JPS6335355B2 - - Google Patents
Info
- Publication number
- JPS6335355B2 JPS6335355B2 JP14219984A JP14219984A JPS6335355B2 JP S6335355 B2 JPS6335355 B2 JP S6335355B2 JP 14219984 A JP14219984 A JP 14219984A JP 14219984 A JP14219984 A JP 14219984A JP S6335355 B2 JPS6335355 B2 JP S6335355B2
- Authority
- JP
- Japan
- Prior art keywords
- flux
- weld metal
- wire
- welding
- present
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000004907 flux Effects 0.000 claims description 59
- 238000003466 welding Methods 0.000 claims description 37
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 22
- 229910000831 Steel Inorganic materials 0.000 claims description 18
- 239000010959 steel Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 15
- 229910052782 aluminium Inorganic materials 0.000 claims description 14
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 2
- 229910052593 corundum Inorganic materials 0.000 claims 1
- 229910001845 yogo sapphire Inorganic materials 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 description 51
- 239000002184 metal Substances 0.000 description 51
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 28
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 21
- 239000011324 bead Substances 0.000 description 17
- 238000005336 cracking Methods 0.000 description 17
- 230000000694 effects Effects 0.000 description 17
- 239000000395 magnesium oxide Substances 0.000 description 15
- 239000003795 chemical substances by application Substances 0.000 description 13
- 229910004261 CaF 2 Inorganic materials 0.000 description 11
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 239000002994 raw material Substances 0.000 description 9
- 238000007711 solidification Methods 0.000 description 9
- 230000008023 solidification Effects 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 8
- 239000002893 slag Substances 0.000 description 8
- 229910000990 Ni alloy Inorganic materials 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 229910001512 metal fluoride Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 229910052721 tungsten Inorganic materials 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910052761 rare earth metal Inorganic materials 0.000 description 4
- 229910003296 Ni-Mo Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 229910052735 hafnium Inorganic materials 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- DDTIGTPWGISMKL-UHFFFAOYSA-N molybdenum nickel Chemical compound [Ni].[Mo] DDTIGTPWGISMKL-UHFFFAOYSA-N 0.000 description 3
- 235000019353 potassium silicate Nutrition 0.000 description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- 229910052726 zirconium Inorganic materials 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000010436 fluorite Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052596 spinel Inorganic materials 0.000 description 2
- 239000011029 spinel Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910016036 BaF 2 Inorganic materials 0.000 description 1
- 229910019589 Cr—Fe Inorganic materials 0.000 description 1
- 229910017082 Fe-Si Inorganic materials 0.000 description 1
- 229910017133 Fe—Si Inorganic materials 0.000 description 1
- 229910017305 Mo—Si Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910001748 carbonate mineral Inorganic materials 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 235000012204 lemonade/lime carbonate Nutrition 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000010309 melting process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- -1 siyamoto Inorganic materials 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 239000010456 wollastonite Substances 0.000 description 1
- 229910052882 wollastonite Inorganic materials 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/3601—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
- B23K35/3603—Halide salts
- B23K35/3605—Fluorides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3033—Ni as the principal constituent
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Arc Welding In General (AREA)
- Nonmetallic Welding Materials (AREA)
Description
〔産業上の利用分野〕
本発明は、5.5Ni鋼；9Ni鋼等の低温用Ni合金
鋼の溶接に用いるサブマージアーク溶接法の改良
に係り、更に詳しくは、特定成分のワイヤ、フラ
ツクスを組み合わせる事により優れた耐割れ性溶
接金属を生成するサブマージアーク溶接法に関す
るものである。
〔従来の技術〕
近年、LNGが一般的なエネルギー源として活
用されるに至り、LNGタンクが各所で建設され、
このため、9Ni鋼等のサブマージアーク溶接が頻
繁に行なわれて、その重要性が増大している。
従来、低温用Ni合金鋼のサブマージアーク溶
接法においては、低温靭性および強度の観点か
ら、Ni―Mo―Ｗ、Ni―Cr―FeあるいはNi―
Mo―Cr系高Ni合金ワイヤと、金属弗化物、
CaO、MgO、SiO2等を主成分とし、これにSi、
Al等の脱酸剤を添加した焼成形フラツクスの組
み合わせが用いられている。
例えば、特公昭47−8123号公報には10〜50wt.
％の合金を含有するNi基ワイヤと組み合わせる
フラツクスとして、炭酸カルシウム、酸化マグネ
シウム、螢石、ジルコン砂、ケイ砂、Fe―Siお
よび合金剤からなる9Ni鋼用のサブマージアーク
溶接用フラツクス、特公昭56−53474号公報には
MgO、Al2O3、CaCO3および脱酸剤を含有する
横向溶接用焼成形フラツクス、特公昭56−53475
号公報には、SiO2、CaO、MgO、Al2O3および
金属弗化物を含有し、TiO2を5wt.％以下とし、
かつ、脱酸剤を10wt.％以下含有する潜弧溶接用
フラツクス、特開昭55−22407号公報には多量の
金属弗化物と脱酸剤として、特定量のAlもしく
はAl＋Siを添加した、焼成形フラツクス、特開
昭58−110192号公報には多量の金属弗化物とAl
および希土類元素を添加した低温用サブマージア
ーク溶接用フラツクス、特開昭58−61993号公報
には特定量のNi、Mo、Alを含有するワイヤが、
又、特公昭59−6756号公報には特定量のCaCO3、
CaF2、MgO、SiO2、Alを含有するフラツクスと
特定量のNi、Al、Moを含有するワイヤを組み合
わせて行なうサブマージアーク溶接法が開示され
ている。
ところが、以上のような溶接材料あるいは溶接
法においては、低温靭性、引張強さ等の基本特性
についてはよく検討されているが高Ni―Mo系溶
接金属において粒界に発生しやすいミクロ割れ防
止という観点からは充分に検討されたものではな
く、満足出来るもではない。即ち、高Ni―Mo系
ワイヤを用いた溶接においては、オーステナイト
単一組織の溶接金属が生成されるが、この場合(1)
フラツクス中に脱酸剤として添加されるSi、ある
いはスラグ剤のSiO2から還元されたSiが濃縮し、
MoおよびNiとの間に低融点共晶物を生成しやす
い事、(2)溶接金属中の酸素が粒界に酸化物を形成
し、粒界脆化を起す事、の２点により、後続パス
により熱影響および熱歪を受けた溶接金属内にミ
クロ割れが発生しやすい問題がある。このような
ミクロ割れを防止するにはSiO2およびSi等の有
害成分のフラツクスあるいはワイヤへの添加量を
極力制限する事および耐割れ性を向上する成分を
積極的に添加する事を併せて行なう事が極めて重
要であるが、このような観点からは従来の溶接材
料はいずれも満足し得るものではない。
又、従来より高Ni合金ワイヤによる溶接部に
おいては特に初層溶接金属の中央部に凝固割れが
発生し易い事が知られており、これは特にCrを
多量に含有するワイヤの場合に発生するものであ
り、この点からも充分な対策が望まれるものであ
る。
〔発明が解決しようとする問題点〕
本発明は高Ni―Mo系合金ワイヤを用いたオー
ステナイト単一組織溶接金属の粒界に発生しやす
いミクロ割れおよび初層溶接金属の凝固割れを完
全に防止すると共に、優れたビード外観およびＸ
線性能を得る事の出来るNi合金鋼のサブマージ
アーク溶接の提供を目的とするものである。
〔問題点を解決するための手段〕
以下、本発明について詳細に説明する。
まず、本発明に用いるワイヤはNi；60〜88wt.
