EP0249050B1 - Process for the electroslag refining of metals, especially of such metals containing components with a high oxygen affinity - Google Patents
Process for the electroslag refining of metals, especially of such metals containing components with a high oxygen affinity Download PDFInfo
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- EP0249050B1 EP0249050B1 EP87107038A EP87107038A EP0249050B1 EP 0249050 B1 EP0249050 B1 EP 0249050B1 EP 87107038 A EP87107038 A EP 87107038A EP 87107038 A EP87107038 A EP 87107038A EP 0249050 B1 EP0249050 B1 EP 0249050B1
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- slag
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/16—Remelting metals
- C22B9/18—Electroslag remelting
Definitions
- the invention relates to a process for the electroslag remelting of metals which are remelted in the form of at least one current-carrying melting electrode through a molten slag bath under subatmospheric pressure to form a block, the slag being heated by means of alternating current.
- the metallic starting material is remelted through a liquid or molten slag layer to an ingot or block, on the top of which a liquid zone, the so-called melting lake, is maintained.
- the block can be held stationary (in a so-called stand mold) or withdrawn continuously (from a so-called strand mold).
- the starting material is added in the form of a melting electrode.
- the melting and process heat is generated by the electrical resistance of the liquid slag, and the current can be supplied both by the melting electrode and by an additional permanent electrode.
- the block and / or the mold is the electrical opposite pole.
- the electroslag remelting process is known alternatively by means of direct voltage or alternating voltage.
- the electroslag remelting process can also be carried out under subatmospheric pressure, i.e. perform under a pressure below 1 bar, and use permanent electrodes for the supply of the melt stream.
- the metal forming the block can be added in the form of rods, granules or a melt that was produced elsewhere. No information is given on the composition of the starting material. With regard to suitable slag compositions, reference is made to the general literature.
- Another source of white spots which, according to the inventor's own experience, can consist of particles that can originate from the cast electrode if it is made of a superalloy that very often tears open along the stem crystals. It is therefore difficult, if not impossible, to rule out these errors in a VAR block.
- the remelting is carried out under an overheated slag bath, the temperature of which is usually more than 300 ° C. above the liquidus temperature of the superalloy.
- the dendrite skeletons or the particles broken out of the electrode necessarily fall through the overheated slag and consequently have enough time to melt before they reach the melting lake.
- the invention is therefore based on the object of specifying a method for producing blocks from a nickel-containing superalloy which, in addition to nickel, contains at least one oxygen-affine alloy component from the group of the elements aluminum, boron, titanium and zirconium, in which oxidation is prevented, one Degassing takes place and there are no dots, ring patterns or white spots. It is very important that the task in question is solved simultaneously with regard to all subtasks.
- the at least one consumable electrode consists of a nickel-containing superalloy which, in addition to nickel, contains at least one oxygen-affine alloy component from the group of the elements aluminum, boron, titanium and zirconium, and that as Slag an oxide slag of at least 80 percent by weight is used from oxides whose boiling points are above 2000 ° C.
- a pressure of at most 900 mbar can be used.
- vacuum it is particularly useful to work in a pressure range between 200 and 10 ⁇ 2 mbar. In all cases there is sufficient degassing of the melt and any oxidation of the electrode metal and the alloy components is effectively eliminated without sacrificing the advantages of the ESR method in terms of a good block surface, metallurgical work and the avoidance of white spots .
- the slag composition is also of particular importance. So it is e.g. known from the literature that gaseous fluorine compounds continuously emerge from slag mixtures with high fluorine fractions due to the chemical reactions of the fluorine compound with oxidic slag fractions. If such a slag with high fluoride contents were used under vacuum, the reaction would be shifted towards the formation of further volatile fluorides due to the lowering of the partial pressure, so that the process would be difficult to control.
- a slag which consists of at least 80 percent by weight of oxidic components whose boiling points are above 2000 ° C.
- the slag composition remains stable.
- Pure oxide systems such as, for example, come into question CaO, Al2O3 and MgO. It can be particularly advantageous to have CaO and Al2O3 at 48% each and MgO at 4% by weight.
- the height of the slag bath above the block was 70 mm.
- the slag consisted of 48 percent by weight of CaO and Al2O3 and 4 percent by weight of MgO.
