High strength, corrosion resistant austenitic alloys

Abstract

An austenitic alloy may generally comprise, in weight percentages based on total alloy weight: up to 0.2 carbon; greater than 2.0 up to 20.0 manganese; 0.1 to 1.0 silicon; 14.0 to 28.0 chromium; 15.0 to 38.0 nickel; 2.0 to 9.0 molybdenum; 0.1 to 3.0 copper; 0.08 to 0.9 nitrogen; 0.1 to 5.0 tungsten; 0.5 to 5.0 cobalt; up to 1.0 titanium; up to 0.05 boron; up to 0.05 phosphorus; up to 0.05 sulfur; iron; and incidental impurities.

What is claimed is: 
     
         1 . An austenitic alloy comprising, in weight percentages:
 up to 0.2 carbon;   greater than 2.0 up to 20.0 manganese;   0.1 to 1.0 silicon;   14.0 to 28.0 chromium;   15.0 to 38.0 nickel;   2.0 to 9.0 molybdenum;   0.1 to 3.0 copper;   0.08 to 0.9 nitrogen;   0.1 to 5.0 tungsten;   0.5 to 5.0 cobalt;   up to 1.0 titanium;   up to 0.05 boron;   up to 0.05 phosphorus;   up to 0.05 sulfur;   iron; and   incidental impurities.   
     
     
         2 . The alloy of  claim 1 , wherein the manganese is greater than 2.0 up to 10.0. 
     
     
         3 . The alloy of  claim 2 , further comprising at least one of columbium and tantalum, wherein a combined weight percentage of columbium and tantalum is up to 0.3. 
     
     
         4 . The alloy of  claim 2 , further comprising up to 0.2 weight percent vanadium. 
     
     
         5 . The alloy of  claim 2 , further comprising up to 0.1 weight percent aluminum. 
     
     
         6 . The alloy of  claim 2 , further comprising at least one of cerium and lanthanum, wherein a combined weight percentage of cerium and lanthanum is no greater than 0.1. 
     
     
         7 . The alloy of  claim 2 , further comprising up to 0.5 weight percent ruthenium. 
     
     
         8 . The alloy of  claim 2 , further comprising up to 0.6 weight percent zirconium. 
     
     
         9 . The alloy of  claim 2 , wherein the iron is up to 60 weight percent. 
     
     
         10 . The alloy of  claim 2 , comprising a cobalt/tungsten ratio, based on weight percentages, from 2:1 to 4:1. 
     
     
         11 . The alloy of  claim 2 , having a PREN 16  value greater than 40. 
     
     
         12 . The alloy of  claim 2 , having a PREN 16  value in the range of 40 to 60. 
     
     
         13 . The alloy of  claim 2 , wherein the alloy is non-magnetic. 
     
     
         14 . The alloy of  claim 2 , having a magnetic permeability value less than 1.01. 
     
     
         15 . The alloy of  claim 2 , having an ultimate tensile strength of at least 110 ksi, a yield strength of at least 50 ksi, and a percent elongation of at least 15%. 
     
     
         16 . The alloy of  claim 2 , having an ultimate tensile strength in the range of 90 ksi to 150 ksi, a yield strength in the range of 50 ksi to 120 ksi, and a percent elongation in the range of 20% to 65%. 
     
     
         17 . The alloy of  claim 2 , having an ultimate tensile strength in the range of 100 ksi to 240 ksi, a yield strength in the range of 110 ksi to 220 ksi, and a percent elongation in the range of 15% to 30%. 
     
     
         18 . The alloy of  claim 2 , wherein the nitrogen is 0.1 to 0.55 weight percent. 
     
     
         19 . The alloy of  claim 2 , wherein the nitrogen is 0.2 to 0.5 weight percent. 
     
     
         20 . The alloy of  claim 2 , having a critical pitting temperature of at least 45° C. 
     
     
         21 . The alloy of  claim 1  comprising, in weight percentages based on total alloy weight:
 up to 0.05 carbon; 
 greater than 2.0 up to 9.0 manganese; 
 0.1 to 1.0 silicon; 
 18.0 to 26.0 chromium; 
 19.0 to 37.0 nickel; 
 3.0 to 7.0 molybdenum; 
 4 to 2.5 copper; 
 0.1 to 0.55 nitrogen; 
 0.2 to 3.0 tungsten; 
 0.8 to 3.5 cobalt; 
 up to 0.6 titanium; 
 a combined weight percentage of columbium and tantalum no greater than 0.3; 
 up to 0.2 vanadium; 
 up to 0.1 aluminum; 
 up to 0.05 boron; 
 up to 0.05 phosphorus; 
 up to 0.05 sulfur; 
 iron; and 
 incidental impurities. 
 
     
     
         22 . The alloy of  claim 21 , wherein the manganese is greater than 2.0 up to 8.0 weight percent. 
     
     
         23 . The alloy of  claim 21 , wherein the chromium is 19.0 to 25.0 weight percent. 
     
     
         24 . The alloy of  claim 21 , wherein the nickel is 20.0 to 35.0 weight percent. 
     
     
         25 . The alloy of  claim 21 , wherein the molybdenum is 3.0 to 6.5 weight percent. 
     
     
         26 . The alloy of  claim 21 , wherein the copper is 0.5 to 2.0 weight percent. 
     
     
         27 . The alloy of  claim 21 , wherein the nitrogen is 0.2 to 0.5 weight percent. 
     
     
         28 . The alloy of  claim 21 , wherein the tungsten is 0.3 to 2.5 weight percent. 
     
     
         29 . The alloy of  claim 21 , wherein the cobalt is 1.0 to 3.5 weight percent. 
     
     
         30 . The alloy of  claim 21 , wherein the iron is 20 to 50 weight percent. 
     
     
         31 . The alloy of  claim 1  comprising, in weight percentages based on total alloy weight:
 up to 0.05 carbon; 
 greater than 2.0 up to 8.0 manganese; 
 0.1 to 0.5 silicon; 
 19.0 to 25.0 chromium; 
 20.0 to 35.0 nickel; 
 3.0 to 6.5 molybdenum; 
 0.5 to 2.0 copper; 
 0.2 to 0.5 nitrogen; 
 0.3 to 2.5 tungsten; 
 1.0 to 3.5 cobalt; 
 up to 0.6 titanium; 
 a combined weight percentage of columbium and tantalum no greater than 0.3; 
 up to 0.2 vanadium; 
 up to 0.1 aluminum; 
 up to 0.05 boron; 
 up to 0.05 phosphorus; 
 up to 0.05 sulfur; 
 iron; 
 trace elements; and 
 incidental impurities. 
 
     
     
         32 . The alloy of  claim 31 , wherein the manganese is greater than 2.0 up to 6.0 weight percent. 
     
     
         33 . The alloy of  claim 31 , wherein the chromium is 20.0 to 22.0 weight percent. 
     
     
         34 . The alloy of  claim 31 , wherein the molybdenum is 6.0 to 6.5 weight percent. 
     
     
         35 . The alloy of  claim 31 , wherein the iron is 40 to 45 weight percent.