US1126079A - Casting metals of high melting-point. - Google Patents

Description

A. L. J. QUBNEAU. CASTING METALS OF HIGH MEI-TING POINT.

APPLICATION FILED JUNE19,1909. RENEWED N ov. 25, 1914.

LIQE QWQ Patented Jan. 26, 1915.

2 SHEETS-SHEET 1 A. L. J. QUENEAU. CASTING METALS OF HIGH MBLTING POINT.

APPLICATION FILED JUNE 19.19094 w 1 l 26MB M I.

RENEWED NOV. 25,1914.

Patented Jan. 26, 1915.

2 SHEETSSHEET 2 UNITED STATES 'OFFI1CE.

anens'rm LEON JEAN QUENEAU, or rmna nmnm, ,rnnnsytvenm' as'sronon, BY MESNE ASSIGNMENTS, TO SAMUEL r. wna amnnybr" neewmzarm nnw JERSEY.

To all whom it may concern:

Be it known that I, AUGUSTIN LEON JEAN QUENEAU, a citizen of the Republic of France, residing in the city of Philadelphia, county of; Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Casting Metals of High Melting-Point; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will .enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the electrical casting of metals and more particularly to an electrical casting furnace adapted to produce finished castings from metals Which melt at high temperatures such as brass, phosphor bronze, manganese steel and the like. So far as I am aware, no means have been known, prior to my present invention, for producing finished castings from these and like metals of such high melting point.

In carrying out my invention, I maintain the casting metal in the fluid condition essential to the production of sound. castings, by subjecting it to the heating effects of an electric current, and I maintain the casting nozzle which introduces the metal into the mold at a correspondingly high temperature,- likewise by the heating efiect of an electric current, applied either directly or.

indirectly thereto as hereinafter described. With the casting metal and the casting nozzle at these high temperatures, I thereupon raise the casting metal into the mold by creating an appropriate pressure upon the surface of the metal, and maintaining the pressure until the mold is filled and the casting therein has sufficiently set; whereupon, by withdrawing or diminishing the pressure, the casting metal remaining in the nozzle is free to drop back into the receptacle containing the main body portion. The employment of the electric current for heating the casting nozzle permits the temperature of the nozzle to be maintained at a degree even higher than the fusion point of the casting metal itself, by appropriately calibrating the crosssection and resistivity of the material constituting the casting nozzle to the current employed for maintaining the fluidity of the casting metal in the metal receiver or container of the furnace. I may CASTING METALS OF HIGH MELTING -POIIVTr Specification of Letters ratent. Patented Jai 26,1915 Application filedJunc 19, 1999, Serial N0. 503,095 I i I i I I i Renewed November .25, .1914. gerlaLNu. 874,092.

conveniently employ the same circuit both for heat ng the metal in the container and o h i g the cast ng nozzlel Further features ,of my invention consists in various features Of Construction, incident to its practice and which have application generally to furnaces .which may be designed to operate upon the same fundamental principles.

In the accompanying drawings, Figure 1 represents in ,vert cal. section one form or modification of an electric furnace and its adyunctsfor the practice of my invention, and F g. 2 represents a like View of another form or modification thereof.

Similar letters indicate similar parts in both views.

In the electric casting furnaces illustrated in the drawings, it will be recognized that the furnace structure consistS'generical ly ,of a construction having a metallic outer shell of such inherent strength as to resist with safety the high pressures found desirable for maintaining the best results in apparatus of this character, and that the metal to be cast is contained within a suitable well or hearth constituting a receptacle therefor ,and which may conveniently, though not necessarily, be a crucible of the kind employed for the melting of steel, 2'. e.,'

the familiar Dixon graphite crucible made of a composition of'flake graphite and fire clay. It will, of course, be apparent that, generically considered, the invention is not restricted to any particular dimensions of the furnace body or to any particular shape, size or configuration of the retaining receptacle of the casting metal, the forms illustrated being, however, well adapted to the purposes for which the invention is intended.

In the furnaces shown in the drawings, the main body portion thereof is illustrated as consisting of a stout metallic shell A which may conveniently be cast in the form shown from cast steel. It is provided with a cover B which may likewise be conveniently cast from the same or like material. These parts are adapted to be securely bolted together, as shown, by means of suitable screw of non-conducting material, such as asbestos so as to insulate the two castings from each other. I So also,.the shanks of the. bolts are provided with flanged insulating sleeves b, which serve to insulate the bolts and nuts from the flanges of the shell, but which, as shown at the right-hand side of Fig. 1, permit the leads a from an electric circuit to be respectively clamped into reliable electrical contact with' the body A'and cover B IGSPBO'. tively. Although I do not restrict myself to the employment of any particular source of electric current, I have foundit convenient to employ in some instances a single phase alternating current derived from the secondary circuit of a transformer, which readily permits the obtaining of heating effects suflicient to maintain at the proper degree of fluidity for casting purposes, metals of high melting point such as brass, phosphor bronze, manganese steel, and the like.

