピー吸収エネルギーの平均値が４０Ｊ以上であることが好ましい。より好ましくは６０Ｊ以上、さらに好ましくは８０Ｊ以上である。シャルピー衝撃試験はＡＷＳ Ａ５．５：２０１４に準拠し、試験温度－５０℃で５回繰り返し、最高値及び最低値を除いた３つの吸収エネルギーの平均値（算術平均）である。試料片の採取位置など、具体的な測定方法については実施例において説明する。
(Low temperature toughness)
In the weld metal specimens prepared using the welding rod according to the present disclosure, the average Charpy absorbed energy of the weld metal at -50°C is preferably 40 J or more. More preferably, it is 60 J or more, and even more preferably, it is 80 J or more. The Charpy impact test conforms to AWS A5.5:2014, and is repeated five times at a test temperature of -50°C, and the average value (arithmetic mean) of the three absorbed energies excluding the highest and lowest values is obtained. Specific measurement methods, such as the sampling position of the sample pieces, will be described in the examples.
（溶接欠陥）
本開示に係る溶接棒を用いて作製した溶着金属試験体は、ブローホールなどの溶接欠陥が抑制されていることが好ましい。具体的には、ＡＷＳ Ａ５．５に準じてＸ線透過試験を行い、きずが無いことが好ましい。
(Welding defects)
It is preferable that the weld metal test specimens produced using the welding rod according to the present disclosure have suppressed welding defects such as blowholes. Specifically, it is preferable that the weld metal test specimens have no flaws when subjected to an X-ray transmission test in accordance with AWS A5.5.
（スパッタ発生量）
本開示に係る溶接棒は、スパッタ発生量が少ないことが好ましい。
(Amount of spatter generated)
It is preferable that the welding rod according to the present disclosure generates a small amount of spatter.
（アーク安定性）
本開示に係る溶接棒は、アークが安定してアーク切れが発生しないことが好ましい。
(Arc stability)
In the welding rod according to the present disclosure, it is preferable that the arc is stable and no arc interruption occurs.
（ビード形状・ビード外観）
本開示に係る溶接棒を用いて作製した溶着金属試験体は、溶着金属のビード波形が、均一で乱れが無く、手直しが必要なアンダーカットおよびオーバーラップが発生しないことが好ましい。
(Bead shape and appearance)
It is preferable that a weld metal test specimen prepared using a welding rod according to the present disclosure has a uniform and undisturbed bead waveform of the weld metal, and is free of undercuts and overlaps that require rework.
（スラグ剥離性）
本開示に係る溶接棒は、溶接後、溶接ビード表面上の凝固スラグを簡単に除去できることが好ましい。
(Slag removability)
The welding rod according to the present disclosure preferably allows easy removal of solidified slag on the surface of the weld bead after welding.
（被覆剤の片溶け）
本開示に係る溶接棒は、溶接中に被覆剤の一部が欠けることなくアークが溶接棒と水平に発生し、アーク拡がりが均一で安定していることが好ましい。
(Partial dissolution of coating material)
In the welding rod according to the present disclosure, it is preferable that an arc is generated horizontally to the welding rod without any chipping of the coating material during welding, and that the arc spread is uniform and stable.
（棒焼け）
本開示に係る溶接棒は、溶接時に赤熱して溶接中に被覆剤が脱落することが無いことが好ましい。
(stick burn)
It is preferable that the welding rod according to the present disclosure does not become red hot during welding and the coating material does not fall off during welding.
以下、本開示の効果を実施例により更に詳細に説明するが、本開示は以下の実施例に限定されるものではない。 The effects of this disclosure will be explained in more detail below using examples, but this disclosure is not limited to the following examples.
