JP2001192743A - Method for dissolving titanium or titanium alloy scrap - Google Patents
Method for dissolving titanium or titanium alloy scrapInfo
- Publication number
- JP2001192743A JP2001192743A JP2000255491A JP2000255491A JP2001192743A JP 2001192743 A JP2001192743 A JP 2001192743A JP 2000255491 A JP2000255491 A JP 2000255491A JP 2000255491 A JP2000255491 A JP 2000255491A JP 2001192743 A JP2001192743 A JP 2001192743A
- Authority
- JP
- Japan
- Prior art keywords
- titanium
- scrap
- melting
- titanium alloy
- crucible
- 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.)
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- General Induction Heating (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、チタン又はチタン
合金製スクラップ（以下、Tiスクラップと総称する）の
溶解方法、並びに該溶解方法で溶製された溶湯を鋳造し
て製造される真空アーク炉再溶解法用の電極に関するも
のである。The present invention relates to a method for melting titanium or titanium alloy scrap (hereinafter collectively referred to as Ti scrap), and a vacuum arc furnace manufactured by casting a molten metal produced by the melting method. The present invention relates to an electrode for a remelting method.
【０００２】[0002]
【従来の技術】近年、チタンやチタン合金材料の用途が
様々に広がっており、特にチタンは鉄やアルミニウムに
続き、第三の金属としての需要が見込める金属材料であ
る。このチタンの製造方法については、これまで真空ア
ーク溶解法，電子ビーム溶解法やプラズマ溶解法といっ
た方法が採用されているが、いずれも大量のTiスクラッ
プを一括で溶解できる方法ではなく、今後発生量が増大
すると考えられるTiスクラップを一括して大量に溶解す
ることのできる方法が要望されている。2. Description of the Related Art In recent years, applications of titanium and titanium alloy materials have been variously widespread. In particular, titanium is a metal material expected to be a third metal following iron and aluminum. For the method of producing titanium, methods such as vacuum arc melting, electron beam melting, and plasma melting have been adopted. However, none of these methods is capable of melting a large amount of Ti scrap at once. There is a demand for a method capable of dissolving a large amount of Ti scrap, which is considered to increase the total amount of Ti scrap.
【０００３】例えば、真空アーク炉再溶解法（VAR法）
によってチタンやチタン合金を製造する方法では、介在
物のない均一な組成を有するVAR法用の電極が要望され
ている。しかしながら、従来の方法では、原料が種々の
大きさであることから、電極を製造する際には原料のサ
イズを揃え、更にこれらを溶接しやすくするためにプレ
スを行う必要があったが、プレスをしても原料の大きさ
のバラツキが存在し、更に組成の不均一という問題が存
在していた。また、原料をプレスし、更にそれを溶接す
るという工程は、どうしても手間がかかり、工程が複雑
になることは避けられなかった。しかも、この様にして
製造された電極内には、原料から混入する介在物が存在
したり、電極自体が溶解中に溶接継ぎ手が外れるなどの
問題があり、これらを解決することが非常に困難であっ
た。更に、嵩密度が小さいために、どうしても電極が大
型化する傾向があった。For example, vacuum arc furnace remelting method (VAR method)
In the method for producing titanium or a titanium alloy by using such a method, there is a demand for an electrode for a VAR method having a uniform composition without inclusions. However, in the conventional method, since the raw materials are of various sizes, when manufacturing the electrodes, it was necessary to make the sizes of the raw materials uniform and to perform pressing in order to make them easier to weld. However, there is a problem that the raw materials vary in size and the composition is not uniform. In addition, the process of pressing the raw material and further welding the same is inevitably troublesome and inevitably complicates the process. In addition, the electrodes manufactured in this way have problems such as the presence of inclusions mixed in from the raw materials and the welding joint coming off during melting of the electrodes themselves, which is very difficult to solve. Met. Furthermore, since the bulk density is small, the electrode tends to be necessarily increased in size.
【０００４】また、上記の様に従来法でプレス・溶接し
て製造された電極を用いて、VAR法にて合金を製造した
場合、均一な組成を有する合金を製造するためには、VA
R法を2〜3回繰返して製造しなければならないという問
題もある。Further, when an alloy is manufactured by the VAR method using an electrode manufactured by pressing and welding by a conventional method as described above, in order to manufacture an alloy having a uniform composition, VA is required.
There is also a problem that the R method has to be repeated two or three times to produce.
【０００５】Tiスクラップを一括して溶融する方法とし
ては、大型のコールドクルーシブル誘導溶解装置を用い
る方法が期待されてはいるが、実際にはその溶解方法に
ついて十分に検討されておらず、効率的にTiスクラップ
を溶解するには、次の様な、技術的に未解決の問題が残
されていた。第1に、Tiスクラップには、ゴルフ用部品
や時計用部品等の打ち抜き屑，圧延片端材（スラブのへ
た等），切削屑等、種々の大きさや形状のものがあり、
これらのTiスクラップをむやみに炉内に装入しても溶け
残りや出湯不良が起こり、所定の出湯量を得ることは非
常に困難である。第2に、Tiスクラップ中には切削工程
に起因する切削工具の破損片等が混入していることが多
く、これらの異物をTiスクラップから完全に分離除去す
ることは困難であり、更に従来の溶解方法では上記異物
を完全に溶解させることができなかった。溶け残った上
記異物は高密度介在物（HDI）や低密度介在物（LDI）等
とも呼ばれ、Tiスクラップの利用が増やせない原因とも
なっていた。As a method for melting Ti scrap at once, a method using a large-sized cold-crucible induction melting apparatus is expected, but the melting method has not been sufficiently studied in practice, so that an efficient method has been proposed. In dissolving Ti scrap into steel, the following technically unsolved problems remain. Firstly, there are various types and shapes of Ti scrap, such as punching scraps for golf parts and watch parts, rolled scraps (slabs and the like), cutting scraps, and the like.
