US1125164A - Copper and process of producing the same. - Google Patents

Description

W. M. PAGE & W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLIOATION FILED APR.28, 1910. RENEWED JUNE 18, 1914.

1,125,164,. Patented Jan.19,1915.

5 SHEETS-SHEET 1.

3110c 1 1 fez-S W. M. PAGE &: W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLICATION FILED APILZB, 1910. RENEWED JUNE 18, 1914.

Patented Jan. 19, 1915.

5 SHEETS-$113111 2.

Q-Qitm coma Patented Jan. 19, 1915.

5 SHEETS-SHEET 3.

Q QL 11400000 W. M. PAGE &. W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLICATION FILED APR. 28. 1910. RENEWED JUNE 18.1914. 1

Patented Jan. 19, 1915.

' 5 SHBETSSHEET 4.

ZV/rZ Zkss/W wwmeooeo W. M. PAGE & W. TASSIN. COPPER AND PROCESS OF PRODUCING THE SAME. APPLICATION FILED APR. 28, 1910. RENEWED JUNE 18, 1914.

1,125,164, Patented Jan.19, 1915.

5 SHEETS-SHEET F WILLIAM MARsnALn men, or PHILADELPHIA, ND .wm'r .rAs'sIN, or cnnsrnn, PENNSYLVANIA, ASSIGNOBS cro'rrm DUPLEX MET L-s COMPANY, or. NEW YORK,

N. x, A coItPoaAmIoN or NEW YORK.

COPPER AND rnocEss or PRODUCING THE sAM Specification of Letters Yatent.

Patented Jan. 19, 1915.,

Application filed April 25, 1910, Serial no. 558,093. Renewed June 18, 1914. Serial No. 845,976.

. per-clad metals and processes of producing the samefand it comprises a new form crystalline, fine textured copper, such copper being suhstantiallyfree ofogrygen and oiiids, carbon 'iron and exhibiting upon polishing and etching a section of a casting a relatively coarse and flaky or platy macrostructure, free of visible lines of demarca tion" or cleavage between the component plates or flakes, such platesor flakes under the microscope appearing integrally umted and each such plate: or flake showmgvery small isometric crystals regularly arranged and having the same lines of orientation in any one plate' though haying drtl'erent l nes in adjacent plates or'flakes; and 1t also comprises'"clad metal art cles proyi de d W1th a layer of copper hayingthe descrlhed properties an 'a'ppeatancei and further comprises a Inetliodotproducmg such copper and of attaching such cop' er to other metals, saidmetho'd comprising the steps of freeing copper of oxygen and oxids solution or metallic iron or steel therein and a subsequent limited oxidation to r eye the cxce'ss'o'f such iron where an e'xcess'is used;

all as more fully 'hereinaftersetforth as claimed. I

T e rd ary go ppe of h ma kets thou yery frequently nearly pure and containing hut'a limited'absolute impurities is Yery inu'ch afiected, as' j'to properties by .the limited amounts of such 1mpurities which do exist. contains both cuprous and cupr o oxids the forme'nbe ng P ly, a least o a la ge e'x ent'ymtm form of a solid so utio'n. Cluprous oxid is soluble in molten copper audit probably does not separate to anyritent 'iuso lidifica tion of. such copper." The 'cupricioXid on the other hand'exlst's, least partially, in

