JP6830379B2

JP6830379B2 - Plasma torch and plasma generation method

Info

Publication number: JP6830379B2
Application number: JP2017042970A
Authority: JP
Inventors: 浩規前川
Original assignee: Nippon Steel Engineering Co Ltd
Current assignee: Nippon Steel Engineering Co Ltd
Priority date: 2017-03-07
Filing date: 2017-03-07
Publication date: 2021-02-17
Anticipated expiration: 2037-03-07
Also published as: JP2018144081A

Description

本発明は、プラズマトーチ及びプラズマ発生方法に関する。 The present invention relates to a plasma torch and a plasma generation method.

例えば連続鋳造において、溶融した液状の金属（溶湯）の温度を制御するために、プラズマトーチを用いたプラズマ加熱方式が知られている。プラズマトーチを用いてプラズマを発生させる方法としては、プラズマトーチに所定の電圧を印加した状態で、（１）プラズマトーチを溶湯に近接させる方法（第１の方法）や、（２）プラズマトーチを溶湯に浸漬し、プラズマトーチを溶湯から引き上げる方法（第２の方法）が挙げられる。第１の方法によれば、プラズマトーチが溶湯と接触しないようにプラズマトーチの先端と溶湯の表面とのギャップを極めて精度よく制御する必要があるにも関わらず、プラズマが発生しない場合がある。そこで、プラズマを１００％の確率で発生させることが可能な第２の方法の採用が検討されている。 For example, in continuous casting, a plasma heating method using a plasma torch is known in order to control the temperature of a molten liquid metal (molten metal). As a method of generating plasma using a plasma torch, (1) a method of bringing the plasma torch close to the molten metal (first method) or (2) a plasma torch with a predetermined voltage applied to the plasma torch. A method of immersing the plasma torch in the molten metal and pulling the plasma torch out of the molten metal (second method) can be mentioned. According to the first method, plasma may not be generated even though the gap between the tip of the plasma torch and the surface of the molten metal needs to be controlled extremely accurately so that the plasma torch does not come into contact with the molten metal. Therefore, the adoption of a second method capable of generating plasma with a 100% probability is being considered.

ところが、金属製のプラズマトーチを用いる場合、プラズマトーチが溶湯と接触することにより溶湯の熱を奪ってしまい、溶湯の温度制御が困難となる傾向にある。そこで、特許文献１は、プラズマトーチの少なくとも先端を黒鉛製とすることを開示している。 However, when a metal plasma torch is used, the plasma torch comes into contact with the molten metal and takes away the heat of the molten metal, which tends to make it difficult to control the temperature of the molten metal. Therefore, Patent Document 1 discloses that at least the tip of the plasma torch is made of graphite.

特開２００１−０３３１７２号公報Japanese Unexamined Patent Publication No. 2001-033172

しかしながら、プラズマの発生のために黒鉛製のプラズマトーチを溶湯に浸漬すると、プラズマトーチを溶湯に浸漬しないでプラズマを発生させる第１の方法と比較して、プラズマトーチが極めて損耗しやすく、プラズマトーチの寿命が１／３〜１／２程度となってしまう。 However, when a graphite plasma torch is immersed in a molten metal to generate plasma, the plasma torch is extremely easily worn as compared with the first method of generating plasma without immersing the plasma torch in the molten metal, and the plasma torch The life of the plasma is about 1/3 to 1/2.

そこで、本発明は、長寿命化を図ることが可能なプラズマトーチ及びプラズマ発生方法を提供する。 Therefore, the present invention provides a plasma torch and a plasma generation method capable of extending the service life.

本発明の一つの観点に係るプラズマトーチは、黒鉛製のトーチ本体と、トーチ本体の先端よりも外方に突出するようにトーチ本体の先端部に取り付けられた導電性部材とを備える。 A plasma torch according to one aspect of the present invention includes a graphite torch body and a conductive member attached to the tip of the torch body so as to project outward from the tip of the torch body.

