USRE15990E - Method of casting - Google Patents

Description

METHOD oF CASTNG Feb. 1925.

' ,Reissue Fes, 1925.

HARRY a. SCHWARTZ,

PATENT OFFICE.

or CLEVELAND, oHI'o. y

METHOD -OE CASTING.

Original No. 1,428,987, dated-September 12, 1922, Serial No. 475,968, led June 8, 1921.

reissue filed August 22, 1324.v Serial No. 738,108.

To all whom t may concern.'

Beit known that I, HARRY A. SCHWARTZ, a citizen of the United States, formerly a resident of Defiance, in the county of Dei fiance in the State of Chio,- and now lresiding at Cleveland, in theconnty of Cuya- 'hogaand the State of'Ohio, have invented a new and ImprovedMethod of Casting, of

which the following is'y a full, clear, and' that `uniform cast-ings may be made inv permanent molds lwithout material or injurious deterioration of the mold itself.` 'i Iam, of course, aware that it is old in the art of casting to cast in permanent molds -and it isalso oldto chill or cool molds, but I believe that I am the first to cast in molds,

where the mold is maintained within a constant range of temperature.

, The art of casting in permanent molds has been developed extensively in the low melt- 30 v ing alloy `metal field by the die casting process; that is, `forming castings of alloy metal in metal dies by placing the metal in the dies under pressure. The-cause of the -development of this particular iield is due to the fact that alloys of comparatively low .melting temperature are used, the dies or -molds not being subjected to the comparatively extreme temperatures which are necessary inthe metal group, s uch as iron, etc.

When permanent molds, such as hereto- Afore used, are subjected. to extreme heat and -allowed to cool repeatedly, they will deteriorate to "a more or less rapid extent'. Also after pouring for a time, the molds become' very hot, so that castings cannot be made in as vfrequent intervals as when the molds were cooler. j

Wit-h ordinary permanent molds, when the cast iron is poured in the heat :from the molten metal is extracted very quickly depending upon thesize of the casting made.

Segregation in this way is largely prevented, the metal'V setting so quickly that segregation cannot take place to a. large extent,

improvements in' Aprocess emphasis is particularly lai u Application for but permanent molds such as ordinarily made d o not have any control of temperature but rely7 solely upon a reduction of temperature or a. carrying away of the heat units by radiation or chilling. The problem, therefore, of casting metals having a high melting point in permanent molds resolves itself into the question of first taking away from the mold the heat that it has taken from the casting made in it until the casting is set, and then maintaining a compara-tively uniform temperature for a desire-d length of time between pourings vand inally allowing the casting separated from the mold to cool as gradually as may be desired, and I can accomplish this purpose in molds of the same metal as the castings without danger in' any way of injuring the mold but 0n the other hand permitting a repeated use of the mold.

Furthermore, the physical properties of the metal, such` for exam le as iron castings, are improved considerably when cast in permanent molds. When ca st iron sets from the molten stage, the'elements which make up the cast iron composition tend to segregate to a large extent. If this segregation is largely prevented the physical properties are improved, and it is one purpose of my invention to provide a method 'of casting wherebyv the temperature of the mold is controlled and stablized so that the segregation can be prevented in so far as it is desirable to do so.

In casting metals having a relatively hi h melting point, for example; above 1000 egrees Fahrenheit in permanent molds, the following tiveY factors govern to a large extent the process:

` l. Temperature control of the molten iron or other metal at the pouring.

2. Controlling the molten stream, as to cross-section and How when' entering the mold.

3. Maintaining the mold at an even and constant temperature range.

4. Controlling the ejection of the casting on its completion.

5. Preserving the physical condition of the mold.

All of these factors must be considered to produce the best results, but in the resent n the third element, .maintaining the mol v at 'an even and constant temperature range,

1 and the fifth element preserving the physiy cal condition o'fpthe mold.

the output or effectiveness ofthe mold oper- A further object is to provide method of the character .xstatedv whlch not only 'results in the making of superior castings but which lengthens the life of themold and increases f 'of .temperature control ofl the' inold and means and steps in the operation of controlling the temperature of the mold during hereinafter described and-pointed out in the l claims.

In the accompanying drawings l Figure 1 is a view showing more or less dia-grammatically anA apparatus in 'which my improved method of casting can be carried out. v Figure 2 is-a view in longitudinal section through the `mold.