a discrete form; as particles separate from the copper particles. On microscopical. examination of a polished and etched surface, it shows a more or less granular structure with, usually, more or less cupric oxid between and bounding the grains and there are clearly evident lines of demarcation be-" tween such grains. There are also minute depressions or pitting. Ingot copper con.- tains oxygen and othergases; partly in the form of a solidified solution, probably, and partly also in theform of bubbles or imprisoned bodies, causing the Well known sponginess of cast copper. There are also minute quantities of other metals; partly present, probably, as oxids and partly, probably, in the metallic form. All these impurities affect both of two of the important properties of copper; its strength and its conductivity. In so far as cupric oxid is present in the copper as such it'must of course form a weakening constituent $111.08 1t herever itis present-and since it is not a good conductor it must also reduce the conductivity by lessening the conducting section Wherever it occurs. The cuprous oxid also reduces both strength and conductivity and the 'sponginess likewise reduces both prop.- erties. The dissolved gases and oxids and foreign metals also reduce the conductivity; and, probably, in most cases, the strength also. These contaminations ofcommercial ingot copper are dueto and accuratelyrepresent the conditions under which the usual preparation, purification and castingv of copper are performed.

In the'ordinary operation, the copper is melted in some type of flame heated furnace, the flame being run oxidizing for the sake of a quick development of heat though the copper is melted and cast at'as low a tem-.

- prerents metallic union of copper to copper ordinarily poled with a wooden pole. WhlOll 1 n charring evolves reducing gases 7 which are presumed to remove the absorbed oxygen and to reduce contained oxids, the poling operation being carried on till a removed sample shows the desired fracture" and-texture; the ordinary texture of commerclal ingot copper. The reducing action is never carried on to the limit or indeed very far, overpoled copper not-being considered as good in quality as that which has,

been poled to a less degree. The reason for this is not definitely known although it is being in a succession of waves.

assumed that a continuation of the poling long enough to produce overpoled copper results either in the reduction of the oxids of foreign and harmful metals or in a solution of carbon. Since the oxids of most of the metals injurious to copper are as easily reduced as copper oxid, or even more easily, the former explanation has not gained full credence. Another explanation is that the presence of a certain amount of cuprous oxid in copper is desirable as giving the copper better properties. At all events in practice the poling is never continued long enough to remove all contained oxygen and oxids. After the poling, the copper is cast into ingots. As stated, at the time of casting the molten copper is usually rather low in temperature, not being ordinarily much more than hot enough to flow, and not so freely fluid as at higher temperatures. And from this low-temperature molten copper the oxids and other impurities do not rise freely by floatation; this being particularly the case with the black or cupric oxid which is comparatively high in specific gravity. In casting the copper, further oxid is formed since hot copper in contact with air instantly becomes covered with a layer of oxid, so that in passing through the air, the surface of the molten stream becomes oxidized. And as the molten copper is at a comparatively low temperature, the first portions entering the mold chill enough to set quickly and retain the oxid in the mass as entangled skins and films. In a 4-inch wire bar ingot, for example, a study of sections under the microscope will show that it may be considered, broadly speaking, as composed of three parts. In the bottom layer, composed of the copper first entering into and splashing in the mold, the copper may be regarded as All these waves, because of the chilling action of the mold, set almost immediately and the film coating of oxid which they carry remains entangled and held in the solidified copper. As the copper rises into the second third of the mold, this splashing or Wave action ceases and the incoming stream of hotter meme-e molten metal forces its way downwardly through the top layer, .-al'lowing the oxid to rise to a certain extent and float at the top. This floating oxid is carried to the top of the mold and since the top layer in the mold sets very rapidly on finishing the casting, the

. top layer of metal always carries muchentangled oxid. v

In the center of a bar of copper produced in the described manner there is usually a limited portion of copper relatively free from oxid. In a microscopic examination of polished and etched copper from such an ingot, the surface appears-to be composed of small grains and between these grains often occur black lines of copper oxid. In extending such a bar to 'form wire, the oxid of copper separating the crystals forms lines of weakness and of insulation, reducing both;

the strength and the conductivity. Obviously, wherever in the interior of the mass copper oxid spaces copper" from copper, not only is the strength locally reduced but the conductivity is locally lessened. The exam ination of the copper either in the bar or in the wire, as stated, also shows pitting, 'due to the liberation of absorbed gas in the solidificationpf the ingot. In good ingot copper the amount of the pitting and of the oxid is always small and, as stated, different portions of the same ingot or of the wire drawn from the ingot will show quite different amounts of both, but both are usually found and in some particularly bad specimens of ingot copper, the copper under the microscope may be said to look like a conglomerate or concrete consisting of a copper aggregate in a cupric oxid matrix.

