EP0137618B1 - Procédé et appareil pour introduire du calcium dans un bain de fer fondu - Google Patents

Procédé et appareil pour introduire du calcium dans un bain de fer fondu Download PDF

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Publication number
EP0137618B1
EP0137618B1 EP84305326A EP84305326A EP0137618B1 EP 0137618 B1 EP0137618 B1 EP 0137618B1 EP 84305326 A EP84305326 A EP 84305326A EP 84305326 A EP84305326 A EP 84305326A EP 0137618 B1 EP0137618 B1 EP 0137618B1
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EP
European Patent Office
Prior art keywords
wire
lance
calcium
bath
molten
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84305326A
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German (de)
English (en)
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EP0137618A3 (en
EP0137618A2 (fr
Inventor
Joseph Gerard Kaiser
Emil Joseph Wirth
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.)
Cessione minerals Technologies Inc
Original Assignee
Pfizer Inc
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Filing date
Publication date
Priority claimed from US06/522,754 external-priority patent/US4481032A/en
Priority claimed from US06/522,753 external-priority patent/US4512800A/en
Application filed by Pfizer Inc filed Critical Pfizer Inc
Priority to AT84305326T priority Critical patent/ATE35290T1/de
Publication of EP0137618A2 publication Critical patent/EP0137618A2/fr
Publication of EP0137618A3 publication Critical patent/EP0137618A3/en
Application granted granted Critical
Publication of EP0137618B1 publication Critical patent/EP0137618B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • C21C1/02—Dephosphorising or desulfurising
    • 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
    • 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
    • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
    • 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
    • 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
    • C21C7/064—Dephosphorising; Desulfurising
    • 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
    • C21C7/068—Decarburising