Even if these Ti scraps are unnecessarily charged into the furnace, undissolved or poor tapping occurs, and it is very difficult to obtain a predetermined tapping amount. Second, broken pieces of the cutting tool due to the cutting process are often mixed in Ti scrap, and it is difficult to completely separate and remove these foreign matters from Ti scrap. The dissolving method could not completely dissolve the foreign matter. The undissolved foreign substances are also referred to as high-density inclusions (HDI) and low-density inclusions (LDI), and have been factors that cannot increase the use of Ti scrap.
【０００６】[0006]
【発明が解決しようとする課題】本発明は上記事情に着
目してなされたものであって、大量のTiスクラップを一
括して効率的に溶解する方法の提供を第1の課題とする
ものであり、また上記介在物の問題のないTiスクラップ
の溶解方法の提供を第2の課題とするものである。第3の
課題として均一な組成を有する真空アーク炉再溶解法用
に適した電極を提供するものである。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a method for efficiently dissolving a large amount of Ti scrap in a lump. It is another object of the present invention to provide a method for dissolving Ti scrap which does not have the problem of inclusions. A third object is to provide an electrode having a uniform composition and suitable for a vacuum arc furnace remelting method.
【０００７】[0007]
【課題を解決するための手段】上記第1の課題を解決し
た本発明とは、るつぼ底面に配設された出湯ノズルの上
部がテーパ状に形成されたコールドクルーシブル誘導溶
解装置を用いて、種々の大きさを有するチタン又はチタ
ン合金製スクラップを溶解する方法であって、溶解開始
前及び溶解開始後に、球相当径がノズル内径の2倍以下
である小型スクラップが、上記出湯ノズル上部のテーパ
部空間に入らない様にスクラップを装入して誘導溶解を
行うことを要旨とするものであり、上記コールドクルー
シブル誘導溶解装置を用いてチタン又はチタン合金製ス
クラップを溶解するにあたっては、るつぼ内のスクラッ
プ嵩密度がチタンの真密度の3割以上となる様にスクラ
ップを装入して誘導溶解を行うことが推奨される。According to the present invention which solves the above first problem, a cold crucible induction melting apparatus in which an upper part of a tapping nozzle arranged on the bottom of a crucible is formed in a tapered shape is used. A method of melting a titanium or titanium alloy scrap having a size of, before and after the start of melting, a small scrap having an equivalent sphere diameter of twice or less the inner diameter of the nozzle, the tapered portion at the top of the tapping nozzle The purpose is to perform induction melting by loading a scrap so as not to enter a space.When melting the titanium or titanium alloy scrap using the cold crucible induction melting apparatus, the scrap in the crucible is used. It is recommended that scrap be charged and induction melting be performed so that the bulk density is 30% or more of the true density of titanium.
【０００８】また上記第2の課題を解決した本発明と
は、切削工程に起因する高融点材料を異物として含むチ
タン又はチタン合金製スクラップをコールドクルーシブ
ル誘導溶解装置を用いて溶解する方法であって、上記チ
タン又はチタン合金製スクラップを溶解させた後、10分
間以上溶湯のままるつぼ内に保持することで上記異物を
溶解させることを要旨とするものである。The present invention which solves the second problem is a method of melting titanium or titanium alloy scrap containing a high melting point material as a foreign substance resulting from a cutting process using a cold crucible induction melting apparatus. The gist of the present invention is to dissolve the foreign matter by dissolving the titanium or titanium alloy scrap and holding the molten metal in a crucible for 10 minutes or more.
【０００９】更に、チタン又はチタン合金製スクラップ
とスポンジチタンをコールドクルーシブル誘導溶解装置
を用いて溶解するにあたっては、上記スクラップを溶解
させて下湯をるつぼ内に溶製した後、スポンジチタンを
るつぼ内に添加し誘導溶解を行うことが望ましい。Further, in dissolving titanium or titanium alloy scrap and sponge titanium using a cold crucible induction melting apparatus, the scrap is melted, and sewage is melted in a crucible. To induce dissolution.
【００１０】尚、上記のいずれの方法においても、チタ
ン又はチタン合金製スクラップと共に、チタン又はチタ
ン合金製鋳塊を用いてもよい。[0010] In any of the above methods, a titanium or titanium alloy ingot may be used together with titanium or a titanium alloy scrap.
【００１１】第3の課題を解決するためには、上記のい
ずれかの溶解方法において溶解された溶湯を鋳造して真
空アーク炉再溶解法用の電極を製造すれば良い。In order to solve the third problem, the molten metal melted by any of the above-mentioned melting methods may be cast to produce an electrode for a vacuum arc furnace remelting method.