＜被覆アーク溶接棒の製造＞
直径４．０ｍｍ、長さ４００ｍｍのＪＩＳ Ｇ ３５２３：２００６に規定されるＳＷＹ１１の鋼心線（鋼心線全質量に対し、Ｃ：０．０６質量％、Ｓｉ：０．０１質量％、Ｍｎ：０．４８質量％、Ｐ：０．００９質量％、Ｓ：０．００５質量％）に、表１及び表２に示す組成成分の被覆剤を溶接棒全質量に対して被覆率２５～４０質量％で塗布した後に４００℃で焼成した溶接棒を各種試作した。なお、表１及び表２の被覆剤成分について「－」との表記はその成分を意図的に含有させていないことを意味する。残部は、塗装剤の残部、合金粉から不純物で、１．００％以下に調整した。下線は、本開示の範囲外であることを示す。
<Manufacture of covered electrodes>
Various prototypes of welding rods were produced by applying a coating agent having the composition shown in Tables 1 and 2 to a steel core wire of SWY11 specified in JIS G 3523:2006 (C: 0.06 mass%, Si: 0.01 mass%, Mn: 0.48 mass%, P: 0.009 mass%, S: 0.005 mass% relative to the total mass of the steel core wire) having a diameter of 4.0 mm and a length of 400 mm at a coating rate of 25 to 40 mass% relative to the total mass of the welding rod, and then baking at 400°C. Note that the notation "-" for the coating agent components in Tables 1 and 2 means that the component is not intentionally contained. The balance is the remainder of the coating agent and impurities from the alloy powder, and was adjusted to 1.00% or less. Underlines indicate that the content is outside the scope of the present disclosure.
製造した溶接棒の生産性、溶接作業性、溶接欠陥及び機械的性質について調査した。 The productivity, welding workability, welding defects and mechanical properties of the manufactured welding rods were investigated.
［生産性］
溶接棒製造時に溶接棒を乾燥した後に、被覆剤表面に亀裂が生じる乾燥割れが発生する場合がある。乾燥割れは溶接時に保護筒が均一に形成されなくなり、アークが偏向するなど、溶接作業性に悪影響を及ぼす。生産性は、溶接棒製造時に乾燥後の被覆割れの有無を調べた。個々の乾燥割れの大きさが１ｍｍより小さい場合を合格（良好）、個々の乾燥割れの大きさが１ｍｍ以上を不合格（不良）とした。
[Productivity]
Drying cracks, which are cracks on the coating surface, may occur after the welding rod is dried during manufacturing. Drying cracks cause the protective tube to be formed unevenly during welding, and cause the arc to deflect, adversely affecting welding workability. Productivity was evaluated by checking the presence or absence of coating cracks after drying during manufacturing of the welding rod. If the size of each drying crack was less than 1 mm, it was considered to be acceptable (good), and if the size of each drying crack was 1 mm or more, it was considered to be unacceptable (bad).
＜溶着金属試験体の製造＞
溶着金属試験体は、上記製造した溶接棒を用い、開先部は、表３に示す成分を有するＪＩＳ Ｇ ３１０６：２０１７ ＳＭ４９０Ａの板厚２０ｍｍの鋼板を開先角度：２０°、ギャップ１６ｍｍの裏当金付開先とし、直流電源を用いて溶接電流１７０Ａ、溶接入熱１７ｋＪ／ｃｍ、予熱・パス間温度９５～１１０℃の条件で溶着金属試験体を作製した。ＰＷＨＴは、温度６２０℃、保持時間１．０ｈｒの条件で行った。
<Production of Weld Metal Test Pieces>
The weld metal test specimens were prepared using the welding rods manufactured above, and the grooves were made of JIS G 3106:2017 SM490A steel plates having a thickness of 20 mm and the components shown in Table 3, with a groove angle of 20° and a backing metal groove with a gap of 16 mm. A weld metal test specimen was prepared using a DC power source under the conditions of a welding current of 170 A, a welding heat input of 17 kJ/cm, and a preheat/interpass temperature of 95 to 110° C. The PWHT was performed at a temperature of 620° C. and a holding time of 1.0 hr.
［溶接作業性］
（アーク安定性）
溶接時にアークが安定しており、アークが消失しなかった場合を良好、一度でもアークが消失した場合を不良とした。
[Welding workability]
(Arc stability)
If the arc was stable during welding and did not disappear, it was rated as good, and if the arc disappeared even once, it was rated as poor.
（スパッタ発生量）
溶接時のスパッタ発生量が少ないことが好ましい。具体的には、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４に示す溶接条件で５回測定した平均値とし、２．０ｇ／ｍｉｎ以下を良好とした。
(Amount of spatter generated)
It is preferable that the amount of spatter generated during welding is small. Specifically, the weight of spatter generated during one minute of welding was measured using a copper collection box to determine the value per unit time (g/min). The spatter was measured five times under the welding conditions shown in Table 4, and the average value was determined, with 2.0 g/min or less being considered good.
