JPH0413410B2 - - Google Patents
Info
- Publication number
- JPH0413410B2 JPH0413410B2 JP19976683A JP19976683A JPH0413410B2 JP H0413410 B2 JPH0413410 B2 JP H0413410B2 JP 19976683 A JP19976683 A JP 19976683A JP 19976683 A JP19976683 A JP 19976683A JP H0413410 B2 JPH0413410 B2 JP H0413410B2
- Authority
- JP
- Japan
- Prior art keywords
- melted
- plasma
- plasma arc
- melting
- plasma torch
- 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
- 239000000463 material Substances 0.000 claims description 87
- 239000002184 metal Substances 0.000 claims description 63
- 229910052751 metal Inorganic materials 0.000 claims description 63
- 238000002844 melting Methods 0.000 claims description 58
- 230000008018 melting Effects 0.000 claims description 56
- 238000000034 method Methods 0.000 claims description 14
- 239000013078 crystal Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000005204 segregation Methods 0.000 description 11
- 239000012298 atmosphere Substances 0.000 description 10
- 239000007789 gas Substances 0.000 description 8
- 238000007711 solidification Methods 0.000 description 8
- 230000008023 solidification Effects 0.000 description 8
- 229910000601 superalloy Inorganic materials 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000011261 inert gas Substances 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 230000008901 benefit Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000001112 coagulating effect Effects 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011978 dissolution method Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000000289 melt material Substances 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000010313 vacuum arc remelting Methods 0.000 description 1
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、一般的な金属材料はもちろんのこ
と、とくに高融点金属や超合金等の難溶解、難加
工性材料の溶解に使用するのに適したプラズマア
ーク溶解方法および溶解装置に関するものであ
る。[Detailed Description of the Invention] (Field of Industrial Application) This invention can be used to melt not only general metal materials, but also materials that are difficult to melt and process, such as high melting point metals and superalloys. The present invention relates to a plasma arc melting method and melting apparatus suitable for.
（従来技術）
従来、プラズマアークを使用したプラズマアー
ク溶解装置としては、例えば、第１図に示す構造
のものがあつた。すなわち、第１図において、１
は密閉容器、２，２は密閉容器１の側部に固定し
たプラズマトーチ、３は同じく密閉容器１の上部
に上下移動可能に取付けた被溶解材、４は水冷鋳
型、５は同じく密閉容器１の下部に上下移動可能
に取付けた凝固金属受、６は陰極側を前記プラズ
マトーチ２，２に接続すると共に陽極側に凝固金
属受５側に接続したプラズマアーク発生用電源で
ある。(Prior Art) Conventionally, as a plasma arc melting apparatus using a plasma arc, there is, for example, a structure shown in FIG. That is, in Figure 1, 1
2 is a closed container, 2 is a plasma torch fixed to the side of the closed container 1, 3 is a material to be melted which is also attached to the top of the closed container 1 so as to be movable up and down, 4 is a water-cooled mold, and 5 is also the closed container 1 A coagulating metal receiver 6, which is vertically movably attached to the lower part of the plasma arc generator, is a power source for generating a plasma arc, whose cathode side is connected to the plasma torches 2, 2, and whose anode side is connected to the coagulating metal receiver 5 side.
このようなプラズマアーク溶解装置による被溶
解材３の溶解は、凝固金属受５の上端部分を水冷
鋳型４内に位置させた状態において、密閉容器１
内を不活性な雰囲気にし、プラズマアーク発生用
電源５より通電を開始して、プラズマトーチ２
と、凝固金属受６上に置いた図示しない着弧部材
との間でプラズマアーク７を発生させ、このプラ
ズマアーク７の熱によつて被溶解材３の下端部分
を溶解して、水冷鋳型４内に落下させ、水冷鋳型
４内にたまつた溶融金属８を水冷鋳型４により強
制凝固させ、この間凝固金属受５を徐々に降下さ
せて凝固金属９を得るものである。 Melting of the material 3 to be melted by such a plasma arc melting device is carried out in a closed container 1 with the upper end portion of the solidified metal receiver 5 positioned within the water-cooled mold 4.
Create an inert atmosphere inside the torch, start energizing the plasma arc generation power source 5, and turn the plasma torch 2 on.
A plasma arc 7 is generated between the metal holder 6 and an arc starting member (not shown) placed on the solidified metal receiver 6, and the lower end portion of the material 3 to be melted is melted by the heat of the plasma arc 7. The molten metal 8 collected in the water-cooled mold 4 is forcibly solidified by the water-cooled mold 4, and during this time, the solidified metal receiver 5 is gradually lowered to obtain solidified metal 9.