【００１２】[0012]
【発明の実施の形態】Tiスクラップ原料は、前述の通
り、種々の大きさや形状であることから、真空アーク溶
解法，電子ビーム溶解法やプラズマ溶解法などといった
従来の方法では溶解対象のTiスクラップを細かく切断す
る必要がある。これに対して、水冷銅るつぼ等を用いた
コールドクルーシブル誘導溶解においては、スクラップ
の切断等の作業が不要であることが大きな利点となる。
しかしながら、るつぼ底面に配設された出湯ノズルの上
部がテーパ状に形成されたコールドクルーシブル誘導溶
解装置を用いて、種々の大きさを有するチタン又はチタ
ン合金製スクラップを溶解して出湯しようとしても、ス
ムーズに溶湯を出湯できなかった。DETAILED DESCRIPTION OF THE INVENTION As described above, Ti scrap raw materials have various sizes and shapes, and therefore, Ti scrap to be melted by a conventional method such as a vacuum arc melting method, an electron beam melting method, or a plasma melting method. Need to be cut finely. On the other hand, in the cold crucible induction melting using a water-cooled copper crucible or the like, it is a great advantage that work such as cutting of scrap is not required.
However, using a cold crucible induction melting device in which the top of a tapping nozzle arranged on the bottom of the crucible is formed in a tapered shape, even if melting titanium or titanium alloy scrap having various sizes is attempted to be melted, and hot water is melted. The melt could not be poured smoothly.
【００１３】本発明者らが出湯不良の原因を調査したと
ころ、次の様な知見を得た。即ち、溶解処理の途中段階
で、出湯ノズルの上部に形成されたテーパ部に、溶湯が
小型（小径）のスクラップを巻き込んで入り込み、水冷
されているテーパ部の銅セグメントにより冷却され一旦
これが凝固してしまうと、出湯時にこの部分を溶解すべ
く誘導加熱を行っても、小型スクラップを巻き込んで固
まった溶湯部分が先に溶解し、小型スクラップに誘導が
かかりにくいことから溶け残り易く、この小型スクラッ
プが完全に溶解しない状態で出湯が始まると、ノズル内
に小型スクラップが入り込み、このスクラップが起点と
なって凝固が進行してノズルの閉塞等の出湯不良を引き
起こしていたことが分かった。そこで本発明者らは出湯
不良を防止するために、スクラップを装入する際に、こ
のような溶解途中に出湯ノズルのテーパ部内へ溶湯が小
型スクラップを巻き込んで流入することを防ぐ様にTiス
クラップを装入することで、このような問題点を解決で
きることを見出し、本発明に想到した。具体的には、図
1に示す様に、出湯ノズル2のテーパ上部（るつぼ1の底
部1aと出湯ノズル2のテーパ面2aの境界部）において大
型スクラップ3でテーパ部空間を覆い、上記空間内には
全くスクラップのない状態にする方法を採用すれば、サ
イズの小さい（好ましくは球相当径に直してノズル内径
の2倍以下の）小型スクラップ4が出湯ノズル2の直上に
入り込むのを防ぐことができる。或いは、図2に示す様
に、ノズル内径よりも大きい（好ましくはノズル内径の
3倍以上の）中型スクラップ5でテーパ部に装入可能なも
のを置き、出湯ノズル2の上部を覆う方法を採用しても
よい。The present inventors have investigated the causes of poor tapping and found the following findings. In other words, in the middle of the melting process, the molten metal is wound around a small-sized (small-diameter) scrap into the tapered portion formed above the tapping nozzle, cooled by the water-cooled copper segment of the tapered portion, and once solidified. Even if induction heating is performed to melt this part at the time of tapping, the molten metal part that has been entangled by the small scrap melts first, and it is difficult for the small scrap to be guided. It was found that when tapping was started in a state in which was not completely dissolved, small scraps entered the nozzles, and the scraps served as a starting point for solidification to progress, causing poor tapping such as nozzle blockage. Therefore, in order to prevent poor tapping of the molten metal, the present inventors have found that when loading the scrap, it is necessary to prevent the molten metal from being trapped and flowing into the tapered portion of the tapping nozzle during such melting so as to prevent the small scrap from flowing into the tapered portion. It has been found that such a problem can be solved by inserting the. Specifically,
As shown in FIG. 1, the tapered upper portion of the tapping nozzle 2 (the boundary between the bottom 1a of the crucible 1 and the tapered surface 2a of the tapping nozzle 2) covers the tapered space with a large scrap 3, and there is no scrap in the space. By adopting the method of setting the state, it is possible to prevent the small scrap 4 having a small size (preferably, converted into a sphere equivalent diameter and not more than twice the inner diameter of the nozzle) from entering just above the tapping nozzle 2. Alternatively, as shown in FIG. 2, it is larger than the inner diameter of the nozzle (preferably,
A method in which a medium-sized scrap 5 (three times or more) that can be inserted into the tapered portion may be placed to cover the top of the tapping nozzle 2 may be adopted.
