A corrosion resistant austenitic stainless steel alloy and articles made therefrom consisting essentially in weight percent of in which nitrogen ranges from a minimum of 0.15 w/o to no more than the amount that can be retained in solid solution, the balance being essentially iron, and the elements being balanced so that cold rolled annealed specimens prepared with a crevice and tested in accordance with ASTM G48-76 in 10 w/o FeCl.sub.3 .multidot.6H.sub.2 O at 50.degree. C. for 72 hours have a weight loss of less than 0.3 gram. An embodiment that is particularly well suited for making autogeneously welded articles, e.g. tubing, for uses requiring exposure to brackish water consists essentially in weight percent of: ______________________________________ (w/o) ______________________________________ C 0.06-0.08 Mn 4-6 Si 0.6 Max. Cr 20.5-21.5 Ni 14.5-15.5 Mo 4.8-5.4 B 0.0015-0.0035 Al 0.5 Max. N 0.20-0.25 ______________________________________ in which the balance is essentially iron.
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.degree. C. to 1540.degree. 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.degree. C. to 1495.degree. C., and subsequently subjecting the castings or metal to a solution heat-treatment at 1400.degree. C. to 1160.degree. C. A further aspect of the invention is a high-strength, austenitic stainless steel characterised by the following chemical composition by wt %: A still further aspect of the invention is a weld rod or wire or a weld metal of the composition above definded.
The present invention provides non-magnetic stainless steel which is used as materials for small parts in precision machines and electronic equipment. The non-magnetic stainless steel consists of an iron-based alloy containing 9 to 22% by weight of nickel, 12 to 26% by weight of chromiun, the balance of iron and inevitable impurities. The martensitic area ratio of the iron-based alloy structure is not more than 20%. The stainless steel exhibits excellent workability and is suitable as a raw material for TV electron gun parts and small gears which are formed by strong working such as blanking or the like.
An austenitic stainless steel having good corrosion resistance, particularly in chloride environments; this is achieved by the use of a rare earth element, preferably lanthanum, singly or in combination with nitrogen, along with nickel and molybdenum at relatively low levels for an austenitic stainless steel. The composition includes 15 to 25% chromium, greater than 16 to 25% nickel, 3 to 7% molybdenum, with a rare earth element consisting of lanthanum within the range of 0.005 to 0.05% in combination with 0.1 to 0.5% nitrogen.
High-strength pipes are manufactured from cold-deformed carbon steel or alloyed steel for use in acid environment, in which the H.sub.2 S partial pressure in gaseous phase may exceed 300 Pa or in which the H.sub.2 S content in liquid phase may have a corresponding equilibrium pressure and/or in which CO.sub.2 and other acidifying substances may be present. The weight % composition of the steel is preferably: C 0-1.20% Si 0-1.0% Mn 0-3.0% Cr 0-2.0% Ni 0-1.0% Mo 0-1.0% Cu 0-1.0% V 0-0.3% Nb 0-0.2% Ca 0-0.05% Fe+incidental ingredients and impurities up to 100%.
A method is provided for producing a nickel-chromium-molybdenum austenitic stainless steel in heavy section sizes and in welded article form substantially free of second phase precipitation from annealing and welding temperatures. The method includes providing nitrogen additions and annealing at temperatures of less than 2100.degree. F., preferably less than 2000.degree. F.
