US1727180A - Vanadium-aluminum-silicon alloy - Google Patents

Description

Patented Sept. 3, 1929.

UNITED. STATPESA 1,727,180 PATENT OFFICE;

BYR AMJ'I D. SAKLATWALLA, OF GRAFTON, SYLVANIA, ASSIGNOR TO VANADIUM CORPORATION OF AMERICA, OF BRIDGEVILLE, PENNSYLVANIA, A CORPORATION or DELAWARE.

1i? Drawin g.

' This invention. relates to a composition of alloycontainingvanadium as the major con-.

- usually in the form of ferro-vanadium, 1s

added to'the molten steel after it has been tapped into the ladle. If the vanadium were added to the .steel bath in such a basic furnace instead of in the ladle there would be considerable loss of vanadium, owing tothe oxidizing conditions existing in the furnace.

nace process vanadium is added in the furnace, although part of the vanadium, especially material in finely divided state, isgenerally added in the ladle. It is well-known in steel making practice that the less the total amount of cold material added in the ladle the better and more uniform are the ingots obtained from pouring such steel. The cold material introduced into the ladle absorbs heat in the process of melting and dissolving in the molten bath and consequently reduces the ladle temperature, thus creating the danger of pouring the steelinto the molds at a lower temperature than that requisite for the production of sound ingots.

Also, if the steel tapped into the ladle is not completely deoxidized, the oxides. present therein will effectually burn up some of the vanadium content of the ferro-Vanadium added. To offset, this deficiency, the steel is deoxidized prior to-addition of ferro-vanadium by means of silicon metal or alloys, or aluminum, or both. By the process of myinvent'ion, I propose to incorporate the deoxidizing agents, like aluminumand silicon, into the body of the vanadium alloy, whereby the deoxidation procedure will proceed simultaneously with the alloying of, the vanadium into the steel. By combining the silicon and aluminum with the vanadium in the alloy, very much less material is added into the ladle, inasmuch as the cold iron which would be added in combination with theyanadium and the silicon separately, as ferro-vanadium and ferro-silicon; would be very much greater'than the iron present in the composition of my invention. Besides the decrement of temperature produced by the addition of inert cold iron, the disadvantage was always pres- In the acid open" hearth or the electric furent that unnecessary percentages of other vANAn-Iu -ALUMIiWM-sILIooN ALLOY. I

Applicatien filed February 2, 1928. Serial No. 251,457.

impurities, such as sulphur and phosphorus, were introduced into the molten steel, such impurities being proportionate to the amount of cold iron present and beingderived from the scrap iron used in the manufacture of the separate ferro alloys. If, therefore, twp or' three separate alloys were added, each with the same percentages of objectionable impurities as in the alloy of my invention, it is easy to see that the impurities in the steel will accumulatetotwo or threefold extent. It is also well-known that ferro alloys containing high percentages of silicon and aluminum show a very much less carbon content and' prevent the formation of carbides than if this silicon and aluminum content were absent. A vanadium alloy thereforp containing percentages of aluminum and silicon incorporated in the alloy will carry correspondingly less carbides.

Moreover,'the vanadium content of the alloy ,will be protected against lossby oxidation by the aluminum and silicon present, since the aluminum and silicon are more readily oxidizable than the vanadium.

A Vanadium alloy containing aluminum and silicon can be produced with practicably negligible quantities of iron, so that such 5 an alloy can be utilized for introducing vanadium into non-ferrous metals such as the various aluminum alloys and bronzes. It can also be used in other non-ferrous metals where the presence of iron would be detrimental but that of'silicon or aluminum would not be objectionable.

I obviate the deficiencies enumerated above by producing an alloy containing Vanadium from 40% to preferably from 70% to -90%, together with aluminum from 3% to 15%, and silicon from 5% to 30%, the carbon content of the alloy being negligible, approximately under 50%. The vanadium, aluminum, and silicon contents of the alloycan be varied tosuit the particular specifications of the finished steel to which these alloys have to be added. As examples of typical com-. positions I give the following:

( 1) Vanadium, approximately 40%.

