US1454064A - Process of casting metals - Google Patents

Description

of Toledo, Lucas Patented May 8, 1923.

PAT

OFFHCE.

HUBERT A. MYERS, OF TOLEDO, AND ARTEEMES D. STRAW, OF WAUSEON, OHIO, ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, TO THE HUBER! A. MYERS COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO. I

PROCESS CASTING METALS.

No Drawing.

To all whom it may concern:

Be it known that we, IlUm-urr A. MYERS and Amenities D. STRAW, citizens of the United States, and residents, respectively, County, Ohio, and Vauseon, Fulton County, Ohio, have made an invention appertaining to Processes of Castin Metals; and we do hereby declare the fol owing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

()ur invention relates to the art of casting metals in permanent molds, and it has for its object the rapid and economical pro duction of castings, uniformly superior in finish and quality.

It is a matter" of common knowledge that the casting of metal in cold metallic molds will produce hard, brittle castings and that a cold metallic mold will cause the metal to rapidly congeal'and crystallize locally,

and thus prevent any but the plain'est kind of castings from conforming to the matrix of the mold. Efforts have been made to avoid these difiiculties or objections by heating the mold, but with the result that the castings would adhere or stick to the surface of the mold and prevent delivery of the castings therefrom. Attempts have also been made to prevent adherence of the castings to the mold, whether hot or cold, by coating the molding surface with various materials, such as graphite, aluminum paint, I

and similar surfacing materials, but these have not proven satisfactory or efficient in practice. ()ne objection to the usual surface coating is that in pouring any but the simplest castings, the coating will be brushed from the prominent parts of the mold and the flowing metal will in a short time cut away portions of the mold and thus destroy its utility. Other objections are that some of the coating materials heretofore used cause pitting of the castings and others will not adhere to the mold at the high tem peratures necessary for producing soft, perfeet castings.

The object of our invention is to produce in permanent molds, castings with smooth,

Application filed January 27, 1921. Serial No. 440,501.

perfectly formed surfaces, whether the molds are hot or relatively cold, and in carrying out our invention we so treat the mold that the protecting material used will not be removed or destroyed or its efficiency injuriously affected either from the heat of the mold or from the contact and flow of the molten metal.

()ur invention is based upon the discovery that the use of certain gasifiable or vapor forming metalliferous substances in the body, or at or On the surface, of the mold, will produce smooth, perfect castings, free from pits or blow-holes and will prevent the adherence of the metal to the mold, although the mold is maintained at a relatively high temperature. Our invention is also based on the discovery that if the gas-forming substance used is readily oxidizable at a temperature below the melting point of the metal being cast a protective coating of oxide will be formed between the mold and the metal. The term gas will be used herein to include both gas and vapor.

WVhile our invention is not limited to the use of zinc as the gas-forming material used, zinc is especially suitable for use in casting ferrous metals in molds containing ferrous metals for the reason that zinc has a vaporizing point below the melting point of iron, and thus will produce a small amount of vapor or gas substantially in film form lee-- tween the mold and the casting, when subj ected to the heat of the molten metal. This will operate to protect the mold and produce smooth castings. Some of the vapor or gas may be partially taken up by the mold or the casting, or both, and if any remains after the castin is discharged it will be precipitated as w ite oxide of zinc on the surface of the mold. The heated zinc metal at its surface will also be oxidized by contact with the air.

Our invention may be so utilized as to make possible the pouring of repeated castings without repeating the treatment or it may be so utilized as to enable the molds to be quickly and easily treated after-each casting or pouring operation. The invention may be utilized in connection with composition molds as well as metallic molds. With our invention the castings may be easily discharged from the mold as soon as they have set sutlicientl y to retain their form or they may be permitted to remain in the mold as long as desired, whether the mold is hot or cold, without injuriously affecting the surface of the matrix or adhereing thereto.

