US3759700A - Process of refining metal melts by supersonic oxygen blow - Google Patents

Process of refining metal melts by supersonic oxygen blow Download PDF

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Publication number
US3759700A
US3759700A US00004917A US3759700DA US3759700A US 3759700 A US3759700 A US 3759700A US 00004917 A US00004917 A US 00004917A US 3759700D A US3759700D A US 3759700DA US 3759700 A US3759700 A US 3759700A
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Prior art keywords
oxygen
melt
melts
lance
jet
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Expired - Lifetime
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US00004917A
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English (en)
Inventor
A Diener
H Kutscher
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Fried Krupp AG Hoesch Krupp
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Hoesch AG
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum

Definitions

  • This invention relates to a process for refining molten metals, particularly iron melts and steel melts, in which for example thelcarbon content and/or the content of other undesiredlelements in the metal is reduced.
  • the invention also relates to apparatus for carrying out the process.
  • German patent specification (Auslegeschrift) 1,216,904 describes a process for degassing a melt at greatly reduced pressure, in which the melt flows through a vacuum chamber situated above the body of melt which it is desired to degas.
  • the molten metal is introduced into the vacuum chamber through an inlet pipe by means of a conveying gas.
  • the vacuum vessel is arranged to move up and down to discharge degassed portions of the melt and draw in fresh portions of melt for degassing, the vessel being connected to the melt by a length of pipe whose lower end dips into the melt.
  • oxygen is blown at supersonic velocity onto the surface of a melt under reduced pressure in a vacuum chamber.
  • pure oxygen can be introduced into the melt in a vacuum chamber so that the resulting high heat of reaction of the oxidation reaction is utilized and high alloy melts can be produced, without the disadvantages mentioned earlier.
  • the oxygen jet forms a cohesive narrow column of flowing gas which does not escape through the vacuum pump before reacting with the metal melt. Consequently, the oxygen reacts practically completely with the easily oxidized substances in the metal melt, for example with the carbon in an iron or steel melt.
  • the pressure of the oxygen jet at the point it enters the vacuum chamber is below, but not too far below, the internal pressure in the vacuum chamber, otherwise there would result a very short supersonic jet which would break down at the first node by shock compression to give a useless subsonic jet.
  • the pressure in the oxygen jet at the nozzle outlet is not too different from the pressure in the vacuum vessel there is formed an elongated supersonic jet which is stable through several nodes. If the pressure in the jet at the nozzle outlet is much higher than the pressure in the vacuum vessel, the jet bursts just after leaving the nozzle, and becomes useless.
  • apparatus for performing a process according to the invention comprises a vacuum chamber, means for evacuating the chamber, and an oxygen lance which projects into the chamber and which is capable of directing a jet of oxygen at supersonic velocity onto the surface of a melt which in operation is contained in the chamber.
  • the outlet opening at the end of the lance is preferably constructed as a Laval nozzle.
  • the lance is preferably arranged so that it can be retracted into the connection through which it passes into the vacuum chamber, and there is a member which is movable to close the mouth of the connection when the lance is retracted so that the outlet end of the lance is protected when not in use. This protects the end of the lance, especially when this is a Laval nozzle, from spattered metal and slag.
  • FIG. 1 is a vertical section through one example comprising a vacuum enclosure in which there rests a pan containing a metal melt;
  • FIG. 2 is a vertical section through the second example showing a vacuum lifting vessel having a lower suction pipe dipping into a metal melt in a pan, the figure showing the apparatus during the refining of a portion of the melt;
