US1077925A

US1077925A - Apparatus for treating molten metals, alloys, and steels.

Info

Publication number: US1077925A
Application number: US687009A
Authority: US
Inventors: Louis Marie Victor Hippolyte Baraduc-Muller
Original assignee: Individual
Current assignee: Individual
Priority date: 1911-08-16
Filing date: 1912-03-29
Publication date: 1913-11-04
Anticipated expiration: 1930-11-04

Description

L. M. V. H. BARADUG-MULLER.

APPARATUS FOR TREATING MOLTEN METALS, ALLOYS, AND STEELS. APPLICATION FILED 141111.29, 1912.

1,077,925. Patented Nov. 4, 1913.

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l W/Wmsfs j VE/VTOR', M4 i M m w 3 OLfZQ/CLH fl/ My L. M. V. H. BARADUO-MULLER. APPARATUS FOR TREATING MOLTEN METALS, ALLOYS, AND STEELS.

APPLICATION FILED MAR.29, 1912.

Patented Nov. 4, 1913.

2 SHEETS-SHEET 2.

flm-w acid or basic furnace, acid or basic Bessemer UNITED STATES- OFFICE- LOUIS MARIE vrc'ron nirromzrn Balsamic-mourn, or rams, salmon;

arrana'rus ron rnna'rriie momma METALS, annoys, AND s'rnnns. 1

Specification of LettersIatent. 7

Original application filed August 16, 1911 Serial No. 644,884. Divided and 1912. Serial-Ho. 687,009.

this application filed larch as,

To all whom it may concern Be it known that I, LOUIS MA InVm'rOR HIPPOLYTE BAnAnUo-MULLnn, a cltlzen of the .epublic .of France, residing in Paris,-

France, have invented certain .new and useful Improvements in Apparatus for Treating Molten Metals, Alloys, and Steels, of which the following is a specification.

-The resent application is a division ofv my ap ication Serial No. 644,384, filed August 16, 1911, and describes and claims an apparatus described and claimed in said application- There are two sources of the gases which exist in metals andalloys and in particular cast steels. One ofthese is the conditions under which the melting furnace (crucible furnace, acid or basic Siemens-Martin furnace) is operated, or the conditions under which the refining furnace (Siemens-Martin,

converter) is operated. The other source is the internal chemical reactions which give rise to gases (for example the chemical reactions of carbonaceous matter on the oxids fused or dissolved in the li uid metal). -It is not possible to distingulsh sharply between these sources of gases since they exist concomitantly and vary only in their respective intensities. However this may be,-'for a given thermal and chemical treatment to maximum quantit;

which a given metal is subjected at a lven temperature in a given 'melting dr r ing furnace there is produced an equilibrium between the quantities of gases derived from the first and second sources respectively, an equilibrium which corresponds with the fused metal or al y and of which animportant port-ion remains in the cold solidified metal.

The gases which are most generally found in cold metals, allo s and steels after they have been subject .to i neous fusion, are hydrogen, nitrogen, car n-mon'oxid; and carbon-dioxid. It is logical to admit that these same gases existed in solution in the melted metals, alloys and'steels and that i only the total quantity, and the relation of each to this total, vary, owing to the fact that the gases escape during the cooling. A study of the formation of these gases and an attempt to realize the condition in which they exist in metals generally show 65 that they are simply dissolved and not in the of gas dissolved in the erated at this moment dissolve in form of stable chemical combinations. In fact the quantity of dissolved gases depends on the nature and the temperature of the fused alloy, on the pressure and on the chemical composition of the external gaseous atmosphere, in' such a mannerth'at tity maybe represented by Q=Kf(MTP) inwhich K is a co-efiicient dependent on the' nature of the'metal, onthe composition A Patented l {ov. 4,1913.

the quan- I of the gases and on the surface of the metal I plains t e fact that metals, alloys and steels melted in a blast crucible furnace contain more gases than the same metal melted in a Y and that steel made in anacid or basic. converter contains more gas than steel of the same composition prepared an acid or basic Siemens-Mariam furnace. In fact in the Bessemer converter orthe Thomas con verter the pr re 'of the blast exceeds-that of the atmosp ere by about 1.5 kilo, so-that there is gaseous supersaturation and superoxidation.

