US1752040A - Mold - Google Patents

Description

March 25, 1930. TRAUT 1,752,040

MOLD

Filed April 2, 1928 INVENTOR.

ATTORNEY.

' Patented Mar. 25, 1930 nzzaa n. Timur, or

DETROIT, MICHIGAN I storm Application filed April 2,

This invention relates to molds and refers more particularly to improvements in molds used in foundries or used in general molding of metal articles.

55 it is an object of my invention to provide a mold of a permanent character as distinguished from molds commonly used in pres-- ent foundry practice. While my mold may be used to advantage in casting articles from 39 various metals, I will describe my invention for purposes of illustration in connection with metals of the nature of cast iron, steel, and the like. In this latter field my invention is of particular significance and importance in very materially reducing foundry costs, my mold being particularly adaptable to the molding of articles from cast iron, steel, and the like. The present foundry practice generally consists of casting articles in sand molds, the mold being'broken up after the casting of the metal. By reason of my invention it is not necessary to so break up the mold since my I mold is of a permanent character.

Many efforts have been made in the past to provide a mold of a permanent character, but to the best of my knowledge, there have been no successful and practical developments of permanentmolds prior to my invention. Some of the more vital requirements for molds used in foundry work are that the mold must stand up to the relatively high temperatures of the molten metal being cast, that the mold must be porous so as to vent freely, and thatthe mold must be capable of being handled during the casting operations without breakage. My invention consists essentially in the which not only meets the aforesaid requirements for molds but provides for many advantages over molds in general present day use. in carrying out my invention I form the mold preferably of carborundumor material of corresponding characteristics, which material is at present well known. Carborundum is formed in ahard solid mass from an initial granular form by firing at a temperature sufliciently high to develop a selfbinding effect as is well known. By employprovision of a material forming the mold 1928. Serial No. 266,602.

ing a pattern of the desired shape the carborundum may be formed by the generally customary process in accordance with the pattern to produce the desiredimold, which mold may be used in casting metallic articles there- 55 from as aforesaid. Such a mold when used for casting iron, steel, and the like will satisfactorily stand up to the temperatures now generally used. Furthermore my mold is highly porous and is self venting, eliminatso ing moisture and gas formations during the casting operation. My mold further reduces the possibility of cold shuts, run-outs, scabhing, and hard spots in the casting, the mold afiording rapid uniform cooling and venting 65 for the casting. My mold is stronger than customary molds and insures uniform castings, thereby substantially eleminating casting strains due to the weight of the metal being cast and permitting the casting to be 70 made with less clearance. This latter feature is very important, not only because of the resulting uniformity in the castings and saving in metal, but in materially reducing the cost of machining the casting. Thus by molding closer to. the desired finish than is heretofore possible, a corresponding decrease is effected in the amount of material required to be machined in order to bring the casting to the ultimate desired dimensions. The nature of my mold is such that greater uniformity is obtained than is possible in the customary sand mold. Since my mold is of a permanent character there is no possibility of dirt or portions of the mold itself being carried along into the mold with the molten metal. I have also discovered that the metal may be poured at a considerably lower temperature with my mold than is possible with ordinary sand molds, effecting a. saving in the operation of the crucible.

Further objects and advantagesof'my invention will appear from the following illustrative description and from the appended claims.

In the drawings, I

Fig. l is a sectional elevation view longitudinally through a mold illustrating my invention, 100

Fig. 2 is a sectional View transversely of the mold along 2;2 of Fig. 1, and

Fig. 3 is a section of a mold portion illustrating a modified'detail of construction.

Referring to the drawings reference character A represents a mold for casting a simple article it being understood that the shape of the mold is varied to correspond with the article desired to be cast. For simplicity of illustrating my invention the mold illustrated is constructed for casting a cylindrical article. The mold A is construct ed of a cope 10 and drag 11 each preferably being formed of carborundum or material having generally similar characteristics. In forming the cope and drag I prefer to provide each with a main body portion of relatively coarse carborundum which 'is highly porous, the cope and drag being faced with a molding lining 12 of relatively fine carborundum. The lining 12 will present a very smooth molding surface having the desired venting characteristics, the backing or main body portion having a greater venting characteristic. I prefer to fire the backing and lining together so as to provide a unit construction for the cope and the drag although, if preferred, the lining may be fired separately and fitted into the backing, in which in stance the lining would be more readily replaceable to provide for minor changes in the casting and for damage to the lining of the mold.- If desired the carborundum mold may be fashioned from a body of the carborundum material, although the nature of carborundum is such that it cannot be. readily worked, once it is fired by the usual process into a solid mass. I may also dispense with the lining 12 and form the mold portions of the same material throughout which I have foundto be entirely satisfactory. The provision of the lining 12 is' a further refinement of my invention which'I-regard as desirable althoughnot indispensable.