In the present invention, molten copper I metal is maintained during the operation at 1 a relatively higher temperature than is usual 1t being found that, contrary to the usual impression, under the hereinafter described conditions, high temperature and a long-continued heating are not detrimental. This is, very probably, because of the peculiar conditions. Copper at this high temperature is freely fluid, allowing non-metal- 11c 1mpurities to rise easily and completely therethrough. Having the copper in this highly heated, freely fluid condition, and advantageously the temperature may be above the melting point of steel, metallic iron or steel is added in such a manner as to distribute it through the mass. In the presence of this dissolved and disseminated iron, all the oxygen present, whether merely dissolved or in combination with the copper, at once combines-with the iron, forming oxids of iron, which risethrough the freely fluidv copper and float upon its surface. The

mamas amount of iron or steel used may 'be merely that required to remove the oxygen, or it.

may be in some excess, this excess being later removed by the hereinafter described method. The iron may be added as copper-clad steel scrap, or as ironor steel. The

iron or steel need not be clean and maybe contains ferrous oxid, a reducing body.:

Such of the scale as does not take part in the reaction rises through the copper harmlessly. The carbon, silicon, manganese, etc., in the iron or steel also take part in the re ducingaction to an extent proportional to their amount; the carbon forming gaseous oxids which produce an ebullition and exercise a stirring action. Practically all the bodies present in steel, like iron, have a reducing action upon the oxids of copper and are able to remove dissolved oxygen. Ad-

vantageously, the treatment with the. iron orsteel-can be performed by rabbling, stirring or agitating with steel or iron bars, the molten copper being in the form of a relatively deep bath. With copper at a temperature above the melting point of steel, the particles of molten iron tend to rise through it and produce an intimate mixture and thorough reduction. After this treatment, the copper is free of oxygen and oxids and of all foreign materials save for the presence of iron where an excess has been used. The iron oxid and other oxids produced in the reaction rise to the surface of the fluid copper. It is next necessary to remove any excess of dissolved iron. For this purpose, the

cop er may be melted in a flame heated .furnace with the flame of the furnace sweeping I close to its surface, such copper being kept covered with floating carbon, such as charcoal or coke, or both. With the flame sweeping close to the surface of the copper, the usual air layer between the flame and the metal is practically absent and no opportunity is afforded for free oxidation. I In the presence-of the carbon floating upon the copper, such oxygen as is present and the carbon dioxid of the flame both tend to form carbon monoxid. Practically under the described conditions the surface of the popper is blanketed by a bath of carbon monoxid and some carbon dioxid. Both these gases are oxidizing to iron, but are not oxidizing to copper. And while carbon monoxid is soluble in molten copper under some conditions no material solution appears to occur here. By treating the iron-containing copgen, oxids, iron and-dissolved gas and displaying new and advantageous characteristics. Suchcopper upon casting gives a homogeneous" ingot, showing no s'ponginess due to the development of gas in solidification, andshowing no lines of oxid when a cast specimen is polished and etched. It is,

furthermore, free of dissolved cuprous oxid.

Cast copper of this character when polished and etched in "fact shows a new and distinctive surface appearance. In lieu of showing a small grained'texture with clearly marked ,lines of demarcation between the several" grains, and frequently, lines of black oxid as well, it shows upon polishing and etching comparatively coarse or large plates or flakes plainly visible to the naked eye without noticeable lines of demarcation, of cleave age or of separation between adjacent flakes or plates. 'Each such flake in turn shows a microscopic substructure composed of orientated isometric crystals.v The lines of orientation inany one flake or plate are parallel and like in direction, while the lines in adjacent flakes or plates are not so parallel.

