US3306731A - Method of degassing steel - Google Patents

Method of degassing steel Download PDF

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Publication number
US3306731A
US3306731A US412206A US41220664A US3306731A US 3306731 A US3306731 A US 3306731A US 412206 A US412206 A US 412206A US 41220664 A US41220664 A US 41220664A US 3306731 A US3306731 A US 3306731A
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United States
Prior art keywords
chamber
steel
vacuum
degasification
pressure
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Expired - Lifetime
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US412206A
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English (en)
Inventor
Messing Theodor
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STANDARD MESSO GES fur CHEMIET
Standard-Messo Gesellschaft fur Chemietechnik Mbh & Co
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STANDARD MESSO GES fur CHEMIET
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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 reduction in pressure for causing molten steel to give off gas does not, however, ordinarily yield a degasification corresponding to the pressure, because the principles of diffusion principally determine the quantity of gas which is to be given off during the period during which the vacuum treatment takes place. Accordingly, the yield of gas at a certain predetermined vacuum is dependent primarily on the time period of treatment and on the length of the path over which the gas has to move within the steel melt up to the steel surface which yields the gas.
  • the steel which is poured from the pouring ladle into an intermediate ladle mounted On a vacuum container is for purposes of pre-degasification passed into a chamber from which it is subsequently with a certain predetermined loss in pressure poured in a vacuum of desired magnitude into the ingot mold in a vacuum container to thereby bring about a degasification of the steel.
  • an additional gas may be blown into the chamber from the outside.
  • An apparatus for practicing the method according to the present invention consists primarily of a degasification device known per se for degasifying the pouring jet and comprises an intermediate ladle arranged on the vacuum contatiner for receiving the ingot mold, the intert mediate ladle being supplemented by an additional chamber.
  • This chamber is arranged in the vacuum container above the ingot mold and communicates with the interior of the intermediate ladle through an opening therein.
  • This chamber is lined with refractory material and is connected to the container lid preferably by holding means.
  • the drawing shows a degasifying arrangement known per se for degasifying a pouring jet.
  • vacuum container 1 having an ingot mold 2 arranged on support 8 and being closed air-tight by a container cover 5.
  • the arrangement furthermore comprises an intermediate ladle 3 which is mounted above the vacuum container 1.
  • the intermediate ladle 3 is filled with molten steel by means of a main ladle 13.
  • the intermediate ladle 3 communicates with the interior of vacuum container 1 through a bottom-pour opening 11 which is adapted to be closed by a plug 10.
  • the vacuum in the interior of said vacuum container 1 is produced and maintained by suction pumps (not shown) which are connected to the vacuum container 1 through the intervention of a suction pipe 6.
  • the vacuum container 1 is above the ingot mold 2 provided with an additional chamber 4 which communicates with the intermediate ladle 3 through the bottom-pour opening 11 of said intermediate ladle.
  • Chamber 4 is by holding means 7 connected to container cover and has a discharge opening 12 which is greater in diameter than the bottom-pour opening 11.
  • a gas pipe 14 leads into chamber 4 in order to permit the supply of inert gas from the outside into chamber 4 for purpose of making up for the loss in pressure therein.
  • chamber 4 consists in receiving the steel which passes from the intermediate ladle 3 into vacuum container 1 and also to permit this steel to pass into ladle 2.
  • the dimensions of the cross sections through which the steel passes are so selected that when the steel passes through the respective openings, a certain preselected resistance will be encountered and thus a certain preselected drop in pressure.
  • the discharge opening 12 of chamber 4 is larger than the bottom-pour opening 11. In this connection, however, care has to be taken that the discharge opening 12 of chamber 4 be selected so small that the flowing steel including the pre-degasified gas ingredients will be able to produce a pressure drop in conformity with the well known laws governing the flow of liquids.
  • This arrangement comprises a additional flow of said inert gas will be able to vary the said resistance and thus the pressure to the desired extent.
  • the steel is poured from main ladle 13 into intermediate ladle 3 from which, after plug 10 has been opened, it passes through the bottom-pour opening 11 into vacuum container 1.
  • vacuum container 1 the steel first enters the auxiliary chamber 4 in which only at the start of the pouring operation the vacuum will be the same as in the ingot mold 2 and in vacuum container 1. While the discharge opening 12 of chamber 4 is larger than the bottom-pour opening 11 so that the steel can pass from chamber 3 through chamber 4 without backing up, opening 12 is still small enough to produce a loss in pressure.
  • an own pressure will prevail in chamber 4 with regard to the higher vacuum, and this overpressure may be controlled for instance by means of a quantity of foreign gas.
  • the method according to the present invention yields the known advantages of the degasification of pouring jets and the favorable effect of a high vacuum without the necessity of considering the gas content of the steel and the pouring speed.
  • the low pressure in the vacuum container is produced by steam jet vacuum pumps of high suction output and is maintained during all phases of the vacuum treatment.
  • the atomizing effect of the outfiowing steel is avoided.
  • the degasifying effect according to the present invention is aided by the fact that in view of chamber 4, depending on the liquid content of this chamber, the total dropping time of the steel is increased whereby the diffusion is favorably affected.
  • the steel was molten in an electric arc furnace by the two-slag practice, the steel being completely killed. Its composition was as follows: 035% C; 0.26% Si; 0.59% Mn; 1.14% Cr; 0.21% Mo.
  • the diameter of the discharge opening of the intermediate ladle 11 was 40 mm.; that of the discharge opening of the'chamber 12 was 45 mm. Depending on the temperature and the composition of the steel, the increase of discharge opening diameters during operation will differ in size, a fact which should be considered when determining those diameters.
  • the vacuum at the beginning of the pouring operation was 0.1 millimeter mercury in both the vacuum chamber 4 and in the chamber 12. During the pouring operation the following average vacuum values were ascertained:
  • Vacuum block tons 70 Diameter of discharge opening of the intermediate ladle mm 40 Diameter of discharge opening of the chamber mm 50 During the vacuum treatment the following pressures were ascertained.
  • a method of stepwise degasifying molten metal, especially molten steel, by pouring the metal to be degasified successively into a first chamber for pre-degasification in a vacuum and from said first chamber into a second chamber for post-degasification in a vacuum which includes the steps of: introducing the molten metal into said first chamber so that the stream of metal will be torn apart into droplets while maintaining the vacuum in said first chamber lower than that in said second chamber and within desired limits by introducing a gas from the outside into said first chamber, and subsequently passing the thus pre-degasified metal in a continuous and coherent stream into said second chamber for post-degasification at the higher vacuum prevailing therein.