- the electrode was operated with a voltage of 35 V and a current of 2300 A. operated. After a remelting period of 15 minutes under a vacuum of 5 x 10 ⁇ 1 mbar, the electrode was melted down to the remainder.
- the block removed from the mold after cooling had a clean, smooth surface and had no "crown".
- Cross-sectional images showed that the block was free of dots of white spots and ring patterns over its entire length and its entire diameter.
- the alloy composition corresponded largely to that of the electrode, ie no erosion of aluminum and titanium was observed.
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Abstract
Description
Die Erfindung betrifft ein Verfahren zum Elektroschlackeumschmelzen von Metallen, die in Form mindestens einer stromführenden Abschmelzelektrode durch ein geschmolzenes Schlackenbad hindurch unter unteratmosphärischem Druck zu einem Block umgeschmolzen werden, wobei die Schlacke mittels Wechselstrom beheizt wird.The invention relates to a process for the electroslag remelting of metals which are remelted in the form of at least one current-carrying melting electrode through a molten slag bath under subatmospheric pressure to form a block, the slag being heated by means of alternating current.
Beim Elektroschlackeumschmelzen wird das metallische Ausgangsmaterial durch eine flüssige bzw. geschmolzene Schlackeschicht hindurch zu einem Ingot oder Block umgeschmolzen, an dessen Oberseite eine flüssige Zone, der sogenannte Schmelzsee, aufrechterhalten wird. Der Block kann dabei stationär (in einer sogenannten Standkokille) festgehalten werden oder kontinuierlich (aus einer sogenannten Strangkokille) abgezogen werden. Das Ausgangsmaterial wird dabei in Form einer Abschmelzelektrode zugesetzt. Die Schmelz- und Prozeßwärme wird durch den elektrischen Widerstand der flüssigen Schlacke erzeugt, wobei die Stromzufuhr sowohl durch die Abschmelzelektrode als auch durch eine zusätzliche Permanentelektrode erfolgen kann. In der Regel ist der Block und/oder die Kokille der elektrische Gegenpol. Es ist bekannt, das Elektroschlackeumschmelzverfahren wahlweise mittels Gleichspannung oder Wechselspannung durchzuführen.In electroslag remelting, the metallic starting material is remelted through a liquid or molten slag layer to an ingot or block, on the top of which a liquid zone, the so-called melting lake, is maintained. The block can be held stationary (in a so-called stand mold) or withdrawn continuously (from a so-called strand mold). The starting material is added in the form of a melting electrode. The melting and process heat is generated by the electrical resistance of the liquid slag, and the current can be supplied both by the melting electrode and by an additional permanent electrode. As a rule, the block and / or the mold is the electrical opposite pole. The electroslag remelting process is known alternatively by means of direct voltage or alternating voltage.
Durch die DE-A-1 483 646 ist es bekannt, das Elektroschlackeumschmelzverfahren auch unter unteratmosphärischem Druck, d.h. unter einem Druck unterhalb 1 bar durchzuführen, und für die Zuführung des Schmelzstroms Permanentelektroden zu verwenden. Das den Block bildende Metall kann dabei in Form von Stangen, Granulat oder einer Schmelze zugesetzt werden, die an anderer Stelle erzeugt wurde. Über die Zusammensetzung des Ausgangsmaterials werden keine Angaben gemacht. Bezüglich geeigneter Schlakkenzusammensetzungen wird auf die allgemeine Literatur verwiesen.From DE-A-1 483 646 it is known that the electroslag remelting process can also be carried out under subatmospheric pressure, i.e. perform under a pressure below 1 bar, and use permanent electrodes for the supply of the melt stream. The metal forming the block can be added in the form of rods, granules or a melt that was produced elsewhere. No information is given on the composition of the starting material. With regard to suitable slag compositions, reference is made to the general literature.
