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EP0119937A1 - Buse d'injection d'oxygène à jet supersonique stabilisé pour la décarburation des fontes et, en particulier, des fontes au chrome - Google Patents

Buse d'injection d'oxygène à jet supersonique stabilisé pour la décarburation des fontes et, en particulier, des fontes au chrome Download PDF

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Publication number
EP0119937A1
EP0119937A1 EP84420018A EP84420018A EP0119937A1 EP 0119937 A1 EP0119937 A1 EP 0119937A1 EP 84420018 A EP84420018 A EP 84420018A EP 84420018 A EP84420018 A EP 84420018A EP 0119937 A1 EP0119937 A1 EP 0119937A1
Authority
EP
European Patent Office
Prior art keywords
nozzle
oxygen
neck
nozzle according
lateral orifice
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.)
Withdrawn
Application number
EP84420018A
Other languages
German (de)
English (en)
French (fr)
Inventor
Georges Marizy
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.)
Ugine Aciers SA
Ugine Savoie SA
Original Assignee
Ugine Aciers SA
Ugine Savoie SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from FR8302081A external-priority patent/FR2540519A2/fr
Application filed by Ugine Aciers SA, Ugine Savoie SA filed Critical Ugine Aciers SA
Publication of EP0119937A1 publication Critical patent/EP0119937A1/fr
Withdrawn legal-status Critical Current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
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/005—Manufacture of stainless 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
    • C21C7/068—Decarburising
    • 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
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4606—Lances or injectors