本発明の一つの観点に係るプラズマトーチでは、トーチ本体の先端よりも外方に突出するように導電性部材がトーチ本体の先端部に取り付けられている。そのため、プラズマトーチが溶湯に向けて降下していくと、導電性部材が溶湯に接触し、黒鉛製のトーチ本体は溶湯に接触しないか、ほとんど接触しない。従って、導電性部材が溶湯に接触することで確実にプラズマを発生させることができると共に、トーチ本体が溶湯に浸漬され難いのでプラズマトーチ（トーチ本体）の長寿命化を図ることが可能となる。 In the plasma torch according to one aspect of the present invention, a conductive member is attached to the tip of the torch body so as to project outward from the tip of the torch body. Therefore, when the plasma torch descends toward the molten metal, the conductive member comes into contact with the molten metal, and the graphite torch body does not or hardly contacts the molten metal. Therefore, plasma can be reliably generated when the conductive member comes into contact with the molten metal, and the torch body is less likely to be immersed in the molten metal, so that the life of the plasma torch (torch body) can be extended.

導電性部材の電気伝導率は、トーチ本体の電気伝導率以上であってもよい。この場合、トーチ本体に所定の電圧を印加すると、導電性部材にも当該電圧が印加されやすくなるので、導電性部材を溶湯に浸漬することでより確実に導電性部材と溶湯との間にプラズマを発生させることができる。 The electric conductivity of the conductive member may be equal to or higher than the electric conductivity of the torch body. In this case, when a predetermined voltage is applied to the torch body, the voltage is likely to be applied to the conductive member as well. Therefore, by immersing the conductive member in the molten metal, plasma can be more reliably applied between the conductive member and the molten metal. Can be generated.

導電性部材は金属又は黒鉛によって構成されてもよい。 The conductive member may be made of metal or graphite.

トーチ本体の先端部には開口部が設けられており、導電性部材は開口部に挿嵌されていてもよい。この場合、導電性部材のトーチ本体への取り付けを極めて簡便に行える。 An opening is provided at the tip of the torch body, and the conductive member may be inserted into the opening. In this case, the conductive member can be attached to the torch body very easily.

トーチ本体の先端部には複数の開口部が設けられており、導電性部材は複数の開口部の少なくともいずれか一つに挿嵌されていてもよい。この場合、導電性部材のトーチ本体への取り付けを極めて簡便に行える。加えて、トーチ本体の先端部には複数の開口部が設けられているので、溶湯がトーチ本体の先端部に飛び跳ねたり、スラグがトーチ本体の先端部に付着して、開口部のいずれかが閉塞されても、閉塞されていない他の開口部に導電性部材を挿嵌させることができる。 A plurality of openings are provided at the tip of the torch body, and the conductive member may be inserted into at least one of the plurality of openings. In this case, the conductive member can be attached to the torch body very easily. In addition, since the tip of the torch body is provided with a plurality of openings, the molten metal may jump to the tip of the torch body, or slag may adhere to the tip of the torch body, causing any of the openings. Even if it is closed, the conductive member can be inserted into another opening that is not closed.

導電性部材を保持する保持具をさらに備え、保持具は、トーチ本体の先端部に着脱可能に嵌着するように構成されていてもよい。この場合、導電性部材のトーチ本体への取り付けを極めて簡便に行える。 A holder for holding the conductive member may be further provided, and the holder may be configured to be detachably fitted to the tip of the torch body. In this case, the conductive member can be attached to the torch body very easily.

導電性部材は、トーチ本体の先端部の外周に嵌着可能な開口部を有してもよい。この場合、導電性部材のトーチ本体への取り付けを極めて簡便に行える。 The conductive member may have an opening that can be fitted to the outer periphery of the tip end portion of the torch body. In this case, the conductive member can be attached to the torch body very easily.

本発明の他の観点に係るプラズマ発生方法は、上記のプラズマトーチと溶湯との間にプラズマを発生する方法であって、トーチ本体に所定の電圧を印加した状態で、導電性部材を溶湯に接触させる第１の工程と、第１の工程の後に、導電性部材を溶湯の外に引き上げる第２の工程とを含む。 The plasma generation method according to another aspect of the present invention is a method of generating plasma between the plasma torch and the molten metal, and the conductive member is made into the molten metal while a predetermined voltage is applied to the torch body. It includes a first step of contacting and, after the first step, a second step of pulling the conductive member out of the molten metal.