An importanfi'feature of my invention resides in the elimination of much or all of the sand coring or othernon-permanent coring now commonly used in foundry practice, by forming the cores from the same material. In this manner the cores are also of a permanent character and if desired the cores' may be formed with a lining corresponding to the lining 12 of the cope 10 and drag 11. In

.some types, of molds the nature of the core is such that it cannot be withdrawn after the casting operation and in casting articles of this character I contemplateusing the usual fore set forth. Thus in .Figs. 1 and 2 the.

body portion of core 13: may be formed of relatively coarse carborundum of high porosity, a facing or lining 14 being of relatively fine carborundum corresponding to the lining 12.

Provision is made for ouring the molten metal into the mold, pre erably by the provision of a pouring basin and gate formed of the material used for the mold proper. Thus the pouring gate is preferably formed in halves 15, 16 a gate 17 conducting the molten metal from a pouring basin 18 to the mold cavity or cavities 19 for molding the article. I

The gate portions 15, 16 are preferably formed separate from the cope and drag with a draft at 20 permitting removal of the cope after casting and then separation of the gate portions for clearing the metal incidentally cast in the gate passage 17 leading to the the mold the core 13 and gate portions 15,16 may be positioned on the drag 11, and then the cope 10 placed in position for .the pouring operation. To facilitate positionin and locating the cope on the drag any we 1 known positioning means may be provided as the where the. articles require extensive core, work, such as in cylinder block castlngs for the motor vehicleengine industry, I may reinforce the body portions of the cope and drag by providing metal reinforcing "rods 22 such as used in concrete reinforcing work. In carrying out my invention it may be found desirable under some circumstances to make the cope'and drag in sections whereby substitute sections may be used in case of minor ca ting clfanges or damage to the mold, thus avoiding replacement of an entire mold. Or it will sometimes be more expedient to construct the mold lining 12 in sections permitting substitution of corresponding sections for casting changes. Thus parts of the mold subject to excessive wear may be remold cavities 19. Similarly in assembling newed without replacing the entire mold and where the lining 12 is used, such lining may be replaced as required without scrapping the body portion of the mold. Fig. 3 illustrates a slightlymodified mold, the drag only being shown at 11. y In this view the lining 12 of the fine refractory material is made in sections 23, 24, 25 readily removable from the body portion of the mold'for replacement to take care of casting changes, damage to themold and the like.

My moldwill permit casting of sharp corl ners without causing crystallization, the metal readily laying up to the inold and readily venting. p

In practice I find it desirable to apply a coating to the interior of the mold and to the cores pr or to assembling. the mold for practical for ordinary commercial foundry casting in order to prevent any tendency for the metal to adhere to the mold, and to facilitate easy removal of the casting from the mold. In practice I find that ordinary lamp black is desirable for this purpose. Y

" While I have'described my mold as being formed of carborundum or of material having generally similar characteristics I desire .to point out that it is not my intentionto limit the scope of my invention to any par-. ticular material. Prior to my invention there is no teaching in the art of a mold of a permanent nature which is satisfactory and work and I consider my invention to be of a correspondingly broad scope. In my experiments embodying my invention, I have discovered that carborundurm will fulfill the objects of my invention and provide a permanent mold entirely satisfactory for commercial foundry practice. By reason of my invention I have provided a mold-and core of a permanent nature, whereby large numbers of articles may be cast therefrom.

What I claim as my invention is:

1. A mold of a permanent nature for use in casting articles from-molten metal, said mold having a body portion of relatively coarse heat resisting porous material and a separable lining portion of relatively fine heat resisting porous material.

2. A mold of a permanent nature for use in casting articles from molten metal, said mold having a porous body portion and a porus facing, said facing being removable relatively to said body portion.

3. A mold of a permanent nature for use in casting articles from molten metal, said mold being porous,-and reinforcing means for the mold.

4. A mold of. a permanent nature for'use in casting articles from molten metal, said mold being formed of a refractory material reinforced internally.

-5. A mold of a permanent nature for use in casting articles from molten metal, said mold having a porous bodyportion and a porous facing, said facing being removable relatively to said body portion, said facing being formed of a plurality of relatively removable sections.

6. A mold of a permanent nature for use in casting articles from molten metal, said mold being formed of a rigid refractory m aterial permanently reinforced interiorly.

7. A mold of a permanent nature for use in casting articles from molten metal, said mold being formed of a refractory material permanently reinforced interiorly, anda removable porous facing for said mold.

8. A mold of a permanent nature for use in casting articles from molten metal, said mold having a porous body portion and a porous facing both formed of carborundum,

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