WO2008054243A1 - Procédé d'affinage de l'acier sous vide dans la poche, dispositif correspondant (et variantes) et tubulure destinée à sa mise en oeuvre - Google Patents

Procédé d'affinage de l'acier sous vide dans la poche, dispositif correspondant (et variantes) et tubulure destinée à sa mise en oeuvre Download PDF

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Publication number
WO2008054243A1
WO2008054243A1 PCT/RU2007/000530 RU2007000530W WO2008054243A1 WO 2008054243 A1 WO2008054243 A1 WO 2008054243A1 RU 2007000530 W RU2007000530 W RU 2007000530W WO 2008054243 A1 WO2008054243 A1 WO 2008054243A1
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WO
WIPO (PCT)
Prior art keywords
steel
pipe
ladle
bucket
vacuum
Prior art date
Application number
PCT/RU2007/000530
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English (en)
Russian (ru)
Inventor
Ivan Ivanovich Karpukhin
Andrey Vladimirovich Lukyanov
Aleksandr Vladimirovich Pogozhev
Aleksandr Anatolievich Nemtinov
Albert Pavlovich Schegolev
Alexandr Mikhailovich Sorokin
Original Assignee
Zakrytoe Aktsionernnoe Obschestvo 'prochnost'
Otkrytoe Aktsionernoe Obschestvo 'severstal'
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Publication date
Application filed by Zakrytoe Aktsionernnoe Obschestvo 'prochnost', Otkrytoe Aktsionernoe Obschestvo 'severstal' filed Critical Zakrytoe Aktsionernnoe Obschestvo 'prochnost'
Publication of WO2008054243A1 publication Critical patent/WO2008054243A1/fr

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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
    • C21C7/10—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
    • 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
    • C21C7/072—Treatment with gases

Definitions

  • the invention relates to the field of metallurgy, in particular to methods and equipment for out-of-furnace treatment of liquid metal, and can be used in the production of high quality steel.
  • the most common method of evacuation is the method of vacuum refining liquid steel in a ladle, which involves placing a ladle with liquid steel in a vacuum chamber, sealing the chamber and creating a vacuum therein over the entire surface of the steel (SU 1675371 Al, IPC C21C 7/10, 09/07/91 , RU 2171298 C2, IPC C21C 7/10, 07.27.2001).
  • an inert gas mainly argon
  • the method of vacuum refining in a ladle has several advantages, firstly, it is the simplest known method of vacuum refining, and secondly, when it is vacuumized, the entire surface of the steel placed in the ladle is evacuated, so the steel is processed more evenly, which ensures a guaranteed and reproducible result, i.e. guaranteed quality of steel.
  • vacuum refining of steel in the ladle allows for deep desulfurization
  • SUBSTITUTE SHEET (RULE 26) steel due to intense mass transfer between slag and steel on its surface.
  • the creation of rarefaction above the surface of the steel leads to its boiling, the formation of splashes and overflow of steel through the side of the bucket. Sprays and overflows of steel across the side of the bucket contaminate the vacuum chamber and lead to steel losses.
  • the volume of the bucket corresponded to the volume of the converter taking into account the minimum free side of the bucket, which ensures its safe transportation in the production environment. If it is necessary to use liquid steel evacuation in such plants, it is necessary to produce melts of reduced mass in the ladle, which leads to a decrease in productivity and an increase in the cost of steel.
  • the construction of a new production involving the use of vacuum refining plants in order to use the converter's capabilities in full, it is necessary to significantly increase the dimensions of the bucket and, accordingly, the dimensions of all mechanisms and the building as a whole, which leads to a significant increase in capital costs.
  • Circulating vacuum refining methods are also known in which the vacuum refining unit comprises two nozzles, one of which melts the steel in a vacuum chamber, undergoes a vacuum, and then flows back into the ladle (DE 19923205 Cl, IPC C21C 7 / 10, 11/30/2000).
  • the advantage of these methods is that both processes allow vacuum refining in a bucket with a minimum free board, have a high speed, and steel sprays do not splash out.
  • the disadvantage of these methods is the unevenness of the process throughout the entire volume of the ladle, therefore, the moment of completion of the vacuum refining process is determined only by chemical analysis of steel samples and in each case, to obtain steel with guaranteed properties, the number of vacuuming cycles should be determined from the results of the study.
  • a known method of vacuum refining in which the vacuum cap is connected directly to the upper flange of the bucket with liquid steel (WO 01/86007, IPC C21C 7/10, 11/15/2001).
