DE1433425A1 - Method and device for introducing aggregates into a melt - Google Patents

Description

Dr, Expl. |

BROWN FINTUBE COMPANY, Elyria, OMo (V.St.A.)

Method and device for introducing aggregates into a melt.

The invention relates to a method and an apparatus for introducing particles of an additive in molten metal, whereby a thorough distribution of the particles in the metal is to be achieved.

While the invention for introducing a large number of different additives into various Molten metal or other materials can be used

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may, will, in the following, primarily on introducing them of particles of metallic aluminum in molten steel to reduce the steel, or to create of residual aluminum, to control the grain structure or to Alloy the hardened steel and limited to covering the steel in ingot forms.

In the production of steel, for example according to the Siemens-Martin process, it is common to use metallic Add aluminum to the ladle containing the molten steel after it has been tapped from the furnace, or metallic Add aluminum both into the ladle and after the steel has been introduced from the ladle into the ingot mold, to reduce the steel and / or to control its structure or other properties. Usually that will Aluminum metal in the ladle in the form of ingots or large pieces of scrap or scrap are introduced by moving the pieces of aluminum into the molten metal in the ladle Hand thrown in or shoveled in. Aluminum is usually made into ingot form in the form of shot by hand brought in. In both cases the SchröttellGhen are im essentially circular flat pieces, about 6-13 mm Diameter and a thickness of about 3-9 mm. In the production of unkilled steel, metallic aluminum was in the form of shot thrown into the head of the ingot mold filled with molten steel in order to cover the steel and thereby, the outflow of the gases flowing out of the melt

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cut and thereby ensure a solidification of the metal with inclusion of the gases in the steel.

The described, relatively primitive, older methods of introducing aluminum produced essentials Trouble with yourself. For example, it was impossible the relatively small amount of aluminum is sufficiently uniform in the large volume of molten steel in the To distribute pouring ladle in order to react the aluminum with the oxygen contained in the steel or otherwise to combine, to control the grain structure, or to effect an alloy with the steel, and thus the to produce the desired uniformity of the connection or the structure of the steel. In addition, a significant one Part of the aluminum introduced by dripping onto the Soil is lost instead of in the ladle or ingot mold. The loss of aluminum as a result was even more serious from oxidation by the ambient air or by in the Oxygen contained in slag, since up to $ 75 of the Melted steel in the metallic aluminum supplied to the ladle were lost instead of being expedient to carry out to be able to be supplied to the desired function as a reducing agent for the steel.

An object of the invention is to provide an improved method and apparatus by which Particles of one or more additives with a lower density than that of the material of the melt, such as aluminum,

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can be introduced into a melt, such as a steel melt.

Another aim is to create a method by which a certain number of particles is a or more additives, for example aluminum, in a stream of molten metal can be introduced k-ann ', - » which is dumped from the furnace into a ladle under conditions that allow a thorough distribution of the particles effect in the metal without undesired contact of the additive with the ambient air.

Another object of the invention is to provide an improved, fluid controlled cannon for Introduction of particles of the additive into or onto the molten metal under conditions and in precisely controllable manner Amounts that improve even distribution and effectiveness. Furthermore, with such a fluid-controlled Cannon a precisely measured amount of additives, alone or mixed with other additives in a pouring stream of molten steel during its transition from the furnace to the ladle, namely -during one precisely defined period of time and with a particle speed sufficient for a substantial penetration of the melt with the particles ~ In addition, a cannon is to be created by the invention, which the Einbrigung allows a large amount of additive in a short time, and in which aluminum particles or the like. from an easily fillable funnel or the like. Under atmosphere

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can be introduced.

The method according to the invention is characterized by this from that a stream of pest particles of the additive ejected against the surface of the molten metal from a location remote therefrom at a sufficient speed to move substantially all of the particles below the surface of the molten metal.

A cannon is expediently used for ejecting the method according to the invention of a particle stream of solids, which is characterized in that the same consists essentially of a body with an elongated channel of a certain cross-section and a nozzle whose cross-section is smaller than that of the channel which is in communication with the channel in the vicinity of one end of the channel, and that between the nozzle and a source of compressed air a connection is provided, whereby a negative pressure zone is formed in the channel near the nozzle when compressed air is flowed from the nozzle into the channel, and that an orifice is provided for feeding the particles into the channel which opens laterally into the zone of reduced pressure and that the particle feed is in communication with this orifice stands.

Further details of the invention emerge from the following description of the illustrated in the drawing Embodiments.

Pig. 1 shows a plan view of a device of a preferred embodiment of the invention, which is used for

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Introducing metallic aluminum particles into the pouring stream a steel melt home. outflow - from - a Siemens-Martin furnace is used in a ladle.- -....-.

FIG. 2 is a perspective view according to FIG Line 2-2 in Pig. 1, with the upper end of the device and that from the cannon into the pouring stream of molten steel from ^ ejected partial stream, .that from the pouring channel into the Ladle runs down, is shown on a larger scale.

