US3189956A - Production of effervescing steel - Google Patents

Production of effervescing steel Download PDF

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Publication number
US3189956A
US3189956A US193243A US19324362A US3189956A US 3189956 A US3189956 A US 3189956A US 193243 A US193243 A US 193243A US 19324362 A US19324362 A US 19324362A US 3189956 A US3189956 A US 3189956A
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Prior art keywords
steel
oxygen
mold
metal
casting
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Expired - Lifetime
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US193243A
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English (en)
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Harold A Longden
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SMS Concast AG
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Concast AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • 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
    • C21C3/00—Manufacture of wrought-iron or wrought-steel
    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing

Definitions

  • This invention relates to the continuous casting of elfervescing steel.
  • Effervescing steel is steel that has deliberately not been completely killed by the addition of one or more deoxidants. It is well known that the steel effervesces in the molds into which it is poured, and in consequence contains blow holes, and it is essential that these should be deep in the steel. If they are at the surface, the steel cannot be rolled saisfactorily.
  • the molds used in continuous casting may be of small cross-sectional area and the casting rate for production reasons may be high.
  • the free liquid surface of metal in the mold through which the gases must escape is low in relation to the volume of gases evolved and the metal becomes very turbulent and thus particularly liable to overiiow.
  • the principal object of this invention is so to cast effervescing steel continuously as to ensure that the blow holes are buried deep in the steel.
  • Another object is to provide improved control of the production of continuously cast elfervescing steel.
  • FIGURE l is a section through a casting with blow holes that prevent satisfactory rolling
  • FIGURE 2 is a part-section through another such casting
  • FIGURE 3 is a part-section through a casting with blow holes that permit satisfactory rolling
  • FIGURES 4 and 5 illustrate the change in the blowhole formation produced in a casting by means of the invention
  • FIGURE 6 shows part of one continuous casting machine
  • FIGURE 7 illustrates one method of automatic control of the C x O product
  • FIGURES 8 and 9 are enlarged sections on the line VIII-VIII in FIGURE 7.
  • FIGURES 1 to 3 show blow holes obtained in castings of large section from three melts A, B and C intended to yield products containing 0.05% carbon and 0.30% manganese. Details of the three steels and the casting conditions (including the cross-sectional size of the mold and therefore of the casting) are given in the following table:
  • the C x O product of Steel A was too low with the result that there were blow holes of moderate elongation at or close to the surface of the solidiiied steel, as shown in FIGURE 1.
  • the C x O product of Steel B was too high with the result that there were even more blow holes remarkably elongated and extending right to the surface, as shown in FIGURE 2.
  • FIG- URE 3 the blow holes in Steel C were buried well below the surface and were not elongated. In this steel, therefore, the C x O product (0.0019) was correct for the casting conditions.
  • C x O for steel of nominal composition 0.11% carbon and 0.35% manganese is between 0.0040 to 0.0045.
  • the steel is deliberately over-deoxidized before being poured, with the result that the C x O product is reduced to less than the predetermined value and the blow holes would reach the surface of the casting, and then the C x O product is raised to the desired value at which the blow holes are formed at a suitable depth below the surface by adding an oxidant.
  • the oxidant may be a solid, eg., iron ore, which may be added as powder in a carrier gas blown against a stream of the molten metal or into themolten metal.
  • oxygen which may conveniently be commercial oxygen or may even be in the form of air
