US3137566A - Method of pouring cast iron - Google Patents

Method of pouring cast iron Download PDF

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Publication number
US3137566A
US3137566A US128643A US12864361A US3137566A US 3137566 A US3137566 A US 3137566A US 128643 A US128643 A US 128643A US 12864361 A US12864361 A US 12864361A US 3137566 A US3137566 A US 3137566A
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Prior art keywords
cast iron
vacuum
melt
oxygen
ladle
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Expired - Lifetime
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US128643A
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English (en)
Inventor
Thieme Jochem
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Kolsch-Folzer Werke AG
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Kolsch-Folzer Werke 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
    • 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/08—Manufacture of cast-iron
    • 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/10—Making spheroidal graphite cast-iron

Definitions

  • the present invention relates to a method of and apparatus for casting cast iron. In connection with steel casting it is known to pass the liquid steel through a vaccum in order to obtain a degasification and a separation of harmful ingredients.
  • an empty casting ladle is inserted into a vacuum container which is tightly closed by a lid.
  • a second casting ladle is then tightly placed upon the ladle of the vacuum container.
  • the lid of the vacuum container has a passage for the liquid steel which passage is closed by a diaphragm. After the vacuum has been produced, the steel is poured in, whereby the diaphragm melts so that the steel will without loss in time enter the vacuum chamber.
  • FIG. 1 illustrates a diagrammatic section through an apparatus for carrying out the method according to the present invention.
  • FIG. 2 is a section through a modified apparatus according to the present invention.
  • the present invention is based on applicants finding that the reduction in the strength of the cast iron by vacuum treatment is caused by the reduction in the oxygen content of the melt.
  • the inventor was able to ascertain a reduction in the oxygen content from 40 to 70%.
  • the reduction in the strength of the cast iron depends on the separation of the carbon dissolved in the melt which carbon separates in the form of graphite during the solidification of the casting. Only if the carbon is separated in a certain form, the strength will be assured. This separation depends on the so-called nuclei. In connection with technical melting operations, only those foreign 3,137,566 Patented June 16, 1964 nuclei are of importance which consist to the major extent of silicates or oxides, i.e. of metallic or non-metallic compounds with oxygen. Such oxygen compounds can be present only if suflicient oxygen is present. If, however, not sufficient nuclei of this type are present, subcooling and other mis-formations of graphite crystals will occur which will at any rate produce a reduction in the strength.
  • the lack in nuclei is also a result of the loss in oxygen which is produced by the vacuum treatment of the melt because the melt due to the loss in oxygen loses its ability to form oxides.
  • the melt is again enriched with oxygen in order thus to produce a favorable nucleus condition. In this way, the reduction in strength will be safely avoided.
  • the cast iron melt was produced.
  • the charge may consist of pig iron, scrap, waste, and chips.
  • the liquid melt was poured into a plug ladle (Stopfenpfanne) and in this ladle was tightly placed upon a vacuum container. By opening the plug, the iron was discharged while melting an aluminum foil between the vacuum container and the plug ladle which aluminum foil had previously sealed the vacuum container. Thus, the iron passed into the vacuum chamber.
  • the melt passes through the vacuum chamber in a free flow and is collected in a casting ladle mounted below the vacuum chamber in a vacuum-tight container.
  • the cast iron will again be enriched with oxygen
  • a substance which gives off oxygen
  • Such substance may consist for instance of scale or the like.
  • oxygen may be introduced into the collecting ladle.
  • the melt will also give off hydrogen and nitrogen.
  • a reduction in the hardness will take place which, even after the enrichment with oxygen following the discharge from the vacuum, will be retained because the hardness is, in view of the gases, dependent on the carbide stabilizing effect and not on the oxygen content.
  • the hardness is reduced. This is favorable because the construction of machines favors a soft easily machinable cast iron with high strength.
  • a further advantage of the cast iron according to the present invention consists in that due to the reduction in hydrogen and nitrogen, the tendency to hard edges, bubbles and blow holes will be reduced.
  • the enrichment with oxygen after passing the melt through the vacuum may, of course, be omitted.
  • the invention may also be employed for making cast iron with spheroidal graphite.
  • Cast iron with spheroidal graphite is produced in a manner known per se by adding magnesium to the melted liquid iron.
  • the particular advantage of this known method consists in that the employed magnesium alloys are extremely inexpensive. For instance, when melting in acidic furnaces, of an alloy is employed which contains 15% magnesium and 85% nickel. A ton of such alloy costs approximately $2,500.00.
  • a portion of the sulphur present in the melt is removed while another portion binds the gases and more particularly oxygen and nitrogen.
  • a further portion of the magnesium will have to remain in the iron in solved condition.
  • the melt is passed through a vacuum prior to the magnesium treatment.
  • the oxygen and nitrogen will be removed from the melt and also a certain de-sulphurization (approximately 10%) will be obtained.
  • the inventors have ascertained that due to the vacuum treatment of the melt, approximately up to 40% of the magnesium alloy will be saved because the removal of oxygen and nitrogen and also of a portion of the de-sulphurization when passing the melt through the vacuum is already obtained and therefore no magnesium is required any longer.
  • the decrease in costs which is obtained by the treatment of the melt in conformity with the present invention is very considerable.
  • the vacuum treatment of the cast iron with ball or spheroidal graphite has a number of other advantages.
  • the heat conductivity of the iron increases by the vacuum treatment up to Due to the fact that the graphite stabilized gases hydrogen and nitrogen are removed already prior to the magnesium treatment, the cast iron with ball graphite in casting condition has a considerably greater toughness and considerably better strength properties which otherwise could be obtained only by tempering.