このようなプラズマアーク溶解装置では、一般
的な金属材料はもちろんのこと、とくに高融点金
属等の難溶解材料の溶解に適しており、溶解時に
おける不純物の吸収も少ないので、高品質の材料
を得るための溶解方法としてすぐれたものであ
る。このプラズマアーク溶解において、溶解の際
にはプラズマアークがプラズマトーチ２の先端と
溶融金属８との間で生じ、溶融金属８は常に過熱
された状態にあつてある程度の溶解深さを保つて
おり、この溶融金属８に加えられるエネルギは大
きいものとなつている。したがつて、溶融金属８
の量は比較的多く、溶融金属８の凝固は水冷鋳型
４の部分でやや早く、中心部分ではそれよりも遅
い緩慢なものとなるため注状晶として凝固するこ
ととなり、溶融金属８の凝固収縮や密度差によつ
て注状晶間で未凝固金属の流動を生じ、マクロ偏
析をひき起こしやすいものであつた。また、凝固
金属（鋳塊）９は水冷鋳型４によつて強制冷却さ
れたものであるため熱応力を伴いやすく、さら
に、プラズマアークによるエネルギは被溶解材３
の溶解のほか、溶融金属８の過熱にも消費され、
溶融金属８は水冷鋳型４によつて絶えず抜熱され
ているため、エネルギ消費量が比較的多いもので
あつた。 This type of plasma arc melting equipment is suitable for melting not only general metal materials but also difficult-to-melt materials such as high-melting point metals, and absorbs few impurities during melting, so it is possible to melt high-quality materials. This is an excellent dissolution method for obtaining In this plasma arc melting, a plasma arc is generated between the tip of the plasma torch 2 and the molten metal 8 during melting, and the molten metal 8 is always in a superheated state and maintains a certain melting depth. , the energy applied to this molten metal 8 is large. Therefore, molten metal 8
The amount of molten metal 8 is relatively large, and the solidification of the molten metal 8 is a little faster in the water-cooled mold 4 part, and slower in the central part, so it solidifies as a poured crystal, and the solidification shrinkage of the molten metal 8 occurs. The flow of unsolidified metal between the cast crystals was caused by the difference in density and density, and this tended to cause macro-segregation. Furthermore, since the solidified metal (ingot) 9 is forcibly cooled by the water-cooled mold 4, it is likely to be accompanied by thermal stress, and furthermore, the energy from the plasma arc is transferred to the melted material 3.
In addition to melting, it is also consumed to overheat the molten metal 8.
Since the molten metal 8 is constantly being subjected to heat removal by the water-cooled mold 4, the amount of energy consumed is relatively large.
（発明の目的）
この発明は、上述した従来のプラズマアーク溶
解に伴う種々の事情に着目してなされたもので、
プラズマアーク加熱により生じた溶融金属の凝固
が著しく早く、溶融金属のたまり部分が非常にわ
ずかでかつ浅いため、均一で且つ微細な等軸晶組
織をもつ凝固金属あるいは完全一方向凝固金属を
得ることが可能であり、とくに数多くの合金元素
を含む超合金の溶解に際しても各成分の偏析を伴
わず、従来の水冷鋳型を使用するプラズマアーク
溶解法、エレクトロスラグ溶解法、真空アーク溶
解法では偏析を生じやすいため問題の多かつた大
型鋳塊の製造も偏析を伴なうことなく容易に行う
ことができ、また、溶解に必要なエネルギも著し
く少なくてすみ、溶解速度も大きなものとするこ
とが可能であるというすぐれた特長をもつプラズ
マアーク溶解方法およびプラズマアーク溶解装置
を提供することを目的としている。(Object of the Invention) This invention was made by focusing on the various circumstances associated with the conventional plasma arc melting described above.
Since the molten metal produced by plasma arc heating solidifies extremely quickly and the pool of molten metal is very small and shallow, it is possible to obtain solidified metal with a uniform and fine equiaxed crystal structure or completely unidirectionally solidified metal. In particular, even when melting superalloys containing many alloying elements, there is no segregation of each component, and conventional plasma arc melting, electroslag melting, and vacuum arc melting methods that use water-cooled molds do not cause segregation. The production of large ingots, which has been a problem due to the tendency to occur, can be easily carried out without segregation, and the energy required for melting is significantly less, and the melting rate can be increased. The object of the present invention is to provide a plasma arc melting method and a plasma arc melting apparatus that have the excellent feature of being possible.
（発明の構成）
この発明によるプラズマアーク溶解方法は、電
源の一方に接続したプラズマトーチの先端と、前
記電源の他方に接続した被溶解材の端部とを対向
させて前記プラズマトーチと被溶解材との間でプ
ラズマアークを発生させ、前記プラズマアークに
よる加熱で前記被溶解材を溶解して落下させ、次
いで凝固させて均一で且つ微細な等軸晶凝固金属
あるいは一方向凝固金属を得ることを特徴とし、
この方法の実施に直接使用するこの発明によるプ
ラズマアーク溶解装置は、プラズマアーク発生用
電源と、前記電源の一方に接続したプラズマトー
チと、前記電源の他方に接続した被溶解材の端部
と前記プラズマトーチの先端とを対向させた状態
で前記被溶解材を保持する被溶解材保持手段と、
前記プラズマトーチと被溶解材との間で発生した
プラズママークにより加熱された被溶解材の液滴
を受ける液滴受手段と、を備えたことを特徴とし
ている。(Structure of the Invention) The plasma arc melting method according to the present invention includes a plasma arc melting method in which the tip of a plasma torch connected to one side of a power source and the end of a material to be melted connected to the other side of the power source are opposed to each other. generating a plasma arc between the metal and the metal, melting the material to be melted by heating by the plasma arc, causing it to fall, and then solidifying it to obtain a uniform and fine equiaxed crystal solidified metal or unidirectionally solidified metal. It is characterized by
The plasma arc melting apparatus according to the present invention, which is directly used for carrying out this method, includes a power source for generating a plasma arc, a plasma torch connected to one of the power sources, an end of the material to be melted connected to the other of the power sources, and a plasma arc melting device connected to the other power source. A material holding means for holding the material to be melted in a state where the tip of the plasma torch is opposed to the material to be melted;
The present invention is characterized by comprising a droplet receiving means for receiving droplets of the material to be melted heated by the plasma mark generated between the plasma torch and the material to be melted.
