US3264697A

US3264697A - Method of forming composite metal bodies

Info

Publication number: US3264697A
Application number: US273615A
Authority: US
Inventors: David E Price; Herbert J Wagner
Original assignee: Roehr Products Co Inc
Current assignee: Roehr Products Co Inc
Priority date: 1963-04-17
Filing date: 1963-04-17
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09

Description

Aug. 9, 1966 E. PRICE ETAL. 3,264,697

METHOD OF FORMING COMPOSITE METAL BODIES Filed Apri 17, 1963 I. WW, w, +77% 614.

United States Patent David E. Price, R hr bus, Ohio, assignors, by mesne assignments, to Products Co., Inc., a corporation of Delaware Filed Apr. 17, 1963, Ser. No. 273,615 Claims. (Cl. 22204) This invention relates to the forming of metal composites and in particular to the forming of metal composites wherein a plurality of elongated elements are integrally associated with a surrounding matrix;

In certain applications such as in the provision of reactor rods in a suitable non-radioactive matrix medium, it is desirable to obtain a positive metallurgical bond between the matrix material and the rods at the interface therebetween. In certain other applications such as in the preparing of billets for use in wire drawing, wire rolling, etc., it is deemed desirable to not only provide such a positive bond between the matrix material and the rods from which the wires are to be formed but also to effectively preclude the attacking of the rod material by the matrix material, particularly where elevated temperatures are employed in one or more of the process steps.

The present invention comprehends an improved meth- 0d of forming such a billet or composite body wherein a matrix is effectively positively bonded to the embedded elongated elements or rods. Thus, a principal feature of the present invention is the provision of a new and improved method of forming composite bodies.

Another feature of the invention is the provision of such a method wherein a matrix material is effectively positively bonded to elongated elements embedded therein.

A further feature of the invention is the provision of such a method wherein the matrix material is eifectively prevented from attacking the rod material notwithstanding the presence of high temperature conditions during one or more portions of the process steps.

A still further feature of the invention is the provision of such a method wherein the matrix material is caused to flow rapidly and uniformly throughout the space in which the rods are disposed, with the spacing between the rods being effectively minimized.

A yet further feature of the invention is the provision of such a method wherein the matrix material is introduced in molten state to form a casting about the rods, the temperature of the matrix material and the rods at the time of casting being preselected as a function of the heat capacity and dimensions of the rods and mold and the heat capacity and heat of fusion of the matrix material to cause substantially instantaneous solidification of a thin layer of the matrix material on the surface of the rods when contacted with the molten matrix material and thereby preclude attacking of the rods by the molten matrix material.

Still another feature of the invention is the provision of such a method further including the step of coating the rods with a thin layer of bonding metal.

A yet further feature of the invention is the provision of such a method further including the step of coating the rods with a material precluding attacking of the rods by the matrix material.

A yet further feature of the invention is the provision of such a method wherein the coating material serves both as a bonding material and an attack-preventing material.

Other features and advantages of the invention will be apparent in the following description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a diametric section of a casting appaice ratus and cage structure therein as in a first step of the disclosed method of forming a composite body;

FIGURE 2 is a transverse section thereof taken substantially along the line 2-2 of FIGURE 1; and

FIGURE 3 is a side elevation of a composite body, or billet produced as by the disclosed method.

In the exemplary embodiment of the invention as disclosed in the drawing, a composite metal body, generally designated 10, is shown to comprise a plurality of elongated elements 11 embedded in a matrix 12. The invention comprehends a forming of the body 10 with the elongated elements 11 firmly and positively bonded to the matrix material uniformly along their entire lengths. The invention further comprehends the provision of the body 10 wherein the matrix material is cast about the elongated elements 11 with attack of the elements 11 by the matrix material during the casting operation being effectively precluded.

