DE2222830A1 - Arrangement for atomizing molten metal - Google Patents

Description

PATENT LAWYERS.

L-iNG. H, MlSSLiNG ⁶ ? Pouring, | ·

D! PL-iNG, R. SCHLEE Bo a / Hn. 11 .1 55 D (V-ING. J. BOECKER

Allmänna Svenska Elektriska Aktiebolaget Väste ras / Sweden

Arrangement for atomizing molten metal

The present invention relates to an arrangement for Atomizing a metal or metal alloy die with an oven that can be emptied into a semolina pan, and with a cooling section, the oven and pouring pan together in a vacuum and / or protective gas container with at least e · « are included in a vacuum valve.

IXD-PA 20 57 862.5 describes methods and arrangements for atomizing molten metal by means of the division of a molten metal stream through gas or liquid gas streams, which are directed against the melt stream under high pressure. A first and a second of these splitting beams _r, which are each distributed over a plane, are directed towards one another from two opposite sides of the melt beam at an angle of 25-60 °. The first Zerteilungsstrahl and the melting beam together form an angle of 30-60 °, preferably 4O-45 ^Q. The two splitting jets come into effect at such a distance that the melt jet after contact with the

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first splitting beam due to the kinetic energy it is completely redirected before the still molten metal beam hits the other splitting beam. The melt is broken up into free droplets which, after solidification, form the desired powder particles. Except this one there are also other methods of splitting a melt stream.

To facilitate solidification, the above » Known patent application, gas, preferably inert gas, at low temperature through the dividing parts of the melt blow. The gas circulates in a cooling bell which has the purpose of solidifying the melted particles.

Although normally melts with a low oxygen content is used _r, it may be difficult to prevent the surface of the particles oxidizes} in the atomization of high-alloy steel occurs the problem that the alloying constituents often form very static oxides that are difficult to reduce.

In order to reduce this disadvantage, the furnace and ladle have been placed in a vacuum and / or protective gas container with evacuation devices of the usual type, e.g. with multi-stage steam jet ejector pumps and diffusion pumps, which have a pressure of, for example, 10 Torr in the container, possibly upstream of the protective gases in filling, enable.

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A problem here is completing the atomization part to the ladle after a vacuum valve is opened without losing the vacuum or the protective gas atmosphere and at the same time maintaining all the advantages of an effective atomization system, for example of the type described achieved.

The invention is based on the object of the known arrangement for atomizing a molten metal in such a way that a satisfactory sealing of the Atomizing part to the ladle when opening a vacuum valve is achieved. To solve this problem, an arrangement of the type mentioned is proposed, which thereby is characterized in that the ladle, which is provided with holding elements and a bottom opening, is vertically movable is arranged on the connection member of the cooling part, the ladle in the raised position having a lower space exposed, in which the vacuum valve is slidably arranged for the purpose of closing the container, and that the ladle can be connected to connecting elements in the lowered position, in or on which customary blow-off nozzles for gas or gas / liquid are arranged to break up the melt jet.

Based on the embodiments shown in the i ^ i -juren r: oll 'Ii- irfindun ^ r will be explained in more detail. Show it:

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BAD ORiGtNAL

Pig. 1 a detail of the ladle, furnace and atomizing part,

Pig. 2 shows an “overall view of the atomization plant.

In a vacuum container 11 (partially shown in Pig. 1) is an oven 12 for keeping warm, possibly also for heating a Melt, e.g. high-alloy steel, arranged tiltable, the furnace can be a crucible furnace with a low or high frequency coil be. In special cases, a stirrer can also be attached to this furnace or the single-phase feed stream can be activated Switch over the multiphase stirring flow to enable degassing of the melt in the vacuum container (pressure e.g. 10 Torr).

The melt is poured from the furnace 12 into a ladle 15, which is possibly water-cooled and exchangeable as well as with warming organs, e.g. one or more induction coils 14 » is provided to prevent the solidification of the melt in the main space of the ladle and in its bottom opening 15. The warming organs enable long movement times in the pan and tapping at the desired rate, continuously or discontinuous. This is essential as it often takes a long time to tap.

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The figure shows the ladle 13 in the lowered position, but the melt from the furnace % Z can also be poured into the ladle if this is in the dashed position 16 (see double arrow, position A). In an elevated position, a space 17 is exposed under the ladle, in which a vacuum sealing valve 18 in sealing. Position for the container 11 can be pushed.

After opening the valve 18, the semolina pan 13 can be lowered into a centered position on the container wall 19. The pan is centered there with the help of conical pins 20, wherein Pin or hole on the underside of the pan and corresponding holes or pins on the container wall or on the with these connected parts are arranged.

