US1056125A - Method of treating metals. - Google Patents

Description

pnrrnn srarns PATENT ent ies.

AUGUSTE ROSSI AND WILLIAM F. MEREDITH, OF NIAGARA FALLS, -NEW YORK, ASSIGNORS TO THE TITANIUM ALLOY MANUFACTURING COMPANY, OF NE-W YORK,

N. Y.,'A CORPORATION or MAINE.

Mii'rnon or TREATING METALS.

No Drawing.

Specification of Letters Patent.

Application filed April 17, 1812.

etc, or furthermore by doing this and retaining also in the product some of such agent, whereby desirable characteristics are imparted to the metals so treated.

The objects of our invention comprise the accomplishment of such improvements of the metal better, and more economically, than heretofore, with, if desired, smaller than previously aggregate additions of the purifying agent suitably prepared for the purpose more rapidly and economically than hitherto.

W e attain these objects by the procedures hereinafter described.

It is now established, as evidenced by, the magnitude of actual 1ndustr1al operations,

that free titanium in its elemental, metallic form is exceptionally efficacious to purify and improve metals as aforesaid, titanium when thus free possessing remarkable avidity for the said impurities with Which it combines chemically in the molten metal treated to. form compounds including slags which promptly rise to the surface of the bath whereby the underlying molten;

metal is etliciently cleansed and the final product rendered pure and free from blow holes and other causes of weakness, or furthermore improved by retention therein also of some titanium. States Letters Patent heretofore granted to Auguste J. Rossi also disclose such efficacy of titanium for the purposes mentioned. lt has however been hitherto, naturally, supposed as evidenced by said patents, that such purification by titanium could be successfully accomplished only by additions to the metals treated while molten of an alloy or compound containing titanium in its said The numerous United 1 elemental or metallicstate. The present industrial practice of such purification on extended scales has apparently proceeded exclusively on this theory, the methods pract-ised in producing such alloys, for instance those of iron and titanium as evidencedfor example by said Rossis Patent No. 609,466, dated August 23, 1898 involving procedures carefully guarded to secure final products devoid, as far as possible of chemical compounds of titanium with other elements, and, particularly, it has not, prior vto our present invention, been known or suggested, so far as we are aware, that compounds of titanium with carbon, z. e. carbid of titanium could, as additions to molten metal, operate successfully, or at all, to accomplish its desired purification. We are now however satisfied that this is an error, and

provided it be, as per our method, very'inerated in very minute sub-divisions with other metal, is, if the compound so constituted be added for purification to-molten metal, ultimately as efiicacious, or more so, than metallic titanium and at considerably less cost to the manufacturer. 'Thisnovel compound, so containing the carbid of titanium, as substitute for metallic titanium, possesses,we have found, characteristics rendering it superior, for industrial uses and purposes, to said alloys of elemental titaniumlwith other metals, as for instance the ferrotitanium product of the aforesaid Letters Patent, such superiorities comprising per the method hereinafter described, and also its comparative stability and capacity to delay momentarily liberation of the me tallic titanium, thus enabling less of latter to produce more complete purification OW- ing to its more complete permeation and distribution throughout the bath by disintegration of thecarbid therein before actual purification by liberated metallic titanium begins. I

l will be understood that, prior to our l present invent-ion, the practised methods of producing alloys of titanium by carbon re- 1 duction, as for example per the process described in said Letters Patent No. 609,466, involved application of temperature, 2'. 6. energy, to the charge, sufficiently great to that, on the contrary,'carbid of titanium,

timately mixed and homogeneously conglom its comparatively economical production as insur'e presence, in the final product, of the most possible of metallic titanium; also the addition of substantiallyno more carbon.

to insure not only the reduction of the oxids but also the prevention of carbids in the final product. This procedure has resulted in two considerable items of expense, which our method saves tothe manufacturer, viz: the expense of maintaining the temperature sufiiciently high and long to attain the desired metallic titanium result, and also the expensive drafts meanwhile made upon the constituents of the carbon electrodes employed and also upon the graphitic walls of the furnace because of the stinting' of carbon added to insure the aforesaid hitherto re uired constitution of the purifying alloy.

ur carbid-containing compounds required for practise of our present invention may be produced as follows z-In a furnace capable of developing and maintaining the required temperatures, as for example-preferably .an electric furnace of ordinary type and construction, such'for instance as shown and described in U. S. Letters Patent to Auguste J. Rossi, No. 802,941, dated October 24, 1905, or No. 822,305, dated June 5, 1906, 'is charged, in such proportions as may be desired, metal, for example iron, also titanium oxid and also carbon, the latter preferably in such proportions as not only to satisfy 'the affinity therefor of the oxygen of said oxid, but also enough to satisfy the aflinity therefor of the therefrom liberated titanium, and also enough carbon besides to impart to the resulting product such uncombined carbon content as may be desired, and this with as little expense as possible to the carbon ofthe electrodes, and the graphite linings of the hearth or crucible.