'Pig. Fig. 3 shows a perspective view of the arrangement of the pig. 1 and 2 device used in enlarged scale ..

Pig. Figure 4 is a cross section taken on line 4-4 in Pig. 1 on an enlarged scale.

Pig. Figure 5 is a vertical cross-section, on a further enlarged scale, through the drive portion of the Pig apparatus. 3. ■

Pig. 6 is a cross section taken along line 6-6 in FIG Pig. 5 on the same scale.

Pig. 7 is a perspective view showing another. Embodiment of the device according to the invention for discharging metallic aluminum particles onto the surface of a steel melt Xn ingot molds *

Pig. Figure 8 shows a side view of the Pig device. 7 on a larger scale- '...,. . . .

Pig. 9 shows a cross section of the drive part. the one in Pig. 8 shown. Device that is essentially ent long is shown in the same cut as Pig. 5 in relation

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to Pig's preparation. 3 as well as on the same scale by Pig. 5.

Pig. Figure 10 is a perspective view of the mouth of the tube of Figure 10. 8 shown device, in particular the deflection attachment for deflecting the particles downwards is shown.

1, 2 and 3 is a preferred embodiment the device according to the invention shown. This device 1 is in the Pig. 1 and 2 shown standing on the platform 2 and on the tapping side a Siemens-Martin furnace 3 arranged. This furnace is provided with a normal launder 4 through which a stream 5 of molten steel is discharged in a known manner into the pouring ladle 6 in order to make the steel melt to form in the ladle. Me device 1, which is referred to as the "cannon" in the following, is shown in FIG Pig. 1 when particles 8 of metallic aluminum are fired or outflow into the pouring stream 5 of molten steel shown at its transition into the ladle 6.

How to Get Autr Pig. 3 recognizes, the cannon 1 consists of a funnel 11, the upper end of which is against the The atmosphere is open and therefore easily accessible for pulling and monitoring. The funnel contains a weighed amount of finely divided aluminum particles 8. The aluminum parts. can take the form of ordinary shot particles of the type described above. The hopper 11 is attached to the frame 12, the lower part of which

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part of two wheels 13 is carried. The frame 12 is equipped with two handles 14 for guiding and positioning the device. Also are front and back Provided on the device supports 15 and 16, which serve to support the device during stationary operation. The drive part 17 is attached to the frame under the hopper 11 and receives the aluminum particles from the lower nozzle of the hopper, which is located preferably tapered downwards and inwards in the manner shown, in order to reduce the movement of the aluminum particles as a result of To simplify gravity in the drive part. The drive part 17, which is described in more detail below is, is connected by means of the hose or another suitable line 18 to the control slide 19, the is attached to one of the two handles 14 of the device and can be operated by means of the slide handle 20. The control slide consists of a known valve for the passage of large volumes, which is between a fully open and fully closed position can be regulated in order to regulate the flow of liquid to the drive part 17. The control slide is by means of the hose 21 with a suitable pressure medium source, for example a compressed air source from about 7 atm overpressure, as it is generally available in blast furnace systems.

The other end of the drive part 17 of the device is sealing with one end of a short flexible one Line 22 connected, the other end of which is connected to the feed end

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of the long barrel 23 is connected. This barrel preferably consists of a tube made of heat-resistant Material, such as stainless steel, and has such a length that the hopper 11 and around this Hopper working people are not exposed to heat if the outlet end 24 of the barrel is in its working position is. Appropriately, the run length should not be more than 5 m long so as not to become unnecessarily heavy and no unnecessary flow resistance to oppose the particles shot through the barrel.

How to tell from the detailed drawing of Pig. 4 recognizes aer the outlet part of the barrel 23 is provided with a heat insulating jacket to avoid its destruction or its Damage from excessive heat in its To prevent working position. The heat insulation shown consists of an attached cylinder jacket 25, which is expediently made of a heat-resistant metal, for example stainless steel, and which Surrounds the outlet opening of the barrel 23 over a corresponding length at a certain distance. The cylinder jacket is with an end wall 26 at the outlet end of the barrel 23 and provided with a further end wall 27 at the opposite end of the jacket 25. Various holes 28 in the wall of the front barrel part 23 connect the interior of the barrel with the annular space 29 between the Coat 25 and the barrel. These bores are arranged in the immediate vicinity of the end wall 27 and are small

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enough to have an air passage or the passage of a to allow other medium to flow into the annulus, while the escape of aluminum particles or other additives from the drain is avoided. Different Outlet openings 31 continue to extend through the Cylinder jacket 25 at a certain distance from the openings 28 and are preferably in the vicinity of the front End wall 26 arranged. Got this way a portion of the drive medium in the course 23 through the openings 28 into the space 29 within the cylinder jacket 25 » moves parallel to the barrel in the annular space and cools the adjacent barrel part in order to then move into the Atmosphere through the barrel openings 31 at the end of the run to resign. In this way, the outlet end of the barrel is largely protected from the heat.