本発明の他の観点に係るプラズマ発生方法では、第１の工程において導電性部材を溶湯に浸漬し、続く第２の工程において導電性部材を溶湯の外に引き上げている。そのため、黒鉛製のトーチ本体は溶湯に接触しないか、ほとんど接触しない。従って、導電性部材が溶湯に接触することで確実にプラズマを発生させることができると共に、トーチ本体が溶湯に浸漬されないのでトーチ本体の長寿命化を図ることが可能となる。 In the plasma generation method according to another aspect of the present invention, the conductive member is immersed in the molten metal in the first step, and the conductive member is pulled out of the molten metal in the subsequent second step. Therefore, the graphite torch body does not come into contact with or hardly comes into contact with the molten metal. Therefore, plasma can be reliably generated when the conductive member comes into contact with the molten metal, and the torch body is not immersed in the molten metal, so that the life of the torch body can be extended.

本発明に係るプラズマトーチ及びプラズマ発生方法によれば、プラズマトーチの長寿命化を図ることが可能となる。 According to the plasma torch and the plasma generation method according to the present invention, it is possible to extend the life of the plasma torch.

図１は、連続鋳造装置の一つの例を示す図である。FIG. 1 is a diagram showing an example of a continuous casting apparatus. 図２はプラズマトーチの一つの例を示す図であり、図２の（ａ）はプラズマトーチの断面を示し、図２の（ｂ）はトーチ本体の端面を示す。2A and 2B are views showing one example of a plasma torch, FIG. 2A shows a cross section of the plasma torch, and FIG. 2B shows an end face of the torch body. 図３はプラズマトーチの他の例を示す図であり、図３の（ａ）はプラズマトーチの側面を示し、図３の（ｂ）は図３の（ａ）のＢ−Ｂ線断面を示す。3A and 3B are views showing another example of the plasma torch, FIG. 3A shows a side surface of the plasma torch, and FIG. 3B shows a cross section taken along line BB of FIG. 3A. .. 図４は、プラズマトーチの他の例を示す図である。FIG. 4 is a diagram showing another example of the plasma torch.

以下に説明される本発明に係る実施形態は本発明を説明するための例示であるので、本発明は以下の内容に限定されるべきではない。以下の説明において、同一要素又は同一機能を有する要素には同一符号を用いることとし、重複する説明は省略する。 Since the embodiments according to the present invention described below are examples for explaining the present invention, the present invention should not be limited to the following contents. In the following description, the same reference numerals will be used for the same elements or elements having the same function, and duplicate description will be omitted.

まず、図１を参照して、連続鋳造装置１００の構成について説明する。連続鋳造装置１００は、取鍋１０１と、タンディッシュ１０２と、鋳型１０３と、鋳片支持ロール１０４と、プラズマ発生装置１を備える。 First, the configuration of the continuous casting apparatus 100 will be described with reference to FIG. The continuous casting apparatus 100 includes a ladle 101, a tundish 102, a mold 103, a slab support roll 104, and a plasma generator 1.

取鍋１０１は、溶湯（溶鋼）Ｍを貯留する容器である。タンディッシュ１０２は、取鍋１０１の下方に配置されている。タンディッシュ１０２は、取鍋１０１の底壁に設けられたノズル１０１ａから流出した溶湯Ｍを貯留する容器である。鋳型１０３は、タンディッシュ１０２の下方に配置されている。鋳型１０３は、タンディッシュ１０２の底壁に設けられたノズル１０２ａから流出した溶湯を冷却しながら所定形状に成形する。鋳片支持ロール１０４は、鋳型１０３から引き抜かれた鋳片Ｓを冷却しつつ搬送する。 The ladle 101 is a container for storing the molten metal (molten steel) M. The tundish 102 is arranged below the ladle 101. The tundish 102 is a container for storing the molten metal M flowing out from the nozzle 101a provided on the bottom wall of the ladle 101. The mold 103 is located below the tundish 102. The mold 103 is formed into a predetermined shape while cooling the molten metal flowing out from the nozzle 102a provided on the bottom wall of the tundish 102. The slab support roll 104 conveys the slab S drawn from the mold 103 while cooling it.