  • the vacuum lid is equipped with a cylindrical protrusion located above the level of the upper flange of the bucket, which plays the role of a protective shield against splash of slag and steel in the process of evacuation.
  • the disadvantage of this method is that it is very difficult to provide a vacuum-tight connection between the vacuum
  • the closest analogue of the present invention is a method of vacuum refining molten steel in a ladle, which involves pouring molten steel into a ladle, placing the ladle in a vacuum chamber, dividing the steel surface into central and peripheral zones, and creating different rarefaction steel surfaces above these zones (WO 90/10087, IPC C21C 7/10, September 7, 90).
  • the separation of the steel surface in the ladle into the central and peripheral zones is ensured by immersion in the molten (liquid) steel end of the nozzle located directly on the lid of the vacuum chamber. In this case, the separation of the steel surface into these two zones is provided throughout the entire process of vacuum refining.
  • This method allows vacuum refining of liquid steel with a lower height of the free side of the bucket without overflow of liquid steel overboard.
  • this leads to a complication of the process of vacuum refining, an increase in its duration and a decrease in the quality of refining, since in this case there is no mass transfer between the slag located on the surface of the steel in different zones and liquid steel.
  • An object of the present invention is to increase the volume of steel processed in the ladle during the vacuum refining process, to obtain steel with guaranteed properties as a result of processing by intensively mixing steel throughout the volume and mass transfer between slag and liquid steel throughout the volume, and to reduce the duration of the vacuum refining process.
  • SUBSTITUTE SHEET (RULE 26) .
  • the problem is solved in a method of vacuum refining steel, which involves placing a ladle with liquid steel in a vacuum chamber and dividing the steel surface into central and peripheral zones with the possibility of creating zones of varying degrees of vacuum, in which according to the invention a mixing gas is supplied to the ladle with liquid steel for the entire refining process, and in the first stage of the refining process, the vacuum is increased with the same intensity with the same vacuum in each m a moment of time over the entire surface of the steel in the ladle, at the second stage during the beginning of intense boiling of steel, determined by the formation of a gas-slag-metal emulsion on its surface, the surface of the boiling steel is divided into the central and peripheral zones, while a greater degree of rarefaction is created over the central zone, than above the peripheral zone, after which they continue to increase the degree of rarefaction over these zones with the provision of a given difference in the vacuum between them, in the third stage with a decrease
  • Mixing gas is supplied to the ladle with liquid steel from the bottom of the ladle so that gas bubbles come to the surface of the central and peripheral zones in certain areas that occupy part of their surface.
  • ascending flows of liquid steel are organized in the areas of exit of bubbles on the surface of the central and peripheral zones, and in areas free of gas bubbles, descending flows of liquid steel are formed due to the above, intensive mixing of liquid steel in the ladle takes place.
  • SUBSTITUTE SHEET (RULE 26) The surface of the boiling steel is divided into the central and peripheral zones by means of a pipe by immersing the end of the lower end of the pipe in boiling steel to a depth of h pp , and the union of these zones is carried out by raising the pipe to form a gap ⁇ between the end of the lower end of the pipe and the surface of the boiling steel in the bucket.
  • the separation of the surface of boiling steel into the central and peripheral zones is also carried out by lifting the bucket with boiling steel relative to the stationary pipe until the end of the lower end of the pipe is immersed in boiling steel to a depth of h m , and the union of these zones is carried out by lowering the bucket with boiling steel until a gap ⁇ between the end of the lower end of the stationary pipe and the surface of the boiling steel in the bucket.
  • the separation of the surface of boiling steel into the central and peripheral zones is also carried out by raising the surface level of boiling steel in the bucket relative to the pipe until the end of the lower end of the pipe is immersed in boiling steel to a depth of h pp , and the union of these zones is carried out by lowering the surface level of boiling steel in the bucket until the gap ⁇ between the end face of the lower end of the pipe and the surface of the boiling steel in the ladle.
  • the time of the beginning of intense boiling of steel in the ladle is determined by controlling the rise of the gas and slag metal emulsion and its achievement of a predetermined limit level of h ep max , and the time of decrease of the intense boiling of steel is determined by lowering the level of gas and slag metal emulsion below the specified limit level of h ep max -
  • the maximum level of gas-slag emulsion rise is set either relative to the end of the bead side, or relative to the initial level of the surface of liquid steel in the bucket.