In Figs. 5 and 6, the drive part 17 is the Cannon 1 shown on a larger scale in cross section. This part includes a downward tubular Feed line 32 with an interior 33 »which is at his upper end communicates with the bottom of the hopper 11 and at its lower end with the transverse to the pipe 32 extending pipe part 34 'which also has a cylindrical inner passage 35. In the pipe part 34 is the nozzle 36 with the central inner bore 37 arranged with the air supply hose 18 in connection stands. The bore 37 has a smaller cross section than the passage 35 in the tube 34. Preferably

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the nozzle 36 is axially adjustable in the tubular part 34 so that the outlet end 38 of the nozzle along the lower end of the Feed line 33 can be moved, with the mouth of the funnel partially or completely against the Particle flow from the funnel 11 into the line 35 of the Rohrs 34 is lockable. To do this, the nozzle 36 is arranged to be slidable back and forth in the tube 35, whereby it is sealingly guided in this tube. The rear end of the nozzle is provided with an outwardly extending circular flange 39 and a removable collar 41 which is held in place by means of screws 42. The inward one Flange 43 is arranged at the rear end of the actuator between the flange 39 and the collar 41, The actuator 44 is provided with a longitudinal bore 45 which ends in the front part 46 and has an internal thread 47 is provided. The diameter of the bore 45 is larger than the outer diameter of the flange 39 and the front part 46 is releasably connected to actuator 44 to enable assembly and disassembly. The internal thread cooperates with the external thread 48 on the pipe part 34. Appropriately, is on the outer jacket of the actuator 44 a hand wheel 49 is arranged.

If the actuator 44 is rotated by means of the handwheel 49, the outlet end 38 of the nozzle 36 is of the The position shown in solid lines in FIG. 5 "in which the passage opening 33 of the feed line 32 is completely open, into the position in which the passage opening is completely closed - this position is shown in phantom in FIG.

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draws - or moved to any intermediate position. If necessary, means may be arranged the nozzle 36 relative to passage 33 for displaying the position of the outlet opening 38, for example a pointer 50 to the feed line 32 and marks 51 on the A _u ßenwandung the actuator 44th

In order to achieve a high outlet speed of the .Luft from the nozzle 36, the walls of the bore are 37 tapers inwardly at the outlet opening 38 of the nozzle to form at 52 a neck or a mouth 53, the cross section of which is smaller than that of the bore 37 and substantially is smaller than the cross section of the line 35 into which it opens. The purpose of this device is that the drive air or another pressurized medium as it passes through the bore 37 its speed when passing through the opening 53 in the much larger line 35 of the pipe 34 'in the immediate The vicinity of the outlet opening 38 of the nozzle 36 is greatly enlarged. The air emerging from the mouth 53 moves in an outwardly increasing air flow, which is shown schematically by the dashed lines A. is and whose cross-section in the immediate vicinity of the mouth 53 is relatively small and about can be compared with that of the mouth 6, the air flowing in this part at maximum speed. With increasing distance from the mouth, the flow increases

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speed of the air, while the flow cross-section increases, Ms finally the flow the Inner wall of the line 35 reached, wherein the jet speed is reduced.

As a result of these different areas and velocities, the pressure in the area of zone B around stream A is significantly lower than anywhere else in line 35. The individual parts are preferably designed so that the pressure in zone B is lower than that Is atmospheric pressure. This low pressure favors the flow of the aluminum particles 8 or other additive particles from the line 33 into the line 35 of the pipe part 34 as well as the entrainment of these particles in the air stream flowing out of the nozzle 36 and flowing through the pipe 34 into and through the barrel 23 The construction of the parts, in particular the tapered or reduced mouth opening 53, increases the weight of the particles which can be carried away by the air flow and which can be carried on by the run per unit of time when using the same air flow. By using such a narrowed mouth of the nozzle alone, outflow velocities of more than 200% compared to the velocities previously achievable when using such a cannon could be achieved without other changes having to be made.

Another advantage of the inventive

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direction, which the amount of particles quite considerably; increased, 'the can be introduced into and ejected from the cannon is the return line 55 'through which a part the amount of air flowing through the line 34 flows into the line 33 of the particle supply line 32, preferably at the point where the outlet opening of the funnel passes into this line 32. The bypass line 55 is connected to the inner line 35 of the cross tube 34 on one Place in the direction of flow below the confluence of the line 33 in the line 35 and from that described above IT low pressure zone in connection. The return line is with a Branch line 55a provided, which in turn in.die Particle line 35 opens into the line 35 at a certain distance from its confluence. The other branch 55b is with a downwardly directed mouth end 56 within the funnel 11 directly above and in the immediate vicinity provided for the confluence of the funnel 11 in the funnel nozzle 33.