この発明おいて使用されるプラズマトーチは、
Ar、N2、He等の不活性ガスやこの不活性ガスを
主体とする混合ガス等を作動ガスとしたものなど
があり、例えばタングステン非消耗電極を用いて
この電極をプラズマアーク発生用電源の陰極側に
接続すると共に前記電源の陽極側をプラズマトー
チ外のプラズマアーク発生端に接続したいわゆる
移送式のものが用いられるが、プラズマトーチの
細かな構造は特に限定されない。また、プラズマ
トーチの本数も限定されない。そして、必要に応
じて、プラズマアークの電流を周期的に変化させ
たり、プラズマアークの向きを周期的に変化させ
るためにプラズマトーチを揺動させたりすること
もできる。 The plasma torch used in this invention is
There are working gases such as inert gases such as Ar, N 2 and He, or mixed gases mainly composed of these inert gases. A so-called transfer type torch is used in which the cathode side is connected and the anode side of the power source is connected to a plasma arc generating end outside the plasma torch, but the detailed structure of the plasma torch is not particularly limited. Further, the number of plasma torches is not limited either. If necessary, the plasma torch can also be oscillated to periodically change the current of the plasma arc or to periodically change the direction of the plasma arc.
他方、被溶解材は、一般的な金属のほか、とく
に高融点金属や超合金等の難溶解、難加工性材料
を使用することもでき、特に限定されない。ま
た、被溶解材の本数も限定されない。そして、必
要に応じて、被溶解材の端部での溶解が平均的に
行われるように、被溶解材を回転させたり、周期
的に揺動させたりすることも可能である。 On the other hand, the material to be melted is not particularly limited, and in addition to general metals, materials that are difficult to melt and process, such as high-melting point metals and superalloys, can also be used. Moreover, the number of materials to be melted is not limited either. If necessary, the material to be melted can be rotated or oscillated periodically so that the ends of the material are evenly melted.
この被溶解材は、所定の合金成分を有する例え
ば真空誘導溶解した注状凝固金属が使用される
が、そのほか、例えば所望合金成分にあわせて複
数種の金属棒を束ねたものとし、この束金属棒と
プラズマトーチとを対向させてプラズマアークの
熱により束状金属棒を溶解し、液滴として落下さ
せて凝固させることにより、所定成分の合金を得
るようになすことも可能である。 The material to be melted is, for example, a vacuum induction melted cast solidified metal having a predetermined alloy composition, but it is also possible to use, for example, a bundle of metal rods of multiple types according to the desired alloy composition. It is also possible to obtain an alloy of a predetermined composition by arranging the rods and a plasma torch to face each other, melting the bundled metal rods by the heat of the plasma arc, and causing the metal rods to fall as droplets and solidify.
そして、１本または数本のプラズマトーチと同
じく１本または数本の被溶解材とをギヤツプをお
いて突き合わせる態様としては、プラズマトーチ
および被溶解材の両方を水平状態にして各端部を
突き合わせる態様のほか、プラズマトーチおよび
被溶解材のいずれか一方を水平状態にすると共に
いずれか他方を傾斜状態とする態様や、両方共を
傾斜状態とする態様、さらには被溶解材を垂直状
態にしかつプラズマトーチをその下部側から上向
きに傾斜状態とする態様など、種々の形態があ
る。そして、この被溶解材を保持する被溶解材保
持手段としては、従来の消耗電極式アーク溶解炉
において使用されているもの、その他適宜の構成
を有する被溶解材移動可能式のものが使用され
る。 As for the embodiment in which one or several plasma torches and one or several pieces of material to be melted are brought into contact with a gap, both the plasma torch and the material to be melted are held horizontally, and each end is In addition to the mode in which the plasma torch and the material to be melted are in a horizontal state and the other is in an inclined state, the mode in which both are in an inclined state, and the mode in which the material to be melted is in a vertical state. There are various configurations, such as a configuration in which the plasma torch is tilted upward from the lower side. As the material holding means for holding the material to be melted, the one used in the conventional consumable electrode type arc melting furnace, or the one having an appropriate structure that allows the material to be melted to be moved is used. .
