Austenitic paramagnetic corrosion resistant material

Abstract

The alloys of the present invention provide austenitic, paramagnetic materials with high strength, ductility, and yield strength and good corrosion resistance in media with high chloride concentrations. Alloys of the present invention were developed because of the need by oilfield industries for superior materials. The alloys of the present invention may be used in drilling string components, and the tests performed demonstrate that such alloys exhibit properties balanced for very high yield strength, magnetic permeability, and corrosion resistance superior in every respect to presently available paramagnetic, high strength, corrosion resistant austenitic stainless steels.

1 . An austenitic, paramagnetic material with high strength, ductility, and yield strength and good corrosion resistance in media with high chloride concentrations, comprising (in wt-%): 
 up to about 0.035 carbon;    about 0.25 to about 0.75 silicon;    about 22.0 to about 25.0 manganese;    about 0.75 to about 1.00 nitrogen;    about 19.0 to about 23.0 chromium;    about 2.70 to about 5.00 nickel;    about 1.35 to about 2.00 molybdenum;    about 0.35 to about 1.00 copper;    about 0.002 to about 0.006 boron;    up to about 0.01 sulfur;    up to about 0.030 phosphorous; and    substantially no ferrite content.    
     
     
         2 . The material according to  claim 1 , wherein the material comprises about 2.70 to about 4.25 wt-% nickel.  
     
     
         3 . The material according to  claim 2 , wherein the material comprises about 2.75 to about 4.20 wt-% nickel.  
     
     
         4 . The material according to  claim 3 , wherein the material comprises about 3.50 to about 4.20 nickel.  
     
     
         5 . The material according to  claim 1 , wherein the material comprises about 0.35 to about 0.85 wt-% copper.  
     
     
         6 . The material according to  claim 5 , wherein the material comprises about 0.35 to about 0.75 wt-% copper.  
     
     
         7 . The material according  claim 6 , wherein the material comprises about 0.50 to about 0.75 copper.  
     
     
         8 . The material according to  claim 1 , wherein the material comprises (in wt-%): 
 up to about 0.030 carbon;    about 0.25 to about 0.45 silicon;    about 22.0 to about 23.0 manganese;    about 0.75 to about 0.90 nitrogen;    about 19.0 to about 20.0 chromium;    about 2.70 to about 4.25 nickel;    about 1.40 to about 1.80 molybdenum;    about 0.35 to about 0.75 copper;    about 0.003 to about 0.006 boron;    up to about 0.006 sulfur; and    up to about 0.025 phosphorous.    
     
     
         9 . The material according to  claim 8 , wherein the material comprises (in wt-%): 
 up to about 0.028 carbon;    about 0.30 to about 0.45 silicon;    about 22.0 to about 23.0 manganese;    about 0.78 to about 0.90 nitrogen;    about 19.0 to about 20.0 chromium;    about 3.50 to about 4.20 nickel;    about 1.40 to about 1.75 molybdenum;    about 0.50 to about 0.75 copper;    about 0.003 to about 0.006 boron;    up to about 0.003 sulfur; and    up to about 0.020 phosphorous.    
     
     
         10 . The material according to  claim 1 , wherein the material has a PREN value of greater than about 37.  
     
     
         11 . The material according to  claim 10 , wherein the material has a PREN value of greater than about 37 and less than about 39.  
     
     
         12 . The material according to  claim 1 , wherein the material has a yield strength at 0.2% offset of greater than about 140 ksi.  
     
     
         13 . The material according to  claim 12 , wherein the material has a yield strength of greater than about 140 and less than about 190 ksi.  
     
     
         14 . The material according to  claim 1 , wherein the material has a PREN value of greater than about 37 and a yield strength at 0.2% offset of greater than about 140 ksi.  
     
     
         15 . The material according to  claim 14 , wherein the material has a PREN value of greater than about 37 and less than about 39 and a yield strength at 0.2% offset of greater than about 140 and less than about 190 ksi.