  • one or more jets of this at the metal This may be done as the metal enters the mold, 4bu-t it is preferred to direct the jet or jets at the metal leaving the ladle, so that in effect one has in a launder or tundish a small reservoir of properly treated metal which is poured through the nozzle into the mold.
  • the initial slight over-deoxidation may be effected by any convenient deoxidant or deoxidants.
  • the deoxidant most commonly used with etervescing steel, namely aluminum, may be used, it is undesirable as a general rule in the process of the invention because when it is used alumina tends to build up in the nozzle through which the steel is poured and may -actually clog it.
  • the preferred deoxidant used in the invention is silicon, conveniently in the form of ferro silicon.
  • steel tapped yfrom a basic are furnace at 3981" F. had the following composition: 0.10% carbon, 0.11% manganese and 0.0040% oxygen.
  • the desired C x O product was about 0.0042. 12 lbs. per ton of manganese in the form of 78% manganese -ferro-alloy was added .to the steel in the ladle.
  • the steel was then cast at 2912 F. into a mold 7 x 3 inches in cross-section, the average casting speed speed being 60 inches per minute.
  • the carbon content was 0.11%, the manganese content 0.36% and the oxygen content 0.033%.
  • FIGURE 4 The structure of the steel initially cast is shown in FIGURE 4, the C x O product being only 0.0036, i.e. ⁇ too low. After enough steel had been cast to obtain the specimen from which FIGURE 4 was made, oxygen was blown against the stream of steel leaving the ladle, the oxygen being blown at a rate or 8 cubic feet per minute. The C x O product of the steel rose to 0.0042 and the structure of the resultant slab became that shown in FIGURE 5.
  • the invention may be carried out in the apparatus shown diagrammatically in FIGURE 6.
  • mol-ten steel is brought to the casting machine from a furnace in a ladle 1 having a pouring lip 2 from which a stream of metal runs as shown at 3.
  • the casting machine comprises a cross-launder 4 from which streams 5 flow to two tundishes 6 having nozzles 7 through which the molten metal iiows as streams 3 into open-ended Watercooled molds 9 to emerge as strands 10.
  • the steel in the ladle has been deoxidized, and oxygen is blown against the stream 3. As shown, oxygen is blown in this way through two pipes 11 which barnch from a single pipe 12 controlled by a valve 13.
  • Oxygen jets may, however, be directed not at the stream 3 but at the streams 5 leaving the launder, or at the streams 8 entering the mold, or onto the molten metal in the launder 4 or the tundishes 6.
  • the control may be made automatic. For instance use may be made of the fact that in the solidied metal below the mold there should be a rim substantially free from blow holes. Gamma rays will be intercepted by this rim to a greater extent than by metal containing blow holes. Accordingly, as shown in FIGURES 7 to 9, I may provide a source of gamma rays 16 and a detector 17 on opposite sides of the solidified metal 10 and so obtain a signal. This signal may be transmitted to an ins-trument 18 connected to control the setting of the valve 13.
  • the -source and detector are placed so that if the blow holes are adequately buried as shown in FIGURE 8 the instrument 1S does not respond, but if the blow holes approach the skin as shown in FIGURE 9 the amount of the rays passing through the billet will increase, and the resultant signal will cause increased opening of the valve 13.
  • the process ⁇ according to the present invention presents the advantage that if there should be any failure in the supply of oxidant the casting process wil-1 still continue safely.
  • a process for the continuous casting of etervescent steel to produce sound rimmed steel comprising (1) -over-deoxidizing molten steel and (2) reoxidizing said molten steel by directing at least one jet of oxygen on said molten steel and supplying yan amount of oxygen sutiicient to correct the overdeoxidized condition, and then (3) pouring said steel into a continuous casting mold .
  • said ⁇ steel effervesces and solidiies yforming a sound rimmed steel.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Continuous Casting (AREA)
US193243A 1961-05-09 1962-05-08 Production of effervescing steel Expired - Lifetime US3189956A (en)

Applications Claiming Priority (1)

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GB16908/61A GB952929A (en) 1961-05-09 1961-05-09 Improvements in the production of effervescing steel

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US3189956A true US3189956A (en) 1965-06-22