Amazingly, the "use of the Return line significantly increases the speed at which the material is ejected from the device according to the invention can be. Experiments have shown that this line reduces the particle flow by about. 100 wt .- ^ over the one without such Line achievable current increases. While the reasons for this result are not yet fully understood, however, it is believed that the capacity of the cannon according to the

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present invention in the absence of this feature by, limits the total volume of the mixture of air and particles that can flow through the barrel of the cannon. Return line 55 removes some of the air from the line 35 'after it has been used to entrain particles in the air stream, and in doing so a considerable amount has given kinetic energy to the particles. Removal of the air through return line 55 creates on this Wise space for an additional volume of particles in the barrel and also reduces the air resistance in the Run. As the air removed from the line 35 and flowed into the line 33 via the branch lines 55a and 55b has superatmospheric pressure, it continues to act on the particles in and around the mouth of the line 33 and push the particles through line 33 into line 35 in the gun. In addition, the particles in the feed line 33 stirred up enough to prevent the line 33 from clogging. All of these factors work together and thereby increase the cannon's capacity considerably. Appropriately, the Point C, at which the return line 55 converges with the main line 35 of the cannon, in a zone in the direction of flow below the mouth 53 of the nozzle 36, where a superatmospheric Pressure on the walls of the line 35 prevails and where there is already a significant proportion of the kinetic Energy of the air has been transferred to the particles

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is. For a given arrangement and particle size, leaves the optimal place for the confluence of the return line 55 in the line 35 in a simple way to determine experimentally, generally speaking, can be a satisfactory Arrangement as the same in JPig. 5, be dimensioned so that the distance D of the return line 55 in The direction of flow below the confluence of the line 33 is somewhat larger than the maximum diameter of the line 33 is.

The location E, at which the branch line 55a opens into "the particle supply line 33, should be sufficiently removed from the outlet opening of the line 33 into the transverse line 35 to allow compressed air to flow out of the line 55a into the line 35 without affecting the in of the line 33 and thus practically prevent a short circuit of this branch line. With other Y / places there should be sufficient particle thickness between the outlet of the branch line 55a into the line 33 and the outlet of the line 33 into the line 35. The distance I ¹ is equal to or slightly larger than the maximum ■ diameter of the feed line 33 Satisfactory results are achieved with this dimensioning; the optimal distance is expediently also determined by experiments maximum diameter of the conduit

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except in the event that the cannon is to be emptied. The inside diameter of the two branch lines 55a and 55b can be varied considerably; it is preferably about 1/3 of the maximum diameter of the transverse line 35. In the Branch line 55a, a gate valve 56a is installed; Similarly, branch line 55b includes a gate valve 56b for regulating the flow rate of air through each of the two branch lines in accordance with FIG optimal working conditions.

As previously described, both the constricted orifice and the return line 55 raise each on their own the performance of the cannon is quite significant compared to the performance of a cannon without these characteristics. Amazingly it has however, it was found that the combination of these two Characteristics of the cannon's performance in relation to the ejectable particles more than when the two effects are simply added together increased so that large amounts of particles can be produced in a relatively short time without clogging the gun can be thrown out.

By measuring the amount of particles filled into the funnel 11 and determining the flow rate by adjusting the air pressure or adjusting the nozzle 36 or both, it is possible to control the outflow speed or to regulate the outflow volume per unit of time of the cannon precisely. This advantage is especially important when adding of substances in a molten metal of importance.

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For certain purposes it is desirable a clamping foot 57 (see. Figs. 1 and 3) for precise and firm mounting of the barrel 23 of the cannon in a certain position to use in order to achieve a particle ejection of To ensure a certain point from in a "certain direction. The clamping foot 57 shown in FIG. 3 consists from the stationary vertical column 58, which is placed on the floor of the semolina platform, for example by welding, is attached. The column 58 is provided with a pipe socket 59 open at the top, in the side of which a clamping nut 61 can be screwed in. This pipe socket receives the lower end of a vertical pipe part 62, the upper End rotatably carries a further part 63, which by means of Screw 64 is adjustable in any angular position that is off the vertical. That way you can the part 63 carry out practically all adjustments lying within the intended movement. On the top At the end of the part 63, a Uhterplatte 65 is attached, which has a semi-cylindrical recess for receiving the cannon barrel 23 has. The top plate 66 is connected to the bottom plate 65 on one side by means of a hinge 67 and fastened on the other side by means of clamping screws 68 or other suitable quick acting clamping devices. The top plate 66 is also provided with a recess to accommodate the upper half of the cannon barrel.