I would have it 'under-stood Vthat this inlvention is not limited to any particular form i of mold or mold support, although itis to be understood that the mold will be preferably of metal, comprising two or more ' sections 1 and 2 having a mold space 3 between them` in which the casting 4 is formed. The mold sections 1 and 2 are hollow orm ing fluid chambers 5 and these Huid cham; bers maybe arranged and shaped in -any desired way to give vthejbest results. i

In carrying out myimproved method I preferably employ a storage tank ,orreservoir,6, from which the fluid is l' forced by means of a pump 7 through al ipe 8 and branch pipes 9 and 10 -into the uid chami bers 5 of theupper and lower mold sections. In this pipe 8 and -in the branch pipes 9 and 10 I provide , manuallyoperated valves 11, 12 and 13 respectively, so that the low Aof fluid; through the mold sections canv controlled.

14 represents a refrigerating device of any approved constructiom. and I do not wish to be limited to the arrangement of tank shown and may employ any refrigerating device desired. Branch outlet pipes-'15` and 16 communicate with the'uppe'r and lower mold sections 1 and -2 respectivelyand discharge into a pipe 17 communicating with the lcondenser, ,tank 14 and api ev 18 connects the condenser tankvwith -t e sto-rage tank 6. so that a circulation may be maintained or cut oi asldesired.

While I have illustrated in the drawings as a cooling -or temperature controlling 'medium a li uid, it is o bvios kthat 'I' may .ein loy any uideithergas or liquid which w11 perform the functions intended. I do not claim, however, the 'use of water as a temperature controlling medium or any uid ture of water, or that 'does not possess the thermal properties of comparatively ready heatrabsorption yand lheatconductiorr wellknown example of a fluid having the desired'characteristio is mineral oil,` and I expressly disclaim the use of fluida-such as water.

It is to be understood that the system is preferably ull of the sothat when the :pump 7 is. operated the fluid will be caused as the position of the valves 11, 12 and 13 will permit. .In carrying out the method the molten metal is poured into the mold, and when 4po-uring large castings it is preferable at the initial pouring to have the valves 11, 12v

I p 'vto circulate through the system as rapidly the casting operationsas will be more fully and 13 -Wide openvr so that a maximum vflow of the temperaturefcontrolling iiuid will be had. through the chambers 5 of the mold 'to cool 'the casting and l rapidly carry away the heatV in excess of the predetermined -mold temperature.

Q'This rapid cooling accomplishes the purpose i of largely preventingF segregation of the f elements of the casting. Whenpouring a run of small castings the flow is cut down lay-partially closing the valves and may be cut down as 4much as desired to maintain the temperature ofv the mold, or the 'iow may be regulated to permit a. slow decline in slowly or as quickly as desired and to maintemperature thereby to cool the casting as` tain the vmold at a certain temperature for a. period of time between pourings and then fcool it to' remove the -heat in excess of the predetermined temperature added by earch pouring,- all of which temperature regulationi is under the control of the operator I the operation' sc thatf the temperature can be maintained or decreased .as desired and always under thecontrol of the operator.

It is to be understood that by temperature regulation I not only include by such a i term a reducing of temperature, but more particularlya method whereby the mold maybe maintained at a relatively constant temperature for the Adesired length of time for a run of castings.

In carrying out my unproved methodoli casting in permanent molds whereby the temperature of the mold -is regulated and stabilized, I employ aclosed temperaturecontrolling fluid circuit with means in the I circuit for establishing a desiredt'emperaturefor the Huid 'andgwith means in the circuit for controlling the amount of Huid in transit. Fig. 1 illustrates clearly the closed circuit; 14 represents the means or establishing a desired temperature for the trol I am convinced that no propertem" perature regulation can be had in a run of castings in a permanent mold. In carry.

ing out-my improved method of such regulation I am enabledto reduce the temperature of the mold and the castings `as' rapidly as desired, maintain the mold vtemperature uniform Within the'predetermined range or gradually decrease the -temperatureto carry away excess heat as may be desired, so that there may be in truth and in fact a real temperature regulation.

.I expressly disclaim, however, the maintenance of any mold temperature range which includes the decalescence point of the mold material, or which is ator below the boiling point of Water. The pre-` determined tempera'ture range" Within the given limits depends on the material of the mold,.the heat of the molten metalthe size and character ofthe castings, and the interval between successive pourings. For example, in makinga smallthin iron casting in a permanent ferrousmold satisfactory results have been obtained by stabilizing the temperature during a run of 'cast-3 ings made`- at'about one minute-intervals at approximately degrees-Fahrenheit' Within a constant` range ofapproximately 10() degrees Fahrenheit from a mean tempera-ture. It will be understood', of course,

that the mean temperature determined for the mold and the fluctuations therefrom may be raised lor lowered yin practice depending on the character of the mold and the casting or both.-

The last step in the method'where itis desired to obtain smooth inished castings Without machining, is to injectthe castings `into an asbestos powder or treat the same in any Well known manner which Will prevent surface oxidation.