％、Mo；10〜38wt.％、Al；0.10〜2.0wt.％を含
有し、かつ、Si；0.15wt.％以下、Cr；5.0wt.％以
下に限定するものであるが、NiおよびMoは低温
用鋼ワイヤとして低温靭性および強度の基本特性
を具備するために必須な成分であり、又、Al、
Si、Crについては本発明の目的とするミクロ割
れおよび凝固割れ防止に極めて重要な要件となる
ものである。
これらワイヤに添加する成分について以下に順
次説明する。
Ni；Niは低温用鋼溶接金属の低温靭性を確保
するために必須であり本発明法による溶接金属の
基本成分である。LNGタンクの継手溶接金属に
対しては、通常−196℃において3.5Kgf.m以上の
衝撃値が要求されるが、これを充分に満足するに
はワイヤ中のNiが、60wt.％以上である事が必要
である。一方、溶接金属の強度の確保という点か
らはNi以外にMo、Ｗ、Cr等の強化元素を添加す
る事が必要である。従つて、このような他の元素
の添加を考慮するとワイヤ中のNiは88wt.％以下
である事が必要である。結局、本発明におけるワ
イヤ中のNi含有量は60〜88wt.％である事が必要
である。
Mo；Moは溶接金属の強度を確保するために
添加するものであるが、Cr等の強化元素と比較
して、初層溶接金属に発生しやすい凝固割れ感受
性を低下する効果を有し、極めて有用な成分であ
る。ワイヤ中のMoが10wt.％未満では上記効果
が認められず、又38wt.％を超えると溶接金属中
の低温靭性が劣化するので好ましくない。
AlおよびSi；Alは優れた脱酸作用を呈する元
素であり、多量の添加により溶接金属中の酸素を
著しく低減し、粒界のミクロ割れ防止に極めて有
効である。即ち、Al添加による脱酸効果はフラ
ツクスへのCaF2、CaOおよびMgO等の塩基性成
分添加との組み合わせにより通常の溶接金属酸素
量200〜300ppmを40〜70ppm迄低減する効果があ
る。さらにAlには脱酸作用ばかりでなく、それ
自体が優れた粒界強化作用を有しミクロ割れ防止
に極めて有効に作用する事を見出した。
一方Siも優れた脱酸剤であり溶接金属中の酸素
量低減には有効であるが、Siの場合は溶接金属の
粒界に偏析し、酸化物を形成して粒界脆化を惹起
すると共にNi―Mo―Si系低融点共晶物を生成
し、溶接金属が後続パスにより加熱された場合、
粒界に液化反応を起しミクロ割れを発生せしめる
原因となる。従つて、SiはＯと共にミクロ割れに
対し極めて有害であり極力低減する必要がある。
即ち、粒界のミクロ割れを防止するには溶接金属
中のSiを極力低減し、かつ、Alを積極的に添加
する事が有効である。第１図はミクロ割れ発生数
に及ぼす溶接金属中のAlおよびSi含有量の影響
を示すものであり、ミクロ割れはSiの増加に伴い
発生し、又、Alの増加により防止し得る事が判
る。なお、第１図における溶接およびミクロ割れ
テストの要領は溶接材料以外は後述の実施例と同
様であり、溶接姿勢は横向で実施した。
ところで、溶接金属中のSiは、ワイヤおよびフ
ラツクス中のSiならびにフラツクス中のSiO2の
還元（SiO2→Si＋2O）により添加されるもので
あるが、このうちフラツクス中のSi以外は皆無に
する事は難しい。即ち、ワイヤにおいては溶解過
程において、原料および炉材から侵入するもので
あり、又鍛造性の向上等の観点から止むを得ず若
干のSiを添加する事もある。又フラツクス中の
SiO2においても同様で、原料中の不純物として
のSiO2、焼成フラツクスとして原料を造粒する
場合に用いる水ガラス中のSiO2あるいはビード
外観等の改善のためにスラグ生成剤として止むを
得ず添加するSiO2等である。AlおよびSiのミク
ロ割れに及ぼす影響は以上のようであるが、結論
としては、前述の如く第１図に示した如く溶接金
属中にAlを0.2wt.％以上添加する事により溶接金
属中のSiが0.6wt.％程度迄割れが発生せず許容さ
れる事を明らかにした。即ち、本発明法において
は、ミクロ割れ防止対策として上記範囲即ちSi
0.6wt.％、Al0.20wt.％の溶接金属を生成しよ
うとするものである。
そこで、以上のような溶接金属の生成のための
ワイヤのAlの添加量は検討の結果、0.10〜2.0wt.