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As an example of a suitable application in steel production, the device 1, "before the Steel melt from the batch from the Siemens-Martin furnace is poured into the ladle, brought into position and its run is quickly and precisely adjusted by the clamping foot, so that the flow of particles flowing out of the barrel 23 8 crosses the pouring stream 5 of the molten steel flowing out of the spout. Usually the outlet end is of the barrel 23 preferably between about 15 and 92 cm from the limited area of the pouring stream 5, in that the additive is to be shot. The hose line 21 is connected to a compressed air source, which in a steel mill is usually an air supply line that supplies air at a pressure of about 7 atmospheres. The feed hopper 11 is filled with a certain amount of the desired additive, such as aluminum. This amount is preferred determined by calculating the theoretically required amount to achieve the desired effect in the Ohargengang to achieve, whereby the calculated amount is increased by a few percent in order to compensate for any small losses that may occur. From previous experience with the Siemens-Martin furnace, the casting time and the number of Minutes and seconds during which the cannon is used to feed the aluminum or other additives into the pouring stream the molten metal can be operated is determined. Based on previous calibration, the nozzle 36 adjusted to the inflow amount of the additive so too

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control that the desired amount is supplied when the cannon is activated for the specified time. Of the Siemens-Martin furnace is then tapped and the pouring stream of molten steel 5 begins in the usual vertical direction Railway to fall into the ladle 6. A certain time after the beginning of the flow, usually the time which is required to accumulate a desired amount of steel in the ladle, the spool 19 opened and a stream of additive particles 8 exiting the end of the gun barrel 23 at a speed ejected, which is sufficient that the particle flow is conveyed through the air that it is on the pouring stream of the Steel melt impinges and penetrates it. The device is set up for practical reasons all particles enter the pouring stream 5 at a speed sufficient for the particles to enter the stream 5 penetrate to a depth large enough to cause oxidation of the material of the particles by the beam to prevent the air surrounding the molten metal. The cannon is used for a specific, suitable for outflow Amount of additives required time pressed. Preferably, the particle ejection is stopped before the large mass of slag drains from the furnace at the end of the casting process. A small amount of slag that either from the steel in the furnace, or from the reaction of the steel with the lining of the furnace, launder, or ladle arises, is in beam 5 of the molten metal un-

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avoidable. This slag that is not concentrated in jet 5 tends to collect in a thin layer on the surface of the molten metal in the ladle. However, since the particles 8 are shot into the pouring stream 5 while it flows out and essentially out If there is molten metal, the particles do not come into contact with the concentrated mass of slag and leave thus not lost through reaction with the slag, learner some of the particles are lost by falling to the ground. For practical reasons, therefore, essentially all particles taken up by the flowing beam 5 and effectively distributed and utilized in the molten metal.

As a particular example of the above process, imagine the furnace is a 400 ton open furnace Siemens-Martin furnace, the molten contents of which are drained into a suitable ladle in about 5 minutes can be. From the analysis of the metal it is determined that 2 kg per ton or 800 kg of aluminum shot of the type previously described to achieve the desired results required are. This or a larger amount of shot is put into the filler neck of the device 1. It is It is desirable to put some steel in the bottom of the ladle before the aluminum is expelled begins. Therefore, it was determined that the aluminum should be removed in a time of about 4 minutes or in an amount of 200 kg added per minute and the device should be set so that it produces the same amount of aluminum per minute

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ejects. The device is arranged so that their The outlet end is about two feet from the path of molten metal flowing out of the trough of the furnace. The device is also connected to an air line of the system, which supplies a fragrance of around 7 atmospheres. The furnace will then cut off; about 1 minute after tapping, the device is actuated to stop the ejection of aluminum shot into the stream of molten steel falling freely from the furnace trough into the ladle. The device is operated for 4 minutes and pushes aluminum shot in an amount of 200 kg per minute in the freely falling jet from the pouring channel into the pouring ladle Molten metal from. The shooting in of the aluminum is halted before the slag moves from the furnace onto the metal dripping off the ladle.

In such a process, the aluminum particles are lower in density than the steel shot into and below the unlimited surface of the free falling beam 5 of the molten metal, and at the point where the metal is considerably hotter than then in the ladle and where the particles not distracted or otherwise in their access and entry, occurs in the metal can be braked. The complete penetration of the particles into this extraordinarily hot Metal to a substantial depth causes them to melt faster than in any other pail while they are at the same time by the surrounding molten metal in front of the

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Ambient air are protected. Depending on the material size of the particles, their melting can be largely or can be fully achieved before the metal in the pouring stream enters the mass of molten metal in the pouring ladle.