Definitions

  • This invention relates to the field of processing of molten metals, in particular to a process and an apparatus for adding refining or alloying ingredients to improve properties of a metal being processed.
  • a ferrous melt is typically produced in a suitable furnace and then tapped into a ladle where it is treated with one or more ingredients for refining or alloying purposes.
  • the low density (relative to steel), volatility and reactivity of calcium severely complicate the task of providing a satisfactory process for its addition to the molten material in the ladle.
  • molten metal In metal processing, and in particular steel processing, molten metal generally is separated from a quantity of slag which remains relatively solid and floats upon the surface of the molten metal.
  • the slag is made up of various lower- density impurities, quantities of oxidized metals and the like.
  • the additive In order to feed an additive material into the molten metal, the additive must be placed below or caused to pass through the slag surface.
  • additive materials intended to improve the properties of e.g., steel are typically relatively expensive and must be conserved. Any waste of a calcium-containing additive material, for example by the loss of material in the slag layer during addition, can have a major economic impact on the producer and the product. It is therefore highly desirable to feed the calcium well below the surface of the molten metal to the point where it will be most effective, and to mix the molten metal to evenly distribute the calcium additive therein.
  • calcium has also been added to melts in steelmaking ladles in the form of a calcium metal-containing wire (clad or unclad) continuously fed through the upper surface of the melt.
  • wire feeding is that large flows of gas are not needed, as in powder injection, to propel the calcium-containing material into the molten ferrous material.
  • the high volatility of calcium hinders the attainment of an efficient utilization of the calcium added in surface wire feeding. If the wire does not penetrate to a sufficient depth below the surface before the calcium in the wire desolidifies, a low residence time and poor utilization of the calcium results along with a non-uniform treatment of the melt.
  • U.S. Patent 4,154,604 discloses a method and apparatus for adding a wire to molten metal in a vessel through a refractory clad tube filled with pressurized inert gas.
  • This patent does not, however, disclose the desirability of effecting the melting of wire constituents at a substantial dis- tancefrom the lowertip of the refractory clad tube in or directly below a region of downwelling of the molten metal. In fact, such a result is physically precluded in the preferred embodiment disclosed in said patent by the close proximity of the lower tip of the tube to the bottom wall of the vessel.
  • a novel process for adding calcium to a bath of molten ferrous material comprises feeding a calcium metal-containing wire having a lower density than said ferrous material downwardly through a refractory lance inserted into said bath while providing a sufficient flow of inert gas through said lance to maintain the interior of the lance essentially free of said molten ferrous material and to induce substantial recirculatory stirring of said molten material, with the disposition of the lance in said bath and the composition, cross-sectional dimensions and feeding rate of said wire being such that (a) said wire bends substantially towards the horizontal direction after exiting from the wire outlet of the lance and before fully decomposing, and (b) at least a major part of the desolidification of the calcium in said wire occurs by melting in or directly below a region of downwelling of said molten ferrous material at a depth below the surface of said bath at which the ferrostatic pressure is greaterthan the vapor pressure of calcium at the temperature of said molten ferrous material.
  • the buoyancy of the wire resulting from its lower density than that of the melt, that causes itto bend.
  • the wire outlet of the lance is positioned at a depth below the surface of said bath at which the ferrostatic pressure is greater than the vapor pressure of calcium at the melt temperature.
  • This countercurrent flow of the rising calcium and circulating molten ferrous phases greatly enhances the degree of contact between the calcium and the molten ferrous material and further increases the calcium residence time in the bath. As a result, the efficiency of utilization of the calcium refining additive is substantially improved.
