US2760859A

US2760859A - Metallurgical flux compositions

Info

Publication number: US2760859A
Application number: US308935A
Authority: US
Inventors: Edward H Graf
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-09-10
Filing date: 1952-09-10
Publication date: 1956-08-28
Anticipated expiration: 1973-08-28

Description

United States Patent 1 2,760,859 NIETALLURGICAL FLUX COMPOSITIONS Edward H. Graf, Cleveland, Ohio No Drawing. Application September 10, 1952, Serial No. 308,935 13 Claims. (Cl. 75-94) The present invention relates generally to the metallurgical art and is more particularly concerned with a novel flux base composition and with the unique metallurgical fluxes including this base composition and having special utility and value in application to aluminum and aluminum base alloys, brasses and bronzes, and ferrous metals including pig iron, malleable iron, cast iron and steel.

In the production and refining of such metals as aluminum and its alloys, brasses, bronzes and ferrous metals, as well as in the use of these metals, as for instance in the foundry, it is customary to employ fluxes of various types to aid in purifying the metal, keeping it clean, or protecting it from oxidizing effects of the atmosphere. The various flux compositions which have been developed and come into use in commercial operations have had deficiencies which others have sought to avoid through varying the flux formulas but which have never hitherto been substantially eliminated or overcome. Thus, where an attempt might be made to increase bath-covering effectiveness of a flux, modification of the flux formula producing this effect could bring about undesirable corrosive action of the flux on the furnace or crucible in which it is used. Similarly, for example, where a flux composition is designed especially to degasify and scavenge sonims from the metal melt, the flux may be instable at the metal temperature and may decompose into undesirable materials.

By virtue of the present invention, the difficulties, disadvantages and shortcomings of the prior art can be overcome and eliminated so that new combinations of advantages of substantial commercial importance can be obtained for the first time in the processing in the molten state of aluminum, aluminum alloys, brasses, bronzes and ferrous metals in general. Moreover, these advantages can be realized and the foregoing difliculties can be overcome without incurring disadvantages partially or completely offsetting these advantages. It is, for instance, no more expensive to make and use the fluxes of this invention than it is to make and use those of the prior art which have been or are being commercially employed. Actually, in some cases the flux compositions of this invention will prove to be substantially less expensive than commercial fluxes used heretofore for the same general purposes. Moreover, by using the fluxes of this invention it is possible to reduce substantially in many instances the length of the treating period to effect purification to the desired extent of a given molten metal.

As applied to aluminum, certain fluxes of this invention are specially suited for use in remelting aluminum in a reverberatory furnace or in a crucible melting pot and in other foundry operations. These fluxes have the advantage that they do not attack or harm either the furnace or the crucible and the further advantage that they quickly scavenge all oxides and dross in the metal and at the same time degasify it. Moreover, these particular fluxes do not have the common disadvantage of conventional aluminum fluxes of combining or reacting with mag-' ice clean furnace and crucible interiors, give high metal yields (rimning about 90% on the average in smelting aluminum scrap), are easily cleaned and skinned, and can be added at the top or the bottom of the charge in the furnace or crucible.

The fluxes of this invention specially suited for use with ferrous metals and the aforementioned basic flux composition have the unusual power to desulphurize molten ferrous metals at surprisingly rapid rates. Moreover, these fluxes are adaptable for use equally advantageously in the electric furnace, in the cupola and in the ladle.

Broadly described, the flux base composition of this invention comprises between about 50 parts and 85 parts of fused alumina, between about 3 parts and about 6 parts of fused titanium dioxide, between about 10 parts and about 40 parts of silicon, and between about 5 parts and about 20 parts of carbon chemically combined with said silicon.

In this flux base composition, the alumina and titanium dioxide are present in the corundum ratio to each other while the silicon and carbon constituents are in the Carborundum ratio to each other. Also, in accordance with the presently preferred practice of this invention, this flux base composition is actually composed of a mixture of corundum and Carborundum in such ratio to each other than the foregoing proportions of the various ingredients are provided for maximum fiuxing effect. I also contemplate, however, the possibility of compounding this flux base composition by direct reaction starting with bauxite, silica sand and coke, rather than first making corundum and Carborundum and then mixing these products together.

In the event that the present base flux composition is prepared or compounded by such direct reaction procedure, the silicon and carbon will be chemically combined with each other and probably the aluminum and titanium dioxide will be chemically combined with the silicon and carbon although the resulting product may not accurately be said to contain either corundum or Carborundum. In any case, however, the ratios of these constituents to each other will be the same whether the direct reaction method is used or whether the composition is compounded of a mixture of corundum and Carborundum, or whether this composition is made in some other manner.

