US2791501A

US2791501A - Vanadium-carbon-iron alloy

Info

Publication number: US2791501A
Application number: US405237A
Authority: US
Inventors: Joseph H Brennan
Original assignee: Union Carbide and Carbon Corp
Current assignee: Union Carbide Corp
Priority date: 1954-01-20
Filing date: 1954-01-20
Publication date: 1957-05-07
Anticipated expiration: 1974-05-07

Description

United States Patent VANADIUM-CARBON-IRON ALLOY Joseph H. Brennan, Niagara Falls, N. Y., asslgnor to Union Carbide and Carbon- Corporation, a corporation of New York No Drawing. Application January 20, 1954, Serial No. 405,237

1 Claim. (Cl. 75-129) This invention relates to a vanadium-carbon-iron alloy having a high vanadium content and being suitable for use as an alloying agent to add vanadium to a bath of molten metal. The principal object of the invention is the provision of such an alloy which is readily soluble in molten steel and which in relatively small amount, is capable of introducing a desired proportion of vanadium to steel in the ladle.

In the production of vanadium-containing steels vanadium is customarily added in the form of ferrovanadium to a bath of molten steel, in the ladle in open hearth practice and in the furnace in electric furnace practice. Commercial ferrovanadium usually contains 35% to 55% vanadium; 1.5% to 12% silicon; 0.2% to 3.5% carbon; remainder iron although some grades have as much as 60% vanadium and some grades as low as 1.25% silicon. It is usually produced by silicon-, aluminumor carbon-reduction methods.

Vanadium is readily oxidized, and this is one of the reasons it is preferred to add it .in the ladle rather than in the furnace. The relatively low vanadium content of commercial ferrovanadium makes it necessary to add relatively large quantities of the alloy which tend to cool the bath and thereby impede solution. Further, the high silicon content of commercial ferrovanadium, which as stated above is conventionally in the range 1.5% to 12%, is disadvantageous where it is undesired to raise the silicon content of the metal to which vanadium is to be added, as for example in the production of the vanadium-bearing rimming steel described in U. S. Patent No. 2,356,450.

The alloy of this invention is free of these disadvantages, containing substantially more vanadium and having a lower silicon content. It contains 60% to 90% vanadium; 3.5% to 10% carbon; less than 1%, and preferably not more than 0.5 silicon; the remainder iron and incidental impurities, the iron content being at least 5%. A more specific range of composition is 65% to 80% vanadium; 5% to carbon; remainder iron and incidental impurities. Particular alloys according to the invention are tabulated below as specific examples.

Percent composition-Remainder Fe V C Si 2,790,501 Patented May 7, 1957 The alloy of the invention is economically produced by the direct carbon reduction of commercial vanadium oxide, which is usually a sodium polyvanadate, or sodium hexametavanadate. A mixture of vanadium oxide and carbon is fed continuously to a carbon lined electric furnace in which the alloy is formed as a hearth. When the hearth or regulus is cool it is removed from the shell and crushed.

By way of example, in one production run 100 parts by weight of commercial fused vanadium oxide containing about 88% vanadium oxide calculated as V205 was smelted with 43 parts by weight of charcoal and 5 parts by weight of steel scrap in electric furnace operating at 160 volts and a power input of 200 to 250 kilowatts. In this operation an alloy containing 77.47% vanadium;- 7.3% carbon; 0.31% silicon; remainder iron and incidental impurities was produced.

By reason of the high vanadium content of the alloy of the invention, it is more suitable for ladle and mold additions than present commercial ferrovanadium since lesser quantities are necessary to add the same quantity of vanadium to the metal being treated. This reduces the chilling effect and enhances solution of the alloy in the bath. Further, being low in silicon, the use of the alloy of the invention does not undesirably increase the silicon content of the metal to which it is added. Additionally, the alloy of the invention seems to be less susceptible to oxidation than commercial ferrovanadium when it is added to rimming steel, and vanadium recoveries of the order of 80% or more have been obtained in such use.

The alloy is also useful in the manufacture of high carbon steels, for instance high-speed tool steels, containing vanadium.

This application is a continuation-in-part of application Serial No. 283,137, filed April 18, 1952, now aban- .doned.

What is claimed is:

In the manufacture of a steel having the characteristics due to rimming and containing vanadium between 0.01% and 0.15%, the improved process for imparting such vanadium to such steel which comprises providing a quantity of molten rimming steel and adding thereto an alloy containing vanadium; 5%-10% carbon, less than 1% silicon, the remainder iron and incidental impurities whereby to add the desired quantity of vanadium to such steel without introducing thereto sulficient silicon to affect its rimming characteristics.

References Cited in the file of this patent UNITED STATES PATENTS Moissan Oct. 5, 1897 Saklatwalla June 4, 1929 OTHER REFERENCES