In carrying out our invention it is desirable to provide only a small volume of gas at each casting operation, since an excess of gas may cause pittingand the production of rough, imperfect castings. 1th our process we are able to control, within reasonable limits, the amount or rate of gas formation, either when the gas forming substance is incorporated in the body of the mold, or when it is located on the molding surface. If the gas forming substance is incorporated in the body of the mold, the heat from the molten metal, when it comes in contact with the molding surface, will cause the formation of a limited amount of gas, and both during the casting process and in the interim be tween successive castings the gas forming substance will automatically approach theheated molding surface and thus replenish the supply of such substance where it is needed. Also the oxide of the gas forming material will be produced and form a surface coating on the mold which will tend to reduce the amount of the gas formed. If the oxide is itself gasifiable, it will generally only be so at a higher temperature than that at which the oxide is formed and the amount of gas produced from the oxide will be comparatively small. In this way the supply of the gas forming substance to the surface of the mold is automatically regulated. If, on the other hand, the gas forming substance is located only on the molding surface, the amounts of gas that are successively formed may be controlled either by regulating the amount of the gas forming substance placed on the surface, or by depositing with it or upon it a suitable heat insulating material, such as lamp black or zinc oxide.

In carrying out our invention we preferably use molds having metal in the material surrounding the matrix of the mold, and for the protective substance we preferably use a metal, or a composition of metals, or metal compounds, which may be generally termed metalliferous substances, that will alloy with, or have an affinity for, or an ionic or electric attraction for, the substance of which the body of the mold is wholly or partiall composed. The substance used for pro ucing the gas must be of such a character that it will gasify at a temperature below the melting point of the metal to be cast, inasmuch as we rely upon the heat of the molten metal to produce the gas. Preferably the vaporizing point of the gas forming substance should be above the maximum temperature at which the mold should be mai1ntained inorder to produce soft, perfect castings and below the temperature of the molten metal to be cast. Any metalliferous material may be used that will gasify or vaporize within such a temperature range and produce a gas at the temperature of the molten metal. The selection of the gas forming substance will therefore depend upon the melting point of the metal to be cast. For instance, if brass is to be cast, gas forming substances having relatively low gasifying points should be used, such as cadmium and zinc chloride. In casting iron, materials such as zinc, cadmium, magnesium and barium may be used. If high speed steel is to be cast, it may be found desirable to use zinc, barium or bismuth as the gas forming material.

\Ve preferably use metalliferous materials that Willalloy with or be absorbed by or have an affinity for the material of which the mold is composed, so that the gas forming substance may be incorporated in the mold or will adhere thereto and thus insure a suitable supply of gas at each casting operation. We therefore find it preferable to use zinc as the gas forming material for molds containing iron when used for producing castings of metals having high melting points, since the zinc has an afiinity for and is electro positive to the iron and will automatically distribute itself under the action of the heat of the molten metal so as to keep the molding surfaces of the mold supplied with the proper amount of zinc, and will form zinc oxide over the molding surfaces. Whether the gas forming substance used will alloy with or be absorbed by the mold material, or merely has an aflinity therefor, it may be deposited on the molding surface in sufficient quantity to form the required amount of gas at each casting operation in making repeated castings.

If the mold material and gas-forming substance are such that the former will absorb the latter, as when iron molds are used with zinc as the gas forming material, the mold may be impregnated with the gas forming material by submerging it in the molten metal preferably until the mold at its surface has become saturated therewith.

The mold is then removed from the molten metal and all the surplus free'metal brushed from the surfaces, when it is ready for use in making a large number of castings.

When the gas forming material is applied to the surface of the mold, it may be deposited thereon by directing it in a gaseous condition against the molding surface, where it will congeal in the form of a powder or form a smooth surface coating, depending on thetemperature of the mold. Also the molds may be placed in a vapor of any of the metals mentioned, which will at the same time surface the mold with the gasiliable metal and the oxide of the metal. If the atmospheric oxygen has opportunity to completely burn the heated vapor then only the oxide will be deposited on the mold or the oxide of any of the metals mentioned may be deposited on the mold in any suitable wa The oxide may be partially reduced either by the reducing action of the molten iron and carbon of the iron, by the carbon deposited as a coating, or by a reducing flame or it may remain in the form of an oxide and act as an eflicient neutral heat insulator and protect the metal of the mold.