％が必要であるが事が判明した。溶接金属への
Alの添加はワイヤばかりでなくフラツクスから
も添加する事が可能であり極めて重要な手段であ
るがワイヤにAlを添加せずフラツクス中に金属
粉として添加するのみでは、溶接金属中のAl量
が溶接条件の変動を受けやすい事、又、フラツク
スの繰返し使用により、Alが酸化変質する事な
どにより溶接金属中のAl量が不安定であり、一
定量のAlをワイヤ中に添加し、溶接金属へのAl
の安定添加を行なう事がミクロ割れ防止の観点か
ら必須である。ワイヤ中のAl含有量が0.10wt.％
未満では溶接金属中のAlを安定して0.2wt.％以上
にする事が難しい。又、ワイヤ中のAl含有量が
2.0wt.％を超えると熱間鍛造性が劣化し、ワイヤ
の製造が困難となる。従つてワイヤ中のAl含有
量は0.10〜2.0wt.％である事が必要である。
一方、ワイヤ中のSi含有量であるが、溶接金属
中のSiを0.60wt.％以下迄低減するためには、
0.15wt.％以下とする事が必要である。即ち、溶
接金属中のSiはフラツクス中のSiおよびSiO2から
も移行する。本発明においては後述の如くフラツ
クス中にはSiを実質的に添加せず、又SiO2に関
してはフラツクス全体に対し8wt.％以下に制限す
るものである。このSiO2により溶接金属中のSi
は0.45wt.％程度迄成り得るものであり、又ワイ
ヤ中のSiの60〜80％は溶接金属中に移行する。従
つて、ワイヤ中のSi含有量は0.15wt.％以下に制
限する事が必要である。
Cr；Crは通常この種の溶接金属においては、
強度の増加のためMoと共に多量に添加される
が、一方、Crは前述のミクロ割れとは異なるタ
イプの割れ、即ち、初層溶接金属の中央部に凝固
割れを起しやすいものであり、その上検討の結果
によればAlとの共存において耐割れ性がさらに
劣化する事が判明し、Alと積極的に添加する本
発明法においてはワイヤ中のCrを制限する事が
極めて重要である。又、Crは前述からのミクロ
割れに対しても悪影響を有し、若干のミクロ割れ
の発生も有り得る事が判明した。以上のような割
れ防止の観点から本発明法ではワイヤ中のCr含
有量は5.0wt.％以下に限定する事が必要である。
以上が、本発明で特に定めるワイヤ成分および
含有量であるが、Ｐ、Ｓ等の不可避不純物は勿論
の事、使用目的によつて他の成分を含む事も本発
明に含まれる。例えば、溶接金属の強度を高める
ためにＣ、Ｗ、Co、Mn等の添加が効果があるが
Ｃは0.04wt.％、Ｗは10wt.％、Coは10wt.％を超
えると低温靭性が低下し、特にＣは靭性において
ばかりでなく、耐割れ性を損なうものであり
0.04wt.％以下が好ましい。Mnは5wt.％を超える
と溶接金属の靭性が劣化する。
上記合金元素の他に、Niを節約する意味でも
Feも添加する事も出来るが、20wt.％を超えると
強度および靭性が低下するので好ましくない。従
つて、各々の上限がＣ：0.04wt.％、Ｗ；10wt.
％、Co；10wt.％、Mn；5wt.％、Fe；20wt.％で
あれば、これらを１種又は２種以上含んでも本発
明の特性を損なうものではない。
さらに、脱酸能力を高めるために、Ti、Mg、
Ca、Ｖ、Zr、Ｙ、Hf、REM等の添加が効果があ
るが、Mgは0.05wt.％、Caは0.05wt.％、Ｖは
0.2wt.％、Zrは0.2wt.％、Ｙは0.1wt.％、Hfは
0.1wt.％、REMは0.1wt.％を超えると溶接時の凝
固割れ感受性およびミクロ割れ感受性が劣化し、
Tiは0.5wt.％を超えると耐割れ性ばかりでなくス
ラグのこびりつきも生じやすい。従つて、各々の
上限が、Ti；0.5wt.％、Mg；0.05wt.％、Ca；
0.05wt.％、Ｖ；0.2wt.％、Zr；0.2wt.％、Ｙ；
0.1wt.％、Hf；0.1wt.％、REM；0.1wt.％であれ
ばこれらを１種又は２種以上含んでも本発明の特
性を損なうものではない。
本発明におけるワイヤは以上述べた如く、Ni
―Mo系合金においてAlを適量添加し、Siおよび
Crの含有量を限定することで溶接金属の粒界に
発生するミクロ割れおよび凝固割れ防止を行なう
ものである。
ところで、本発明に用いるフラツクスは上記ワ
イヤと組み合わせてミクロ割れ防止を確実にし、
かつ、すぐれたビード外観が得られるものであ
り、そのために、CaF2、CaO及び／又はMgO、
Al2O3、SiO2、AlおよびSiの含有量について特定
する事が必要である。
以下に各成分の添加理由について述べる。
CaF2；CaF2はスラグの塩基度を上げ、溶接金
属の酸素量を著しく低減するもので、本発明の如
く低酸素溶接金属を生成し、ミクロ割れを防止す
るためのフラツクス成分としては不可欠のもので
ある。さらに、本発明の目的とするNi合金鋼の
溶接は比較的小入熱で溶接が行なわれるが、この
ような溶接の場合には、フラツクスの溶融点を低
く設定する事が必要で、このためには融点の低い
CaF2を主成分とする事が極めて有効で、これに
より優れたビード外観を得る事が判明した。
CaF2のフラツクス全体に対する添加量が30wt.％
未満ではその効果がなく、又、70wt.％を超える
とスラグの流動性が過大となり凝固波が不安定で
かえつてビード外観が劣化する。
CaO及び／又はMgO；CaOおよびMgOはいず
れも強塩基性成分でCaF2と共に溶接金属の酸素
量の低減に有効である。さらに、CaO、MgOは
耐火性の大きい成分であり、溶融点の低いCaF2
を多量に含有するフラツクスの溶融特性を調整
し、ビード外観を整えるのに有効である。このよ
うな効果はCaO及び／又はMgOが8wt.％未満で
は得られず、又30wt.％を超えるとフラツクスが
溶け難くビード表面が平滑さを失い、又、アンダ
ーカツト等の欠陥も生しやすくなる。
Al2O3；Al2O3も又溶融点が高く溶融スラグの
流動性を調整し、ビード外観を整えるのに有効で
ある。このようなAl2O3の効果は、本発明法を横
向多層溶接に用いる時に重要であり、フラツクス
の基本成分がCaF2―CaO―MgO系のみではビー
ド同志の重なり部がスムースでなく凹凸が生じる
が、Al2O3の添加によりビード同志のなじみが良
好となりスムースな多層盛ビード面が得られる。
Al2O3のこのような効果はフラツクス全体に対
して5wt.％未満では得られず、又35wt.％を超え
るとスラグが溶接金属中に巻き込まれやすくな
り、Ｘ線性能が劣化するので好ましくない。
SiO2；SiO2はスラグの粘性を調整し、ビード
外観を改善するのに極めて有効であるが、一方、