  • FIG. 3 is a similar view to FIG. 2, but shows the apparatus during discharging of the refined portion of the melt back into the pan.
  • the apparatus shown in FIG. 1 consists of a vacuum enclosure 5 closed by a gas-tight cover 6 fitted with a connection 8 leading to a vacuum pump 7 (not shown).
  • the cover 6 also has a connection 9 with a stuffing box seal 10 through which there passes, in a gas-tight but axially slidable fashion, an oxygen lance 11.
  • the outlet opening of the oxygen lance 11 is in the form of 2.
  • Laval nozzle 12 which causes the oxygen which issues from the lance to form a narrow, cohesive jet. Beneath the nozzle 12 of the oxygen lance 11 there is a pan 13 containing the metal melt 14 which is being processed.
  • the lance 11 is not in use it is retracted upwards into the neck of the connection 9 and covered over by a flap 15, for protection against spattered metal and slag. This is particularly to protect the Laval nozzle 12.
  • a vacuum lifting vessel 18 has a lower suction pipe 17 which dips into a metal melt 20 contained in a pan 19.
  • the vacuum vessel 18 is connected by a connection 21 to a vacuum pump, not shown in the drawing, and also has an inlet connected to a feed device 22 for introducing alloy substances into the melt.
  • the upper end of the vacuum vessel 18 is equipped with a lance connection 23 containing a stufiing box seal 24 through which an oxygen lance 25 passes in a gas-tight but axially slidable fashion.
  • the lance 25 has its outlet opening in the form of a Laval nozzle 26.
  • the vacuum lifting vessel 18 is also equipped with an internal flap 27 for protecting the nozzle 26 of the oxygen lance 25 when the lance is retracted and not in use.
  • the arrangement illustrated in FIGS. 2 and 3 is operated intermittently, that is to say oxygen is blown only during the degassing part of the process, which is the period when a portion of the melt 20 is being lifted under vacuum, and degassed, in the degassing vessel 18. This arrangement during this part of the process is represented in FIG. 2.
  • no oxygen is blown when the degassed and refined portion of melt is run down again into the pan 19, as is represented in FIG. 3.
  • the lance 25 has a shut-otf valve 28, which can if desired be controlled by the lifting mechanism for the vacuum vessel 18, the vessel being lifted in order to cause the degassed portion of the melt to run back into the pan 19.
  • a steel melt containing 0.3% carbon, 16% chromium and 8% nickel was refined in vacuo at a pan temperature of 1650" C., the amount of carbon in the melt being reduced to 0.03% with practically no slagging of the chromium. It should be noted that at this temperature the oxygen dissolved in the melt could not have reduced the amount of carbon to less than 0.25%.
  • This arrangement provided a supersonic oxygen jet with a pressure of 15 torr at the nozzle outlet, this pressure being less than the pressure prevailing in the vacuum vessel 18 which was 20 torr.
  • the supersonic jet took the form of a cohesive narrow jet directed onto the portion of the melt in the vessel 18 and this rapidly caused the removal of carbon from the melt.
  • a process of refining metal melts, particularly iron and steel melts, in a vacuum chamber including the steps of supplying at least a portion of said melt to said vacuum chamber, reducing the pressure in said chamber, and blowing from a Laval nozzle onto the surface of said melt in said vacuum chamber a narrow cohesive jet of oxygen at supersonic velocity which substantially entirely impinges on the surface of the melt, and controlling said blowing whereby the pressure of said oxygen jet at the point where said jet enters said vacuum chamber is about 25% lower than said pressure in said vacuum chamber.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
US00004917A 1969-01-30 1970-01-22 Process of refining metal melts by supersonic oxygen blow Expired - Lifetime US3759700A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691904442 DE1904442B2 (de) 1969-01-30 1969-01-30 Verfahren zum vakuumfrischen von metallschmelzen

Publications (1)

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US3759700A true US3759700A (en) 1973-09-18

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US00004917A Expired - Lifetime US3759700A (en) 1969-01-30 1970-01-22 Process of refining metal melts by supersonic oxygen blow