Definitions

  • the oxygen injection nozzle which is the subject of the invention, constitutes an improvement on that described in French patent n ° 2 ' 489 368.
  • the nozzle which is the subject of the invention relates to the decarburization of cast irons by means of lances disposed above the level of a bath of liquid iron which emit, through a nozzle , a jet of oxygen towards the surface of this melt.
  • the invention relates more particularly to the decarburization of large volumes of liquid pig iron by means of oxygen injection lances equipped with the nozzle according to the invention.
  • the invention relates especially to the decarburization of chromium cast iron on an industrial scale.
  • the nozzle for the decarburization of cast iron with a supersonic oxygen jet which is described in the patent FR.
  • the essential characteristic of 2,489,368 is a frustoconical divergent whose apex angle is between 60 and 70 ° and preferably between 62 and 66 °.
  • the divergent may comprise, beyond the frustoconical part, a surface of revolution around the same axis, the generating curve of which has a concavity oriented inward.
  • This nozzle has given particularly favorable results for the decarburization of chromium cast irons by applying the method described in the FR patent. 2,474,531. Thanks to its particular shape, it makes it possible to cause the emulsion of cast iron with liquid chromium by the action of the jet of oxygen and by the formation of C0 under conditions which lead to obtaining very high yields. high in Fe and Cr.
  • the nozzle which is the subject of the invention comprises, like that which is the subject of FR. 2,489,368, a divergent.
  • This divergent preferably comprises at least one frustoconical part with an angle at the apex between 60 and 70 °; the wall of the neck of this nozzle has at least one lateral orifice which communicates the interior of the neck with an annular space which surrounds it, which is connected to an oxygen inlet so that at least part of the oxygen which feeds the nozzle penetrates inside the neck through this lateral opening.
  • the frustoconical part of the diverging portion can be extended by a surface of revolution, the generating curve of which has a concavity oriented inward.
  • At least one means of deflecting the oxygen current which penetrates inside the neck through the lateral orifice makes it possible to give a tangential component to its direction of movement, which causes a rotational movement of this current around of the nozzle axis.
  • Such a deflection means may comprise at least one radial partition inclined with respect to the generatrices of the neck, housed in the annular space which surrounds the neck, so as to communicate to the oxygen which traverses this annular space a rotational movement around the axis of the nozzle before entering the interior of this neck through the lateral orifice.
  • the lateral opening is preferably annular; it may possibly itself include a deflection means constituted by partitions making it possible to improve the distribution of the oxygen supply inside the neck, all around the axis of the nozzle, and oriented so as to helping to give the oxygen nets which pass between these partitions a direction of movement comprising a tangential component.
  • the nozzle advantageously includes a second oxygen inlet via an axial passage arranged in the extension of the neck.
  • the oxygen flow rates are preferably adjusted so that at least 50% of the oxygen enters the neck through the lateral orifice.
  • Oxygen can also be introduced into the cervix only through the side port.
  • a fluid other than oxygen such as a hydrocarbon, or else a powder or granular solid such as a carbonaceous material, a metal, a metal oxide or the like.
  • FIG. 1 represents a supersonic oxygen jet nozzle according to the invention with a frustoconical divergent.
  • This nozzle (1) of axis X 1 X 2 comprises a frustoconical diverging portion (2) whose axis is that of the nozzle and whose apex angle (a) is between 60 and 70 °. In the case of the figure, this angle is approximately 65 °.
  • It is supplied by two oxygen inlets A 1 and A 2 , which are each connected to a source of oxygen. The pressure of which is sufficient to allow a supersonic jet to be obtained.
  • the neck (3) of the nozzle consists of a cylindrical tube whose axis is that of the nozzle and inside which opens an annular lateral orifice (4) formed in the vicinity of the connection circumference (5) between the 'downstream end of the inner wall of the neck (3) and the divergent (2).
  • An annular space (6) which surrounds the neck in a substantially coaxial manner is connected to the oxygen inlet (A 1 ).
  • This oxygen current flows through this annular space (6) and enters the neck through the annular lateral orifice (4).
  • the oxygen current moves substantially transversely relative to the axis X 1 X 2 of the nozzle. As soon as it penetrates the neck, it is deflected towards the exit of the neck, then crosses the divergent (2).
  • the annular surfaces (7) and (8) which constitute the lips of the annular lateral orifice (4), can either be planes perpendicular to the axis X 1 X 2 , or have an inclination making it possible to give the threads of oxygen a direction which is not contained in a plane perpendicular to the axis X 1 X 2 , but which is more or less inclined with respect to this axis.
  • the upstream end of the neck (3) of the nozzle is connected to a chamber (9) which is itself connected to the oxygen inlet (A 2 ).
  • the oxygen current coming from (A 2 ) flows through therefore the interior (10) of the neck (3), parallel to the axis X 1 X 2 , then meets the current of oxygen coming from (A 1 ).