SiO2はアーク雰囲気中で還元され、溶接金属中
のSiおよび酸素を増大せしめミクロ割れを発生せ
しめる。従つて、ワイヤからのSiの移行も考える
と本発明におけるフラツクスにおいては、フラツ
クス全体に対し、8.0wt.％以下に限定する事が必
要である。焼成形フラツクスにおいては、造粒時
に固着剤として水ガラスを用いるが、この中には
多量のSiO2が含有されており、通常のフラツク
スにおいては３〜4wt.％のSiO2が混入する。従
つて、本発明のフラツクスにおいては、粉末原料
として添加し得るSiO2分は、4.0wt.％以下であ
る。
Si；本発明はミクロ割れ防止の観点から、溶接
金属中のSiを可及的に少くするものであり、脱酸
剤としてのSiは実質的に用いない。脱酸剤の機能
は殆んど、Alによつて達成する。
Al；Alは前述の如く、ミクロ割れ防止の観点
から必須成分であり、ワイヤからと共にフラツク
スからも添加する事により溶接金属中のAl含有
量を安定化するものである。又、フラツクスから
のAlの添加は、ブローホール、ポツクマーク等
のガス欠陥を防止するのに重要であり、このよう
な効果はワイヤからの添加のみでは得られ難い。
フラツクスへのAlの添加量は組み合わせるワイ
ヤのAl含有量との関係で選択し得るが、フラツ
クス全体に対し、0.5〜7wt.％が良好で、0.5wt.％
未満では溶接金属中にガス欠陥が発生し易く、
又、7wt.％を超えると、ビード外観が損なわれ好
ましくない。
以上、本発明におけるフラツクスの必須成分に
ついて説明したが、これら成分の添加原料は単独
物質と共に上記成分を含有する化合物、鉱石ある
いは溶融形フラツクスで添加する事が出来る。即
ち、用いる原料としては以下のようである。
CaF2；螢石、溶融形フラツクス等、CaO；炭
酸石灰、珪灰石、溶融形フラツクス等、MgO；
マグネシアクリンカー、スピネル、溶融形フラツ
クス等、Al2O3；アルミナ、シヤモツト、スピネ
ル、溶融形フラツクス等。Al；金属Al、Fe―Al
等、である。
なお、本発明におけるフラツクスにおいては、
上記必須成分と共に、CO2相当量が0.5〜4.0wt％
の範囲でCaCO3、BaCO3等の炭酸塩鉱物を添加
すると、これらは、アーク空胴中の水素分圧を減
少させ、水素に起因する微小ブローホールの防止
に有効である。
その他のフラツクス成分としては、通常の溶接
用原料として用いられるBaF2、MgF2、NaF等
の金属弗化物、MnO、ZrO2等の金属酸化物等を
用いる事が出来る。
〔実施例〕
まず、第１表に示す組成の合金を真空溶解炉に
て作製し、鍛造、圧延および線引きを行なつて
2.4mmφ又は3.2mmφのワイヤを作製した。但し、
Ｗ―13についてはワイヤの製造過程において鍛造
中に割れが発生し、ワイヤに仕上げる事が出来な
かつた。
第１表に示したワイヤうち、Ｗ―１〜Ｗ―７は
本発明に用いるワイヤ、Ｗ―８〜Ｗ―15は本発明
法の効果を明確にするための比較例に用いたワイ
ヤである。
次に第２表に示す組成のサブマージアーク溶接
用フラツクスを作製した。この場合、原料とし
て、通常の溶接フラツクス原料として用いられる
鉱石粉、合成物あるいは金属粉の他に溶融形フラ
ツクス粉およびアルミナセメント粉を用いた。
フラツクスはいずれも固着剤として水ガラスを
用いて造粒し、500℃×1hr.の条件で焼成した焼
成形フラツクスである。なお、第２表のフラツク
スのうちＦ―１〜Ｆ―５は本発明法に用いたフラ
ツクス、Ｆ―６〜Ｆ―10は比較例に用いたもので
ある。
以上のようなワイヤおよびフラツクスを用い、
第３表に示す鋼板および第４表および第２図、第
３図に示す溶接条件により19種のサブマージアー
ク溶接を実施した。溶接長は2mである。
第５表に実施した溶接におけるフラツクス、ワ
イヤ、鋼板および溶接条件の組み合わせおよび溶
接部の確性試験結果を示す。
溶接部の確性は、まずビード外観を観察した
後、第３図に示すように余盛りビードを板面（第
３図d1，d2，d3，d4）まで研削しＸ線透過試験
（JIS Ｚ 3104による。）を行ない、次に板面およ
びさらに２mm削つた面（第３図l1，l2，l3，l4）に
つき浸透探傷試験を行ない、ミクロ割れの有無を
調査した。第５表には溶接部の表裏の割れ発生数
の合計を1m当りの発生数で示した。その後、残
つた溶接金属より引張試験片g1（JIS Ｚ 3111A2
号）および衝撃試験片f1（JIS Ｚ 2202 ４号）を
採取しそれぞれの試験を行なつた。衝撃試験は
LNGタンク溶接部（９％Ni鋼の継手部）に要求
される−196℃で行なつた。
以上の溶接部の確性結果を第５表右欄に示す。
実施例のうち、No.１〜No.７は本発明の効果により
優れた溶接部を得る事が出来たが、No.８〜No.19は
第５表にその個々の理由について示した如く、ワ
イヤ中のNi、Mo、Al、およびCr含有量の不適
正さらに、フラツクス中のCaF2、CaO＋MgO、
SiO2、Al2O3およびAl含有量の不適正、フラツク
スへのSiの添加によりビード外観不良、ミクロ割
れあるいは凝固割れの発生、機械的性質不満足あ
るいはＸ線判定結果不良の問題が発生した。
〔本発明の効果〕
以上、述べた如く本発明は5.5Ni鋼、9Ni鋼等
の低温用Ni合金鋼のサブマージアーク溶接にお
いてミクロ割れおよび凝固割れが発生せず、か
つ、優れた機械的性質の溶接部が得られると共
に、ビード外観およびＸ線性能も充分満足し得る
溶接法を提供するものである。
[Industrial Application Field] The present invention relates to an improvement of the submerged arc welding method used for welding low-temperature Ni alloy steels such as 5.5Ni steel and 9Ni steel. The present invention relates to a submerged arc welding method that produces a weld metal with superior crack resistance. [Conventional technology] In recent years, LNG has come to be used as a general energy source, and LNG tanks are being constructed in various places.
