US3033550A - Treatment of metal melts - Google Patents

Treatment of metal melts Download PDF

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Publication number
US3033550A
US3033550A US806554A US80655459A US3033550A US 3033550 A US3033550 A US 3033550A US 806554 A US806554 A US 806554A US 80655459 A US80655459 A US 80655459A US 3033550 A US3033550 A US 3033550A
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United States
Prior art keywords
vessel
rising pipe
pipe
gas
melt
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Expired - Lifetime
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US806554A
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English (en)
Inventor
Harders Fritz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dortmund Hoerder Huettenunion AG
Original Assignee
Dortmund Hoerder Huettenunion 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

  • the apparatus must be designed in sucha way that the evacuatable vessel is disposed at only a small distance above the container which is under atmospheric pressure, and it must be borne in mind that the container frequently consists of a ladle filled with a melt and otherwise designed from the usual points of view. For these and other reasons it has not been possible to increase the amount of melt in the evacuated vessel above a certain amount which is in no way sufficient.
  • the invention is based on the discovery that the dynamic buoyancy produced by the current of gas flowing upwardly in the rising pipe is such as to be practically useful only if the current of gas is introduced in such a way that it is distributed over the entire cross-sectional area of the rising pipe. If the process is carried out in this way it has been surprisingly discovered that even relatively small amounts of gas, which have no appreciable eifect when the known method is used, effect a considerable raising of the level of the melt in the vacuum vessel. The explanation of this unexpected effect is probably that a current of gas which is not distributed over the full cross-section of the rising pipe only causes turbulence in the rising pipe but not buoyancy.
  • An apparatus for carrying the process of the invention into effect can be constructed in many different forms.
  • the most obvious way is to insert a large number of nozzles through the wall of the rising pipe, the nozzles projecting to different distances from the wall. This, however, would lead to structural complications which could scarcely be overcome. It would also be possible to construct a part of the wall of the rising pipe of porous refractory brickwork through which the gas is blown.
  • a sufficient tine distribution of the gas current is obtained if the cross-section of an individual nozzle is, at the most, equal to 1 mm. In this case excellent results are obtained particularly if the nozzle head is made of refractory porous material.
  • the shape of the nozzle head in other respects it is advisable to make it conform in shape and size to the internal cross-sectional area of the rising pipe.
  • the upward flow of the melt is not interfered with by the nozzle head arranged below the mouth of the rising pipe if the distance between the mouths of the rising pipe and of the gas inlet pipe is made approximately equal to or greater than'the internal diameter of the rising pipe. The effect of the flow is then to hold together the rising streams of gas bubbles.
  • the degasified melt in the vacuum vessel is returned through the rising pipe to a ladle or container below it.
  • the nozzle head disposed below the mouth of the rising pipe may cause some interference. Since the uniformity of a vacuum treatment depends on -whether the degasified material can mix completely with the metal in the ladle,
  • the degasified material on its return to the ladle flows to the bottom thereof in a substantially closed stream and first distributes itself over the bottom so that mixing then takesplace from the bottom upwards.
  • the gas inlet pipe and its month are so arranged that they can be moved out of alignment with the rising pipe, for example by mounting the gas inlet pipe so that it can be swung aside.
  • the apparatus illustrated consists of a lower ladle 1 which is under atmospheric pressure and is provided with the usual closure plug and with a refractory lining 2, and an upper vessel 3 which has a refractory lining 4 and can be closed on all sides and is connected by a pipe 5 to a vacuum pump.
  • the vessel 3 has a cover 6 having a closable opening 7 through which other substances can, if necessary, be added in regulated quantity to the melt in the vessel 3.