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GB (1) GB952929A (enrdf_load_stackoverflow)
NL (1) NL278244A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3623862A (en) * 1968-06-24 1971-11-30 Int Harvester Co Use of rare earth elements for reducing nozzle deposits in the continuous casting of steel process
US3875989A (en) * 1973-04-27 1975-04-08 Centre Rech Metallurgique Method of monitoring effervescence of a steel
US4055212A (en) * 1976-10-26 1977-10-25 Essex Group, Inc. Control system and method for controlling the oxygen content in continuously cast metal
US4484946A (en) * 1981-06-02 1984-11-27 Metal Research Corporation Method of producing iron-, nickle-, or cobalt-base alloy with low contents of oxygen, sulphur, and nitrogen
US4741772A (en) * 1984-05-08 1988-05-03 China Steel Corporation Si contained ferroalloy addition as a weak pre-deoxidation process in steelmaking

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU55257A1 (enrdf_load_stackoverflow) * 1968-01-12 1969-08-12

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1572179A (en) * 1922-06-05 1926-02-09 Jr Thomas J Bray Steel manufacture
US2181693A (en) * 1937-09-08 1939-11-28 Bethlehem Steel Corp Steel treatment
US2236504A (en) * 1938-07-28 1941-04-01 Bethlehem Steel Corp Manufacture of steel
GB695388A (en) * 1949-11-23 1953-08-12 Wieland Werke Aktien Ges Process for the continuous casting of iron and steel
US2928150A (en) * 1957-02-26 1960-03-15 Inland Steel Co Temperature control during metal casting
US2979394A (en) * 1957-11-14 1961-04-11 Niederrheinische Hutte Ag Method for preparing high grade rimmed steel with wide ferritic peripheral zone
US3127642A (en) * 1960-03-24 1964-04-07 Centre Nat Rech Metall Process and apparatus for the casting of steel

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1572179A (en) * 1922-06-05 1926-02-09 Jr Thomas J Bray Steel manufacture
US2181693A (en) * 1937-09-08 1939-11-28 Bethlehem Steel Corp Steel treatment
US2236504A (en) * 1938-07-28 1941-04-01 Bethlehem Steel Corp Manufacture of steel
GB695388A (en) * 1949-11-23 1953-08-12 Wieland Werke Aktien Ges Process for the continuous casting of iron and steel
US2928150A (en) * 1957-02-26 1960-03-15 Inland Steel Co Temperature control during metal casting
US2979394A (en) * 1957-11-14 1961-04-11 Niederrheinische Hutte Ag Method for preparing high grade rimmed steel with wide ferritic peripheral zone
US3127642A (en) * 1960-03-24 1964-04-07 Centre Nat Rech Metall Process and apparatus for the casting of steel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3623862A (en) * 1968-06-24 1971-11-30 Int Harvester Co Use of rare earth elements for reducing nozzle deposits in the continuous casting of steel process
DE1931694B2 (de) * 1968-06-24 1975-01-09 International Harvester Co., Chicago, Ill. (V.St.A.) Mischung zum Verhindern eines Verstopfens der Tauchausgußdüsen beim StahlstranggieBen
DE1931694C3 (de) * 1968-06-24 1975-09-11 International Harvester Co., Chicago, Ill. (V.St.A.) Mischung zum Verhindern eines Verstopfens der Tauchausgußdüsen beim Stahlstranggießen
US3875989A (en) * 1973-04-27 1975-04-08 Centre Rech Metallurgique Method of monitoring effervescence of a steel
US4055212A (en) * 1976-10-26 1977-10-25 Essex Group, Inc. Control system and method for controlling the oxygen content in continuously cast metal
US4484946A (en) * 1981-06-02 1984-11-27 Metal Research Corporation Method of producing iron-, nickle-, or cobalt-base alloy with low contents of oxygen, sulphur, and nitrogen
US4741772A (en) * 1984-05-08 1988-05-03 China Steel Corporation Si contained ferroalloy addition as a weak pre-deoxidation process in steelmaking

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GB952929A (en) 1964-03-18
NL278244A (enrdf_load_stackoverflow)

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