US928470A - Mold. - Google Patents

Description

J. P. MONNOT.

MOLD.

APPLICATION HLBDAPB.so,190s.

Patented July 20, 1909.`

tirarse srafrrs JOHN l". MONNOT, Oli KEW YORK, N. Y., ASSIG XOR TO DUPLEX METALS COMPANY, Ol" NEW YORK, N. Y., A CORPORATION OF NEW YORK.

IJIOLD.

Specification of Letters Patent.

Patented July 20, 1909.

Application led April 30, 1908. Serial No. 430,097.

To all irlzom it may concern:

lle iti known that l, JOHN l". Moxxo'r, a citizen ot the United States, residing at New York, in the county ot Kew York and State ot New York, have invented certain new and useful linprovenients in Molds, of which the following is a sieeiiication.

This invention relates to ingot molds; and consi. ts in a built-up ingot mold having a metallic casing and a liner of dense hoinogenized heat conductive refractor)v material in heat-conducting relationship to such casing; all as more fully hereinafter set forth and as claimed.

In a prior patent, No. 853,716, l have described and claimed i niethod'ot' producing clad metals comprising ferrous nietal bodies having integrally, aatogenously and permanently united thereto b v a union ivhich is, or is equivalent to,l a veld union, coatings or' bodies of unlike high-ineltingiwiggr` metals such as copper, silver, gold, etc. lhis niethod rests upon the fact which l have discovered tl at; these unlike non-ferrous metals which ivill torni ne permanent union ivith tei-reus metals when contacted therewith at their comparatively low ordinar7 casting temperatures, vwill e1 the other hand torni such a union il conta :ted therewith at a teniperature much above their` melting point. At this elevated temperature these non-ter` rous metals are in a condition Which I have termedA` for lack ot other naine, a. super niolten condition in which the)Y evince not onlvv a high degree ot' ai'linitv`r chemical or physical, for iron or steel, readily i wetting ity in a Way of Which they are incapable at lovfer temperatures, but also for gases and other materials as ivell as for other metals.

ln the method otl the stated patent, as vvell as in the methods ot sundr5r other specific embodiments tor ivhich l have tiled applications ttor Letters latent, the tact of this in` creased ailinity is utilized and the desired types of union are produced by casting one of the metals, preferably the non-ferrous, in a highly heated condition about or against the other metal, the solid metal also being prel'erabl)v heated though not to the saine degree. For instance, in producing copperclad steel, l Vmay take a steelr billet in aheated condition :unl momentarilycontact its surface, as by dipping, with superniolten 1 copper at a temperature of, say, 2500O F. This contacting results in the t'orination of a clinging hn ot copper tirmlv perinanenthr and autogenousl)Y united to the steel by a union Which is, or is equivalent to, a Xveld union," and against. this coppered surface may novv be east copper, silver, Oold, etc., at a more convenient casting temperature to torni the niain bodv ot the coating. Or

may apply the whole body of coating nieta` inthe superinolten condition to` forni thfe complete clad billet at. one operation. lt iis more particular-l5Y in this latter operation that inv nen' ingot mold is to be employed though it is of course susceptible of use in any other high temperature casting operation. However, taking this single-step eoating operation as typical, it is obvious that the requirements oi. an ingot mold are trg.'- ing. lt. must be ot neutral, refractory inat'erial to prevent contan'iinatioi'i ot the superinoltcn nietal; itl inust have sonic mechanical strength to prevent erosion by the pouring or other manipulation ot the very hot, very fluid superniolteu metal; and it should be readily heat-eonductive since in practice it is eminent y desirable that the copper or other super-molten inetal be not maintained in contact with the iron' in a superniolten state any longer than is neces-sali,7 to torni the union, a matter ot a few seconds, as longer contact would result in pernieation ot the iron billet by copper and contamination of the copper coating with iron. For this reason, after formation ot the union it is desirable that the temperature be at once reduced to a safer degree. In the described operation, this may be in part eltected by having the steel `core at a somewhat lower temperature than the superinolten copper so that though its Surface vvill momentarily acquire the high temperature (conduction of heatin steel being relatively sloiv) yet the heat vvill soon soak inward .troni the Zone oit' contact ofthe tivo metals, reducing this zone to a safer temperature. Partly also the de sirable reduction of temperature in this Zone is usually ell'ected by outward conduction through the niass e'tcopper and the ingot inold and the skin cooling of such mold bv the air. This latter result, however, with the types ot' inolds hithertoin use has notbeen as eliicient as is desirable, and one of the main objects ot the present invention is to devise a mold in which such cooling action can be better developed.

Naturally the supetmolten copper can not well be cast into a. naked steel mold, since it would tend to coherfe to it as well as to the billet to be clad and would also become contaminated with iron, nor can it advantageously be cast imo molds of the usual ret'ractory materials, such as clay and the like, since these are not etliciently heat conductive; neither can they well be chilled suddenly. Steel mcl'ls lined with graphite paste do better but not as well as is desA 'able since if the graphite be used in a pure condition, it is too sot to withstand erosive action of the very fluid metal so that molds require relining after each billet, neither is there any certainty to the exacty size or shape of the compound billet produced while the heat conduction et graphite existing in disc-'rete particles, as results from making a liner ot such paste, not as eiiicient as is desirable; moreover` the ditterent rates ot' expansion ot' the lining and shell tend to produce separation tt the two. gira/pinto with a binder such as tiro clay has better mechanical strength and is more durable in proportion to the amount of binder used; but the heat conduction diminishes more than proportionately to the amount ot such binder.