The pan 13 has a lower connector or sealing ring 21, which is lowered to one of the atomization parts containing sealing ring 22 is connected, in which there is a central opening 23 for the melt jet as well as blow-out nozzles 24, 25 for inert gas (argon, nitrogen etc.) to break up the melt jet into droplets (see above). The sealing ring 22 is on a gas supply part with gas supply lines, some of which are arranged in a ring (27, 28), detachably attached. The sealing ring 22 and the part 26 are arranged on an annular plate 29 which a connection part to a cooling arrangement (cooling bell 30, ·

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Granulation tank) and is connected to this by means of an elastic bellows 31, whereby vertical movements the cooling bell 30 or the connection organs 22, 26 are possible. The sealing ring 22 and the part 26 can be firmly or detachably connected to one another.

The bellows 31 is also in lig. 2, as well as the vacuum container 11, the furnace 12 and the ladle 13. The motor for tilting the furnace is indicated at 32. As can be seen, is the entire vacuum part can be displaced in relation to the cooling bell 30.

The arrangement works in the following way: After the furnace 12 has been disconnected, the vacuum valve 18 between the container 11 is opened and the cooling bell (granulating container) 30 are closed. Meanwhile, a cooling box 33 is under with the help of a cart the cooling bell 30 placed. In connection with this, the cooling bell is moved upwards with the aid of hydraulic organs 35 pressed against the bellows 31. The cooling bell is evacuated to about 1 mm Hg, after which it and the cooling box 33 with inert gas (Argon) to be filled to atmospheric pressure. Thereafter, the evacuated vacuum container of the furnace is filled with inert gas Pressure filled and the vacuum valve 18 between the container 11 of the furnace and the cooling bell 30 is opened. The ladle 13 (possibly one of several) is filled and in its lower

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Brought location. Argon gas is connected to the nozzles 24,25 and granulating can begin., Bach pouring and granulating the valve 18 between the vacuum container 11 and the cooling bell 30 is closed.

Vacuum container and cooling bell (granulation container) of the furnace are evacuated and filled with air. The water-cooled The ladle is changed if necessary, and the cooling bell is raised (at 35), "and the lower part with the Cooling box 33 is cleaned by means of transport organs 36 for two purposes pushed aside. The cleaning is due to the accumulation of dust on the cooling box and when changing the alloy before next set of granulation required.

The cooling bell can possibly be equipped with a suction fan and cyclone to remove dust.

After cooling, the powder is sifted into a transport container.

Filling argon into the cooling bell (granulation container) can be done via the cooling box 33.

After melting and granulating, the argon gas is sucked out of the cooling bell 30, e.g. via the cyclone, the

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a not inconsiderable part of the dust particles in the argon gas takes away. The outlet of the cooling bell also has a Vacuum valve.

The arrangement according to the invention can be used within the scope of the following Claims can be varied in many ways. E.g. all or part of the atomization can be done under vacuum instead of a protective gas atmosphere.

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Claims (6)

Claims; 1. Arrangement for atomizing a metal or metal alloy melt with an oven that can be emptied into a pouring ladle, as well as with a cooling part, with oven and pouring ladle together in a vacuum and / or protective gas container with at least a vacuum valve, characterized in that the ladle (13), which is provided with holding elements (14) and a bottom opening (15) provided M, vertically movable is arranged on the connecting element of the cooling part (30), the pouring ladle having a lower one in the raised position Space (17) is exposed in which the vacuum valve (18) for the purpose of closing of the container is arranged displaceably, and that the pouring ladle can be connected to connecting elements in the lowered position is, in or on which conventional blow-out nozzles (24 »25) for gas or gas / liquid to break up the melt jet are arranged. 2. Arrangement according to claim 1, characterized in that in the wall of the vacuum container (11) or connected to it Parts and controls are attached in the cooling box, e.g. usable in holes, expediently conical Pins that center the ladle when tapped. 3. Arrangement according to claim 1 or 2, characterized in that - 10 209848/0810 that the connecting organs on the upper part of a cooling bell (30) attached and elastically displaceable in relation to this by means of elastic organs, e.g. a bellows (31) are. 4. Arrangement according to one of the preceding claims, characterized in that a on the upper part of the cooling bell (30) annular flange is arranged, which is carried by the elastic organs and in turn the connection organs and / or the nozzle part or the nozzle parts for blowing out gas wearing. 5. Arrangement according to one of the preceding claims, characterized in that the vacuum container (11) with oven (12) and ladle (13) in relation to the cooling bell (30) Lifting the ladle and closing the valve (18) can be pivoted to the side. 6. Arrangement according to one of the preceding claims, characterized in that the connecting elements consist of a sealing ring (22) with tap opening (15) and gas nozzles (24, 25) exist, as well as a gas supply part (27), which is fixed or is detachably arranged on the ring. 209848/0810 Blank page