（ビード形状・ビード外観）
溶着金属のビード波形が均一で乱れが無く、手直しが必要なアンダーカット及びオーバーラップが発生しないことが好ましい。溶着金属の余盛高さ及びビード幅の均一性に優れたビード形状を有することが好ましい。具体的には、溶着金属のビード表面において、ビード波形に乱れがある場合、並びに、手直しが必要なアンダーカット及び／又はオーバーラップが発生した場合のいずれか一方でも該当する場合を不良とした。
(Bead shape and appearance)
It is preferable that the bead waveform of the deposited metal is uniform and free of disturbance, and that undercuts and overlaps that require rework do not occur. It is preferable that the deposited metal has a bead shape with excellent uniformity in the excess height and bead width. Specifically, a case in which either the bead waveform is disturbed on the bead surface of the deposited metal or undercuts and/or overlaps that require rework occur is determined as defective.
（スラグ剥離性）
溶接後、溶接ビード表面上の凝固スラグを簡単に除去できることが好ましい。溶接後、溶接ビード表面上の凝固スラグをチッピングハンマー（全長３００ｍｍ、重さ３５０ｇ）を用いて、持ち手を中心に円弧に軽い力で振り下ろして叩いた時に、スラグに亀裂が入りその後簡単に除去できる場合を良好、スラグに亀裂が入らない場合を不良とした。
(Slag removability)
It is preferable that the solidified slag on the weld bead surface can be easily removed after welding. After welding, the solidified slag on the weld bead surface was struck with a chipping hammer (total length 300 mm, weight 350 g) by swinging it down lightly in an arc around the handle. If the slag cracked and could be easily removed, it was rated as good, and if the slag did not crack, it was rated as poor.
（被覆剤の片溶け）
溶接中に被覆剤の一部が欠けることなくアークが溶接棒と水平に発生し、アーク拡がりが均一で安定していることが好ましい。溶接中に被覆剤の一部が欠け、アークが溶接棒と水平以外の方向に偏向し、アーク拡がりが不均一になる場合を不良とした。
(Partial dissolution of coating material)
It is preferable that the arc is generated parallel to the welding rod without any chipping of the coating material during welding, and that the arc spread is uniform and stable. If part of the coating material is chipped during welding, the arc is deflected in a direction other than parallel to the welding rod, and the arc spread is non-uniform, it is rated as defective.
（棒焼け）
溶接時に赤熱して溶接中に被覆剤が脱落することが無いことが好ましい。溶接時に溶接棒の色が変わらず同じ場合を良好、溶接時に赤熱して溶接棒の色が赤色に変色した場合を不良とした。
(stick burn)
It is preferable that the coating does not fall off during welding because the welding rod becomes red hot. A welding rod that does not change color during welding is rated as good, and a welding rod that becomes red hot and turns red is rated as bad.
［溶接欠陥］
具体的には、ＡＷＳ Ａ５．５に準じてＸ線透過試験を行い、溶接金属におけるきずを判定した。きずが無い場合を良好（欠陥無し）、きずが一つでもある場合を不良とした。
[Welding defects]
Specifically, an X-ray test was performed in accordance with AWS A5.5 to judge whether there were any flaws in the weld metal. A specimen without flaws was rated as good (no defects), and a specimen with even one flaw was rated as poor.
［機械的性質］
機械的性質の評価は、ＪＩＳ Ｇ ３１０６：２０１７ ＳＭ４９０Ａの板厚２０ｍｍの鋼板を用い、ＡＷＳ Ａ５．５に準じてＤＣ（直流電源）で溶着金属試験体を作製し、引張試験（ＡＷＳ Ｂ４．０：２００７）とシャルピー衝撃試験（ＡＷＳ Ｂ４．０：２００７）の各試験片を採取して機械的性能を調査した。
引張試験は引張強さが５９０～７２０ＭＰａを良好とし、シャルピー衝撃試験は試験温度－５０℃で各々繰り返し５回のうち、最低値と最高値を除いた３回の平均値が４０Ｊ以上を良好とした。
[mechanical nature]
For the evaluation of mechanical properties, a 20 mm thick steel plate of JIS G 3106:2017 SM490A was used, and a deposited metal test specimen was prepared using DC (direct current power source) in accordance with AWS A5.5. Test specimens were then taken for a tensile test (AWS B4.0:2007) and a Charpy impact test (AWS B4.0:2007) to investigate the mechanical properties.