Aluminum, approximately 8%. Silicon, approximately 16%.

Iron, approximately 36%.

(2) Vanadium, approximately 62 Aluminum, approximately 12 Silicon, approximately 25%. Iron, negligible.

(3) Vanadium, approximately 82%.

Aluminum, approximately 6%. Silicon, approximately 12%.

Iron, negligible. (4) Vanadium, approximately 88%.

Aluminum, approximately 4%. Silicon, approximately 8%. Iron, negligible. An alloy containing the high percentages of vanadium, together with the'silicon and aluminum contents, and low in iron content, together with'absence of ca'rbides, is Very readily soluble in molten steel, much more so than the alloys containing low percentages of vanadium and of such other characteris ties as are found on the market today. Further, since'such alloys have the deoxidizing reagents combined in them, they will produce a cleansing of the steel at the moment of its alloying with vanadium, so that the diffusion of the alloying element in such steel will be more complete, producing more homogeneous ingots. Also,there will be an assurance of the vanadium" not being utilized forthe purpose of combining with theoxides present in the steel and thus being lost in the slag, but will effectually and completely enter into the steel, the removal of the dissolved oxides being accomplished by the aluminum and the silicon. Further, since the aluminum content in these alloys is always accompanied'by a silicon content, the product of oxidation will not be an infusible alumina, which, as is well known, remains disseminated in the steel upon its solidification, but will be afusible low melting aluminum silicate which will rise through the molten steel and be eliminated.

The alloy of my invention, containin approximately from 40% to 90% vana ium, from 3% to 15% aluminum, and from 5% to 30% silicon, with less than 50% carbon,

can be produced in the electric furnace by v the use of a suitable reducing agent, such as silicon. However, I prefer to obtain the reduction of the'vanadium content from avery high grade of' vanadium pentoxide by means of aluminum as thereducing agent,- according to the'well-known process of aluminotherimc reduction. The advantage of the alumino-thermic reduction is the facility of obtaining these alloys with practicallyno carbon contamination, which is more diflicult to achievein an electric furnace reduction.

While I have described my alloy in its preferred composition, it is to be understood that-the invention is notso limited but may be otherwise embodied within the scope of the following claims.

I claim:

' 1. A vanadium alloy containing about to 90% vanadium, about 3% to .15-%'igaluminum, and about 5% to 30% silicon, the remainder being principally iron.

2. A vanadium alloy contammg about 40% to 90% vanadium, about 3% ,to 15% aluminum, and about 5% to 30% silicomand containing less than .5% carbon, the remainder principally iron.

3. A. vanadium alloy substantially free silicon, thereby deoxidizing the bath by means of the aluminum and silicon simultaneoiisly with theprocess of alloying the vanadium with the bath metal, and forming an easily fusible aluminum silicate slag.

6. The process of making a vanadium containing steel, which comprises adding to a bath of the moltensteel a vanadium alloy containing aluminum and silicon as deoxidiz ing agents, whereby the steel is deoxidized simultaneously with the addition of the alloying vanadium, and a low melting point aluminum silicate slag is formed. 4

7. An alloy substantially free from iron and containing vanadium, aluminum and silicon as essential elements, the percentage of vanadium being greater than the aluminum or silicon and containing less than 50% carbon.

8. An alloy containing vanadium, aluminum and silicon as essential elements; and together constituting thegreater part of the alloy, the vanadium being greater in amount than either the aluminum or the silicon, the remainder of the alloy being principally iron.

9. An alloy containing vanadium as its major constituent together with smaller but effective amounts of both aluminum and silicon; I

10. An alloyYcontaining vanadium as its major constituent together with smaller but effective amounts of both aluminum and siliconfand containing less than .5%' carbon.

In testimony whereof I have hereunto set my hand. i

,BYRAMJI n. SAKLATWALLA.