JPS5940556B2 - High toughness seamless wire for arc welding - Google Patents

Description

【発明の詳細な説明】 本発明はガスシールドアーク溶接並びに潜弧溶接に用い
るシームレスワイヤに係り、さらに詳しくは、特殊なボ
ロン源により、極めて微量のボロンを均一に含有せしめ
たガスシールドアーク溶接並びに潜弧溶接に用いるシー
ムレスワイヤに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seamless wire used in gas-shielded arc welding and submerged arc welding. This invention relates to seamless wire used in submerged arc welding.

先きに本発明のシームレスワイヤをガスシールドアーク
溶接用ワイヤとして説明する。First, the seamless wire of the present invention will be explained as a wire for gas shielded arc welding.

近年、鋼構造物の大型化にともない、構造物自身の重量
軽減のため使用鋼材は高張力鋼化する傾向にあり、かつ
能率向上をはかる意図から大入熱溶接法が採用されるす
う勢にある。In recent years, as steel structures have become larger, there has been a trend toward using high-strength steel to reduce the weight of the structures themselves, and high heat input welding methods are increasingly being adopted with the intention of improving efficiency. .

かかる情勢下にあつて高張力鋼溶接時の水素起因割れと
大入熱溶接時の切欠じん性低下問題は極めて重要視され
ることとなつた。これら問題に対処するため、先づ切欠
じん性に関しては最近ボロンやチタンの如き特殊元素を
溶接金属に添加することでほぼ満足な解答を得ている。Under these circumstances, hydrogen-induced cracking during welding of high-strength steel and the problem of reduced notch toughness during high-heat-input welding have become extremely important. To deal with these problems, a nearly satisfactory solution to the notch toughness has recently been obtained by adding special elements such as boron and titanium to the weld metal.

すなわち溶接金属中に１０〜７０ｐｐｍ程度のボロンを
微量含有させることにより溶接金属の焼入れ性を改善し
、大入熱溶接時の切欠じん性を大巾に改善しうる技術が
特公昭３９−１８３２２号、特公昭４３−１２２５８号
、特公昭４９一２０８６０号、特公昭４９−２４７７７
号、特公昭５０−６４２１号、特開昭５０−１１６３５
１号および英国特許第１０１８９００号および第１０７
６９０５号、米国特許第３７４５２９４号などにみられ
る如く既に提案されており、一部工業的利用にも成功し
ている。ここで、溶接金属にかかる微量のボロンを均一
、かつ適確に添加する技術が問題となる。Specifically, Japanese Patent Publication No. 39-18322 discloses a technique that improves the hardenability of weld metal by incorporating a small amount of boron of about 10 to 70 ppm into weld metal, and can greatly improve notch toughness during high heat input welding. , Special Publication No. 43-12258, Special Publication No. 49-20860, Special Publication No. 49-24777
No. 50-6421, JP 50-11635
1 and British Patent Nos. 1018900 and 107
6905, US Pat. No. 3,745,294, etc., and some of them have been successfully used industrially. The problem here is the technique for uniformly and accurately adding a small amount of boron to the weld metal.

この場合ガスシールド溶接法では一般に溶接用ワイヤか
ら微量ボロンを添加するのが普通となつている。ところ
で溶接ワイヤ形態のうち、先づソリッドワイヤ形態にお
ける微量ボロン添加時の問題点として、（１）１０〜７
０ｐｐｍの如き微量にボロン元素を、他の脱酸性元素お
よび合金元素と共存させ、溶解コントロールすることは
実際上、極めて困難である。In this case, in the gas shield welding method, it is common to add a small amount of boron to the welding wire. By the way, among the welding wire forms, first of all, the problems when adding trace amounts of boron in the solid wire form are (1) 10 to 7
In practice, it is extremely difficult to control the dissolution of a trace amount of boron, such as 0 ppm, coexisting with other deoxidizing elements and alloying elements.

（２）焼入性に富むボロン元素を含有した鋼塊を１ｍｍ
前後の細径に伸線することは、主として加工硬化現象に
より製綿過程で割れや破断を生じ易く実際上非常に困難
である。(2) 1mm steel ingot containing boron element with high hardenability
It is actually very difficult to draw the wire to a small diameter at the front and back because it tends to crack or break during the cotton-making process mainly due to the work-hardening phenomenon.

その他、ソリッドワイヤ自体の一般的な欠点として細径
ソリッドワイヤによる大電流溶接の際に生じ易い疲労強
度に関連するビード形状の劣化があり、かつスパッター
量の増加をも来たす傾向にある。In addition, general drawbacks of solid wire itself include deterioration of bead shape related to fatigue strength that tends to occur during high current welding with small diameter solid wire, and also tends to increase the amount of spatter.

しかもこの場合には、コールドシヤツトや梨の実割れな
どの内部欠陥をも残し易い。一方フラツクス入りワイヤ
技術は上述したソリツドワイヤに関する諸問題を解決す
るために開発されたものであるが、これとて従来技術に
は次の問題が残されている。Furthermore, in this case, internal defects such as cold shatter and pear cracking are likely to remain. On the other hand, although the flux-cored wire technology was developed to solve the problems related to the solid wire described above, the following problems remain in the prior art.

すなわち従来技術では、上記微量ボロン添加に粉状フエ
ロボロン（一般には２０％ボロン）を使用するのが普通
であるが、この場合、フエロアロイ中のボロン含量が高
いため充てんフラツクス中のＦｅ−Ｂ量を極度に低く抑
えざるを得ない結果、製線過程におけるかかる元素の偏
析が生じ易くこれが実用上の大きな難点となつていた。
これを解決する手段としてＢ２Ｏ３硼砂などの如きボロ
ンの非金属化合物を添加し、溶接時の還元作用によりメ
タルに微量ボロンを添加することも試みられているが、
これとて上記成分偏析問題は根本的に解決し得ず、かつ
還元反応条件によりボロン量が変動する心配がある。こ
の問題に対処するものとして本発明者らは既に特願昭５
０−１５８２６９にて提案した如く、新技術の工業化に
成功している。すなわち充てんフラツクス中のボロン量
偏析を防ぐため、０．５〜１０．０重量％のボロンを含
有するアトマイズド金属粉を作成し、これをフラツクス
入りワイヤに添加することにより所期の目的を達成した
。ところで、その後の溶接技術革新はめざましくかかる
フラツクス入りワイヤにおいても不満とする溶接施行法
が、次に記載するが如く要求されることとなつた。That is, in the conventional technology, powdered ferroboron (generally 20% boron) is usually used to add a small amount of boron, but in this case, the amount of Fe-B in the filling flux is reduced because the boron content in the ferroalloy is high. As a result of having to keep the content extremely low, segregation of such elements tends to occur during the wire making process, which has become a major practical difficulty.
As a means to solve this problem, attempts have been made to add a non-metallic compound of boron such as B2O3 borax, and add a small amount of boron to the metal through the reduction action during welding.
However, the problem of component segregation cannot be fundamentally solved, and there is a concern that the amount of boron may vary depending on the reduction reaction conditions. In order to deal with this problem, the present inventors have already filed a patent application in 1973.
As proposed in No. 0-158269, the new technology has been successfully industrialized. In other words, in order to prevent segregation of the amount of boron in the filling flux, an atomized metal powder containing 0.5 to 10.0% by weight of boron was created and added to the flux-cored wire to achieve the desired purpose. . Incidentally, subsequent welding technology innovations have been remarkable, and even for flux-cored wires, welding methods that are unsatisfactory have become required as described below.

すなわちかかる施工法において上記フラツクス入りワイ
ヤが問題とされる点は、（１）極めてデリケートなワイ
ヤ送給機構を有する機械溶接法において、ワイヤ表面に
外皮金属の合せ目を有する一般のフラツクス入りワイヤ
はワイヤ屈曲に対する方向性に起因される蛇行現象によ
り、ワイヤ送給トラブルを生じ易い。（２）フラツクス
入りワイヤに関する最大の難点として、ワイヤの吸湿の
問題がある。これは一般に銅めつきされないこの種のワ
イヤに生じ易いワイヤ表面の水分吸着、発錆現象、さら
にはワイヤ金属外皮合せ目から生ずる充填フラツクスの
吸湿現象である。かかる吸湿現象は溶接部の水素量増加
原因となり、特に合金元素を多くし一般に大きな焼入れ
性が付与されている高級鋼などで、しかも極厚鋼構造物
、高応力、重要部材の溶接施工において、溶接金属がボ
ロン添加により一段と焼入れ硬化される場合、水素起因
の割れやぜい化を来たし、かかる溶接構造物のぜい性破
壊につながる危険が大きいため是非解決しなければなら
ない重要な課題とされている。かかる水素起因溶接欠陥
の問題は、殊に構造物が低温度使用例えば北海寒冷地に
おける海洋構造物などの溶接施工となれば、溶接部の高
じん性化とともに極めて重要視されねばならない。もち
ろん、薄肉かつ焼入れ硬化度が比較的低い鋼種からなる
低応力構造物部材の溶接分野に対しては、かかる水素起
因割れやぜい化問題は可成り緩和して考え得るため、上
述した在来のフラツクス入りワイヤは経済的観点を加味
して工業的利用価値が大きいことは言及するまでもない
。本発明は特に溶接部ぜい性破壊の点で重要視しなけれ
ばならない部材の溶接施分野において、これら従来のフ
ラツクス入りワイヤが持つ欠点を一層根本的に改善し、
（１）ボロンのじん性向上効果を安定、かつ最大限に発
揮させること、（２）円滑なワイヤ送給性、（３）耐錆
性の向上および（４）すぐれた耐吸湿性を付与するため
、シームレスワイヤ化を行つたものである。In other words, the problems with the above-mentioned flux-cored wire in such a construction method are: (1) In a mechanical welding method that has an extremely delicate wire feeding mechanism, a general flux-cored wire with a seam of the outer metal on the wire surface cannot be used. Wire feeding troubles are likely to occur due to the meandering phenomenon caused by the directionality of wire bending. (2) The biggest problem with flux-cored wires is the problem of moisture absorption in the wires. This is due to moisture adsorption on the surface of the wire, which tends to occur in wires of this type that are not copper-plated, rusting, and moisture absorption by the filling flux that occurs at the seam of the wire metal shell. This moisture absorption phenomenon causes an increase in the amount of hydrogen in the weld zone, especially in high-grade steels that have a large amount of alloying elements and generally have high hardenability, and in welding of extremely thick steel structures, high stress, and important components. If the weld metal is further quenched and hardened by the addition of boron, hydrogen-induced cracking and brittleness will occur, and there is a great danger that this will lead to brittle failure of the welded structure, so this is an important issue that must be solved. ing. The problem of such hydrogen-induced welding defects must be considered extremely important, especially when welding is performed on structures that are used at low temperatures, such as offshore structures in the cold region of the North Sea, and the toughness of the welds is increased. Of course, in the field of welding low-stress structural members made of thin-walled steel with a relatively low degree of quench hardening, such hydrogen-induced cracking and embrittlement problems can be considered to be considerably alleviated, so the above-mentioned conventional Needless to say, the flux-cored wire has great industrial utility value from an economical point of view. The present invention further fundamentally improves the drawbacks of these conventional flux-cored wires, especially in the field of welding of parts where importance must be given to the brittle fracture of welded parts.
(1) To stably and maximize the toughness-improving effect of boron, (2) to provide smooth wire feeding, (3) to improve rust resistance, and (4) to provide excellent moisture absorption resistance. Therefore, it was made into a seamless wire.