It will be understood that instead of the metal, or iron, mentioned, oxids thereof might be charged,'care being, in that case, taken to regulate the proportion of carbon so as to insure their reduction also. The temperature of the charge is then raised, as by turning. on the current, no higher than sufiicient to insure reduction of the oxid of titanium. It will be understood that the application of such temperature will result in the formation of a bath of the molten introduced in elemental or in oxid f provide d in the later case sufiicient carbon be added. The said temperature is then maintained only sufiiciently long and high to insure, as thoroughly as possible, not only the said reduction of oxids, but also formation, throughout the bath, of the most possible of carbid of titanium. When this stage has been reached, the temperature must be lowered as rapidly as is enconomically possible, lest continuation,- or even slow diminution, thereof result in robbing the carbid-of its carbon, as by latters pass ing into the graphitic state, or making new combinations as with oxids present. The re quired lowering of the temperature thus speedily may be accomplished by tapping the charge promptly as soon as it has reached the stage mentioned, and casting the molten product sufliciently distributed in graphite, or other heat conductive, receptacles.

It will be understood that our compounds of titanium carbid with other metals than iron are producible by the method above I specifically described, the procedure in each case being substantially the same except that such other desired metal or its oxid is substituted for the iron. carbid of titanium with copper, tin, lead,

Thus compounds of zinc, manganese, antimony, etc., may be produced for use in the purification of such metals, or also their otherimprovement as I ,ture with the metal, whereby such carbid of titanium has been, for the first time in our experience, rendered available for use in successfully purifying other- 'metals;-mechanical or other unions of metal with there from separately produced carbids being, as we believe, industrially useless for such pur poses. I

To carry out our present invention we add to a bath of t-o-be-purified molten metal one of our said compounds consisting of titanium carbid mixed with, preferably, such metal. tion of steel, we add thereto, p ferably while in the teeming ladle, a proportion of the said compound consisting principally of iron having therewith intermixed as aforesaid carbid of titanium. This compound is Taking for examplegpurifica result.

incense preferably, preliminarily, more or less comminuted, and is preferably added while the metal to be purified is being poured into the ladle, or it may be introduced while the metal is in the converter, hearth, or crucible, or even in the molds. After such addition an interval should be accorded sutiicient to enable the compound to dissolve in, and thus thoroughly permeate, the bath, to enable the carbon of the carbid to quit its titanium and to enable the thus liberated metallic titanium to accomplish its reactions with undesired elements and compounds, and the resulting new compounds to rise to the surface as slags, etc. Such interval amounts usually to not less than three minutes,

though the time required will. of course,

vary somewhat in each case according to its special conditions, and can readily be determined by those skilled in the art by usual observations and tests. \Ve find that, in usual practice, the best results are attained most economically by additions of said compound, the titanium carbid content of which is from 10 per cent. to 20 per cent. by weight of the mass, but such compounds containing as low as 3 per cent. of said can bid may be profitably employed, and also as high as 80 per cent. It will be understood that a low content of the carbid may prove undesirable owing to the proportionally greater bulk of the compound required for purifying. On the other hand it seems inadvisable to exceed 80 per cent. of carbid in the compound because of inversely proportional influence of the therewith associated constituent metal-of the compound when the latter is added as aforesaid to a bath of molten metal. It will be understood that if purification only is desired, the amount of our said compound added will be proportioned according to its titanium content, so as to supply the metal treated only about so much metallic titanium as is required to satisfy the chemical affinities therefor of all the undesired elements and compounds, including slags. present, and produce a final purified product containing substantially no, or traces only of, titanium. Those skilled in the art will readily understand how to thus proportion the compound to the charge as by preliminary analysis of the compound and of the metal to be purified and therefrom calculating the amount of compound to be added, or by analysis of the final products and varying the amount of compound added to the next charge so as to more nearly attain thereby the desired final In some instances, in which it is desired to not only thus purify the metal treated but also to impart thereto desired qualities by retention of substantial amounts of titanium in the final product. the amount of our new compound added to the bath will be increased correspondingly, and thus if desired even alloys with titanium of the metal treated produced.