The ratios of these various ingredients to each other, as stated above, are important to consistent successful use of the present compositions and to the realization of the novel advantages of this invention set out hereinabove. In accordance with my findings in cases where one or more of the ingredients has been used in a substantially larger or smaller amount than prescribed above, erratic results are obtained. The limits prescribed above therefore are critical and should be strictly observed. Within these ratio limits there is a particular preferred composition containing about parts of fused alumina, about 4 parts of fused titanium dioxide, about 12- parts of silicon and about 5 parts of carbon.

As another aspect of this invention, novel flux compositions which are especially valuable and useful in application to aluminum and aluminum base alloys comprise in general between about 70 parts and about parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, between about 15 parts and about 20 parts of amorphous carbon, and between about 30 parts and about 15 parts of a flux base composition of the type defined generally and specifically hereinabove. Here, again, the ratios of the several ingredients are, in accordance with my discoveries, important and critical to the successful practice of this invention and tothe consistent realization of the novel advantages and results hereof. Thus, not only should the limits prescribed for the flux base composition be strictly observed in the compounding of these fluxes, but the quantities of the sodium fluoride salt and the amorphous carbon should likewise be closely controlled and kept Within the limits prescribed.

It will be noted that in stating the composition of these special aluminum and aluminum base alloy fluxes the amounts of constituents have been defined in a reciprocal manner. This is due to the fact that in accordance with my preference, the sodium fluoride salt the amorphous carbon are used in larger amounts when the base flux composition is employed in smaller amounts and in smaller amounts when the amount of flux base composition is increased. Accordingly, where about 70 parts of sodium fluoride salt are used, the amorphous carbon is employed in an amount of about 1'5 parts, but the flux base composition will preferably run about 30 parts. Conversely, where about 85 parts of sodium fluoride salt are used, 20 parts of amorphous carbon are used and the flux base composition is present in only about parts.

As still another aspect of this invention, flux compositions having special utility and value in application to brasses and bronzes comprise between about 70 parts and about 85 parts of a potassium fluoride salt selected from the group consisting of potassium silico fluoride and potassium fluoride, between about 15 parts and about parts of amorphous carbon, and between about parts and about 15 parts of the aforesaid flux base composition.

In still another form, this invention comprises a flux composition having special utility and value in appli cation to ferrous metals. Generally, the composition in this instance comprises between about 25 parts and 75 parts of a sodium fluoride salt as described above, and between about 80 parts and 20 parts of a flux base composition as described in general and detail above. Here, again, the ranges stated I have found to be critical insofar as obtaining consistently satisfactory results is concerned. Also, it will be noted that the ratios of the two basic ingredients of this ferrous metal flux are stated in a reciprocal manner to convey the concept that one. of these two ingredients is used in a larger amount where the other one is used in a smaller amount Within the stated ranges. The prefered composition, for example, will contain about parts of a sodium fluorine salt and about 40 parts of flux base composition.

When this ferrous metal flux is compounded, it is some times to advantage to use sodium chloride as a third constituent, between about 20 parts and about 40 parts of sodium chloride being used. This optional additive Will perform a binding function in the mixture as well as materially enhancing its sulphurizing power.

Where the ferrous metal flux is to be used on cast iron, I prefer to employ about parts of the fluorine salt to about 40 parts of fiux base composition, but it will be understood that the ratios of these materials to each other and the amounts employed in compounding the flux may be varied considerably within the stated ranges to suit the flux for special uses and special metals in the ferrous metal field.

In using the foregoing flux compositions of this invention, they may be employed in dry form or in wet form, depending upon the particular flux composition to be used, the manner and type of furnace in which it is to be employed and the desires of the operator. Thus, a flux composition may be used in wet form where brass is the metal involved since there is no tendency for the flux to stick to molten brass and pouring can be accomplished without a special and expensive skimming operation first being carried out. Ordinarily, however, in processing aluminum and aluminum base alloys, a wet flux is not desirable because of the difiiculty of making furnace. Water glass may be employed as a. binder in making riqucttes of these fluxes and in those cases where lime is desired as an ingredient in the flux, a lime slurry may be used in addition to the water glass or in place of it for binding purposes. Sodium chloride and sodium carbonate may also be used individually or in combination with each other or with water giass or lime for binding purposes and for increased desulphurizing effect. it is not essential for consistently satisfactory results to briquette or bag the flux where it is to be used in a reverberatory furnace since normally the flux is added either before or directly after the furnace has been charged with the metal to be melted and thus gains good contact with the in the moiten state.