When at the finishing point the oxid produced is reduced by carboh, the gases genpart and increase the proportion o gases in solution in the hot metal. When the liquid metals, alloys and steels cool, they con-. tract, and the pressure set up by the dimi; nution of the volume of the metal increases, at each instant of the cooling, the

pressure of'the dissolved gases, until this pressure becomes sufiiciently great to overcome the atmospheric pressure and theinternal friction, Iwhich oppose the escape of the gases. From this moment the gases .escape regularlyinto the atmosphere untilthe internal friction, which increases rapidly. as solidification proceeds, prevents more and more this escape, Finally the escapeof the gases becomes extremely slow or even imcrucible furnace operatedby natural draft eater possible. Thus the state of equilibrium is attained for ordinary temperature and pres.

sure, and corresponds with a certain proporthe atmosphere. above the metal there areformed in the subjacent still liquid metal pockets wherein the'pressure of the gases may be very much higher than that of the atmosphere even when the ingot is cold.

' Finally a mechanical agitation, notably a gyratory movement, by creating in a liquid metal a centrifugal force, engenders an accumulation of the metal at the periphery and increases the pressure in the metal. This pressure is transmitted to the dissolved gases and expels them in. the form of bubbles which escapefprincipally at the periphery of the moving metal. These phenomena prove the simple dissolution of the gases in the melted metals and the unstable state of equilibrium in which they are until the metal has completely cooled, a state of equilibrium of dissolution which is only attained owing to the influence of atmospheric pressure which opposes all premature disengagement of the gases. It is logical therefore to admit that if one could upset this equilibrium of dissolution by diminishing the external pressure tangentially to the same of the alloy while this is still liquid, it should be possible to extract from the melted alloy all the dissolved gases whatever may be their source. The prob- -lem is particularly worthy of being solved in the case of steels produced in acid or basic converters for such steelsmay contain, even when they are cold 4, 5 or even 10 times their volume of gas according to their chemical composition and the duration of the thermal treatment and the cooling operation to which they are subjected.

The present invention has for its object to provide an apparatus for removing from metals, alloys and steels not only the gases which may be disengaged by the cooling of the metal but those which remain actually occluded in the cold ingots of metal, alloy or steel which have undergone igneous fusion whatever may be the character of the melting furnace or refining furnace used. For this purpose the gases are extracted from the metal, alloy or steel while they are still liquid, that is to say under the best con-' ditions for facilitating the disengagement of the gases, so that ingots or castings are obtalned which are free from dissolved 0ccluded gases and therefore'have a very high degree of compactness and homogeneity. In this manner blow holes and pockets which form in the head of the ingot and thus depreciate'the value of the head to gaseous materials designed for refining themetals and giving them a desired composition have been added in the course of the metallurgical treatment. This removal of the gases from the liquid metals is accomplished by producing in the apparatus above the surface of the liquid metal, alloy. or steel a vacuum substantially complete, for instance, a-vacuum represented by 1 mm. of

mercury or thereabout. Under this high vacuum the gases are extracted from the perfectly liquid metal, alloy or steel ata high temperature.

The gases contained in the melted steel or other metal are extracted under a high vacuum produced by high power reciprocating or rotary pumps, water ejectors, steam or air 'ejectors, or other suitable apparatus of high power, and the withdrawn gases are energetically chilled as soon as they are extracted from the liquid metal. This energetic chilling of the gases extracted, before they arrive at the extracting apparatus, may be produced in different manners such as by atomizing them with steam or cold Water, by circulating them through apparatus analogous to gas washers, or by passing them through-bundles of tubes around which cold brine or other liquid or cold air, gases or vapors are circulated. It is essent al to insist on the special part which this chilling of the gases issuing from the liquid metals plays, because, owingto this the volume of the gases is very much reduced so that the extracting apparatus can remove per unit time a much more considerable weight of gas owing to the small volume of the gas.

The arrangement of the pumps may be varied according to circumstances. Thus they may be in series or in parallel and combinedlor not with water pumps or ejectors.

A combination which gives very good results comprises the application for the extraction of the gases of pumps, which in the first place lower the pressure to a value corresponding With the maximum useful effect of the pumps and then substituting automatically for these'pum-ps vacuum ejectors operated by water or better by steam or compressed air, and adapted to produce finally a substantially absolute vacuum above the liquid met-a1, alloy or steel, the pressure being thus reduced to a millimeter of mercury or thereabout. 7

An embodiment of the invention isillustrated in the accompanying drawings, wherein-' a 7 Figurel illustrates a front elevation of the apparatus with parts in section. Fig. 2

shows a plan of the apparatus with parts in section. Figs. 3 and 4 illustrate details of the apparatus. Fig. 5 illustrates diagrammatically two sets of apparatus arranged to. work in co'tiperation. Fig. 6 is a diagram illustrating different positions of valves in certain stages of the working of the apparatus illustrated in Fig. 5.

