US2688781A

US2688781A - Self-eliminating core wire and core

Info

Publication number: US2688781A
Application number: US126858A
Authority: US
Inventors: Ernest D Fahlberg; Edward J Schwoegler
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-11-12
Filing date: 1949-11-12
Publication date: 1954-09-14
Anticipated expiration: 1971-09-14

Description

Sept. 14, 1954 FAHLBERG ET AL 2,683,781

SELF-ELIMINATING CORE WIRE AND CORE Filed Nov. 12, 1949 'INI'ENTORS.

"BY l V ATTOHN Patented Sept. 14, 1954 SELF-ELIMINATING CORE WIRE AND CORE Ernest D. Fahlberg, Madison, Wis., and Edward J. Schwoegler, Hammond, Ind.; said Fahlberg assignor to said Schwoegler Application November 12, 1949, Serial No. 126,858

Claims. 1

This invention is directed to core wires adapted for reinforcing sand cores utilized in the casting of metals.

In the manufacture of metal castings sand cores are utilized for forming internal cavities therein. These internal cavities often become quite complex and tortuous, as for example, the cooling passages in the cast metal blocks and heads for diesel and automotive engines. They are extensive and virtually honeycomb the castings. The sand cores used for forming these complex cavities or cooling passages are of necessity complex in configuration, extensive in size properly made and baked, are relatively fragile and are not self-supporting. They sag when placed in the mold and very often crack and break when contacted by the molten metal during pouring. of the casting.

To'remedy this difiiculty, it has been the practice for years to reinforce these complex sand cores with metal wires so that the sand cores would not sag, crack or break. It has been the uniform practice to use iron or steel wires for this purpose since such wires are relatively rigid, adequately reinforce the sand core for reasonable wire size and withstand the heat delivered to the sand by themolten metal being poured into the mold. It is not uncommon to incorporate as much as thirty feet of reinforcing steel wire in a sand core for forming the cooling passages of an automotive engine block or head.

However, the use of these steel reinforcing wires i i-sand cores introduced further problems I which have been of great concern to the foundry business as long as such wires have been utilized, namely, the removal of such wires from the cavities or passages of the completed casting. In

normal practice following the casting operation,

the completed casting is vigorously shaken for breaking up the sand core and shaking the same from the cavities or passages in the casting.

, Ready removal of the sand from the cavities or I passages is often impeded by the steel core wires consuming, tedious, nerve wracking and expensive task. It is necessary to probe into the cavities or passages to locate and remove the steel.

such as, dental forceps, mirrors, tweezers, cutting saws and the like. The tedious and nerve wracking nature of the work to remove the core wires is readily apparent and, when the amount of wire to be removed is considerable, it is obvious that the wire removal work is extremely time consuming. By reason of the character of the work,emp1oyees removing the steel wires are usually paid a premium rate. In many instances the steel core wire is not completely imbedded in the sand core with the result that the exposed wire is welded to the casting in the cavities or passages therein which further complicates the removal of the wire therefrom. The expense of removal of the steel core wires from the castings represents an appreciable portion of the cost of manufacturing the casting. The complete removal of the core wire from the castings is essential for failure to do so would, for example, result in impairment of the cooling system of an automotive or diesel engine. Steel or iron reinforcing wires will rust and thus build up a larger mass which will further clog the cooling passages.

Many attempts have been made in the past to remedy this important problem of core wire removal but all such attempts have been unsuccessful. For example, metals and alloys having low melting points have been tried to this end with the thought that they would melt and break down during casting. However, such wires were not successful for they did not have sufficient strength for reasonable wire sizes adequately to reinforce the sand core, they melted and broke down prematurely permitting failure of the sand cores before the molten metal had an opportunity to solidify sufiiciently to be self-supporting and some of such wires when contacted by the molten metal produced porous spots in the resulting casting. That these attempts have been unsuccessful is clearly evidenced by the foundry industrys continued use over the years of steel core wires with the attendant problems of manual removal thereof from the castings.

The principal object of this invention is to provide a self eliminating core wire which may 'of the core wire removal problems heretofore encountered.