Durch die US-A-4 117 253 ist es ferner bekannt, in einem vakuumdichten Ofengehäuse einen Elektroschlacke-Umschmelzprozeß durchzuführen, bei dem Abschmelzelektroden unter unteratmosphärischem Druck zu Blöcken umgeschmolzen werden. Die Schmelzwärme wird durch Wechselstrom erzeugt; über die Zusammensetzung des Elektrodenmaterials sowie der Schlacke finden sich hingegen keine Angaben.From US-A-4 117 253 it is also known to carry out an electro-slag remelting process in a vacuum-tight furnace housing, in which remelting electrodes are remelted into blocks under subatmospheric pressure. The heat of fusion is generated by alternating current; However, there is no information on the composition of the electrode material and the slag.
In der Zeitschrift "Neue Hütte", Heft 4, April 1979, Seite 157, findet sich eine Kurzbeschreibung eines Forschungsberichtes von Gammal und Hajduk über die Entwicklung von umweltfreundlichen Schlacken für das Elektroschlackeumschmelzverfahren. Es wird eine Schlacke mit einem Masseverhältnis von CaO zu Al₂O₃ von etwa 1,0 und einigen Prozenten MgO angegeben. Die Auswahl erfolgte unter dem Gesichtspunkt der Vermeidung einer Freisetzung von Fluor bzw. Fluor-Verbindungen. Ein Hinweis darauf, daß die spezielle Schlackenzusammensetzung einen vorteilhaften Einfluß auf das Umschmelzen von Nickel-Basis-Legierungen haben könnte, ist nicht zu finden. Darüberhinaus wird das beschriebene Verfahren nicht unter Vakuum durchgeführt, und das Verhalten von Reaktionskomponenten und Schlacke ist unter Vakuum ein anderes als an Atmosphäre.In the magazine "Neue Hütte", issue 4, April 1979, page 157, there is a brief description of a research report by Gammal and Hajduk on the development of environmentally friendly slags for the electro-slag remelting process. There is a slag with a mass ratio of CaO to Al₂O₃ of about 1.0 and a few percent MgO specified. The selection was made from the point of view of avoiding the release of fluorine or fluorine compounds. An indication that the special slag composition could have an advantageous influence on the remelting of nickel-based alloys, cannot be found. Furthermore, the process described is not carried out under vacuum, and the behavior of reaction components and slag under vacuum is different from that in the atmosphere.
Für die Herstellung von Werkstücken mit hohen Anforderungen, insbesondere aus Superlegierungen für rotierende scheibenförmige Teile in Luftfahrt-Triebwerken, wird von den Abnehmern verlangt, daß die Ingots durch das bekannte Vakuum-Umschmelzverfahren (VAR) hergestellt werden, da das Umschmelzen unter Vakuum zu relativ reinen Blöcken führt, die einen sehr geringen Gasgehalt aufweisen. Trotz der Tatsache, daß beim VAR-Verfahren aufgrund einer gerichteten Erstarrung die Blöcke normalerweise frei von Makroseigerungen sind, können einige typische Segregationserscheinungen, wie beispielsweise Pünktchen ("Freckles"), Ringmuster und weiße Flecken ("White Spots") in den Blöcken auftreten. Während Segregationserscheinungen wie die Pünktchen und Ringmuster mehr oder weniger durch sorgfältige Einstellung der Schmelzparameter beherrscht werden können, erscheint die Ausbildung der weißen Flecken unabhängig von den Schmelzbedingungen zu sein. Kürzlich durchgeführte Untersuchungen haben gezeigt, daß die Ausbildung von weißen Flecken nicht die Folge unregelmäßiger Erstarrungsbedingungen an der Erstarrungsfront sind. Es kann angenommen werden, daß die Bestandteile der weißen Flecken folgende sind:
- Skelette aus Dendriten, die während des Abschmelzens von der gegossenen Abschmelzelektrode herabfallen,
- Teilchen, die von der sogenannten "Krone" am oberen Blockrand herunterfallen (die "Krone" ist ein dünner, scharfer Rand oberhalb des Schmelzsees durch Kondensation bzw. Erstarrung von Dämpfen und Spritzern),
- Ablösung von Teilchen von der Erstarrungskante des Schmelzsees.
- Skeletons of dendrites falling from the cast-off electrode during the melting process,
- Particles falling from the so-called "crown" at the top of the block (the "crown" is a thin, sharp edge above the melting lake due to condensation or solidification of vapors and splashes),
- Detachment of particles from the solidification edge of the melting lake.