すなわち、本発明は０．５超〜１０．０重量％のボロン
を含むアトマイズド金属粉を１．５〜３０．０重量％含
有することを必須としたフラツクスに固着剤を添加し、
粉粒状になしたるものを充填してなるガスシールド溶接
用高じん性シームレスワイヤである。以下本発明のシー
ムレスワイヤをガスシールドアーク溶接用として用いた
場合について詳細に説明する。That is, the present invention adds a fixing agent to a flux that essentially contains 1.5 to 30.0% by weight of atomized metal powder containing more than 0.5 to 10.0% by weight of boron,
This is a high toughness seamless wire for gas shield welding that is filled with granular material. The case where the seamless wire of the present invention is used for gas-shielded arc welding will be described in detail below.

まず、第１図はボロン源としてアトマイズド金属粉を使
用した本発明シームレスワイヤとフエロボロンの形態で
ボロンを添加した従来ワイヤによる溶着金属の衝撃値を
統計的に処理し、ばらつきの度合を標準偏差により比較
したものである。First, Figure 1 shows the statistical processing of the impact values of the weld metals of the seamless wire of the present invention using atomized metal powder as a boron source and the conventional wire to which boron is added in the form of ferroboron, and the degree of dispersion is expressed by the standard deviation. This is a comparison.

すなわち、微量ボロン源の種類と溶着金属の衝撃じん性
変動特性との関係を求める目的で、２．５重量％のボロ
ンを含むアトマイズド金属粉を２および６重量％および
２０重量％ボロンを含むフエロボロンを０．３重量％そ
れぞれ含有し、その他フエロマンガン１４重量％、フエ
ロシリコン１２重量％、蛍石１重量％、チタン酸カリ０
．５重量％および残部は鉄粉からなるフラツクスを３種
類配合し、ボロン含有アトマイズド金属粉を含む前２者
のフラツクスは珪酸カリをフラツクス全量に対し５重量
％添加、湿式かく拌後３５０℃にて乾燥、粉粒状になし
たるものをそれぞれ軟鋼を外皮とするシームレスおよび
一般の継目あり管状ワイヤに１３重量％充填した１，６
ｍｍ径のものを各１０００ｋｇ製造し実験に供した。テ
ストワイヤは２０ｋｇ毎に抜き取り５０ＨＴ鋼からなる
母材に対し溶接電流４５０Ａ１アーク電圧４０Ｖ１溶接
速度１５ｃｍ／Ｍｍ．ｓＣＯ２流量２０１／Ｍｉｎ頁溶
接入熱７２ｋＪ／Ｃｍ）なる大入熱の５パス溶接で溶着
金属を作成した。That is, for the purpose of determining the relationship between the type of trace boron source and the impact toughness fluctuation characteristics of the weld metal, atomized metal powder containing 2.5% by weight boron was mixed with ferroboron containing 2, 6% and 20% by weight boron. 0.3% by weight each, and 14% by weight of ferromanganese, 12% by weight of ferrosilicon, 1% by weight of fluorite, and 0% by weight of potassium titanate.
．． Three types of fluxes were blended: 5% by weight and the remainder was iron powder, and the first two fluxes containing boron-containing atomized metal powder were mixed with 5% by weight of potassium silicate based on the total flux, and heated at 350°C after wet stirring. 1,6, which was dried and made into powder, was filled at 13% by weight into seamless and general jointed tubular wires with a mild steel outer shell, respectively.
1000 kg of each sample with a diameter of mm was manufactured and used for experiments. Test wires were sampled every 20 kg and applied to a base material made of 50HT steel at a welding current of 450 A, arc voltage of 40 V, and welding speed of 15 cm/Mm. Weld metal was created by 5-pass welding with a high heat input of sCO2 flow rate of 201/Min page welding heat input of 72 kJ/Cm).

各試験体よりそれぞれ２本の試験片を採取し、いづれの
ワイヤについても１００回の繰返し衝撃試験を実施し、
Ｏ℃における衝撃値のばらつき度合を第１図に示した。Two test pieces were taken from each test piece, and each wire was subjected to a 100-times repeated impact test.
Figure 1 shows the degree of variation in impact values at 0°C.

これより、ボロンをアトマイズド金属粉の形態で添加し
たシームレスワイヤによる溶着金属の衝撃値は平均値が
高く、しかもそのばらつきは標準偏差σで見るとおり１
，０ｋ９−ＭｌＯ．７６ｋｇ−ｍの如く非常に小さいこ
とが判る。一方フエロボロンの形態でボロンを添加した
継目あり従来ワイヤの場合は衝撃値の平均こそ１８２ｋ
ｇ−ｍとボロンを添加しないこれまでのフラツクス入り
ワイヤに比べ高い値であつたが、標準偏差は２．７ｋｇ
−ｍと大きな値を示した。したがつて、従来技術により
ボロンを添加したワイヤではたとえ衝撃値が高い場合に
も、極端に低い値が得られることがあり、必ずしも安心
出来ないことが判つた。From this, it can be seen that the average value of the impact value of the welded metal by the seamless wire containing boron in the form of atomized metal powder is high, and the variation is 1 as seen by the standard deviation σ.
,0k9-MlO. It can be seen that the weight is very small, such as 76 kg-m. On the other hand, in the case of a conventional wire with seams containing boron in the form of ferroboron, the average impact value is 182k.
Although the g-m value was higher than that of conventional flux-cored wires that did not contain boron, the standard deviation was 2.7 kg.
It showed a large value of −m. Therefore, it has been found that even when the impact value is high, an extremely low value may be obtained with the wire to which boron is added according to the prior art, and it is not necessarily reliable.

この点本発明になる技術で作製したシームレスワイヤは
上述した如く、衝撃値が高く、かつばらつきも極めて小
さいので、大入熱溶接においても安心して実用出来るこ
とが判つた。更に、本発明者らはボロン源における最適
のボロン量を求める目的でボロン元素を種々の割合で含
有する鉄基のアトマイズド金属粉を作成し、ボロン量と
溶接金属の衝撃じん性との関係を求め第２図に結果例を
示した。In this regard, as mentioned above, the seamless wire produced by the technique of the present invention has a high impact value and extremely small variation, so it has been found that it can be put to practical use with confidence even in high heat input welding. Furthermore, in order to find the optimal amount of boron in the boron source, the present inventors created iron-based atomized metal powders containing boron elements in various proportions, and investigated the relationship between the amount of boron and the impact toughness of the weld metal. An example of the results is shown in Figure 2.

この実験ではフラツクス中のボロン含有アトマイズド金
属粉の比率を１３重量％一定とし、残部８７重量％は脱
酸性元素および鉄粉を必須成分とするフラツクスを軟鋼
外皮から成るシームレスワイヤに１３重量％添加し、１
．６能径のワイヤを製造し第１図同様溶接電流４５０Ａ
１アーク電圧４０、溶接速度１５？／ＭｉｎＳｃＯ２流
量２０１／Ｍｉｎの条件で溶着金属の衝撃試験片を作成
した。第２図の結果から金属粉中のボロン量が０．５重
量％近傍まで衝撃値は急激に向上し、０．５超〜１０．
０重量％まで高じん性は保持されるが、１０．０重量％
を超えると逆にじん性は大きく低下することが判る。In this experiment, the ratio of boron-containing atomized metal powder in the flux was kept constant at 13% by weight, and the remaining 87% by weight was made by adding 13% by weight of a flux containing deoxidizing elements and iron powder as essential components to a seamless wire made of a mild steel outer shell. ,1
．． A wire with a diameter of 6 was manufactured, and the welding current was 450 A as in Figure 1.
1 arc voltage 40, welding speed 15? /MinScO2 An impact test piece of the deposited metal was prepared under the condition of a flow rate of 201/Min. From the results shown in Figure 2, the impact value increases rapidly when the amount of boron in the metal powder approaches 0.5% by weight, and ranges from more than 0.5 to 10% by weight.
High toughness is maintained up to 0% by weight, but 10.0% by weight
It can be seen that, on the contrary, the toughness decreases significantly when the temperature exceeds .