The aluminum is thoroughly melted in the metal distributed both in particulate form and after melting. In the previously Idesis-level procedure were the particles are added substantially throughout the duration of the jet flow in an amount equal to each proportion of the metal essentially supplies the amount of aluminum required for this proportion in the jet. Thus the particles are over distributes the metal flowing in the jet and even these relatively small portions of molten metal, the submerged ones Particles or droplets containing additive are dripped into the jet and thoroughly with the large Mass of molten metal mixed in the ladle. While it is preferable to add aluminum to the jet in an amount which is related to the flow of molten metal in the jet can in many cases be satisfactory Results are achieved when the aluminum is added in a larger amount for a shorter time. In this case, the device is operated for less than the total duration of the flow of the metal stream. Under these In some circumstances, the additive material will be thoroughly dispersed and distributed by the turbulence of the molten metal in the beam 5 itself and when the beam 5 is immersed in the metal by stirring the metal in the

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The turbulence that occurs in the ladle is accelerated.

According to the invention, for the above and for other reasons, aluminum or other additives added to the molten steel on this surface can be thoroughly distributed extremely finely and evenly over the entire mass of the molten steel in the ladle. The finely divided aluminum reacts with iron oxide and with dissolved or bound oxygen in the steel in order to reduce the steel effectively and evenly. Also, when added in a sufficient amount, it effectively acts to alloy or control the grain size with a high degree of uniformity.

Because the invention is a repeated and accurate introduction of a controllable certain amount of additives in which allows a pouring stream with a small volume at precisely adjustable times in the pouring program, it is also possible to obtain wRecoverable results with the to achieve successive batches. Consequently, extensive empirical work that has so far been carried out at the Steel making was required to be completely turned off and the quality of the steel can vary from batch to batch be improved and made more uniform.

For these reasons, the required amounts of the additives can be reduced considerably. This is especially important when large amounts of relatively expensive additives are required.

In the pig. 7 with 10 is another embodiment

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example of a device according to the invention shown, which serves to cover the steel according to another method according to the invention by means of a type of cap. the Device 71 according to the invention stands on the casting platform 72. Various ingot forms 73 are arranged in a row along the platform in a known manner. From the ladle 74, a stream 75 of molten steel is sequentially produced in accordance with a known method The filling of the individual ingot molds is drained. The device 71, which is also used in the following description Sometimes referred to as a "cannon" is shown in its operative position, with particles 8 of metallic aluminum in the upper area of the molten steel 76 in the third filled ingot mold 73 after being poured from the ladle be applied to cover the steel.

The cannon 71 shown in Fig. 8 contains de.n hopper 77, which at its upper end against the The room air is open and serves to accommodate the required amount of aluminum particles 8. The hopper will duroh carried the frame 78, which in turn is mounted on wheels 79 and with handles 81 for guidance and for Positioning the device is provided. The frame further carries the drive part 82 which is in communication with the lower end of the hopper. The rear

End of the Antrie.bsteils 82 is the serving atm with the Sühlauch 83 connectedness ¹ for supplying air under a suitable pressure from about. 7 The air pressure is through the

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Control slide 84 adjustable. The other end is firmly connected to the running part 85. At its mouth end the barrel 85 carries the deflecting part 86 that carries the aluminum particles on their exit downwards from the cannon in a fan-shaped stream into the upper area of the ingot molds forces.

In Fig. 9, the drive part 82 of the cannon is shown in a longitudinal section. On certain points it is it is identical to the drive part 17 of the cannon 1 of the embodiment described above. Identical Parts are therefore provided with the same reference numbers in both exemplary embodiments. The drive part 82 contains a tubular part 34 with a cylindrical inner conduit 35> in which the nozzle 36 with the bore 37 is mounted so that it can be pushed in and out. The bore 37 is smaller than the cross section of the line 35 and is connected to the air supply hose 83. Appropriately the nozzle 36 is axially adjustable with respect to the cross tube 34, so that the mouth end 38 of the nozzle along the lower end or part of the feed line 87 can be moved, which extends upward through the tubular feed line 88 extends into the bottom of the hopper 77 so that the passage 87 partially or even completely against the Particle flow from the hopper 77 into the line 35 of the cross tube 34 can be closed. As with the previous one Embodiment, the rear part of the nozzle 36 has an outwardly along the circumference

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stretching pad 39 and a removable collar 41 held in place by screws 42. Furthermore, a rotatable actuator 4? provided which surrounds the rear part and the rear end of which is provided with an inwardly inclined flange 43 which is arranged between the flange 39 and the collar 41 of the nozzle. The actuator is provided with a longitudinally extending bore 45 and a firmly attached front part 46 with an internal thread 47 which engages in the external thread 48 of the cross tube 34. The handwheel 49 allows manual rotation of the actuator 44, this actuator and the nozzle 36 being adjusted axially with respect to the cross tube 34 by the interaction of the threads 47 and 48. In this way, the outlet end 38 of the nozzle 36 can be moved from the fully open position, the in Pig. 9 is shown fully marked, are moved into the fully closed position shown in broken lines in the same figure. However, the adjustment is possible in any intermediate position in order to control the particle flow from the hopper 73. As in the previous embodiment, a pointer 50 wiakt on the feed line 87 with markings 51 on the outer jacket of the actuator 44 to indicate the position of the nozzle.