  • Another advantage of the process of the present invention is that the inert gas flow rate in the lance can be varied independently of the wire feeding rate to optimize the internal melt circulatory stirring rate and the extent of slag/metal contact at the surface of the bath.
  • the present invention also includes a novel apparatus for efficiently adding a processing element in the form of a wire directly into a quantity of molten material, said apparatus comprising a heat-resistant nozzle having an outlet disposable beneath the surface of the molten material, means for feeding the wire into the nozzle, and means for concurrently injecting an inert gaseous medium into the nozzle together with the wire, thereby preventing closure of the nozzle by solidification of molten material therein while agitating the molten material by gas bubble agitation.
  • a seal device having opposed, pressure- biased pistons engages the wire upstream (relative to wire feed) of the source of inert gas, which gas is fed together with the wire through a gas-tight conduit to the nozzle.
  • a particular configuration of the bore of the nozzle maximizes the effect of the inert gas.
  • a restriction in the flow path adjacent the outlet of the nozzle creates an area of increased gas velocity, whereby any irregularities which may occur in the feeding of wire do not give rise to the passage of molten metal into the interior of the nozzle.
  • the novel apparatus of the invention is inexpensive, convenient in use, effective in starting, stopping and during use, and requires use of the least amount of additive necessary to achieve a given concentration in the processed metal.
  • a suitable apparatus for use in.feeding a calcium metal-containing wire 1 into a bath 2 of molten ferrous material, e.g., steel, contained in a ladle 3 (which is open to the atmosphere) is schematically depicted in Figures 1 and 2.
  • wire 1 has a lower density than the molten ferrous material 2.
  • the term "calcium metal-containing wire” means that such a wire is comprised at least in part of unalloyed elemental metallic calcium as a distinct phase.
  • the wire may also contain distinct phases of calcium alloys (e.g. a calcium-aluminum alloy) or calcium compounds (e.g.
  • the calcium metal-containing wire may be clad (e.g. with a steel cladding) or unclad.
  • the calcium metal-containing core of the clad wire may itself be a wire or may exist in any other known form, e.g. a powder.
  • a surface layer4 of a basic synthetic slag containing e.g. lime and fluorspar is applied to the melt 2 prior to commencement of the wire feeding.
  • wire 1 is fed into melt 2 downwardly through a refractory lance 5 inserted into the bath 2 of molten ferrous material.
  • a flow of gas inert to the molten ferrous material e.g. argon
  • This inert gas exits from the wire outlet 6 of lance 5 and rises as a multiplicity of bubbles 7 surrounding lance 5 to the surface of the melt.
  • the pressure and flow rate of the inert gas must be sufficient to maintain the inner bore of the lance free of molten ferrous material and thus prevent blockage of the bore by solidification of said material.
  • the inert gas pressure and flow rate should be sufficient to induce a substantial recirculatory stirring of the melt 2 in ladle 3 (note arrows in bath 2 in Figure 1).
  • the inert gas flow rate is not so high as to generate a large amount of turbulence on the surface of the melt as the bubbles 7 escape to the atmosphere.
  • a preferred range for the flow rate of inert gas through lance 5 is from about 1.56-4.16x10- e m3fs. kg (1.5x10- 5 to about 4x10- 5 standard ft 3 / (min - Ib of melt)).
  • the inert gas in lance 5 Since the inert gas in lance 5 is not relied upon to propel the wire 1 into the melt, its flow rate through the lance can be adjusted independently of the wire feeding rate.
  • the inert gas pressure in lance 5 must, of course, be greater than the ferrostatic pressure at the wire outlet.
  • refractory lance means that at least those outermost longitudinal portions of lance 5 that come into contact with the molten ferrous material 2 are made of a refractory material (e.g. alumina) that is resistant to physical or chemical change while subjected to such contact.
  • lance 5 is straight and oriented in a vertical manner while wire 1 is being fed through it.
  • lance 5 may also be tilted away from a vertical orientation during the wire feeding (but not horizontal).
  • the lance may have a "dog-legged" shape.
  • the lance is provided with a wire inlet and a wire outlet, with the wire inlet at a higher elevation during use than the wire outlet.
  • the wire outlet is at the lower tip of the lance.
