US1483298A - Alloy comprising iron, nickel, chromium, molybdenum - Google Patents

Description

Patented Feb. 12, 1924.

UNITED STATES PATENT OFFICE.

PIERRE GIRIN, OF PARIS, FRANCE, ASSIGNOR TO SOCIETEANONYME DE COMMENTRY, FOURCHAMBAULT & DECAZEVILLE, OF PARIS, FRANCE.

ALLOY COMPRISING IRON, NICKEL, CHROMIUM, MOLYBDENUM.

No Drawing. Original application filed December 9, 1918, Serial No. 265,985. Divided and this application filed February 8,

To all whom it may concern:

Be it known that I, PIERRE GIRIN, a citi-' zen of France, and a resident of Paris,

France, have invented new and useful is ralsed from 400 to 500 C. and the hard 'ness conferred by a suitable tempering disappears at the same time as the reheating annuls the action of the treatment.

The high speed steels certainly preserve their hardness at a temperature higher than the other steels, and after they have been tempered possess a high resistance, even up to a red heat, but besides the drawbacks 2 which result from their fragility and difficulties of a practical nature due to the extremely high temperature of their treatment, they do not present the desired stability when the temperature exceeds 600; in fact, not 30 only an accidental excess of temperature beyond the regulated value, but even prolonged ex osure to this temperature produce a gradua disappearance of the initial hardness and a progressive diminution of resistance. Fi- 5 nally, they are very oxidizable.

In addition, the invention of gas motors, gas turbines and other thermal machines intended to act above the temperature of red heat, and the discovery of chemical synthetic 60 processes using at the same time high temperatures and high pressures, render the realization of a metal possessing certain qualities at' high temperature extremely desirable.

The present application, which is a divi- 4 sion of my apphcation, Serial No. 265,985, filed December 9, 1918, concerns an alloy of iron, nickel, chromium and molybdenum, and including, perhaps, tungsten or vanadium, cobalt and titanium, easy to obtain in large quantities and capable of being moulded, or otherwise, forged, rolled, wire drawn, worked, without difliculty, possessing at the tem erature of 800 a resistance almost equivalent to that of cold iron, non-fragile,

1922. Serial No. 535,044.

practically inoxidizable at high temperatures, even in a very oxidizing temperature, and at the same time possessing properties which are strictly reversible; by this term I understand that the properties at. a given temperature depend solely on that temperature and in no way on the preceding temperatures that havebeen obtained, nor on an exposure more or less long to the temperature used. The alloy may contain, for example:

Per cent. Nickel 60 to 70 Chromium 10 to Molybdenum 1 to 3 Manganese 1 to 2 Carbon 0.3 to 0.6

Iron forming the remainder.

Certain variations in the composition may fer on the alloy of iron and nickel a very high resistance when heated: I can obtain easily 25 to 35 kgs. per sq. mm. with an elastic limit of 20 to 30 kgs. and a coeflicient of elongation of 40 per cent at a temperature of 800, while still preserving a total absence of fragility. These additional elements also render the alloy extremely resistant to the attack of acid vapours, as well as of hot oxidizing and moist gases. This chemical unalterability is of the greatest importance for all applications, since it not only ensures the metal against corrosion, but also ensures the preservation of the initial mechanical properties, in contra-distinction to that whichtakes place with carbon steels which, when heated for a long time in an atmosphere rich in hydrogen, finally become decarburized and lose their solidity.

This alloy is certainly very suitable for the manufacture of gas turbines or for receptacles, employed in chemical industry, for reactions which take place at high temperathre and at high pressure and which produce corrosive gases or other substances.

Having thus described the nature of the said inventionand the best means I know of a carrying the same into practical vefiect, I

claim:

A high nickel ferrous alloy containing nickel, 60 to 70 er cent, chromium, 10 to 15 per cent, molyb enum, 1 to 3 per cent, manganese 1 t0 2 per cent and carbon, 0.3 to 0.6 per cent, such alloy having at elevated temperatures great mechanical resistance to chemical agents and susceptible of retaining indefinitely its initial properties, notwithstanding prolonged service.

In testimony whereof I have signed this specification.

PIERRE GIRIN.