  • the expansibility in cast condition increases up to 75% and the bendability up to 200%. It has been found that the bending product (product of bending strength and bending) at 80 to 100% spherolite formation increases by from 200 to 500%.
  • Cast iron with ball graphite treated in conformity with the present invention does not produce any cementite, and the perlite component is reduced in favor of the ferrite component. According to the ordinary method, however, cementite is produced, and the perlite com ponent is high.
  • FIG. 1 the apparatus illustrated in FIG. 1 has a vacuum container 1 provided with a lid 2 at its upper end. Lid 2 and vacuum container 1 are by means of flanges 3 and an interposed seal 25 connected in an air-tight manner, for instance by bolts not shown in the drawing.
  • Lid 2 has an opening 4 with an outwardly extending connection 5 for connection with a vacuum pump 26 by means of which a vacuum may be produced and main tained in the vacuum container 1.
  • lid 2 is provided with a second seal 6 substantially centrally located in lid 2. Extending through this seal in an air-tight manner is a discharge connection 7 of a plug ladle 8.
  • the discharge connection 7 is by means of a flange 9 fixedly connected to a connection 11 which is arranged below the bottom 10 of the plug ladle 8 and extends downwardly. Between the flanges 9 and discharge connection 7 there is clamped an aluminum foil 18 or a foil of another easily meltable material which closes the discharge passage 12 in an air-tight manner so that after the plug ladle has been placed upon lid 2 of the vacuum container 1, no air Will be able to enter the interior of the vacuum container.
  • the discharge opening 13 of the plug ladle 8 may be closed by means of a plug 14.
  • a gripper member 15 or the like.
  • a casting ladle 16 Arranged in the interior of the vacuum container 1 is a casting ladle 16. This ladle is so arranged that it rests in the vacuum container substantially vertically below the mouth of the discharge connection 7.
  • the arrangement of the casting ladle in the interior of the container 1 has the advantage that no separate seal Will be required for connecting the casting ladle to the container. It is, of course, also possible to connect the casting ladle in an air-tight manner by means of a seal to the bottom side of an opening in the bottom of container 1.
  • the arrangement with the apparatus according to FIG. 1 is such that when inserting the casting ladle into the vacuum container 1, a substance 17, as for instance scale, adapted to give off oxygen is introduced into the casting ladle.
  • the apparatus illustrated in FIG. 1 operates in the following manner:
  • the casting ladle is inserted into the vacuum container 1, and the substance 17 adapted to give olf oxygen is introduced into the casting ladle 16.
  • lid 2 is connected to container 1 by means of flange 3 and by interposing a seal or gasket 25.
  • the plug ladle 8 is first placed on lid 2 of the vacuum container 1 and then is filled with molten cast iron. However, it may also be filled at another station and then placed u on lid 2. At any rate, prior to filling the plug ladle 8, the discharge opening 13 in the bottom 16 of the plug ladle is closed by plug 14 by means of the gripper member 15.
  • the ladle After the ladle has been filled and placed upon the lid 2 of the vacuum container 1, first by means of the vacuum pump 26 the required vacuum is produced in container 1. Then plug 14 of plug ladle 8 is lifted by means of i the gripper member 15. The cast iron melt Will then free space of the vacuum container 1, the cast iron melt will be degasified by the influence of the vacuum. As soon as the said melt enters the casting ladle, oxygen will be given off by the substance 17 to the melt so that the melt will be enriched with oxygen. As a result thereof, the cast iron will, following its degasification, obtain a favorable nucleus condition and will thus retain its strength.
  • FIG. 2 the apparatus illustrated therein for carrying out the method according to the present invention corresponds to a great extent to the device according to FIG. 1. Similar parts have, therefore, been designated with the same reference numerals as in FIG. 1 but have been primed, so that a description of these parts would appear to be superfluous.
  • the apparatus according to FIG. 2 differs from that of FIG. 1 primarily in that no substance giving oif oxygen is introduced into the casting ladle 16. Instead, during or following the filling with the cast iron melt, oxygen or an oxygen containing gas is introduced into the melt which is in the casting ladle 16. To this end, the wall of the vacuum container 1' is connected to a source of oxygen not shown in the drawing. Into the interior of the vacuum container 1' there is introduced a gas conduit 20 which leads into the casting ladle 16 and has its mouth spaced from the upper level of themelt relatively slightly so that a goo-d intermixing effect of the entire cast iron melt in the interior of the ladle with oxygen will be assured. The oxygen may be blown through conduit 20 into the cast iron melt in the interior of the ladle 16. However, it is also possible to draw oxygen through the bath of the melt by means of a vacuum pump (not shown) connected to the connection 5'.
  • a vacuum pump not shown
  • the feeding of oxygen is effected following the filling of the casting ladle 16' with cast iron. However, it may also be effected already during the filling operation. In this connection, however, it should be borne in mind that in spite of the feeding of oxygen into the interior of the vacuum container, a sufiicientvacuum must be maintained. In other respects, the apparatus according to FIG. 2 operates in the same manner as that described above in connection with FIG. 1.
  • a method of making cast iron with spheroidal graphite which includes the steps of: passing the cast iron melt through a vacuum, and subsequently adding magnesium to said cast iron melt.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
US128643A 1960-08-13 1961-07-31 Method of pouring cast iron Expired - Lifetime US3137566A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3222161A (en) * 1963-06-10 1965-12-07 Duriron Co Vacuum treated high silicon cast iron and process for making same
US3271137A (en) * 1964-01-02 1966-09-06 Duriron Co Vacuum treated high silicon cast iron with graphitizing inoculant
US3390568A (en) * 1965-01-22 1968-07-02 Taylor Gilbert Apparatus for determining the carbon content of metals
US3472503A (en) * 1966-02-01 1969-10-14 Bbc Brown Boveri & Cie Vacuum degassing apparatus for molten metals
US3508914A (en) * 1965-10-07 1970-04-28 Us Navy Methods of forming and purifying nickel-titanium containing alloys
US4049248A (en) * 1971-07-16 1977-09-20 A/S Ardal Og Sunndal Verk Dynamic vacuum treatment
EP0104392A1 (de) * 1982-08-26 1984-04-04 Franco Zanardi Verfahren zur Herstellung von Kugelgraphitgusseisen und Vorrichtung zur Durchführung des Verfahrens