また、雰囲気は必らずしも真空でなくともよ
く、減圧から加圧状態（例えば0.1〜10atm）の
間で適宜選定することができる。したがつて、例
えば、Mn、Cr等のような高蒸気圧元素の場合に
は当該元素の蒸発が生じがたい比較的高圧の雰囲
気で溶解すれば、上記元素の蒸発損失が著しく少
ない状態で高い歩留りで溶解することが可能であ
る。さらに必要に応じて雰囲気を減圧した状態と
すれば、蒸気圧の高い不純物が除去されるように
なり、これによつて被溶解材の精製も可能であ
る。 Further, the atmosphere does not necessarily have to be a vacuum, and can be appropriately selected from a reduced pressure to a pressurized state (for example, 0.1 to 10 atm). Therefore, for example, in the case of high vapor pressure elements such as Mn, Cr, etc., if the elements are melted in a relatively high pressure atmosphere where evaporation of the elements is difficult to occur, the evaporation loss of the elements is extremely small and high vapor pressure is achieved. It is possible to dissolve at a yield. Furthermore, if the atmosphere is reduced in pressure as necessary, impurities with high vapor pressure can be removed, thereby making it possible to purify the material to be melted.
さらにまた、上記雰囲気は不活性雰囲気とする
ことも場合によつては望ましく、例えばN2、
Ar、He等の不活性ガスを使用するほか、これら
のガスを主体とした不活性な混合ガスやH2ガス
その他非酸化性ガス等の雰囲気とすることもでき
る。そして、例えば、窒素含有量を多くする
AlN細粒鋼の場合に、雰囲気をN2として加室に
利用することもできる。 Furthermore, it may be desirable in some cases for the atmosphere to be an inert atmosphere, such as N 2 ,
In addition to using an inert gas such as Ar or He, an atmosphere such as an inert mixed gas mainly composed of these gases, H 2 gas or other non-oxidizing gas can also be used. And, for example, increase the nitrogen content
In the case of AlN fine-grained steel, N 2 atmosphere can also be used for the chamber.
そのほか、被溶解材がプラズマアークの熱によ
つて滴下した際、その液滴を受ける液滴受手段と
しては、耐火物容器や金属容器などが使用され、
使用形態によつて予熱鋳型、断熱鋳型、水冷鋳型
などが使用される。また、この液滴受手段は、静
置、重心回転、偏心回転、昇降（下方引出し）等
の適宜の構成のものを選んで採用することがで
き、例えば、鋳型を回転させることによつて液滴
を均一に分散させることが可能となる。さらに、
液滴受手段の形状も円柱形、環状形、長方体形
等々の種々の形状のものとすることができ、例え
ば環（管）状の凝固塊を得る場合には、環状の鋳
型を回転可能に設置し、この環状の鋳型を回転さ
せつつ、プラズマアークにより加熱された被溶解
材の液滴が上記鋳型内に落下するようになせばよ
い。 In addition, when the material to be melted drops due to the heat of the plasma arc, a refractory container or a metal container is used as a droplet receiving means to receive the droplets.
Depending on the type of use, preheating molds, insulation molds, water-cooled molds, etc. are used. In addition, this droplet receiving means can be selected from any suitable configuration such as stationary, rotation of center of gravity, eccentric rotation, lifting (downward drawer), etc. For example, by rotating the mold, liquid droplet can be It becomes possible to disperse the droplets uniformly. moreover,
The shape of the droplet receiving means can also be various shapes such as cylindrical, annular, rectangular, etc. For example, when obtaining a ring (tubular) shaped solidified mass, the annular mold can be rotated. The annular mold may be rotated so that droplets of the material to be melted heated by the plasma arc fall into the mold.
さらに、上記液滴受手段は、凝固塊の温度勾配
が大きくなりすぎないように、適宜予熱および断
熱等の手段をとることも場合によつては望まし
い。 Further, in some cases, it may be desirable for the droplet receiving means to take appropriate measures such as preheating and heat insulation to prevent the temperature gradient of the coagulated mass from becoming too large.
さらにまた、液滴受手段を高速回転体とし、被
溶解材の液滴を高速回転する円盤上に落下させて
飛散急冷させることにより、非晶質の粉末を得る
こともできる。 Furthermore, an amorphous powder can also be obtained by using a high-speed rotating body as the droplet receiving means and dropping the droplets of the material to be melted onto a disk rotating at high speed to scatter and rapidly cool the droplets.
そして、上述した各種の条件の中から適宜選択
して、プラズマアーク溶解により凝固金属を得る
に際しては、上記プラズマトーチをプラズマアー
ク発生用電源の例えば陰極側に接続すると共に、
被溶解材を前記電源の陽極側に接続し、前記プラ
ズマトーチの先端と被溶解材の端部とを対向させ
た状態にして、雰囲気を例えば不活性ガスとし、
前記電源を供給することにより前記プラズマトー
チと被溶解材との間でプラズマアークを発生さ
せ、このプラズマアークによる加熱で前記被溶解
材をその端部で溶解し、液滴として落下させる。
このとき、前記液滴受手段においては電源が接続
されておらずしたがつて何らのエネルギも供給さ
れていないので、溶融金属のたまりが非常にわず
かな状態から凝固することとなり、それゆえ等軸
晶凝固あるいは完全一方向凝固の形態をとること
となるため、著しく均一でマクロ偏析も少ない鋳
造組織の凝固金属となる。 Then, when obtaining solidified metal by plasma arc melting by appropriately selecting from the various conditions described above, the plasma torch is connected to, for example, the cathode side of the plasma arc generation power source, and
The material to be melted is connected to the anode side of the power source, the tip of the plasma torch and the end of the material to be melted are opposed to each other, and the atmosphere is set to be an inert gas, for example,
By supplying the power, a plasma arc is generated between the plasma torch and the material to be melted, and heating by the plasma arc melts the material to be melted at its ends, causing the material to fall as droplets.