In carrying out this object of the invention the core wire of this inventionincludes two metallic members, one, a continuous relatively rigid The first metallic member of high strengthand melting point is not directly affected by the heat of the sand core during casting and adequately.

reinforces the sand core until the molten metal of the casting has had an opportunity to solidify sufficiently to be self supporting. When the sec,- ond metallic member is subjected to the heat of the sand core during casting, it starts alloying casting has enough time to solidify sufiiciently to v be self supporting before the reinforcing elTect of the first metallic member on the sand core is eliminated. The disintegratable alloy thus produced becomes non-continuous and is readily shaken from the casting along with the core sand following the casting operation.

When the alloying action between the two metallic members issubstantially complete, the alloy fuses, ignites, breaks down or otherwise disintegrates into small particles which may readily be shakenwith the sand from the casting. In

production use of the self eliminating corewire of this. invention at least eighty percent of the core wire is normally completely disintegrated into small particlesnand the remaining 'portion,.

is at least partially located within a cavity in the first metallic member. In this respect the first metallic member may be provided with a groove having the second metallic member located therein, or the first metallic member may be in the form of sleeve or tube or sheath with the second metallic member in the nature of a wire located therein. In the. latter, construction the first metallic member in theform of-a sleeve or tube has maximum reinforcing strength for the thin wall thickness, operates to keep the second metal- .110 member wholly confined therein to provide maximum alloying e'ificiency, prevents the second -metallic member from producing deleterious whichmay not have substantially complete alloying, is represented by short lengths of extremely weakened and friable material.

If such short lengths of core wire, when they exist, are not shaken from the casting with the core sand, they ber has a high melting point and sufficient strength adequately to reinforce the sand core during casting, that the second metallic member I is intimately associated with and capable of al- ,loying with the first metallic member at the temperature of the sand core during casting, and

, that there is a sufiicient amount of the second metallic member to substantially completely weaken or eliminate the first metallic member by alloying therewith. The metallic members may each. be formed of suitable base metals or .compoundsor alloys or combinations of metals,

The core wires of this invention should, in addition to having-sufiicient strength adequately to support the sand core during casting, be ofrelatively small cross sectional area so that they may i be readily incorporated in the sand'cores. They may" have any desired cross sectional configuration but, preferably, the second metallic 'member effects .upon the casting, and assists in preventing the core wire from adhering to the casting. The sleeve or tube or sheath forming the first metallic member may be secured on the wire forming the second metallic member in various ways, as for example, by plating the wire, by inserting the wire into the tube and drawing the tube against the wire, or by extrusion. I v I Further objects of this invention residein the details of construction of the self-eliminatingcore wire andthe cooperativerelationship between the component parts thereof.

Another object of this invention resides in the combination of the sand core and the self-eliminating core wire for producing a reinforced sand core which may be readily removed from the casting following casting thereof. 1 I

Further objects of this invention reside in the method of making reinforced sand cores which may be readily removed from castings following casting, thereof and in the method of.making castings by utilizing such reinforced sand cores.

Other objects and advantages of this invention will become apparent torthose skilled in the art upon reference to the accompanying specification, claims and drawings, in which;

Fig. 1, by way of illustration, is a perspective phantom View ofoa typical sand core for forming the cooling passages in a head block .of an automotive engine showing the core wire of this invention imbedded therein for reinforcing the sand core; a

Fig. 2 is a sectional view taken substantially on a plane transverse to that of Fig. 1;

Fig. 3 is an enlargedcross sectional view of-th preferred form of thecore wire of this invention, and

Figs. 4 to Bare enlarged :cross sectional views illustrating modified forms of the core wire of this invention.