  • the set of two streams then enters the divergent (2) and crosses it.
  • the nozzle comprises, in known manner, means for cooling by circulation of water through annular spaces (14) and (15) which surround in a substantially coaxial manner the assembly formed by the neck (3) and the wall. outside (11) of the annular space (6).
  • This water, or any other cooling fluid enters (B 1 ) and leaves in (B 2 ) after having traversed the space between the wall (11), the divergent (2) and the external wall (12) of the nozzle.
  • This space includes an annular partition (13) which forces the water entering (B 1 ) to descend into the gap (14) between this partition (13) and the partition (11) so as to come into contact with the wall (2) of the divergent before rising in the gap (15) between the outer wall (12) of the nozzle and the partition (13), then exit at (B 2 ).
  • Such a nozzle makes it possible to very significantly improve the chromium yield, when it is used in the decarburization process of chromium cast irons described in the FR. 2,474,531.
  • this nozzle for the decarburization of chromium melts by means of small test ovens, containing about 60 kg of liquid iron, chromium yields close to 99% are reached.
  • about 70 to 90% of the oxygen is introduced for example through the inlet (A 1 ) so as to make it penetrate inside the neck (3) through the annular lateral orifice (4), while that the rest is introduced through the entrance (A 2 ) and runs through the interior space (10) of the neck (3) parallel to the axis X 1 X 2 before meeting the transverse jet of oxygen coming from the orifice lateral annular (4).
  • nozzles according to the invention of small dimensions, comprising for example a neck diameter of approximately 2 mm, it is more difficult to obtain very good performance in the case of the application of the process to ovens containing several tonnes of pig iron.
  • a first improvement consists in communicating to the oxygen current coming from (A 1 ), which penetrates inside the neck (3) through the lateral orifice, a direction of movement comprising a tangential component which causes a rotational movement of this current around the axis X 1 X 2 .
  • FIG. 2 shows a simple and advantageous means of producing this rotation.
  • This figure partially shows a nozzle (16) provided with a neck (17) which comprises, in the vicinity of the connection circumference (18) of its internal wall with the frustoconical diverging portion (19), an annular lateral orifice (20 ).
  • the annular surfaces (22 and 23) form the edges of the lateral orifice (20) and lie in planes perpendicular to the axis X3X4.
  • the annular space (21) is connected, not shown, by its end superior, with an oxygen supply.
  • the same result can be obtained, as has already been said above in the case of FIG. 1, by means of a single annular lateral orifice whose edges are not planar but inclined relative to a plane perpendicular to the axis X 3 X 4 .
  • the nozzle represented in FIG. 2 comprises, like that of FIG. 1, water cooling through the annular spaces (27 and 28), separated by the partition (29), which surround the neck (17), the annular space ( 21) and the divergent (19).
  • the use of the nozzle according to the invention makes it possible to avoid the formation of solid deposits on the internal walls (19) of the nozzle, originating from projections from the surface of the molten metal bath. It can be seen that this result is due to the fact that the jet of oxygen marries the walls (19) of the nozzle, the veins of oxygen running along these walls having a sufficiently high speed to prevent the impact on these walls (19) of the solid or liquid particles projected from bottom to top from the metal bath.
  • the device according to the invention also promotes the post-combustion of the CO which is released from the metal bath. Indeed, a fraction of the oxygen injected through the nozzle quickly moves away from the axis of the supersonic jet and reacts on the CO already formed which is oxidized to C02. This post-combustion phenomenon allows a faster rise in temperature of the metal bath from the first phase of decarburization and, therefore, faster reaching of the trigger point of the gas / strong liquid emulsion. All other things being equal, the final temperature of the liquid pig iron after decarburization is higher by 100 ° C. when using the nozzle with supersonic oxygen jet stabilized according to the invention instead of a nozzle with non-supersonic oxygen jet stabilized.
  • the nozzle according to the invention When the dimensions of the nozzle according to the invention become particularly large, for the purpose of treating large quantities of cast iron with chromium, or else of unalloyed or low alloyed cast iron, it is advantageous to bring to the nozzle according to the invention a second improvement which consists in providing it with a divergent comprising beyond a frustoconical part a surface of revolution about the same axis whose generating curve has a concavity oriented inward.
  • FIG 3 shows the end zone of such a nozzle.
  • This nozzle (31) like the nozzle (16), is provided with a neck (32) whose internal wall is connected at its lower end (33) to the frustoconical part (34) of the divergent.
  • the oxygen supply takes place, on the one hand, along the neck (32) parallel to the axis X5X 6 of the nozzle and, on the other hand, through the annular lateral orifice (35) coming from annular space (36); a helical partition (37) 'gives the oxygen current which flows through the annular space a rotational movement before this current crosses the orifice (35).