At this time, since the power source is not connected to the droplet receiving means and therefore no energy is supplied, the molten metal will solidify from a very small amount, and therefore will become equiaxed. Since it takes the form of crystal solidification or completely unidirectional solidification, it becomes a solidified metal with a cast structure that is extremely uniform and has little macro segregation.
そのため、凝固金属の加工性が著しく優れたも
のとなり、従来一般に加工が難かしいとされてい
た超合金等の難加工性材料を任意の形状に鋳造加
工することも可能になるという非常に優れた利点
を得ることができる。また、従来のように溶融金
属の部分が多くかつ水冷鋳型によつて多くの熱が
うばわれるということもないため、被溶解材の溶
解に要するエネルギも非常に少なくて済むと共に
溶解速度もかなり早いものとすることができると
いう利点も得ることができる。さらに、溶解は必
ずしも真空雰囲気でなくともよいため、合金成分
中の蒸気圧が高い元素の揮発損失も生ずることも
ないという利点も有する。 As a result, the workability of solidified metal has become extremely superior, and it has become possible to cast difficult-to-work materials such as superalloys, which were generally considered difficult to work, into any shape. benefits can be obtained. In addition, unlike conventional methods, there is a large amount of molten metal and there is no need to dissipate a lot of heat due to the water-cooled mold, so the energy required to melt the material to be melted is extremely small, and the melting speed is also quite fast. It also has the advantage of being able to be used as an object. Furthermore, since melting does not necessarily have to be carried out in a vacuum atmosphere, there is also the advantage that there is no volatilization loss of elements with high vapor pressure in the alloy components.
この発明においては、溶解用熱源としてプラズ
マアークを使用しているので、アークが著しく安
定なものであり、例えばプラズマトーチの代わり
に別の電極（または被溶解材）を用いて前記被溶
解材と対向させ、両者間の間でアークを飛ばして
前記対向する一方または両方の被溶解材を溶解す
る方法の場合ほどアーク間隔を細かく制御する必
要はなく、プラズマトーチと被溶解材との間隔が
多少変動してもプラズマアークは安定したもので
あるため、溶解の際の制御が容易であつて操業も
安定して行うことができる。 In this invention, since a plasma arc is used as a heat source for melting, the arc is extremely stable. For example, instead of a plasma torch, another electrode (or material to be melted) may be used to It is not necessary to control the arc spacing as finely as in the case of the method of melting one or both of the facing materials by blowing an arc between them, and the distance between the plasma torch and the material to be melted is not as fine as in the case of the method of melting one or both of the materials to be melted. Since the plasma arc is stable even when it fluctuates, control during melting is easy and operations can be performed stably.
実施例 １
第２図はこの発明の実施例１を示す図であつ
て、１１は密閉容器、１２はプラズマトーチ、１
３はプラズマトーチを保持するプラズマトーチ保
持手段、１４は被溶解材、１５は前記被溶解材１
４の端部と前記プラズマトーチ１２の先端とを対
向させた状態で前記被溶解材１４をその軸方向に
移動可能に保持する被溶解材保持手段、１６は液
滴受手段としてのるつぼ、１７はるつぼ１６の回
転手段、１８はプラズマトーチ１２側に陰極を接
続し且つ被溶解材１４側に陽極を接続したプラズ
マアーク発生用電源である。Embodiment 1 FIG. 2 is a diagram showing Embodiment 1 of the present invention, in which 11 is a closed container, 12 is a plasma torch, 1
3 is a plasma torch holding means for holding a plasma torch, 14 is a material to be melted, and 15 is the material to be melted 1
16 is a crucible serving as a droplet receiving means; A rotating means 18 for the crucible 16 is a plasma arc generating power source having a cathode connected to the plasma torch 12 side and an anode connected to the material to be melted 14 side.
次に、被溶解材１４の溶解に際しては、密閉容
器１１内をその連通管１１ａ部分より排気したの
ち不活性ガス例えばArガスで置換すると共に、
プラズマトーチ１２のプラズマ作動ガスとして
Arを用い、電源１８を供給してプラズマトーチ
１２と被溶解材１４との間でプラズマアーク１９
を発生させる。すると、このプラズマアーク１９
によつて加熱された被溶解材１４はその端部より
液滴２０としてるつぼ１６内に落下し、等軸晶凝
固あるいは一方向凝固して凝固金属２１となる。
この溶解の間、被溶解材１４をその溶解速度に合
わせて被溶解材保持手段１５によつて順次プラズ
マトーチ１２側に移動させるようにする。また、
液滴２０を平均的に分散させてより均一な凝固金
属２１が得られるように、必要に応じて回転手段
１７を作動させてるつぼ１６を回転させる。 Next, when melting the material to be melted 14, the inside of the closed container 11 is evacuated from the communication pipe 11a, and then replaced with an inert gas, for example, Ar gas.