In the tensile test, a tensile strength of 590 to 720 MPa was considered good, and in the Charpy impact test, a test temperature of -50°C was repeated five times, and an average of three values excluding the minimum and maximum values of 40 J or more was considered good.
試験結果を表５に示す。 The test results are shown in Table 5.
表１、表２及び表５中の溶接棒Ｎｏ．１～Ｎｏ．１４が本発明例、溶接棒Ｎｏ．１５～Ｎｏ．２８は比較例である。
本発明例であるＮｏ．１～Ｎｏ．１４は、被覆剤のＭｎ、Ｎｉ、Ｍｏ、ＳｉとＳｉ酸化物のＳｉ換算値との合計、金属炭酸塩、金属弗化物、Ｔｉ酸化物のＴｉＯ２換算値の合計、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計、Ｍｇ酸化物のＭｇＯ換算値の合計、Ｃａ酸化物のＣａＯ換算値の合計、Ｚｒ酸化物のＺｒＯ２換算値の合計、Ｎａ換算値とＫ換算値の合計、鉄粉及び鉄合金粉のＦｅ、被覆率がいずれも適量であるので、アーク状態が良好でスパッタ発生量が少なく、保護筒の状態も良好で、棒焼けも発生せず、ビード外観、ビード形状、スラグ剥離性及びスラグ被包性が良好であるなど溶接作業性が良好である。また、生産性も良好であり、溶接欠陥も無く、ＰＷＨＴ後の溶着金属の引張強さ及び吸収エネルギーが良好であり、極めて満足な結果であった。
In Tables 1, 2 and 5, welding rods No. 1 to No. 14 are examples of the present invention, and welding rods No. 15 to No. 28 are comparative examples.
In the present invention, No. 1 to No. 14 have a suitable amount of Mn, Ni, Mo, Si, Si oxides in the coating agent, metal carbonate, metal fluoride, Ti oxides in TiO2 equivalent, Al oxides in Al2O3 equivalent, Mg oxides in MgO equivalent, Ca oxides in CaO equivalent, Zr oxides in ZrO2 equivalent, Na and K equivalent, Fe in iron powder and iron alloy powder, and the coating rate, so that the arc condition is good, the amount of spatter generation is small, the condition of the protective tube is good, rod burn does not occur, the bead appearance, bead shape, slag detachability and slag encapsulation are good, and the welding workability is good. In addition, the productivity is good, there are no welding defects, and the tensile strength and absorbed energy of the weld metal after PWHT are good, which is an extremely satisfactory result.
さらに、Ｎｏ．２、Ｎｏ．１０、Ｎｏ．１１はＴｉ、金属Ｂ、Ｂ合金、及びＢ酸化物のＢ２Ｏ３換算値の合計が適量であり、Ｎｏ．４、Ｎｏ．１２、Ｎｏ．１３はＭｇ、Ａｌが適量であるので、その他の発明例よりも低温靭性が優れていた。
また、Ｎｏ．６はＮｂが適量であるので、その他の発明例よりもアークの吹き付け強さが強かった。Ｎｏ．８はＢｉが適量であるので、その他の発明例よりもスラグ剥離性が良好であった。Ｎｏ．１４はＣｒが適量であるので、その他の発明例よりも溶接ビードの防錆効果があった。
Furthermore, No. 2, No. 10, and No. 11 had appropriate amounts of Ti, metal B, B alloy, and the total of B oxide converted into B2O3 , and No. 4, No. 12, and No. 13 had appropriate amounts of Mg and Al, so they had better low-temperature toughness than the other inventive examples.
In addition, No. 6 had a higher arc blow strength than the other inventive examples because it contained an appropriate amount of Nb. No. 8 had better slag removability than the other inventive examples because it contained an appropriate amount of Bi. No. 14 had a higher rust prevention effect on the weld bead than the other inventive examples because it contained an appropriate amount of Cr.