To secure good lxeat conductivity, the texture of the mold 1' mst be hard and dense with the particles o1' the heat-conducting material in good heat-conducting' contact.,

. which precludes any porosity or any spacing apart of such particles such as is inevitable with a clay bnder.

In another invention for which I have applied for Letters Patent, the application bearing Sr. No. 400,151?) I have devised a way of producing sound castings based upon the maintenance in the ingot mold during the casting operation of a substantial body of fused mineral wiping liquid through which the molten metal Anay be poured, thereby wiping it tree of absorbed and entraincd gases and moisturi and superficial oxid while such wiping liver as it rises above the cast metal also wipes free the mold wall of such absorbed and entrained matters. Since most ot these minerai wiping substances are corrosive of and wi'l tlux earthy materials,

-the ordinary refractory mold linings are not 'hoznogenized carbon in heat conducting re- 3lationslup with such casing and having its own particles similarly in heat conducting' relationship to each other as well as in state of good mechanical union to give th substantial degree of strength necessary to? the described purposes.

I-Iomogenized carbon linings of the cha/rf -acter desired may be produced in a number of ways. Such dense varieties ot carbon as gas carbon, o'raphiteJ etc., may be powdered and given thd'esiiifcd shape, either thatot/ the mold liner or a segment thereof, such as a slab adapted to assemble with other slabs, with the aid a carbonaceous binder sueltas.-.mousseline imfC-ira; l i,arred The cohereiiti'lo'dytlius"obtained is then reimp regnated :nitlmcarbnnaceousmaterial and Ychar;ed.,.,and the treatment 'repeated until the desired hardness, heat con` ductivity and mechanical strength are imparted. rI'he higher the temperature ot' the carbonization, the better adapted is the shaped article for the present purposes since carbon shrinks and becomes denser at. very high temperaiures with concomitant increase in heat conductivity. The temperature .of the electric furnace is well adapted for this purpose. Electrically heated and condensed carbon, such as the synthetic graphites and other forms of condensed carbon, is now"onth'inarket and may well be used :tor the present purposes, either after a preliminaryr commii'iution, impregnation and recharring to obtain desired shapes, or, when in suitable shapes and sizes, and of suitable density, it may be directly employed as found in the market. The electrode carbon of the market may, t'or instance, be directly en'ploycd when of good density and of proper shapes and sizes to allow assemblage to form a mold liner, or when it may be cut or shaped to such shapes and sizes. However produced, the mold lincr'or liner segmentsv are next assembled with a metal casing, preferably steel. In this assemblage, the liner should be placed in as good thermal connection with the casing` as possible. For this purpose, the homogenized carbon slabs or blocks may have an external coating' et' plumbago paste when fitted to the sections of the mold cas-ing.

In the accompanying illustration I have shown, more or less diagrammatically,- cer tain forms of ingot mold under the present invention.

In said drawings: Figure l shows a top view and Fig. Q a central vertical section of one form of mold, constructed as above de.- sCribed. of sections of homogenized carbon, the -mold being adapted for forming round ingots. Fig. 53 is a top view, Fig. -t a vertical section and Fig. ,another vertical section taken on a plane at right angles to that et Fig'. l, showing another mold of the same general construction, but adapted for torming rectangular ingots` Fig. G is a detail .vie f showing one of the tastenings used for holding together the parts of the molds. Fig. T is a top View and Fig. 8 a side elevation of an alternative form of mold. I'iig. 9 shows a vertical longitudinal section and Pig. 'l0 sho a transverse section of a mold comprising a one piece homogenized carbon liner and a metal casing. Fig. ll shoivs such a carbon mold Without any metallic casing.

Referring first to Figs. 1 5 inclusive, the molds there shovvn are composed oit' a plurality of vlongitiulinal slabs or sections l or' honmgenized carbon surrounded by a metal ca ing iornied oi similar sections 2. Said melfls also have bottoms: composed of slabs 3 oi homogenized carbon oi-'thc like res 'ng upon metal bottom pl lies The longitudinal sections of the mold are held together by .suitable tastenings 5, such as are conn'nonly used for holding together the parts ot' molds,

and the main portions and bottoms of the molds are held together by Wedges G. Metal top rings 7 are held in place in similar fashion. Round molds such as shown in Figs. l and 2 are usually composed. of at least three longitudinal sections so that the mold might have no draft vertically, the mold be i,J separatedfrom the ingot cast in it by taking apart the sections of the mold. ln the case ot a rectangular mold, suoli as shown in Figs. 3, l and the sections oli` the mold may part upon one ot the diagonale as shovvn.