For this reason, submerged arc welding of 9Ni steel and the like is frequently performed, and its importance is increasing. Conventionally, in the submerged arc welding method of Ni alloy steel for low temperature use, Ni-Mo-W, Ni-Cr-Fe or Ni-
Mo-Cr based high Ni alloy wire and metal fluoride,
The main components are CaO, MgO, SiO 2 , etc., and Si,
A combination of sintered flux to which a deoxidizing agent such as Al is added is used. For example, in Japanese Patent Publication No. 47-8123, 10 to 50 wt.
Flux for submerged arc welding for 9Ni steel, consisting of calcium carbonate, magnesium oxide, fluorite, zircon sand, silica sand, Fe-Si, and alloying agent, as a flux to be combined with Ni-based wire containing % alloy. −53474 publication
Sintered flux for horizontal welding containing MgO, Al 2 O 3 , CaCO 3 and deoxidizing agent, Japanese Patent Publication No. 56-53475
The publication contains SiO 2 , CaO, MgO, Al 2 O 3 and metal fluoride, and TiO 2 is 5 wt.% or less,
Moreover, a flux for submerged arc welding containing 10 wt.% or less of a deoxidizing agent, JP-A No. 55-22407, is a sintered flux containing a large amount of metal fluoride and a specific amount of Al or Al+Si as a deoxidizing agent. A large amount of metal fluoride and Al
and a flux for low-temperature submerged arc welding with the addition of rare earth elements.
Also, in Japanese Patent Publication No. 59-6756, a specific amount of CaCO 3 ,
A submerged arc welding method is disclosed in which a flux containing CaF 2 , MgO, SiO 2 , and Al is combined with a wire containing specific amounts of Ni, Al, and Mo. However, although the basic properties of the welding materials and welding methods mentioned above, such as low-temperature toughness and tensile strength, have been well studied, there is a problem in preventing microcracks that tend to occur at grain boundaries in high Ni-Mo weld metals. From this point of view, it has not been sufficiently studied and is not satisfactory. That is, in welding using a high Ni-Mo wire, a weld metal with a single austenite structure is produced, but in this case (1)
Si added to flux as a deoxidizing agent or Si reduced from SiO 2 as a slag agent is concentrated,
(2) Oxygen in the weld metal forms oxides at grain boundaries, causing grain boundary embrittlement. There is a problem in that microcracks are likely to occur in the weld metal that has been affected by heat and thermal strain due to passes. To prevent such microcracks, it is necessary to limit the amount of harmful components such as SiO 2 and Si added to the flux or wire as much as possible, and to actively add components that improve cracking resistance. This is extremely important, but none of the conventional welding materials are satisfactory from this point of view. Furthermore, it has been known that solidification cracking is particularly likely to occur in the center of the first layer weld metal in welds using high Ni alloy wire, and this occurs especially in the case of wire containing a large amount of Cr. Therefore, sufficient countermeasures are desired from this point of view as well. [Problems to be solved by the invention] The present invention completely prevents micro-cracks that tend to occur at the grain boundaries of austenitic single-structure weld metal using high Ni-Mo alloy wire and solidification cracks in the first layer weld metal. At the same time, excellent bead appearance and
The purpose of this project is to provide submerged arc welding of Ni alloy steel that can obtain good wire performance. [Means for Solving the Problems] The present invention will be described in detail below. First, the wire used in the present invention is Ni; 60 to 88wt.
%, Mo: 10 to 38 wt.%, Al: 0.10 to 2.0 wt.%, and limited to Si: 0.15 wt.% or less, Cr: 5.0 wt.% or less, but Ni and Mo is an essential component for low-temperature steel wire to have the basic characteristics of low-temperature toughness and strength.
Si and Cr are extremely important requirements for preventing microcracking and solidification cracking, which is the objective of the present invention. The components added to these wires will be sequentially explained below. Ni: Ni is essential for ensuring the low-temperature toughness of the low-temperature steel weld metal, and is a basic component of the weld metal produced by the method of the present invention. The weld metal for LNG tank joints is normally required to have an impact value of 3.5Kgf.m or more at -196℃, but to fully satisfy this, the Ni content in the wire must be 60wt.% or more. things are necessary. On the other hand, in order to ensure the strength of the weld metal, it is necessary to add reinforcing elements such as Mo, W, and Cr in addition to Ni. Therefore, taking into consideration the addition of such other elements, it is necessary that the Ni content in the wire be 88 wt.% or less. Ultimately, the Ni content in the wire in the present invention needs to be 60 to 88 wt.%. Mo: Mo is added to ensure the strength of the weld metal, but compared to reinforcing elements such as Cr, it has the effect of reducing the susceptibility to solidification cracking that tends to occur in the initial layer weld metal, and is extremely effective. It is a useful ingredient. If the Mo content in the wire is less than 10 wt.%, the above effect will not be observed, and if it exceeds 38 wt.%, the low temperature toughness in the weld metal will deteriorate, which is not preferable. Al and Si: Al is an element that exhibits an excellent deoxidizing effect, and when added in a large amount, it significantly reduces oxygen in the weld metal and is extremely effective in preventing microcracks at grain boundaries. That is, the deoxidizing effect of Al addition has the effect of reducing the usual weld metal oxygen content from 200 to 300 ppm to 40 to 70 ppm when combined with the addition of basic components such as CaF 2 , CaO and MgO to the flux. Furthermore, it was discovered that Al not only has a deoxidizing effect, but also has an excellent grain boundary strengthening effect and is extremely effective in preventing microcracking. On the other hand, Si is also an excellent deoxidizing agent and is effective in reducing the amount of oxygen in weld metal, but in the case of Si, it segregates at the grain boundaries of weld metal, forming oxides and causing grain boundary embrittlement. When the weld metal is heated in the subsequent pass, a Ni-Mo-Si low melting point eutectic is generated.