As plasma working gas for plasma torch 12
Using Ar, a power source 18 is supplied to create a plasma arc 19 between the plasma torch 12 and the material to be melted 14.
to occur. Then, this plasma arc 19
The heated material 14 falls from its end into the crucible 16 in the form of droplets 20, and undergoes equiaxed crystal solidification or unidirectional solidification to become solidified metal 21.
During this melting, the material to be melted 14 is sequentially moved toward the plasma torch 12 by the material to be melted holding means 15 in accordance with the melting speed. Also,
The crucible 16 is rotated by operating the rotating means 17 as necessary so that the droplets 20 are evenly dispersed and a more uniform solidified metal 21 is obtained.
実施例 ２
第３図はこの発明の実施例２を示す図であつ
て、１１は密閉容器、１２，１２は密閉容器１１
の２箇所に設けたプラズマトーチ、１３，１３は
各プラズマトーチ１２，１２を保持するプラズマ
トーチ保持手段、１４は密閉容器１１の頂上部に
おいて被溶解材保持手段１５により上下移動可能
に設置した被溶解材、１６は液滴受手段としての
るつぼ、１７はるつぼ１６の回転手段、１８はプ
ラズマアーク発生用電源である。Embodiment 2 FIG. 3 is a diagram showing Embodiment 2 of the present invention, in which 11 is a closed container, and 12 and 12 are closed containers 11.
13 is a plasma torch holding means for holding each plasma torch 12, 12, and 14 is a cover installed at the top of the closed container 11 so as to be movable up and down by means of a material holding means 15. A melting material, 16 a crucible as a droplet receiving means, 17 a means for rotating the crucible 16, and 18 a power source for generating a plasma arc.
このような構成とすることによつても、電源１
８を供給して各プラズマトーチ１２，１２と被溶
解材１４との間でプラズマアーク１９を発生させ
ることにより被溶解材１４の溶解が可能であり、
プラズマトーチ１２を２本設置していることから
より太径の被溶解材１４の溶解が短時間のうちに
行われ、被溶解材１４は液滴２０となつてるつぼ
１６内に落下し、直ちに等軸晶凝固あるいは一方
向凝固して凝固金属２１となる。 Even with this configuration, the power supply 1
8 is supplied to generate a plasma arc 19 between each plasma torch 12, 12 and the material to be melted 14, it is possible to melt the material to be melted 14,
Since two plasma torches 12 are installed, the material to be melted 14 with a larger diameter can be melted in a short time, and the material to be melted 14 becomes a droplet 20 and falls into the crucible 16, and is immediately melted. The solidified metal 21 is solidified by equiaxed crystal solidification or unidirectional solidification.
実施例 ３
第４図はこの発明の実施例３を示す図であつ
て、プラズマトーチ１２が３本（ただし、１本は
図示省略）であり、被溶解材１４も３本であつ
て、各々プラズマトーチ１２の先端と被溶解材１
４の下端との間でプラズマアーク１９を発生させ
て、被溶解材１４を溶解させて液滴２０として落
下させ、るつぼ１６内で凝固金属２１とする。Embodiment 3 FIG. 4 is a diagram showing Embodiment 3 of the present invention, in which there are three plasma torches 12 (however, one torch is omitted), there are also three melted materials 14, and each The tip of the plasma torch 12 and the material to be melted 1
A plasma arc 19 is generated between the melted material 14 and the lower end of the melted material 14 to cause the melted material 14 to fall as droplets 20 to solidify metal 21 in the crucible 16.
（具体例）
第２図に示す装置において0.04％Ｃ−17.7％Cr
−3.1％Mo−1.3％Ｗ−14.5％Co−2.44％Al−5.0
％Ti−0.27％Ｂ−0.04％Zr−0.41％Fe−Niよりな
る超合金（Ｕ−720）を真空誘導溶解により注状
（φ80mm）に鋳造凝固させた被溶解材１４を用い、
この被溶解材１４を被溶解材保持手段１５により
保持させた。次いで、密閉容器１１内を1atmの
Ar雰囲気とし、電源１８を供給することによつ
てプラズマトーチ１２と被溶解材１４との間でプ
ラズマアーク１９を発生させ、被溶解材１４の端
部をプラズマアーク１９により加熱溶解し、落下
する液滴２０をるつぼ１６内で凝固させてφ150
mmの凝固金属２１を得た。(Specific example) In the device shown in Figure 2, 0.04%C-17.7%Cr
−3.1%Mo−1.3%W−14.5%Co−2.44%Al−5.0
Using the material to be melted 14, which was made by casting and solidifying a superalloy (U-720) consisting of %Ti-0.27%B-0.04%Zr-0.41%Fe-Ni into a cast shape (φ80 mm) by vacuum induction melting,
This melted material 14 was held by melted material holding means 15. Next, the inside of the airtight container 11 is heated to 1 atm.
By creating an Ar atmosphere and supplying a power source 18, a plasma arc 19 is generated between the plasma torch 12 and the material 14 to be melted, and the end of the material 14 to be melted is heated and melted by the plasma arc 19 and falls. The droplet 20 is solidified in the crucible 16 to a diameter of φ150.
A solidified metal 21 of mm was obtained.