Any suitable type of furnace or melting apparatus may be used in performing the described process, but some type of oscillating or tilting furnace may be advantage-' excess of iron. A tilting furnaceprovided with a deep well for the reception of molten copper during the first stage and a large relatively shallow reverberatory hearth for use during the second stage is particularly suitable. The deep well may form a lateral pocket at the side of a tilting furnace of substantially cylindrical cross section.

The copper after the purification may be cast at once in any of the ordinary forms of ingot mold. At thedescribed temperature it is .thinly fluid and oxid formed during the pouring operation-rises in the copper in the mold and does not contaminate the body of the copper. If desired, however, the casting may be done under special circumstances precluding oxidation during the pouring, as when the copper is to be allowed to fall in temperature and cast at the usual comparatively low temperature. In such event, it may be cast directly into a mold filled with producer gas or other inert gas. Or the mold may contain a body of hot molten slag or flux. -The use of a mold containing a protective substance, such as a gas or slag, may of course be resorted to when casting the copper at a high temperature. There is no reason with the present type of copper why casting should not be at a high temperature since a high temperature per 'se is not injurious in the present operation.

the

The described type of copper is advantageously employed for forming the main body of the "coating of copper clad steel. For copper clad steel it is desirable that the coating be as impervious as possible and for most purposes that it have a high conductivity for heat and electricity. For Wire and sheets it is also desirable that the clad metal have a high tensile strength. The described type of copper being free of pits or sponginess, allows the production of comparatively thin films upon steel without risk of porosity which will permit corrosive agents to penetrate through to the underlying metal while its conductivity and strength make itvery suitable for thicker clad articles. Tn producing clad metals with this type of copper, the production of the copper can be advantageously combined with that of the clad metal itself. For this purpose the necessary treatment with iron may be given while treating a billet or other body of ferrous metal which is to be coated. For instance, a body of copper, (which may be fairly impure) may be treated by dipping therein a billet of steel which is to be susequently coated. The steel in passing through the mass will afiord the necessary iron to reduce the oxids and combine with the oxygen present, and will also become covered with a thin, welded-on, cohering coating of copper which will remain on it when withdrawn. Such withdrawal is best into a neutral atmosphere, such as producer gas, to shield the hot clinging copper against oxidation. Even with producer gas it is best to remove any contained oxygen or carbon dioxid, as by a previous treatment of the gas with suitable chemicals such as an alkaline solution of pyrogallic acid.

Since the oxidation of carbon is preferential over the oxidation of iron, in this dipping operation under the described conditions using copper containing oxygen the superficial carbon in the steel is burnt 0r oxidized out, leaving a layer of carbonless iron with which the copper unites freely to form the described coating. Certain alloys are produced also by the union of the iron and the copper, and the alloys produced under these circumstances are materials of desirable properties, having a good degree of tensile strength so that their presence is advantageous in the finished article. Genera'lly next the steel there is a layer of alloy high in iron and low in copper while beyond it exteriorly is a layer of alloy rich in copper and low in iron.

In making the clad metal, and particularly where the copper is already fairly pure, not containing much dissolved and combined oxygen, and where the steel contains considerable carbon, it is often advantageous to add some oxygen in the form of iron oxid to reinforce the oxidation of the mas er carbon. For this purpose, the billet may be preliminarily given a cleansing, as by sandblasting and pickling to remove coarse scale,

sand, etc. The billet which may have been part from the decarbonized metal beneath.

T he heat of molten copper is sufiiciently for this purpose. This pure iron is advantageous for the present purposes because it dissolves more freely in copper than do the ferrous carbids found in steel, to produce the purifying iron in solution, and it forms the desirable linking alloys and promotes the production of the weld-union. In the purification of the copper, the ferrous oxid of the magnetic oxid plays some part; partly, probably, by reduction.