This causes a liquefaction reaction at grain boundaries and causes micro-cracking. Therefore, together with O, Si is extremely harmful to microcracks and needs to be reduced as much as possible.
That is, in order to prevent microcracks at grain boundaries, it is effective to reduce Si in the weld metal as much as possible and to actively add Al. Figure 1 shows the influence of Al and Si contents in the weld metal on the number of microcracks that occur, and it can be seen that microcracks occur as Si increases, and that they can be prevented by increasing Al. . The welding and micro-cracking tests shown in FIG. 1 were performed in the same manner as in the examples described later except for the welding materials, and the welding was carried out in a horizontal position. By the way, Si in the weld metal is added by reducing Si in the wire and flux and SiO 2 in the flux (SiO 2 → Si + 2O), but it is important to eliminate all of these except for the Si in the flux. is difficult. That is, in the wire, Si enters from the raw material and furnace material during the melting process, and a small amount of Si may be unavoidably added from the viewpoint of improving forgeability. Also, in the flux
The same goes for SiO 2 , SiO 2 as an impurity in raw materials, SiO 2 in water glass used when granulating raw materials as firing flux, or as a slag forming agent to improve bead appearance etc. SiO 2 etc. to be added. The effects of Al and Si on microcracking are as described above, but the conclusion is that by adding 0.2wt.% or more of Al to the weld metal, as shown in Figure 1, It was revealed that Si content up to about 0.6 wt.% was tolerated without cracking. That is, in the method of the present invention, the above range, that is, Si
The aim is to produce a weld metal containing 0.6wt.% and Al 0.20wt.%. Therefore, the amount of Al added to the wire for producing the above-mentioned weld metal was determined to be 0.10 to 2.0wt.
It turns out that % is necessary. to weld metal
Al can be added not only from the wire but also from the flux, and is an extremely important means. However, if Al is not added to the wire and only added as metal powder to the flux, the amount of Al in the weld metal will decrease. The amount of Al in the weld metal is unstable due to the fact that it is susceptible to changes in welding conditions, and due to the oxidation and deterioration of Al due to repeated use of flux, a certain amount of Al is added to the wire and the weld metal Al to
It is essential from the viewpoint of preventing micro-cracks to stably add . Al content in wire is 0.10wt.%
If it is less than 0.2 wt.%, it is difficult to stably maintain Al in the weld metal to 0.2 wt.% or more. Also, the Al content in the wire is
If it exceeds 2.0wt.%, hot forgeability deteriorates, making it difficult to manufacture wire. Therefore, the Al content in the wire needs to be 0.10 to 2.0 wt.%. On the other hand, in order to reduce the Si content in the weld metal to 0.60wt.% or less,
It is necessary to keep it below 0.15wt.%. That is, Si in the weld metal also migrates from Si and SiO 2 in the flux. In the present invention, as described later, Si is not substantially added to the flux, and SiO 2 is limited to 8 wt.% or less based on the entire flux. This SiO 2 removes Si in the weld metal.
can be up to about 0.45wt.%, and 60 to 80% of the Si in the wire migrates into the weld metal. Therefore, it is necessary to limit the Si content in the wire to 0.15wt.% or less. Cr; Cr is usually used in this type of weld metal.
Cr is added in large quantities along with Mo to increase strength, but on the other hand, Cr tends to cause a type of cracking different from the micro-cracking mentioned above, that is, solidification cracking in the center of the first layer weld metal, and According to the results of the above study, it has been found that the cracking resistance is further deteriorated in the coexistence with Al, and it is extremely important to limit the amount of Cr in the wire in the method of the present invention, which actively adds Al. It has also been found that Cr has an adverse effect on the micro-cracks mentioned above, and that some micro-cracks may occur. From the viewpoint of preventing cracking as described above, in the method of the present invention, it is necessary to limit the Cr content in the wire to 5.0 wt.% or less. The above are the wire components and contents specifically defined in the present invention, but the present invention also includes the inclusion of other components depending on the purpose of use, as well as inevitable impurities such as P and S. For example, adding C, W, Co, Mn, etc. is effective in increasing the strength of weld metal, but low-temperature toughness decreases when C exceeds 0.04 wt.%, W exceeds 10 wt.%, and Co exceeds 10 wt.%. However, C in particular impairs not only toughness but also cracking resistance.
It is preferably 0.04wt.% or less. When Mn exceeds 5wt.%, the toughness of the weld metal deteriorates. In addition to the above alloying elements, in order to save Ni
Fe can also be added, but if it exceeds 20 wt.%, the strength and toughness will decrease, which is not preferable. Therefore, the upper limits of each are C: 0.04wt.% and W: 10wt.
%, Co: 10 wt.%, Mn: 5 wt.%, Fe: 20 wt.%, even if one or more of these are included, the characteristics of the present invention will not be impaired. Furthermore, in order to increase the deoxidizing ability, Ti, Mg,
Addition of Ca, V, Zr, Y, Hf, REM, etc. is effective, but Mg is 0.05wt.%, Ca is 0.05wt.%, V is
0.2wt.%, Zr is 0.2wt.%, Y is 0.1wt.%, Hf is
If it exceeds 0.1wt.% and REM exceeds 0.1wt.%, solidification cracking susceptibility and microcracking susceptibility during welding will deteriorate.
When Ti exceeds 0.5wt.%, it not only has poor cracking resistance but also tends to cause slag sticking. Therefore, each upper limit is Ti; 0.5wt.%, Mg; 0.05wt.%, Ca;
0.05wt.%, V; 0.2wt.%, Zr; 0.2wt.%, Y;
As long as they are 0.1 wt.%, Hf: 0.1 wt.%, and REM: 0.1 wt.%, the characteristics of the present invention will not be impaired even if one or more of these are included. As mentioned above, the wire in the present invention is made of Ni
- Adding an appropriate amount of Al to Mo-based alloys to improve Si and
By limiting the Cr content, microcracks and solidification cracks that occur at the grain boundaries of the weld metal are prevented. By the way, the flux used in the present invention is used in combination with the above wire to ensure prevention of micro-cracking.
