US2139516A

US2139516A - Alloys for addition to iron and steel

Info

Publication number: US2139516A
Application number: US204191A
Authority: US
Inventors: George L Norris
Original assignee: Vanadium Corp of America
Current assignee: Vanadium Corp of America
Priority date: 1938-04-25
Filing date: 1938-04-25
Publication date: 1938-12-06
Anticipated expiration: 1955-12-06

Description

Patented 6, 1938 hurrah sT 'ras rarest orries No mrawinn. Appilicaflnn April 25, 1000,, Burial No. itlliinmll mins.

This invention relates to an alloy containing silicon, titanium, zirconium, aluminum and iron, and especially to an alloy suitable for additions to molten iron and steel for the purpose of obtain- 'ing a more sound, dense and clean metal when such steel or iron solidifies.

The present application is a continuation-in-= part of my copending application, Ser. No. 128,- 231, filed February 27, 1937.

, The use of term-silicon, term-titanium, ierro zirconium, aluminum, farm-aluminum, iron-sill con-zirconium, arid iron-silicon-titanium tor the purpose of scavenging molten steel and iron is very well-known and these alloys are more or less generally employed in iron and steel manufacturing practice. Their use, however, is accompanied by very marked deficiencies so that, while they ireethe molten metal of impurities, such as iron oxide and iron nitride by chemically reacting 2G with these compounds, the products: iron-silicate, alumina, titanium cyanonitrides, and zirconium cyanonitrides, remain entrapped in the metal, thereby imparting to it several objectionable qualities. The amount of non-metallics remaining entrapped in the metal is not always the same- Therefore, iron and steel alloys are obtained which have varying physical qualities, such as ductility, although of the same chemical composition.

80 I have discovered that the combination 0! all four elements-silicon, titanium, zirconium and aluminum-with iron, in proper proportions, pro, duces an alloy which when added to molten iron and steel reacts with gaseous, and other impurities in the molten metals to form reaction products which more readily coagulate and separate from the molten iron or steel. My alloy is readily soluble in molten iron or steel and is more eflective and economical than alloys containing one or two of the elements silicon, titanium, zirconium, aluminum alone or in combination with iron.

My alloy not only acts as a' scavenger in molten iron and steel, 1. e., removes the-various impurities in the molten metal, but also serves to control the grain size 01 the treated product.

While my alloy is composed of silicon, titanium, zirconium, alumin and iron and is substantially free from carbon, there may be present small percentages of other elements incidental to the method at production or in the raw materials (631i. lid- 50) used. For example, the chemical composition of one melt of this alloy which may be considered typical in respect to the presence of the other metals, is:

Per cent 5 fiilicon 31.20 Titanium 11.70 Zirconium 9.75 Aluminum 0.50 Manganese 0.07 10 Carbon 0.06 liron Balance This alloy is substantially free from carbon, but the carbon content may vary up to a maximum oi about 2.0% or even up to 10.0%, dependmg upon the method of manufacture and intended use. In many cases, I prefer to have the carbon below 0.15%.

The improved composition of my present invention consists oi. an alloy with a minimum amount of carbon so as to be substantially free from carbon and contains about 10% to 50% silicon, preferably about 10% to 45% silicon, about 5% to 15% or titanium, about 5% to 15% or 25% zirconium, andabout 5% to 15% or 25% alumi- 25 num. In no case, however, does the sum 01 the silicon, titanium, zirconium and aluminum exceed 90%. The percentage of silicon is at least equal to or greater than the percentage of either the titanium, the zirconium or the aluminum. The remainder of the alloy is principally iron, although usual impurities or small amounts of other alloying elements may be present.

While I have described my alloy in its preferred composition, it is to be understood that the in- 3 vention is not so limited, but may be otherwise embodied within the scope of the following claims.

I claim:

1. An alloy for addition to iron and steel, containing about 10% to silicon, about 5% to 25% titanium, about 5% to 25% zirconium, about 5% to 25% aluminum, the sum of the silicon, titanium, zirconium and aluminum not exceeding and not over about 10.0% carbon, the remainder being principally iron.

2. An alloy for addition to iron and steel, con--' taining about 10% to 50% silicon, about 5% to 25% titanium, about 5% to 25%. zirconium, about 5% to 25% aluminum, the sum of the silicon,

' titanium, zirconium and aluminum not exceeding 90%, and not over about 2.0% carbon, the remainder being principally iron.

3. An alloy for addition to iron and steel, containing about 10% to 50% silicon. about 5% to 25% titanium, about 5% to 25% zirconium, about 5% to 25% aluminum, the sum of the silicon. titanium, zirconium and aluminum not exceeding 10 90%, the percentage of silicon being not less than