The body portion A of the shell may conveniently be provided, in the form of furnace shown in Figs. 1 and 2, with a step or projection e cast integral therewith, as shownv in Fig. 1. This step constitutes a part of a pedestal, whose other portion 7 supports the metal container C for the casting metal. The receptacle or container 0 may be provided with a cover 9 having a charging opening it normally closed by a plug 2', and the cover B may likewise be provided with a suitable aperture adapted to be closed by a removable screw-threaded stopper j so as to replenish the contents of the receptacle C from time to time as desired. Where the cost of the electric cur- .rent exceeds that of fuel it will be found preferable to melt the casting metal in a separate furnace before supplying it to the receptacle C, in which event, the heating effect of the electric current will be employed mainly for supplying radiation losses or for raising the temperature of the metal in special instances where it is desirable to do so for castings of more or less complexity.

A conduit D communicating with a source of pneumatic pressure opens into the interior of the furnace through a three-way cock having an operating handle E; so

that by manipulating 'the handle compressed air at high pressure may be admitted into the interior of the furnace when desired and so that by shifting the handle the pressure may be discharged at the termination of the casting operation through the exhaust F. For obtaining the best results I find it desirable to employ heavy pressures for the castin operations, e. pressures from 100 poun s to the square inch upwardly, so as to obtain prompt lifting action, the time factor being of importance and also a heavy pressure" being desirable to feed the shrinkage in the castings and to avoid piping. Accordingly, it will be apparent that the metal shell of the furnace must be of corresponding strength to withstand the internal pressure thus created, and especially to withstand such ressure when the furnace is operating at t e extremely-hi h temperatures incident to the resence of t e large body of casting meta contained in the inner receptacle.

In order to protect the casting metal from excessive loss of heat by radiation, the space between it and the metallic shell of the furnace is filled in with blocks or bricks of fire clay or the like. Nevertheless, just suflicient space is provided to permit the incoming compressed air to find its way promptly through small channels and interstices to both the interior and the exterior of the container, thereby equalizing the air pressure upon the walls of the container and preventing any preponderance of ine ternal strains.

The electric heating current for maintaining the casting metal in the desired fluid casting condition is introduced into the metal by means of a combined casting nozzle and electrode. In the form or modification of the invention shown in Fig. 1, this conbined casting nozzle and electrode consists of a single element to'wit, adepending tube Z having a top flange m. For brass, phosphor bronze, and other metals inert to carbon the castin made of some highly refractory form of carbon, such as graphitized carbon, which is particularly adapted for the urpose for the reason that it may be readi y machined and has the necessary conductivity to heat and suflicient electrical resistance so that it may be relied upon to attain a high tem perature on the passage of the electric current through it, superior to the melting point of the metal. The nozzle may also be conveniently and satisfactorily 'made from the ordinary graphite crucible mixture of flake graphite and fire clay mixed in such proportions as are customary for the manufacture of so-called graphite crucibles. In fact, a casting nozzle of this composition will be found to have a resistance higher than graphitized carbon, and this resistance can be graduated within wide limits by varymg the relative quantity of graphite in the mixture. In either case it will be found desirable, for the purpose of making a reliable air-tight joint having conductive capacity nozzle will preferably beto form a number of concentric grooves in efficient air-tight joint and gives the necessary conductivity but is also a suflicient lubricant to permit the screw-threaded pressure ring or cup n .to be screwed down to the desired limit without danger of breaking the flange m by torsional strains exertedupon alsobe made-of some other carbonaceous material inert .to the particular temperature of.themelting point ofthe metal under treatment,,as for instance carborundum; ,or, when iron or steel is the metal to-be-cast, the casting nozzle may be .made of, magnetite or of a mixture of magnesia and tar, which mixture after being molded into the form of the nozzle may be subjected-to extremely high heat until the tar, has-been destructively distilled. Sometimes a, nozzle of, this kind is a secondary conductor for the current to be employed, that is, it becomes a primary conductor after beingraised-toa suflicient temperature ,by' first subjecting it to heat in any desired way.