The walls of the bore 37 taper at 52 at the mouth end 38 of the nozzle 36, forming an orifice 53 with a cross-section that is smaller

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than that of the bore 37 vw- ^ is much smaller than that of the line 35 into which the mouth opens. Therefore increases the Äntriehsluft or another pressure medium "when flowing through the line 37 in the immediate vicinity of the outlet opening 38 when passing through the narrow orifice opening 53 and through the larger line 35 of the cross tube 34- their speed and flows in a widening SJJaa & l an initially relatively small cross-section in the vicinity of the orifice 53, the cross-section of which increases with increasing distance from the orifice, while at the same time the speed of the flow decreases 8 of the aluminum particles is accelerated from the line 87 into the line 35. As in the previously described embodiment, the weight of the particles entrained by the air stream and thrown out of the barrel 85 can be significantly increased by the arrangement according to the invention.

Likewise, the amount of particles that can be sucked into the cannon and ejected from it can also be very considerably reduced by means of the barrel.

- put spacer 90 to remove a certain Air content of the drive medium at a point between the feed line 87 and the mouth of the barrel 85 raise. The illustrated intermediate piece 90 consists of

'' a tubular double-conical connector,

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so the parts of which are assembled at their wider ends so that one end of the part 90 is connected to the barrel 85 and the other end forms part of the drive part 82. In the conical part, which is closest to the feed line 87, a plurality of elongated air slots 91 are arranged, which extend transversely to the direction of the gun barrel. The slots are so narrow that it is impossible for the aluminum shot to escape through them. The total cross-section of the slots is large enough, however, to ensure an exit of a considerable amount of air which flows through the drive part of the cannon. Surprisingly, the use of this intermediate piece allows the outflow speed of the material to be increased considerably. Experiments have shown that the device 90 mxr distance from the air increases the flow velocity of the particles, inter alia, to 100% by weight, above the flow velocity which can be produced without such an intermediate piece.

The reasons for this result are not clear

not totally understand her, it is believed that the capacity of the cannon according to the invention in the absence of this Feature or the life line 55 of the Aoefuhnangsbeispiel described above by the total volume of the Liift-Teilehengesiischs is limited, that by the cannon bay can flow through. The intermediate piece 90 allows one Distance lazw. Removal of a considerable amount of air the Leitong 35t after it was used to drive the partial

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chen acted in the air flow and in the process gave up a considerable part of its kinetic energy to the particles. The removal of the air thus creates space for an additional volume of particles that can flow through the cannon barrel and at the same time reduces the air resistance in the barrel. The point at which the air slots 91 open into the line 35 is expediently in an area in the direction of flow below the mouth 53 of the nozzle 36 and below the mouth of the line 87, where there is superatmospheric pressure on the walls of the line 35 and where there is a a considerable part of the kinetic energy of the air has already been transferred to the particles. For a given device and size of the parts, the optimal arrangement of the intermediate piece 90 and the air slots 91 can be determined in a simple manner by experiment. While, as described above, the narrowed muzzle and the air removal through the adapter 90 each significantly increase cannon performance beyond what can be achieved without these features, it has been surprisingly found that the combination of these two features increases the performance of the The particles ejected from the cannon are increased significantly more than one would expect from a mere additive combination of the two effects. so that a large amount of particles can be ejected within a relatively short time. In addition, the particles can be ejected at both high and low speeds without

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the cannon is clogged.

The special one in Pig. 9 shown design of the intermediate piece 90 for air removal is advantageous, because this creates a space with an enlarged cross-section into which the air can expand, with at the same time its speed is reduced before it exits through the slots 91. Hence the Arrangement of the slots 91 in the part of the frustoconical Wall possible, which extends in the direction of flow, so that the slots are not directly affected the particles 8 flowing through the intermediate piece 90 are exposed. The slots also become accordingly 91 is not clogged by the particles, nor are passages created for these particles to escape. the Air expansion and the decrease in velocity in the adapter 90 significantly affect the removal of a Amount of air in a favorable manner, at the same time increasing the space available for the particles will.

In Fig. 10, an embodiment of a deflection attachment 86 is shown, which advantageously is attached to the end of the cannon barrel in order to let the aluminum particles escape downwards and while the one in Pig. 7 to accomplish cap formation shown. The deflector 86 includes a rear portion 92 that serves to place on the muzzle opening of the cannon, and has a line that is connected to the slotted outlet

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Let opening 93 at the front lower edge of the deflector attachment 86 is in communication. The opening 93 is designed so that it allows the formation of a fan-shaped stream of particles of aluminum from the gun.