【００１４】またTiスクラップには嵩高いものも多く、
通常の方法で炉内に装入しても、必ずしも溶解ができな
いことが分かった。本発明者らが種々の検討を行った結
果、図3のグラフに示す通り、最低でもるつぼに装入し
たスクラップの嵩密度がチタンの真密度の3割以上に相
当する量を装入しなければ溶解しないことを突き止め
た。溶解所要時間を短縮するという観点から、チタンの
真密度に対するるつぼ装入原料の嵩密度の割合は、4割
以上が望ましく、5割以上であればより望ましい。Many Ti scraps are bulky,
It was found that melting was not always possible even when charged into the furnace by the usual method. As a result of various studies conducted by the present inventors, as shown in the graph of FIG. 3, the bulk density of the scrap loaded in the crucible must be at least an amount corresponding to 30% or more of the true density of titanium. Found that it would not dissolve. From the viewpoint of shortening the melting time, the ratio of the bulk density of the crucible charge to the true density of titanium is preferably 40% or more, and more preferably 50% or more.
【００１５】更に、Tiスクラップでは、スクラップ中に
含まれる切削工具屑等の異物を除去することは非常に困
難であり、Tiスクラップを溶解して鋳造した場合、上記
異物に起因する欠陥の発生が問題となっている。Tiスク
ラップとして代表的な切削工具屑である炭化タングステ
ン（WC）を例にとると、溶湯中では以下の反応により溶
解が進行するが、この溶解速度は非常に遅く、通常の真
空アーク溶解法や電子ビーム溶解法等の従来法では溶解
しきることができなかった。Further, in the case of Ti scrap, it is very difficult to remove foreign matter such as cutting tool chips contained in the scrap. When Ti scrap is melted and cast, defects caused by the foreign matter may occur. It is a problem. Taking tungsten carbide (WC), which is a typical cutting tool waste as a scrap of Ti, as an example, the melting proceeds in the molten metal by the following reaction, but the melting speed is very slow. Conventional methods such as the electron beam melting method have not been able to completely dissolve.
【００１６】ＷＣ→Ｗ＋Ｃ これに対して、コールドクルーシブル誘導溶解装置を用
いる本発明方法では、切削工具屑等の融点が、溶解チタ
ン及びチタン合金の融点より高い温度（融点＋100℃以
内）であっても、溶湯の撹拌力が非常に強いため、十分
に溶解することが可能であることを本発明者らは見出し
た。WCの様に、異物の融点が溶解するチタン及びチタン
合金の融点＋100℃以内であれば、図4に示す通り、溶湯
中に10分間以上保持することで、切削工程に起因して混
入すると考えられる最大の異物（切削工具屑等）であっ
ても、溶湯中にほぼ完全に溶解することが可能であり、
より確実に溶解するには15分以上保持することが望まし
い。WC → W + C On the other hand, in the method of the present invention using the cold crucible induction melting apparatus, the melting point of cutting tool chips and the like is higher than the melting points of the molten titanium and titanium alloy (with a melting point of + 100 ° C. or less). Also, the present inventors have found that the melting power of the molten metal is so strong that it can be sufficiently dissolved. As shown in Fig. 4, if the melting point of the foreign material is within + 100 ° C of the melting point of titanium and titanium alloys, as in WC, it is considered that it will be mixed in due to the cutting process by holding it in the molten metal for 10 minutes or more as shown in Fig. 4. Even the largest foreign matter (such as cutting tool chips) that can be dissolved almost completely in the molten metal,
For more reliable dissolution, it is desirable to hold for 15 minutes or more.
【００１７】尚、Tiスクラップ以外に、原料としてスポ
ンジチタンを併用する場合には、溶解効率が著しく低下
する。その原因は、スポンジチタンとTiスクラップを同
時にルツボ内に装入するとスポンジチタン内に含まれて
いるMgCl2が溶解初期に発生してるつぼ壁に付着し、更
には凝固スカルに付着して抜熱量が多くなり冷却が強化
されることに起因して、溶解効率及び出湯効率が非常に
悪くなっているものである。本発明者らが、これを防ぐ
ため様々な検討を行った結果、スポンジチタンを併用す
るときは、先にスクラップ及び／又は鋳塊を溶解し、る
つぼ内に下湯を溶製してからスポンジチタンを添加する
ことで、MgCl2がるつぼ壁に付着することを防ぐことが
可能となり、溶解効率及び出湯効率良く溶解・鋳造する
ことが可能になることを見出した。また、下湯は一旦炉
内で凝固させ、スポンジチタンをその上に装入してから
再度加熱して溶解・鋳造することも同様の理由からMgCl
2を防ぐことができるので好ましい。When titanium sponge is used as a raw material in addition to Ti scrap, the dissolution efficiency is significantly reduced. The cause is that when titanium sponge and Ti scrap are loaded into a crucible at the same time, MgCl 2 contained in the titanium sponge is generated in the early stage of melting and adheres to the crucible wall, and further adheres to the solidified skull and heat dissipation And the cooling efficiency is increased, so that the melting efficiency and tapping efficiency are very poor. As a result of various studies conducted by the present inventors to prevent this, when titanium sponge is used in combination, the scrap and / or ingot are first dissolved, and the sponge is melted in the crucible. It has been found that by adding titanium, it is possible to prevent MgCl 2 from adhering to the crucible wall, and it is possible to perform melting and casting with high melting efficiency and tapping efficiency. It is also possible to solidify the sewage in a furnace once, put titanium sponge on it, heat it again, and melt and cast it.
