US1160430A - Process of melting aluminum or aluminum alloys. - Google Patents

Description

. ncense.

' No Drawing.

' 1 an eraser seminar on I GEENVILLE MEIJLEN-OF MOUNT VERNON, NEW/V YGRK.

PROCESS OF MEL'IING ALUMINUIVI B ALUMINUM. ALL-0Y5.

To all whom it may concern:

Be it known that I, GRENVILLE ME LEN, citizen of the United States, and residehtof Mount Vernon, in the county of VVestchester and State of New York, have invented certain new and useful Improvements in Processes of Melting Aluminum or Aluminum -Alloys, of which the following is a specification.

process of melting aluminum and its alloys and has forits object to protect and preserve the metal from destruction by oxidation and. to produce ingot and other forms of casting which shall be of a sounder nature to a degreethat has been heretofore the present method of melting aluminum or its alloys, and having these qualities to the desired extent. It is also extremely desirable to obtain a process or method of melting aluminum or its alloys which shall preserve the metal from the great loss suffered by oxidation It is generally known that if molten alu minum ,0! any of its alloys is allowed to remain within the furnace, and the temperature gradually raised, the deterioration of the metal'increases with the rise of the tem perature. .Numerous blow-holes occur when the metal is cast. If the metal is melted with care and skill, of course,many

of these imperfections are avoided. But with, the present methods and processes of melting aluminum or its alloys, the results are far from being satisfactory even if the greatest care is taken by the most skilled hands. The imperfections are inevitable so long as the cause remains; and the causes of these difficulties with the present methods of melting aluminum or its alloys are ever present... I

In the melting of scrap aluminum (thisaluininum is in the majority of cases seldom even. commercially pure, it being Application filed February 10, 1911.

This invention relates to a new and useful a cent. of the whole.

Specification of Letters Patent. lPantignftefl NOV. 1%, H9115,

Serial No. 607,864.

generally an aluminum alloy with copper, sometimes zinc, either or both, and occasionally, though rarely containing other elements), which consist of clippings and stampings of the sheet metal (generally purer aluminum than that "which composes the castings), and the turnings, grindings, and filings which are parts of the I alloys which are adapted to the casting requirements, a great loss is suffered through oxidation. This loss, is generally less in the metals whose compositions more nearly approach pure aluminum. The percentage of loss suffered by these at present varies between ten and forty. It is in the case of the turnings, clippings, and filings that the greatest loss is suffered; theloss ranging between twenty-five and forty per In practice this great loss is seldom less than thirty per cent. Thisloss is practically a total destruction and an absolute waste of valuable metal.

In the instance of the imperfections arising from the blow-holes and the like, I

have found that this is due to the presence of occluded gases, and to the partial dissolution of the oxide, and other foreign and injurious matter.

In the case of the great loss by oxidation,- I'have found that this is due to the presence of oxygen, which e'xists free as a constituent of theair, and in the water vapor which is present in the atmosphere. It is generally known that aluminum decomposes water vapor, forming the oxid of aluminum and liberating the two atoms of hydrogen.

My novel process overcomes these diiiic'ulties, and produces the metal withv the tendency to blow-holes and gas bubbles 'practically obviated. It also preserves the metal to a minimum loss by oxidation; the. percentage of loss being reduced to between one-half and five;

lVith these and other objects in view, I

have made numerous experiments in the melting of aluminum and its alloys, and both of these are in the form of scrap.

It is readily obvious that matter existing in the forms of scrap-aluminum, and the scrap of aluminum alloys exposes a surface area which bears a great numerical proportion to the entire volume of the mass. Therefore a large portion of the metal exists in intimate contact with the oxygen present in the. atmosphere. This same surface is exposed to the number of gases which constitute the atmosphere Within the furnace.

This atmosphere generally contains carbon dioxid, oxygen,

sulfur dioxid, water-vapor, free free nitrogen, and some'free hydro- \gen. All metals will occlude gas under certain conditions, though each may show some partiality as to the nature of the gas.

In carrying out my novel process I prefer to use either of the following methods: The aluminum or'the aluminum alloy to be melted is placed in a melting chamber tight chamber.

which is inclosed in an air The air is" then removed from the said air tight chamber, thus creating a partial vacuum therein. Any inert gas is now admitted into the said air-tight chamber. The metal melted in this atmosphere. The object of this-inert gas is to pro.-

vide an atmosphere which shall serve as a means of conducting the heat to all parts of the metal not in direct contact with the heat-.

. ed walls of the said crucible or melting chamber, and to provide an atmosphere which shall be free from active oxygen or other corrosive gases which act upon aluminum' or aluminum alloys. After the metal is melted in this inert atmosphere and while the metal is yet molten, theinert gas is removed, thus again creating apartial vacuum within the said air-tight chamber.

The molten metal is allowed to remain therein until much of the occluded gas is expelled from the pores of the aluminum or the aluminum alloy. The metal is then ready for pouring which should be done as quickly as possible to prevent the further occlusion of gas.

In the melting of aluminum or aluminum alloys to prevent the occlusion of gases by the metal a-nd'to prevent its great loss by oxidation, if preferred the metal may be placed in a crucible or other suitable melting chamber, the whole inclosed within an airtight chamber and the air removed: from Copies of this patent may bechbained for crucible or in any suitable.

chemically inert'toward aluminum alloy, then creating a partial vacuum within the melting chamber while the aluminum or the aluminum alloy is yet molten. I

2. The process of melting aluminum or an aluminum alloy which consists in creating a partial vacuum within'the melting chamber, then. admitting a gas which is substantially the aluminum or the aluminum alloy into the melting chamber, and then melting the aluminum or the aluminum alloy in this atmosphere which is-substantially chemically inert toward the aluminum or the aluminum alloy. I

- 3. The process of melting aluminum-or an aluminum alloy which consists in creating a partial vacuum within the melting chamher, then admitting a gas-which is substantially chemically inert toward the aluminum or the aluminum alloy into the melting chamber, then melting the aluminum or the aluminum alloy in this atmosphere which is substantially chemically inert toward the aluminum or the aluminum alloy, andthen creating a partial vacuum within the said melting chamber While the aluminum aluminum alloy is yet molten.

4. The process of melting aluminum or an aluminumalloy which consists in creating a partial vacuum within the melting chamber, then admitting into the melting-chamber a reagent which has the property of combining with the oxygen present within the melting chamber thereby producing an atmosphere Within the melting chamber which is substantially chemically inert toward the aluminum or the aluminum alloy and then melting the aluminum or the aluminum alloy il' this atmosphere which is substantially chemically inert toward the aluminum or the aluminum alloy.

Signed at New York New York and State of New York this 9th day of February A. D. 1911.

Witnesses:

FRED. F. KUHLMANN, S. R. MILLER.

five cents each, by addressing the Commissioner" of Patents, Washingtoml). G.

city in the county 0i GRENVILLE MELLEN.

or the