When the mold is formed of a composi-- tion of one or more materials, such gas forming material or materials should be selected as may be absorbed by one or more of the ingredients of which the mold is composed, if the protective material is to be incorporated within the mold as distinct from being applied to the surface thereof. Composition molds may be formed of a variety of materials. We have, however, found it preferable to form composition molds of mixtures that contain clay as one of the ingredients. To the clay may be added one or more metals which will melt during the calcination of the clay. The protective material selected, if it is to be incorporated within the mold, may therefore be such that it will be absorbed by the clay or it may be such that it will form an alloy with or have an afiinity for one or more of the metals incorporated in the mold. The composition mold may therefore be formed from a mixture of clay, iron, nickel and other materials, if desired. Molds formed of clay and nickel or of clay and iron we have found will take up or absorb a large quantity of zinc and will deliver it to the molding surface in the same regulative way that the iron molds will control the zinc supplvto their molding surfaces.

The protection afforded to the mold itself by the use of our process is of special importance in the use of composition molds, as the protection thus provided prevents the molten metal from attacking and disintegrating the mold materials, thus materially adding to the life of the molds.

The protective material may lee-incorporated in a composition mold by gasifying the protective. material preferably in a closed receptacle so as to exclude air and prevent oxidization of the protective material, and thus causing absorption of the gas-forming material, which upon chilling will be deposited as a solid within the body of the mold. Composition molds may also be coated with suitable gas forming substances in the same manner that the iron molds may be coated, as described above.

Our invention contemplates the deposit of the protective material at or near the molding surface, that is, in a location where it will have an active protective relation to the mold or the molten metal inserted in the mold, and includes broadly at the surface, on the surface, or within the material surrounding the matrix, but in each case located in a position where it will function in its action as between the mold and the metal of the casting while the casting is contained within the mold.

lVhether the gas producing substance is incorporated in any of the above described molds or,..-used as a surface coating, the amount of the gasification produced by the heat of th molten metal may be regulated by depositing with or upon the gas-forming material a heat insulating material, such as lamp black or other similar material, thatwill not chemically react deleteriously on the materials of the mold, on the as forming substance, or on the metal to e cast in the mold. When lamp black is used, it may be deposited on the surface by means of an incomplete combustion flame produced from a hydrogen carbon gas. When the mold is coated as distinct from being impregnated with th gas forming substance, the heat insulating material may be deposited on the mold over the gas formim substance, or it may be deposited with the gas forming substance. Thus lamp black, or graphite, may be used to cover the coating of the gasifiable mate-rial or it may be deposited with the gasifiable material.

By the us of our invention in connection with the casting of ferrous metals, the castings may be made in heated ferrous molds, and ejected, if desired, while the interior of the casting is still in a molten condition, or ferrous castings may be made in permanent ferrous metal molds, either with or without preheating, and the casting left in the mold until it has hardened throughout. In either case the invention provides a perfect separating means between the casting and the mold which enables assured delivery of all parts of the casting from the mold, even though some of the surfaces of the casting may be drawn over or parallel with the surfaces of the mold.

Since gas forming substances such as we propose to use prevent the adherence of molten metal to metal, or of molten metal to calcined clay, ladles, crucibles, troughs, spouts and other devices or parts of furnaces used in manipulating certain metals, such as iron, brass, etc., while in a molten state, may be treated with substances, such as zinc, magnesium, cadmium, etc., or their oxides and free flow and complete deliver of the metal from the devices will be assur We claim 1. The process of preventing adherence of a metal casting to a mold, which consists in treating the mold with a metalliferous substance and forming between the mold and the casting a gas from the metalliferous substance by the heat of the metal cast.

2. The process of preventing adherence of a metal casting to a mold, which consists in treating the molding surfaces of the mold with a metalliferous substance and forming between the mold and the casting a gas from a the metalliferous substance by the heat of the metal cast.

3. The process of preventing adherence of a metal casting to a mold, which consists in surfacing the molding surfaces of the mold with a metalliferous substance and gasifying the metalliferous substance at the molding surfaces by the heat of the metal cast.

4. The process of preventing adherence of a metal casting to a mold, which consists in incorporating in the mold a metalliferous substance and gasifying a portion of the metalliferous substance at the molding surfaces by the heat of the metal cast.