Referring first to Fig. .1 there is illustrated by way of example a typical sand core 10 for forming .the cooling passages in a head block of an automotive engine. The sand core in is provided with openings 1 l corresponding to the cylinder locations and openings 12 corresponding to the valve locations. The sand core may be formed in conventional manner from conventional core sand. It will be noted that the sand'core "is quite complex in configuration, is quite extenably reinforced, it. would sag when placed in the mold and would undoubtedly crack or break when contacted by the molten metal during pouring of the casting. I

To reinforce this sand core and to prevent sagging, crackingor breaking thereof, core wire 13 of this invention is imbedded therein during the making of -'the sandcoref The core wire [3 extends throughout the sand core l and around the openings l I and I2 and has suflicient rigidity and strength adequately to reinforce the sand core throughout. It is readily apparent from Fig. 1 that considerable difliculty is involved in locating and. removing conventional steel core wires from the cooling passages formed by the sand core it] in the completed head casting. However, by utilizing the self-eliminating corewire 13 of this invention such difficulties of removal are entirely eliminated.

A cross section through the preferred form of the core wire l3 of this invention is illustrated on an. enlarged scale in Fig. 3. It comprises a first metallic member in the form of a sleeve, tube or sheath M which encompasses and is intimately associated with a second metallic member in the form of a wire [5, the core wire l3 being circular in cross section. The metallic sleeve [4 has a 4 melting point higher than the temperature of the sand core during casting so that it will not be directly affected by theheat from the sand core and sufficient strength andrigidity adequately to reinforce the sandcore. The metallic composition-of the metallic wire [5 is different from that of the metallic sleeve I l and it is capable of alloying with the metallic sleeve I4 atv the temperature of the sand core during casting. When the core wire i3 is subjected to the heat of the sand core during casting, the two metals alloy whereby the metallic sleeve 13 is absorbed and a disintegratable alloy formed which becomes non- .continuous so that it is readily removed from the casting following casting thereof.

For relatively rapid and complete alloying. action and for reasons of economy and manipulation, the outside diameter of the core wire 13 and the wall thickness of the sleeve [4 are made as small as possible commensurate with the metals used and the strength and rigidity of the core wire. Best results have been obtained by maintaining the outside diameter of the core wire within the range of .032 to .25 inch and maintaining the wall thickness of the sleeve within the range of .0001 to .015 inch. Percentagewise the amount of the metallic sleeve is usually less than the amount of the metallic wire and accordingly substantially complete and relatively rapid adsorption of the metallic sleeve by the alloying action is provided. At thesame time very little in the way of strength and rigidity is lost by having a small wall thickness in the metallic sleeve for a sleeve or tube has almost as much strength or rigidity as a rod of the same outside dimensions and composition. The thin walled metallic sleeve therefore causes the core wire adequately to reinforce the sand core and yet is relatively rapidly and completely absorbed in the alloy formed thereby during casting.

The metallic sleeve I4 is formed from metals having relatively high melting temperatures and relatively high moduli of elasticity to provide adequate strength and rigidity for sand core reinforcing purposes. In the manufacture of iron and steel castings the molten metal is usually poured at temperatures from 2400 to 2900 F. with a resulting rise in temperature within the sand core at the core wires to from 1300 to 2300 F. Thus "commensurate with small wire size and sleeve wall thickness, preferably, should have a modulus of elasticity of atle'ast 15- 10 lbs/m2. Various metals. and alloys of metals having these characteristics are satisfactory for forming the metallic sleeve [4 of this invention, as for example, iron, steel, stainless steel, nickel, copper, molybdenum, manganese, tungsten, cobalt, beryllium, iridium, tantalum, alloys thereof, and the like.

The metallic wire 15 is formed from metals which are capable of alloying with the metallic sleeve M when subjected to the temperature of the sand core during casting. The strength and rigidity of the metallic wire l5 need not be high for it. is reinforced by the relatively strong and rigid metallic sleeve I d. All that is necessary is that the combination core wire has sufficient strength adequately to reinforce the sand core. However, the metallic wire I5 is of a type having a relatively low meltin point, and preferably below thetemperature of the sand core during casting, in order substantially rapidly and completely to perform the alloying action and the absorbing of the metallic sleeve I4. Various metals and alloys of metals having these characteristics are satisfactory for forming the metallic wire [5 of this invention, as for example aluminum, zinc, silver, magnesium, copper, alloys thereof and the like.