After the reaction is complete which is shown usually by the cessation of ebullition due to the evolution of carbon oxids, the billet may be withdrawn, and is found covered as stated with a clinging cohering welded-on coating of copper. Against this copper filmed surface may now be cast a further amount of copper to produce a coating of the desired thickness. While copper may be attached to the filmed surface in other manners, it is desirable that it be applied in the molten state and that it be, for the purposes of the present invention, the purified copper previously described.

The bath of copper from. which. the billet has been withdrawn may now contain an excess of dissolved iron. In such event it is treated by a nearly impinging flame in the presence of carbon in the manner described to remove this excess of iron, the flame,

being so directed as to sweep close to the surface of the molten metal. The purified copper-may now be applied to a previously filmed billet in any convenient manner. Or, if the operation is properly conducted, the amount of iron dissolved from the billet may be merely that necessary to remove the oxids from the copper, leaving the copper substantially pure and ready for forming the coating. This correlation between the amount of iron dissolved and the amount of oxids in the copper may be easily adusted by a little practice and experiment, so that the dipping of the billet and the purification of the copper are simultaneous operations. In operating in this manner,

'. there is, strictly speaking, no excess'of iron dissolved in the copper; there is merely the amount of iron dissolved which is requisite for the purification of the copper bath.

In applying the purified copper to the filmed billet in the manner described it is advantageous to allowthe temperature of the copper to drop somewhat, this being for the reason that the very hot copper might melt ofi thecopper iron alloys on the surface of the billet and become contaminated. By a further adjustment of conditions in the operation .however, this reduction in temperature may also take place simultaneously with the filming and the purification ofthe copper. Where a small amount of very hot copper is contained in a comparatively small dippin vessel and the relatively cooler billet ipped therein, the first action is that of heating the surface of the billet to a very high temperature. temperature the solution of the iron, the reduction of the iron oxid, where such is present, and the purification of the copper all go on at'once. As the heat penetrates inward in the billet, the temperature of the surrounding copper drops until it reaches the desired lower temperature, whereupon:

this copper may be directly applied ,to the filmed billet. For some purposes, a convenient method of operation is to run very hot copper intoa relatively small hot dipping pocket or container, dip a billetthereinto until the copper is purified and the surface of the steel covered with welded-on copper, and then follow by dropping around the billet a mold casing adapted to inclose an annular layer of copper ofthe correct thickness,-about the billet, thereafter removing v j billet, casing and contained copper together.

For this purpose, the billet should be provided at itslower end with a cap or disk adapted to make a tight joint with the easing, It is better however to perform the operation in two sta'ges,first, alloy coating the billet in the manner described and then bringing the copper into contact with the alloyed surface.

copper asit'flows in to solidify first on such inner margin and ultimately fill up the space between such solidified copper and the filmed surface. Operating in this manner there is no danger of a permeation of the iron of the .iron-copper alloy on the billet through the whole mass of the coating. Where electrical conductors are to be made this is very desirable for the reason that even a minimal amount of iron runs down the conductivity of the copper inordinately. And with-the very pure, highly conductive, special form of At this structure, the copper when once brought to 1 In doing this it is con-' .venient and desirable to use. a relatively cool copper of the present invention, it isof paratus being alternately used for dipping and for forming the substantial coat. Operating thus, the billets may-be dipped into the copper until enough iron has dissolved therein to remove all impurities, the purified copper then freed of iron in the manner described, allowed to fall in temperature and then used for forming coatings.