5. In the process of casting metals, treating the molding surfaces with a metalliferous substance having a gasifying point below the melting point of the molten metal cast and forming a gas from the metalliferous substance at the molding surfaces by the heat of the metal cast.

6. In the process of casting metal, surfacing the molding surfaces of the mold with a metalliferous substance having a gasifying point below the temperature of the molten metal and forming a gas from the metalliferous substance atthe molding surfaces by the heat of the metal cast.

7. In the process of casting metals, incorporating in the molds contiguous to their molding surfaces a metalliferous substance having a gasifying point below the temperature of the molten metal and forming a gas from the metalliferous substance at the molding surfaces by the heat of the metal cast.

8. In the process of casting metals, the steps of incorporating a metalliferous substance in the molds and gasifying successively portions of the metalliferous substance by the heat of the molten metal forming the castings.

9. In the process of casting metals, the steps of incorporating a gasifiable material within the surface of the mold and forming a gaseous film over the molding surface by the heat of the metal cast.

10. In the process of casting metals, the

,steps of inconporating gasifiable material matinee within the surface of the mold and forming afilm of gas from the gasifiable material.

located at the molding surface by the heat of the metal cast. I

11. In the process of casting metals, the steps of incorporatinga gasifiable material within the surface of the mold and forming a film of gas from a portion of the gasifiable material at the moldlng surface by the heat of the metal cast and replenishin the gasifiable material at the surface 0 from the gasifiable material incorporated in the mold.

12. In the process of casting metals, the steps of incorporating a, gasifiable material within the surface of the mold, forming a film of gas at the surface of the mold from the portion of the gasifiable material located at the moldin surface by the heat of the metal cast in t e mold, gasifyin other portions of the gasifiable material located continguous to the surface of the mold and so lidif ing the last named portions of the gasthe mold ifiab e material at the surface of the mold immediately on delivery of the casting from the mold.

13. In the process of casting metals, the steps of incorporating a gasifiable material in the mold by absorption, forming a gaseous film between the molding surface and the metal cast in the mold by the heat of the molten metal, and replenishing the molding surface with the gasifiable material by absorption of portions of the gasifiable material contiguous to the molding surface.

14. In the process of casting metals, the steps of incorporating a gasifiable material within the surface of the mold, forming a film of gas over the molding surface by the heat of the molten metal, and automatically replenishing the molding surface with gasifiable material from the gasifiable material contiguous to the molding surface by vaporization produced by the heat of the metal cast.

15. In the process of casting metals, the steps of incorporating a gasifiable material in the mold by absorption, forming a film of gas over the molding surface by the heat of the metal cast and regulatively replenishing the molding surface with the gasifiable material from the gasifiable material incorporated in the mold.

16. In the process of casting metals, the steps of impregnating the mold with a gas forming substance and a heat insulating material and forming a gas from the gas ill) forming substance between the metal of the molding surface with a heat insulating material and gasifying a portion of the gasifiable material located at the molding surface b the heat of the metal cast.

19. n the process of casting metals, the steps of incorporating a gasifiable material within the surface of the mold, coating the.

molding surface with a heat insulating material. gasifying the gasifiable material lo cated at the molding surface and regulating by the heat insulating material the replenishment of the gasifiable material to the molding surface.

20. In the process of casting metals in molds containing a metal, the steps of treating the molding surfaces with a metalliferous material and forming a gas from the metalliferous material by the heat of the metal cast.

21, In the process of casting metals in a mold containing metal, the steps of incorporating a metalliferous material in the mold and forming a gas from the metalliferous material by the heat of the metal cast.

22. In the process of casting metals in a mold containing iron, the steps of treating the mold with a metalliferous substance and forming 'a gas from the metalliferous substance by the heat of the metal cast.

23. In the process of casting metals in iron molds, the steps of treating the molds with a metalliferous substance and forming a gas from the metalliferous substance by the heat of the metal cast.

24. In the process of casting metals in iron molds, the steps of treating the molds with zinc and forming a gas from the zinc by the heat of the molten metal cast.

25. In the process of casting metals in iron molds. the steps of incorporating zinc in the mold and gasifying successively portions of the zinc by the heat of the molten metal cast.