The metallic sleeve [4 may be applied to the metallic wire 15 in various ways as by inserting the wire in the sleeve and then drawing the sleeve down on the wire, by forming a clad billet and drawing the same down to the desired dimensions of by plating the sleeve on the wire. Depending upon the compositions of metallic sleeve I4 and the metallic Wire i5 in making up the core wire I3 of this invention the alloys produced thereby may be solid solutions or eutectics or may include one or more combining reactions of the metallic phases. However, the particular nature of the alloy is of no great importance so long as substantially rapid and complete alloying takes place at the temperature of the sand core during casting. Preferably, the metallic wire I5 becomes molten during alloying to expedite the alloying action. Where there is combining reaction between the metallic phases of the metallic members, as in the case of aluminum and nickel, it is not absolutely necessary that the resulting alloy reach a molten stage since such alloy is extremely friable and readily disintegrates. Where, however, the alloy formed in accordance with this invention is a solid solution or a simple eutectic, the alloy must reach a molten stage so that it may disintegrate into globules by the action of surface tension.

As a specific example of successful production use of core wire of this invention, a sand core for producing cooling passages in a ferrous engine block was reinforced by substantially 30 feet of core wire of .064 inch outside diameter consisting of a 2S0 aluminum w re plated with a .0015 inch Perflow nickel Wall. There was no sagging, cracking or breaking of the sand core indicating that the sand core was adequately reinforced and all of the core wire was disintegrated and shaken out of the casting along with the core sand. There was no sticking of the core to the engine block. Thus, perfect results were obtained.

A few more specific examples of core wires and the results obtained thereby, representing a small portion of the many types of core wires successfully tested, are set forth as follows:

Core wire produced by plating 0.093 zinc wire with 0.0005 copper and then 0.001 nickel was used to reinforce the sand Core used in the castin of a special metal bushing. The core withstood the example, those illustrated in Figs. 4 to 8.

pressure of the molten iron during casting and the core wire disintegrated and disappeared by being ignited by the heat of the. sand core. The sand core and disintegration products were easily shaken from th casting. The core wire did not stick to the casting nor did the Wire cause any blowing.

.Another type of core wire was produced by plating a magnesium alloy wire 0.080 inch in diameter with a dull nickel to the extent of 0.0017 inch thickness. Twenty-six feet of this Wire were utilized to support the cores of an engine block mold and the engine block was cast with these cores. As in the other instances the core wire disintegrated and the products were readily shaken out. The few larger fragments (1 inch) were tube-like in shape and crumpled easilyon slight pressure between thumb and forefinger. The wires did not stick to the casting nor in any way injure the final casting.

Ayellow brass wire 0.062 inch in diameter and tempered to what is commonly called half hard in the wire industry was cleaned by anodic and cathodic cleaning, given a flash coating of copper from a copper cyanide bath and then plated with a ductile semi-lustrous nickel to the extent of 0.0015 inch in thickness. The resulting core wire, which was more rigid than the original brass wire, was used to support cores for use in casting engine blocks. Molten iron heated to approximately 2800 F. in an electric furnace was used in making these engine blocks. The wires mentioned above adequately supported the cores and the few small fragments remaining after alloying during the casting operation were readily removed with the sand from the casting. No sticking of wire fragments was noted and a clean casting was obtained.

A tube made of stainless steel having an inside diameter of 0.056 inch and an outside diameter of 0.062 inch was used to encase a zinc wire 0.054 inch in diameter. The steel tube was snugly drawn to the wire. This core wire was utilized to support a core used in making a special steel bushing. After casting it was found that the core wire had disintegrated to small fragments which were readily shaken out with the sand resulting in a clean casting.

While the foregoing description of this invention has been directed primarily to a selfeliminating core wire having a cross sectional configuration like that illustrated in Fig. 3, many other cross sectional configurations may be utilized for obtaining comparable results, as for In Fig. 4 the core wire I3 is substantially square in cross section rather than round as in Fig. 3. In Fig. the first metallic member I4 is channel shaped with the second metallic member I5 located in the channel. The core wire I3 of Fig. 6 is like that of Fig. 5 except that the ends of the channel shaped metallic member I4 are formed over the second metallic member I5 more completely to enclose the same. The core wire I3 of Fig. '7 is like that of Fig. 6 except that it is generally circular in cross section rather than generally square. Likewise, the core wire I3 of Fig. 8 is like that of Fig. 5 with the exception that it is generally circular in cross section rather than generally square.