これは０．５重量％未満ではボロンの添加効果が少なく
、０．５重量％超で始めてボロンによる鋼の焼入れ効果
が十分発揮されるため、溶接金属のミクロ組織が微細化
されたことによると考えられる。This is because the effect of boron addition is small when it is less than 0.5% by weight, and the effect of boron hardening the steel is fully exerted only when it exceeds 0.5% by weight, so the microstructure of the weld metal is refined. Conceivable.

しかし１０．０重量％を超えるとボロンによる焼入れ効
果が大きくなりすぎるため、鋼が著しく硬化し、かえつ
て衝撃じん性を劣化させたものと考えられる。また、梨
の実状高温割れの観点からも１０．０重量％を超えた添
加は好ましくないことも判つた。したがつて本発明ワイ
ヤに添加する鉄基アトマイズド金属粉中のボロンは０，
５〜１０．０重量％の範囲に限定することが溶接金属の
衝撃じん性および高温割れ感受性の面から好ましいこと
が判つた。なお、従来の技術と同様にボロン単独添加よ
りＴｉまたはＴｉＯ２との複合添加において、ボロンの
添加効果がより有効に発揮されることは第２図の結果に
も示す如く論するまでもない。However, if the content exceeds 10.0% by weight, the hardening effect of boron becomes too large, which causes the steel to become extremely hardened, which is thought to actually deteriorate the impact toughness. It was also found that addition of more than 10.0% by weight is not preferable from the viewpoint of hot cracking of pear fruits. Therefore, the amount of boron in the iron-based atomized metal powder added to the wire of the present invention is 0,
It has been found that it is preferable to limit the content to a range of 5 to 10.0% by weight in terms of the impact toughness and hot cracking susceptibility of the weld metal. It goes without saying that, as shown in the results of FIG. 2, the effect of boron addition is more effectively exhibited when combined with Ti or TiO2 than when boron is added alone, as in the prior art.

次いで本発明者らはシームレスワイヤに対するボロン含
有鉄基アトマイズド金属粉の有効添加範囲を検討し、第
３図の結果を得た。Next, the present inventors investigated the effective range of addition of the boron-containing iron-based atomized metal powder to the seamless wire, and obtained the results shown in FIG. 3.

この実５験では鉄基アトマイズド金属粉中のボロン含量
を４重量％、フラツクス充てん率は１６重量％一定とし
、その他の条件は第１図および第２図の条件と同一条件
で実施した。In these five experiments, the boron content in the iron-based atomized metal powder was kept constant at 4% by weight, the flux filling rate was constant at 16% by weight, and the other conditions were the same as those shown in FIGS. 1 and 2.

第３図に示す実験結果からボロンを含有したアトマイズ
ド金属粉のフラツクス中への添加量は１．５〜３０重量
％の範囲で衝撃じん性改善に効果のあることが判る。The experimental results shown in FIG. 3 show that the amount of boron-containing atomized metal powder added to the flux in the range of 1.5 to 30% by weight is effective in improving impact toughness.

１．５重量％未満ではボロンの添加効果が少なく、３０
重量％を超えると鋼がボロンの焼入れ硬化性により硬く
なりすぎたためじん性が低下したものである。If it is less than 1.5% by weight, the effect of adding boron is small, and 30
If it exceeds % by weight, the steel becomes too hard due to the quench hardening properties of boron, resulting in a decrease in toughness.

この実験に於てもボロンはＴｉ若しくはＴｉＯ２との複
合添加においてより有効であることが確認された。しか
し、いずれも従来のものより高いじん性が得られている
。またボロンをアトマイズド金属粉の形態で添加する理
由は衝撃値を高位安定さす既述の効果の他にワイヤ製造
工程におけるフラツクス充てん作業を容易にするという
大きな特徴があることによるものである。すなわち、ア
トマイズド金属粉は通常の溶接用フラツタス原料として
用いる金属粉と違いほぼ完全な球状を呈するため、ワイ
ヤ減径工程中におけるフラツクスの流動性を改善する。
さらに、本発明においては、上記アトマイズド金属粉を
上記範囲に配合したフラツクスに、例えばＮａ２ｓｉＯ
！やＫ２ＳｌＯ３その他の無機固着剤、またはデキスト
リン、アルギン酸ソーダ、その他の有機固着剤を単独ま
たは複合して添加しこれらを混合した後乾燥して粉粒状
とすることにより微量添加物、例えば金属粉などの偏析
防止をはかり、かつ充填フラツクスの粒度を整えること
により、原料フラツクスのシームレスパイプへの充填を
容易にするものである。なお、これら固着剤の添加量は
フラツクス全量に対し１〜１０重量％程度が有効である
。すなわちかかる本発明の技術により１．２ｍｍ径のワ
イヤは勿論、これまでフラツクス入りワイヤ製造技術で
は困難とされてきた０．８ｍｍ径の如き細径ワイヤの製
造もワイヤ外皮合せ目が存在しないシームレスワイヤ技
術を利用することにより可能となつた。In this experiment as well, it was confirmed that boron is more effective when added in combination with Ti or TiO2. However, both have higher toughness than conventional ones. The reason why boron is added in the form of atomized metal powder is that in addition to the aforementioned effect of stabilizing the impact value at a high level, it also has the great feature of facilitating the flux filling operation in the wire manufacturing process. That is, since the atomized metal powder exhibits a nearly perfect spherical shape unlike the metal powder used as a flatus raw material for normal welding, it improves the fluidity of the flux during the wire diameter reduction process.
Furthermore, in the present invention, for example, Na2siO
! , K2SlO3 and other inorganic fixing agents, or dextrin, sodium alginate, and other organic fixing agents are added singly or in combination, mixed, and then dried to form powder to form trace additives such as metal powder. By preventing segregation and adjusting the particle size of the filling flux, it is possible to easily fill the seamless pipe with the raw material flux. It is effective to add these fixing agents in an amount of about 1 to 10% by weight based on the total amount of flux. In other words, with the technology of the present invention, not only can wires with a diameter of 1.2 mm be manufactured, but also wires with a diameter as small as 0.8 mm, which has been considered difficult with flux-cored wire manufacturing techniques, can be manufactured, as well as seamless wires in which there is no wire sheath seam. This was made possible through the use of technology.

ところでボロン含有アトマイズド金属粉の粒度範囲は、
３５０メツシユ以下の微粉は全体の６０重量％以下にお
さえることが望ましい。By the way, the particle size range of boron-containing atomized metal powder is
It is desirable that the amount of fine powder of 350 mesh or less is 60% by weight or less of the total weight.

すなわち６０重量％を超えると、アーク中においてボロ
ンが燃焼され易くなり、ボロンの歩留が低下するので好
ましくない。さらに、粒度の上限はフラツクスの充てん
に支障を来たさない最大粒径を選んで差支えない。That is, if it exceeds 60% by weight, boron is likely to be burned in the arc and the yield of boron will decrease, which is not preferable. Further, the upper limit of the particle size may be selected from the maximum particle size that does not interfere with flux filling.

なお、本発明に用いるボロン含有アトマイズド金属粉に
更に必要に応じて従来から溶接金属の性能を改善する目
的で使用されているＮｉ，Ｃｒ，ＭＯなどの元素を単独
もしくは複合添加し溶接金属の引張特性、衝撃特性およ
び耐割れ性などの諸性能を改善することもできる。同様
にして、この金属粉にはボロン元素と同時に適当量のＴ
ｉ，Ｚｒ，Ａｌなどの脱酸性元素も添加できることは言
及するまでもない。また、本発明になるシームレスワイ
ヤは上記アトマイズド金属粉を上記範囲にて配合したフ
ラツクスを８〜３６重量％の範囲で充填することが有効
である。In addition, if necessary, elements such as Ni, Cr, and MO, which have been conventionally used for improving the performance of weld metal, may be added singly or in combination to the boron-containing atomized metal powder used in the present invention to improve the tensile strength of the weld metal. Properties such as properties, impact properties and cracking resistance can also be improved. Similarly, this metal powder contains an appropriate amount of T at the same time as boron element.
It goes without saying that deoxidizing elements such as i, Zr, and Al can also be added. Further, it is effective to fill the seamless wire according to the present invention with a flux containing the atomized metal powder in the range of 8 to 36% by weight.

８重量％未満では脱酸性元素およびボロン添加量を上記
範囲内で操作しても、溶接金属の脱酸性元素およびボロ
ン量が不足するので大入熱溶接において高い衝撃じん性
を確保することは困難である。If it is less than 8% by weight, even if the amount of deoxidizing element and boron added is controlled within the above range, the amount of deoxidizing element and boron in the weld metal will be insufficient, making it difficult to ensure high impact toughness in high heat input welding. It is.

逆に３６重量％を超えると、充填フラツクスのワイヤ断
面積に占める割合が大きくなりすぎるため、充填フラツ
クスの溶融が均一でなくなるとともにボロン含有範囲下
限のアトマイズド金属粉を使用したとしても溶接金属中
のボロン量が不当に多くなり、じん性が損われるため好
ましくない。したがつて、本発明になるシームレスワイ
ヤのフラツクス充填率は８〜３６重量％を適当とする。
また本発明によるシームレスワイヤは上記ボロン含有ア
トマイズド金属粉を必須成分とするが、その他の脱酸性
元素、鉄粉、スラグ生成剤ガス生成剤、アーク安定剤な
ど溶接材料に対し一般に使用されているフラツクス剤を
添加し、溶接金属の清浄化とビード形状の改善をはかれ
ることは論するまでもない。On the other hand, if it exceeds 36% by weight, the proportion of the filling flux in the cross-sectional area of the wire becomes too large, resulting in uneven melting of the filling flux and even if atomized metal powder with a lower boron content range is used, the content of the weld metal will increase. This is not preferable because the amount of boron increases unduly and the toughness is impaired. Therefore, the flux filling rate of the seamless wire according to the present invention is suitably 8 to 36% by weight.
Furthermore, the seamless wire according to the present invention contains the boron-containing atomized metal powder as an essential component, but it also contains other deoxidizing elements, iron powder, slag forming agents, gas generating agents, arc stabilizers, and other fluxes commonly used in welding materials. It goes without saying that additives can be added to clean the weld metal and improve the bead shape.