26. In the process of casting metals in iron molds, the steps of treating the molds with a metalliferous substance and a heat insulating material and forming a gas from the metalliferous substance by the heat of the metal cast.

27. In the process of casting metals in iron molds, the steps of incorporating a metalliferous substance in the mold, coating the molding surface with a heat insulating material and gasifying sucessively portions of the metalliferous substance at the molding surface.

28. In the process of casting metals in in the molds and coating the molding surfaces with heat insulating material and gasi- 'fying sucessively portions of the zinc at the molding surfaces by the heat of the metal cast. I

29. In the process of casting metals in iron molds, the steps of incorporating zinc in the molds, coatin the molding surfaces with lamp black and forming films of gas from the zinc. at the molding surfaces by the heat of molten metal of successive castmgs.

30. In the procem of casting metals in molds, the steps of incorporating a metalliferous substance in the mold and coating the molding surface with a carbonaceous ma terial, and forming a gas from the metalliferous material by the heat of the molten metal cast.

31. The process of preventing the adherence of a metal casting to a metal mold, which consists in incorporatingowithin the surface of the mold a material oxidizable at a temperature below the melting point of the metal.

32. The process of preventing the adherence ofa metal casting to a mold, which consists in treating the mold with a material that will form an oxide over the surface of the mold by heat produced by the metal castings,

33. The process of preventing the adherence of a metal casting to a mold, which consists in treating the mold with a material that will form an oxide over the surface of the mold upon the removalof the casting from themold.

34. In the process of casting a metal the steps of incorporating within the surface of the mold a material that will form successively layers of its oxide on the molding surface upon the removal of successive castings.

35. In the process of casting the metals the steps of treating the mold with a material that will form an oxide on the surface of the mold between successive castings, and coating the mold with a heat insulating material between the successive castings.

36. In the process of casting metals the steps of treating the mold with a metal, heating the mold, and forming an oxide of the metal over the surface of the'mold.

37. In the process of casting metals the steps of incorporating a metal in the mold, and forming successively layers of the oxide of the metal over the molding surface by heat produced from the successive metal castings.

38. In the process. of casting metals the steps of treating the mold with a metal, maintaining the mold at a relatively high temperature, and forming a layer of oxlde of the metal over the molding surface.

39. In the process of casting metals the steps of treating the mold with a gasifiable substance, maintaining the mold at a relatively high temperature, and forming a film of gas-from the substance by the heat produced by the molten metal.

40. In the process of casting metals the steps of treating the mold with a metalliferous substance, coating the molding surface with a heat insulating material, and maintaining the mold at a relatively high temperature below the melting point of the metalliferous substance.

41. Ihe process of preventing the adherence of a metal part of a mold\to a casting which consists in treating the mold with a metal and its oxide.

42. In the process of casting metals in molds, forming a -aseous material at the surface of the molds by the heat of the metal, and oxidizing a portion of the gaseous material to form a coating of the oxide of the gaseous material on the molding surface of the mold.

43. In the process of casting metals, forming a gas from a material at the molding surface of the mold by the heat of the metal, forming the oxide of the material by the heat and the oxygen of the air to form a protective coating on the surface of the mold, and again forming a gas from the material in each subsequent casting operation.

44:. In the process of casting metals in molds, treating the mold with a material that will gasify and form an oxide below the temperature of the melting point of the metal cast in the mold and gasifying the material by the heat of the metal of the casting and depositing the oxide upon the removal of the casting.

45. The process of preventing adherence of a metal to a casting which consists in incorporating within the surface of the mold a material that will produce a gas when heated by the molten metal.

46. In the process of casting metals, impregnating the mold with a metalliferous material having a boiling point below the melting point of the metal cast in the mold in proximity to the molding surface.

47. In the process of casting metals in molds, impregnating the mold in the vicinity of the surface of the matrix with zinc.

48. In the process of casting metals, treating the mold with zinc to prevent adherence of the casting to the mold.

49. In the process of casting metals, treating the mold with a material containing zinc to prevent adherence of the casting to the mold.

50. In the process of casting metals, impregnating the mold with a metalliferous material to prevent adherence of the casting to the mold.