プラズマ発生装置１は、タンディッシュ１０２内の溶湯Ｍの温度を制御するための装置である。プラズマ発生装置１は、プラズマトーチ１０と、トーチ保持具１２と、昇降機１４とを備える。 The plasma generator 1 is a device for controlling the temperature of the molten metal M in the tundish 102. The plasma generator 1 includes a plasma torch 10, a torch holder 12, and an elevator 14.

プラズマトーチ１０は、黒鉛によって構成されたトーチ本体１６と、導電性部材１８とを有する。 The plasma torch 10 has a torch body 16 made of graphite and a conductive member 18.

トーチ本体１６は、例えば直線状に延びる丸棒である。トーチ本体１６の直径は、例えば１００ｍｍ〜２００ｍｍ程度であってもよい。トーチ本体１６の長さは、例えば１０００ｍｍ〜２５００ｍｍ程度であってもよい。トーチ本体１６の形状は、丸形以外の他の形状であってもよいし、必ずしも直線状に延びておらず屈曲していてもよい。トーチ本体１６は、図示しない電源に接続されており、所定の電圧（例えば１００Ｖ〜５００Ｖ程度）が印加される。 The torch body 16 is, for example, a round bar extending linearly. The diameter of the torch body 16 may be, for example, about 100 mm to 200 mm. The length of the torch body 16 may be, for example, about 1000 mm to 2500 mm. The shape of the torch body 16 may be a shape other than the round shape, or may not necessarily extend linearly but may be bent. The torch body 16 is connected to a power source (not shown), and a predetermined voltage (for example, about 100V to 500V) is applied.

トーチ本体１６には、図２の（ａ）及び（ｂ）に示されるように、その長手方向に延びる複数の貫通孔１６ａ，１６ｂが形成されている。そのため、トーチ本体１６の端面には、貫通孔１６ａ，１６ｂからなる開口部が生じている。各貫通孔１６ａ，１６ｂの直径は、例えば５ｍｍ〜１０ｍｍ程度であってもよい。貫通孔１６ａは、トーチ本体１６の中心部に配置されている。貫通孔１６ａは、プラズマを発生させるための動作ガス（例えば、アルゴン、窒素等の不活性ガス）の供給路として機能する。貫通孔１６ｂは、トーチ本体１６の周縁に沿うように貫通孔１６ａ周りに配置されている。貫通孔１６ｂは、トーチ本体１６の先端部Ｔに導電性部材１８を取り付けるための保持孔として機能する。 As shown in FIGS. 2A and 2B, the torch body 16 is formed with a plurality of through holes 16a and 16b extending in the longitudinal direction thereof. Therefore, an opening made of through holes 16a and 16b is formed on the end surface of the torch body 16. The diameter of each of the through holes 16a and 16b may be, for example, about 5 mm to 10 mm. The through hole 16a is arranged at the center of the torch body 16. The through hole 16a functions as a supply path for an operating gas (for example, an inert gas such as argon or nitrogen) for generating plasma. The through hole 16b is arranged around the through hole 16a so as to be along the peripheral edge of the torch body 16. The through hole 16b functions as a holding hole for attaching the conductive member 18 to the tip portion T of the torch body 16.

導電性部材１８は、図１及び図２に示されるように、トーチ本体１６の先端よりも外方に突出するようにトーチ本体１６の先端部Ｔに取り付けられている。導電性部材１８の材料としては、例えば、金属又は黒鉛が挙げられる。導電性部材１８を構成する金属材料としては、例えば、鉄、アルミニウム、銅などが挙げられる。導電性部材１８の電気伝導率は、トーチ本体１６の電気伝導率、すなわち黒鉛の電気伝導率（１．６×１０^−５Ｓ／ｃｍ程度）以上であってもよい。この場合、トーチ本体１６に所定の電圧を印加すると、導電性部材１８にも当該電圧が印加されやすくなるので、導電性部材１８を溶湯Ｍに浸漬することでより確実に導電性部材１８と溶湯Ｍとの間にプラズマを発生させることができる。 As shown in FIGS. 1 and 2, the conductive member 18 is attached to the tip portion T of the torch main body 16 so as to project outward from the tip of the torch main body 16. Examples of the material of the conductive member 18 include metal and graphite. Examples of the metal material constituting the conductive member 18 include iron, aluminum, and copper. The electric conductivity of the conductive member 18 may be equal to or higher than the electric conductivity of the torch main body 16, that is, the electric conductivity of graphite (about 1.6 × ^10-5 S / cm). In this case, when a predetermined voltage is applied to the torch body 16, the voltage is likely to be applied to the conductive member 18, so that by immersing the conductive member 18 in the molten metal M, the conductive member 18 and the molten metal 18 can be more reliably applied. Plasma can be generated between M and M.