Eine weitere Quelle der weißen Flecken, die nach eigenen Erfahrungen des Erfinders aus Teilchen bestehen kann, die aus der gegossenen Elektrode stammen können, wenn diese aus einer Superlegierung besteht, die sehr häufig entlang der Stengelkristalle aufreißt. Es ist daher schwer, wenn nicht gar unmöglich, diese Fehler bei einem VAR-Block auszuschliessen.Another source of white spots, which, according to the inventor's own experience, can consist of particles that can originate from the cast electrode if it is made of a superalloy that very often tears open along the stem crystals. It is therefore difficult, if not impossible, to rule out these errors in a VAR block.
Bei dem eingangs beschriebenen ESU-Verfahren wird das Umschmelzen unter einem überhitzten Schlackebad durchgeführt, dessen Temperatur üblicherweise mehr als 300 °C über der Liquidus-Temperatur der Superlegierung liegt. Die Dendriten-Skelette oder die aus der Elektrode herausgebrochenen Teilchen fallen notwendigerweise durch die überhitzte Schlacke und haben infolgedessen ausreichend Zeit zum Aufschmelzen, bevor sie den Schmelzsee erreichen. Auch gibt es beim ESU-Verfahren keine Ausbildung einer Krone am oberen Blockrand. Infolgedessen führt das ESU-Verfahren auch nicht zur Ausbildung von weißen Flecken.In the ESU process described at the outset, the remelting is carried out under an overheated slag bath, the temperature of which is usually more than 300 ° C. above the liquidus temperature of the superalloy. The dendrite skeletons or the particles broken out of the electrode necessarily fall through the overheated slag and consequently have enough time to melt before they reach the melting lake. There is also no formation of a crown at the top of the block in the ESU procedure. As a result, the ESR procedure does not lead to the formation of white spots.
Obwohl die aus dem ESU-Verfahren hervorgegangenen Blöcke mindestens ebenso gut sind wie die aus dem VAR-Verfahren hervorgegangenen Blöcke, fordern die Abnehmer bei Superlegierungen regelmäßig die Anwendung des VAR-Verfahrens für die Herstellung rotierender Scheiben von Luftfahrt-Triebwerken. Der Grund hierfür ist darin zu sehen, daß bei den üblichen ESU-Verfahren nicht nur keine Entgasung des Materials stattfindet, sondern sogar in gewissen Fällen eine zusätzliche Gasaufnahme zu befürchten ist. Hierbei spielen Wasserstoff und Stickstoff die gefährlichste Rolle.Although the blocks resulting from the ESR process are at least as good as the blocks resulting from the VAR process, customers of superalloys regularly request the use of the VAR process for the manufacture of rotating disks for aviation engines. The reason for this is to be seen in the fact that not only does no degassing of the material take place in the usual ESR processes, but that additional gas absorption is even to be feared in certain cases. Hydrogen and nitrogen play the most dangerous role here.
Eine weitere, sehr wesentliche, Gefahr besteht in der Bildung von Oxiden und oxidischen Einschlüssen durch Oxidation des Metalls, insbesondere der sauerstoffaffinen Legierungsbestandteile, durch den umgebenden Luftsauerstoff. Bei diesen sauerstoffaffinen Legierungsbestandteilen handelt es sich um die Elemente Aluminium, Bor, Titan, Zirkonium u.a.. Durch die Oxidation derartiger Legierungsbestandteile entsteht dann ein entsprechender Mangel.Another, very important, danger is the formation of oxides and oxidic inclusions through oxidation of the metal, in particular the alloy components with an affinity for oxygen, by the surrounding atmospheric oxygen. These alloy components with an affinity for oxygen are the elements aluminum, boron, titanium, zirconium, etc. The oxidation of such alloy components results in a corresponding deficiency.
Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren zum Herstellen von Blöcken aus einer nickelhaltigen Superlegierung anzugeben, die zusätzlich zum Nickel mindestens eine sauerstoffaffine Legierungskomponente aus der Gruppe der Elemente Aluminium, Bor, Titan und Zirkonium enthält, bei dem eine Oxidation verhindert wird, eine Entgasung stattfindet und weder Pünktchen, noch Ringmuster, noch weiße Flecken auftreten. Es ist dabei ganz entscheidend, daß die betreffende Aufgabe im Hinblick auf alle Teilaufgaben gleichzeitig gelöst wird.The invention is therefore based on the object of specifying a method for producing blocks from a nickel-containing superalloy which, in addition to nickel, contains at least one oxygen-affine alloy component from the group of the elements aluminum, boron, titanium and zirconium, in which oxidation is prevented, one Degassing takes place and there are no dots, ring patterns or white spots. It is very important that the task in question is solved simultaneously with regard to all subtasks.
Die Lösung der gestellten Aufgabe erfolgt bei dem eingangs beschriebenen Verfahren erfindungsgemäß dadurch, daß die mindestens eine Abschmelzelektrode aus einer nickelhaltigen Superlegierung besteht, die zusätzlich zum Nickel mindestens eine sauerstoffaffine Legierungskomponente aus der Gruppe der Elemente Aluminium, Bor, Titan und Zirkonium enthält, und daß als Schlacke eine zu mindestens 80 Gewichtsprozent oxidische Schlacke aus solchen Oxiden verwendet wird, deren Siedepunkte über 2000 °C liegen.The object is achieved in the method described at the outset according to the invention in that the at least one consumable electrode consists of a nickel-containing superalloy which, in addition to nickel, contains at least one oxygen-affine alloy component from the group of the elements aluminum, boron, titanium and zirconium, and that as Slag an oxide slag of at least 80 percent by weight is used from oxides whose boiling points are above 2000 ° C.
Sofern eine Schutzgasatmosphäre aus Inert- oder Edelgas verwendet wird, kann mit einem Druck von höchstens 900 mbar gearbeitet werden. Bei Verwendung von Vakuum ist es besonders zweckmäßig, in einem Druckbereich zwischen 200 und 10⁻² mbar zu arbeiten. In sämtlichen Fällen findet eine ausreichende Entgasung der Schmelze statt, und jegliche Oxidation des Elektrodenmetalls und der Legierungsbestandteile wird wirksam ausgeschaltet, ohne daß dabei auf die Vorteile des ESU-Verfahrens hinsichtlich einer guten Blockoberfläche, einer metallurgischen Arbeit und die Vermeidung der weißen Flecken verzichtet werden muß.If an inert gas or inert gas atmosphere is used, a pressure of at most 900 mbar can be used. When using vacuum, it is particularly useful to work in a pressure range between 200 and 10⁻² mbar. In all cases there is sufficient degassing of the melt and any oxidation of the electrode metal and the alloy components is effectively eliminated without sacrificing the advantages of the ESR method in terms of a good block surface, metallurgical work and the avoidance of white spots .
Von ganz besonderer Bedeutung ist dabei auch die Schlackezusammensetzung. So ist es z.B. aus der Literatur bekannt, daß aus Schlackenmischungen mit hohen Fluoranteilen infolge der chemischen Reaktionen der Fluorverbindung mit oxidischen Schlackenanteilen laufend gasförmige Fluorverbindungen austreten. Würde man eine derartige Schlacke mit hohen Fluoridanteilen unter Vakuum verwenden, so würde aufgrund der Herabsetzung des Partialdrucks die Reaktion in Richtung auf die Bildung weiterer flüchtiger Fluoride verschoben, so daß der Prozeß schwer kontrollierbar würde.The slag composition is also of particular importance. So it is e.g. known from the literature that gaseous fluorine compounds continuously emerge from slag mixtures with high fluorine fractions due to the chemical reactions of the fluorine compound with oxidic slag fractions. If such a slag with high fluoride contents were used under vacuum, the reaction would be shifted towards the formation of further volatile fluorides due to the lowering of the partial pressure, so that the process would be difficult to control.
Wenn man erfindungsgemäß eine Schlacke verwendet, die zu mindestens 80 Gewichtsprozent aus oxidischen Komponenten besteht, deren Siedepunkte über 2000 °C liegen, so bleibt die Schlackezusammensetzung stabil. In Frage kommen insbesondere reine Oxid-Systeme wie beispielsweise solche aus CaO, Al₂O₃ und MgO. Mit besonderem Vorteil können dabei CaO und Al₂O₃ zu je 48 % und MgO zu 4 Gewichtsprozent vorhanden sein.If, according to the invention, a slag is used which consists of at least 80 percent by weight of oxidic components whose boiling points are above 2000 ° C., the slag composition remains stable. Pure oxide systems such as, for example, come into question CaO, Al₂O₃ and MgO. It can be particularly advantageous to have CaO and Al₂O₃ at 48% each and MgO at 4% by weight.