  • the end of the lower end of the pipe is immersed in boiling steel at a level of h ep gas-slag metal
  • SUBSTITUTE SHEET (RULE 26) emulsions in the peripheral zone exceeding by 0–200 mm the level of the end face of the lower end of the nozzle, and at the third stage of the process, when these zones are combined, they provide a gap ⁇ between the surface of the boiling steel and the end of the lower end of the nozzle in the range:
  • H cb is the height of the free side of the bucket.
  • the predetermined difference in the degree of rarefaction over the central and peripheral zones of the surface of boiling steel is supported by ensuring the flow of gas-slag emulsion from the peripheral to the central zone around the end of the lower end of the pipe.
  • the predetermined difference in the degree of rarefaction over the central and peripheral zones of the surface of boiling steel is also provided by pumping gas from the cavity of the vacuum chamber in communication with the peripheral zone of the steel surface in the ladle, and / or by supplying an inert gas, such as argon, to the specified cavity.
  • an inert gas such as argon
  • the present invention allows to increase the volume of steel processed in the ladle during vacuum refining, to obtain steel with guaranteed properties throughout the volume by 15 ⁇ 25% and to reduce the duration of the vacuum refining process by 3 ⁇ 15%.
  • the inventive method of vacuum refining steel in a ladle is implemented by means of a device for vacuum refining steel in a ladle, including a vacuum chamber with a lid, a stand for installing a ladle with molten steel and a nozzle configured to immerse the lower end in molten steel, which according to the invention is provided with a screen, the central part of which a pipe is installed, and the outer edge of the screen is made with the possibility of tight placement between the upper end of the vacuum chamber and the flange of its cover, and the system Aci molten steel stirring gas, the inner surface krysh-
  • SUBSTITUTE SHEET (RULE 26)
  • the ki, the upper surface of the screen and the inner surface of the nozzle form a cavity communicating with the vacuum pump and the central zone of the bucket, and the inner surface of the vacuum chamber, the lower surface of the screen, the outer surface of the bucket, and the outer surface of the nozzle form a cavity communicating with the peripheral zone of the bucket.
  • the outer diameter of the lower end of the pipe is selected from the ratio: D to - Yu0 ⁇ D np ⁇ 21 ppmax + d pp + 2 ⁇ p , (3) where D to is the inner diameter of the bucket in the upper part, mm, D np is the outer diameter of the lower end of the pipe , hr max - the maximum distance from the center of the tube to the axis of the bucket, mm, d pp - diameter of the tube, mm, ⁇ p - wall thickness of the lower end of the pipe, mm.
  • the upper end of the nozzle may be equipped with an inspection hole located in its central part and having dimensions that provide video surveillance of the surface of liquid steel in the central zone of the bucket and the introduction of technological additives in the form of solid, powder, and gaseous materials into liquid steel.
  • video surveillance tools for the central and peripheral zones of the bucket can be installed, and pressure sensors for measuring the degree of depression above the indicated zones are installed in the indicated cavities communicating with the central and peripheral zones of the bucket.
  • the inner surface of the lower end of the pipe can be made in the form of a conical surface, the base of which coincides with the end of the pipe or in the form of a surface of revolution, the generatrix of which is a line of constant or variable curvature.
  • the inner and outer surfaces of the lower end of the nozzle can be made in the form of two mutually intersecting conical surfaces, while the base of the inner conical surface coincides with the lower end of the nozzle, the base of the outer conical surface is equal to the outer diameter of the lower end of the nozzle, and its top is directed towards the end of the lower end of the nozzle .
  • the inner and outer surfaces of the lower end of the nozzle can be made in the form of surfaces of revolution, the generators of which are lines of constant or variable curvature.
  • the pipe can be installed with the possibility of vertical movement relative to the screen, while the device is equipped with a vertical movement mechanism located on the screen or on the cover of the vacuum chamber.
  • the bucket stand can be equipped with a vertical movement mechanism.
  • the cover of the vacuum chamber is provided with a flange, while the screen and said flange are interconnected by means of locking elements.
  • the screen in the second embodiment is equipped with an annular protrusion, the inner surface of which together with the outer surface of the lower end of the nozzle form an annular cavity around the latter, while the inner diameter of the protrusion is selected from the ratio:
  • D VK is the internal diameter of the lid of the vacuum chamber
  • ⁇ in is the wall thickness of the protrusion
  • D in is the internal diameter of the protrusion
  • / L is the inner diameter of the bucket in the upper part
  • H in H p -h fk - K, (5)
  • H in is the height of the cavity formed by the protrusion
  • h fK is the distance from the vacuum chamber flange to the end of the bucket side
  • h p is the distance from the end of the pipe to the end of the bucket side.