導電性部材１８は、図２の（ａ）に示されるように、トーチ本体１６に取り付けられる側の端部である基端部１８ａと、溶湯Ｍに浸漬される側の端部である先端部１８ｂとを有する。基端部１８ａは、截頭円錐形状を呈している。基端部１８ａの端面側の直径は貫通孔１６ｂの直径よりも小さく、基端部１８ａの先端部１８ｂ側の直径は、貫通孔１６ｂの直径よりも大きい。そのため、基端部１８ａを貫通孔１６ｂに押し込むことにより、導電性部材１８（基端部１８ａ）を貫通孔１６ｂに挿嵌することができる。先端部１８ｂは、円柱形状を呈している。先端部１８ｂの直径は、例えば１０ｍｍ程度であってもよい。導電性部材１８の全長は、例えば２００ｍｍ程度であってもよい。 As shown in FIG. 2A, the conductive member 18 has a base end portion 18a, which is an end portion on the side attached to the torch body 16, and a tip portion, which is an end portion on the side immersed in the molten metal M. Has 18b and. The base end portion 18a has a conical shape. The diameter of the base end portion 18a on the end face side is smaller than the diameter of the through hole 16b, and the diameter of the base end portion 18a on the tip end portion 18b side is larger than the diameter of the through hole 16b. Therefore, the conductive member 18 (base end portion 18a) can be inserted into the through hole 16b by pushing the base end portion 18a into the through hole 16b. The tip portion 18b has a cylindrical shape. The diameter of the tip portion 18b may be, for example, about 10 mm. The total length of the conductive member 18 may be, for example, about 200 mm.

成分を厳密に一定に保つことが求められている溶湯Ｍの場合には、導電性部材１８の全てが溶融して溶湯Ｍに溶け込んだ際に溶湯Ｍに生じさせる成分変動が許容可能な程度の成分量を導電性部材１８が含有していてもよい。例えば、導電性部材１８が単一の成分からなる場合には、導電性部材１８の大きさ（体積）を所定値以下としてもよい。 In the case of the molten metal M, which is required to keep the components strictly constant, the component fluctuation caused in the molten metal M when all of the conductive members 18 are melted and dissolved in the molten metal M is acceptable. The conductive member 18 may contain the amount of the component. For example, when the conductive member 18 is composed of a single component, the size (volume) of the conductive member 18 may be set to a predetermined value or less.

図１に戻って、トーチ保持具１２は、トーチ本体１６の上端部を保持する。昇降機１４は、トーチ保持具１２を上下方向に昇降させる。そのため、トーチ保持具１２によって保持されているトーチ本体１６（プラズマトーチ１０）も、昇降機１４によって上下方向に昇降され、タンディッシュ１０２内の溶湯Ｍに対して近接及び離間する。 Returning to FIG. 1, the torch holder 12 holds the upper end portion of the torch body 16. The elevator 14 raises and lowers the torch holder 12 in the vertical direction. Therefore, the torch body 16 (plasma torch 10) held by the torch holder 12 is also moved up and down in the vertical direction by the elevator 14, and is brought close to and separated from the molten metal M in the tundish 102.

プラズマ発生装置１によってプラズマを発生させる場合には、まず、プラズマトーチ１０の先端部の周囲（溶湯Ｍの湯面近傍）を動作ガス雰囲気とする。動作ガス雰囲気とするためには、貫通孔１６ａから動作ガスを噴出させてもよいし、他のガス源から動作ガスを供給してもよい。 When plasma is generated by the plasma generator 1, first, the periphery of the tip of the plasma torch 10 (near the surface of the molten metal M) is set as the operating gas atmosphere. In order to create an operating gas atmosphere, the operating gas may be ejected from the through hole 16a, or the operating gas may be supplied from another gas source.