本発明ワイヤの外皮材質として極軟鋼を普通とするが、
必要に応じてＮｉ，Ｃｒ，ＭＯその他微量合金元素をワ
イヤ外皮から添加するため、低合金鋼をも採用できる。Although the outer sheath material of the wire of the present invention is usually extremely mild steel,
Since trace amounts of alloying elements such as Ni, Cr, MO, and others are added from the wire sheath as necessary, low-alloy steel can also be used.

さらにシームレスワイヤ技術を活用した本発明ワイヤの
大きな効果は一般のフラツクス入りワイヤに比べ、ワイ
ヤ中の水分を最低限に抑え、かつ保管中および使用中の
ワイヤ吸湿現象をほとんど皆無にすることができ、よつ
て溶接金属の拡散性水素量を０．５ｍ１／１００ｇｒ．
以下にすることが可能である。Furthermore, the wire of the present invention, which utilizes seamless wire technology, has the great effect of minimizing moisture content in the wire compared to general flux-cored wire, and virtually eliminating moisture absorption during storage and use. Therefore, the amount of diffusible hydrogen in the weld metal is set to 0.5 m1/100 gr.
It is possible to do the following.

この事実はアトマイズドボロンの形でボロンを添加した
ことによりボロンの偏析を殆んど皆無としたワイヤにお
いては溶接金属の焼入性の管理が容易であるばかりでな
く、該焼入性が向上される傾向にある高じん性鋼溶接時
の水素起因による低温割れやぜい化を防止するのに極め
て有効であることを意味するものである。ところで本発
明ワイヤ製造過程において、ワイヤから水素源を除去す
る操作としては先ず既述した方法で粉粒状化したフラツ
クスを添加した金属粉が酸化しない最高温度たとえば３
５０℃〜５５０℃の範囲に高温乾燥しフラツクス中の水
分や有機分を高温分解させる。またその他の方法として
は比較的低温度にて乾燥した粉粒状フラツクスをシーム
レス管に充填した後、製線過程においてこれを７００℃
前後に焼鈍することにより、伸線硬化したワイヤを軟化
すると同時に水素源を完全に除去することができる。さ
らに本発明ワイヤは上述した如く大気中にばく露過程に
おいて、ほとんど吸湿を皆無にし得ることは、同丁成分
組成のフラツクスを充填した外皮金属に合せ目のあるフ
ラツクス入りワイヤとの吸湿試験結果を比較した第４図
において明らかである。This fact shows that in wires with almost no boron segregation due to the addition of boron in the form of atomized boron, it is not only easy to control the hardenability of the weld metal, but also the hardenability is improved. This means that it is extremely effective in preventing low-temperature cracking and embrittlement caused by hydrogen during welding of high toughness steels, which tend to occur. By the way, in the wire manufacturing process of the present invention, the hydrogen source is removed from the wire at the highest temperature at which the flux-added metal powder, which has been pulverized by the method described above, will not oxidize, for example, 3.
The flux is dried at a high temperature in the range of 50°C to 550°C to decompose moisture and organic components in the flux. Another method is to fill a seamless tube with granular flux dried at a relatively low temperature, and then heat it to 700°C during the wire making process.
By annealing before and after, the drawn hardened wire can be softened and at the same time the hydrogen source can be completely removed. Furthermore, as mentioned above, the wire of the present invention can absorb almost no moisture during the process of exposure to the atmosphere, as shown in the moisture absorption test results with a flux-cored wire with a seam in the outer metal coated with flux of the same composition. This is clearly seen in FIG. 4 for comparison.

すなわち第４図は上記要領で粉粒状に作成した本発明に
係る組成のフラツクスをワイヤ重量に対して１５重量％
あて充填した本発明の銅めつきしたシームレスワイヤ（
１．６ｍ１Ｌ径、記号Ａ）と外皮金属に合せ目があるフ
ラツクス入りワイヤ（１．６關径、記号Ｂ）を気温２０
〜２９℃、相対湿度７５〜９０％の大気中に裸状態で放
置し、経過日数毎に溶接金属の拡散性水素をＪＩＳＺ３
ｌｌ３により求めたものである。That is, FIG. 4 shows that the flux of the composition according to the present invention prepared in the form of powder as described above is 15% by weight based on the weight of the wire.
The copper-plated seamless wire of the present invention (
A flux-cored wire (1.6 mm diameter, symbol B) with a seam between the 1.6 m1L diameter, symbol A) and the outer sheath metal is heated to a temperature of 20°C.
The weld metal is left exposed in the atmosphere at ~29°C and a relative humidity of 75 to 90%, and the diffusible hydrogen in the weld metal is determined by JIS Z3 for each number of days that have passed.
It was determined by ll3.

この際の溶接条件は電流３００Ａ，ＤＣ…；電圧３２Ｖ
；速度３０α／Ｍｉｎ；ＣＯ２流量、２０！／Ｍｉｎで
あつた。The welding conditions at this time are current 300A, DC...; voltage 32V
; Speed 30α/Min; CO2 flow rate, 20! /Min.

図から明らかな如く、銅めつきできない従来ワイヤの水
素量は放置日数、経過とともに増加傾向を示しているが
、一方本発明ワイヤは４０日間放置しても水素量にほと
んど変化なく約０．３ｍ１／１００ｇｒ．溶着金属を呈
しており、上述したとおり水素起因の溶接欠陥を生じ難
いことが判る。As is clear from the figure, the amount of hydrogen in the conventional wire, which cannot be copper-plated, shows an increasing tendency with the number of days it is left and the passage of time, but on the other hand, the amount of hydrogen in the wire of the present invention shows almost no change even after being left for 40 days, about 0.3 m1 /100gr. It exhibits a welded metal, and as mentioned above, it can be seen that welding defects due to hydrogen are unlikely to occur.

このことは水素試験と同時に同一溶接条件で行なつたＪ
ＩＳＺ３ｌ５７規定の２５ｍｍ厚ＳＭ−５０Ｂ鋼から成
るＵ形溶接割れ試験結果を示す第５図において明白であ
る。すなわち従来ワイヤは放置日数５日目頃から断面割
れを発生し始めるのに対し、本発明ワイヤは４０日経過
しても割れは全く発生していない。また、第４図および
第５図においてワイヤの発錆状況を見ると、シームレス
ワイヤ技術を利用した本発明ワイヤは４０日経過しても
全く錆発生が認められないのに対し、従来ワイヤは１５
日位から錆を生じ、２０日目頃から溶接ビードに気孔を
形成する傾向にあることが判る。This was confirmed by J
This is evident in Figure 5, which shows the results of a U-shaped weld cracking test on 25 mm thick SM-50B steel according to ISZ3l57. That is, while the conventional wire starts to develop cross-sectional cracks after about 5 days of storage, the wire of the present invention shows no cracks at all even after 40 days. Furthermore, when looking at the state of rust on the wire in Figures 4 and 5, the wire of the present invention using seamless wire technology shows no rust at all even after 40 days, whereas the conventional wire
It can be seen that rust begins to form from the 20th day onward, and pores tend to form in the weld bead from around the 20th day.

以上記載した如く、本発明ワイヤは従来のシームレスワ
イヤ技術を効果的に利用することにより、焼入硬化性が
大きく、溶接割れの危険性が高いボロン添加高じん性溶
接を可能にしている。As described above, by effectively utilizing the conventional seamless wire technology, the wire of the present invention has high quench hardenability and enables boron-added high toughness welding, which has a high risk of weld cracking.

次に本発明のシームレスワイヤを潜弧溶接用として使用
する場合について、一部前述の項と重複するが、詳細に
説明する。Next, the case where the seamless wire of the present invention is used for submerged arc welding will be described in detail, although some of it overlaps with the above section.

従来の潜弧溶接に関するＢ元素利用例は非常に多いがこ
の場合にはフラツクスにＢを添加する例がほとんどであ
る。There are many examples of the use of B element in conventional submerged arc welding, but in most cases B is added to the flux.

ところが、Ｂを潜弧溶接用フラツクスに添加することは
、溶接条件によつてＢの歩留まりが左右されるため、微
量Ｂのコントロールは極めて困難となる欠点がある。す
なわち、潜弧溶接施工においては、他の施工法と同様、
開先初層の溶接では満足な溶け込みを得るためアーク電
圧を低目に設定し、最終仕上げ溶接はビード面を平滑に
仕上げる必用性から、アーク電圧を高目とするのが普通
である。かかる、電圧の変化はフラツクス消費量を左右
するため、結果として溶接金属中へのＢ添加量は一定し
ないきらいがある。同様にして、溶接電流によつてもＢ
量は影響される。したがつてフラツクスからＢの如き微
量元素を添加することは常に安定した衝撃じん性を求め
る上から細心の注意を要する。さらにフラツクスが吸湿
した場合にはアーク雰囲気が酸化性となるため、合金形
態で添加したＢ元素は、酸化消耗され所要の歩留まりが
得られない。したがつて実際施工においてフラツクスの
保管、管理に多大の注意を払わねばならない不便がある
。この点Ｂ元素をワイヤに添加すれば上記フラツクスに
よる場合の問題は解消できる利点がある。他方、フラツ
クス入りワイヤ技術については、既に特公昭５０−６４
２１号公報において、硬化性元素であるＢを溶接ワイヤ
に添加する技術が提案されている。However, adding B to flux for submerged arc welding has the disadvantage that it is extremely difficult to control the trace amount of B, since the yield of B is affected by welding conditions. In other words, in submerged arc welding construction, as with other construction methods,
When welding the first layer of a groove, the arc voltage is usually set low to obtain satisfactory penetration, and during final welding, the arc voltage is usually set high because it is necessary to finish the bead surface smoothly. Such changes in voltage affect the amount of flux consumed, and as a result, the amount of B added to the weld metal tends to be inconsistent. Similarly, depending on the welding current, B
Quantity is affected. Therefore, adding a trace element such as B to the flux requires careful attention in order to always obtain stable impact toughness. Further, when the flux absorbs moisture, the arc atmosphere becomes oxidizing, and the B element added in the form of an alloy is consumed by oxidation, making it impossible to obtain the required yield. Therefore, there is the inconvenience that great care must be taken in storing and managing the flux during actual construction. In this respect, if element B is added to the wire, there is an advantage that the problem caused by the above-mentioned flux can be solved. On the other hand, flux-cored wire technology was already developed in
In Japanese Patent No. 21, a technique is proposed in which B, which is a hardening element, is added to a welding wire.