  • the device is equipped with locking and regulating equipment, providing the ability to connect these cavities with a vacuum pump and gas supply paths and / or locking and regulating equipment, providing the ability to connect these cavities with each other.
  • a device for vacuum refining steel in a ladle includes a vacuum chamber with a lid, a stand for installing a ladle with molten steel and a nozzle connected to the lid and configured to immerse the lower end in molten steel, and the nozzle is provided with a flange made for tight mating with the cover of the vacuum chamber, while the upper part of the nozzle is closed, located above the cover of the vacuum chamber outside its internal space and connected to the vacuum pump, and the lower part l pipe located under the cover inside the vacuum chamber.
  • a device for vacuum refining steel in a ladle includes a vacuum chamber with a lid, a stand for installing a ladle with liquid steel and a nozzle connected to the lid and configured to immerse the lower end in molten steel, the nozzle being provided with a screen made in the form of a flange, the lower edge of which is made with the possibility of tight pairing with the upper edge of the bucket, and is connected to the lid with the possibility of mutual vertical movement.
  • the nozzle may be connected to the cap via flexible connections.
  • SUBSTITUTE SHEET (RULE 26) according to the invention is equipped with a screen mounted above the ladle with molten metal, the edges of which are made with the possibility of tight placement between the end of the wall of the vacuum chamber and its cover, while the pipe is placed perpendicular to the screen and is rigidly connected with it.
  • the pipe may be made in the form of a cylinder and placed in the center of the screen.
  • the screen is made in the form of a metal ring-shaped plate, the perimeter of which corresponds to the perimeter of the vacuum chamber, and a lining is placed on the surface of the plate facing the liquid metal, which can be made of concrete and connected to the metal ring-shaped plate by means of anchors.
  • the pipe includes a metal cylinder rigidly connected to a metal annular vault plate, and a lining placed on the inner surface of the cylinder and on the outer surface of the lower part of the cylinder.
  • the height of the lining on the lower part of the outer surface of the cylinder is limited by the lower surface of the screen (lining).
  • the lining of the nozzle can be made of concrete and connected to the metal cylinder by means of anchors, moreover, the lining of the lower part of the surface of the metal cylinder can be integral with the lining of the screen, and the upper part of the lining of the inner surface of the metal cylinder can be made of brick.
  • the pipe includes a metal cylinder rigidly connected to a metal annular arch plate, a lining placed on the inner surface of the cylinder and on the lower part of its outer surface, and a cylindrical element made of reinforced concrete mounted on the end of the metal cylinder with the possibility of dismantling.
  • the nozzle is equipped with an annular cover installed by means of a guide on its upper end.
  • the guide can be made in the form of a metal ring with a bead along the outer edge, while the inner diameter of the ring is equal to the inner diameter of the nozzle, the board protrudes beyond it, forming a protrusion, and the guide is rigidly connected to the metal cylinder.
  • the cover can be made in the form of a ring of concrete or it contains an upper part made in the form of a metal ring installed in the guide, and a lower part made of concrete, connected to the upper part by means of anchors and adjacent to the inner surface of the metal cylinder, while the lining the inner surface of the metal cylinder does not reach the upper end of the cylinder by an amount equal to the thickness of the lower part of the cover.
  • the nozzle contains cooling means located on the outer surface of the screen or on the outer surface of the nozzle located above the screen, and made in the form of channels.
  • the nozzle is equipped with trunnions located on the edge of the screen for installation on a bucket in a vacuum chamber and removal.
  • the pipe may be connected to the annular plate of the screen by means of stiffeners located radially and adjacent to the upper part of the outer surface of the metal cylinder and the outer surface of the metal annular plate of the screen.
  • the inner surface of the lower end of the pipe may be made as described above.
  • the nozzle made according to the present invention allows for the evacuation of molten metal, in particular steel, in a vacuum installation without overflows with maximum filling of the bucket, while the height of the free side is limited only by the conditions of transportation of the bucket.
  • the use of this device is possible in existing industries with a slight refinement of the vacuum chamber.
  • FIG. 1 - a device for the vacuum refining of steel in a ladle, made according to the present invention, the first option, General view, section.
  • FIG. 2 is a section A-A of FIG. one.
  • FIG. 3 - the specified device, in which the pipe and the screen are a collapsible design, General view, section.
  • FIG. 4 - the specified device with a mechanism for the vertical movement of the pipe, placed on the screen, General view, section.