5I. In the process of casting metals in neeaoee molds having metallic molding surfaces, impregnating the surface of the mold with a material that will prevent adherence of the metal cast to the metal of the mold.

52. In the process of casting metals in molds containing metal, impregnating the metal of the mold with a material that will render the metal that forms the casting neutral in its effect on the metal in the mold.

53. In the process of casting metals in molds-containing metal, impregnating the contacting surfaces of the mold and the casting wlth a material that will neutralize the injurious effects between the metals of the casting and the mold.

54:. In the rocess of casting metals in molds containlng metal, impre nating the contacting surfaces of the mo d and the casting with a protecting metalliferous material.

55. In the process of casting metals in molds containing metals, impregnating surfaces of the mold and the casting with a protecting material containing zinc.

56. In the process of casting metals in molds containing metals, impregnating the contacting surfaces of the mold and the casting 'with a neutralizing material containing zinc, and ejecting the casting immediately after the casting has been formed.

57. The process of preventing adherence of a metal casting to a mold, which consists in incorporating in the mold a metalliferous substance and gasifying a portion of the metalliferous substance by the heat of the metal cast, and ejecting the casting immediately after the casting hasbeen formed.

58. In the process of casting metals, treating the mold with a metalliferous substance, coating the molding surface with a heat insulating material, and maintaining the mold at a substantially uniform and relatively high temperature below the melting point of the metalliferous substance, and ejecting the casting immediately after the casting has been formed.

59. In the process of casting metals in molds containing metals, impregnating surfaces of the mold and the casting with zinc.

60. In the process of casting metals, treating the molding surfaces of the mold with a metalliferous substance having a boiling point below the melting point of the metal cast and forming a gas from the metalliferous substance by the heat of the metal cast.

61. In the process of casting metal, incorporating in the mold a metalliferous substance having a boiling point below the temperature of the metal and forming a gas from. the metalliferous substance by the heat of the metal cast.

62. In the process of casting metal in molds containing a metal, treating the molding surface of the mold with a metalliferous substance and forming a gas from the metalliferous Substance by the heat of the metal cast.

63. In the process of casting metals, impregnating the mold with a metalliferous material that will prevent the adherence of the metal to the mold during repeated castin operations.

64. n the process of castin metals, impregnating the mold in the vicinity of the molding cavity with a meta-lliferous material that will prevent the adherence of the metal to the mold during repeated casting operations.

65. In the process of casting metals in molds containing metals, impregnating the metal of the mold with a quantity ofneutralizing material sufiicient to prevent adherence of the casting to the mold during repeated casting operations.

66. In the process of casting metals in molds containing iron, treating the molds with a metalliferous substance and forming a gas from the metalliferous'substance by the heat of the metal cast.

67. In the process of casting metals in molds containing iron, treating the molds with zinc and forming a gas from the zinc by the heat of the molten metal'cast.

68. In the process ofcasting metals in molds containing iron. incorporating zinc in the mold and gasifying successively portions of the zinc by the heat oithe molten metal cast. I

69. In the process of casting metals in molds containing iron. treatng the molds with a metalliferous substance and a heat insulating material and'forming a gas from.

72. In the process of casting metals in I molds containing iron. incorporating zinc in the molds, coating the molding surfaces with lamp black and forming films of gas from the zincat the molding surfaces by the heat of molten metal of successive castings.

73. The process of preparing a mold containing metal near the surface of the matrix mold to the metal casting formed in the mold, which consists in depositing a protective material containing zinc near the surface of the matrix of the mold.

7 4. The process of preparing a mold containing a metal near the surface of the matrix of the mold to prevent the adherence of the mold to the metalcasting formed in the mold, which consists in depositing a protective material containing a zinc oxide near the surface of the matrix of the mold.

75.v The process ofpreparing a mold containing a metal near the surface of the matrixof the mold to prevent the adherence of the mold to the metal casting formed in the mold, which consists in depositing va protective material containing metallic zinc and Zinc oxide near the surface of the matrix of the mold.