比較例中、溶接棒Ｎｏ．１５は、被覆率が低く、Ｓｉが少なく、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計が多く、Ｍｇ酸化物のＭｇＯ換算値の合計が少なく、Ｚｒ酸化物のＺｒＯ２換算値の合計が多いので、スラグ剥離性が不良で、ビード形状が凸状となり、アークが不安定で、ブローホールが発生し、片溶けが発生し、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．１６は、被覆率が高く、Ｍｎが多く、Ｓｉ酸化物が多く、Ｚｒ酸化物のＺｒＯ２換算値の合計が少ないので、スラグ剥離性が不良で、アークが不安定で、片溶けが発生し、ＰＷＨＴ後の溶着金属の引張強さが高く、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．１７は、Ｍｎが少なく、金属炭酸塩の合計が多いので、スラグ剥離性が不良で、ビード形状が凸状となり、アークが不安定で、ブローホールが発生し、ＰＷＨＴ後の溶着金属の引張強さが低く、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．１８は、Ｎｉが多く、Ｓｉ酸化物が少なく、Ｃａ酸化物のＣａＯ換算値の合計が多いので、ビード形状が不良で、アークが不安定で、融合不良が発生し、ＰＷＨＴ後の溶着金属の引張強さが高かった。
溶接棒Ｎｏ．１９は、Ｎｉが低く、金属弗化物が多く、Ｍｇ酸化物のＭｇＯ換算値の合計が多いので、ビード形状が凸状で、アークが不安定で、片溶けが発生し、ＰＷＨＴ後の溶着金属の引張強さが低く、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
Among the comparative examples, welding rod No. 15 had a low coverage, a low amount of Si, a high total amount of Al oxide converted into Al2O3 , a low total amount of Mg oxide converted into MgO, and a high total amount of Zr oxide converted into ZrO2 , which resulted in poor slag removability, a convex bead shape, an unstable arc, blowholes, and one-sided melting, and the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 16 had a high coverage, a large amount of Mn, a large amount of Si oxide, and a small total amount of Zr oxide converted into ZrO2 , so that the slag removability was poor, the arc was unstable, one-sided melting occurred, the tensile strength of the weld metal after PWHT was high, and the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 17 had a low Mn content and a high total metal carbonate content, which resulted in poor slag removability, a convex bead shape, an unstable arc, blowholes, low tensile strength of the weld metal after PWHT, and low absorbed energy of the weld metal after PWHT.
Welding rod No. 18 had a large amount of Ni, a small amount of Si oxide, and a large amount of Ca oxide converted into CaO, so the bead shape was poor, the arc was unstable, poor fusion occurred, and the tensile strength of the weld metal after PWHT was high.
Welding rod No. 19 had a low Ni content, a high metal fluoride content, and a high total Mg oxide MgO conversion value, so the bead shape was convex, the arc was unstable, one-sided melting occurred, the tensile strength of the weld metal after PWHT was low, and the absorbed energy of the weld metal after PWHT was low.
溶接棒Ｎｏ．２０は、Ｍｏが多く、Ｔｉ酸化物のＴｉＯ２換算値の合計が多いので、ビード形状が凸状で、ＰＷＨＴ後の溶着金属の引張強さが高く、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２１は、Ｍｏが少なく、Ｔｉ酸化物のＴｉＯ２換算値の合計が少ないので、ビード形状が不良で、アークが不安定で、ＰＷＨＴ後の溶着金属の引張強さが低かった。
溶接棒Ｎｏ．２２は、Ｓｉが多く、Ａｌ酸化物のＡｌ２Ｏ３換算値の合計が少ないので、ビード形状が不良で、アークが不安定で、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２３は、金属炭酸塩が少なく、Ｎａ換算値とＫ換算値の合計が多いので、アークが強く、スパッタが多く、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２４は、Ｎａ換算値とＫ換算値の合計が少なく、鉄粉及び鉄合金粉のＦｅが多いので、アークが不安定で、棒焼けが発生し、生産性が不良で、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。さらに、Ｔｉを含有したが、Ｔｉが多いので、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２５は、鉄粉及び鉄合金粉のＦｅが少ないので、片溶けが発生した。さらに、金属Ｂ、Ｂ合金、及びＢ酸化物を一種或いは二種以上添加したが、Ｂ２Ｏ３換算値の合計が多いので、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２６は、金属弗化物が少ないので、スラグの被包性が不良で、ビード外観が不良であった。さらに、Ｍｇを添加したが、Ｍｇが多いので、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２７は、Ａｌを添加したが、Ａｌが多いので、ＰＷＨＴ後の溶着金属の吸収エネルギーが低かった。
溶接棒Ｎｏ．２８は、微量元素としてＣｕを添加したが、Ｃｕが多いので、高温割れが発生した。
Welding rod No. 20 had a large amount of Mo and a large total amount of Ti oxide converted into TiO2 , so the bead shape was convex, the tensile strength of the weld metal after PWHT was high, and the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 21 had a small amount of Mo and a small total amount of Ti oxide converted into TiO2 , so the bead shape was poor, the arc was unstable, and the tensile strength of the weld metal after PWHT was low.