Using the cannon 71 it is possible to quickly and accurately get aluminum particles into the top layer of a To introduce molten metal in the ingot form, it being sufficient to open the mouth of the cannon only once or lower it twice against the surface of the melt. The particles are uniformly distributed and penetrate into the molten steel so that they effectively cover the entire surface of the molten metal and the formation favorably influence the desired solidified mass structure. In addition, the process according to the invention consumes less aluminum than the previous one method used, as the aluminum is dispensed precisely at the required points, with no potting on · the floor or the space around the ingot shape is to be feared. In addition, enable the device according to the invention and the method provides increased safety since it is no longer necessary to have a worker close to the molten metal in the ingot form.

In a typical procedure according to the invention the device is used to cover each individual ingot of a series of ingot shapes that are in the in own. 7 can be filled from a ladle. It is particularly advantageous to proceed in this way

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that in each case the third ingot mold after that of the casting

pan-filled is provided with a protective cap, as there is enough time to start with this division of labor and there is progression of the turbulent formation of a "killed steel" to the desired degree before the steel is deposited and this calming by the addition of aluminum is modified. It is also possible to melt the metal in a known 15-ton capacity Ingot mold with 7.5 kg of aluminum distributed over the unlimited surface of the molten metal at the head of the ingot mold by means of a single lowering of the mouth opening of the cannon 71 for a period of 6 or 7 seconds. This covering is effective and reproducible, to produce the desired ingot structures with considerable savings in time, labor and aluminum.

From the above it can be seen that the invention provides a method and an apparatus be that the significant, so far with older methods and devices for introducing additives in or fix existing problems on molten metal. The device is simple and largely against in its construction Incorrect operation secured and can be designed to withstand the tough demands that they in blast furnace plants and other metal melt processing plants.

The invention has been described in connection with the addition of aluminum to steel. However, it must

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It should be noted that they are also used for the "Introduction other additives either alone or in a mixture in Steel or other melts can be used. Examples of other additives are lime, calcium carbonate, various kinds of finely divided alloy metals and the like.

Claims

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Claims (15)

~ 35 ~ 143342b claims 1) Method of introducing solid particles into a finely distributed aggregate in a molten metal with unlimited surface, the density of the aggregate is less than that of the metal, characterized in that a flow of solid particles of the aggregate against the Surface of the molten metal ejected from a location remote therefrom at a sufficient speed to move substantially all of the particles below the surface of the molten metal. 2) Method according to claim 1, characterized in that that the particle flow is introduced into the metal during its turbulence. 3) Method according to claim 1 or 2, characterized in that the metal melt during introduction of the particle flow is essentially free of slag. 4) Method according to one of claims 1 to 3 »characterized in that the particles in a pouring stream the molten metal are introduced. 5) Method according to claim 4, characterized in that the amount of metal inflow is determined by the pouring stream is, and that the aggregate is supplied to this in a quantity practically during the entire duration of the pouring stream is that each small amount of metal in the pouring stream is added to the amount corresponding to this amount of aggregate. 809809/0452 6) Method according to one of claims 1 to 5, 'characterized in that the molten metal is made of steel and the particles of the aggregate are made of aluminum. 7) Method according to claim 6, characterized in that the steel melt from a Siemens-Martin furnace is introduced into a ladle in free fall, and that the aluminum particles are shot into this stream will. 8) Method according to claim 1 or 2, characterized in that an ingot mold is filled with molten steel and then a stream of aluminum particles downward from a location above the surface of the molten metal is ejected in the ingot shape. 9) Method according to claim 8, characterized in that dieBiaöüigujag in the steel for a certain period of time the introduction of the aluminum particles into the steel is allowed. 10) cannon for ejecting a stream of solid particles, characterized in that the same substantially consists of a body with an elongated channel of a certain cross-section and a nozzle, the cross-section of which is smaller than that of the channel, and which communicates with the channel in the vicinity of the one end of the channel, and that between the nozzle and a compressed air source a connection is provided, whereby a negative pressure zone is formed in the channel near the nozzle when compressed air from the nozzle in - 3? 809809/045: the channel is flowed in, and that an orifice is provided for feeding the particles into the channel, the opens laterally into the zone of reduced pressure, and that the particle feed communicates with this orifice stands. 11) cannon according to claim 10, characterized in that the maintenance in the channel wall in the direction of flow Nozzle and the mouth for the outflow of part of the compressed air from the channel an opening is provided. 12) cannon according to claim 10 or 11, characterized in that the nozzle in the channel of a position in which the mouth is completely closed, can be adjusted to a position in which the mouth is completely open. 13) cannon according to claim 11, characterized in that a feed line is provided for the particles, which in turn opens into the mouth, and in which a return line is provided which extends between the feed line and the opening in the channel wall, and that through this line removes part of the compressed air from the duct and transfers it to the feed line. 14) cannon according to claim 12, characterized in that the upper end of the feed line is in communication with the hopper containing a particle supply. 15) cannon according to claim 13 _t, characterized in that two return lines are provided between the channel and the feed line. 809809/0452