しかし、公知文献にて採用されているフラツクス入りワ
イヤはいずれもワイヤ外皮に合せ目を有する形態のもの
が多くかかるワイヤにおいては周知の如く、ワイヤ保管
中、充てんフラツクスの吸湿とワイヤ面への水分吸着に
より、溶接金属の拡散性水素は増加傾向にある。したが
つてこの形態のフラツクス入りワイヤ技術では特に高じ
ん性にした高張力鋼などの低合金鋼浩接において、水素
起因の低温割れやぜい化を生じ易い。さらに、ワイヤ外
皮に合せ目のある非対象構造においてはワイヤ屈曲に方
向性を呈し、ソリツドワイヤにくらベワイヤ送給性に劣
り、しかも銅メツキを施せないことから給電性にも劣る
欠点がある。本発明は従来技術のかかる問題点を全て解
決し、潜弧溶接にも適用し、水素起因の諸欠陥を起し難
い送給性にすぐれた、潜弧溶接用高じん性シームレスワ
イヤを提供することにある。以下、本発明のシームレス
ワイヤを潜弧溶接に使用する場合について詳細に説明す
る。However, most of the flux-cored wires employed in the known literature have seams in the wire sheath, and as is well known, during wire storage, the filling flux absorbs moisture and the wire surface absorbs moisture. Diffusible hydrogen in weld metal tends to increase due to adsorption. Therefore, with this type of flux-cored wire technology, hydrogen-induced low-temperature cracking and embrittlement are likely to occur, particularly when welding low-alloy steel such as high-strength steel with high toughness. Furthermore, in an asymmetrical structure in which the wire sheath has a seam, the wire bends in a directional manner, and is inferior to a solid wire in terms of wire feedability.Moreover, since copper plating cannot be applied, there is a disadvantage in that the wire feedability is also poor. The present invention solves all of the problems of the prior art, and provides a highly tough seamless wire for submerged arc welding that is applicable to submerged arc welding and is resistant to hydrogen-induced defects and has excellent feedability. There is a particular thing. Hereinafter, the case where the seamless wire of the present invention is used for submerged arc welding will be described in detail.

本発明ワイヤには前述の如くアトマイズド金属粉からＢ
を添加するが、これは従来のＦｅ−ＢによるＢ添加方法
の欠点を解消するためである。As mentioned above, the wire of the present invention is made from atomized metal powder.
This is to overcome the drawbacks of the conventional method of adding B using Fe-B.

すなわち、アトマイズドされたＢ含有金属粉とは、均一
に溶解されたＢ含有金属粉をガスもしくは水により粉粒
状にした後、凝固させたもので、粒度による成分偏析が
全くないことはもちろん、適度の大きさとなつたアトマ
イズド金属粉は、製造過程においてその強い表面張力の
働きにより、ほぼ球状となるため、風化、酸化し難い利
点があること、さらに、この球状のＢ含有アトマイズド
金属粉は、固着剤添加によりフラツクスを粉粒状にする
際、フラツクス粒の核となり、充填フラツクスを理想的
な球状に造粒仕上げ易くなるという利点もある。次に、
Ｂをアトマイズド金属粉の形態で添加した場合の利点お
よび添加量を本発明の如く規定した理由を具体的に説明
する。まず、Ｂ源としてアトマイズド金属粉を使用した
本発明になる潜弧溶接用シームレスワイヤとＦｅ−Ｂの
形態でＢを添加したワイヤによる溶接金属の衝撃値を統
計的に処理し、ばらつきの度合を標準偏差により比較し
てみると、微量Ｂ源の種類と溶着金属の衝撃じん性の変
動特性の関係を求める目的で、３重量％のＢを含むアト
マイズド金属粉を２および５重量％および２０重量０Ｉ
）Ｂを含むＦｅ−Ｂを０．５重量％、それぞれ含有し、
その他Ｆｅ−Ｍｍｌ３重量％、Ｆｅ−ＳｉｌＯ重量％お
よび残部は鉄粉から成るフラツクスにフラツクス全量に
対し５重量％の水ガラスを添加混合、粉粒状になしたる
後、これらを１５重量％当てシームレス金属管に充填し
、６．４φワイヤをそれぞれ１０００ｋｇ製造した。In other words, atomized B-containing metal powder is made by pulverizing uniformly dissolved B-containing metal powder with gas or water and then coagulating it. The atomized metal powder, which has a size of When the flux is made into powder by adding the agent, it becomes the core of the flux granules, and has the advantage that it becomes easier to finish granulating the filled flux into an ideal spherical shape. next,
The advantages of adding B in the form of atomized metal powder and the reason why the amount added is specified as in the present invention will be explained in detail. First, we statistically processed the impact values of weld metals using a seamless wire for submerged arc welding according to the present invention using atomized metal powder as a B source and a wire to which B was added in the form of Fe-B, and evaluated the degree of variation. Comparing the standard deviations, for the purpose of determining the relationship between the type of trace B source and the variation characteristics of the impact toughness of deposited metal, atomized metal powder containing 3 wt% B was used at 2, 5 wt% and 20 wt%. 0I
) Each contains 0.5% by weight of Fe-B including B,
Others: 3% by weight of Fe-Mml, 3% by weight of Fe-SilO, and the rest is iron powder. Add and mix 5% by weight of water glass based on the total amount of the flux. After grinding into powder, apply 15% by weight of these to create a seamless Each metal tube was filled with 6.4φ wire weighing 1000 kg.

この中から２０ｋｇ毎にサンプルワイヤを抜き取り上記
実験に供した。この際の母材はＸ開先に機械加工した３
５ｍ７ｆｔ厚の５０ＨＴ鋼板とした。Sample wires were extracted from this sample every 20 kg and used in the above experiment. In this case, the base material was machined into an X groove.
A 50HT steel plate with a thickness of 5 m and 7 ft was used.

フラツクスは鉄粉−ＭｇＯ−Ａ２２Ｏ３系焼成形とし、
潜弧溶接は１２００Ａ，４０Ｖ，２３？／Ｍｉｎなる条
件により表裏１層盛りとした。各試験体よりそれぞれ２
本の試験片を採取し、いずれの試作シームレスワイヤに
ついても１００回の繰返し衝撃試験を実施し−３０℃に
おける衝撃値のばらつき度合を第１図に求めた。The flux is iron powder-MgO-A22O3 based sintered molding.
Is submerged arc welding 1200A, 40V, 23? /Min, one layer was formed on the front and back sides. 2 each from each test specimen
A test piece was taken, and the impact test was repeated 100 times for each of the prototype seamless wires, and the degree of variation in impact values at -30°C was determined as shown in Figure 1.

これにより、Ｂをアトマイズド金属粉の形態で添加した
シームレスワイヤによる溶接金属の衝撃値は平均値が高
く、しかもそのばらつきは標準偏差で見るとおり１．２
ｋｇ−Ｍ，Ｏ．９ｋ９−ｍの如く非常に小さかつた。一
方、Ｆｅ−Ｂの形態でＢを添加したシームレスワイヤの
場合は衝撃値の平均こそ８．１ｋｇ−ｍとＢを添加しな
いワイヤにくらべ高い値いを示したが、標準偏差が３．
１ｋｇ−ｍと大きな値となつた。As a result, the average value of the impact value of the weld metal produced by the seamless wire containing B added in the form of atomized metal powder is high, and the variation is 1.2 as seen in the standard deviation.
kg-M, O. It was very small, like 9k9-m. On the other hand, in the case of the seamless wire doped with B in the form of Fe-B, the average impact value was 8.1 kg-m, which is higher than the wire without B added, but the standard deviation was 3.1 kg-m.
The value was as large as 1 kg-m.

そこで本発明者らはＢ元素を種々の割合で含有する鉄基
のアトマイズド金属粉を作成し、最適のＢ量を求める目
的で金属粉中のＢ量と溶接金属の衝撃じん性の関係を求
めた。この実験ではフラツクス中のＢ含有アトマイズド
金属粉の比率を１０重量％一定とし、残部９０重量％は
脱酸性元素スラグ生成剤およびガス発生剤を必須とする
フラツクスを造粒充填し、表裏１パス溶接により溶接金
属の衝撃試１験片を作成した。この結果から金属粉中の
Ｂ量が０．５重量％近傍まで衝撃値は急激に向上し、０
．５超〜１０．０重量％の範囲で高じん性は保持される
が、１０．０重量％を超えると逆にじん性は大きく低下
することが判つた。Therefore, the present inventors created iron-based atomized metal powder containing the B element in various proportions, and determined the relationship between the B content in the metal powder and the impact toughness of the weld metal in order to find the optimal B content. Ta. In this experiment, the ratio of B-containing atomized metal powder in the flux was kept constant at 10% by weight, and the remaining 90% by weight was granulated and filled with a flux that required a deoxidizing element slag forming agent and a gas generating agent, and the front and back sides were welded in one pass. A weld metal impact test specimen was prepared. From this result, the impact value increases rapidly when the amount of B in the metal powder approaches 0.5% by weight, and
．． It was found that high toughness is maintained in the range of more than 5 to 10.0% by weight, but on the contrary, the toughness decreases significantly when it exceeds 10.0% by weight.