  • FIG. 5 the specified device with a mechanism for the vertical movement of the pipe located on the lid of the vacuum chamber, General view, section.
  • FIG. 6 - device the second option, General view, section.
  • FIG. 7 - the same, with locking and regulating equipment.
  • FIG. 8 - the same, with the mechanism of vertical movement of the pipe.
  • FIG. 9 - the same, with the mechanism of vertical movement of the bucket.
  • FIG. 10 is a fragment I of FIG. 3, increased.
  • FIG. 11 is the same flow diagram.
  • FIG. 12 is a fragment II of FIG. four.
  • FIG. 13 is a fragment III of FIG. four.
  • FIG. 14 - device the third option, General view, section.
  • FIG. 15 ⁇ 20 - forms of execution of the lower end of the pipe.
  • FIG. 21 - pipe made in the first embodiment with a cover in the form of a ring of concrete, General view, section.
  • FIG. 22 - the same, with a cover containing a metal ring.
  • FIG. 23 is a fragment of FIG. 2, increased.
  • FIG. 25 - pipe made in the second embodiment a General view
  • the device includes a vacuum chamber 1 with a cover 2, a stand 3 for installing a bucket 4 with molten steel 5 and a nozzle 6.
  • the nozzle 6 is configured to immerse the lower end in molten steel 5.
  • the device is equipped with a screen 7, in the central part of which there is a nozzle 6, and the outer edge of the screen 7 is made with the possibility of tight placement between the upper end of the vacuum chamber 1 and the flange 8 of the cover 2 by means of a tight connection (seal) 9.
  • the pipe 6 is mounted vertically and may have a cylindrical or any other shape with a cross section, for example Emer as oval or polyhedron (not shown). In FIG.
  • the pipe 6 and the screen 7 can be made both in the form of an integral structure, and in the form of a collapsible design.
  • the pipe 6 may be provided with a flange 10, which is connected to the screen 7 by means of a tight connection 11, or the pipe 6 and the screen 7 are connected by means of a tight connection 11 without a flange 10.
  • the pipe 6 can be made through, in the form of a hollow cylinder (FIG. 1) or in the form of a cylinder with a partially closed upper end (Fig. 3-5), and the overlap of the upper end of the nozzle can be provided as a whole design, and a removable cover 12.
  • the inner surface of the cover 2, the upper surface of the screen 7 and the inner surface the nozzle 6 form a cavity 13 in communication with a vacuum pump (not shown) and with the central zone 14 of the bucket 4.
  • the inner surface of the vacuum chamber 2, the lower surface of the screen I 1 the outer surface of the bucket 4 and the outer surface of the nozzle 6 form a cavity 15 in communication with the peripheral zone 16 bucket 4.
  • the device is equipped with a feed system in liquid steel of a mixing gas, for example argon, containing gas supply ducts 17 and porous plugs 18 installed in the bottom of the bucket 4.
  • a mixing gas for example argon
  • D np is equal to 3530 mm.
  • the upper end of the pipe 6 is equipped with a viewing hole 19 located in its central part and having dimensions that provide both video surveillance of the surface of the molten steel 5 in the central zone of the ladle and the introduction of technological additives in the form of solid, powder, and gaseous materials into molten steel.
  • SUBSTITUTE SHEET (RULE 26) On the lid of the vacuum chamber 1 can be installed means 20 for monitoring the central and peripheral zones 14, 16 of the bucket 4, and in the cavities 13, 15 in communication with the central and peripheral zones 14, 16 of the bucket, pressure sensors 21 are installed to measure the degree of vacuum over the zones 14, 16.
  • the lower end of the nozzle 6 may have a different shape, as shown in FIG. 15 - 20.
  • the inner surface of the lower end of the pipe 6 can be made in the form of a conical surface, the base of which coincides with the end of the pipe (Fig. 15). This shape of the lower end of the nozzle is preferred when the argon purge plugs are located close to the center of the bucket and / or the diameter of the nozzle has a diameter close to the inner diameter of the bucket and the end of the nozzle is far from the metal surface.
  • the inner and outer surfaces of the lower end of the pipe 6 can be made in the form of two mutually intersecting conical surfaces (Fig. 16).
  • the base of the inner conical surface coincides with the lower end of the nozzle 6
  • the base of the outer conical surface is equal to the outer diameter of the lower end of the nozzle (D np ), and its top is directed to the end of the lower end of the nozzle 6.