Reference now being had more specifically to FIGURE 1 of the drawing, the invention comprehends firstlly arranging a plurality of the elongated elements 11 in spaced parallel relationship in the form of a cage generally designated 13. For retaining the elongated elements in the cage, a pair of

end plates

14 and 15 may be provided being suitably perforated to receive the opposite ends of the elongated elements. At least one of the Plates may be suitably perforated to permit free movement of the end of the elongated elements therein to accommolate expansion and contraction of the elongated elements during the casting process.

In illustrating the invention, it will be assumed that the elongated elements 11 comprise stainless steel rods or wires such as for use in forming small diameter filaments by suitable subsequent forming of the resultant composite body, or billet, 10. As one example, the rods 11 may be formed of A181 Type 304 stainless steel. As shown in FIGURE 2, the rods are disposed herein in a uniform distribution being generally equispaced and arranged in a symmetrical pattern. The spacing between the rods is effectively minimized to permit the forming of the billet with a minimum amount of matrix material.

The assembled cage 13 is next installed in a suitable mold 16 having a casting chamber, or cavity 1611. As shown in FIGURE 1, the top end plate 14 is provided with opposed outwardly projecting lugs 14a carrying upstanding stops 14b. Herein four lugs and stops are provided spaced apart. The cage and mold are then heated by suitable means to a preselected casting temperature, herein illustratively approximately 1850 F. A vacuum is drawn on the chamber 16a through a suitable outlet 17 during the heating process by suitable means (not shown) to effectively preclude attack of the stainless steel elements 11 during the heating step. If desired, the

vacuum may be drawn on the chamber 16a prior to the heating step and the mold then scaled as by welding. If such prior evacuation is employed elevated temperature outgassing may be used. Alternatively, an inert gas, such as argon, may be introduced into the chamber 16a during the heating process to preclude the corrosion of the elements 11. It is preferred, however, that at the time of introduction of the matrix material into the cavity 164: that a vacuum condition be obtained therein both for facilitating the drawing of the matrix material into the cage structure and to assure the absence of gases in the cavity which may form bubbles, and the like, on the elements 11 during the casting process.

As seen in FIGURE 1, an inlet 18 is provided in the mold 16 which is normally closed by a plug 19 sealed to the top wall 20 of the mold by means such as brazing 21. As shown in FIGURE 1, the top wall 20 is spaced slightly above the stops 14b. The mold may further include an matrix material then runs down into the mold cavity 16a and through the interstices 25 between the elements 11 to completely fill'the interstices and bind itself firmly and positively to the elements 11 along their entire lengths.

The invention comprehends the heating of the mold and cage to a temperature determined by the heat capacity and dimensions of the rods and mold, and the heat capacity and the heat of fusion of the matrix material, said temperature being such that when the matrix material contacts the elements 11, the portion thereof immediately surrounding the elements substantially immediately solidifies to form a thin coating effectively preventing attacking of the stainless steel elements by the molten matrix material. However, the layer of solidified matrix material coating each element 11 issufliciently thin to preclude bridging of the interstices 25 between the elements 11 which might otherwise preclude uniform distribution of the matrix material throughout the cage. The temperature to which the matrix material is heated is preselected ;as a function of the heat absorbing'characteristics of the elements 11 and the thermodyamic characteristics of'the matrix material including the specific heat characteristic thereof and the heat of fusion thereof.- Further, where the mold 16 is .formed of a conductive ma-.

terial, such'as metal, the heat absorbing characteristics thereof are considered in determining the temperature at which the matrix material should be delivered to the cavity 16a. Obviously, however, the mold may be formed of an insulating material so as to avoid heat loss therethrough and permit the rods to absorb substantially all of the heat energy from the molten matrix material to effect the solidification thereof.

As indicated briefly above, a quantity of nickel maybe provided in the matrix'material. The specific quantity of nickel may be preselected to adjust the working tem perature range of the matrix material to permit subsequent working of the billet without reliquefying of the matrix material. Illustratively, the matrix material may comprise a mixture of 80% copper and 20% nickel 'where the elements 11 comprise AISI Type 304 stainless steel. To further assure a positive bond between the matrix material and the elements 11, the elements may be firstly coated with a layer 26 of a bonding metal, such as nickel, which has the property of dissolving both in'the stainless steel and in the copper. Illustratively, a coating approximately .001 inchthick may be applied. Such a coating provides not only .an improved bond between the matrix material and the elementmaterial butalso provides an effective corrosion resisting barrier further protecting the stainless steel from attack by the copper matrix material.