2 is preferred because it can be prevented.
【００１８】更に、コールドクルーシブル誘導溶解装置
を用いる本発明方法では、大量のTiスクラップを一括し
て効率的に溶解ができ、介在物の問題のない溶湯を得る
ことができる。よって、該方法を用いて溶解された溶湯
を鋳造して製造されたVAR法用電極は、従来の溶接継ぎ
足し物ではない一体物とすることができ、その電極を一
度で介在物のない均一な組成とすることができる。溶湯
を鋳造する方法には重力鋳造や差圧鋳造、底注ぎ鋳造、
横注ぎ鋳造等が適用でき、鋳造条件は溶解金属の融点以
上、具体的には融点＋100℃程度の溶湯を鋳型に流し込
み、上述の鋳造方法を用いることにより、VAR法に適し
た電極を得ることができる。また、本発明の溶解方法で
電極を製造すると、溶湯を保持している間に合金成分を
調整できるので、どのような合金化も容易となり、また
希望重量の電極を一回の溶解で製造することが可能とな
り、原料が含んでいる可能性のある介在物を完全に溶解
し、成分が均一で電極中に介在物が全く存在しない電極
とすることができる。そして、該電極を使用してVAR法
による溶解、鋳造を行うことによって、一度で介在物な
ど欠陥のない高品質なチタンやチタン合金製品を製造す
ることができ、従来の様に均一な組成の合金を得るため
にVAR法を何度も繰り返す必要は無く、効率良く合金を
製造することができる。Further, in the method of the present invention using the cold-crucible induction melting apparatus, a large amount of Ti scrap can be efficiently melted in a lump and a molten metal free from inclusions can be obtained. Therefore, the electrode for the VAR method manufactured by casting a molten metal that is melted by using the method can be an integrated body that is not a conventional welded joint, and the electrode can be uniformly formed without inclusions at one time. It can be a composition. Methods of casting molten metal include gravity casting, differential pressure casting, bottom casting,
Applicable to horizontal casting, etc., the casting conditions are higher than the melting point of the molten metal, specifically, a molten metal with a melting point of about + 100 ° C is poured into a mold, and an electrode suitable for the VAR method is obtained by using the casting method described above. Can be. Further, when the electrode is manufactured by the melting method of the present invention, the alloying components can be adjusted while holding the molten metal, so that any alloying becomes easy, and the electrode having a desired weight is manufactured by one melting. This makes it possible to completely dissolve inclusions that may be contained in the raw material, and to provide an electrode having uniform components and no inclusions in the electrodes. Then, by performing melting and casting by the VAR method using the electrode, a high-quality titanium or titanium alloy product without defects such as inclusions can be manufactured at once, and a uniform composition as in the related art can be produced. It is not necessary to repeat the VAR method many times to obtain the alloy, and the alloy can be manufactured efficiently.
【００１９】以下、本発明を実施例によって更に詳細に
説明するが、下記実施例は本発明を限定する性質のもの
ではなく、前・後記の主旨に徴して設計変更することは
いずれも本発明の技術的範囲内に含まれるものである。Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are not intended to limit the present invention. Are included within the technical scope of
【００２０】[0020]
【実施例】実施例1 るつぼ内径400mmのコールドクルーシブル誘導溶解装置
を用いて、チタン200kg相当の炉体容積に対し、Tiの切
削屑120kgと板状のスクラップを50kgを無作為に装入し
て15分間保持して溶解を行い、出湯を行った。その結
果、約50kgの溶湯が出湯した時点でノズルが閉塞し、残
りの溶湯は出湯できなかった。 EXAMPLE 1 Using a cold crucible induction melting apparatus with a crucible inner diameter of 400 mm, 120 kg of titanium cuttings and 50 kg of plate-like scrap were randomly charged into a furnace body volume equivalent to 200 kg of titanium. Dissolution was carried out by holding for 15 minutes, and tapping was performed. As a result, when about 50 kg of molten metal was discharged, the nozzle was closed, and the remaining molten metal could not be discharged.
【００２１】次にノズル直上とテーパ部に小さなスクラ
ップが入らない様に、先に大きな板スクラップで上記テ
ーパ部を覆い、その後Tiの切削屑を装入して溶解を行
い、出湯を行った。その結果、170kgの全ての溶湯が出
湯できた（本発明例1）。Next, the tapered portion was first covered with a large plate scrap so as to prevent small scraps from entering just above the nozzle and into the tapered portion. Thereafter, Ti chips were charged and melted, and tapping was performed. As a result, all of the 170 kg of molten metal was discharged (Example 1 of the present invention).
【００２２】実施例2 前記コールドクルーシブル誘導溶解装置を用いて、本発
明例1と同様にして、チタン200kg相当の炉体容積に対
し、板状のスクラップ50kgを装入して15分間誘導溶解を
試みたが溶解しなかった。 Example 2 In the same manner as in Example 1 of the present invention, 50 kg of a plate-shaped scrap was charged into a furnace body equivalent to 200 kg of titanium, and induction melting was performed for 15 minutes using the cold crucible induction melting apparatus. Tried but did not dissolve.
