US886858A - Process of producing low-carbon ferro-alloys. - Google Patents

Description

electric furnace, the relative afiinities of the molten alloy of iron, a highly-positive metal UNITED STATES PATENT OFFICE.

EDGAR F. PRICE, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO ELEOTRO METALLURGICAL COMPANY, OF OHIOAGO ILLINOIS,

CORPORATION OF WEST VIRGINIA.

PROCESS OF PRODUCING LOW-CARBON FERRO-ALLOYS.

Specification of Letters Patent.

Patented May. 5, 11908.

A Applicationfiled September 24, 1907. Serial N 0. 394,254.

To all whom it may concern:

Be it known that I, EDGAR F. PRICE, a citizen of the United States, residing at Niagara Falls, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Processes of/Producing Low-Carbon Ferro-Alloys, of which the following is a specification.

The value of the ferro-alloys commonly employed as a means of introducing chromium, vanadium and other metals into special steels, is largely de endent on a low carbon content, and met ods of reduction involving the use ofexpensive metallic reducing agents, or giving low yields, are employed to produce these alloys.

The present process of producing low-carbon ferro-alloys comprises two stages. In the first stage, a hi h-carbon ferro-alloy, for example one of fiiromium, molybdenum, tungsten, titanium, vanadium or nickel, is cheaply produced by smelting a mixture of an ore of the alloying metal, an excess of carbon and a source of iron. The reduction may be effected in an ordinary electric furnace having a carbon lining and depending carbon electrodes.

In the second stage, the carbon is removed or reduced to a small ercentage by electrically heating the mol fenalloyto a temperature such that the affinity of oxygen for the contained carbon is greater than its aflinity for the chromium or other alloyed metal,- and then subjecting it for a limited period to the'action of air or other oxidizing gas. In the ordinary Bessemer process of producin steel, the molten pig-iron containing a sma 1 amount of silicon or other highlypositivemetal and carbon is subjected to the action of air at temperatures such'that the affinity of oxygen for the silicon or other alloyedpositive-metal is greater thanits affinity for carbon, so that the removal of the alloyed metal substantially precedes the removal of carbon. But when the temperature of a and carbon, is'raised to a definite, oint, dependent on the particularalloyed metal, a temperature above that employed in the Bessemer steel industry or usually roduced by combustion but readily-obtaina le in an alloyed metal and carbon toward oxygen change, the heat of combination of the carbon and oxygen becomesgreater than the heat of combination of the alloyed metal and oxy gen, and the carbon may then be largely or substantially eliminated by oxidation before any considerable percentage of the-alloyed metal is removed.

In carrying out the second stage of the process, the high-carbon ferro-alloy is heated to the requisite temperature by su porting the body of the molten alloy in the orm of a ring or closed loop, and making this body the secondary of astatic transformer, the rimary of which is fed with an alternating,

ulsatin or intermittent electric current.

ither t e entire mass of alloy to be decarburiz'ed may be comprised in this ring, or the ring may comprise an are or loop of molten alloy the ends of which join the main mass. When the alloy is thus, heated to the re uisite high temperature, either in the re uction furnace orin a separate vessel, it is forced through the alloy or caused to act upon its'surfaoe, as in the present art of bessemerizingpig-iron.

I claim:

1. The process of producing low-carbon ferro-alloys, which consists in first producing a'ferro-alloy high in carbon, heatingxthe roduct to a temperature such that t e a of oxygen for the contained carbon is greater than its affinity for the alloyed metal, by constituting a body of the molten alloy the secondary of a transformer and su plying electric current to'the primary of sai transformer, and subjecting the heated alloy to the action of an oxidizing gas.

2. The process of producing low-carbon ferro-alloys,= which consists in electrically smelting a compound of the alloying metal, an excess of carbon'and a source of iron, heating the product to a temperature such that the affinity of oxygen for the contained carbon is greater thanits aflinity for the alloyed metal, by constitutin a body of the molten alloy the secondary of a transformer and supplying electric current to the primary of said transformer, and subjecting the heated alloy to the action of an oxidizing gas. y

3. The process of producing low-carbon ferrochromium, which consists in first pro:

by constituting a body of the molten alloy the secondary of a transformer and supplying electric current to the primary of said transformer, and subjecting the heated alloy to the action of an oxidizing gas.

4. The process of producing low-carbon ferrochromium, which consists in electrically smelting a compound of chromium, an excess of carbon and a source of iron, heating the product to a temperature such that the aflinity of oxygen for the contained carbon is greater than its afiinity for chromium, by

constituting a body of the molten alloy the secondary of a transformer and su plying electric current to the primary of sai transformer, and subjecting the heated alloy to the action ofan oxidizin gas.

In testimony whereof, %affix my signature in presence of two witnesses.

G. E. Cox, I. R. EDMANDS.