Welding rod No. 22 had a large amount of Si and a small total Al2O3 converted value of Al oxide, so the bead shape was poor, the arc was unstable, and the absorbed energy of the deposited metal after PWHT was low.
Welding rod No. 23 had a small amount of metal carbonate and a large total of Na-converted value and K-converted value, so the arc was strong, there was a lot of spatter, and the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 24 had a low total Na-equivalent value and K-equivalent value, and a high Fe content in the iron powder and iron alloy powder, which resulted in an unstable arc, rod burn, poor productivity, and low absorbed energy of the weld metal after PWHT. Furthermore, although it contained Ti, the Ti content was high, so the absorbed energy of the weld metal after PWHT was low.
In the welding rod No. 25, the Fe content in the iron powder and iron alloy powder was low, so one-sided melting occurred. Furthermore, although one or more of metal B, B alloy, and B oxide were added, the total of the B2O3 equivalent value was high, so the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 26 had a low metal fluoride content, so the encapsulation of the slag was poor and the bead appearance was poor. Furthermore, Mg was added, but the amount of Mg was high, so the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 27 contained Al, but since the amount of Al was large, the absorbed energy of the weld metal after PWHT was low.
Welding rod No. 28 contained Cu as a trace element, but the Cu content was so high that hot cracking occurred.
Claims (4)
溶接棒全質量に対する前記被覆剤の質量割合が２５％以上４０％以下であり、
前記被覆剤が、被覆剤全質量に対する質量％で、
金属又は合金としてのＭｎ：２．０～５．０％、
金属又は合金としてのＮｉ：１．０～２．０％、
金属又は合金としてのＭｏ：０．３～１．５％、
金属又は合金としてのＳｉ：１．５～３．５％
Ｓｉ酸化物のＳｉＯ２換算値：４．０～８．０％
金属炭酸塩の合計：２５～４５％、
金属弗化物の合計：５～１５％、
Ｔｉ酸化物のＴｉＯ２換算値の合計：２．０～７．０％、
Ａｌ酸化物のＡｌ２Ｏ３換算値の合計：０．５～２．５％、
Ｍｇ酸化物のＭｇＯ換算値の合計：０．１～１．０％、
Ｃａ酸化物のＣａＯ換算値の合計：０．３０％以下、
Ｚｒ酸化物のＺｒＯ２換算値の合計：０．５～１．５％、
Ｎａ換算値とＫ換算値の合計：０．５～３．０％、
鉄粉及び鉄合金粉のＦｅ：２０～３５％、並びに
残部：前記Ｍｎから前記Ｆｅまでの成分を除く塗装剤の残部及び１．００％以下の不純物、
を含む鉄粉低水素系被覆アーク溶接棒。 The steel core wire includes a coating material that coats the steel core wire,
The mass ratio of the coating material to the total mass of the welding rod is 25% or more and 40% or less,
The coating agent is, in mass % based on the total mass of the coating agent,
Mn as metal or alloy: 2.0 to 5.0%;
Ni as metal or alloy: 1.0 to 2.0%,
Mo as metal or alloy: 0.3 to 1.5%,
Si as metal or alloy: 1.5 to 3.5%
Si oxide converted into SiO2 : 4.0 to 8.0%
Total metal carbonates: 25-45%,
Total metal fluorides: 5-15%,
Total of Ti oxides converted into TiO2 : 2.0 to 7.0%,
Sum of Al oxides converted into Al 2 O 3 : 0.5 to 2.5%,
Total Mg oxide converted into MgO: 0.1 to 1.0%,
Sum of Ca oxides converted into CaO: 0.30% or less,
Total Zr oxide converted into ZrO2 : 0.5 to 1.5%,
Sum of Na equivalent and K equivalent: 0.5 to 3.0%,
Fe in the iron powder and iron alloy powder: 20 to 35%, and the balance: the balance of the coating agent excluding the components from Mn to Fe, and impurities of 1.00% or less.