Moreover, an excellent bead appearance can be obtained, and for this purpose, CaF 2 , CaO and/or MgO,
It is necessary to specify the contents of Al 2 O 3 , SiO 2 , Al and Si. The reasons for adding each component will be described below. CaF 2 ; CaF 2 increases the basicity of slag and significantly reduces the amount of oxygen in weld metal, and is essential as a flux component for producing low-oxygen weld metal and preventing microcracking as in the present invention. It is something. Furthermore, welding of Ni alloy steel, which is the object of the present invention, is performed with a relatively low heat input, but in such welding, it is necessary to set the melting point of the flux low; has a low melting point
It has been found that using CaF 2 as the main component is extremely effective and provides an excellent bead appearance.
The amount of CaF 2 added to the entire flux is 30wt.%
If it is less than 70wt.%, there is no effect, and if it exceeds 70wt.%, the fluidity of the slag becomes excessive, causing unstable coagulation waves and deteriorating the appearance of the bead. CaO and/or MgO: Both CaO and MgO are strong basic components and, together with CaF 2 , are effective in reducing the amount of oxygen in the weld metal. Furthermore, CaO and MgO are highly refractory components, and CaF2 has a low melting point.
It is effective for adjusting the melting characteristics of fluxes containing a large amount of and for improving the bead appearance. Such an effect cannot be obtained when CaO and/or MgO is less than 8 wt.%, and when it exceeds 30 wt.%, the flux is difficult to dissolve, the bead surface loses its smoothness, and defects such as undercuts are likely to occur. Become. Al 2 O 3 ; Al 2 O 3 also has a high melting point and is effective in adjusting the fluidity of molten slag and adjusting the appearance of the bead. This effect of Al 2 O 3 is important when using the method of the present invention for horizontal multilayer welding. If the basic component of the flux is only CaF 2 - CaO - MgO, the overlapping parts of the beads will not be smooth and will be uneven. However, the addition of Al 2 O 3 improves the compatibility of the beads with each other, resulting in a smooth multilayer bead surface. Such an effect of Al 2 O 3 cannot be obtained with less than 5wt.% of the total flux, and if it exceeds 35wt.%, slag tends to be caught in the weld metal, which deteriorates the X-ray performance, so it is preferable. do not have. SiO 2 ; SiO 2 is extremely effective in adjusting slag viscosity and improving bead appearance, but on the other hand,
SiO 2 is reduced in the arc atmosphere, increases Si and oxygen in the weld metal, and causes microcracks to occur. Therefore, considering the transfer of Si from the wire, it is necessary to limit the flux in the present invention to 8.0 wt.% or less with respect to the entire flux. In sintered flux, water glass is used as a fixing agent during granulation, but this contains a large amount of SiO 2 , and in normal fluxes, 3 to 4 wt.% SiO 2 is mixed. Therefore, in the flux of the present invention, the amount of SiO2 that can be added as a powder raw material is 4.0 wt.% or less. Si: The present invention aims to reduce Si in the weld metal as much as possible from the viewpoint of preventing microcracks, and substantially does not use Si as a deoxidizing agent. Most of the deoxidizing agent function is achieved by Al. Al: As mentioned above, Al is an essential component from the viewpoint of preventing microcracks, and by adding it from the flux as well as the wire, the Al content in the weld metal is stabilized. Further, addition of Al from flux is important for preventing gas defects such as blowholes and pockmarks, and such an effect is difficult to obtain by adding Al from wire alone.
The amount of Al added to the flux can be selected in relation to the Al content of the wire to be combined, but 0.5 to 7 wt.% is good, with 0.5 wt.% based on the entire flux.
If it is less than that, gas defects are likely to occur in the weld metal.
Moreover, if it exceeds 7wt.%, the bead appearance will be impaired, which is not preferable. The essential components of the flux in the present invention have been described above, but the additive raw materials for these components can be added in the form of single substances, compounds, ores, or molten fluxes containing the above components. That is, the raw materials used are as follows. CaF 2 ; Fluorite, molten flux, etc., CaO; Lime carbonate, wollastonite, molten flux, etc., MgO;
Magnesia clinker, spinel, fused flux, etc., Al 2 O 3 ; alumina, siyamoto, spinel, fused flux, etc. Al; metal Al, Fe-Al
etc. In addition, in the flux in the present invention,
Along with the above essential ingredients, CO2 equivalent amount is 0.5 to 4.0wt%
When carbonate minerals such as CaCO 3 and BaCO 3 are added in the range of 20 to 30%, they are effective in reducing the hydrogen partial pressure in the arc cavity and preventing micro blowholes caused by hydrogen. Other flux components that can be used include metal fluorides such as BaF 2 , MgF 2 and NaF, and metal oxides such as MnO and ZrO 2 that are used as ordinary welding raw materials. [Example] First, an alloy having the composition shown in Table 1 was produced in a vacuum melting furnace, and then forged, rolled and wire-drawn.
Wires of 2.4 mmφ or 3.2 mmφ were produced. however,
Regarding W-13, cracks occurred during forging during the wire manufacturing process, and it was not possible to finish it into wire. Among the wires shown in Table 1, W-1 to W-7 are wires used in the present invention, and W-8 to W-15 are wires used in comparative examples to clarify the effects of the present invention method. . Next, fluxes for submerged arc welding having the compositions shown in Table 2 were prepared. In this case, the raw materials used were molten flux powder and alumina cement powder in addition to ore powder, composite powder, or metal powder used as usual welding flux raw materials. All fluxes are sintered fluxes that are granulated using water glass as a fixing agent and fired at 500°C for 1 hr. Incidentally, among the fluxes in Table 2, F-1 to F-5 are fluxes used in the method of the present invention, and F-6 to F-10 are fluxes used in comparative examples. Using the above wire and flux,
Nineteen types of submerged arc welding were performed using the steel plates shown in Table 3 and the welding conditions shown in Table 4 and FIGS. 2 and 3. The welding length is 2m. Table 5 shows the combinations of flux, wire, steel plate, and welding conditions in the welding performed, and the results of the accuracy test of the welded part. To check the accuracy of the weld, first observe the appearance of the bead, then grind the excess bead to the plate surface (d 1 , d 2 , d 3 , d 4 in Fig. 3) and perform an X-ray transmission test as shown in Fig. 3. (according to JIS Z 3104), and then a penetrant test was conducted on the plate surface and the surface that had been shaved 2 mm further (Fig. 3 l 1 , l 2 , l 3 , l 4 ) to investigate the presence or absence of microcracks. . Table 5 shows the total number of cracks that occurred on the front and back sides of the welded area, expressed as the number of cracks that occurred per meter. After that, a tensile test piece g 1 (JIS Z 3111A2
No.) and impact test piece f 1 (JIS Z 2202 No. 4) were taken and subjected to the respective tests. The impact test
The welding was carried out at -196°C, which is required for LNG tank welds (9% Ni steel joints). The accuracy results for the above welds are shown in the right column of Table 5.