Self-eliminating core wires having appropriately selected constituent parts of proper dimensions may be constructed and used in accordance with this invention for adequately reinforcing substantially any type of sand core for casting substantially any metal or alloy. All

that is necessary is that the core wire have suflicient strength and rigidity adequately to reinforce the sand core and yet relatively rapidly and completely alloy at the temperature of the sand core during casting to form a disintegratable alloy which becomes non-continuous for ready removal from the casting. Thus the sand core construction and the sand core temperature during casting dictates to a great extent the construction of the self-eliminating core wire of this invention. However; for any given situation a suitable self-eliminating core wire may be readily constructed in accordance with this invention. 1

While for purposes of illustration several forms of this invention have been disclosed, other forms thereof may become apparent to those skilled in the art and therefore this invention is to be limited only by the scope of the appended claims.

We claim as our invention:

1. A self-eliminating core wire for use, and adapted to be imbedded, in a sand core for reinforcing the same during casting of metals which are cast at temperatures at which iron and steel are conventionally cast and readily removable from the metal casting following casting thereof comprising, acontinuous relatively rigid nickel member imparting sufiicient strength to the core wire adequately to reinforce the sand core, and a member selected from the group consisting of magnesium and magnesium base alloy members encompassed at least in the main by and secured to said nickel member and capable of alloying with said nickel member at the temperature of the sand core during casting for forming during casting a disintegratable alloy by combining reaction between the nickel and magnesium or magnesium base alloy members which becomes non-continuous for ready removal from the casting following casting thereof.

2. A reinforced sand core structure for use in casting of metal and readily removable from the metal casting following casting thereof comprising in combination, a core formed of sand, and

self-eliminating core wire imbedded in the sand core for reinforcing the sand core and including a continuous relatively rigid first metallic member imparting sufiicient strength to the core wire adequately to reinforce the sand core and having a melting point higher than the temperature of the sand core during casting and a; second metallic member encompassed at least in the main by and secured to said first metallic member and capable of alloying with said first metallic member at the temperature of the sand core during casting for forming during casting a disintegratable alloy which becomes non-continuous, the core sand and non-continuous core wire being,readily removed from the casting following casting.

3. A reinforced sand core structure for use in casting of iron and steel metal and readily removable from the metal casting following casting thereof comprising in combination, a core formed of sand, and self-eliminating core Wire imbedded in the sand core for reinforcing the sand core and including a continuous relatively rigid first metallic member imparting sufficient strength to the ,core wire adequately to reinforce the sand core and having a melting point higher than the temperature of the sand core during casting and a second metallic member encompassed at least in the main by and secured to said first "metallic member with said first metalli'cmemb'er at thetemperatime of the sand core' duriiig casting for forming andcapable of alloying during "casting 'a disintegratable' alloy by combining reactionlbetween'the'metallic phases of said two metallic members'whichfbecomes noncontinuous, the "core; sand and non continuous c'ore wire being readily removed v from-the casting following casting thereof.

- 4.A reinforcedsandc'ore structure for use in' casting of iron and steel metal and readily removable from the metal casting following casting thereof comprising in combination, a core formed of sand, and self eliminating core wire imbedded in the sand core for reinforcing the sand core, and includinga continuous relatively .rigid first metallic member, having a modulus of elasticity of at least x10? lbs./in. ,;and imparting sufficient strength to the, core wire adequatelyto reinforce the sand core andhaving a melting point higher than the temperature of the .sandcorejduring castin and a second metallic member having a melting point less. than the temperature of the sand core during casting, said second metallic member being encompassed at least in the main by and secured to said first .metallic .member and capable of alloying with said first member at the temperature of the sand core during casting for forming during casting a disintegratable alloy whichbecomes non-continuous, the core sand and non-continuous core wire being readily removed from the casting following casting thereof.

