Government of the United States of America, As Represented by the Secretary of Commerce

Christopher N McCowan

Thomas A Siewert

An alloy comprising nickel, chromium, molybdenum, manganese, nitrogen and on in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in a concentration of from about 0.1 to about 0.2% of the alloy in weight percent. The weld metals prepared from the alloys of the present invention possess superior properties as compared to other stainless steels. These properties include inter alia a superior tearing modulus, fracture toughness, and yield strength, even at cryogenic temperatures. The present invention further provides a method for welding a metal part which is intended for exposure to cryogenic temperatures comprising welding the metal part using a welding electrode comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in the electrode in a concentration of from about 0.1 to about 0.2% of the electrode in weight percent. Preferably, the welding comprises gas metal arc welding, wherein shielding gas used during welding contains no more than about 2% oxygen by volume.

Method for welding cryogenic alloys

An alloy comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in a concentration of from about 0.1 to about 0.2% of the alloy in weight percent. The weld metals prepared from the alloys of the present invention possess superior properties as compared to other stainless steels. These properties include inter alia a superior tearing modulus, fracture toughness, and yield strength, even at cryogenic temperatures. The present invention further provides a method for welding a metal part which is intended for exposure to cryogenic temperatures comprising welding the metal part using a welding electrode comprising nickel, chromium, molybdenum, manganese, nitrogen and iron in amounts such that a weld metal formed therefrom is austenitic, wherein nitrogen is present in the electrode in a concentration of from about 0.1 to about 0.2% of the electrode in weight percent. Preferably, the welding comprises gas metal arc welding, wherein shielding gas used during welding contains no more than about 2% oxygen by volume.

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Boulder, CO, United States of America

Christopher N McCowan