The combined casting nozzle and electrode may in some instances consist of two-elements, as shown, for instance in-Fig. 2, wherein the electric current is introduced into the casting metal by means of the part Z which in turn heats the inner part Z mainlv by radiation, the proximity of the two elements of the nozzle in this instance permitting the sufficient heating of the element Z In most cases it will be found preferable, to have the element Z of tubular form although this is not absolutely necessary and it may in fact be slotted longitudinally or spirally or be provided with holes to increase the heating effect; and, in fact, even when otherwise imperforate it will be desirable to provideat least one through perforations so as to equalize the pressure within and without the element Z, thus preventing the metal from rising into the space between Z and Z during the casting operation. In the form of the invention shown in Fig. 2, the parts Z and Z are both made of graphitized carbon or of other suitable refractory material appropriate to the purpose as hereinbefore set forth and the lead to the combined casting nozzle and electrode consists of a water-cooled copper conductor t passing through an insulated stuiiing box in the cover B. The requisite pressure upon the element Z is obtained by a steel screw cap n as in the form shown in Fig. 1, the flange on being insulated from the walls of the recess 1* and from the screw cap a by asbestos or similar intervening insulating material as shown.

It will be apparent that whether the combined casting nozzle and electrode for introducing theelectnic cur-rent into the castmetal .isaai single .element as shown in '1Fig.;1.-,or ;is ;made up of: a plurality of elements in .the Lnecessary heat conducting ,proximity to each other as shown in- Fig. 2, 1

the, purposes of the invention will be subserved, that is, notonlyto provide the necessaryamount of; current forkeeping the casting metal in, thedesired fluid. casting con-- v,d ition but-also to-maintainthe temperature of; the. ductthroughwhich the casting metal w marked that while I prefer a cylindrical tubular form for the combined casting nozzle and electrode, it may, in some in- .stances, be of other configuration, as, for.

. example. ,of 1 rectangular form 111 cross-section,having one or more of theisides of the rectangle omitted. If the-outer element Z -.ofFig.--2 is. spirally slotted, there will be addedto the. heating efiect due to the resistivity of the tube, whatever inductive heating efiect incident to the ampere turns of the spiral.

The casting of the metal at high melting point is effected in a metal. mold which is adapted to be quickly attached and detached from the cover B of the mold, in such manner that the gate of the mold will form a continuation of the duct of the casting nozzle. This may be conveniently effected. by providing the mold with a screw-threaded projection v engaging a screw-threaded recess in the cap n. The casting recesses 01' of the metal mold are preferably given a light coating of graphitized carbon powder brought to a fluid consistency in oil. The entire gate of the mold, including also that portion m which receives the impact of the metal as it is lifted by the air pressure into the mold, is formed of a refractory carbon compound preferably graphitized carbon.

In the form of the invention shown in Fig. 2, the connections are shown for supplying the electric heating current of the furnaceby means of a two-phase or threephase current instead of the direct ciu'uw-t or the single phase current connections illustrated in Fig. 1. Thus, in Fig. 2, the lead t supplies one of the phases, the remaining phase or phases, as the case may be, being supplied through the support 6 cast integral with the shell A and through the support a which passes through an air-tight joint insulating it from the shell A, the receptacle C for the casting metal being supported upon The lead e may conveniently enter the furnace through a screw-threaded projection e, and, in order to effectively seal the opening against leakage of 'air, and also for the purpose of insulating the lead from the shell of the furnace it is provided with the insulating packing e e and the. screw cap 6. So also, the lead at which is screw-threaded into the flange m is provided with an adjunct t which is insulated from the cover B of the furnace by the packing t t made air tight by the screw-cap t which engages the screw-thread of the projection it, through which the adjunct t enters the interior of the furnace.

What I claim is:

1. The method of making a successionof castings in a single mold from a bath of 'casting metal of high melting point, such as brass, phosphor bronze, manganese steel and the like which consists in maintaining the bath of metal in fluid casting condition by the passage of an electric current therethrough, maintaining by the electric current the temperature of the duct through which the casting metal is led into the. mold at a degree higher than that of the main body portion of the molten metal, raising the metal into the mold by pneumatic pressure, and feeding the shrinkage of the casting, until it is set, by the metal maintained fluid in the electrically heated duct; substantially as described.

2. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like, said furnace being provided with a receptacle for the molten metal to be cast; a combined casting nozzle and electrode dipping into the said receptacle below the level of the molten metal therein; means for supplying therethrough the electric heating current su'flicient to maintain the metal in a fluid casting condition and to prevent it from chilling in the casting nozzle, whereby, at the termination of each casting operation, the fluid metal present in the nozzle may flow back into the receptacle; and means for producing at will a pressure in the furnace sufiicient to raise the molten metal through the nozzle, substantially as described.