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US (1) US3759700A (enrdf_load_stackoverflow)
JP (1) JPS543121B1 (enrdf_load_stackoverflow)
DE (1) DE1904442B2 (enrdf_load_stackoverflow)
FR (1) FR2029665B1 (enrdf_load_stackoverflow)
GB (1) GB1288336A (enrdf_load_stackoverflow)
SE (1) SE363846B (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0584814A3 (en) * 1992-08-26 1994-09-07 Nippon Steel Corp Process and apparatus for vacuum degassing molten steel

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL155487B (nl) * 1965-07-22 1978-01-16 Textron Inc Vulpen of dergelijk schrijf- of markeerinstrument.
JPS5442211A (en) * 1977-09-09 1979-04-04 Yoshio Midorikawa Feltttip pen and method and device for making said pen
HU179333B (en) * 1978-10-04 1982-09-28 Vasipari Kutato Intezet Method and apparatus for decreasing the unclusion contents and refining the structure of steels
EP0328851A1 (en) * 1988-02-16 1989-08-23 Acciaierie E Ferriere Lombarde Falck S.P.A. An apparatus for decarbonizing steels directly in the ladle
CA1337846C (en) * 1988-06-21 1996-01-02 Hiroshi Nishikawa Process for vacuum degassing and decarbonization with temperature drop compensating feature
DE4442362C1 (de) * 1994-11-18 1996-04-18 Mannesmann Ag Verfahren und Vorrichtung zum Behandeln von einer in einem metallurgischen Gefäß befindlichen Metallschmelze

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2093666A (en) * 1934-11-23 1937-09-21 Wacker Chemie Gmbh Process for treating iron and iron alloys
AT174069B (de) * 1950-01-31 1953-02-25 Voest Ag Verfahren zur Herstellung von technisch reinem Eisen
DE975922C (de) * 1951-03-17 1962-12-13 Oesterr Alpine Montan Verfahren zum Verblasen von Roheisen, bei welchem Sauerstoff mit einer Blasduese von oben auf die Badoberflaeche aufgeblasen wird
GB761657A (en) * 1953-01-15 1956-11-21 Oesterr Alpine Montan Improvements in methods for blowing metal baths, particularly pig iron baths
DE1216904B (de) * 1957-04-03 1966-05-18 Heraeus Gmbh W C Verfahren zum Vakuumentgasen von geschmolzenen Metallen, insbesondere Stahl
DE1804748U (de) * 1958-02-22 1960-01-28 Hoerder Huettenunion Ag Vorrichtung zum entgasen von stahlschmelzen.
FR1238058A (fr) * 1958-10-11 1960-08-05 Suedwestfalen Ag Stahlwerke Procédé pour l'obtention de bains de fusion de métaux fortement alliés
DE1194886B (de) * 1960-06-24 1965-06-16 Beteiligungs & Patentverw Gmbh Verfahren zum Frischen von Roheisen, insbesondere solchem mit hohem Phosphorgehalt
FR1277441A (fr) * 1960-10-22 1961-12-01 Siderurgie Fse Inst Rech Perfectionnements au traitement de l'acier sous vide
GB1027115A (en) * 1963-06-25 1966-04-20 Allegheny Ludlum Steel Improvements in or relating to a process for producing corrosion-resisting steel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0584814A3 (en) * 1992-08-26 1994-09-07 Nippon Steel Corp Process and apparatus for vacuum degassing molten steel
US5413623A (en) * 1992-08-26 1995-05-09 Nippon Steel Corporation Process and apparatus for vacuum degassing molten steel

Also Published As

Publication number Publication date
SE363846B (enrdf_load_stackoverflow) 1974-02-04
GB1288336A (enrdf_load_stackoverflow) 1972-09-06
DE1904442A1 (de) 1970-09-03
FR2029665A1 (enrdf_load_stackoverflow) 1970-10-23
JPS543121B1 (enrdf_load_stackoverflow) 1979-02-19
DE1904442B2 (de) 1978-01-19
FR2029665B1 (enrdf_load_stackoverflow) 1974-08-09

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