Austenite alloy tubes having excellent high temperature vapor oxidation resistant property
AssigneeNippon Kokan Kabushiki Kaisha
InventorsTakahiro Kanero, Yusuke Minami
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Abstract
The austenite alloy tube has a composition of 15.about.26% of Cr, 8.about.35% of Ni, 1.0% or less of Si, 2.0% or less of Mn and less than 0.25% of N and the balance of iron and impurities. The nitrogen content on the inner surface of the tube is at least 0.25%. If desired, one or more of 0.6% or less of Ti, 0.6% or less of Al, 3.0% or less of Mo and 1.0% or less of Nb may be incorporated.
Claims6
An austenite alloy tube having excellent high temperature steam oxidation resistant properties having a composition comprising 15 to 26% by weight of chromium, 8 to 35% nickel, silicon in an amount up to 1%, manganese in an amount up to 2%, said tube having an average nitrogen content of less than 0.25%, and having a nitrogen content of 0.25% or higher on the inner surface of said tube, said inner surface having been nitrided to provide said higher nitrogen content, and the balance of said tube being iron and impurities.
Dependencies are inferred from the claim text.