in using the foregoing flux compositions in accordance with the method of this invention, these compositions are compounded prior to being brought into contact with molten metal which they are to protect and/or purify. '1' he compounding and mixing operations necessary to produce the desired actions and effects of these flux compositions may preferably be carried out prior to the time that the flux is introduced into the vessel in which the molten metal is to be contained during its treatment period. Thus, it will usually be found convenient to mix the flux ingredients together thoroughly and to make the composition into the required physical form prior to its introduction into the furnace, ladle or other metallurgical vessel. Howey r, in ce; -n instances it may be desirable to charge the various ingredients of the flux into the metallurgical vessel and to mix them together therein either prior to the introduction therein of metal to be melted or at substantially the some time that the solid or cold metal is charged. Where the flux ingredients are added separately to molten metal, the foregoing novel advantages of this invention cannot consistently be obtained. Thus, the basic flux composition hereof under certain circumstances in connection with the treatment of certain molten metals is too r fractory to exercise its beneficial effects in an econorm al and practical operation period. To overcome this reluctance of the basic flux composition, amorphous carbon and an alkali metal fluosilicate or fluoride, or equivalent substance, are employed to promote the slugging cf this composition and to bring the entire operation Well into the commercial field. This is exemplified by certain of the special flux compositions of this invention described above.

Broadly speaking, the method of this invention comprises the step, in the treatment of metal in the molten state, of bringing into contact with that metal a flux courprising between about 50 parts and about parts of fused alumina, between about 10 parts a .d about 4-0 parts of silicon, between about 5 parts and about 20 parts of amorphous carbon, and between about 3 parts and about 6 parts of fused titanium dioxide.

The present method, as indicated above, is applicable to open hearth as well as electric furnace operations and may also be carried out in the cupola, the reverberatory furnace and even in the ladles and the molds. The amount of flux used per unit of molten metal being treated will vary depending upon the particular en ployed and also depending upon the kind of metal being treated. Thus, where the metal is primarily or essentially cast iron the flux preferably employed is one comprising between about 60 parts of a sodium fluoride salt and about 40 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina and about parts and about 40 parts of silicon and about 5 parts and about 20 parts of amorphous carbon and about 3 parts and about 5 parts of titanium dioxide. When this flux composition is employed, it will preferably be used in an amount between about 3 lbs. and 10 lbs. per ton of cast iron, with my preference being about 6 lbs. per ton of cast iron. When this composition is employed in the said preferred amount, I have found in actual operations that wtihin six minutes the sulphur content of the molten metal is reduced by 60 points from an original 140 (1.40%) point value.

Where the method of this invention is applied tothe melting down or refinement of steel, a flux of a different composition as set out above is employed and is preferably added at the beginning of the melt-down operation where an open hearth, an electric furnace or a reverberatory furnace is the metallurgical vessel being used, and after the melt-down stage has been reached where the vessel is a cupola or a crucible. Again, though, the fiux is used in an amount between about 3 lbs. and about 10 lbs. per ton of metal, and preferably 6 lbs. per ton.

Those skilled in the art will gain a further and better understanding of this invention on consideration of the following illustrative, but not limiting, examples of operations which have actually been carried out in commercial production, or have been carried out on an experimental or pilot plant basis, or may be carried out in either of these ways. I

Example 1.In a foundry operation, 2500 pounds of bed-down coke were charged into a cupola and the total coke charge to the bed was eventually brought t0 3500 pounds and ignited and immediately thereafter charges made up of 250 pounds of coke, 75 pounds of limestone, 1200 pounds of pig iron, 400 pounds of cast iron scrap, 400 pounds of steel scrap and30 pounds of 50% ferrosilicon added at tapping intervals of 4 minutes until a total of 26 such charges had been made. The total average of sulphur in these charges was 1.40%, the pig iron containing .046% sulphur, the cast iron scrap containing 0.100% of sulphur, and the coke containing 1.00% of sulphur. To determine the desulphurizing power of a typical flux composition of this invention, samples ,of metal obtained from the first of charges and tappings were treated with 3 pounds of sodium carbonate per ton of charge. Charges Nos. 16 to 22, inclusive, were treaded with 99 oz. of flux of this invention per ton of charge, the flux containing 15.4 oz. of the flux base composition described above, 23.0 oz. of sodium fluoride and 61.6 oz. of sodium chloride. Charges 25 and 26 were treated with 57 oz. per ton briquetted flux containing 17.5% of the flux base composition hereof, 26.5% of sodium fluoride and 56% of sodium chloride.