これは、０．５重量％以下ではＢの添加効果が少なく、
０，５重量％を超えて初めてＢによる鋼の焼入れ効果が
十分発揮されるため、溶接金属のミク口組織が微細化さ
れたことによると考えられる。This is because the effect of adding B is small below 0.5% by weight.
This is thought to be due to the fact that the hardening effect of B on steel is fully exhibited only when B exceeds 0.5% by weight, so that the microstructure of the weld metal is refined.

しかし、１０．０重量％を超えるとＢによる焼入れ効果
が大きくなりすぎるため、鋼が著しく硬化し、かえつて
衝撃じん性を劣化させたものと考えられる。また、梨実
状高温割れを発生し易くなることからも１０．０重量％
を超えた添加は好ましくないことが判つた。従つて、鉄
基アトマイズド金属粉中のＢは０．５超〜１０．０重量
％の範囲に限定することが溶接金属の衝撃じん性および
高温割れ感受性の面から好ましいことが判つた。However, if it exceeds 10.0% by weight, the quenching effect of B becomes too large, so that the steel is significantly hardened, and it is thought that this actually deteriorates the impact toughness. In addition, since pear-like hot cracking is likely to occur, 10.0% by weight is recommended.
It has been found that addition exceeding this amount is not preferable. Therefore, it has been found that it is preferable to limit B in the iron-based atomized metal powder to a range of more than 0.5 to 10.0% by weight from the viewpoint of the impact toughness and hot cracking susceptibility of the weld metal.

なお、従来公知の技術と同様にＢ単独添加よりＴｉおよ
び、またはＴｉＯ２との複合添加においてＢの添加効果
がより有効に発揮された。As with conventionally known techniques, the effect of B addition was more effectively exhibited when combined with Ti and/or TiO2 than when B was added alone.

ところで、本発明におけるＢ含有アトマイズド金属粉の
粒度範囲は３５０メツシユ以下の微粉は全体の６０重量
％以下に抑えることが望ましい。By the way, in the particle size range of the B-containing atomized metal powder in the present invention, it is desirable to suppress the fine powder of 350 mesh or less to 60% by weight or less of the total.

すなわち、６０重量％を超えるとＢが燃焼され易くなり
、Ｂの歩留りが低下するので好ましくない。さらに、粒
度の上限はフラツクスを粉粒状になした後のフラツクス
充填に支障をきたさない最大粒度を選べば良いが、本発
明者らの実験によると、２０メツシユを上限とするのが
良い。これ以上粗粒にすると他のフラツクス材と比重分
離し易くなり成分偏析の恐れが大きくなることと、１．
６關径の如き細径ワイヤの製造が困難となる。なお、本
発明に用いるＢ含有アトマイズド金属粉に、さらに必要
に応じて従来から溶接金属の性能を改善する目的で使用
されているＮｉ，Ｃｒ，ＭＯなどの元素を単独若しくは
複合添加し、溶接金属の引張特性、衝撃特性および割れ
特性などの諸特性を改善することもできる。That is, if the content exceeds 60% by weight, B is likely to be burned and the yield of B will decrease, which is not preferable. Furthermore, the upper limit of the particle size may be selected from the maximum particle size that does not interfere with the filling of the flux after it has been made into powder, but according to experiments conducted by the present inventors, it is preferable to set the upper limit to 20 meshes. If the particles are made coarser than this, they will tend to separate by specific gravity from other flux materials, increasing the risk of component segregation.1.
This makes it difficult to manufacture wires as small as 6 mm. Furthermore, to the B-containing atomized metal powder used in the present invention, elements such as Ni, Cr, and MO, which have been conventionally used for the purpose of improving the performance of weld metal, may be added singly or in combination, if necessary, to improve the weld metal. Properties such as tensile properties, impact properties and cracking properties can also be improved.

同様にして、このアトマイズド金属粉にはＢ元素と同時
に適当量のＴｉ，Ｚｒ，Ａｌなどの脱酸性元素を添加し
、Ｂの歩留りを改善したり、Ｂ−Ｔｉの効果を最大限に
発揮させることもできる。Similarly, an appropriate amount of deoxidizing elements such as Ti, Zr, and Al are added to this atomized metal powder at the same time as element B to improve the yield of B and maximize the effect of B-Ti. You can also do that.

また、本発明ワイヤに充填するフラツクスは上記Ｂ含有
アトマイズド金属粉を必須成分とするが、その他脱酸性
元素、鉄粉、スラグ生成剤、ガス発生剤、アーク安定剤
など一般に潜弧溶接材料に使用されているフラツクスを
添加し、主として溶接金属の清浄化を促進し、さらにじ
ん性の向上を図ることができる。特にＴｉ材料の添加は
Ｂのじん性改善を有効にする上で、極めて重要である。In addition, the flux filled in the wire of the present invention has the above-mentioned B-containing atomized metal powder as an essential component, but also includes deoxidizing elements, iron powder, slag forming agents, gas generating agents, arc stabilizers, etc. commonly used in submerged arc welding materials. By adding the flux that has been added to the weld metal, it is possible to mainly promote the cleaning of the weld metal and further improve the toughness. In particular, the addition of Ti material is extremely important in effectively improving the toughness of B.

Ｔ１を溶接金属に添加する方法としては合金およびまた
は化合物の形態でそれぞれワイヤ若しくは潜弧フラツク
スに添加することができる。そして、いずれの方法によ
つても溶接金属中のＴｉ量は０．００４〜０．０８重量
％の範囲にコントロールすることにより本発明範囲のＢ
元素添加で最高のじん性を得ることができる。ところで
、本発明ワイヤの外皮金属は一般に極軟鋼を使用するが
ワイヤ外皮金属から合金元素を添加する必要のある場合
は、その目的に合つた低合金鋼などの合金鋼をも使用す
ることができる。T1 can be added to the weld metal in the form of an alloy and/or compound to the wire or latent arc flux, respectively. In either method, by controlling the amount of Ti in the weld metal within the range of 0.004 to 0.08% by weight, B
The highest toughness can be obtained by adding elements. Incidentally, the sheath metal of the wire of the present invention is generally made of extremely mild steel, but if it is necessary to add alloying elements to the wire sheath metal, alloy steels such as low-alloy steel suitable for the purpose may also be used. .

実施例 １表１に試作ワイヤにおける充填フラツクスの
配合例を示す。Example 1 Table 1 shows an example of the composition of the filling flux in the prototype wire.

表１においてＡ６．ｌ，２，３，６，７，８，９および
１０はいずれも本発明のシームレスワイヤの実施例であ
り．／Ｔ６．４および．４６．５はボロン含有量をフラ
ツクス中で１重量％および３２重量％にしたシームレス
ワイヤである。滝１１はシームレスワイヤではあるが、
ボロン添加源としてフエロボロン（２０重量％ボロン）
の形で添加した参考例である。In Table 1, A6. 1, 2, 3, 6, 7, 8, 9 and 10 are all examples of seamless wires of the present invention. /T6.4 and . 46.5 is a seamless wire with a boron content of 1% and 32% by weight in the flux. Although waterfall 11 is a seamless wire,
Ferroboron (20% boron by weight) as a boron addition source
This is a reference example in which it was added in the form of

一方Ａ６．ｌ２と滝１３は従来のシームを有するフラツ
クス入りワイヤの参考例である。いづれも固着剤として
珪酸カリ又は珪酸ソーダにて配合フラツクスを粉粒状に
した後、軟鋼外皮に１５重量％当て充填し、伸線工程を
経て、１．６ｍ７！ｌ径のワイヤを製造した。なお、ワ
イヤ中の水分除去及び伸線を容易にするため伸線途中で
７０『Ｃにて焼鈍した。更にシームレスワイヤの場合は
、送給性、給電性及び耐錆性を向上させる自的でワイヤ
表面に銅みつきを施した。これら１３種の溶接ワイヤに
よるガスシールドアーク溶接の溶着金属の各種試験結果
を表２に示した。On the other hand, A6. 12 and waterfall 13 are examples of flux-cored wires with conventional seams. In each case, the blended flux was pulverized using potassium silicate or sodium silicate as a fixing agent, and then filled into a mild steel shell at 15% by weight, and then subjected to a wire drawing process. A wire of l diameter was manufactured. In addition, in order to facilitate the removal of moisture in the wire and the wire drawing, the wire was annealed at 70°C during the wire drawing. Furthermore, in the case of seamless wires, the wire surface is coated with copper to improve feeding performance, power feeding performance, and rust resistance. Table 2 shows the results of various tests on deposited metal in gas-shielded arc welding using these 13 types of welding wires.