次に、トーチ本体１６に所定の電圧を印加させる。そして、この状態で、昇降機１４によってプラズマトーチ１０を溶湯Ｍに向けて降下させ、トーチ本体１６が溶湯Ｍに接触しないように、導電性部材１８を溶湯Ｍに接触（浸漬）させる。次に、昇降機１４によってプラズマトーチ１０（導電性部材１８）が溶湯Ｍから離間するように、プラズマトーチ１０を上昇させる。そうすると、導電性部材１８と溶湯Ｍとの間に間隙（ギャップ）が生ずる瞬間に絶縁破壊が生じ、導電性部材１８と溶湯Ｍとの間に電流が流れる。これにより、導電性部材１８と溶湯Ｍとの間にプラズマが発生する。その後は、導電性部材１８が熱により徐々に消耗していき、導電性部材１８が消滅する直前近傍において、トーチ本体１６と溶湯Ｍとの間でプラズマが維持される。その後、トーチ本体１６は、熱によって徐々に消耗していく。 Next, a predetermined voltage is applied to the torch body 16. Then, in this state, the plasma torch 10 is lowered toward the molten metal M by the elevator 14, and the conductive member 18 is brought into contact with (immerse) the molten metal M so that the torch body 16 does not come into contact with the molten metal M. Next, the elevator 14 raises the plasma torch 10 so that the plasma torch 10 (conductive member 18) is separated from the molten metal M. Then, dielectric breakdown occurs at the moment when a gap is formed between the conductive member 18 and the molten metal M, and a current flows between the conductive member 18 and the molten metal M. As a result, plasma is generated between the conductive member 18 and the molten metal M. After that, the conductive member 18 is gradually consumed by heat, and plasma is maintained between the torch body 16 and the molten metal M in the vicinity immediately before the conductive member 18 disappears. After that, the torch body 16 is gradually consumed by heat.

以上のような本実施形態では、トーチ本体１６の先端よりも外方に突出するように導電性部材１８がトーチ本体１６の先端部Ｔに取り付けられている。そのため、プラズマトーチ１０が溶湯Ｍに向けて降下していくと、導電性部材１８が溶湯Ｍに接触し、黒鉛製のトーチ本体１６は溶湯Ｍに接触しないか、ほとんど接触しない。従って、導電性部材１８が溶湯Ｍに接触することで確実にプラズマを発生させることができると共に、トーチ本体１６が溶湯Ｍに浸漬され難いのでプラズマトーチ１０（トーチ本体１６）の長寿命化を図ることが可能となる。 In the present embodiment as described above, the conductive member 18 is attached to the tip portion T of the torch main body 16 so as to project outward from the tip of the torch main body 16. Therefore, when the plasma torch 10 descends toward the molten metal M, the conductive member 18 comes into contact with the molten metal M, and the graphite torch body 16 does not or hardly contacts the molten metal M. Therefore, when the conductive member 18 comes into contact with the molten metal M, plasma can be reliably generated, and the torch body 16 is difficult to be immersed in the molten metal M, so that the life of the plasma torch 10 (torch body 16) is extended. It becomes possible.

本実施形態では、トーチ本体１６に設けられている貫通孔１６ｂに導電性部材１８が挿嵌されている。そのため、導電性部材１８のトーチ本体１６への取り付けを極めて簡便に行える。 In the present embodiment, the conductive member 18 is inserted into the through hole 16b provided in the torch body 16. Therefore, the conductive member 18 can be attached to the torch body 16 very easily.

本実施形態では、トーチ本体１６に複数の貫通孔１６ｂが設けられており、導電性部材１８が複数の貫通孔１６ｂのいずれか一つに挿嵌されている。そのため、溶湯Ｍがトーチ本体１６の先端部Ｔに飛び跳ねたり、スラグがトーチ本体１６の先端部Ｔに付着して、貫通孔１６ｂのいずれかが閉塞されても、閉塞されていない他の貫通孔１６ｂに導電性部材１８を挿嵌させることができる。 In the present embodiment, the torch body 16 is provided with a plurality of through holes 16b, and the conductive member 18 is inserted into any one of the plurality of through holes 16b. Therefore, even if the molten metal M jumps to the tip T of the torch body 16 or the slag adheres to the tip T of the torch body 16 and any of the through holes 16b is blocked, the other through holes that are not blocked. The conductive member 18 can be inserted into 16b.

