Stainless steels

Abstract

This invention relates to a high-strength, austenitic, stainless steel, and to a method of its production. A method of producing a high-strength, austenitic, stainless steel characterised by air-melting a feedstock of super austenitic stainless steel, introducing nitrogen at 1520° C. to 1540° C. by way of electrolytic manganese containing 6 wt % nitrogen, then low carbon ferro-chrome, adding boron when the other two alloys have been fully absorbed into the molten bath, allowing the bath to cool, casting the metal at 1480° C. to 1495° C., and subsequently subjecting the castings or metal to a solution heat-treatment at 1400° C. to 1160° C. A further aspect of the invention is a high-strength, austenitic stainless steel characterised by the following chemical composition by wt %: Carbon 0.005 to 0.030 Silicon 0.03 to 1.00 Manganese 3.50 to 9.00 Phosphorous less than 0.025 Sulphur less than 0.01 Chromium 23.00 to 26.00 Molybdenum 4.00 to 6.00 Nickel 15.00 to 18.00 Nitrogen 0.50 to 1.10 Balance Fe A still further aspect of the invention is a weld rod or wire or a weld metal of the composition above definded.

Dependencies are inferred from the claim text.