  • the apparatus shown in Figure 1 includes a wire spool 8, a mechanical wire feeder 9, an inert gas feeding and sealing assembly 10 and a gas-tight wire conduit 11 connecting assembly 10 to and supporting lance 5.
  • a mechanical wire feeder, an inert gas feeding and sealing assembly and a refractory lance of the types disclosed in Figures 4 to 11 herein.
  • wire 1 includes exposed elemental calcium metal at its outer surface, such as when it is an unclad calcium metal wire, conventional steps will have to be taken to protect the wire on spool 8 from atmospheric attack, such as maintaining spool 8 in a housing pressurized with calcium-inert gas.
  • the temperature of the molten ferrous material 2 in ladle 3 ranges from 1538-1649°C (about 2800°F to about 3000°F). At these temperatures the vapor pressure of calcium is quite substantial. As discussed earlier, it is essential to the full success of the calcium addition operation that a major part (or all) of the desolidification of the elemental calcium metal in wire 1 occur by melting rather than by vaporization. Thus, this desolidification must occur below the critical depth in the melt, which is defined as that depth below the surface of the melt at which the ferrostatic pressure is equal to the vapor pressure of calcium (at the melt temperature). The critical depth may be readily determined as a function of temperature by using the chart provided in Figure 3.
  • the rightmost curve in Figure 3 is a plot of calcium vapor pressure vs. temperature, while the leftmost curve is a plot of ferrostatic pressure vs. depth below the surface of the melt.
  • the vapor pressure of calcium is 1.57 atm.
  • a ferrostatic pressure of 1.59x10 5 Pascal (1.57 atm.) is experienced at a depth of 0,85 m (2.8 feet), which is thus the critical depth at 1571°C (2860°F).
  • wire 1 is an unclad calcium metal wire having a diameter of from about 8 mm to about 12 mm
  • lance 5 is straight and vertically-oriented in the bath
  • the wire outlet 6 of lance 5 is at the lower tip of the lance and is positioned below the critical depth D
  • the distance between the longitudinal axis of the lance and the inner surface of the nearest ladle side wall is from about 1/6 to about 1/3 of the longest linear dimension of the bath (in horizontal planes)
  • the temperature of the molten ferrous material 2 is from 1538-1649°C (about 2800°F to about 3000°F)
  • a preferred range for the wire feeding rate in the practice of the present invention is from 2.54-5.08 m/s (about 500 ft/min to about 1000 ft/min).
  • a 2.44 m (8 ft) long straight refractory lance of the type described in Figures 5-7 was then disposed in the bath of molten steel, with the lance being vertically-oriented and positioned on the major axis of the elliptical ladle cross-section at a distance of about 1/3 of the length of said major axis from the inner surface of the nearest ladle side wall, and with its wire outlet at its lower tip being positioned 1.83 m (6 ft) below the surface of the molten steel bath.
  • the wire After exiting from the lower tip of the lance, the wire bent substantially towards the horizontal direction. Complete decomposition of the wire occurred at a distance of about 3.05 m (10 feet) from the lower tip of the lance.
  • the molten steel in the ladle was tapped and cast into appropriate molds.
  • the cast steel product contained 0.22 wt.% carbon, 1.36 wt.% manganese, 0.03 wt.% aluminum, 0.12 wt.% vanadium, 0.005 wt.% sulfur and 45 ppm calcium. 100% inclusion modification was observed.
  • Example 1 The procedure of Example 1 may be repeated with the use of an unclad calcium metal wire. Operating equipment and conditions are substantially unchanged, except that an unclad 12 mm diameter calcium metal wire is fed to the bath of molten steel for one minute at a rate of 4.06 m/s (800 ft/min). After exiting from the wire outlet at the lower tip of the lance, the wire bends substantially towards the horizontal direction. Complete decomposition of the wire occurs at a distance of about 3.05 m (10 feet) from the lower tip of the lance.
  • FIG. 4 A preferred embodiment of the apparatus of the invention is illustrated in Figures 4 to 11.
  • One or more processing elements for treating a molten metal product are disposed in, or otherwise form a part of, a wire 20.
  • Such elements are hereinafter sometimes referred to as being in wire-form.
  • the general objective is to convey the wire 20 from reel 22 to the quantity of molten metal 56 in receptacle 52.
  • a feeding mechanism 24 draws the wire from the reel and advances the wire along a feed path.
  • Inert gas is supplied to the gas-tight conduit, and a seal mechanism 30 located immediately upstream of the inert gas input prevents loss of inert gas around wire 20 in a direction backwards along the feed path.