  • the ladle 1 and the vessel 3 are in communication through a rising pipe 8 which is protected on the inside and partly also on the outside by a refractory lining 1t and a refractory jacket 9.
  • a curved pipe 11 extends into the container 1 and is suspended from a support 12.
  • the support 12 allows the pipe 11 to be swung about a vertical axis 13 and also permits its height to be adjusted.
  • the pipe 11, which is protected by a refractory covering 14 is provided at its lower open end with a hollow member 15 of porous brick or stone which is disposed in alignment with and below the opening of the rising pipe 8.
  • the pipe 11 is connected, by means not illustrated, to a vessel containing gas under pressure.
  • the steel to be degasified is charged up to the level a into the ladle 1.
  • the vacuum pump connected to the pipe 5 is switched on, so that the vacuum produced in the vessel 3 draws part of the steel from the ladle 1 into the vessel 3, whereby the level in the ladle is lowered to the level [1.
  • the distance between the levels of the melt in the ladle 1 and in the vessel 3 now amounts to h;, an amount which cannot be greater than the barometric height which, in the case of iron, only amounts on the average to 1.4 metres.
  • a valve which is not illustrated and is disposed between the pressure gas container and the pipe 11 is opened so that gas emerges in a finely divided form from the outer surface 17 of the member 15.
  • the gas bubbles which are indicated by dots in the drawing rise in the melt and arrive at the mouth 16 of the rising pipe 8 and then rise upwards in the pipe 8 until they arrive in the gas chamber of the vacuum vessel 3.
  • This current of gas which is produced in the form of finely distributed bubbles produces a dynamic buoyancy, the result of which is that the distance between the level of the melt in the ladle and in the vacuum vessel rises from the original mount I1 determined by the barometric height to the amount I1 and the level in the ladlevsinks to c.
  • the drawing shows clearly the extent to which the amount of melt in the vessel 3 is thereby increased.
  • the vacuum is disconnected so that the melt in the vessel 3 is returned to the ladle 1.
  • the gas pipe 11 is previously swung laterally about the axis 13-, so that the nozzle head 15 is disposed outside the extended axis of the rising pipe 8'.
  • the interchange of the portions of the melt in the vacuum vessel 3 with portions in the ladle 1 need not be effected by alternately connecting the disconnecting the vacuum at 5. Instead of doing this it is possible to increase and reduce the distance between the vessel '3 and the ladle 1, that is to say to raise and lower either the vacuum vessel 3 or the ladle 1. Then, in all cases, when the vessel 3 is emptied into the ladle 1 through the rising pipe 8 the head 15 is swung aside. In the reverse process when the melt is returned through the rising pipe 8 into the vacuum vessel 3 the nozzle head 15 can at first remain in its swung aside position. However, in order to effect a more rapid charging of the vessel it is usually advantaigeous to bring the nozzle head 15 into its swung-in position in alignment with the rising pipe 8 at the same time as the inflow into the vessel 3 begins.
  • the current of gas which escapes through the pores in the nozzle 15 can, and should in general, be maintained, in order that the pores may not be blocked by parts of the melt.
  • the steel which flows from below into the rising pipe may, in some circumstances, have a restrictive and compressive effect on the gas bubbles in the cross-sectional area. If the uniformity of the distribution of the current of gas is too strongly impaired in this way, then additional gas can'be introduced from the inner surface of the pipe, so that a sufiicient number of gas bubbles also rise up in the edge zone and prevent the liquid steel from flowing back in this zone.
  • Apparatus for the vacuum treatment of metal melt comprising a closed vessel, means for evacuating said vessel, a container for the melt disposed below said vessel and under atmospheric pressure, a rising pipe forming the sole connection between said vessel and said container, the upper end of said pipe being connected to said vessel and the lower open end extending into said container, and a gas inlet pipe with its outlet disposed below, in alignment with, and spaced from the lower open end of said rising pipe, said gas inlet pipe having a plurality of outlet nozzles of small size relative to the cross-sectional area of said rising pipe, said nozzles being uniformly distributed over an area the shape and size of which equals substantially that of the internal cross-sectional area of said rising pipe, whereby the gas is distributed over the crosssectional area of said rising pipe.