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2182064A (en) * 1935-10-31 1939-12-05 Wacker Chemie Gmbh Apparatus for treating matters in hot liquid state
US2253421A (en) * 1938-09-20 1941-08-19 Mare Baltzar E L De Method and apparatus for deoxidizing and degasifying liquid steel
US2587793A (en) * 1949-04-05 1952-03-04 Waldron Frederic Barnes Manufacture of steel
US2734240A (en) * 1956-02-14 Vacuum pouring apparatus
FR1196042A (fr) * 1956-12-24 1959-11-20 Hoerder Huettenunion Ag Procédé de désulfuration des coulées de fonte brute, notamment des coulées de fonte de moulage
GB852424A (en) * 1956-12-24 1960-10-26 Hoerder Huettenunion Ag Improvements relating to methods of desulphurising pig iron and cast iron melts
US2993780A (en) * 1957-11-16 1961-07-25 Siderurgie Fse Inst Rech Method for treating steel in vacuo

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734240A (en) * 1956-02-14 Vacuum pouring apparatus
US2182064A (en) * 1935-10-31 1939-12-05 Wacker Chemie Gmbh Apparatus for treating matters in hot liquid state
US2253421A (en) * 1938-09-20 1941-08-19 Mare Baltzar E L De Method and apparatus for deoxidizing and degasifying liquid steel
US2587793A (en) * 1949-04-05 1952-03-04 Waldron Frederic Barnes Manufacture of steel
FR1196042A (fr) * 1956-12-24 1959-11-20 Hoerder Huettenunion Ag Procédé de désulfuration des coulées de fonte brute, notamment des coulées de fonte de moulage
GB852424A (en) * 1956-12-24 1960-10-26 Hoerder Huettenunion Ag Improvements relating to methods of desulphurising pig iron and cast iron melts
US2993780A (en) * 1957-11-16 1961-07-25 Siderurgie Fse Inst Rech Method for treating steel in vacuo

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3222161A (en) * 1963-06-10 1965-12-07 Duriron Co Vacuum treated high silicon cast iron and process for making same
US3271137A (en) * 1964-01-02 1966-09-06 Duriron Co Vacuum treated high silicon cast iron with graphitizing inoculant
US3390568A (en) * 1965-01-22 1968-07-02 Taylor Gilbert Apparatus for determining the carbon content of metals
US3508914A (en) * 1965-10-07 1970-04-28 Us Navy Methods of forming and purifying nickel-titanium containing alloys
US3472503A (en) * 1966-02-01 1969-10-14 Bbc Brown Boveri & Cie Vacuum degassing apparatus for molten metals
US4049248A (en) * 1971-07-16 1977-09-20 A/S Ardal Og Sunndal Verk Dynamic vacuum treatment
EP0104392A1 (de) * 1982-08-26 1984-04-04 Franco Zanardi Verfahren zur Herstellung von Kugelgraphitgusseisen und Vorrichtung zur Durchführung des Verfahrens

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