The flux base composition employed in compounding the flux used in this procedure, consisted of about 80 parts of fused alumina, about 4 parts of fused titanium dioxide, about 12 parts of silicon and about 5 parts of carbon, the alumina and titaniumdioxidebeing in the form of corundum and the silicon and the carbon being in the form of Carborundum.

A total of nine samples selected at random were tested for sulphur content following the cooling and solidification of the cast metal. Samples of charges 1, 5 and 10 had a sulphur content of 0.10%, while charges 15, 20 and 22 contained 0.09%. The sample from charge 17 contained 0.08% of sulphur, while the samples from casts of charges 25 and 26 contained only 0.07% sulphur.

Example 2.-In a similar cupola operation, the usual coke bed was charged into the furnace and limestone and iron as pig iron scrap, cast iron and scrap steel were charged into the furnace in layers in the usual manner, a coke layer being sandwiched between alternate limestone and metal layers. A total of five charges of 400 pounds of metal each were employed. Flux of this invention containing the 60% of sodium fluoride and 50% of the flux base composition hereof was charged in tin cans at intervals, the first 5 pounds of flux being placed on top of the limestone layer of the second charge. After the slag was run off the molten iron which collected in the bottom of the cupola, the first metal tap was made and the first test cast was poured. The flux was in contact with the metal of the second charge and cast for a total of 30 minutes but did not contact the first metal prior to the first tapping operation. Another 5 pound charge of flux of this invention of the aforesaid composition was introduced in tin cans on top of the fifth charge and most of the slag was retained in the reservoir of the furnace for the balance of this heat. Approximately 40 minutes after the second tapping operation a third and final tap was made. Analysis of the test samples cast from the three different tappings revealed that the first tap metal (i. e., the blank) contained 0.10% of sulphur, while the second and third tap metal contained 0.07% of sulphur.

The flux base composition employed in compounding the flux used in this procedure consisted of about parts of fused alumina, about 4 parts of fused titanium dioxide, about 12 parts of silicon and about 5 parts of carbon, the alumina and titanium dioxide being in the form of corundum and the silicon and' the carbon being in the form of Carborundum.

Example 3.--In still another foundry operation, coke, limestone and metal were charged into a cupola in the amounts and sequence set out in Example 1, and the metal was melted down and tapped at four-minute intervals corresponding to the charge intervals, as also specified in Example 1. The flux employed, however, was used in the amount of about 10 pounds per ton of metal and consisted of 30% of a flux base composition of this invention, 50% of sodium fluosilicate and 20% of sodium carbonate. The flux was charged in stages, being apportioned and added in briquette form in the required amount with each separate charge of coke, limestone and metal.

The flux base composition used in this operation consisted of about 80 parts of used alumina, about 40 parts of fused titanium dioxide, about 12 parts of silicon and about 5 parts of carbon, the alumina and titanium dioxide being in the form of corundum and the silicon and carbon being in the form of Carborundum. Desulphurizing results obtained in this case corresponded closely with those reported in Example 1 and the metal resulting was quiteclean and pure and free of sonims and gases and the furnace lining was not attacked to a noticeable degree by the flux or resulting slag.

Example 4.-In an operation the same as that described in Examples 1 and 3, still another flux of this invention was employed with highly satisfactory results comparing favorably with those reported above. In this instance, 6 pounds per ton of flux were used and the flux consisted of 25 parts of sodium fluoride and 80 parts of a flux base composition of this invention containing about 50 parts of fused alumina, 3 parts of titanium dioxide, 5 parts of carbon and 10 parts of silicon, the alumina and titanium dioxide being in the corundum ratio to each other and the silicon and carbon being in the Carborundum ratio to each other.

Example 5.In still another cupola operation quite like those of Examples 1 and 3, entirely satisfactory results corresponding to the foregoing examples were obtained by using 3 pounds per ton of a flux containingabout 75 parts of sodium fluosilicate and about 20 parts of a flux base composition containing about parts of fused alumina, about 6 parts of titanium dioxide, about 40 parts of silicon and about 20 parts of carbon, in which the alumina and titanium dioxide were in the corundum ratio to each other and the silicon and the carbon were in the Carborundum ratio to each other.