溶着金属試験は、供試鋼板としてＳＭ一４１Ｂ板厚２０
ｍｍを用いて溶接条件は電流４５０Ａ、電圧４０、溶接
速度１５ＣＴｒＬ／ＭｉｎおよびＣＯ２ガス流量２０１
／Ｍｉｎを採用して溶接入熱７２ＫＪ／ＣＴＩＬなる大
入熱溶接をおこない、これにより得られた試験片につき
実施した。拡散性水素量は１０日間気温２６つＣ〜２９
℃、相対湿度７６〜８５％なる室内に放置したワイヤを
用いて、溶接条件は電流３００Ａ．．ＤＣ…；電圧３０
Ｖ；速度３０ｃｍ／Ｍｉｎ；ＣＯ２流量２０！／Ｍｉｎ
でもつてＪＩＳＺ３ｌｌ３に定められたグリセリン置換
法により求めた。表２から明らかな如く、腐１，２，３
，６，７，８，９および１０の本発明のシームレスワイ
ヤによる溶着金属中の拡散性水素量は極めて少なく約０
．２〜０．３ｍ１／Ｍｉｎであつた。The weld metal test was conducted using SM-41B plate thickness 20 as the test steel plate.
The welding conditions are current 450A, voltage 40, welding speed 15CTrL/Min and CO2 gas flow rate 201mm.
/Min, high heat input welding with a welding heat input of 72 KJ/CTIL was performed, and the test pieces obtained thereby were tested. The amount of diffusible hydrogen is 10 days at a temperature of 26 C to 29 C.
℃ and a relative humidity of 76 to 85% in a room, and the welding conditions were a current of 300A. ．． DC...; Voltage 30
V; Speed 30cm/Min; CO2 flow rate 20! /Min
It was determined by the glycerin substitution method specified in JIS Z3ll3. As is clear from Table 2, rot 1, 2, 3
, 6, 7, 8, 9 and 10 of the present invention, the amount of diffusible hydrogen in the weld metal is extremely small, about 0.
．． It was 2 to 0.3 m1/min.

しかも衝撃じん性も非常にすぐれており本発明によるワ
イヤの卓越性が明らかにされた。特にＡｒ−ＣＯ２溶接
用に設計した．４６．８および滝９のワイヤの場合は衝
撃値が一段と向上し、拡散性水素量はより減少している
。Furthermore, the impact toughness was also very good, demonstrating the superiority of the wire according to the present invention. Especially designed for Ar-CO2 welding. In the case of wires of No. 46.8 and No. 9, the impact value is further improved and the amount of diffusible hydrogen is further reduced.

これに対しボロンを通常のフエロボロン（２０重量％）
で添加した参考ワイヤ腐１１の場合は拡散性水素は少な
いが、衝撃値のバラツキが大きいという問題がある。こ
れはフエロボロンの品質が高いため溶着金属へ所定量付
与するためには、フラツクス配合比として極めて微量添
加とならざるを得ないため、偏析あるいは焼損により溶
着金属へのボロン量が一定しなかつたものと考えられる
。これに対し本発明ワイヤによる溶接金属にはボロン量
が安定に付与されていることが実証され、鉄基アトマイ
ズド金属粉の形態で添加する本発明の優位性が明らかに
なつた。また、本発明の滝１，２，３，６，７，８，９
および１０ワイヤでは衝撃値は極めて高くかつそのばら
つき度合も少なく大入熱ガスシールドアーク溶接に十分
適用出来る性能を有していることが判る。In contrast, boron is normal feroboron (20% by weight)
In the case of the reference wire rot 11 added in the above example, there is little diffusible hydrogen, but there is a problem in that the impact value varies widely. This is due to the high quality of ferroboron, so in order to add the specified amount to the weld metal, it has to be added in an extremely small amount in the flux mixture ratio, so the amount of boron in the weld metal is inconsistent due to segregation or burnout. it is conceivable that. On the other hand, it has been demonstrated that boron is stably added to the weld metal produced by the wire of the present invention, and the superiority of the present invention, which is added in the form of iron-based atomized metal powder, has become clear. In addition, waterfalls 1, 2, 3, 6, 7, 8, 9 of the present invention
It can be seen that the impact value of the 10 wire is extremely high and the degree of variation is small, and the impact value is sufficiently applicable to high heat input gas shielded arc welding.

これに対し滝５の参考ワイヤは溶着金属中のＢが８２Ｐ
Ｆ１と適正添加範囲から外れているため鋼が硬化し、こ
の結果引張強度が高くなりすぎ６０ｋｇ／ＭｌＬを超え
た。On the other hand, the reference wire of Taki 5 has 82P of B in the weld metal.
Because F1 was out of the appropriate addition range, the steel hardened, and as a result, the tensile strength became too high, exceeding 60 kg/MlL.

また伸びも２１％と低い値となつた。さらに衝撃値も本
発明ワイヤに比べ著しく低い値となつた。また、参考ワ
イヤ滝４では溶着金属中のボロンが不足するため、引張
強度は軟鋼用としてほぼ満足である。The elongation was also low at 21%. Furthermore, the impact value was significantly lower than that of the wire of the present invention. Further, since the reference wire waterfall 4 lacks boron in the weld metal, the tensile strength is almost satisfactory for use with mild steel.

本発明ワイヤに比べ衝撃じん性の改善効果は極めて小さ
いことがわかる。更にワイヤ外皮の合せ目のある参考ワ
イヤ滝１２と．／Ｆ６ｌ３では溶着金属中の拡散性水素
が本発明のシームレスワイヤに比べて極めて多くなつて
いるがこれは充てんフラツタスが吸湿した結果と考えら
れる。It can be seen that the effect of improving impact toughness is extremely small compared to the wire of the present invention. Furthermore, there is a reference wire waterfall 12 with a seam of the wire sheath. /F6l3 has an extremely large amount of diffusible hydrogen in the weld metal compared to the seamless wire of the present invention, which is thought to be a result of the filled flatus absorbing moisture.

かかるワイヤは一般の軟鋼および５０ＨＴ鋼には適用で
きても、ボロン元素添加により溶接金属が焼入硬化され
ている場合あるいはＮｉ，Ｃｒ，ＭＯなどの合金元素を
添加し強度を維持させている６０ＨＴ以上の高張力鋼の
場合には水素起因の割れやぜい化を来たし易いため適用
は困難である。以上の結果から明らかな如く、本発明に
なるシームレスワイヤはガスシールドアークの大入熱溶
接において極めて高いじん性がばらつくことなく維持出
来るため大電流高能率に、しかも従来、拡散性水素量が
多いとの理由でフラツクス入りワイヤの種々の長所を発
揮出来なかつた分野たとえば高張力鋼、Ｃｒ−ＭＯ鋼な
ど低合金鋼の溶接に従来はソリッドワイアによる小入熱
多層盛ＭＩＧ溶接法で施工されたところにも経済的にか
つ容易に施工しうるＣＯ２溶接法で十分に、健全で高品
質な溶接継手部を確保しうるものである。Although such wires can be applied to general mild steel and 50HT steel, the weld metal is quench-hardened by adding boron, or 60HT is made by adding alloying elements such as Ni, Cr, and MO to maintain strength. In the case of the above-mentioned high tensile strength steels, it is difficult to apply them because they are prone to hydrogen-induced cracking and brittleness. As is clear from the above results, the seamless wire of the present invention can maintain extremely high toughness without variation in gas-shielded arc high heat input welding, allowing high current and high efficiency. For example, welding of low-alloy steels such as high-strength steel and Cr-MO steel was conventionally carried out using the low heat input multi-layer welding MIG welding method using solid wire. The CO2 welding method, which can be carried out economically and easily, is sufficient to ensure a sound and high-quality welded joint.

実施例 ２ 第３表に試作ワイヤにおける充填フラツクスの配合例を
示す。Example 2 Table 3 shows an example of the composition of the filling flux in the prototype wire.

第３表において滝１〜．３６．４および滝７〜滝１０は
いずれも本発明ワイヤの実施例であり、滝５および廃６
はＢ含有量をフラツクス中で１重量％および３３重量％
と本発明の範囲外にしたシームレスワイヤの参考例であ
る。．／Ｆ６．ｌｌはＢ添加源として通常のＦｅ−Ｂ（
２０％Ｂ）の形態でＢを添加したシームレスワイヤの参
考例である。一方、Ａ６．ｌ２〜．／Ｉ６．ｌ４はアト
マイズドＢを含んでいるものの従来のシームを有するフ
ラツクス入りワイヤの参考例である。いずれも固着剤と
して珪酸カリ又は珪酸ソーダにて配合フラツクスを粉粒
状になした後、軟鋼外皮に１３重量％当て充填し、伸線
工程を経て６．４および４，８ｍｍ径ワイヤを製造した
。なおワイヤ中の水分除去および伸線を容易にするため
、伸線途中で７００℃にて焼鈍したことは前述のガスシ
ールドアーク溶接用の場合と同様である。In Table 3, waterfall 1~. 36.4 and waterfalls 7 to 10 are all examples of the wire of the present invention, waterfall 5 and waste 6
The B content is 1% by weight and 33% by weight in the flux.
This is a reference example of a seamless wire outside the scope of the present invention. ．． /F6. ll is the usual Fe-B (
This is a reference example of a seamless wire to which B is added in the form of 20% B). On the other hand, A6. l2~. /I6. 14 is a reference example of a flux-cored wire containing atomized B but with a conventional seam. In each case, the blended flux was made into powder using potassium silicate or sodium silicate as a fixing agent, and then 13% by weight of the flux was filled into a mild steel shell, followed by a wire drawing process to produce wires with diameters of 6.4 and 4.8 mm. Note that in order to facilitate the removal of moisture in the wire and the wire drawing, the wire was annealed at 700° C. during the wire drawing, as in the case for gas shielded arc welding described above.

さらに、シームレスワイヤの場合は送給性、給電性およ
び耐錆性を向上させる目的でワイヤ表面に鋼メツキを施
した。これら１４種の潜弧溶接ワイヤによる溶接金属の
各種試験結果を第４表に示した。Furthermore, in the case of seamless wires, steel plating was applied to the wire surface for the purpose of improving feeding performance, power feeding performance, and rust resistance. Table 4 shows the results of various tests on weld metal using these 14 types of submerged arc welding wires.