  • the nozzle 60 of the invention shown in detail in Figures 5 to 7, comprises a refractory ceramic casing 62, through which the calcium wire is conveyed in metallic conduit portions 66 and 70 to the ultimate outlet or discharge point 84.
  • Refractory casing 62 may be made of alumina (A1 2 0 3 ) or any other suitable refractory material such as those used to line kilns and the like.
  • the overall nozzle is made long enough to extend to a preselected depth in the reservoir of molten metal. It is usually preferred that the wire additive be discharged from the nozzle at least 0.91-1.52 m (3 to 5 feet) below the slag/metal interface. Accordingly, with, due regard to the high temperature and corrosive nature of the slag and metal, the refractory casing 62 should be on the order of 3.05 m (10 feet) long.
  • the nozzle 60 may be raised and lowered with respect to the metal receptacle 52, or vice versa, by means of appropriate mechanical linkages.
  • the metal receptacle 52 may be carried by a winch/conveying system, including yoke assembly 48.
  • it may be preferable to raise and lower the entire feed mechanism as a unit, as shown in Figure 11. In any event, it is beneficial to avoid flexing the conduit 44.
  • the central wire-carrying portion of nozzle 60 includes a metallic conduit 66 leading to metallic conduit 70, through both of which the wire 20 is passed.
  • the larger conduit 66 carries the wire to near the discharge opening 84 of nozzle 60.
  • An enlarged bore 68 is formed at the end of large conduit 66, into which bore small conduit 70 is placed.
  • Small conduit 70 and large conduit 66 are joined by threads, or by weld 72, or by other convenient means.
  • the discharge end of the smaller conduit 70 at the extreme end of nozzle 60, has an elongated, gradually tapered funnel-shaped section 80 of decreasing internal diameter in the direction of flow.
  • the narrower end 82 of the funnel-shaped section there is an abrupt increase in diameter, formed by a relatively short substantially cylindrical section 83 of substantially uniform diameter.
  • this particular variation in diameter along the direction of wire travel has certain advantages.
  • the cross-section is adapted to cooperatively prevent the molten metal 56 from running upwards into the nozzle.
  • encroaching molten metal may solidify in the nozzle along the internal areas of conduits 66 and 70 and there bind the wire to the conduit.
  • the inert gas passing outwards through the nozzle together with wire 20 agitates the metal 56, mixing the additive and the molten metal, thus providing for a more even distribution of the additive material.
  • the inert gas also functions to keep the nozzle cool.
  • the wire-form additive In order to add the wire-form additive to the molten metal 56 at a point well below the surface of molten metal, it is necessary to overcome substantial fluid pressure in the molten metal.
  • the fluid pressure is, of course, a function of the depth below the surface of molten metal. The particular pressure will depend upon the particular metal, but will usually be quite substantial at a depth of one or two meters.
  • the pressure of inert gas supplied must overcome this fluid pressure in order to prevent molten metal 56 from rising in the nozzle. Should any molten metal be permitted to run into the nozzle, wire 20 can immediately be seized and welded to a conduit wall as the molten metal solidifies.
  • the additive material in the form of wire 20 melts after discharge into the reservoir of molten metal 56. Bubbles 88 of inert gas rise toward the surface of molten metal 56, agitating the molten metal and causing an overall flow therein, upwards adjacent the nozzle and downwards at other areas, namely around the periphery of the molten metal reservoir 52.
  • conduit 70 The decreasing internal diameter of conduit 70 is intended to maximize the gas velocity immediately adjacent the ultimate outlet 84 of the nozzle.
  • the gas at constant pressure, increases in velocity up to the restriction 82.
  • an open cavity or chamber formed by the uniformly cylindrical section 83 of the bore serves to space the restriction 82 from the molten metal 56, further guarding against the entry of molten metal into the restricted orifice 82.
  • the wire is maintained well clear of the lowermost edges of the conduit 70 which are unavoidably exposed to the molten metal, and cannot be welded to these edges by solidifying metal cooled by contact with the nozzle.
  • the wire 20 As the wire 20 is fed, it can be expected to vibrate and rattle around the allowed space in restricted orifice 82.