Example 6.ln carrying out this invention in an aluminum foundry operation using a reverberatory furnace of 65,000 pound capacity, scrap aluminum was charged following a preliminary charge of flux composition of this invention amounting to approximately half the total flux requirements of the ultimate total metal charge. A total of 10 pounds per ton of the flux was employed, subsequent additions of flux being made in stages with or between metal additions and as the metal in the furnace is melted. The flux was in the form of a finely divided mixture, i. e., a powder of less than about 14 mesh size. In accordance with conventional reverberatory furnace practice, once the metal began to melt and collect in the furnace trough, bailing out was begun and continued to transfer the metal to settling pots. The dross was separated and skimmed off with the slag from the surface of the molten metal in the settling pots and the metal was then immediately cast, the total time consumed from the bailing out to the casting step amounting in the preferred practice to but 2 to minutes. in this case the flux employed comprised about 70 parts of sodium fluosilicate, about 15 parts of amorphous carbon and about 30 parts of a flux base composition of this invention containing about 50 parts of fused alumina, about 3 parts of titanium dioxide, about parts of silicon and about 5 parts of carbon, the alumina and titanium dioxide being in the corundum ratio to each other and the silicon and the carbon being in the Carborundum ratio to each other.

Metal prepared in this manner consistently exhibited superior characteristics, being quite clean and free of sonims, gases and other impurities. Also, the skimming operation was easily and quickly carried out and a clean separation of metal and slag was obtained, and while the furnace and crucible were maintained quite clean, they are not attacked by a flux or the resulting slag to any material extent.

Example 7.In another aluminum foundry operation as set out in Example 6, the results of this invention and advantages set out above are to be obtained consistently through the use of a different flux composition which, however, is embraced and included within this invention. The flux employed in this case was used in an amount of 5 pounds per ton and contained about 85 parts of sodium fluoride, about 20 parts of amorphous carbon and about parts of a flux base composition hereof containing about 85 parts of fused alumina, 6 parts of titanium dioxide, 40 parts of silicon and parts of carbon, the alumina and titanium dioxide being in the corundum ratio to each other and the silicon and the carbon being in the Carborundum ratio to each other.

Example 8.In still another non-ferrous metal foundry operation, brass is processed in accordance with this invention to the foregoing advantageous ends with 7 pounds per ton of a flux comprising about 70 parts of potassium fluoride, about 15 parts of amorphous carbon, and about parts of a flux base composition containing about 50 parts of fused alumina, about 3 parts of titanium dioxide, about 10 parts of silicon and about 5 parts of carbon, the alumina and titanium dioxide being in the corundum ratio to each other and the silicon and the carbon being in the Carborundum ratio to each other.

In this operation involving a reverberatory furnace, the same general steps are carried out as those described in detail in Example 6,

Example 9.-Satisfactory results may also be consistently obtained in connection with foundry practice involving treatment of a brass, where the procedure called for in Example 6 is followed but the flux employed is one containing about 85 parts of potassium fluosilicate, about 20 parts of amorphous carbon and about 15 parts of a flux base composition of this invention containing about 85 parts of fused alumina, about 6 parts of titanium dioxide, about parts of silicon and about 20 parts of carbon, the alumina and titanium dioxide being in the corundum ratio to each other and the silicon and carbon being in the form of Carborundum,

In this instance about 5 pounds per ton of the flux composition of this invention is advantageously employed.

Those skilled in the art will understand that in addition to the ingredients and elements of the fluxes of this invention specifically stated herein and in the appended claims, other substances may be used or compounded with the basic constituents so long as these said substances are not detrimental to the metal processing operations involving the use of these fluxes. Thus, as defined in said claims, this invention contemplates the possibility of additions of innocuous or helpful substances for various purposes to the flux compositions hereof.

Herein and in the appended claims wherever proportions or ratios are stated, reference is had to the weight rather than the volume basis.

Having thus described the present invention so that others skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is defined in what is claimed.

What is claimed is:

1. A metallurgical flux composition having special utility in application to aluminum and aluminum base alloys comprising between about 70 parts and about 85 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, between about 15 parts and about 20 parts of amorphous carbon, and between about 30 parts and about 15 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

2. A metallurgical flux composition having special utility in application to aluminum and aluminum base alloys comprising about 70 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, about 15 parts of amorphous carbon, and about 30 parts of a flux base composition containing between about 50 parts and about parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 pants and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined With said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of tbout 12 parts to about 5 parts, respectively.