次に、上記凝固金属２１の組織を金属顕微鏡に
より観察したところ、著しく均一でかつ微細な結
晶を有し、マクロ偏析も少ない凝固組織を有する
ものであつた。次いで、上記凝固金属２１の熱間
加工性を評価するため、1170℃×4hrの均質化熱
処理をした後、長手方向に試験片を削り出し、グ
リーブル高速引張試験を行つた。一方、比較とし
て、前記真空誘導溶解時に同時に得た被溶解母材
（φ80mm）を真空アーク再溶解して得た鋳塊
（φ150mm）についても行つた。その結果、第５図
に示すように、本発明の方法で得たものは、真空
アーク再溶解材に比較して全温度範囲で高い絞り
値が得られ熱間加工性にすぐれたものであつた。 Next, when the structure of the solidified metal 21 was observed using a metallurgical microscope, it was found that the solidified metal 21 had extremely uniform and fine crystals, and had a solidified structure with little macro segregation. Next, in order to evaluate the hot workability of the solidified metal 21, after homogenizing heat treatment at 1170° C. for 4 hours, a test piece was cut out in the longitudinal direction and subjected to a Greeble high-speed tensile test. On the other hand, for comparison, an ingot (φ150 mm) obtained by vacuum arc remelting of the base material to be melted (φ80 mm) obtained at the same time during the vacuum induction melting was also conducted. As a result, as shown in Fig. 5, the material obtained by the method of the present invention has a higher reduction of area in the entire temperature range and has excellent hot workability compared to the vacuum arc remelted material. Ta.
（発明の効果）
以上説明してきたように、この発明によれば、
電源の一方に接続したプラズマトーチの先端と、
前記電源の他方に接続した被溶解材の端部とを対
向させて前記プラズマトーチと被溶解材との間で
プラズマアークを発生させ、前記プラズマアーク
による加熱で前記被溶解材を溶解して液滴として
落下させ、これを適宜の液滴受手段により受ける
ことによつて均一で且つ微細な等軸晶凝固金属あ
るいは一方向凝固金属を得るようにし、前記液滴
受手段には何らのエネルギをも供給しなくてもす
むものであるから、溶融金属のたまり部が非常に
少なくかつ浅いものとなる。このため、従来のプ
ラズマアーク溶解炉（例えば第１図）あるいは真
空アーク溶解炉の場合のように本発明の場合より
も溶融金属量が多くかつ深く溶融金属のたまり部
が形成される方法に比較して、得られた凝固金属
は均一緻密で且つ微細な結晶組織を有し、マクロ
偏析の著しく少ないものであり、たとえば多種類
の合金成分を含む高級金属においてもその加工性
が著しく優れたものであり、適宜の形状に直接鋳
造加工することもでき、加工の自由度が著しく高
い凝固金属塊を得ることができる。また、供給し
たエネルギのほとんどは被溶解材の溶解にのみ消
費され、溶解速度も速いという著しくすぐれた効
果を有している。(Effect of the invention) As explained above, according to this invention,
The tip of a plasma torch connected to one side of the power supply,
A plasma arc is generated between the plasma torch and the material to be melted by facing the end of the material to be melted connected to the other side of the power source, and the material to be melted is melted by the heating by the plasma arc and becomes a liquid. A uniform and fine equiaxed crystal solidified metal or unidirectionally solidified metal is obtained by falling as droplets and receiving them by an appropriate droplet receiving means, and the droplet receiving means is not supplied with any energy. Since there is no need to supply molten metal, the pool of molten metal becomes very small and shallow. For this reason, compared to the method in which the amount of molten metal is larger and the pool of molten metal is formed deeper than in the case of the present invention, as in the case of a conventional plasma arc melting furnace (for example, Fig. 1) or a vacuum arc melting furnace, The obtained solidified metal has a uniform, dense and fine crystal structure, and has extremely little macro segregation, and has excellent workability even in high-grade metals containing many types of alloy components. It is also possible to directly cast it into an appropriate shape, and it is possible to obtain a solidified metal ingot with a significantly high degree of freedom in processing. Further, most of the supplied energy is consumed only for melting the material to be melted, and the melting speed is also fast, which is an extremely excellent effect.
ところで、従来より活用されている真空アーク
溶解炉等においては、偏析の発生しやすい高炭素
鋼、超合金などを溶解するに際し、偏析防止のた
めに入力を抑えて低速溶解を行うのが一般的であ
るが、この発明によればこのような材料であつて
も高速で溶解することが可能である。さらに、真
空アーク溶解法、エレクトロスラグ溶解法、プラ
ズマアーク溶解法（第１図）で大型の鋳塊を製造
しようとした場合、溶融金属のたまり部がかなり
大きく且つ深いため、偏析の発生を防止すること
が著しく困難であつた。これに対してこの発明に
よれば上記溶融金属のたまり部が小さくかつ浅い
ため、大型の鋳塊であつても偏析のない健全なも
のが容易に得られる。加えて、この発明は、大型
の鋳塊を製造するに際して必ずしも太径の被溶解
材を準備しなくともよく、被溶解材の製造および
取扱いが容易であると共に、プラズマトーチの本
数も任意で選ぶことが可能であるため、鋳塊の大
型化は著しく容易である。 By the way, when melting materials such as high carbon steel and superalloys that are prone to segregation in conventional vacuum arc melting furnaces, it is common to reduce input power and perform slow melting to prevent segregation. However, according to the present invention, even such materials can be melted at high speed. Furthermore, when attempting to manufacture large ingots using vacuum arc melting, electroslag melting, or plasma arc melting (Fig. 1), the pool of molten metal is quite large and deep, which prevents segregation from occurring. It was extremely difficult to do so. On the other hand, according to the present invention, since the pool of molten metal is small and shallow, a healthy ingot without segregation can be easily obtained even if it is a large ingot. In addition, the present invention does not necessarily require preparing a large diameter material to be melted when producing a large ingot, making it easy to manufacture and handle the material to be melted, and allowing the number of plasma torches to be selected arbitrarily. Therefore, it is extremely easy to increase the size of the ingot.