  • the wire remains centrally positioned in the discharge opening 84 even if resting against an edge of the restricted orifice wall.
  • the space which is left open between the wire and the wall of restricted orifice 82 is small enough that the gas pressure overcomes the fluid pressure of displaced molten metal, othewise tending to flow up the nozzle. Interactive movement of the wire and the inert gas enhance the ability of the nozzle to resist clogging.
  • seal mechanism 30 is provided to prevent a backwash of inert gas.
  • Seal mechanism 30 comprises a housing having at least one pair of opposed pistons 32 having contoured sealing surfaces for slidably engaging the wire moving therebetween, which clasp the advancing additive wire 20 in a gas-tight fashion. Downstream of the opposed pistons 32, the inert gas is fed from inert gas source 31 via conduit 33 to the area of wire 20, the wire now being enclosed in a gas-tight conduit 44 leading from seal 30 to the nozzle 60.
  • a compressed air source 34 is preferably used to drive opposed pistons 32 against wire 20. Spring biasing, hydraulic pressure or the like are also possible.
  • a manifold 36 may be used to equally distribute the air pressure of compressor 34 or other source.
  • Opposed pistons 32 are slidably mounted in gas-tight cylinders, and sealed therein by means of resilient "O"-rings, for example two per piston.
  • the equalization of gas pressure by means of manifold 36 results in equal pressure on opposed pairs of axially aligned pistons 32, at each stage thereof. Two stages or pairs of opposed pistons are shown, disposed in parallel relationship. It will be appreciated that the opposed pistons may likewise be mounted at right angles, or as otherwise desired.
  • the pairs may also be operated independently such that one pair provides an atmosphere seal and the other pair provides an inert gaseous medium seal.
  • the housing of seal unit 30 is preferably made of steel.
  • the pistons 32, mounted in the cylinders of the housing, are made of a durable plastic material.
  • the pistons may, for example, be made from or coated with teflon@, nylon@, or the like.
  • the housing of seal 30 is provided with an enlarged, funnel-shaped input orifice 35, adapted to "capture” the advancing end of wire 20. It may be necessary to additionally spring-bias opposed pistons 32, or provide for a manual adjustment, in order to ensure their central alignment during the initial loading of wire 20. Once loaded, however, the seal mechanism 30 will compensate for variation in the transverse position of wire 20 with respect to the seal 30, while maintaining the gas-tight seal thereof. Inasmuch as the sheathed wire is quite stiff, it is necessary to allow some variation in alignment in order to prevent undue friction and to maintain the seal.
  • a suitable control mechanism may be connected simultaneously to the pinch roller wire feed device 24 and to the inert gas pressure control 42.
  • the gas control 42 should be left closed until the wire becomes engaged by opposed pistons 32 of seal 30.
  • no particular gas pressure is required until the injector nozzle 60 is brought into proximity with the molten metal 56, or the slag 54 thereupon.
  • the feeder and inert gas pressure control may be simultaneously activated, and the nozzle plunged into the molten metal. Melting additive and inert gas are discharged at the nozzle orifice, well below the slag/ metal interface.
  • FIG. 11 A preferred physical arrangement of the system is shown in Figure 11. Virtually the entire system is disposed upon a pivotally-mounted table 120, which pivots on hinge 122. A hydraulic or pneumatic lifting device 124 is operable to lift and lower the table 120 about its pivot, thereby raising and lowering nozzle 60 with respect to the molten metal 56 in container 52. The lifting mechanism may likewise be incorporated under the common inert gas/wire feed control.
  • the nozzle 60 is formed with a bore having, with respect to the direction of additive feed and inert gas flow, a substantially cylindrical section of substantially uniform diameter, followed by a tapered section of decreasing diameter terminating at an aperture having a radius only slightly larger than that of the wire and a second substantially cylindrical section of substantially uniform diameter larger than that of said aperture, whereby the wire remains spaced from the internal edges of the nozzle conduit adjacent the outlet.
  • An abrupt transition between the tapered and second cylindrical sections creates a restricted diameter orifice with increased gas velocity therein, past which orifice the molten metal does not backflow.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Claims (10)