A low hydrogen-based iron powder covered metal arc welding electrode.
金属又は合金としてのＴｉ：３．５０％以下、並びに
金属Ｂ、Ｂ合金、及びＢ酸化物の各Ｂ２Ｏ３換算値の合計：０．６０％以下、
を含む請求項１に記載の鉄粉低水素系被覆アーク溶接棒。 The coating agent is, in place of a part of the components constituting the coating agent,
Ti as a metal or alloy: 3.50% or less; and The sum of the B2O3 converted values of metal B, B alloy, and B oxide: 0.60% or less.
The iron powder low hydrogen type covered metal arc welding electrode according to claim 1 .
金属又は合金としてのＭｇ：３．０％以下、及び
金属又は合金としてのＡｌ：３．５％以下、
の一方又は両方を含む請求項１又は請求項２に記載の鉄粉低水素系被覆アーク溶接棒。 The coating agent is, in place of a part of the components constituting the coating agent,
Mg as a metal or alloy: 3.0% or less; and Al as a metal or alloy: 3.5% or less;
3. The low hydrogen iron powder covered metal arc welding rod according to claim 1, further comprising one or both of the following:
（１）Ｌｉ：０．５％以下
（２）Ｖ、Ｎｂ、及びＴａ：一種又は二種以上の合計で０．５％以下
（３）Ｃｏ：０．５％以下
（４）Ｃｕ及びＢｉ：一種又は二種の合計で０．５％以下
（５）Ｃｒ：０．５％以下 The iron powder low hydrogen type covered metal arc welding electrode according to any one of claims 1 to 3, wherein the coating material contains, as a component other than the metal carbonate and the metal fluoride, one or more selected from the group consisting of the following (1) to (5), in mass% with respect to the total mass of the coating material, instead of a part of the components constituting the coating material:
(1) Li: 0.5% or less (2) V, Nb, and Ta: 0.5% or less in total of one or more of them (3) Co: 0.5% or less (4) Cu and Bi: 0.5% or less in total of one or more of them (5) Cr: 0.5% or less
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| JP2014151338A (en) | 2013-02-07 | 2014-08-25 | Kobe Steel Ltd | Low hydrogen type covered electrode |
| JP2015196183A (en) | 2014-04-02 | 2015-11-09 | 日鐵住金溶接工業株式会社 | Low hydrogen type coated electrode |
| JP2017001053A (en) | 2015-06-09 | 2017-01-05 | 株式会社神戸製鋼所 | Low hydrogen type covered arc welding rod |
| JP2017064740A (en) | 2015-09-29 | 2017-04-06 | 日鐵住金溶接工業株式会社 | Low-hydrogen type coated arc welding rod |
| CN111347190A (en) | 2018-12-20 | 2020-06-30 | 天津大桥焊材集团有限公司 | Ultralow-hydrogen high-strength steel welding electrode for welding refractory structural steel and preparation method thereof |
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2021
- 2021-03-31 JP JP2021061672A patent/JP7506017B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010227968A (en) | 2009-03-27 | 2010-10-14 | Kobe Steel Ltd | Low hydrogen based covered electrode |
| JP2014151338A (en) | 2013-02-07 | 2014-08-25 | Kobe Steel Ltd | Low hydrogen type covered electrode |
| JP2015196183A (en) | 2014-04-02 | 2015-11-09 | 日鐵住金溶接工業株式会社 | Low hydrogen type coated electrode |
| JP2017001053A (en) | 2015-06-09 | 2017-01-05 | 株式会社神戸製鋼所 | Low hydrogen type covered arc welding rod |
| JP2017064740A (en) | 2015-09-29 | 2017-04-06 | 日鐵住金溶接工業株式会社 | Low-hydrogen type coated arc welding rod |
| CN111347190A (en) | 2018-12-20 | 2020-06-30 | 天津大桥焊材集团有限公司 | Ultralow-hydrogen high-strength steel welding electrode for welding refractory structural steel and preparation method thereof |
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| JP2022157448A (en) | 2022-10-14 |
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