Die Vorteile des erfindungsgemäßen Verfahrens lassen sich wie folgt darstellen:
- 1. Anwendung von Wechselstrom zur besseren Steuerung der gewünschten metallurgischen Reaktionen und zur Vermeidung von gleichgerichteten Magnetfeldern, die die Pünktchenbildung im Umschmelzblock begünstigen würden,
- 2. Anwendung des Vakuums zur Beseitigung der Einflüsse von Wasserstoff und Stickstoff sowie zur Vermeidung der Oxidation von Schlacke und Metall,
- 3. Anwendung einer oxidischen, reaktionsfähigen Schlacke zur Erzielung eines besseren Reinheitsgrades als beim VAR-Verfahren und
- 4. Vermeidung von weißen Flecken.
- 1. Use of alternating current to better control the desired metallurgical reactions and to avoid rectified magnetic fields which would favor the formation of dots in the remelting block,
- 2. Use of the vacuum to remove the influences of hydrogen and nitrogen and to avoid the oxidation of slag and metal,
- 3. Use of an oxidic, reactive slag to achieve a better degree of purity than with the VAR process and
- 4. Avoid white spots.
Eine Abschmelzelektrode aus Inconel 718, eine Nickel-Basis-Legierung mit hohen Gehalten an Titan und Aluminium, und mit einer Länge von 500 mm und einem Durchmesser von 90 mm wurde in einer wassergekühlten Standkokille mit einem Innendurchmesser von 150 mm zu einem Block umgeschmolzen. Die Höhe des Schlackenbades über dem Block betrug 70 mm. Die Schlacke bestand zu je 48 Gewichtsprozent aus CaO und Al₂O₃ und zu 4 Gewichtsprozent aus MgO. Die Elektrode wurde mit einer Spannung von 35 V und einer Stromstärke von 2300 A betrieben. Nach einer Umschmelzdauer von 15 Minuten unter einem Vakuum von 5 x 10⁻¹ mbar war die Elektrode bis auf einen Rest abgeschmolzen. Der nach Abkühlung aus der Kokille entnommene Block hatte eine saubere glatte Oberfläche und besaß keinerlei "Krone". Schnittbilder ergaben, daß der Block über seine gesamte Länge und seinen gesamten Durchmesser frei von Pünktchen weißen Flecken und Ringmustern war. Die Legierungszusammensetzung entsprach äußerst weitgehend derjenigen der Elektrode, d.h. es wurde keinerlei Abbrand von Aluminium und Titan beobachtet.A melting electrode made of Inconel 718, a nickel-based alloy with a high content of titanium and aluminum, and with a length of 500 mm and a diameter of 90 mm, was remelted into a block in a water-cooled stand mold with an inner diameter of 150 mm. The height of the slag bath above the block was 70 mm. The slag consisted of 48 percent by weight of CaO and Al₂O₃ and 4 percent by weight of MgO. The electrode was operated with a voltage of 35 V and a current of 2300 A. operated. After a remelting period of 15 minutes under a vacuum of 5 x 10⁻¹ mbar, the electrode was melted down to the remainder. The block removed from the mold after cooling had a clean, smooth surface and had no "crown". Cross-sectional images showed that the block was free of dots of white spots and ring patterns over its entire length and its entire diameter. The alloy composition corresponded largely to that of the electrode, ie no erosion of aluminum and titanium was observed.
Claims (4)
- Process for the electroslag remelting of metals, which are remelted in the form of at least one live melting electrode through a molten slag bath under sub-atmospheric pressure to form a block, the slag being heated by means of alternating current, characterised in that the melting electrode, of which there is at least one, consists of a nickel-containing superalloy, which in addition to nickel contains at least one de-oxygenated alloy component from the group of elements aluminium, boron, titanium and zirconium, and in that, as slag, an oxidic slag of at least 80 per cent by weight is used, composed of such oxides, whose boiling points are above 2000°C.