5. A reinforced sand core structure for use in casting metal and readily removable from the metal casting following casting thereof comprising in combination, a core of sand, and self- ,eliminating core wire imbedded in the sand core for reinforcing the sand core and including a continuous relatively rigid first metallic member imparting sufiicient strength to the core wire adequately to reinforce the sand core and having a melting point higher than the temperature of the sand core during casting and a second metallic member having a melting point less than the temperature of the sand core during casting, said second metallic member being encompassed at least in the main by and secured to said first metallic member and capable of alloying with said first member at the temperature of the sand core during casting for forming during casting a disintegratable alloy by combining reaction between the metallic phases of said two metallic members which becomes non-continuous, the core sand and non-continuous core wire being readily removed from the casting following casting thereof.

6. A reinforced sand core structure for use in casting of metal and readily removable from the metal casting following casting thereof comprising in combination, a core formed of sand, and self-eliminating core wire imbedded in the sand core for reinforcing the sand core and inture of the sand core during'casting which be comes non-continuous, the core sand and noncontinuous core'wire being readily removed from the casting following casting thereof.

'7. A self-eliminating core wire for use, and adapted to be imbedded, in a sand core for reinforcing the same during casting of iron or steel and readily removable from the'iron or steel casting following casting thereof comprising a -metallic wire having an outside diameter within rigid nickel sheath having a thickness between about 0.0001 and about'0.0l5 inch, said sheath encompassing at least in the main and being secured to a magnesium wire, said nickel sheath having sufiicient strength adequately to reinforce the sand core and being capable of alloying with said magnesium wire at the temperature of the sand core during casting for forming during casting a disintegratable alloy which becomes non-continuous for ready removal from the casting following casting thereof.

8. A self-eliminating core wire for use, and adapted to be imbedded, in a sand core for reinforcing the same during casting of iron or steel and'readily removable from the iron or steel casting following casting-thereof comprising a brass wire encompassed-at least in the main in and secured to a nickel sheath, said-nickel sheath impartingsufiicient strength to the core wire adequately to reinforce the sand core and being capable of alloying with said brass wire at the temperature of the sand core during casting for forming during casting a disintegratable alloy which becomes non-continuous for ready removal from the casting following casting thereof.

9. A self-eliminating core wire for use, and adapted to be imbedded, in a sand core for reinforcing the same during casting of iron or steel and readily removable from the iron or steel casting following casting thereof comprising a relatively rigid stainless steel member imparting sufiicient strength to the core wire adequately to reinforce the sand core, and a member selected from the group consisting of zinc and zinc base alloys and encompassed at least in the main by and secured to said stainless steel member, said stainless steel member and said zinc or zinc base alloy being capable of alloying at the temperature of the sand core during casting for forming a disintegratable alloy during casting which becomes non-continuous for ready removal from the casting following casting thereof.

10. A self-eliminating core wire for use, and adapted to be embedded, in a sand core for reinforcing the same during casting of metal and readily removable from the metal casting following casting thereof comprising, a first continuous relatively rigid metallic member imparting sufiicient strength to the core wire adequately to reinforce the sand core and having a melting point higher than the temperature of the sand core during casting, said first metallic member being made from a metal selected from the group consisting of iron, steel, stainless steel, nickel, copper, molybdenum, manganese, tungsten, cobalt, beryllium, irridium, tantalum, and alloys containing at least one of said metals; and a second metallic member encompassed at least in the main by and secured to said first metallic member, said second metallic member being made of a metal selected from the group consisting of aluminum, zinc, silver, magnesium,

11 copper, and alloys containing at least one of said metals; said second metallic member being made from a metal selected from said last-mentioned group of metals, in relation to the metal selected from said first-mentioned group of metals, so

-as to have a melting point below the melting point of the metal from which said first metallic member is made and also below the temperature of the sand core during casting, said metals of said first and second metallic members being further so selected, in relation to each other, that alloying therebetween takes place and that said alloying occurs at the temperature of the sand core during casting and that the resulting alloy is molten, combustible, disintegratable or non-continuous for ready removal from the casting following the casting of the metal in said reinforced sand core.

11. A self-eliminating core wire in accordance with claim 10, wherein said first metallic member is made from nickel, and said second metallic member is made from aluminum and aluminum alloys.