【００２３】次に、板スクラップ50kgに加えてTiの切削
屑120kgを装入して誘導溶解を行ったところ溶解し、溶
湯を5分間保持して出湯し鋳造を行った。但し、圧延後
にJISZ3107に準拠してX線検査を行ったところ、介在物
が確認された。Next, in addition to 50 kg of the plate scrap, 120 kg of cutting chips of Ti were charged and induction melting was performed. The melt was melted, the molten metal was held for 5 minutes, and the molten metal was discharged and cast. However, when an X-ray inspection was performed after rolling in accordance with JISZ3107, inclusions were confirmed.
【００２４】更に、板スクラップ50kgに加えてTiの切削
屑120kgを装入して誘導溶解を行ったところ溶解し、溶
湯を15分間保持して出湯し鋳造を行った。圧延後にJIS
Z3107に準拠してX線検査を行ったところ、介在物は全
く確認されなかった（本発明例2）。Further, in addition to 50 kg of plate scrap, 120 kg of Ti cuttings were charged and induction melting was performed. The melt was melted, and the molten metal was held for 15 minutes to be cast and cast. JIS after rolling
When X-ray inspection was performed in accordance with Z3107, no inclusions were confirmed (Example 2 of the present invention).
【００２５】実施例3 溶解原料として、スラブへたのスクラップを50kg、Tiの
切削屑を50kg、スポンジチタンを80kgを用いたこと以外
は、実施例2と同様にして溶湯保持時間を5分間と15分間
の2通り行い、出湯量を調べると共に、圧延後にX線検査
を行った。次に、スラブへたのスクラップを50kgとTiの
切削屑を50kgを5分間または15分間の溶湯保持を行って
出湯量を調べると共に、圧延後にX線検査を行った。X線
検査はJIS規格Z3107に準拠して行い、検出限界0.4mmφ
の介在物と欠陥がある場合を×、介在物は無いが欠陥が
存在する場合を△、介在物も欠陥もない場合を○として
評価した。結果を表1に示す。 Example 3 The molten metal holding time was set to 5 minutes in the same manner as in Example 2 except that 50 kg of scrap to a slab, 50 kg of cutting chips of Ti, and 80 kg of titanium sponge were used as melting raw materials. The test was carried out twice for 15 minutes to check the amount of molten metal and to perform X-ray inspection after rolling. Next, 50 kg of scrap to the slab and 50 kg of cutting chips of Ti were held for 5 minutes or 15 minutes to determine the amount of molten metal, and X-ray inspection was performed after rolling. X-ray inspection is performed in accordance with JIS standard Z3107, detection limit 0.4 mmφ
Was evaluated as × when there was an inclusion and a defect, Δ when there was no inclusion but a defect, and ○ when there was no inclusion and no defect. Table 1 shows the results.
【００２６】[0026]
【表1】 【table 1】
【００２７】スポンジチタンをスクラップと共に溶解さ
せる際には、スクラップと同時に装入するのではなく、
スクラップを溶解後にスポンジチタンを追加投入して溶
解する方が溶解し易いことが分かる。When dissolving the titanium sponge together with the scrap, instead of charging the titanium at the same time as the scrap,
It turns out that it is easier to dissolve by additionally adding and dissolving titanium sponge after dissolving the scrap.
【００２８】実施例4 本発明例として、るつぼ内径600mmのコールドクルーシ
ブル誘導溶解装置を用いて、Ti-6Al-4V合金の塊状スク
ラップ150kgをるつぼ底に挿入・溶解し、更にスポンジ
チタン、Al-V母合金及び粒状AlをTi-6Al-4V合金組成と
なるように配合して、合計原料挿入量が550kgとなるよ
うにした。原料が完全に溶解してから30分間溶湯を保持
し、その後溶湯出湯を行って鋳造し、VAR用電極を製造
した。また、該電極を用いてVAR法による溶解鋳造を行
い、VAR一次鋳塊を得た。 Example 4 As an example of the present invention, using a cold crucible induction melting apparatus with a crucible inner diameter of 600 mm, 150 kg of massive scrap of Ti-6Al-4V alloy was inserted and melted in the crucible bottom, and then sponge titanium, Al-V The master alloy and the granular Al were blended to have a Ti-6Al-4V alloy composition so that the total raw material insertion amount was 550 kg. The molten metal was held for 30 minutes after the raw material was completely melted, and then the molten metal was poured and cast to produce a VAR electrode. In addition, melting casting was performed by the VAR method using the electrodes to obtain a VAR primary ingot.
【００２９】また、比較例として、スポンジチタン、Al
-V母合金、粒状AlをTi-6Al-4V合金組成となるように配
合し、プレス成形後溶接してVAR用電極を製造した。該
電極を用いてVAR法による溶解鋳造を行い、VAR一次鋳塊
を得た。更に、該VAR一次鋳塊をVAR用電極として再びVA
R法による溶解鋳造を行い、VAR二次鋳塊を得た。As comparative examples, sponge titanium, Al
-V master alloy and granular Al were mixed so as to have a Ti-6Al-4V alloy composition, pressed, welded, and VAR electrodes were manufactured. Using the electrode, melting casting was performed by the VAR method to obtain a VAR primary ingot. Further, the VAR primary ingot is used again as a VAR electrode and the VA
Melting casting by the R method was performed to obtain a VAR secondary ingot.