以上、本発明に係る実施形態について詳細に説明したが、本発明の要旨の範囲内で種々の変形を上記の実施形態に加えてもよい。例えば、貫通孔１６ｂに代えて、トーチ本体１６を貫通しない凹部がトーチ本体１６の端面に形成されていてもよい。いずれにしても、導電性部材１８が挿嵌可能な開口部がトーチ本体１６の端面に設けられていればよい。 Although the embodiments according to the present invention have been described in detail above, various modifications may be added to the above embodiments within the scope of the gist of the present invention. For example, instead of the through hole 16b, a recess that does not penetrate the torch body 16 may be formed on the end surface of the torch body 16. In any case, an opening into which the conductive member 18 can be inserted may be provided on the end face of the torch body 16.

図３に示されるように、導電性部材１８を保持する保持具２０を介して、導電性部材１８をトーチ本体１６の先端部Ｔに取り付けてもよい。具体的には、トーチ本体１６の周面には、図３の（ａ）に示されるように、トーチ本体１６の長さ方向において所定の間隔を有するように複数の環状凹部１６ｃが形成されている。保持具２０は、環状凹部１６ｃに着脱可能に構成されている。すなわち、保持具２０は、図３の（ｂ）に示されるように、導電性部材１８を保持可能なベース部２０ａと、ベース部２０ａに対して旋回可能な一対の可動部２０ｂとを有する。 As shown in FIG. 3, the conductive member 18 may be attached to the tip portion T of the torch body 16 via a holder 20 that holds the conductive member 18. Specifically, as shown in FIG. 3A, a plurality of annular recesses 16c are formed on the peripheral surface of the torch body 16 so as to have a predetermined interval in the length direction of the torch body 16. There is. The holder 20 is configured to be removable from the annular recess 16c. That is, as shown in FIG. 3B, the holder 20 has a base portion 20a capable of holding the conductive member 18 and a pair of movable portions 20b that can be swiveled with respect to the base portion 20a.

保持具２０は、一対の可動部２０ｂの各先端部が係合した状態において環状凹部１６ｃに嵌着し、一対の可動部２０ｂの各先端部が離間した状態において環状凹部１６ｃから取り外される。このように、保持具２０を用いて導電性部材１８をトーチ本体１６に取り付けるようにすると、導電性部材１８のトーチ本体１６への取り付けを極めて簡便に行える。トーチ本体１６の消耗の程度に応じて、トーチ本体１６の最も先端側に位置する環状凹部１６ｃに保持具２０を取り付けてもよい。 The holder 20 is fitted into the annular recess 16c when the tips of the pair of movable portions 20b are engaged, and is removed from the annular recess 16c when the tips of the pair of movable portions 20b are separated from each other. In this way, when the conductive member 18 is attached to the torch body 16 by using the holder 20, the conductive member 18 can be attached to the torch body 16 extremely easily. Depending on the degree of wear of the torch body 16, the holder 20 may be attached to the annular recess 16c located at the most distal end side of the torch body 16.