3. An electric casting furnace for metals melting at high temperatures, such as phosit from chilling in the casting nozzle, whereby, at the termination of each casting operation, the fiuid'metal present in the nozzle may flow back into the receptacle; and means for producing at will a pressure 'in the furnace sufficient to raise the molten metal through the nozzle; substantially as described.

4. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like, said furnace being provided with a receptacle for the molten metal to be cast; a casting nozzle of graphitized carbon dipping into the molten-metal; means for supplying therethrough an electric heating current sufficient to maintain the metal in a fluid casting condition and to prevent it from chilling in the casting'nozzle, whereby, at the termination of each casting operation, the fluid metal present in the nozzle may flow back into the receptacle; and means for producing at will a pressure in the furnace sufficient to raise the molten metal through the nozzle; substantially as described.

5. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like, said furnace being provided with a receptacle for the molten metal to be cast, said receptacle consisting of a retainer exposed raise the metal through the dip-nozzle; substantially as described.

6. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like said furnace being provided with a cover plate having a containing recess, a dip nozzle provided with a top flange restlng within said recess, and a retaining cap for said recess above the flange of the nozzle; substantially as described. 2

7. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like said furnace being provided'with a cover plate having a containing recess, a (lip nozzle provided with a top flange resting within said recess, and a retaining cap for said recess above the flange of the nozzle, such cap being provided with means for detachably securing a casting mold in place; substantially as described.

8. An electric casting furnace for metals melting at high temperatures, such as phosphor bronze, brass, manganese steel, and the like said furnace being provided with a cover plate having a containing recess, a dip nozzle provided with a top flange resting within said recess, and a retaining cap for .said recess above the flange of the nozzle, said retaining cap being provided with a screw-threaded connection to the walls of the recess so as to exert pressure therein, the joints between the screw cap, dip nozzle flange and recess being provided with suitable packing; substantially as described.

9. An electric casting furnace for metals melting at high temperatures such as phosphor bronze, brass,'manganese steel, and the like, the body portion of said furnace consisting of an air-tight metallic shell adapted to resist high pressures, a metal container mounted upon'a conducting pedestal, brick work occupying substantially the entire space between the metal shell and said container and pedestal with the exception of minor spaces for the access of a pressure fluid to the exterior and interior of the container, means for admitting at will a pressure fluid to the furnace, a combined casting nozzle and electrode dipping into the container below the metal level therein, and means for supplying an electric current to the furnace through the dip nozzle, the container, its molten metal contents and the said conducting pedestal; substantially as described.

10. In an electric casting furnace for 4 metals melting at high temperatures a main body portion consisting of a metal shell having an air-tight cover and adapted to resist high internal pressure, means for supplying fluid pressure thereto, a metal container occupying a substantially central position within the shell and exposed externally and internally to the pressure prevailing within the shell, refractory brick work interposed between the metal container and the interior of the shell, a casting nozzle scribed.

11. In an electric casting furnace for metals melting at high temperatures, a casting dip nozzle, consisting of current conducting carbonaceous material of such crosssection and resistivity as to be capable of being raised to a temperature higher than the melting point of such metals as brass, phos hor bronze, manganese steel and the like y the passage of an electric current; substantially as described.

12. In an electric casting furnace for metals melting at high temperatures, a metal container for metals of high melting point such as brass, phosphor bronze, manganese steel and the like, and a castin dip nozzle for introducing into said meta an electric current suflicient to maintain it in fluid casting condition, said dip nozzle bein of such cross-section and resistivity as to raised to a temperature higher. than the fusing point of the casting metal by the electric current which suflices for fusion; substantially as described.

13. An electric casting furnace for metals melting at high temperatures, such as brass,

' hosphor bronze, manganese'steel and the Ike, the cover of said furnace bein provided' with means for attaching and etaching a casting mold, a casting nozzle, of refractory material in alinement with the gate of the mold, a metal container within the furnace, into which the casting nozzle dips, and means for introducing into the contents of the container and throu h the casting nozzle an electric current su cient to maintain the metal in fluid casting condition and to raise the temperature of the nozzle above the fusion point of the metal; substantially as described.

In testimony whereof I aflix my signa- 95 ture, in presence of two witnesses.

AUGUSTIN LEON JEAN QUENEAU- Witnesses:

LILLIAN H. Bannow,

LAURA B. Pnnrmm.

Images