Referring to the drawings, the apparatus comprises a vertical cylinder 35 of sheet steel autogenously soldered, containing a bundle of tubes 36 analogous to that of a tubular boiler. These tubes are surrounded. by a cooling fluid which may enter at the top of the cylinder in 37 and leave at the bottom thereof at 38 after having been more or less heated by the bundle of tubes.

The lower part of the cylinder 35 is surrounded by a collar or sleeve 39 (see Fig. 3) made in several segments bolted together. This collar or sleeve is constricted to accommodate between itself and the lower part of the cylinder. a washer ring of rubber or other suitable material 40, for the purpose of making a tight joint. Against this washer ring may be applied a circular flange 41 of the ladle 1 containing the liquid metal or steel which is to be deprived of gases. In order to hermetically close the joint it suffices to mount the ladle 1 on a suitable press and force the said circular flange 41 against the under surface of the rubber washer; for instance the carriage 2 carrying the casting ladle may be brought onto the platform of a hydraulic press 42 situated below the cylinder 35. As soon as the proper degree of pressure has been applied by the hydraulic press the vacuum pumps may be put in action.

The bottom of the cylinder 35 (see Figs. 1 and 3) is preferably inwardly curved so as to form a sleeve of water 43 in contact with the rubber washer 40, so as to prevent alterafixing= solder 49.

the liquid metal under action of the vacuum 1tiolrli of the joint by heat radiated'from the The lower tube plate 44 within the cylinder 35 is situated at such a height in the latter that there is left a space between the surface of the melted metal and this plate sufficient to insure that particles of melted metal 'which maybe ejected from the mass by are cooled in the bundle of tubes so that their temperature falls from say 14501500*to 350300 C.

For the purpose of more completely cooling the gases there may be combined with the cooler just described a second apparatus comprising a cylinder 50 containing a bundle of tubes 51. Cooling fluid, such as chilled brine, is admitted into the bottom part of this cylinder by 5:2 and leaves the latter at the upper part at 53. The two

cylinders

35 and 50 are connected at the top by a suitable pipe 54 so that the gases which are cooled in the first cylinder descend in the second through the tubes 51 which are chilled by the circulating fluid and issue from this second cylinder at its lower part where the pipe 55 communicates with the vacuum pumps. This second apparatus may lower the temperature of the gases to-15 C. or less. The gases then enter the vacuum pumps and the ejectors.

When the extraction of the gases from the molten metal is finished, which is known by the constancy of the vacuum as indicated by a gage, air is admitted into the cylinder 35 above thecasting ladle little by little, either by opening the cylinder directly to the atmosphere or, which is better, connecting it with a second evacuating apparatus mounted in series with the .first so that the vacuum in the one cylinder may serve to evacuate partially the other, so as to diminish the Work of the vacuum pumps in extracting gas from the second evacuating apparatus. When atmospheric pressure isfinally reestablished in the apparatus the hydraulic platfrom 42 is lowered and the casting ladle 1 which now contains a charge of liquid metal free from gas is conducted to the ingot molds.

I The construction of the apparatus arranged to work in series is shown diagrammatically in Fig. 5. Two sets of apparatus are shown as working together. Two threeway cocks are placed one in each of the

pipes

54, 54 connecting the

vacuum cylinders

35, 35 with the

auxiliary cooling cylinders

50, 50. These three-way cocks are connected by a pipe 60.

(1) When it is desired to begin the exhaustion of gases from the metal of ladle 1, the cooks R R are turned to the position 1) Fig. 6. In this position the two

vacuum cylinders

35, 35 are placed in communication and the pressures therein can equalize.

The cocks R R are then turned to the pofrom the metal 'of'ladle 1 has been completed and it is desired to begin the removal of the gases from the metal in ladle 1, the cocks R and R are turned to the position (3 Fig-6. This places the rarefied vacuum chamber 35 in communication with the vac uum cylinder 35 in which the evacuation has not yet begun, and-there results an equalization of pressures, the vacuum in cylinder 35 being partially reduced and a partial vacuum being produced in cylinder 35. The cocks are then turned to the position (4.) Fig. 6, in which position the cylinder 35 is cut oil from the cylinder-35 and connected with its evacuating pumps andejectors through the pipe 55. The ladle 1 is then removed from its vacuum cylinder.

What I claim is 1. Apparatus for removing gasesfrom steel and the like, comprising in combination a vertical vacuum chamber having an open bottom, a removable receptacle for the molten-metal adapted to makeanair-tight joint with the .bottom of said vacuum chamber,

means for pressing said receptacle'upwardly againstihe under side of said vacuum chamber, means for evacuating said vacuum chamber, and means for :rapidly and extensively cooling the air and gases evacuated from said chamber prior to reaching said evacuating means.

