Alloy compositions and articles formed of such compositions

Abstract

Described herein are compositions, and more particularly to alloy compositions and articles formed with the alloy compositions. The alloy compositions are broadly applicable in applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite, and/or improved rupture ductility.

What is claimed is: 
     
         1 . A composition comprising:
 from about 10 wt % to about 11 wt % chromium;   no more than about 0.030 wt % aluminum;   from about 0.08 wt % to about 0.20 wt % carbon;   from about 0.10 wt % to about 0.60 wt % silicon;   from about 0.05 wt % to about 0.40 wt % vanadium;   from about 0.01 wt % to about 0.10 wt % titanium;   no more than about 5 wt % of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and   balance iron and residual elements.   
     
     
         2 . The composition of  claim 1 , wherein the composition comprises from about 10.25 wt % to about 11 wt % chromium. 
     
     
         3 . The composition of  claim 1 , wherein the composition comprises no more than 0.015 wt % aluminum. 
     
     
         4 . The composition of  claim 1 , wherein the composition comprises from about 0.12 wt % to about 0.18 wt % carbon. 
     
     
         5 . The composition of  claim 1 , wherein the composition comprises from about 0.20 wt % to about 0.40 wt % silicon. 
     
     
         6 . The composition of  claim 1 , wherein the composition comprises from about 0.10 wt % to about 0.30 wt % vanadium. 
     
     
         7 . The composition of  claim 1 , wherein the composition comprises from about 0.015 wt % to about 0.060 wt % titanium. 
     
     
         8 . The composition of  claim 1 , comprising:
 from about 10.25 wt % to about 11 wt % chromium;   no more than about 0.015 wt % aluminum;   from about 0.12 wt % to about 0.18 wt % carbon;   from about 0.20 wt % to about 0.40 wt % silicon;   from about 0.10 wt % to about 0.30 wt % vanadium;   from about 0.015 wt % to about 0.060 wt % titanium;   no more than about 5 wt % of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and   balance iron and residual elements.   
     
     
         9 . The composition of  claim 1 , further comprising:
 from about 0.10 wt % to about 1.0 wt % manganese; and/or   from about 0.40 wt % to about 1.2 wt % molybdenum.   
     
     
         10 . The composition of  claim 1 , further comprising:
 from about 0.50 wt % to about 1.0 wt % manganese; and/or   from about 0.60 wt % to about 0.80 wt % molybdenum.   
     
     
         11 . The composition of  claim 1 , wherein the composition has a freezing range less than about 200° F. 
     
     
         12 . The composition of  claim 1 , wherein the composition has a freezing range less than about 175° F. 
     
     
         13 . The composition of  claim 1 , wherein the composition has a martensite start temperature in a range of from about 450° F. to about 550° F. 
     
     
         14 . The composition of  claim 1 , wherein the composition has a martensite 90% temperature in a range of from about 250° F. to about 350° F. 
     
     
         15 . The composition of  claim 1 , wherein the composition is a wrought composition and/or a cast composition. 
     
     
         16 . An article comprising a composition, the composition comprising:
 from about 10 wt % to about 11 wt % chromium;   no more than about 0.030 wt % aluminum;   from about 0.08 wt % to about 0.20 wt % carbon;   from about 0.10 wt % to about 0.60 wt % silicon;   from about 0.05 wt % to about 0.40 wt % vanadium;   from about 0.01 wt % to about 0.10 wt % titanium;   no more than about 5 wt % of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and   balance iron and residual elements.   
     
     
         17 . The article of  claim 16 , wherein the article is a component of a turbine selected from the group consisting of an inner casing for an in-case steam turbine high pressure rotor, an inner casing for an in-case steam turbine intermediate pressure rotor, an outer casing for an in-case steam turbine high pressure rotor, an outer casing for an in-case steam turbine intermediate pressure rotor, a packing head, a diaphragm casing, and a combination thereof. 
     
     
         18 . The article of  claim 16 , wherein the article is a component of a turbine selected from the group consisting of a nozzle, a shroud, a splash plate, a combustor component, a diffuser case, an inner diffuser case, a compressor case, an inner compressor case, a splitter, an inner barrel, a turbine shell, compressor blades, compressor vanes, guide vanes, retaining rings, and a combination thereof. 
     
     
         19 . The article of  claim 16 , wherein the composition comprises:
 from about 10.25 wt % to about 11 wt % chromium;   no more than about 0.015 wt % aluminum;   from about 0.12 wt % to about 0.18 wt % carbon;   from about 0.20 wt % to about 0.40 wt % silicon;   from about 0.10 wt % to about 0.30 wt % vanadium;   from about 0.015 wt % to about 0.060 wt % titanium;   no more than about 5 wt % of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and   balance iron and residual elements.   
     
     
         20 . The article of  claim 16 , wherein the composition further comprises:
 from about 0.10 wt % to about 1.0 wt % manganese; and/or   from about 0.40 wt % to about 1.2 wt % molybdenum.