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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)
  • Manufacture And Refinement Of Metals (AREA)
US806554A 1958-05-22 1959-04-15 Treatment of metal melts Expired - Lifetime US3033550A (en)

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Application Number Priority Date Filing Date Title
DE3033550X 1958-05-22

Publications (1)

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US3033550A true US3033550A (en) 1962-05-08

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US (1) US3033550A (en))
FR (1) FR1222937A (en))
GB (1) GB893014A (en))
LU (1) LU36886A1 (en))
NL (1) NL121353C (en))

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3501289A (en) * 1965-06-09 1970-03-17 Finkl & Sons Co Method and apparatus for adding heat to molten metal under vacuum
US3565412A (en) * 1968-12-03 1971-02-23 Dresser Ind Device for stirring molten metal
US3799522A (en) * 1971-10-08 1974-03-26 British Aluminium Co Ltd Apparatus for introducing gas into liquid metal
US3887172A (en) * 1972-03-08 1975-06-03 Arbed Apparatus for the treatment of a molten metal bath
US4148468A (en) * 1977-03-03 1979-04-10 Messer Griesheim Gmbh Lance for the flush gas treatment of non-ferrous molten metals
US4179103A (en) * 1977-02-10 1979-12-18 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Means for injecting gas into a molten metal
US4647272A (en) * 1980-11-20 1987-03-03 Aluminum Company Of America Method and lift pump for raising liquids
US4791978A (en) * 1987-11-25 1988-12-20 Vesuvius Crucible Company Gas permeable stopper rod
US5603749A (en) * 1995-03-07 1997-02-18 Bethlehem Steel Corporation Apparatus and method for vacuum treating molten steel

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3128324A (en) * 1960-03-22 1964-04-07 Ruhrstahl Huttenwerke Ag Device for the purification of molten steel
GB1281720A (en) * 1968-07-23 1972-07-12 Nippon Kokan Kk A method of improving vacuum treatment of liquid metal

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1921060A (en) * 1931-03-23 1933-08-08 Clyde E Williams Method of purifying metals
US2726952A (en) * 1954-05-05 1955-12-13 Ford Motor Co Method of preparation of iron aluminum alloys
US2848317A (en) * 1955-01-13 1958-08-19 Bochumer Ver Fur Gussstahlfabr Desulfurizing of steel
US2852246A (en) * 1956-02-27 1958-09-16 Janco Nathan Vacuum degassing apparatus
US2854333A (en) * 1957-04-29 1958-09-30 Ethyl Corp Method and apparatus for forming liquid alloys of alkali metals
US2871008A (en) * 1950-11-02 1959-01-27 Air Liquide Apparatus for gas flushing of molten metal
US2893860A (en) * 1957-02-21 1959-07-07 Heraeus Gmbh W C Method and apparatus for continuously degassing molten metals, particularly steel, by evacuation

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1921060A (en) * 1931-03-23 1933-08-08 Clyde E Williams Method of purifying metals
US2871008A (en) * 1950-11-02 1959-01-27 Air Liquide Apparatus for gas flushing of molten metal
US2726952A (en) * 1954-05-05 1955-12-13 Ford Motor Co Method of preparation of iron aluminum alloys
US2848317A (en) * 1955-01-13 1958-08-19 Bochumer Ver Fur Gussstahlfabr Desulfurizing of steel
US2852246A (en) * 1956-02-27 1958-09-16 Janco Nathan Vacuum degassing apparatus
US2893860A (en) * 1957-02-21 1959-07-07 Heraeus Gmbh W C Method and apparatus for continuously degassing molten metals, particularly steel, by evacuation
US2854333A (en) * 1957-04-29 1958-09-30 Ethyl Corp Method and apparatus for forming liquid alloys of alkali metals

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3501289A (en) * 1965-06-09 1970-03-17 Finkl & Sons Co Method and apparatus for adding heat to molten metal under vacuum
US3565412A (en) * 1968-12-03 1971-02-23 Dresser Ind Device for stirring molten metal
US3799522A (en) * 1971-10-08 1974-03-26 British Aluminium Co Ltd Apparatus for introducing gas into liquid metal
US3887172A (en) * 1972-03-08 1975-06-03 Arbed Apparatus for the treatment of a molten metal bath
US4179103A (en) * 1977-02-10 1979-12-18 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Means for injecting gas into a molten metal
US4246216A (en) * 1977-02-10 1981-01-20 L'air Liguide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method for manufacturing a gas delivery device
US4148468A (en) * 1977-03-03 1979-04-10 Messer Griesheim Gmbh Lance for the flush gas treatment of non-ferrous molten metals
US4647272A (en) * 1980-11-20 1987-03-03 Aluminum Company Of America Method and lift pump for raising liquids
US4791978A (en) * 1987-11-25 1988-12-20 Vesuvius Crucible Company Gas permeable stopper rod
US5603749A (en) * 1995-03-07 1997-02-18 Bethlehem Steel Corporation Apparatus and method for vacuum treating molten steel

Also Published As

Publication number Publication date
NL121353C (en))
GB893014A (en) 1962-04-04
LU36886A1 (en))
FR1222937A (fr) 1960-06-14

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