  • the frustoconical part (34) of the divergent angle of 65 ° at the top is connected by its flared end (38) with a surface of revolution (39) which has the same axis X 5 X 6 as the frustoconical part (34).
  • This surface of revolution (39) has a concavity oriented inwards so that the angle which the tangent to the generator makes with respect to the axis X 5 X 6 decreases from the connection zone (38) with the frustoconical part (34) to the outer edge (40) of the divergent.
  • the surface (39) is substantially parabolic.
  • the supersonic oxygen jet nozzle according to the invention having the characteristics of the nozzle (31), is suitable for the decarburization of large quantities of chromium pig iron by the process described in FR. 2,474,531.
  • This nozzle is also suitable for treating other types of cast irons such as low-alloy or non-alloy cast irons.
  • a nozzle according to the invention is used such as the nozzle (16) shown in FIG. 2.
  • This nozzle comprises a neck (17) constituted by a cylindrical tube of 20 mm internal diameter. At its downstream end, this neck is connected to a divergent (19) constituted by a truncated cone of 65 ° angle at the top and 40 mm in height.
  • a lateral annular orifice (20) allows the penetration of oxygen inside the cervix from the annular space (21).
  • the annular surfaces (22 and 23) which form the walls of the lateral orifice (20) are in planes perpendicular to the axis X 3 X4, spaced from each other by 7 mm.
  • the plane of the surface (22) is at a distance of approximately 10 mm from the connection circumference (18) of the internal wall of the neck (17) with the frustoconical diverging portion (19).
  • This nozzle has a helical partition (24) disposed in the annular space (21). It is fixed to the end of a lance, not shown, which supplies it with oxygen by means of two pipes, one connected to the upstream end of the coil, the other connected to the annular space (21). Adjustment means make it possible to adjust the oxygen flow rate through each of these pipes.
  • water inlet and outlet pipes which also run through the lance, make it possible to circulate the water through the annular spaces (27 and 28) which surround the neck (17), the annular space ( 21) and the divergent (19).
  • This nozzle to decarburize a mass of 4.2 t of liquid chromium cast iron whose initial temperature is 1345 ⁇ C, contained in a converter with an internal diameter of about 1.4 m.
  • the lance at the end of which the nozzle is fixed, is arranged so that the axis X 3 X 4 of the nozzle is substantially vertical, the outer edge (30) of the diverging part (19) being at a distance from the 210 mm liquid iron surface.
  • This cast iron has the following initial composition in% by mass:
  • the oxygen supply is carried out from a network under a pressure of 10 bars; the total flow rate is 13.6 Nm 3 / min. A fraction equal to 20% of this flow rate is introduced at the upstream end of the neck and crosses it parallel to the axis X 3 X 4 "
  • the rest ie 80%, is introduced into the annular space (21) and enters the neck through the annular lateral orifice (20).
  • a stabilized supersonic oxygen jet is thus produced according to the invention.
  • the liquid pig iron is initially covered with approximately 40 kg of a CaO-based slag.
  • the temperature of the liquid iron reaches 17C0 ° C and the carbon content 2.6%.
  • the small amount of slag initially present was expelled at the edges of the converter and the jet of supersonic oxygen directly struck the liquid iron.
  • a nozzle such as that represented in FIG. 3 which comprises at the -from a frustoconical part a surface of revolution of the same axis, the generating curve of which has a concavity facing inward.
  • the section of the lateral orifice is approximately 440 mm 2 while that of the neck is 314 mm 2.
  • the ratio of the sections between orifice is preferably maintained lateral and neck between 1.2 and 1.6.
  • the distribution of the total oxygen flow rate between the axial inlet along the neck of the nozzle and the inlet through the lateral orifice can vary within wide proportions.
  • the quantity of oxygen introduced through the lateral orifice is preferably greater than 50% of the total flow.
  • nozzles with a stabilized supersonic oxygen jet according to the invention give particularly favorable results when their divergence consists of a truncated cone with an angle of 60 to 70 ° at the top, it is also possible to produce nozzles according to the invention, the divergent of which has substantially different characteristics.
  • the axial passage through the neck to introduce into the liquid iron fluids other than oxygen, such as neutral or reactive gases, liquids or preferably solids pulverulent or granular. Solids may optionally be entrained through the nozzle by means of a stream of oxygen or other fluid. It is thus possible to envisage introducing, through the nozzle according to the invention, elements or compounds for treating the iron bath or else addition elements making it possible to modify the composition of this iron.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Fishing Rods (AREA)
  • Nozzles (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
EP84420018A 1983-02-04 1984-02-02 Buse d'injection d'oxygène à jet supersonique stabilisé pour la décarburation des fontes et, en particulier, des fontes au chrome Withdrawn EP0119937A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8302081 1983-02-04
FR8302081A FR2540519A2 (fr) 1980-08-26 1983-02-04 Buse d'injection d'oxygene a jet supersonique stabilise pour la decarburation des fontes et, en particulier, des fontes au chrome