While ordinary, ladles or molds may be used in' connection with ordinary copper melting furnaces in performing the described operations, as stated, it is better to use a rocking furnace with a built-on dipping device adapted to allow a to-and-fro flow of molten copper as this gives a better control of conditions and minimizes the chance of contamination of the molten copper during the operation. With such a the described condition may be kept of the proper composition; and it has the further advantage that by proper correlation of relative dimensions and conditions, the described unitary operation of alloying'the billet, purifying the copper and reducingits temperature may easily be carried on. The molten copper from the furnace may, for example, be flowed into the dipping device' at a temperature of, say 1380 (l, which adapts it both for alloying the billet and for purification by iron dissolved off the same, and then by the chillingaction of the billet it may be reduced to, say, 1280L- After the coating operation, the residual copper may be run back" into the furnace and brought back to a high temperature. With a proper correlation between the dimensions of the billet and the amount of copper in the dipping bath, it is easily practicable tobring about a temperature drop of a hundred degrees in the operation itself.

In lieu of using ordinaryiron or steel as the core metal of course any of the commercial alloy steels or ferro metals, such 'as '115' chropie steel, manganese steel, nickel steel, coba t steel, etc., may be employed. Or, 'one of the iron-like metals, such as nickel or cobalt may be employed in lieu of steel or-iron.

ln the accompanying illustration are shownmore or less diagrammatically, certain apparatus useful in the described process, and there are given certain v ews representing the metal, these views belng taken from on inal photomicrographs filed herewith, said views representing said photomr. crographs as nearly as may be withln the limits by the Patent Office requirements for v patent drawings.

' In this showing: Figures 1, 2, 3 and 4 i Ml tion to inch rod; Fig. 11 shows a micro? show views on an enlarged scale of polished and etched masses of ordinary copper of different brands; Fig. 5 shows a similar sec-- tion of anordinary commercial wire bar; Fig. 6 shows a simliar section of copper which has been twelve hours molten in a crucible; Figs. 7, 8 and9 are representations of the microscopic appearance of the new copper and Fig. is a similar view of the same copper after having undergone reducscopic view of the structure of steel and In the apparatus of Figs. 12 to 15, 1 rep-.

resents a metallic casing of any suitable material lined. with refractory material 2 and having a central flame chamber 3. Comvalvedpipes 15 and 16 feeding burner 1T municating with this chamber are ducts 41 set at an angle and communicating with chamber 5 for molten metal. This furnace chamber is arranged to be tilted on a horizontal axis and to facilitate tilting it is provided with bearings 6, and a shoulder 7 provided with lever arm 8 carrying a weight receiving device 9 to aid in counterbalanc ing. At one side opposite the metal duct the furnace chamber is shown provided with port 10 adapted to be closed by swinging door 11. 12 and 13 represent the framework carrying the furnace. Oil pipes 14 (see Fig. 1 1) provides for firing at either or both ends of the flame chamber by means of provided with air or steam injecting means 18. When the apparatus is to be used for coating iron or steel with the new copper, a dipping casing 19 provided with means 20 for introducing. producer gas or other inert atmosphere and hoisting means 21 and 23 may be employed. This casing surrounds billet 22 which may have been sandblasted or otherwise treated and is provided with an end cap 2% adapted to make a tight joint with the bottom of the casing and an inlet 25 provided with sealing means 26. This sealing means may be a ring of asbestos or metal which is adapted. to be ushed aside when the orifice is to be used 'or the introduction of metal. When the apparatus is to be used for mak- \ng ingots of the new copper it may be provided with a pouring lip 27 and suit able ngot molds 28. These in ct molds may, if desired, be provided wit a filling me ian 29 of suitable fluxor slag adapted to be or become molten at the temperature of the cast copper, such as borax, cryolite, silicate of soda, iron slags, a halogen compound, such as salt, etc., or an indifferent atmosphere, such as producer gas, may be blown into the mold from pipe 30 during the pouring operation. This roducer gas will displace the air in the mold and prevent oxidation of the cast copper as it flows in the top of the mold. It will burn in contact with the air but this burning is not injurious to the operation. Ram 31 may be used in loweringand raising the chamber 5.

Tn'the showing of Fig. 1, the metal is an excellent quality of commercial copper, showing but little diflferentiation in texture.