It is obvious that the invention is not limited to the particular apparatus above described, as I desire to cover broadly the idea of temperature regulation for molds of the type set forth, whereby castings are formed on a" productive scale without substantial or in urious" deterioration' of the permanent moi provement in the art, and'furthermore, I believe t-he'entire operation of casting in d, which I believe is an im,

accordance With my method results in" veconomy and inbetter'results to the trade. Having'thus described my. invention I claim :l l ,A 1

l. The herein described method of 'casting, consisting in intlaiducing molten metal into 'a mold, and'maintaining the mold With'- in a constant' range of temperature.

2. The herein'described method .of casting, consisting in providing a pair of permanent mold members, moltenv metal betweenl the mold members, and maintainingthe mold Within a'constant range of temperature. l 3. The herein describedprocess of casting,' consisting in casting molten metal in a permanent mold of the same metal vas the" casting,vsaid mold members having chambers therein, and-during the process of cooling the casting 'in the mold, maintaining the moldvvithin 'a constant range of temperature, bythe movement .of the fluid through the chambers.

introducing sol Y 4. 'The herein-described method of casting', consisting in providing a pair of mold members .having fluid vcpshambers therein, in-

troducing molten metal between the mold members, causing arcirculationof a cooling uid through s aid'chamber's,` and con'- trolling the flow of said `fluid to maintain thevmold Within a constant range of temperature.

5. The herein described method of casting, consisting in'casting in a permanent lnold, Aand during the' time the,.casting is in the Ymold and after the-casting is ejected from the mold, maintaining a constant 'range jof temperature vof the mold- '6. The hereinv described method of casting metals having a relatively high melting point- Which consistsin repeatedly introducing molten metal into a'permanent mold and separating castings therefrom and maintaining the mold during a run of castings ivithin a constant range of temperature by circulatinga non-aqueous, heat absorbing and heat-conducting liquid near the casting cavity.

7. The herein described method of casting metals having a relatively high melting point, which consists .in repeatedly introducing molten metal into a permanent mold and separating the castings therefrom and maintaining the mold during a run of castings within a constant range of temperature by circulating oil through the mold.-

8. The herein described method of casting metals having a relatively' high melting point, which consists in. pouring vthe molten metal into a permanent mold, and maintaining the mold within a constant range of temperature by circulating a non-aqueous, temperature-controlling liquid near the casting cavity. and regulating the'temperatureof the liquid outside of the mold.

-determined range of mold temperature above the boiling point of Water and below the point at which said mold deteriorates.

10. The method of casting metals having a relatively high melting point, which consists intransferring heat initially received vby the mold from the cast metal by circulatmg a non-aqueous, heat-absorbing fluid in he mold near the casting cavity, and con- ,rolling the flow of the fluid to stabilize and maintain the temperature of the mold during the casting period within a predeterminedr range not .including the decalescent temperature of the metal and above the boiling point. of Water.

11. The ymethodof casting materials having a relatively high melting point in permanent molds, which consists in stabilizing the mold temperature by passing a regulated quantity of .non-aqueous, temperaturecontrolling fluid near the casting cavity and varying the quantity of luid to counteract the tendencyI of the mold temperature to rise or fall -above or.v below the predetermined temperaturel range.- Y l 12. The herein described method of casting iron in a permanent ferrous mold which comprises introducing metal i'nto the mold and circulating oil near the casting cavity and varying the rate of circulationin accordance with the amount of heat passed to the mold to maint-air. the temperatureof the mold within a given range during a run of castings.

,13. The herein described method of casting iron in a permanent ferrous mold having a chamber in proximity to the casting cavity, which comprises circulating oil' through said chamber and varying the rate of circulation i'n'accordance with the amount ing which consists in successively pouring.

molten material into a permanent ferrous mold and separating the castings therefrom,

and during and between the time that the 'I castings are in the mold maintaining the same Wit-hin a constant range of temperature having fluctuations of not more than 100o F'. above or below a predetermined fpoint, the range of temperature being above the boiling point of water and below the temperature at which the mold 'metal deteriorates.

15. The herein described method of serving the material of a permanent mold against deterioration which comprises keeping the temperature of the mold niaterial within a given range during casting operations and between successive casting operations.

16. The herein described method of preserving'the material of a permanent mold against deterioration which comprises circulating a non-aqueous fluid in contact therewith to keep the temperature of the mold material within a given range during casting operations.

17. The herein described method of preserving the material of a permanent mold against deterioration which consists in keeping the mold during the casting operation at such temperature that substantial molecular changes do not occur in the mold material. A

Signed at New York, in the county of New York and State of New York, this fifteenth day of August, A. D. 1924.

HARRY A. SCHWARTZ.

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