US1767764A - Mold wash - Google Patents

Description

Patented June 24, 1930 UNITED STATES PATENT OFFICE AUGUSTUS E. KAYES AND FRITZ MOEHLING, F HUNTINGTON, WEST VIRGINIA, AS-

SIGNORS TO THE INTERNATIONAL NICKEL COMPANY, INC., OF NEW YORK, N. Y.,

A CORPORATION OF DELAWARE MOLD No Drawing.

This invention relates generally to the casting of nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% of the alloy,

and more particularly to a mold wash and the method of making the same whereby the process of casting nickel or nickel alloys may be efficiently carried out.

Whenever molten metal is poured into molds, and particularly when molten metals of high melting point, such, for example, as nickel or nickel alloys, are poured into ingot molds from a considerable height, splashing will occur regardless of the amount of care exercised in the pouring. This splashing results in the formation of pellets or waves of metal as the molten material comes into contact with the inside surfaces of the mold.

Ingot molds ordinarily are made out of cast iron which readily transmit heat. If a high melting point metal such as nickel or Monel metal is being poured, the pellets or Waves of metal splashing onto the surface of the mold become cool. As the pouring continues these pellets may become loosened from the surfaces of the mold and either float to the top of the ingot or become lodged at some other place along the surface of the mold. The resultant ingot therefore, has a rough surface which must be milled off. It usually is necessary to mill off from to inch of the metal in order to remove this rough surface.

In accordance with our invention, we provide a method of casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which a mold wash is utilized. The utilization of our mold wash results in a casting having a much improved surface. Our mold Wash is of a character such that it can be easily applied to the interior of the mold, either b a brush or a spray gun. The application 0 the mold wash to the surface of the mold eliminates or decreases the amount of splashing. In case a slight amount of splashing does occur, it decreases the bad effects of such splashing.

\Ve have found that very good results are obtained by using a mold wash comprising 50 a deoxidizer, preferably a metallic deoxi- Application filed April 18,

WASH

1929. Serial No. 356,299.

dizer such as silicon, magnesium, zinc or aluminum, with an organic vehicle such as shellac or tar, or with an inorganic vehicle, such as boraX.

If desired, a mixture of an organic and an inorganic vehicle may be employed with the deoxidizer. In our preferred mold wash, we employ powdered silicon in a shellac vehicle. The wash, because of its relatively soft nature as compared with the metal of a mold, decreases the amount of splashing during pouring. The powdered silicon acts to deoxidize the metal as the latter comes in contact with the mold, as well as to give a smoothing mechanical effect. The shellac not only acts as a vehicle to carry the powdered silicon, but it is also a sufficiently good binder so that the use of a bonding material such, for example, as water glass or molasses, is not required.

In addition to decreasing the amount of splashing and also acting as a deoxidizer, the wash acts as an insulating medium for the mold, thereby causing any pellets Which may splash onto the surfaces of the mold to retain their heat longer than they would if they contacted with an iron mold. This de creases the tendency toward segregation on the surfaces of the mold because the pellets tend to melt when the main charge of metal 30 is poured into the mold. The surface of an ingot produced in a mold which has been coated with this wash is decidedly superior to that of an ingot made in the same mold without the coating. The practice of this invention has resulted in a 50% reduction of milling scrap losses.

In preparing the preferred mold wash of silicon and shellac, from two to five parts of commercial powdered silicon are mixed produced combines the deoxidizing properties of silicon with the reducing and bind ing properties of shellac. Both the silicon and the shellac produce a repellant action to the splashing of the metal against the mold surfaces.

The invention is particularly applicable to the casting of high melting point metals in ingot molds, since in such a process there is a great tendency for splashing of the metal and segregation of the pellets of material which contact with the mold surfaces. However, the invention is also applicable to the casting of lower melting point metals, either in ingot molds or sand molds. Our mold wash may also be used in connection with the production of chilled castings.

e have described the present preferred method of practicing our invention and have set forth the proportions which we prefer to use in preparing the mold wash. The inventions may be otherwise practiced and variations in the proportions of the materials making up the mold wash may be employed within the scope of the following claims.

WVe claim:

1. A coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% of the alloy, comprising a mixture of powdered silicon and a vehicle therefor.

2. A coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% ofthe alloy, comprising a mixture of powdered silicon and an organic vehicle therefor.

3. A coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% of the alloy, comprising a mixture of powdered silicon and a shellac vehicle.

4. A coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% of the alloy, comprising a mixture of from two to five parts powdered silicon and from eight to sixteen parts shellac.

5. The process of making a coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or man-- ganese, in which the nickel constitutes at least 30% of the alloy, comprising mixing powdered silicon, shellac and a solvent for the shellac.

6. The process of making a coating or wash for molds for casting nickel or nickel alloys with copper, chromium, iron, or manganese, in which the nickel constitutes at least 30% of the alloy, comprising mixing powdered silicon, shellac and alcohol, and

set our hands.

AUGUSTUS E. KAYES. FRITZ MOEHLIN G.