In the showing of Fig. 2, which-is an ordinary grade of commercial copper, the large white areas are grains of copper while the black lines represent layers of oxid therebetween. The showing of Fig. 3 is about the same. As will be observed, both samples are rather bad.

In the showing of 'Fig. 4c, the white and dark areas both represent copper while the black spots are pittings and oxids. And by careful examination it will be noticed that there are lines of separation and demarkation between the crystals of copper and these lines contain more or less oxid of copper.

Fig. 5 represents the microstructure of a sample of ordinary wire bar.

Fig. 6 is copper which has been molten in a crucible for 12 hours but has not been purified and shows a crystallization of copper together with impurities and pitting. It shows one dendritic crystal of copper.

Figs. 7, 8 and 9 show as nearly as possible within the limits of photography, the peculiar optical appearance under the microscope of a section of the new copper. After the new copper is well polished and is etched somewhat it displays to the eye a peculiar flashing appearance as if the sur face were composed of lakes or plates without -visible lines ofdcniarkation between them. This optical appearance while very characteristicand.veryfldistinctive is hard to reproduce. views, this structure is less evident but the On enlargement as in these sets of parallel crystals together form the flake-like areas visible to the naked eye. Tn these views the flakes are resolved into microstructure of parallel isometric crystals regularly arranged. Figs. 8 and 9 show this parallelism very clearly. Fig. 10 shows a microview of the same copper which has been drawn out to inch rod. Tn drawing out the copper, the peculiar structure of the ingot copper is of course changed considerably. Fig. 11 shows a view on the same scale of a clad metal billet, the view being taken across the line of joinder. The upper .troduced.

back into the-purifying position and intro ducing a layer of floating carbon upon the or homogeneous looking area is the copper and .the .lower. is the steel. Inpolishing a sample suchas this, it is difiicult to adopt a method of polishing and etching which will show the peculiar microstructure of both metals. Between the upper copper area and the lower 'steel area is'shown a band or layer of copperiron'alloys. this band will'be seen to have an upper blackish area which is a high copper alloy. Below this are grayish areas of various copper iron alloys and below these again there is a layer of high iron alloy. The copper extends more or less into the edge of the iron area.

In the apparatus shown the copper .may

be melted in the chamber 3 by the oil flames from 17 The furnace may now be tilted and iron introduced in the copper in chamber 5 best by dipping a billet-or ro'd therein. The

copper for this operation is best ata temperature above the melting point of steel. T he steel melting and dissolving in the copper frees it efiectually of oxygen and oxids, while by dipping the relatively lighter steel in the relatively heavier copper the molten particles of steel upon rising flow through thecopper and give a good distribution of iron therein.- By carefully controlling the conditions of the operation, merely the amount of steel may .be introduced which sufiices to remove oxygen and oxids, leaving the copper ure. I Ordinarly an excess is inpon now tilting the furnace surface of the copper, upon heating with the oil flame, this excess of iron burns out,

leaving copperof the composition described. Upon again tilting the furnace the purified copper flows out into chamber 5- when it may be east through 27, into the ingot mold 28. Or the billet 22 may. be dipped in the chamber 5, at once serving to purify the brought to a very high temperature in 3,-

transferred into 5 and the relatively colder billet introduced. The conduction of heat through steel being relatively .slow the surface of the billet acquires the temperature of the copper, suflicient iron dissolves to remove oxygen and oxids, forming floating oxid of iron, and then thetemperature of the purified copper is somewhat reduced. Upon now introducing the billet into the casing in such manner that 24 makes a seal Upon examination at the base of the casing and dropping ca sing and billet together into chamber .5, .the

copper is now cooled down to a castingtemperature and it may be allowed to flow. in through 25, 26-being removed, toform the main body of the coating.

What we claim is:.--

1. The process of purifying copper which comprises treating such copperin .a highly heated molten condition with iron in excess of the amount suflicient to react with oxygen and oxids present and thereafter removing such excess of iron.

