The Garrett Corporation

Allegheny Ludlum Industries, Inc.

Lynn E Kindlimann

Matthew J Pohlman

Albert G Hartline, Iii

Through-nitrided light gage ferritic stainless steels having a dispersion of metal-nitride particles at an interparticle spacing of less than about 10 microns. The resulting material has substantially improved strength at room and elevated temperatures over conventional ferritic stainless steels, exhibits ductility markedly above that commonly associated with nitrided articles, and is stronger than conventional 18Cr-8Ni austenitic stainless steel (T-304) for prolonged service above about 1400.degree. F. The nitriding is accomplished with atomic nitrogen at 1500.degree.-1800.degree. F. followed by heating to above 1800.degree. F. in a non-oxidizing atmosphere to remove excess nitrides.

Dispersion strengthened ferritic stainless steel

A method of internally nitriding and brazing assemblies having iron based components to which titanium has been internally added prior to casting. A brazed assembly includes iron based components to which titanium is added prior to casting and is dispersion strengthened by nitridation to form an array of titanium nitride particles.

Nitridation and brazing of assemblies with titanium-containing iron

An economical brazing alloy composition includes high amounts of iron. A brazed assembly includes iron-based brazing alloys.

Iron-based brazing alloy compositions and brazed assemblies with iron

A method of internally nitriding and thereby strengthening cobalt-base superalloys having at least 33% cobalt, up to 0.15% carbon, no more than 25% nickel and from 1 to 3% of nitride forming elements from the group consisting of titanium, vanadium, niobium, tantalum and zirconium. The method comprises the steps of: heating the cobalt-base alloy at a temperature of from 1600.degree. to 2500.degree. F in a nitrogen-bearing atmosphere substantially free of moisture and oxygen, and diffusing nitrogen from said atmosphere into and throughout said alloy for a period of time sufficient to form nitrides having an interparticle spacing of less than 10 microns.

Internal nitridation of cobalt-base superalloys

An austenitic alloy containing, in weight percent, from 36 to 54% nickel, up to 12% cobalt, up to 15% chromium, up to 10% molybdenum, from 1 to 3.75% titanium, up to 2% aluminum, up to 0.1% carbon, up to 2% manganese, up to 1% silicon, up to 0.05% boron, balance essentially iron; wherein the percentage of iron is at least 24%; wherein the percentage of nickel plus the percentage of cobalt and the percentage of chromium plus the percentage of molybdenum corresponds to the area ACEFA in FIG. 3; and wherein the percentage of nickel is the effective nickel in accordance with the equation:

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Woodland Hills, CA, United States of America

Lynn E Kindlimann