The above disclosed process provides an improved billet 10 wherein the elements or rods 11 are intimately and uniformly bonded throughout their lengths to the matrix material. Thus, the billet 10 comprises an improved billet for use in subsequent constricting operations, such as hot rolling operations wherein the billet is reduced in diameter to correspondingly reduce the diameter of the elements 11. Such constriction may be effected in successive steps until the elements 11 are reduced in diameter to one mile or less. bond between the elements 11 and the matrix material, discontinuities in the resultant small diameter filaments may be effectively minimized.

While we have shown and described one embodiment of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the con- By providing the improved struction and arrangement'may be. made without departing from-the spirit andscope'ofthe invention as defined in the appended claims.

We claim:

1. The method of forming a composite metal body, comprising the steps of: disposing a plurality of elongated elements in laterally spaced parallel relationship to define a cage; placingv said cage .in a mold cavity; drawing a vacuum in saidcavity; heating said cage to a preselected preheat temperature; heating a quantity of matrix material, to 'a temperature preselected as a function of the heatcapacityof said elements andthe heat capacity and heat of 1. fusion ofv said matrix material to cause substantially instantaneous solidification of a thin layer of said matrixmaterialion' the surface of the elements when contacted therewith;; and: introducing the heated matrix material into the cavity to cast the matrix material about .the elongated elements of said .cage .to define a billetof said elements metallurgically bonded to said matrix material.

2. A method of forming a composite metalbody,'corn-: prising the steps-of: providing a plurality of elongated elements witha coating of bonding material; disposing the plurality of ;coated elongated elements; in laterally spaced .parallel relationship to define a cage; placing said cage in a mold cavity; drawing a vacuum in said cavity; heating said cage to a preselectedpreheat temperature; heating .a :quantity of matrix material to atemperature pr-eseletcedas a function of the heat: capacity of said elements and .the heat capacity and heat of fusion of said matrix material to cause substantially instantaneous solidification of a thin layer of said matrix materialon the surface vof the elements when contacted therewith; and introducing theheated matrix material into the cavity to cast the matrix material about the elongated elements of said cage to define a billet of said-elements metallurgically bonded to saidmatrix material.

3. The method of claim 2 wherein said bonding mate-,

rial comprises a material soluble in the material of which the elements are formed and in the matrix material.

4. The method of claim 2 wherein said bonding mate'-.

rial comprises a material precluding attacking of 'said elements by said matrix materiaLi 5.- The method of claim 2 wherein said elements are formed of stainless steel, said matrix comprises a cuprous' material, and=said bonding material comprises nickel.

6.. The method of claim 2 wherein said elements are formed of stainless steel, said matrix comprises a cuprous material, and saidbonding material comprises; nickel deposited on saidelements in a coating approximately .001" deep.

7. A method of forming a composite metal body, comprising the steps .of: :disposing a plurality of elongated elements in laterally. spaced parallel relationship to define acage; placingsaid cage in a mold cavity; heating said cage to a preselected preheat temperature while preventing attacking. cf-the elementsby air in'said cavity; heating a quantityof matrix material to a temperature preselected as a function of the heat capacity of said elements and the heat capacity and heat of fusion of said matrix material to cause substantially instantaneous solidification of a thin layer'of said matrix material on the surface of the elements when contactedtherewith; andintroducingthe heated matrix material into the cavity to cast the matrix material about the elongated elements of said cage to define ta billet. of said. elements .metallurgically bonded to said matrix material.

