US1150201A - Process of treating cast-iron. - Google Patents

Description

J. E. JOHNSON, JR.

PROCESS OF TREATING CAST IRON.

APPLICATION FILED 0:0. 8. 1913.

1,150,201. atentd Aug. 17, 1915.

Attest: nvento 2210 11 by .f Lm

M W A S.

UNITED STATES PATENT OFFICE.

JOSEPH E. JOHNSON, JR., NEW YORK, N. Y.

PROCESS OF TREATING- CAST-IRON.

Specification of Letters Patent.

Patented Aug. 17, 19115.

Application filed December 8, 1913. Serial No. 805,251.

To all whom it may concern:

Be it known that I, Josnrn: E. JOHNSON, J12, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes of Treating Cast-Iron, of which the in, the oxygen tending to cause the carbon to take the combined rather than the graphitic condition, and causing the graphite formed when the metal cools, to take the form of nodules rather than that of flakes.

For certain purposes it is very desirable that the iron be of this structure, but for other purposes for which cast iron is used, such structure of the iron is objectionable and therefore it is desirable to remove the oxygen so that the iron will not only be free from chilling properties but the graphite will take the form of flakes, these two conditions conducing to softness of the iron.

In the'removal. of the oxygen, which is the aim of my invention, I take advantage of the chemical reactions which will occur between oxygen and other constituent elements of the iron, such as silicon and carbon,

under temperature conditions considerably higher than the temperature at which the iron comes from the furnace, and while subjecting a bath of the molten iron to such temperature conditions, I, in accordance with my invention, maintain such a condition above the surface of the bath, that oxygen will be prevented from entering the bath at this point. As a result of this proceeding, the oxygen will be effectually removed, leaving the iron free from chilling qualities and the graphite in flaky form.

In the accompanying drawings, I have shown an electric furnace of the induction .type which I find preferable for carrying my process into practice.

In the practice of the process I heat a bath A of cast iron 1 an electric furnace B constructed with a chamber or space b above the surface of the bath the purpose of which will presently appear. The degree of heat given the bath is such as to promote reactions between the oxygen and other constituent elements of the iron particularly silicon and carbon, the oxygen combining with the silicon and forming silica which will float on the surface of the bath,

and combining also with the carbon of the bath, thereby forming CO gas which will leave the bath in the form of bubbles. The temperature which I find necessary to promote these reactions, is considerably above that of the iron when it is tapped from the coke furnace, and should be as high as 3000 F. or thereabout. During the heating of the bath and while the above mentioned reactions are taking place, I maintain above the surface of the bath, such a condition that oxygen will be prevented from entering the metal from the outside. Preferably this condition is brought about by giving the atmosphere above the bath a reducing quality, by injecting into the chamber 6, any desired quantity of CO gas ,even as high as 100% of the same. O'r hydrogen gas may be employed for this purpose, or any of the many hydrocarbon gases. gas may be so introduced into the chamber b, as to force out the atmospheric air and products of the reactions taking place in the bath, the efiect of which will be to main tain above the surface of the bath, a condition of atmosphere which will prevent the entrance of oxygen into the bath.

By the employment of an electric furnace for heating the bath, the degree of heat ob- Such tainable is under absolute control, and does ing in the removal of the oxygen to the final point or externally. W'hile suchconditions may be brought about as above stated by inof such baths, the size of the electrodesw ould be unduly large, and therefore such furnace would not, be as suitable as that shown.- It

will be understood therefore that my improved process is not limited in its practice to the particular type of furnace shown, but

- may be carried into effect by any means by which the results described above are brought about.

Having thus described my invention what I claim is:

1. The process of removing oxygen from cast iron, which consists in heating a bath of said iron to a temperature high enough to promote reaction between the oxygen and other constituents of the bath, while maintaining a condition above the bath which will prevent the entrance of oxygen therein.

2. The process of removing'oxygen from cast iron, which consists in heating a bath of said iron in the presence of a reducing atmosphere to a temperature high enough to promote reaction between the oxygen and other constituents of the bath.

v 3. The process of removing oxygen from cast iron, which consists in heating a bath of said iron to a temperature above that at which the metal comes from the furnace, uch temperature being high enoughto promote reaction between the oxygen and other constituents of the bath, while maintaining Copies of this patent may be obtained for a condition above the bath which will pre vent the entrance of oxygen therein.

4. The method of removing oxygen from cast iron, which consists in heating a bath of said iron in an electric furnace to a term perature which will promote reaction between the oxygen and other constituents of the bath, said heating being carried on under conditions which will prevent the entrance of oxygen into the bath.

5. The method of removing oxygen from cast iron, which consists in heating a bath of said iron in an electric furnace to a temperature well above that at which the iron .comes from the coke furnace, such temperature being high enough to promote reaction between the oxygen and other constituents of the bath, and maintaining over said bath an atmosphere of a reducing nature to prevent the entrance of oxygen into the bath.

6. The method of removing oxygen from cast iron, which consists in heating a bath of said iron in an electric furnace to a temperature well above that at which the iron comes from the coke furnace such temperature being high enoughcto promote reaction between the oxygen and other constituents of the bath, whilemaintaining such a condition above the bath that oxygen will be prevented from entering therein.

7. The method of removing oxygen from cast iron, which'consists' in heating a bath of said iron to a temperature sufficient to promote reactions between the oxygen, silicon and carbon of the bath, while maintaining such a condition above the bath that the entrance of. oxygen therein will be prevented.

In testimony whereof I have affixed my signature in presence .of two witnesses.

v JOSEPH E. JOHNSON, JR J Witnesses:

. WM. J. DOLAN, WV. R. K NNEDY.

fivecents each, by addressing the "Commissioner of Patent. Washington, D. G.

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