【００３０】上記の様に得られたVAR用電極、VAR一次鋳
塊、VAR二次鋳塊の中央部からサンプルを採取し、湿式
分析（金属元素はICP発光分光分析、ガスは不活性ガス
融解法）を行った。結果を下記表2に示す。Samples were collected from the center of the VAR electrode, VAR primary ingot, and VAR secondary ingot obtained as described above, and were subjected to wet analysis (metal element for ICP emission spectroscopy, gas for inert gas fusion). Method). The results are shown in Table 2 below.
【００３１】[0031]
【表2】 [Table 2]
【００３２】上記表2から考察すると、コールドクルー
シブル誘導溶解装置を用いる本発明の溶解方法では、ほ
ぼ均一な成分組成を有するVAR用電極を製造することが
できた。また、該電極の組成はTi-6Al-4V合金製品とし
ても十分別使用できるものであり、再度のVARを施すま
でもない様な良好な成分組成（±0.1質量%の精度）を有
する電極であった。As can be seen from Table 2, the dissolution method of the present invention using the cold crucible induction melting apparatus was able to produce a VAR electrode having a substantially uniform component composition. In addition, the composition of the electrode can be used separately as a Ti-6Al-4V alloy product, and is an electrode having a good component composition (accuracy of ± 0.1 mass%) such that it is not necessary to perform VAR again. there were.
【００３３】一方、従来のようにプレス後溶接して製造
されたVAR用電極は、成分組成がかなり不均一であり、
該電極を用いてVARを一度施して得られるVAR一次鋳塊で
もまだバラツキがある。この様な中間段階のものから成
分組成が均一な製品を得る為には、該一次鋳塊を電極と
し、再びVARを行いVAR二次鋳塊を得なければならない。
この様に、従来の方法で得られるVAR法用電極を用いる
と、最終製品を得るまでに多くの工程が必要となる。On the other hand, the conventional VAR electrode manufactured by pressing and welding after welding has a considerably non-uniform component composition.
The VAR primary ingot obtained by applying VAR once using the electrode still has variations. In order to obtain a product having a uniform component composition from such an intermediate stage, the primary ingot is used as an electrode, and VAR must be performed again to obtain a VAR secondary ingot.
As described above, when the VAR electrode obtained by the conventional method is used, many steps are required until a final product is obtained.
【００３４】[0034]
【発明の効果】本発明は以上の様に構成されているの
で、大量のTiスクラップを一括して効率的に溶解する方
法が提供できることとなり、また上記介在物の問題のな
いスクラップの溶解方法が提供できることとなった。更
に、本発明の溶解方法により溶解された溶湯を鋳造する
と真空アーク炉再溶解法に適した電極を提供できるよう
になった。Since the present invention is configured as described above, it is possible to provide a method for efficiently dissolving a large amount of Ti scrap at once, and a method for dissolving scrap without the above-mentioned problem of inclusions is provided. It can be provided. Further, when the molten metal melted by the melting method of the present invention is cast, an electrode suitable for a vacuum arc furnace remelting method can be provided.
【図１】本発明に係るTiスクラップの装入方法の一例を
示す説明図である。FIG. 1 is an explanatory view showing an example of a method for charging Ti scrap according to the present invention.
【図２】本発明に係るTiスクラップの装入方法の他の例
を示す説明図である。FIG. 2 is an explanatory view showing another example of the method for charging Ti scrap according to the present invention.
【図３】装入条件と溶解所要時間の関係を示すグラフで
ある。FIG. 3 is a graph showing the relationship between charging conditions and required melting time.
【図４】切削工具屑（WC）の溶湯中における保持時間
と、溶湯中の元素濃度の関係を示すグラフである。FIG. 4 is a graph showing a relationship between a retention time of cutting tool waste (WC) in a molten metal and an element concentration in the molten metal.
1 るつぼ 2 出湯ノズル 3 大型スクラップ 4 小型スクラップ 5 中型スクラップ 1 Crucible 2 Hot tap nozzle 3 Large scrap 4 Small scrap 5 Medium scrap
フロントページの続き (72)発明者 草道 龍彦 神戸市西区高塚台１丁目５番５号 株式会 社神戸製鋼所神戸総合技術研究所内 Ｆターム(参考） 3K059 AB16 AB27 AD01 AD05 4K001 AA27 BA22 BA23 FA14 GA17 GB02 4K046 AA01 BA03 CA01 CD02 CE01 EA01 Continued on the front page (72) Inventor Tatsuhiko Kusamichi 1-5-5 Takatsukadai, Nishi-ku, Kobe F-term in Kobe Steel Research Institute Kobe Research Institute (reference) 3K059 AB16 AB27 AD01 AD05 4K001 AA27 BA22 BA23 FA14 GA17 GB02 4K046 AA01 BA03 CA01 CD02 CE01 EA01
Claims (6)
部がテーパ状に形成されたコールドクルーシブル誘導溶
解装置を用いて、種々の大きさを有するチタン又はチタ
ン合金製スクラップを溶解する方法であって、 溶解開始前及び溶解開始後に、球相当径がノズル内径の
2倍以下である小型スクラップが、上記出湯ノズル上部
のテーパ部空間に入らない様にスクラップを装入して誘
導溶解を行うことを特徴とするチタン又はチタン合金製
スクラップの溶解方法。1. A method for melting titanium or titanium alloy scrap having various sizes using a cold crucible induction melting device in which an upper part of a tapping nozzle arranged on a bottom of a crucible is formed in a tapered shape. Before and after the start of melting, the equivalent ball diameter is
A method for melting a titanium or titanium alloy scrap, wherein a scrap is charged so as to prevent a small scrap of twice or less from entering the tapered space above the tapping nozzle.