．Ｓ．ｌ〜７１６．６および滝１４のワイヤはＴｌＯ２
−ＢａＯ−Ａｌ２Ｏ３系溶融形潜弧溶接用フラツクスを
伴用し、Ａｌｘ７〜滝１３のワイヤは鉄粉−ＭｇＯ−Ｓ
ｌＯ２系焼成形フラツクスを併用した。溶接金属の性能
はＸ開先に機械加工した３５ｍｍ厚の５０ＨＴ鋼板を６
．４ｍ７ｎ径ワイヤを用いて表裏１パス溶接し、この溶
接部を調べたものである。この時の母材の開先角度は裏
側６０度仕上げ側７０度であり溶接条件は電流１２００
Ａ、電圧４０、速度２３ｃＴｎ／―であつた。なお拡散
性水素量は２０ｔ×４０ＷＸ１３０Ｌ寸法の試験片上に
気温２６〜２９゜Ｃ、相対湿度７６〜８５％の室内に１
０日間放置した４．８ｍ１Ｌ径ワイヤを用いて、電流８
００Ａ、電圧３２Ｖ、速度３５０ｆｎ／Ｍｉｎなる条件
でビードを溶着し、グリセリン置換法により求めたもの
である。第４表から明らかな如く、洗１〜．／Ｖ）．５
および滝７〜滝１０の本発明ワイヤによる溶着金属中の
拡散性水素量は極めて少なく併用するフラツクスによつ
ても影響されるが約０．２〜０．６ＣＣ／１００ｆ！金
属であつた。．． S. l~716.6 and waterfall 14 wires are TlO2
-BaO-Al2O3-based melting type submerged arc welding flux is used, and the wires from Alx7 to Waterfall 13 are iron powder-MgO-S
A lO2-based sintered flux was also used. The performance of the weld metal is as follows: 35mm thick 50HT steel plate machined into an
．． One pass of front and back welding was performed using 4m7n diameter wire, and this welded part was examined. At this time, the groove angle of the base metal is 60 degrees on the back side and 70 degrees on the finished side, and the welding conditions are 1200 degrees
A, voltage was 40, and speed was 23 cTn/-. The amount of diffusible hydrogen was measured by placing 1 liter on a test piece with dimensions of 20 tons x 40 W x 130 L in a room with an air temperature of 26 to 29°C and a relative humidity of 76 to 85%.
Using a 4.8m1L diameter wire that had been left for 0 days, a current of 8
The bead was welded under the conditions of 00A, voltage 32V, and speed 350fn/min, and was determined by the glycerin substitution method. As is clear from Table 4, wash 1~. /V). 5
The amount of diffusible hydrogen in the metal welded by the wire of the present invention in Taki 7 to Taki 10 is extremely small and is influenced by the flux used in combination, but it is about 0.2 to 0.6 CC/100f! It was hot metal.

しかもＢ元素の働きで衝撃じん性も非常にすぐれており
、本発明ワイヤの卓越性が明らかにされた。これに対し
、Ｂを通常のＦｅ一Ｂ（２０％Ｂ）により添加した参考
ワイヤ腐１１の場合は拡散性水素は少ないが衝撃値のば
らつきが大きいという問題がある。これはＢの品位が高
いため、溶接金属に所定量のＢを付与するためにはフラ
ツクス配合比が極めて微量とならざるを得なかつたため
、偏析あるいは焼損により溶接金属へのＢが一定しなか
つたものと考えられる。これに対し、本発明ワイヤによ
る溶接金属にはＢが安定して付与されていることが実証
され、鉄基アトマイズド金属粉の形態でＢを含有する本
発明ワイヤの優性が明らかとなつた。すなわち、第４表
から明らかな如く、Ａ６．ｌ〜Ａ６．４および滝７〜廃
９の本発明ワイヤでは衝撃値は極みて高く、かつそのば
らつき度合も少なく大入熱溶接に十分適用できる性能を
有していることが判る。Ｘ）．５の参考ワイヤの場合は
溶接金属中のＢが不足するため、鋼の焼入れ効果が十分
でなく、衝撃じん性の改善効果は認められない。Moreover, due to the action of element B, the impact toughness was also very excellent, demonstrating the superiority of the wire of the present invention. On the other hand, in the case of the reference wire rot 11 in which B was added in the form of normal Fe-B (20% B), there was a problem in that although there was little diffusible hydrogen, the impact value varied widely. This is due to the high quality of B, so in order to add a predetermined amount of B to the weld metal, the flux mixing ratio had to be extremely small, which resulted in uneven B being applied to the weld metal due to segregation or burnout. considered to be a thing. On the other hand, it was demonstrated that B was stably added to the weld metal using the wire of the present invention, and the superiority of the wire of the present invention containing B in the form of iron-based atomized metal powder became clear. That is, as is clear from Table 4, A6. It can be seen that the wires of the present invention of No. 1 to A6.4 and Taki No. 7 to No. 9 have extremely high impact values, and have a small degree of variation, and have performance that can be sufficiently applied to high heat input welding. X). In the case of the reference wire No. 5, since there is insufficient B in the weld metal, the effect of hardening the steel is insufficient, and no impact toughness improvement effect is observed.

一方、．４６６の参考ワイヤでは溶接金属中のＢが８８
ＰＦと適正添加範囲から外れているため、鋼が硬化し、
この結果引張強度が高くなりすぎ６０ｋ９／ＭｌＬを超
えた。また、伸びも２１％と低い値となつた。さらに衝
撃じん性は本発明ワイヤによるものより著るしく劣化し
た。さらに、ワイヤ外皮に合せ目のある参考ワイヤＡ６
．ｌ２およびＡ６．ｌ３では溶着金属中の拡散性水素が
本発明ワイヤに比べ極めて多くなつている。on the other hand,. 466 reference wire has B in the weld metal of 88
Because the PF is outside the appropriate addition range, the steel hardens,
As a result, the tensile strength became too high, exceeding 60k9/MlL. Furthermore, the elongation was also a low value of 21%. Furthermore, the impact toughness was significantly worse than that of the wire of the present invention. Furthermore, a reference wire A6 with seams on the wire sheath
．． l2 and A6. In 13, the amount of diffusible hydrogen in the weld metal is significantly higher than in the wire of the present invention.

かかるワイヤは一般の軟鋼材には適用できても、Ｂ元素
添加により溶接金属が硬化している場合、あるいはＮｉ
，Ｃｒ，ＭＯなどの合金元素を添加し、強度を維持して
いる高張力鋼の場合には水素起因の割れやぜい化を来た
し易いため適用は困難である。以上の結果から明らかな
如く、本発明ワイヤは潜弧溶接に適用し極めて高いじん
性がはらつくことなく維持でき、かつ拡散性水素量も極
めて少ない。Although such wires can be applied to general mild steel materials, they may be used in cases where the weld metal is hardened due to the addition of B elements, or when Ni
, Cr, MO, and other alloying elements are added to maintain the strength of high-strength steel, which is difficult to apply because it is susceptible to hydrogen-induced cracking and embrittlement. As is clear from the above results, the wire of the present invention can be applied to submerged arc welding and maintain extremely high toughness without fluctuations, and the amount of diffusible hydrogen is also extremely small.

このため、従来水素が多いとの理由でフラツクス入りワ
イヤの種々の特長が発揮できなかつた分野、たとえば高
張力鋼Ｃｒ−ＭＯ鋼など低合金鋼の溶接、前述のガスシ
ールドアーク溶接への適用とともにじゆう分な性能を有
するシームレスワイヤにより容易に適用しうる道が開拓
でき、産業界に貢献するところ極めて大である。For this reason, flux-cored wires can be used in fields where the various features of flux-cored wires have not been fully demonstrated due to the high hydrogen content, such as welding of low-alloy steels such as high-strength steel and Cr-MO steel, and the aforementioned gas-shielded arc welding. Seamless wires with reasonable performance will open up a path to easy application, and will greatly contribute to industry.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はボロン源の種類と溶着金属の衝撃値のばらつき
度合の関係を表わす図、第２図は鉄基アトマイズド金属
粉中のボロン含有量と溶着金属の衝撃じん性の関係を表
わす図、第３図はＢ含有アトマイズド金属粉のフラツク
ス中への添加量と溶着金属の衝撃値の関係を表わす図、
第４図は所定ワイヤ径にした後ワイヤを大気中に放置し
た日数とそのワイヤで溶接した溶着金属中の拡散性水素
量との関係を表わす図、第５図は第４図と同様にワイヤ
放置日数とＵ形拘束割れ試験による溶接ビード断面割れ
率との関係を表わす図である。Figure 1 is a diagram showing the relationship between the type of boron source and the degree of variation in the impact value of the weld metal, Figure 2 is a diagram showing the relationship between the boron content in iron-based atomized metal powder and the impact toughness of the weld metal, Figure 3 is a diagram showing the relationship between the amount of B-containing atomized metal powder added to the flux and the impact value of the weld metal;
Figure 4 is a diagram showing the relationship between the number of days a wire is left in the atmosphere after it has been made to a predetermined wire diameter and the amount of diffusible hydrogen in the deposited metal welded with that wire. FIG. 3 is a diagram showing the relationship between the number of days of storage and the weld bead cross-sectional cracking rate obtained by a U-shaped restraint cracking test.

Claims (1)

【特許請求の範囲】[Claims] １ ０．５超〜１０．０重量％のボロンを含むアトマイ
ズド金属粉を１．５〜３０．０重量％含有することを必
須としたフラックスに固着剤を添加し、粉粒状になした
るものを充填してなるアーク溶接用高じん性シームレス
ワイヤ。1 A flux that is made into powder by adding a fixing agent to a flux that must contain 1.5 to 30.0% by weight of atomized metal powder containing more than 0.5 to 10.0% by weight of boron. High toughness seamless wire for arc welding made by filling.