図４に示されるように、導電性部材１８がトーチ本体１６の先端部Ｔの外周に嵌着可能に構成されていてもよい。具体的には、導電性部材１８は半球殻状を呈しており、その開放端側の開口部１８ｃがトーチ本体１６の先端部Ｔの外周に嵌着可能に構成されている。すなわち、開口部１８ｃの内径は、トーチ本体１６の外径よりも若干大きく設定されている。この場合も、導電性部材１８のトーチ本体１６への取り付けを極めて簡便に行える。導電性部材１８には、貫通孔１６ａからの動作ガスが通過可能な貫通孔１８ｄが設けられている。図４において、貫通孔１８ｄは導電性部材１８の頂部に位置しているが、貫通孔１６ａからの動作ガスが通過可能であれば貫通孔１８ｄの位置は特に限定されない。なお、開口部１８ｃを有していれば導電性部材１８は半球殻状以外の他の形状（例えば、筒状）を呈していてもよい。 As shown in FIG. 4, the conductive member 18 may be configured to be fitable on the outer periphery of the tip portion T of the torch body 16. Specifically, the conductive member 18 has a hemispherical shell shape, and the opening 18c on the open end side thereof is configured to be fitable to the outer periphery of the tip portion T of the torch body 16. That is, the inner diameter of the opening 18c is set to be slightly larger than the outer diameter of the torch body 16. Also in this case, the conductive member 18 can be attached to the torch body 16 very easily. The conductive member 18 is provided with a through hole 18d through which the operating gas from the through hole 16a can pass. In FIG. 4, the through hole 18d is located at the top of the conductive member 18, but the position of the through hole 18d is not particularly limited as long as the operating gas from the through hole 16a can pass through. The conductive member 18 may have a shape other than the hemispherical shell shape (for example, a tubular shape) as long as it has the opening 18c.

１…プラズマ発生装置、１０…プラズマトーチ、１２…トーチ保持具、１４…昇降機、１６…トーチ本体、１６ａ，１６ｂ…貫通孔（開口部）、１６ｃ…環状凹部、１８…導電性部材、１８ａ…基端部、１８ｂ…先端部、１８ｃ…開口部、１８ｄ…貫通孔、２０…保持具、２０ａ…ベース部、２０ｂ…可動部、１００…連続鋳造装置、１０１…取鍋、１０１ａ…ノズル、１０２…タンディッシュ、１０２ａ…ノズル、１０３…鋳型、１０４…鋳片支持ロール、Ｍ…溶湯（溶鋼）、Ｓ…鋳片、Ｔ…先端部。 1 ... Plasma generator, 10 ... Plasma torch, 12 ... Torch holder, 14 ... Elevator, 16 ... Torch body, 16a, 16b ... Through holes (openings), 16c ... Annular recess, 18 ... Conductive member, 18a ... Base end, 18b ... Tip, 18c ... Opening, 18d ... Through hole, 20 ... Holder, 20a ... Base, 20b ... Movable, 100 ... Continuous casting device, 101 ... Ladle, 101a ... Nozzle, 102 ... Tandish, 102a ... Nozzle, 103 ... Mold, 104 ... Shard support roll, M ... Molten metal (molten steel), S ... Shard, T ... Tip.

Claims

Graphite torch body and
A metal conductive member attached to the tip of the torch body so as to protrude outward from the tip of the torch body is provided .
An opening is provided at the tip of the torch body.
The conductive member that is fitted into the opening, the plasma torch.

Graphite torch body and
A metal conductive member attached to the tip of the torch body so as to protrude outward from the tip of the torch body is provided.
A plurality of openings are provided at the tip of the torch body.
A plasma torch in which the conductive member is inserted into at least one of the plurality of openings.

Graphite torch body and
A metal conductive member attached to the tip of the torch body so as to project outward from the tip of the torch body.
A holder for holding the conductive member is provided.
The holding tool is a plasma torch that is configured to be detachably fitted to a tip end portion of the torch body.

Graphite torch body and
A metal conductive member attached to the tip of the torch body so as to project outward from the tip of the torch body.
The conductive member is a plasma torch having an opening that can be fitted to the outer periphery of the tip end portion of the torch body.

Plasma is generated between the torch body made of graphite and the plasma torch provided with the metal conductive member attached to the tip end portion of the torch body so as to project outward from the tip end of the torch body. The way it happens,
The first step of bringing the conductive member into contact with the molten metal while applying a predetermined voltage to the torch body, and
A plasma generation method including a second step of pulling the conductive member out of the molten metal after the first step.

An opening is provided at the tip of the torch body.
The method according to claim 5, wherein the conductive member is inserted into the opening.

A plurality of openings are provided at the tip of the torch body.
The method according to claim 5, wherein the conductive member is inserted into at least one of the plurality of openings.

Further provided with a holder for holding the conductive member,
The method according to claim 5, wherein the holder is configured to be detachably fitted to a tip end portion of the torch body.

The method according to claim 5, wherein the conductive member has an opening that can be fitted on the outer periphery of the tip end portion of the torch body.