Our novel method of treating metals by our said production, and thereafter addition thereto while molten, of compounds consisting essentially of metal containing therewith intimately commingled and homogeneously conglomerated carbid of titanium appears more useful than the previously practised production of alloys of titanium with metal and addition of such alloys to molten metal treated, in that our said novel com- .pound is easier and cheaper to produce, and

insures at less expenditure of titanium the required amount in the bath, whether for purifying or other purposes, all of which is particularly important in view of the present magnitude of metal purifying operations being practised by aid of metallic titanium.

lVe are satisfied that additions of isolated carbid of titanium to baths of molten metal must prove ineffective to purify them, owing not only to the magnitude of the sub-divisions of such carbid, however finely pulverized by any economically practicable me chanical means, but also to the comparative indissolubility, in the bath, of carbid thus added by itself alone. \Ve have found, however, that the carbid, if added in association with'other metal, and in that condition of much smaller sub-division and homogeneous conglomeration with such metal resulting from our method of production, not only dissolves freely, rapidly,. -and homogeneously, throughout the bath of metal treated. thus permeating it thoroughly,but also that its. content of'combined carbon soon thereafter. owing to the temperature and other conditions, separates from its content of titanium, thus releasing within the metal treated, and \when and where most needed, a multitude of comparatively homogeneously distributed very minute particles of free metallic titanium, which then combine. with the-,undesired elements and componds present to form new compounds which. as is now well understood, accomplishes the desired purification.

It will be observed that the addition of the titanic purifier in the form 'of its carbid thus serves, in a measure, as it were, to postpone the action of the titanium as a purifier until better opportunity accorded for its extended and intimate 'co-mixture ing only a few minutes, we regard as more than counterbalanced by the greater opportunity for more evenly distributed action and purification accorded by the carbid character in which the purifier is introduced as above explained, the result including a saving in the total amount ofmetallic titanium otherwise required to produce'the desired final result.

When metals other than. steel or iron are to'be purified, or treated, by adding our said carbid-containing compounds, such additions are made, in the manner above described, to the molten baths of such other metals. It will be observed however that if a final product is desired containing no other than the treated metal and titanium, or traces of latter, the compound added should comprise as its elementary metal constituent metal of the same kind as that treated. Thus for example should it be desired to purify, or treat, molten copper, our compound added thereto should consist essentially of copper and therewith intermixed as aforesaid particles of titanium carbid.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is the followin ,.viz:-

1. The method of purifylng metal which comprises adding thereto while molten a .compound comprising metal and therewith mutually cohesive, and conglomerated, particles of carbid of titanium.

2. The method of purifying metal which comprises adding thereto while molten a compound comprising similar metal therewith mutually cohesive, and 'conglomerated, particles of carbid of titanium.

3. The method of purifying steel which comprises adding thereto while molten a compound comprising iron and therewith mutually cohesive. and conglomerated, particles of carbid of titanium.

4. The method of cleansing metal from.

undesired elements and compounds includmg -slags which comprises adding to such metal while molten a compound consisting.

predominantly of metal having therewith mutually cohesive, and conglomerated, carbid of titanium.

5. The method of cleansing steel from undesired elements and compounds including sla'gs which comprises adding to said steel while molten a compound consisting predominantly of iron having therewith mutually cohesive, and conglomerated, carbid of titanium.

'6. The method of cleansing metal from undesired elements and compounds includallowing the resulting bathfl-to stand until comprises therein contained compounds of titanium have risen to the surface thereof.

7. The method of cleansing steel from undesired elements and compounds including slags, which comprises adding to said steel while molten, carbid of titanium co-.

less than 5 per cent. and not more than 80 per cent. of carbid of titanium.

9. The method of purifying steel which comprises adding thereto while molten iron containing therewith intimately mixednot less than 5 per cent. and not more than 80 per cent. of carbid of titanium.

10. The method of treating metal which comprises adding thereto while molten metal containing therewith intimately mixed particles of carbid of titanium produced by carbon reduction of oxid of titanium while in contact with a molten bath of said last mentioned metal.

11. The method of treating ferro metal which comprises adding thereto while molten a ferro metal containing therewith intimately mixed particles of carbid of titanium produced by carbon reduction of oxid of titanium while in contact with a molten bath of said last mentioned ferro metal.

12. The method of treating metal which adding thereto while molten metal containing therewith intimately mixed carbid of titanium in form and quantity adequate to supply to said first .mentioned metal enough metallic titanium to chemically combine with therein undesired elements and compounds including slags, and allowing the resulting bath to stand until therein contained compounds of ti-' tanium have riven to the surface thereof;

13. The method of treatingferro metal which comprises adding thereto while lbs molten aferro metal containing therewith of titanium have risen to the surface thereof.

' .AUGU STE J. ROSSI.

WILLIAMF. MEREDITH.

Witnesses:

WALTER D; EoMoNns, Prrimr C. PECK.