3. A metallurgical flux composition having special utility in application to aluminum and aluminum base alloys comprising about 85 parts of a sodium fluoride salt selected from .the group consisting of sodium silico fluoride and sodium fluoride, about 20 parts of amorphous carbon, and about 15 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

4. A metallurgical flux composition having special utility in application to aluminum and aluminum base alloys comprising between about 70 parts and about 85 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, between about 15 parts and about 20 parts of amorphous carbon, and between about 30 parts and about 15 parts of a flux base composition containing between about 50 pants and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

5. A metallurgical flux composition having special utility in application to ferrous metals comprising between about 25 parts and about 75 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, and between about 80 parts and about 20 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about-1O parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

6. A metallurgical flux composition having special utility in application to ferrous metals comprising about 25 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, and about 80 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

7. A metallurgical flux composition having special utility in application to ferrous metals comprising about 75 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, and about 20 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

8. A metallurgical flux composition having special utility in application to ferrous metals comprising about 40 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, and about 40 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

9. A metallurgical flux composition having special utility in application to ferrous metals comprising about 40 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, between about 20 parts and about 40 parts of sodium chloride, and about 40 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

10. A metallurgical flux composition having special utility in application to cast iron comprising about 60 parts of a sodium fluoride salt selected from the group consisting of sodium silico fluoride and sodium fluoride, and about 40 parts of a flux base composition containing between about 50 parts and about parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

11. A metallurgical flux composition having special utility in application to steel comprising about 50 parts of sodium silico fluoride, about 20 parts of sodium carbonate, and about 30 parts of a flux base composition containing between about 5-0 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

12. A metallurgical flux composition having special utility in application to brasses and bronzes comprising between about 70 parts and about 85 parts of a potassium fluoride salt selected from the group consisting of potassium silico fluoride and potassium fluoride, between about 15 parts and about 20 parts of amorphous carbon, and between about 30 parts and about 15 parts of a flux base composition containing between about 50 parts and about 85 parts of fused alumina, between about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the silicon and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

13. A metallurgical flux composition having special utility in application to brasses and bronzes comprising about 70 parts of a potassium fluoride salt selected from the group consisting of potassium silico fluoride and potassium fluoride, about 15 parts of amorphous carbon, and about 30 parts of a flux base composition containing between I about 50 parts and about 85 parts of fused alumina, be-

tween about 3 parts and about 6 parts of titanium dioxide, between about 10 parts and about 40 parts of silicon and between about 5 parts and about 20 parts of carbon chemically combined with said silicon, the alumina and the titanium dioxide being in the ratio to each other of about 80 parts to about 4 parts, respectively, and the sili con and carbon being in the ratio to each other of about 12 parts to about 5 parts, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 585,036 Hunt June 22, 1897 946,302 Wolff Jan. 11, 1910 1,479,327 Sicard Ian. 1, 1924 1,777,081 Graf Sept. 30, 1930 2,306,976 Pedersen Dec. 29, 1942

Claims

1. A METALLURGICAL FLUX COMPOSITION HAVING SPECIAL UTILITY IN APPLICATION TO ALUMINUM AND ALUMINUM BASE ALLOYS COMPRISING BETWEEN ABOUT 70 PARTS AND ABOUT 85 PARTS OF A SODIUM FLUORIDE SALT SELECTED FROM THE GROUP CONSISTING OF SODIUM SILICO FLUORIDE AND SODIUM FLUORIDE, BETWEEN ABOUT 15 PARTS AND ABOUT 20 PARTS OF AMORPHOUS CARBON, AND BETWEEN ABOUT 30 PARTS AND ABOUT 15 PARTS OF A FLUX BASE COMPOSITION CONTAINING BETWEEN ABOUT 50 PARTS AND ABOUT 85 PARTS OF FUSED ALUMINA, BETWEEN ABOUT 3 PARTS AND ABOUT 6 PARTS OF TITANIUM DIOXIDE, BETWEEN ABOUT 10 PARTS AND ABOUT 40 PARTS OF SILICON AND BETWEEN ABOUT 5 PARTS AND ABOUT 20 PARTS OF CARBON CHEMICALLY COMBINED WITH SAID SILICON, THE ALUMINA AND THE TITANIUM DIOXIDE BEING IN THE RATIO TO EACH OTHER OF ABOUT 80 PARTS TO ABOUT 4 PARTS, RESPECTIVELY, AND THE SILICON AND CARBON BEING IN THE RATIO TO EACH OTHER OF ABOUT 12 PARTS TO ABOUT 5 PARTS, RESPECTIVELY.