- Process according to claim 1, characterised in that a vacuum of between 200 and 10⁻² mbar is selected.
- Process according to claim 1, characterised in that the remelting process is carried out in an inert gas atmosphere at a pressure of at most 900 mbar.
- Process according to claim 1, characterised in that the frequency of the alternating current is between 1 and 100 Hz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT87107038T ATE65551T1 (en) | 1986-06-07 | 1987-05-15 | METHOD FOR ELECTRIC SLAG REMELTING OF METALS, ESPECIALLY THOSE WITH OXYGEN-AFFINED ALLOY COMPONENTS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3619293A DE3619293C2 (en) | 1986-06-07 | 1986-06-07 | Process for electroslag remelting of metals, in particular those with alloy components with affinity for oxygen |
| DE3619293 | 1986-06-07 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0249050A1 EP0249050A1 (en) | 1987-12-16 |
| EP0249050B1 true EP0249050B1 (en) | 1991-07-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87107038A Expired - Lifetime EP0249050B1 (en) | 1986-06-07 | 1987-05-15 | Process for the electroslag refining of metals, especially of such metals containing components with a high oxygen affinity |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4726840A (en) |
| EP (1) | EP0249050B1 (en) |
| JP (1) | JP2588895B2 (en) |
| AT (1) | ATE65551T1 (en) |
| DE (2) | DE3619293C2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5332197A (en) * | 1992-11-02 | 1994-07-26 | General Electric Company | Electroslag refining or titanium to achieve low nitrogen |
| GB2302551B (en) * | 1995-06-22 | 1998-09-16 | Firth Rixson Superalloys Ltd | Improvements in or relating to alloys |
| CA2306672A1 (en) * | 1997-10-22 | 1999-04-29 | General Electric Company | Method for dissolution of nitrogen-rich inclusions in titanium and titanium alloys |
| US6113666A (en) * | 1998-08-11 | 2000-09-05 | Jaroslav Yurievich Kompan | Method of magnetically-controllable, electroslag melting of titanium and titanium-based alloys, and apparatus for carrying out same |
| JP2003523831A (en) * | 2000-02-23 | 2003-08-12 | ゼネラル・エレクトリック・カンパニイ | Nucleation casting apparatus and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1483646A1 (en) * | 1965-06-11 | 1969-09-25 | Suedwestfalen Ag Stahlwerke | Method and device for the production of cast blocks, preferably steel blocks |
| BE795856A (en) * | 1972-02-24 | 1973-08-23 | Air Liquide | IMPROVEMENT OF THE ELECTRIC REFINING PROCESS BY DAIRY CALLED "E.S.R. PROCESS" |
| GB1374149A (en) * | 1972-03-24 | 1974-11-13 | British Iron Steel Research | Electroslag refining apparatus |
| US3759311A (en) * | 1972-04-04 | 1973-09-18 | Allegheny Ludlum Steel | Arc slag melting |
| US4117253A (en) | 1977-03-01 | 1978-09-26 | Wooding Corporation | High integrity atmosphere control of electroslag melting |
-
1986
- 1986-06-07 DE DE3619293A patent/DE3619293C2/en not_active Expired - Fee Related
- 1986-08-15 US US06/896,937 patent/US4726840A/en not_active Expired - Lifetime
-
1987
- 1987-05-15 DE DE8787107038T patent/DE3771586D1/en not_active Expired - Lifetime
- 1987-05-15 AT AT87107038T patent/ATE65551T1/en not_active IP Right Cessation
- 1987-05-15 EP EP87107038A patent/EP0249050B1/en not_active Expired - Lifetime
- 1987-06-04 JP JP62139091A patent/JP2588895B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63259031A (en) | 1988-10-26 |
| US4726840A (en) | 1988-02-23 |
| DE3771586D1 (en) | 1991-08-29 |
| DE3619293C2 (en) | 1993-10-14 |
| ATE65551T1 (en) | 1991-08-15 |
| DE3619293A1 (en) | 1987-12-10 |
| JP2588895B2 (en) | 1997-03-12 |
| EP0249050A1 (en) | 1987-12-16 |
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