このように、この発明は、従来技術の問題解決
にとつて著しく有効な手段を提供するものであ
り、その効果には絶大なものがある。 As described above, the present invention provides an extremely effective means for solving the problems of the prior art, and its effects are enormous.
第１図は従来のプラズマアーク溶解装置の一例
を示す断面説明図、第２図、第３図および第４図
はいずれもこの発明の実施例によるプラズマアー
ク溶解装置の断面説明図、第５図は試験結果を示
すグラフである。
１１……密閉容器、１２……プラズマトーチ、
１３……プラズマトーチ保持手段、１４……被溶
解材、１５……被溶解材保持手段、１６……るつ
ぼ（液滴受手段）、１７……るつぼ回転手段、１
８……プラズマアーク発生用電源、１９……プラ
ズマアーク、２０……液滴、２１……凝固金属。
FIG. 1 is a cross-sectional explanatory diagram showing an example of a conventional plasma arc melting apparatus, FIGS. 2, 3, and 4 are all cross-sectional explanatory diagrams of a plasma arc melting apparatus according to an embodiment of the present invention, and FIG. is a graph showing the test results. 11...Airtight container, 12...Plasma torch,
13... Plasma torch holding means, 14... Material to be melted, 15... Material holding means to be melted, 16... Crucible (droplet receiving means), 17... Crucible rotation means, 1
8... Power source for plasma arc generation, 19... Plasma arc, 20... Droplet, 21... Solidified metal.
Claims (1)
と、前記電源の他方に接続した被溶解材の端部と
を対向させて前記プラズマトーチと被溶解材との
間でプラズマアークを発生させ、前記プラズマア
ークによる加熱で前記被溶解材を溶解して落下さ
せ、次いで凝固させて均一で且つ微細な等軸晶凝
固金属あるいは一方向凝固金属を得ることを特徴
とするプラズマアーク溶解方法。 ２ プラズマアーク発生用電源と、前記電源の一
方に接続したプラズマトーチと、前記電源の他方
に接続した被溶解材の端部と前記プラズマトーチ
の先端とを対向させた状態で前記被溶解材を保持
する被溶解材保持手段と、前記プラズマトーチと
被溶解材との間で発生したプラズマアークにより
加熱された被溶解材の液滴を受ける液滴受手段
と、を備えたことを特徴とするプラズマアーク溶
解装置。[Scope of Claims] 1. Plasma arc is created between the plasma torch and the material to be melted by making the tip of the plasma torch connected to one of the power sources and the end of the material to be melted connected to the other power source face each other. Plasma arc melting is characterized in that the material to be melted is melted by heating by the plasma arc, allowed to fall, and then solidified to obtain a uniform and fine equiaxed crystal solidified metal or unidirectionally solidified metal. Method. 2. A power source for plasma arc generation, a plasma torch connected to one of the power sources, and the material to be melted with the end of the material connected to the other power source facing the tip of the plasma torch. The method is characterized by comprising a means for holding the material to be melted, and a droplet receiving means for receiving droplets of the material to be melted heated by the plasma arc generated between the plasma torch and the material to be melted. Plasma arc melting equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19976683A JPS6092432A (en) | 1983-10-24 | 1983-10-24 | Method and device for plasma arc melting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19976683A JPS6092432A (en) | 1983-10-24 | 1983-10-24 | Method and device for plasma arc melting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6092432A JPS6092432A (en) | 1985-05-24 |
| JPH0413410B2 true JPH0413410B2 (en) | 1992-03-09 |
Family
ID=16413259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19976683A Granted JPS6092432A (en) | 1983-10-24 | 1983-10-24 | Method and device for plasma arc melting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6092432A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002333285A (en) * | 2001-05-10 | 2002-11-22 | Ryoda Sato | Melting method using plasma arc and plasma arc melting furnace |
| JP4704797B2 (en) * | 2005-04-15 | 2011-06-22 | 株式会社神戸製鋼所 | Method for producing long ingot of active refractory metal-containing alloy by plasma arc melting |
| JP2017003337A (en) * | 2015-06-08 | 2017-01-05 | 大同特殊鋼株式会社 | Wettability test device |
-
1983
- 1983-10-24 JP JP19976683A patent/JPS6092432A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6092432A (en) | 1985-05-24 |
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