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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)
US412206A 1963-11-20 1964-11-18 Method of degassing steel Expired - Lifetime US3306731A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEST21343A DE1228291B (de) 1963-11-20 1963-11-20 Verfahren und Vorrichtung zum nachtraeglichen Entgasen geschmolzener Staehle

Publications (1)

Publication Number Publication Date
US3306731A true US3306731A (en) 1967-02-28

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ID=7458960

Family Applications (1)

Application Number Title Priority Date Filing Date
US412206A Expired - Lifetime US3306731A (en) 1963-11-20 1964-11-18 Method of degassing steel

Country Status (7)

Country Link
US (1) US3306731A (xx)
AT (1) AT261652B (xx)
BE (1) BE655523A (xx)
DE (1) DE1228291B (xx)
ES (1) ES305193A1 (xx)
GB (1) GB1092051A (xx)
NL (1) NL143991B (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3367396A (en) * 1965-04-05 1968-02-06 Heppenstall Co Installation for the vacuum treatment of melts, in particular steel melts, and process for its operation
US3408059A (en) * 1965-06-02 1968-10-29 United States Steel Corp Apparatus for stream degassing molten metal
US3417463A (en) * 1965-07-09 1968-12-24 Maximilianshuette Eisenwerk Method of producing steel for sheets to be enamelled by the single-coat method
US4584015A (en) * 1983-09-26 1986-04-22 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Process and system for the production of very pure alloys

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2882570A (en) * 1956-05-22 1959-04-21 Joseph B Brennan Continuous vacuum casting
CA613169A (en) * 1961-01-24 Coupette Werner Process for the effective degasification and deoxidation of steel
US3013316A (en) * 1958-12-31 1961-12-19 United States Steel Corp Method and apparatus for vacuum casting
US3071458A (en) * 1960-05-09 1963-01-01 Finkl & Sons Co Method of adding charge material to molten metal under vacuum

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA613169A (en) * 1961-01-24 Coupette Werner Process for the effective degasification and deoxidation of steel
US2882570A (en) * 1956-05-22 1959-04-21 Joseph B Brennan Continuous vacuum casting
US3013316A (en) * 1958-12-31 1961-12-19 United States Steel Corp Method and apparatus for vacuum casting
US3071458A (en) * 1960-05-09 1963-01-01 Finkl & Sons Co Method of adding charge material to molten metal under vacuum

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3367396A (en) * 1965-04-05 1968-02-06 Heppenstall Co Installation for the vacuum treatment of melts, in particular steel melts, and process for its operation
US3408059A (en) * 1965-06-02 1968-10-29 United States Steel Corp Apparatus for stream degassing molten metal
US3417463A (en) * 1965-07-09 1968-12-24 Maximilianshuette Eisenwerk Method of producing steel for sheets to be enamelled by the single-coat method
US4584015A (en) * 1983-09-26 1986-04-22 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Process and system for the production of very pure alloys

Also Published As

Publication number Publication date
NL143991B (nl) 1974-11-15
AT261652B (de) 1968-05-10
NL6412483A (xx) 1965-05-21
ES305193A1 (es) 1965-01-01
DE1228291B (de) 1966-11-10
GB1092051A (en) 1967-11-22
BE655523A (xx) 1965-03-01

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