  • This shape of the lower end of the nozzle is preferred when the plugs are argon purges are located far from the center of the bucket and / or the diameter of the pipe is much smaller than the inner diameter of the bucket.
  • the inner surface of the lower end of the pipe 6 and / or the inner and outer surfaces can be made in the form of a surface of revolution, the generatrix of which is a line of constant or variable curvature.
  • the shape of the lower end of the nozzle made in the form of a surface of revolution on the inside is preferable in the case when the plugs for argon purging are located close to the center of the bucket and / or the diameter of the nozzle has a diameter close to the inner diameter of the bucket and the end of the nozzle is located far from the surface of the metal.
  • the shape of the lower end of the pipe made in the form of surfaces of revolution both from the inside and from the outside Fig. 18,
  • the pipe 6 can be installed with the possibility of vertical movement relative to the screen 7, while the device is equipped with a mechanism 22 for the vertical movement of the pipe 6, placed on the screen 7 or on the cover 2 of the vacuum chamber 1 (Fig. 4, 5).
  • the stand 3 for installing the bucket 4 may be equipped with a mechanism 23 for the vertical movement of the bucket 4, as shown in FIG. 9. In both cases, any type of vertical movement mechanisms known to those skilled in the art can be used.
  • the flange 8 can be additionally connected to the outer edge of the shield 7 by means of locking elements 24, for example, a type of clamp, as shown in FIG. 12.
  • the screen 7 can be equipped with an annular protrusion 25, the inner surface of which together with the outer surface of the lower end of the pipe 6 form an annular cavity 26 around the pipe 6.
  • the inner diameter D of the protrusion is selected from relation (4):
  • H n the height of the lower part of the pipe
  • h p the distance from the end of the pipe to the end of the side of the bucket.
  • the device is equipped with shut-off and control valves 27, providing both the possibility of connecting the cavities 13, 15 with a vacuum pump
  • SUBSTITUTE SHEET (RULE 26) (not shown) and gas supply paths 16, and the possibility of connecting the cavities 13, 15 with each other, as shown in FIG. 4, 5.
  • shut-off and control valves 27 standard valves known to those skilled in the art can be used. The choice of specific models of fittings depends on the conditions of a particular production and the equipment used.
  • the device according to the present invention includes a vacuum chamber 1 with a cover 2, a stand 3 for installing a bucket 4 with liquid steel 5 and a pipe 6 connected to the cover 2 and configured to immerse the lower end in the liquid steel 5, while in contrast to the first embodiment, the nozzle 6 is equipped with a flange 8 made with the possibility of tight coupling by connecting 28 with the cover 2 of the vacuum chamber 1.
  • the upper part of the pipe 6 is closed, located above the cover 2 of the vacuum chamber measures 1 outside its internal space and is connected to a vacuum pump (not shown), and the lower part of the nozzle 6 is located under the cover 2 inside the vacuum chamber 1.
  • the nozzle 6 has a greater height compared to the nozzle 6 made according to the first embodiment, and can be equipped with a vertical movement mechanism 22 mounted on the cover 2 of the vacuum chamber 1.
  • the device also includes a vacuum chamber 1 with a cover 2, a stand 3 for installing a bucket 4 with liquid steel 5 and a pipe 6 connected to the cover 2 and configured to immerse the lower end in liquid steel 5, with this pipe 6 is provided with a screen 29 made in the form of a flange.
  • the lower edge of the flange is sealed by means of a connection 30 with the end of the bead 4.
  • the screen 29 is connected to the lid 2 with the possibility of mutual vertical movement by means of flexible connections 31.
  • the screen 29 can be made in the form of a half of a torus with a cavity 32 open towards the bucket 4 to catch the spray of steel during boiling.
  • SUBSTITUTE SHEET (RULE 26)
  • the constructions made according to the second and third options may contain video surveillance means 20 for the central and peripheral zones 14, 16 of the bucket 4, pressure sensors 21, mechanisms for vertical movement of the bucket 4 and shut-off and control valves 27.
  • these elements are similar and are intended to perform similar functions.
  • the geometric parameters of similar elements of the device in all three variants are determined in accordance with relations (l) - (5).
  • FIG. Figure 2 shows the region 33 of exit of gas bubbles from a liquid metal in the process of evacuation.
  • FIG. 21-25 shows the design options of the pipe 6.
  • the pipe 6 is equipped with a screen 7, the edges of which are made with the possibility of tight placement between the end of the wall of the vacuum chamber 1 and its cover 2.
  • the pipe 6 is placed perpendicular to the screen 7 and is rigidly connected with it.