2. Apparatus for removing gases from steel and thelike, comprisingin combination a vertical vacuum chamber, a receptacle for the molten metal adapted to make an airtight joint with the bottom-of said vacuum chamber, means for evacuating said vacuum chamber, and means for rapidly and extensively cooling the air and gases evacuated from said chamber prior to reaching said evacuating means, said means having a capacitv of cooling said air and gases to a temperature of approximately 0 C.

3. Apparatus for removing gases from steel and the like, comprising in combination a vertical vacuum chamber having an open bottom, a receptacle for the molten metal adapted to make an air-tight joint with the.

bottom of said vacuum chamber, means for pressing said receptacle upwardly against the under side of said vacuum chamber, .means for evacuating-said vacuum chamber, and means for rapidly and extensively cooling the air and gases evacuated from said chamber prior to reaching saidevacuating means, said means comprising a cylinder having tubes therein for the passage of gases and adapted to contain a cooling fluid around said tubes.

4. Apparatus for removing gases from steel-and the like, comprising in combination a vertical vacuum chamber having an open bottom, a removable receptacle for the molten metal adapted to make an air-tight joint with thebottom of said vacuum chamber,

means for pressing said receptacle upwardly against the under side :of said vacuum cham ber, means for evacuating said vacuum chamber, means for rapidly and extensively cooling the air and .gases evacuated from said chamber prior to reaching said evacuating means, said means comprising a compartment in the upper part of said vacuum chamber adapted to contain a cooling fluid, and tubes passingthrough said compartment through whichwthe air and gases to be cooled are adapted to pass.

5. Apparatus for removing gases from steel and the like, comprising incombination a vertical vacuum chamber, a removable receptacle for the molten :metal adapted to make an air-tight joint withzthe bottom of.

said vacuum chamber, means for evacuating said vacuum chamber, said'vacuum chamber having a plastic -.Washer-ring at its lower end and means Tfor cooling said washer-ring and-said receptacle having a circular flange adapted to fit against said washer, and means for rapidly and extensively cooling the air andgases evacuated from said chamber priorto reachingsaid evacuating means.

-6. Apparatus for removing gases from steel and-the like, comp-rising in combination a vertical vaeuumchamber, a receptacle for the molten metal adapted to make an airtight joint with the bottom of said vacuum chamber, and means for evacuating said vacuum chamber,said vacuum chamber having a water jacket at its lower end to prevent the heat from said'molten metal-receptacle affecting the joint between said receptacle and chamber.

7. Apparatus for removing gases from steel and the like, comprising in combination a vertical vacuum chamber, a receptacle for the molten metal adapted to :make an air- -tight joint with the bottom of said vacuum chamber, means for evacuating said Vacuum chamber, means for rapidly and extensively cooling the air and gases evacuated from said chamber prior to reaching said evacuati-ng means, said means comprising a compartment in.=the'upperpart of said vacuum chamber adapted to contain a cooling fluid, andtubes passing through said compartment through which the air andgases to be cooled are adapted to pass, and asecond cooling apparatus outside of said vacuum" chamber comprising a tubular cylinder having pipes therein for the passage of the air and gases surrounded by a cooling medium.

8. Apparatus for :removing gases from steel and-the like, comprising in combination a vertical vacuum chamber, a receptacle for the molten metal adapted to make an airtight joint with the bottom of said vacuum chamber, and means for evacuating said 'vacuum chamber, said receptacle having a :tap-hole-therein, arefractory plug for closin-g-said-tap hole, and a metal cap outside of said plug adapted to seal said tap-hole against the entrance of air and adapted to be pierced by the molten metal after the refractory-plug is withdrawn.

9. Apparatus for removing gases from stceland the like, comprising in combinationtwo Vertical vacuum fchambers, two receptacles for molten meta-l'ada-pted .to make airtight joints WltlllllB bottoms of said vacuum chambers, and means for evacuating said vacuum chamber, said vacuum chambers being adapted to be placed in communication with one another whereby air in one-chameration is completedtherein.

her, before the beginning of the evacuating operation therein, may be evacuated into said other chamber after the evacuating op- In' Witness whereof, I have hereunto signed my name 1n the presence of two subscribing witnesses.

LOUIS MARIE VICTOR HIPPOLYTE BARADUC-MULLER.

\Vitnesses LUCIEN MEMMINGER, CHARLES MARDELET.