Publications (1)

Publication Number Publication Date
EP0119937A1 true EP0119937A1 (fr) 1984-09-26

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EP84420018A Withdrawn EP0119937A1 (fr) 1983-02-04 1984-02-02 Buse d'injection d'oxygène à jet supersonique stabilisé pour la décarburation des fontes et, en particulier, des fontes au chrome

Country Status (10)

Country Link
EP (1) EP0119937A1 (es)
JP (1) JPS59145717A (es)
KR (1) KR840007751A (es)
AU (1) AU2400784A (es)
BR (1) BR8400446A (es)
ES (1) ES285553Y (es)
FI (1) FI840453L (es)
NO (1) NO840414L (es)
ZA (1) ZA84798B (es)
ZW (1) ZW1584A1 (es)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU86322A1 (fr) * 1986-02-25 1987-09-10 Arbed Lance de soufflage d'oxygene
CN102022917A (zh) * 2011-01-04 2011-04-20 马鞍山钢铁股份有限公司 应用于钢材生产的顶枪

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB800833A (en) * 1956-05-29 1958-09-03 British Oxygen Co Ltd Nozzles
FR1202754A (fr) * 1958-04-25 1960-01-13 Arbed Dispositif pour l'injection de produits pulvérulents ou granulés dans un bain métallique
FR1247884A (fr) * 1959-03-03 1960-12-02 Arbed Procédé et dispositif d'injection par le haut de gaz dans un bain métallique
FR93038E (fr) * 1959-03-03 1969-01-31 Arbed Procédé et dispositif d'injection par le haut de gaz dans un bain métallique.
LU57675A1 (es) * 1968-01-25 1969-04-15
FR2207190A1 (en) * 1972-11-17 1974-06-14 Siderurgie Fse Inst Rech Oxygen and powder blowing lance - for steel making, allows relative movement between lance parts
EP0033289A1 (fr) * 1980-01-24 1981-08-05 Ugine Savoie Procédé de décarburation des fontes au chrome

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB800833A (en) * 1956-05-29 1958-09-03 British Oxygen Co Ltd Nozzles
FR1202754A (fr) * 1958-04-25 1960-01-13 Arbed Dispositif pour l'injection de produits pulvérulents ou granulés dans un bain métallique
FR1247884A (fr) * 1959-03-03 1960-12-02 Arbed Procédé et dispositif d'injection par le haut de gaz dans un bain métallique
FR93038E (fr) * 1959-03-03 1969-01-31 Arbed Procédé et dispositif d'injection par le haut de gaz dans un bain métallique.
LU57675A1 (es) * 1968-01-25 1969-04-15
FR2207190A1 (en) * 1972-11-17 1974-06-14 Siderurgie Fse Inst Rech Oxygen and powder blowing lance - for steel making, allows relative movement between lance parts
EP0033289A1 (fr) * 1980-01-24 1981-08-05 Ugine Savoie Procédé de décarburation des fontes au chrome

Also Published As

Publication number Publication date
FI840453A0 (fi) 1984-02-03
FI840453L (fi) 1984-08-05
ES285553Y (es) 1987-03-01
ZW1584A1 (en) 1984-05-30
NO840414L (no) 1984-08-06
BR8400446A (pt) 1984-09-11
AU2400784A (en) 1984-08-09
JPS59145717A (ja) 1984-08-21
KR840007751A (ko) 1984-12-10
ES285553U (es) 1986-06-16
ZA84798B (en) 1984-09-26

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