1. Procédé pour additionner du calcium à un bain (2) de matière ferreuse en fusion, qui conste à faire descendre dans une lance réfractaire (5) introduite dans le bain (2) un fil (1) contenant du calcium métallique ayant une densité inférieure à celle de ladite matière ferreuse, ladite lance (5) contenant un gaz inerte entourant ledit fil (1) sous une pression suffisante pour maintenir la lance (5) essentiellement exempte de ladite matière ferreuse en fusion, au moins une partie majeure de la désolidification du calcium dans ledit fil (1) ayant lieu à une profondeur, au-dessous de la surface dudit bain (2), à laquelle la pression ferrostatique est supérieure à la pression de vapeur du calcium à la température de ladite matière ferreuse en fusion, caractérisé en ce qu'un écoulement suffisant dudit gaz inerte est produit dans ladite lance (5) pour induire une agitation à recirculation importante de ladite matière en fusion, et la disposition de la lance (5) dans ledit bain (2) et la composition, les dimensions de la section transversale et la vitesse d'avance dudit fil (1) sont telles que (a) ledit fil (1)
se courbe sensiblement vers la direction horizontale après avoir débouché de la sortie (6) de fil de ladite lance (5) et avant d'être complètement décomposé, et (b) au moins une partie majeure de la désolidification du calcium dans ledit fil (1) a lieu par fusion dans une zone de plongée de ladite matière ferreuse en fusion ou directement au-dessous de cette zone.
2. Procédé selon la revendication 1, dans lequel la sortie (6) du fil de ladite lance (5) est positionnée, alors que ledit fil (1) est avancé dans ladite lance (5), à une profondeur, au-dessous de la surface dudit bain (2), à laquelle la pression ferrostatique est supérieure à la pression de vapeur du calcium à la température de ladite matière ferreuse en fusion.
3. Procédé selon la revendication 2, dans lequel ladite lance (5) est droite, ladite sortie (6) du fil est au bout inférieur de la lance (5), ladite lance (5) est orientée verticalement, tandis que ledit fil (1) est avancé dans elle, et ladite lance (5) est disposée de façon excentrée dans ledit bain (2), comme vu dans des plans horizontaux, tandis que ledit fil (1) est avancé dans ladite lance (5).
4. Procédé selon la revendication 3, dans lequel ledit bain (2) est maintenu dans un récipient (3) comportant un fond et des parois latérales globalement verticales et la distance entre l'axe longitudinal de ladite lance (5) et la surface intérieure (12) de la paroi latérale du récipient qui en est la plus proche est d'environ 1/6 à environ 1/3 fois la dimension linéaire la plus longue (L) dudit bain (2) dans des plans horizontaux de coupe transversale.
5. Appareil pour injecter un élément de traitement sous la forme d'un fil (20) au-dessous de la surface d'une matière en fusion, comprenant:
une tuyère (60) résistant à la chaleur, pouvant être amenée dans une position de travail dans laquelle une entrée est disposée au-dessus de ladite surface et une sortie (84) est disposée au-dessous de ladite surface, ladite tuyère (60) présentant un alésage ayant un tronçon (80) en forme d'entonnoir aboutissant à une ouverture (82) ayant un rayon qui n'est que légérement supérieur à celui dudit fil (20), et un tronçon sensiblement cylindrique (83) d'un diamètre sensiblement uniforme, dans lequel ladite ouverture (82) débouche, le diamètre dudit tronçon (83) de diamètre uniforme étant assez supérieur au diamètre de ladite ouverture (82) pour former une brusque transition entre lesdits deux tronçons (80, 83), l'ouverture située à l'extrémité dudit tronçon (83) de diamètre sensiblement uniforme étant opposée à ladite ouverture (82) formant la sortie (84) de la tuyère;
un conduit (44) étanche aux gaz raccordé par une extrémité à l'entrée de la tuyère;
des moyens (30) disposés à l'autre extrémité du conduit (44) et destinés à recevoir de façon étanche le fil (20);
des moyens (31, 33, 42) destinés à injecter un gaz inerte dans le conduit (44); et
des moyens (24) destinés à faire avancer le fil (20) dans et à travers le conduit (44) et la tuyère (60) et à l'introduire directement à l'intérieur de la matière en fusion.
6. Appareil selon la revendication 5, dans lequel lesdits moyens (30) destinés à recevoir de manière étanche le fil (20) comprennent au moins une paire de pistons (32) actionnés par pression disposés coaxialement et pouvant être rapprochés l'un de l'autre, les pistons (32) présentant des surfaces profilées d'étanchéité destinées à établir un contact de glissement avec le fil (20) se déplaçant entre eux; et dans lequel lesdits moyens destinés à injecter un gaz inerte dans le conduit (44) comprennent une source (31) de gaz inerte sous pression et des moyens (33, 42) destinés à raccorder ladite source (31) aux moyens (30) pour recevoir de façon étanche le fil (20), en aval de la ou des paires de pistons (32) et en amont du conduit (44).
7. Appareil selon la revendication 6, dans lequel lesdits moyens (30) destinés à recevoir de façon étanche le fil (20) comprennent en outre un collecteur de gaz (36) destiné à commander les pistons (32) sous une pression égale et une source (34) de gaz comprimé pour le collecteur (36).
8. Appareil selon la revendication 6, dans lequel lesdits moyens (30) destinés à recevoir de façon étanche le fil (20) comprennent deux paires de pistons (32) séparées l'une de l'autre dans la direction d'avance du fil, l'une desdites paires formant un joint d'étanchéité à l'atmosphère et l'autre formant un joint d'étanchéité auxgaz inertes.
9. Tuyère (60) pour injecter un élément de traitement sous la forme d'un fil (20) directement à l'intérieur d'une matière en fusion et analogue, comprenant un corps allongé (62) formé d'une matière hautement résistante à la température et traversé d'un alésage axial par l'intermédiaire duquel le fil (20) peut être avancé directement dans la matière en fusion, ledit alésage aboutissant à une ouverture (84) par laquelle le fil (20) sort de la tuyère (60), caractérisée en ce que ledit alésage est caractérisé par un resserrement de diamètre (82) en amont de l'ouverture (84) d'aboutissement, un tronçon (80) en forme d'entonnoir en amont dudit resserrement (82) et une transition brusque dudit tronçon (80) en forme d'entonnoir à un tronçon (83) de diamètre sensiblement uniforme, en aval dudit resserrement (82) et adjacent à l'ouverture (84) d'aboutissement, ledit tronçon (80) en forme d'entonnoir étant axialement relativement plus long que ledit tronçon (83) de diamètre uniforme.
EP84305326A 1983-08-12 1984-08-06 Procédé et appareil pour introduire du calcium dans un bain de fer fondu Expired EP0137618B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84305326T ATE35290T1 (de) 1983-08-12 1984-08-06 Verfahren und vorrichtung zum einbringen von calcium in eisenschmelzen.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US06/522,754 US4481032A (en) 1983-08-12 1983-08-12 Process for adding calcium to a bath of molten ferrous material
US06/522,753 US4512800A (en) 1983-08-12 1983-08-12 Wire injection apparatus
US522754 1983-08-12
US522753 1983-08-12