12. A self-eliminating core wire in accordance with claim 10, wherein said first metallic member is made from nickel, and said second metallic member is made from zinc.

13. A self-eliminating core wire in accordance with claim 10, wherein said first metallic member has a cavity extending throughout the length thereof, and said second metallic member being continuous and located within the cavity of said first metallic member.

14. A self-eliminating core wire in accordance with claim 10, wherein said first metallic member is in the form of a sleeve, and said second metallic member is in the form of a continuous metallic wire secured within said sleeve.

15. A self-eliminating core wire in accordance with claim 10, wherein said first metallic member is in the form of a sheath of metal having a modulus of elasticity of at least 15x10 lbs./in.'- and a thickness between about 0.0001 and about 0.015 inch. 1 l

References Cited in the file of this patent UNITED STATES PATENTS I Number Name Date 408,508 Nash Aug. 6, 1889 978,847 Carlisle Dec. 20, 1910 1,336,449 Trunk Apr. 13, 1920 1,916,989 Rader July 4, 1933 1,946,451 Bailey Feb. 6, 1934 2,045,556 Almen June 23, 1936 2,305,555 Peters et al Dec. 15, 1942 2,373.405 Lowit Apr. 10, 1945 2,377,164 Lowit May 29, 1945 2,419,231 Schantz Apr. 22, 1947 2,434,392 Chace June 13, 1948 2,474,186 Marks June 21, 1949 FOREIGN PATENTS Number Country Date 25,457 Great Britain of 1907

Claims

10. A SELF-ELIMINATING CORE WIRE FOR USE, AND ADAPTED TO BE EMBEDDED, IN A SAND CORE FOR REINFORCING THE SAME DURING CASTING OF METAL AND READILY REMOVABLE FROM THE METAL CASTING FOLLOWING CASTING THEREOF COMPRISING, A FIRST CONTINUOUS RELATIVELY RIGID METALLIC MEMBER IMPARTING SUFFICIENT STRENGTH TO THE CORE WIRE ADEQUATELY TO REINFORCE THE SAND CORE AND HAVING A MELTING POINT HIGHER THAN THE TEMPERATURE OF THE SAND CORE DURING CASTING, SAID FIRST METALLIC MEMBER BEING MADE FROM A METAL SELECTED FROM THE GROUP CONSISTING OF IRON, STEEL, STAINLESS STEEL, NICKEL, COPPER, MOLYBDENUM, MANGANESE. TUNGSTEN, COBALT, BERYLLIUM, IRRIDIUM, TANTALUM, AND ALLOYS CONTAINING AT LEAST ONE OF SAID METALS; AND A SECOND METALLIC MEMBER ENCOMPASSED AT LEAST IN THE MAIN BY AND SECURED TO SAID FIRST METALLIC MEMBER, SAID SECOND METALLIC MEMBER BEING MADE OF A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, ZINC, SILVER, MAGNESIUM, COPPER, AND ALLOYS CONTAINING AT LEAST ONE OF SAID METALS; SAID SECOND METALLIC MEMBER BEING MADE FROM A METAL SELECTED FROM SAID LAST-MENTIONED GROUP OF METALS, IN RELATION TO THE METAL SELECTED FROM SAID FIRST-MENTIONED GROUP OF METALS, SO AS TO HAVE A MELTING POINT BELOW THE MELTING POINT OF THE METAL FROM WHICH SAID FIRST METALLIC MEMBER IS MADE AND ALSO BELOW THE TEMPERATURE OF THE SAND CORE DURING CASTING, SAID METALS OF SAID FIRST AND SECOND METALLIC MEMBERS BEING FURTHER SO SELECTED, IN RELATION TO EACH OTHER, THAT ALLOYING THEREBETWEEN TAKES PLACE AND THAT SAID ALLOYING OCCURS AT THE TEMPERATURE OF THE SAND CORE DURING CASTING AND THAT THE RESULTING ALLOYS IS MOLTEN, COMBUSTIBLE, DISINTEGRATABLE OR NON-CONTINUOUS FOR READY REMOVAL FROM THE CASTING FOLLOWING THE CASTING OF THE METAL IN SAID REINFORCED SAND CORE.