2. The process of purifying copper which comprises treating such copper 1n a highly heated molten condition. with iron in excess of the amount sufficient to-react with oxygen and oxids present and thereafter burning out such excess of iron under conditions precluding re-oxidation of the copper.

3. The process of purifying copper which comprises treating such copper in a highly such excess and then producing a solidified body of copper under conditions precluding reabsorption of oxygen.

The process of preparing copper castings which comprises treating copper. in a highly heated molten condition with iron in excess of the amount suflicient to react with oxygen and oxids present, removing such excess and'the n producing a solidified body of the copper in an atmosphere of inert gas.

6. The process of purifying copper which comprises treating highly heated -molten copper by contacting the same with a body of steel until sufficient iron has dissolved to remove oxygen and oxids, removing the body of steel and heating the copper under conditions. permitting a preferential oxidation of the dissolved iron until such iron is. removed.

7.. The process of purifying copper which 8. The process of purifying copper which comprises bringing copper to a highly heated. molten condition in a tilting furnace provided with a dipping pocket, tilting the furnace to flow the coppermto such pocket,

rte

8 Y mama i dipping a steel object into the copper until sufficient iron dissolves to free the copper of oxygen and oxids, returning the copper to the furnace and burning out the dissolved iron.

9. The process of purifying copper which comprises bringing a body of such copper to a temperature in excess of that required to melt steel, dipping in a body of steel until sufiicient iron has dissolved to remove oxy gen and oxids, burning out the excess of iron by preferential oxidation and forming a solidified body of the purified copper.

10. In the purification of copper, the process which comprises stirring molten copper with a steel object until oxygen and oxids are removed, burning out the excess of dissolved iron by preferential oxidation and forming a solidified body of the treated copper under conditions precluding oxidation.

11. In the purification of copper, the process which comprises stirring molten copper at a temperature above the melting point of steel with a steel object until oxygen and oxids are removed, burning out the excess of dissolved iron by preferential oxidation and forming a solidified body of the treated copper under conditions precluding oxidation.

12. In the purification of copper, the process which comprises stirring molten copper with an oxidized steel object until oxygen and oxids are removed, burning out the excess of dissolved iron by preferential oxidation and forming a solidified body of the treated copper under conditions precluding oxidation.

13. In the purification of copper, the process which comprises stirring molten copper at a tempertaure above the melting point of steel with an oxidized steel object until oxygen and oxids are removed, burning out the excess of dissolved iron by preferential oxidation and forming a solidified body of the treated copper under conditions precluding oxidation.

14. As a new article of manufacture, an object comprising a body of copper substan tially free of oxygen, oxids and iron, said body upon polishing and etching exhibiting a relatively coarse platy or flaky microstructure and microscopically examined displaying a crystal structure of regularly arranged isometric crystals having the same orientation within any one flake or plate, the lines of orientation within adjacent flakes or -plates not being the same, but displaying no apparent line of cleavage or demarkation between such adjacent flakes or plates.

15. The process of" purifying copper, which comprises bringing copper to a highly heated molten condition, forming a relatively deep dipping body of said molten copper, dipping a steel object into the body of molten copper thus formed until suliicient iron dissolves to free the copper of oxygen and oxids, and then forming a relatively shallow body of said molten copper and burning out the dissolved iron.

16. The process of purifying copper which comprises bringing copper to a highly heated molten condition, forming a dipping body of said molten copper of considerable depth but relatively smallhorizontal cross section, dipping a steel object into the body of molten copper thus formed until suflicient iron dissolves to free the copper of oxygen and oxids, then forming a relatively shallow body of such molten copper, and burning out the dissolved iron therefrom.

In testimony whereof, we aflix our signatures in the presence of witnesses.

WILLIAM MARSHALL PAGE. A IVIRI 'IASSIN. IVitnesses I M. Wars,

JOHN B. PA'r'roN.

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