Publications (3)

Publication Number Publication Date
EP0137618A2 EP0137618A2 (fr) 1985-04-17
EP0137618A3 EP0137618A3 (en) 1986-04-02
EP0137618B1 true EP0137618B1 (fr) 1988-06-22

Family

ID=27060927

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84305326A Expired EP0137618B1 (fr) 1983-08-12 1984-08-06 Procédé et appareil pour introduire du calcium dans un bain de fer fondu

Country Status (8)

Country Link
EP (1) EP0137618B1 (fr)
JP (1) JPH0347909A (fr)
KR (1) KR880000468B1 (fr)
AU (1) AU550957B2 (fr)
BR (1) BR8404033A (fr)
DE (1) DE3472274D1 (fr)
DK (1) DK386284A (fr)
ES (3) ES8700330A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0273576A1 (fr) * 1986-11-28 1988-07-06 Pfizer Inc. Tuyère pour l'introduction d'un fil de traitement
FR2764905A1 (fr) * 1997-06-23 1998-12-24 Pechiney Electrometallurgie Procede de traitement du plomb fondu par le calcium et fil a base de calcium pour ce traitement

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE456001B (sv) * 1983-11-08 1988-08-29 Bind O Matic Ab Block samt sett att framstella detsamma
WO1986004359A1 (fr) * 1985-01-24 1986-07-31 Vallourec Procede de traitement de metaux liquides par fil fourre contenant du calcium
RU2152834C1 (ru) * 1999-12-06 2000-07-20 Неретин Александр Алексеевич Способ изготовления кальциевой проволоки
FR2871477B1 (fr) 2004-06-10 2006-09-29 Affival Sa Sa Fil fourre
US8221677B2 (en) * 2007-04-02 2012-07-17 Specialty Minerals (Michigan) Inc. Wire injection lance nozzle insert

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Publication number Priority date Publication date Assignee Title
US2577837A (en) * 1949-10-29 1951-12-11 Lothar R Zifferer Introduction of magnesium into molten iron
FR2008407A1 (fr) * 1968-05-13 1970-01-23 Nippon Kokan Kk
US3778250A (en) * 1969-02-26 1973-12-11 Jones & Laughlin Steel Corp Method for treating metallic melts
JPS4936086B1 (fr) * 1969-03-07 1974-09-27
BE795333A (fr) * 1972-03-01 1973-05-29 Thyssen Niederrhein Ag Procede de desulfuration de l'acier en fusion et poche pour sa mise en oeuvre
DE2607947C2 (de) * 1976-02-27 1985-03-14 Fried. Krupp Gmbh, 4300 Essen Beschickungseinrichtung
DE2634282C2 (de) * 1976-07-28 1978-04-13 Mannesmann Ag, 4000 Duesseldorf Verfahren zum kontinuierlichen Einbringen von Zusatzmitteln in ein mit flüssigem Metall gefülltes Gefäß
US4094666A (en) * 1977-05-24 1978-06-13 Metal Research Corporation Method for refining molten iron and steels
JPS5713115A (en) * 1980-06-26 1982-01-23 Komatsu Ltd Production of tough and strong free-cutting ca cast steel

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0273576A1 (fr) * 1986-11-28 1988-07-06 Pfizer Inc. Tuyère pour l'introduction d'un fil de traitement
FR2764905A1 (fr) * 1997-06-23 1998-12-24 Pechiney Electrometallurgie Procede de traitement du plomb fondu par le calcium et fil a base de calcium pour ce traitement
WO1998059082A1 (fr) * 1997-06-23 1998-12-30 Pechiney Electrometallurgie Procede de traitement du plomb fondu par le calcium

Also Published As

Publication number Publication date
ES545813A0 (es) 1986-06-16
DK386284D0 (da) 1984-08-10
AU3178384A (en) 1985-02-14
KR850001921A (ko) 1985-04-10
ES8607407A1 (es) 1986-06-16
JPH0369966B2 (fr) 1991-11-06
ES535098A0 (es) 1986-10-16
DE3472274D1 (en) 1988-07-28
EP0137618A3 (en) 1986-04-02
EP0137618A2 (fr) 1985-04-17
JPH0347909A (ja) 1991-02-28
KR880000468B1 (ko) 1988-04-07
ES8607408A1 (es) 1986-06-16
DK386284A (da) 1985-02-13
AU550957B2 (en) 1986-04-10
BR8404033A (pt) 1985-07-16
ES8700330A1 (es) 1986-10-16
ES545812A0 (es) 1986-06-16

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