The fastcnings 5 comprise headed bolts 8 passing through flanges of the parts of the mold, and Wedges 9 driven through slots in said bolts. v

To facilitate the separation of the sections ot the mold I commonly lay sheets of asbestos paper or the like l0, between the sections.

Before charging a inold such as described, with molten metal, l commonly heat it to a high temperature by means of a iiame from a,suitable burner or by placing the mold, minus its bottom, over a furnace so that the products o1"- combustion from the furnace pass up through the mold.

In Figs. 7 and S I illustrate alternative means for holding the sections of themold together, comprising flexible chains or cables 1l passingaround the mold and arranged to be draivn up by means of turn buckles l2; the bottoms and upright portions of: the mold being held together by Wedges as previously described.

r[he dense homogenized carbon liner of the character described oxidizes very slowly, so that an ingot mold such as described may be used for very many operations, before redressing is required. li-requently it. may

'be used Ll'or as many as twenty times before rcdiessing is necessary. The carbon slabs `may be redressed by planing eti' the surface exposed to oxidation, and by then planing oll" the beveled edges, the mold may be restored to its original internal dimensions. The homogenized carbon slabs are not at all attached by flu-.ves nor do they give up detrimertal impurities to the metal cast therein, even when the latter is supermolten. I have found that molds such as described are so strong and heat conductive and so little liable to crack, that they may be safely quenched in Water or by a jet ot Water play ed on them or by blowing a current ot cold air against them; and this chilling is tulte desirable, as it permits the rapid cooling or' the supermolten metal; something that is particalarlyT desirable when carryiii out the process or' coating set forth in my Patent lo. 853,716, as, it' the mold may be rapidly cooled, the solid billet to be coated by said process may be heated initiallg to a 'somewhat higher temperature, since there "s no netcssity Jfor depending upon invvaril soaking of heat into the billetto take up the heat of the supermolten contacting metal after formation of the union, and aitcr such union occurs, the Whole mold may be safely quenched by immersion in vvater or ijf sprayed water. rIhis otter-s the advantajvf/es that on the one hand the higher ytemperature of the solid metal facilitates the union. and on the other the supermolten metal need not be quite so hot since it docs not have to afford so much heatto the billet in ra` ing the abutting layer to the uniting temperature. And the time during which the supe rinolten temperature erists atl the abuttingy l.: *ers oit' the tivo metals may be very prccif-iely regulated, since the mold and contents may be suddenly chilled at the time desired. n

I-Ioinogenii-ed carbon of the character described is also Very strong mechanically and sutlers` practically no erosion or mechanical injury from poured metal. Its rate of eX- pansion and shrinkage under temperature changes is also such that it does not part from the containing casing, or lose its thermal contact ilercivith.

The homogenized carbon liner need'not necessarily ba in sections or Slabs, but may be in one piece. In Figs. 9 and l0 I have illustrated src i a mold comprising' a hollow one piece lini, 153, within a tubular casing la. In this mild the otlice of the casing is of course tf, give increased mechanical strength to facilitate the securing together of the various s labs of a sectional mold, such as mustbe und when the casting is to have no draft o`-taper, and to withstand the mechanical action of clamping means such as employed. l3nt since a good quality of dense homogenized carbon, such as is 'contemplated in the present. case, often has a considerable degree oit mechanical strength,

itis practicable to use such carbon either in one piece or in a plurality of slabs or seciii-ins without any external metal casing. Diepensing With this casing is indeed in many cases a distinctadvantage since it also dispenses with the necessity of providing good thermal contact between liner and casing. and permits cooling of the liner direct.V

`Where the easing is employed, in procuring goed thermal Contact with the liner iii lieu ot' graphite paste, a metallic paste Such as that which may be made from tinel)T powdered iron or the like, may be employed. Such highly conductive metal powders serve Very Well to forni perfect thermal connection between liner and casing.

l. iii ingot mold comprising a metal casing and a liner of dense homogenized carbon in thermal contact therewith, the particles of Such carbon being also in mutual thermal Contact and ii'iolecularly bonded.

/, 2. An iiigot mold comprising a metal casing and a homogenized dense carbon liner -for the same, said liner being sectional and 2cizhe sections being united with graphite.

8. An ingot mold comprising a metal casing, a liner of dense homogenized carbon having its particles in mutual thermal contact and a heat conducting layer ot graphite between such casing and liner.

et. An iiigot mold comprising a metal cas ing and a liner of electrode carbon in thermal Contact therewith.

5. An ingot mold coii'iprising a metal casing and a liner of grapliitoidal electrode carbon in thermal Contact therewith.

6. A mold for forming castings from fluid metal7 comprising a hollow container of dense homogenized carbon having its particles in good thermal contact, Said mold being adapted for rapid cooling of said con tainer. d

7. A mold to forni lcastings from fluid metal comprising -a hollow container composed ot' sectifins of homogenized carbon, Said cai-bon ha 'sing its particles in good thermal contact, and Said container being adapted for rapid cooling.

In testimony whereof I atlix my signa# ture, in the presence of two witnes JOHN F. MONXOT. ll'v'tnesses:

Il. M. MARBLE, f K. P. MCELnor.

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