  • the pipe 6 can be made in the form of a cylinder and placed in the center of the screen 7.
  • the screen 7 is made in the form of a metal ring-shaped plate 34, the perimeter of which corresponds to the perimeter of the vacuum chamber 1.
  • a lining 35 is placed, which can be made of refractory concrete and connected to the metal ring-shaped plate 34 by means of anchors 36.
  • the pipe 6 includes a metal cylinder 37, rigidly connected to a metal ring-shaped plate 34 of the screen 7, and a lining 38 located on the inner surface of the cylinder 37, and on the outer surface of the lower part of the cylinder 37. In this if the height of the lining 38 on the outer surface of the lower part of the cylinder 37 is limited to the lower surface of the screen 7.
  • the lining 38 is made of concrete and is bonded to the metal cylinder 37 by means of anchors 39.
  • the lining 38 of the lower surface of the cylinder 37 can be integral with the lining 35 of the shield 7, as shown in FIG. 22.
  • the metal cylinder 37 may be made of refractory brick 40.
  • the nozzle 6 includes a metal cylinder 37, rigidly connected with a metal annular plate 34, a lining 38 placed on the inner surface of the cylinder 37 and on the lower part of its outer surface, and a cylindrical element 41 made of reinforced concrete, mounted on the end of the metal cylinder 37 with the possibility of dismantling.
  • the pipe 6 is equipped with an annular cover 42 mounted by means of a guide 43 at its upper end.
  • the guide 43 is made in the form of a metal ring with a flange on the outer edge, while the inner diameter of the ring is equal to the inner diameter of the nozzle 6, and the flange protrudes beyond it, forming a protrusion, and is rigidly connected with the metal cylinder 37.
  • the cover 42 can be made in two versions.
  • FIG. 21 shows a cover 42 made in the form of a ring of concrete.
  • FIG. 22 shows a cover that includes an upper part 44 made in the form of a metal ring mounted in the guide 43 and a lower part 45 made of refractory concrete, connected to the upper part 44 by means of anchors (not shown) and adjacent to the inner surface of the metal cylinder 37
  • anchors not shown
  • the lining 38 of the inner surface of the metal cylinder 37 does not reach the end of the cylinder 37 by an amount equal to the thickness of the lower part 45 of the cover.
  • the device contains cooling means 46 located on the outer surface of the screen 7 or on the outer surface of the pipe 6 located above the screen 7, which are made in the form of channels (Fig. 22, 23, 25).
  • the device is equipped with pins 47 located along the edge of the screen 7, for installation in a vacuum chamber 1.
  • the metal cylinder 37 is rigidly connected to the annular plate 34 of the screen 7 by means of stiffening ribs 48 located radially and adjacent to the upper part of the outer surface of the metal cylinder 37 and the outer surface of the metal annular plate 34 of the screen 7 (Fig. 24).
  • the inner surface of the lower end of the pipe 6 may have any of the forms indicated above.
  • the method was implemented by means of the device shown in FIG. 1.
  • Ladle 4 with liquid steel 5 (smelting mass 345 t) was installed using a bridge crane into the internal cavity of the vacuum chamber 1 on stand 3.
  • chamber 1 with a ladle 4 installed in it was covered with a screen 7 with a cylindrical pipe 6 and a cover 2.
  • Argon was supplied in such a way that gas bubbles came to the surface of the central and peripheral zones 14, 16 in certain regions 33 occupying part of their surface, as shown in FIG. 2.
  • the vacuum control in the vacuum chamber was carried out using vacuum gauges in cavities 13, 15 during the entire vacuum process
  • SUBSTITUTE SHEET (RULE 26) refining. Under the influence of rarefaction from liquid steel, bubbles of dissolved gases — carbon monoxide, hydrogen, and nitrogen — were formed and a gozslag-metal emulsion was formed on the surface of the liquid steel.
  • the rise of gas-slag emulsion was controlled in a ladle 4 (in the peripheral zone 16) through the inspection holes 19 (not shown in Fig. 1) located on the lid 2, during the entire vacuum refining process, and by analyzing the traces of the lifting of a gas-slag emulsion in the ladle 4 relative to the primary level of liquid steel with slag and on the outer and inner surfaces of the pipe 6 (in the Central zone 14).
  • the gas-slag emulsion level decreased, which led to the unification of zones 14 and 16 and as a result of this, the alignment of the vacuum above them.
  • the vacuum continued to increase to a predetermined level, which was in the range from 0.5 to 2 mm RT. Art. Then, the steel was kept under the indicated vacuum for 6 minutes.