76. The process of preparing a mold to prevent. the adherance of ferrous metal castings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing zinc near the surface of the matrix of the mold. I

77. The process of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, v

the mold having a ferrous meta-l near the surface of thematrix of the mold, which consists in depositing a protective material containing metallic zinc oxide near the surface of the matrix of the mold.

78. The processof preparing a mold containing a metal near the surface of the matrix of the mold to prevent the adherence ofthe mold 'to the metal cast ng formed in the mold, which consists in depositing a protective material containing metal .electro positive to the metal of the mold near the surface of the matrix of the mold. and

coatingthe surface of the matrix of the mold with a carbonaceous material.

79. The process of preparinga mold con.- taining a metal near the surface of the matrix of the mold to prevent the adherence of the mold'to the metal castin'g'formed in the mold, which consists in depositing a protective materi al containing zinc near the surfa e of the matrix of the mold. and coating the surface of the matrix of the mold with a carbonaceous material;-

80. The process of preparing a mold containing a metalnear the surface of the matrix of the mold to prevent the adherence of the mold to the metal casting formed in the mold. which conssits in depositing a protective material containing zinc oxide near the surface of the matrix of the mold.

and coating the surface ofthe matrix of the mold with a carbonaceous material.

81. The process of preparing a mold containing a metal near the surface of the in the mold, which consists indepositing a protective material containing metallic zinc and zinc oxide near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with a carbonaceous material.

82. The process of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing metal electro positive to the iron of the mold near the surface of the mold, and coating the surface of the matrix of the mold with a carbonaceous material.

83. The process of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, themold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing zine near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with a carbonaceous material.

84%. The procem of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing metallic zinc and zinc oxide near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with a carbonaceous material.

85. The process of preparing a mold containing a metal near the surface of the matrix of the mold to prevent the adherence of the mold to the metal casting formed in the mold, which consists in depositing a protective material containing metal electro positive to the metal of the mold near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with lamp black.

86. The process of preparing a mold containing a metal near the surface of the matrix of the mold to prevent the adherence of the mold to the metal casting formed in l the mold, which consists in depositing a protective material containing zinc near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with lamp black.

87. The process of preparing a mold containing' a metal near the surface of the matrix of the mold to prevent theadherence of the mold to the metal casting formed in the mold, which consists in depositing a protective material containing zinc oxide near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with lamp black.

88. The process of preparing a mold containing a metal near the surface of the matrix of the mold to prevent the adherence of the mold to the metal casting formed in the mold, which consists in depositing a protective material containing metallic zinc and zinc oxide near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with lamp black.

89. The process of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which con sists in depositing a protective material containing metal electro positive to the iron of the mold near the surface of the mold, and coating the surface of the matrix of the mold with lamp lolaclr.

90. The process of preparinga mold to prevent the adherence of ferrous metal cas ings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing zinc near the surface of the matrix of the mold, and coating the surface of the matrix of the mold with lamp black.

91. The process of preparing a mold to prevent the adherence of ferrous metal castings to the mold while formed in the mold, the mold having a ferrous metal near the surface of the matrix of the mold, which consists in depositing a protective material containing metallic zinc and zinc oxide near the surface of the matrix of the mold, and coating" the surface of the matrix of the mold with lamp black.

92. In the process of-casting metals in molds, treating the molds with a heated metalliferous substance.

93. In the process of casting metals in molds, treating the molds with a heated powdered metalliferous substance.

94:. In the process of casting metals in molds, depositing the heated finely divided metalliferous substance on the surface of th mold. I

95. In the process of casting metals in vmolds, treating the molds with a heated metallic oxide.

96. In the process of casting metals in molds, treating the molds with a heated powdered metallic oxide.

97. In the process of easing metals in molds, treating the molds with the heated powdered oxide of a metal having a melting molds, depositing on the surface of the mold point below that of the metal cast in the a finely divided heated oxide of ametal havl0 mold. ing a melting point below that of the metal 98. In the process of casting metals in cast in the mold. 5 molds, treating the molds with the heated In testimony whereof, we have hereunto oxide of a metal having a melting point be- Signed our names to this specification. low that of the metal cast in the mold. HUBERT A. MYERS.

99. In the process of casting metals in ARTEEMES D. STRAW.