8. A composite metal body formed-by .the steps of:

disposing a plurality of elongated elements in laterally.

spaced parallel'relationship todefine a cage; placing said cage in a mold cavity; drawing a vacuum in said cavity; heating said cage to a preselected .preheattemperature;

heating a quantity of matrix material to a'temperature preselected as a function of the heatcapacity of aid elements and the heat capacity and heat of fusion of said matrix material to cause substantially instantaneous solidification of a thin layer of said matrix material on the surface of the elements when contacted therewith; and introducing the heated matrix material into the cavity to cast the matrix material about the elongated elements of said cage to define a billet of said elements metallurgically bonded to said matrix material.

9. A composite metal body formed by the steps of: disposing a plurality of elongated elements in laterally spaced parallel relationship to define a cage; placing said cage in a mold cavity; drawing a vacuum in said cavity; heating said cage to a preselected preheat temperature; heating a quantity of matrix material to a temperature preselected as a function of the heat capacity and dimensions of said elements and the walls of the mold cavity, and the heat capacity and heat of fusion of said matrix material to cause substantially instantaneous solidification of a thin layer of said matrix material on the surface of the elements when contacted therewith; and introducing the heated matrix material into the cavity to cast the matrix material about the elongated elements of said cage to define a billet of said elements metallurgically bonded to said matrix material.

10. The method of forming a composite metal body, comprising the steps of: disposing a plurality of elongated elements in laterally spaced parallel relationship to define a cage; placing said cage in a mold cavity; heating said cage to a preselected preheat temperature; heating a quantity of matrix material to a temperature preselected as a function of the heat capacity of said elements and the heat capacity and heat of fusion of said matrix material to cause substantially instantaneous solidifica- 6 tion of a thin layer of said matrix material on the surface of the elements when contacted therewith; and introducing the heated matrix material into the cavity to cast the matrix material about the elongated elements of said cage to define a billet of said elements metallurgically bonded to said matrix material.

References Cited by the Examiner UNITED STATES PATENTS 929,777 8/1909 Monnot 22204 972,630 10/ 1910 Monnot 22204 1,125,163 1/1915 Page 22203 1,760,583 5/ 1930 Devers 22202 2,193,246 3/ 1940 Chace 22204 2,398,529 4/1946 Holmguist 22--204 2,453,772 11/ 1948 Whitfield 22204 2,543,936 3/ 1951 Reynolds 22204 2,611,163 9/ 1952 Schaefer et al. 22203 2,708,641 5/ 1955 Cape 22204 2,904,861 9/ 1959 Morgenstern 22-214 OTHER REFERENCES Composite Castings, Metal Industry, July 10, 1953, pp. 23-26 relied on.

I. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, MICHAEL V. BRINDISI,

Examiners.

R. D. BALDWIN, Assistant Examiner.

Claims

1. THE METHOD OF FORMING A COMPOSITE METAL BODY, COMPRISING THE STEPS OF: DISPOSING A PLURALITY OF ELONGATED ELEMENTS IN LATERALLY SPACED PARALLEL RELATIONSHIP TO DEFINE A CAGE; PLACING SAID CAGE IN A MOLD CAVITY; DRAWING A VACUUM IN SAID CAVITY; HEATING SAID CAGE TO A PRESELECTED PREHEAT TEMPERATURE; HEATING A QUANTITY OF MATRIX MATERIAL TO A TEMPERATURE; PRESELECTED AS A FUNCTION OF THE HEAT CAPACITY OF SAID ELEMENTS AND THE HEAT CAPACITY AND HEAT OF FUSION OF SAID MATRIX MATERIAL TO CAUSE SUBSTANTIALLY INSTANTANEOUS SOLIDIFICATION OF A THIN LAYER OF SAID MATRIX MATERIAL ON THE SURFACE OF THE ELEMENTS WHEN CONTACTED THEREWITH; AND INTRODUCING THE HEATED MATRIX MATERIAL INTO THE CAVITY TO CAST THE MATRIX MATERIAL ABOUT THE ELONGATED ELEMENTS OF SAID CAGE TO DEFINE A BILLET OF SAID ELEMENTS METALLURGICALLY BONDED TO SAID MATRIX MATERIAL.