US1758488A - Mold - Google Patents

Description

May 13, 1930. w. M. WEIL 1,758,488

MOLD

Filed Feb. 11, 1929 INVENT Kam 7. BY

ATToRNEYs Patented May 13k, 1.930 l UNITED sTATEsPATENrfOFFICE WALTER M. WEILVOF CLEVELAND, OHIO, ASSIGNOB TO THE NATIONAL SMELTING COPANY,i OF CLEVELAND, OHIO, A CORPORATION OF OEIO MOLD . Application led February "1'1, 1929. Serial No.l 339,245.

This invention relates to the art of metal comprisin founding and more particularly to permaparticles.

nent molds and cores'therefor.

This application relateseto `a specic` emy 5 bodiment of the invention to which broader claims are directed in my copending -application filed of even date herewith, Serial No.

339,244, for Frangible molding material.

In the past castings of many metals, fer- 1o rous and nonferrous, have been formed in permanent, such as iron, molds in order to produce castings of relatively smooth surace, to obtain an increased rate of production, and to obtain the greatly increased mechanic'al properties ofi'metals cast in this manner. -The above advantages have been particularly noticeable in the case of light n `aluminum alloys, for example, in the manufacture of automotive pistons. While permanent, such as iron, cores have been employed in permanent mold' casting, in many cases it has been found desirable to employ rangible sand cores, partly because of the intricate nature of the interior of the castings. Certain diiculties, however, arise in the use of sand cores in this connection due to the relatively low heat absorbing powers An object of my inventionl is to provide of sand cores. Thus, the exterior/ of such.

rangible molding material of relatively high heat conductivity. Another object is to provide a frangible core particularly adapted for use in a (pe are to provi e a frangible core for use in the permanent mold casting of imetals of relatively high crystallization shrinkage, said core having-a relatively high heat conductivity. Another object is to provide a core Other objects will. be apparent to those skilled in the art from the disclosures herein made and from the accompanying drawings wherein:

Figure 1 is a vertical section through a permanent mold` having associated therewith a core contemplated by my invention, the view of the core being taken on line 1-1 of- Fig. 2;

Fig. 2 is an elevation of the core shown in Fig. l; and

Fi 3 is a. vertical sectional view ofa modi'- fied orm of core, the position of the core be# iIlng silibstantially the 'same as that shown in Y 1g.

'My invention contemplates in one of its forms a frangiblecore composed of metal particles such as grindings or borings. Such particles may be assembled into a core of the desired shape in a suitable core box by manual manipulation or by the use of mechanical pressure. If desired, a binder may be employed to cause the particles to adhere to each other, such as linseed oil, flour paste, or any suitable commercial core compound, the binderbeing preferably one which `will permit the core to become readily rangible after the casting operation.

In carrying out my invention I may form the .core by associating metal particles with sand, the relative proportions of which may bevaried to suit the particular conditions inhand. .A suitable binder such as described in the preceding paragraphy may be employed to cause'the core to retain a desired shape. The cores may, of course, be' baked, if desired. vIn forming cores comprisin metal particles and sand, the proportion o metal g a substantial amount of metallic particlesmay vary Within wide limits, for eX- exerted u on the interior of the casting. rmanent mold. Other objects p l tive heat conductivity in various portionsy of posed upon portions of the core, such the core surface or of the coregand outer mold cavity wall, a suitable coating ma be disceng vary to a considerable extent. however, for use wlth aluminum castings, I

being composed of any suitable material, for example,lime, together with silicate of soda and water. v

The composition of the metalparti'cles may Ordinarily,

find the use of iron, such as cast iron particles, to be very satisfactory, the melting point ofthe iron being, of course, considerably higher than that of the aluminum casting metal. Other metals may, of course, be employed or, in certain cases, a mixture of metals, for example, for use with aluminum castings the metal core particles may comprise also copper, brass, bronze or aluminum,

singly orin mixtures of two or more. Aluminum may in certain cases be employed because of its high heat conductivity and its non-tendency to adhere or weld to other zo particles of aluminum.

'The particular frangibility of core desired may be obtained by varying the nat-ure and size of the metal particles, the amount of sand, the amount and nature of core binder,

and the amount of pressure to which the core material is subjected in shaping the core.

In the drawings I have illustrated a permanent mold with which a core according to my invention may be employed. Upon the -base 1 are the mold sections 2, which may be( suitably disposed in molding position on the mold base bythe annular ring member 3 which extends upwardly above the normal upper surface of the base 1. Disposed on the base 1 within the annular ring member 3 is a core 4 formed according to my invention. The core is disposed in the desiredpositlon relative to thebase 1 and mold sections 2 by disposing the core within the annularlrrlng 40. member 3 and bymeans of a top portion of thecore which extends into the recess 5,1n the mold sections. In the present instance the mold and core shown are arranged to form a valve body casting 6 of substantially hollow cylindrical shape having a centrally disposed boss 7 within the casting wit struts 8 connecting saidboss to the side walls of the casting. The core 4 is shown as ro. vided with the core cavities 9 and 10 to orm 5 the boss 7 and struts 8 respectively. The

casting metal, such as an aluminum alloy, may be introduced into the mold in any suitable manner, such as for example through the sprue cavity -11 which may be arranged to introduce the casting metal to the top annular portion 12 of the casting 6.

In Fig. 3 I have shown a modified form of core which is additionally hollowed out to o provide the cavity 13 in order to lighten the core and to decrease the mass thereo Bythe combination of the permanent mold and my advantageous core it will be noted that the inside and outside of thehollow u;- casting 6 will be cooled at comparable de sired rates whereby the casting structure will be relatively uniform and ne-grained within and without, with the well understood advantages. Furthermore, the boss and strut of the casting 6 formed within the core 4 will be cooled at relatively rapid rates, whereby the metal of such boss and struts will be of substantially the same characteristics as the remainder of the casting. `By the'use of my advantageous frangible core, therefore, a casting having intricate internal surfaces may be readily formed in a permanent mold to provide a casting of uniform strength and structural characteristics.

It will be observed that Ihave provided frangible molding material of improved characteristics whereby casting metal may be chilled to a predetermined degree to obtain castings of desired physical characteristics.

It will thus be seen that I have provided a core of advantageous characteristics as kto heat conductivity whereby aluminum cast-` ings of substantially -uniform structure and mechanical properties may be formed, and whereby castings may be formed or chilled at the desired rate to impart desired physical characteristics. i

It will further be seen that I have provided lcations of said apparatus and procedure can n bemade without departing from my invention as defined in the appended claims.

What Iclaim is:

. 1. In combination, a permanent mold arranged to define the exterior of a casting and to chill relatively rapidly casting metal ldis- 'posed against'- said permanent mold, and a A frangible core including metal particles a1'- rangedto define interior portions of the casting, said core being arranged to hill relatively rapldly interior portions of said casting, whereby the interior and exterior portions o f said casting may be of comparatively unlform grain structure and physical properties;

' 2. In combination, metal mold sections and'- a frangible core including sand and metal particles, said mold sections and core being arranged to define a casting cavity, whereby casting metal disposed in said casting cavity may be caused to chill relatively uniformly to itform chilledcastings of improved properles.

, bination, metal mold sections and a l 3. A permanent mold foi-.casting alumi- A num alloys and the like comprising in commngible core of sand together-with iron particles composed of grindings, borings and the like, said p mold sections and core being arranged to dene a casting cavity, whereby aluminum alloy castings of Vuniform physical properties and fine grain structure may be obtained. l

In testimony whereof I aiiix m signature.

' WALTER WEIL.4

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