  • the level of steel refining was monitored by the content of carbon, sulfur and dissolved gases. The control showed that these indicators correspond to the set, therefore, the repetition of the stages of the process is not required.

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

Abstract

L'invention concerne la métallurgie et notamment des procédés et des équipements destinés à la transformation du métal en fusion en dehors du four et peut s'utiliser dans la fabrication d'un acier haute qualité. Le procédé d'affinage de l'acier sous vide consiste à placer la poche contenant de l'acier en fusion dans une chambre à vide et à séparer les surfaces de l'acier en une zone centrale et une zone périphérique, de manière à pouvoir créer du vide de degrés différents au-dessus de ces zones. Selon l'invention, le procédé consiste à alimenter dans la poche contenant de l'acier en fusion du gaz de mélangeage pendant tout le processus d'affinage; au premier stade du processus d'affinage le degré de vide est augmenté avec une intensité égale de manière à assurer à tout moment un degré de vide identique au-dessus de la surface de l'acier contenu dans la poche; au deuxième stade du processus, au début d'un processus d'ébullition intense de l'acier, qui est déterminé par la formation à sa surface d'une émulsion de gaz, de scories et de métal, la surface de l'acier en fusion est séparer en une zone centrale et une zone périphérique, le degré de vide au-dessus de la zone centrale étant supérieur au degré de vide au-dessus de la zone périphérique; après quoi on continue à augmenter le degré de vide au-dessus de ces zones tout en préservant la différence de vide entre elles; au troisième stade, lors de la baisse d'intensité du processus d'ébullition de l'acier on regroupe de nouveau ces zones et l'on continue à augmenter le degré de vide au-dessus de touts la surface de l'acier jusqu'à un niveau prédéterminé; après quoi on retient l'acier à un degré de vide prédéterminé pendant un temps prédéterminé; on contrôle, au quatrième stade, le degré d'affinage de l'acier dans la poche et, si il dépassée une valeur prédéterminé, on recommence les stades du processus décrit ici jusqu'à l'obtention du degré d'affinage de l'acier prédéterminé.
PCT/RU2007/000530 2006-10-05 2007-10-03 Procédé d'affinage de l'acier sous vide dans la poche, dispositif correspondant (et variantes) et tubulure destinée à sa mise en oeuvre WO2008054243A1 (fr)

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RU2495138C1 (ru) * 2012-05-17 2013-10-10 Открытое акционерное общество Акционерная холдинговая компания "Всероссийский научно-исследовательский и проектно-конструкторский институт металлургического машиностроения имени академика Целикова" (ОАО АХК "ВНИИМЕТМАШ") Способ внепечной обработки жидкой стали
RU2651097C2 (ru) * 2016-07-04 2018-04-18 Федеральное государственное унитарное предприятие "Центральный научно-исследовательский институт черной металлургии им. И.П.Бардина" (ФГУП "ЦНИИчермет им.И.П.Бардина") Устройство для вакуумирования металла
CN113957203B (zh) * 2021-12-21 2022-03-15 太原科技大学 一种多功能非中心对称真空精炼设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990010087A1 (fr) * 1989-02-24 1990-09-07 Mannesmann Ag Procede et dispositif de traitement de metaux dans le vide
RU1547323C (ru) * 1988-03-01 1994-12-30 Нижнетагильский металлургический комбинат Способ внепечного рафинирования металлического расплава
RU2173715C2 (ru) * 1999-11-15 2001-09-20 Открытое акционерное общество "Северсталь" Способ обработки металлического расплава и устройство для его осуществления
WO2001086007A1 (fr) * 1998-12-21 2001-11-15 Nippon Steel Corporation Dispositif d'affinage a poche de coulee et procede d'affinage a poche de coulee correspondant

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU1547323C (ru) * 1988-03-01 1994-12-30 Нижнетагильский металлургический комбинат Способ внепечного рафинирования металлического расплава
WO1990010087A1 (fr) * 1989-02-24 1990-09-07 Mannesmann Ag Procede et dispositif de traitement de metaux dans le vide
WO2001086007A1 (fr) * 1998-12-21 2001-11-15 Nippon Steel Corporation Dispositif d'affinage a poche de coulee et procede d'affinage a poche de coulee correspondant
RU2173715C2 (ru) * 1999-11-15 2001-09-20 Открытое акционерное общество "Северсталь" Способ обработки металлического расплава и устройство для его осуществления

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