US1346343A - Alloy of iron, chromium, and titanium and process for the production - Google Patents

Description

UNTTED STATES PATENT OFFICE.

HUGH O. SIGARD, 0F BUFFALO, NEW YORK, ASSIGNOR TO UNITED STATES TERRO- ALLOYS CORPORATION, OF YORK, N. Y., A CORPOBATOIN OF NEW YORK.

ALLOY OF IRON, CHROMIUM, AND TITANIUM AND PROCESS FOR THE PRODUCTION THEREOF.

No Drawing.

To all whom, it may concern Be it known that I, HUGH C. SIoARD, a citizen. of the United States of America, and a resident of the city of Buffalo, county of Erie, and State of New York, have invented a new and useful Alloy of Iron, Chromium, and Titanium and Processes for the Production Thereof, of which the following is a full, clear, and exact description.

This invention relates generally to the manufacture of chrome steel, that is, a steel containing various amounts of chromium.

In the manufacture of chrome steel, it is well known that much difficulty is experienced in obtaining the desired quality of product owing to the fact that some of the added chromium is oxidized by the oxids contained in the steel.

I have found that if an alloy of iron, chromium and titanium, is used for making the chrome steel, the titanium, being more readily oxidized than the chromium, can

be used to eliminate the oxids in the steel and thus protect the chromium from oxidation when it is added to the steel. This invention is designed to overcome the difliculties of oxidation above referred to.

In making this alloy, I use as a source of chromium, the chromium ore known as chromite which contains from 4L0% to 57% chromic oxid (C130 from 10% to 20% of iron oxid (FeO), and certain impurities such as alumina, magnesia, etc. As a source of titanium, I use a titaniferous ore, and preferably rutile which contains 95% or more titanic oxid (TiO The materials above named are mixed with scrap iron which supplies the iron content of the alloy and there is introduced into the mixture an amount of carbon sufiicient not only to reduce the chromic oxid and the titanic oxid, but an excess thereof so as to form, in the finished alloy, carbide of chromium, titanium and iron. When necessary, such fluxes as sand, lime and the like may be added to the mixture in order to slag off the impurities contained therein.

The mixture is smelted in an open, electric furnace, for example, of the Siemens type. Upon reduction, this mixture gives a bath of -ferro-chromium, titanium and a slag. After reduction, they may be tapped separately or together as desired by the same taphole.

Specification of Letters Patent.

Patented July 13, 1920.

Application filed August 18, 1919. Serial No. 318,331.

I have found this alloy to be a complex carbid of chromium, titanium and iron, the amount of carbon varying from 3% to 9%. When added to molten steel the titanium content, on account of its great affinity for oxygen, will oxidize first, thus avoiding any great loss of chromium.

One of the best alloys that T have found is one which contains the elements named in the following proportions:

Chromium from to 75% Titanium about 5% Carbon from 6% to 10% Iron from 34% to 10% It should be noted, however, that I have been using alloys having titanium contents both lower and higher than above set forth. I have been able to secure very good results from a titanium content of from 1% to 16%. It is to be understood, therefore, that the above percentages may be substantially varied and still the desirable results secured from the practice of my invention, that is, the results of protecting the chromium from being oxidized. It is, of course, understood that there are usually unavoidably present in the finished products, some impurities such as silicon and aluminum.

Having thus described my invention, what I claim is:

1. A method for the production of alloys of iron, chromium and titanium comprising the mixture of chromium ore, rutile ore, scrap iron and carbon in sufficlent quantity not only to reduce the chromium and tltanium oxids present in the ores 'but enough to combine with the chromium, titanium and iron to form a complex carbid in the finished alloy-, and then smelting this mixture in an electric furnace.

2. A method for the production of alloys of iron, chromium and titanium comprising the mixture of a suflicient quantity of chromium ore to yield from 55% to 7.5% chromium in the finished product, a sufficient quantity of rutile ore to yield from 1% to 16% titanium in the finished product, carbon in such an excess quantity over that required for the reduction of the oxids that the finished product will contain from 6% to 10% carbon and a suflicient quantity of'scrap iron so that the balance of percentage in the finished product will have an iron content and then smelting thismixture in an electric furnace.

3. A method for the production of alloys of iron, chromium and titanium comprising the mixture of chromium ore, rutile ore, scrap iron and carbon in sufficient quantity not only to reduce the chromium and titanium oxids present in the ores but enough to combine with the chromium, titanium and iron to form a complex carbid in the finished alloy, a suflicient quantity of a suitable flux to make a-fusible slag, and then smelting this mixture in an electric furnace.

4. As a new article of manufacture an alloy of chromium, titanium and iron composed of from 55% to 75% chromium, from 1% to 16% titanium, from 6% to 10% carbon and the balance iron.

In testimony whereof I have hereunto signed my name. 1

HUGH C. SIGARD.