いてチタン又はチタン合金製スクラップを溶解する方法
であって、 るつぼ内のスクラップ嵩密度がチタンの真密度の3割以
上となる様にスクラップを装入して誘導溶解を行うこと
を特徴とするチタン又はチタン合金製スクラップの溶解
方法。2. A method for melting a titanium or titanium alloy scrap using a cold crucible induction melting apparatus, wherein the scrap is loaded so that the bulk density of the scrap in the crucible is 30% or more of the true density of titanium. And melting the titanium or titanium alloy scrap by induction melting.
して含むチタン又はチタン合金製スクラップをコールド
クルーシブル誘導溶解装置を用いて溶解する方法であっ
て、 上記チタン又はチタン合金製スクラップを溶解させた
後、10分間以上溶湯のままるつぼ内に保持することで上
記異物を溶解させることを特徴とするチタン又はチタン
合金製スクラップの溶解方法。3. A method for melting a titanium or titanium alloy scrap containing a high melting point material as a foreign substance due to a cutting process using a cold crucible induction melting device, wherein the titanium or titanium alloy scrap is melted. A method for melting scrap made of titanium or a titanium alloy, wherein the foreign matter is melted by holding the melt in a crucible for at least 10 minutes.
ポンジチタンをコールドクルーシブル誘導溶解装置を用
いて溶解する方法であって、 上記スクラップを溶解させて下湯をるつぼ内に溶製した
後、スポンジチタンをるつぼ内に添加し誘導溶解を行う
ことを特徴とするチタン又はチタン合金製スクラップの
溶解方法。4. A method of melting titanium or titanium alloy scrap and sponge titanium using a cold crucible induction melting device, wherein the scrap is melted, and sewage is melted in a crucible. A method for dissolving scrap made of titanium or a titanium alloy, wherein the scrap is added to a crucible for induction melting.
に、チタン又はチタン合金製鋳塊を用いる請求項1〜4の
いずれかに記載の溶解方法。5. The melting method according to claim 1, wherein a titanium or titanium alloy ingot is used together with the titanium or titanium alloy scrap.
溶製された溶湯を鋳造して製造されてなることを特徴と
する真空アーク炉再溶解法用の電極。6. An electrode for a vacuum arc furnace remelting method, which is produced by casting a molten metal produced by the method according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000255491A JP4652537B2 (en) | 1999-10-28 | 2000-08-25 | Method for melting titanium or titanium alloy scrap |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11-307487 | 1999-10-28 | ||
| JP30748799 | 1999-10-28 | ||
| JP2000255491A JP4652537B2 (en) | 1999-10-28 | 2000-08-25 | Method for melting titanium or titanium alloy scrap |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001192743A true JP2001192743A (en) | 2001-07-17 |
| JP4652537B2 JP4652537B2 (en) | 2011-03-16 |
Family
ID=26565127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000255491A Expired - Lifetime JP4652537B2 (en) | 1999-10-28 | 2000-08-25 | Method for melting titanium or titanium alloy scrap |
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| Country | Link |
|---|---|
| JP (1) | JP4652537B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113124681A (en) * | 2021-03-22 | 2021-07-16 | 洛阳双瑞精铸钛业有限公司 | Material box for titanium and titanium alloy EB smelting |
| CN113881854A (en) * | 2021-10-28 | 2022-01-04 | 西部钛业有限责任公司 | Method for eliminating low-density inclusion defect source of titanium alloy ingot |
| KR20220153795A (en) * | 2021-05-12 | 2022-11-21 | (주)동아특수금속 | Recycling technology of alloy powder scrap for 3D printer |
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| CN113124681A (en) * | 2021-03-22 | 2021-07-16 | 洛阳双瑞精铸钛业有限公司 | Material box for titanium and titanium alloy EB smelting |
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| KR102554527B1 (en) * | 2021-05-12 | 2023-07-12 | (주)동아특수금속 | Recycling technology of alloy powder scrap for 3D printer |
| CN113881854A (en) * | 2021-10-28 | 2022-01-04 | 西部钛业有限责任公司 | Method for eliminating low-density inclusion defect source of titanium alloy ingot |
| CN113881854B (en) * | 2021-10-28 | 2023-08-15 | 西部钛业有限责任公司 | Method for eliminating sources of low-density inclusion defects of titanium alloy cast ingot |
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