Among Examples, No. 1 to No. 7 were able to obtain excellent welds due to the effect of the present invention, but No. 8 to No. 19 were able to obtain excellent welds as shown in Table 5 for the individual reasons. , inappropriate Ni, Mo, Al, and Cr contents in the wire, as well as CaF 2 , CaO+MgO, and
Inappropriate SiO 2 , Al 2 O 3 and Al contents and the addition of Si to the flux caused problems such as poor bead appearance, occurrence of microcracks or solidification cracks, unsatisfactory mechanical properties, and poor X-ray evaluation results. [Effects of the present invention] As described above, the present invention prevents micro-cracks and solidification cracks from occurring during submerged arc welding of low-temperature Ni alloy steels such as 5.5Ni steel and 9Ni steel, and has excellent mechanical properties. The present invention provides a welding method that not only provides a welded part but also satisfies bead appearance and X-ray performance.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
第１図は９％Ni鋼の溶接部において、ミクロ
割れ発生傾向に及ぼすAl、Siの影響を説明する
ための図、第２図は本発明実施例において用いた
開先形状および積層要領を示す正面図、第３図は
本発明実施例において実施した溶接部の確性要領
を説明するための溶接部の正面図である。
Figure 1 is a diagram for explaining the influence of Al and Si on the tendency for micro-cracking to occur in a welded joint of 9% Ni steel. Figure 2 shows the groove shape and lamination procedure used in the embodiment of the present invention. FIG. 3 is a front view of a welded part for explaining the accuracy of the welded part carried out in the embodiment of the present invention.
Claims (1)
0.10〜2.0wt.％を含有し、かつ、Si；0.15wt.％以
下、Cr；5.0wt.％以下に限定した溶接ワイヤと、
CaF2；30〜70wt.％、CaO及び／又はMgO；８
〜30wt.％、Al2O3；５〜35wt.％、Al；0.5〜7wt.
％を含有し、かつ、SiO2；8wt.％以下に限定し、
Siを実質的に含有しない溶接フラツクスとを組み
合わせて行なう事を特徴とする低温用鋼のサブマ
ージアーク溶接法。1 Ni; 60-88wt.%, Mo; 10-38wt.%, Al;
A welding wire containing 0.10 to 2.0 wt.% and limited to Si; 0.15 wt.% or less, Cr; 5.0 wt.% or less;
CaF2 ; 30-70wt.%, CaO and/or MgO; 8
~30wt.%, Al2O3 ; 5 ~ 35wt.%, Al; 0.5~7wt.
%, and limited to less than 8 wt.% SiO 2 ,
A submerged arc welding method for low-temperature steel, characterized in that it is carried out in combination with a welding flux that does not substantially contain Si.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14219984A JPS6123596A (en) | 1984-07-11 | 1984-07-11 | Submerged arc welding process of steels for low temperature service |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14219984A JPS6123596A (en) | 1984-07-11 | 1984-07-11 | Submerged arc welding process of steels for low temperature service |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6123596A JPS6123596A (en) | 1986-02-01 |
| JPS6335355B2 true JPS6335355B2 (en) | 1988-07-14 |
Family
ID=15309692
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14219984A Granted JPS6123596A (en) | 1984-07-11 | 1984-07-11 | Submerged arc welding process of steels for low temperature service |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6123596A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2529843B2 (en) * | 1987-03-09 | 1996-09-04 | 新日本製鐵株式会社 | 9Cr-1Mo steel submerged arc welding method |
| JP5417098B2 (en) * | 2009-09-11 | 2014-02-12 | 日鐵住金溶接工業株式会社 | Submerged arc welding method for low temperature steel |
| CN105643067A (en) * | 2016-03-30 | 2016-06-08 | 武汉冶钢结构有限责任公司 | SMAW (shielded metal arc welding) process method for steel plates with 9% of Ni |
| US11161195B2 (en) * | 2018-03-27 | 2021-11-02 | Nippon Steel Corporation | Ni-based alloy wire for submerged arc welding and method of manufacturing welding joint |
-
1984
- 1984-07-11 JP JP14219984A patent/JPS6123596A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6123596A (en) | 1986-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH06328292A (en) | Submerged arc welding method for high-strength cr-mo steel | |
| KR20090012045A (en) | Weld metal and titania-based flux cored wire | |
| JP7179639B2 (en) | Sintered flux for submerged arc welding for high-strength steel | |
| JPH08164498A (en) | Coated arc welding rod for austenitic stainless steel | |
| JPS6335355B2 (en) | ||
| JP6437420B2 (en) | Firing flux for submerged arc welding of high strength steel | |
| JPH11291086A (en) | Submerged arc welding method for high cr ferritic heat resistant steel | |
| JP6401145B2 (en) | Submerged arc welding method for duplex stainless steel | |
| WO2022230615A1 (en) | Submerged arc welded joint | |
| JP2529843B2 (en) | 9Cr-1Mo steel submerged arc welding method | |
| JP2000102892A (en) | Firing type flux for submerge arc welding and its manufacture | |
| JPH0378197B2 (en) | ||
| JPH01258894A (en) | Submerged arc welding method for 9cr-1mo steel | |
| JP6908547B2 (en) | Bond flux for multi-electrode single-sided submerged arc welding | |
| JPH0371237B2 (en) | ||
| JPH07171695A (en) | Method for submerged arc welding of 960mpa high tensile steel | |
| JPH0829431B2 (en) | Low-hydrogen coated arc welding rod | |
| JPS60127095A (en) | Calcined flux | |
| JPH06328291A (en) | Bond flux for submerged arc welding | |
| JP2024112534A (en) | Low hydrogen type covered electrode | |
| JPS63199093A (en) | Arc welding electrode coated on stainless core wire | |
| JPH0242312B2 (en) | ||
| JPH09271982A (en) | Ni-cr group covered electrode | |
| JP2000334596A (en) | Production of calcined flux for submerged arc welding | |
| JP2024140424A (en) | Submerged arc welding method for high strength steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |