Martensitic alloy component and process of forming a martensitic alloy component

Abstract

A reduced nickel-chromium alloy component having by weight about 0.38% to about 0.43% C, about 0.15% to about 0.30% Si, about 1.00% to about 1.25% Mn, about 0.75% to about 0.90% Ni, about 1.00% to about 1.30% Cr, about 0.25% to about 0.35% Mo, about 0.05% to about 0.12% V, up to about 0.015% S, up to about 0.015% P, up to about 0.15% Cu, and balance iron and incidental impurities. The component has a hardenability corresponding to an ideal diameter of greater than about 10 inches.

What is claimed is: 
     
         1 . A martensitic alloy component, comprising by weight:
 about 0.38% to about 0.43% C;   about 0.15% to about 0.30% Si;   about 1.00% to about 1.25% Mn;   about 0.75% to about 0.90% Ni;   about 1.00% to about 1.30% Cr;   about 0.25% to about 0.35% Mo;   about 0.05% to about 0.12% V;   up to about 0.015% S;   up to about 0.015% P;   up to about 0.15% Cu; and   balance iron and incidental impurities;   wherein the component has a hardenability corresponding to an ideal diameter of greater than about 10 inches.   
     
     
         2 . The martensitic alloy component of  claim 1 , wherein the component comprises about 1.05 to about 1.25% Mn. 
     
     
         3 . The martensitic alloy component of  claim 1 , wherein the component comprises about 1.15% Mn. 
     
     
         4 . The martensitic alloy component of  claim 1 , wherein the component has a hardenability corresponding to an ideal diameter of from about 10 inches to about 18 inches. 
     
     
         5 . The martensitic alloy component of  claim 2 , wherein the component has a hardenability corresponding to an ideal diameter of from about 11 inches to about 12 inches. 
     
     
         6 . The martensitic alloy component of  claim 3 , wherein the component has a hardenability corresponding to an ideal diameter of about 11.4 inches. 
     
     
         7 . The martensitic alloy component of  claim 2 , wherein the component has a hardenability corresponding to an ideal diameter of from about 13 inches to about 14 inches. 
     
     
         8 . The martensitic alloy component of  claim 5 , wherein the component has a hardenability corresponding to an ideal diameter of about 13.3 inches. 
     
     
         9 . The martensitic alloy component of  claim 1 , further comprising a fracture apparent transition temperature at a surface of the component of less than −40° C. 
     
     
         10 . The martensitic alloy component of  claim 1 , further comprising a fracture apparent transition temperature at a maximum thickness of the component of less than 30 ° C. 
     
     
         11 . The martensitic alloy component of  claim 1 , wherein the martensitic alloy component has a average grain size of less than about 62 μm. 
     
     
         12 . The martensitic alloy component of  claim 1 , wherein the martensitic alloy component has a yield strength at a surface of the component of greater than about 650 MPa. 
     
     
         13 . The martensitic alloy component of  claim 1 , wherein the martensitic alloy component has a tensile strength at a surface of the component of between about 800 and about 1,000 MPa. 
     
     
         14 . The martensitic alloy component of  claim 1 , wherein the component has a thickness of greater than 20 inches. 
     
     
         15 . The martensitic alloy component of  claim 1 , wherein the component is a wind turbine shaft. 
     
     
         16 . The martensitic alloy component of  claim 13 , wherein the wind turbine shaft has at least one solid segment. 
     
     
         17 . The martensitic alloy component of  claim 13 , wherein the wind turbine shaft has at least one hollow segment. 
     
     
         18 . A process of forming a martensitic alloy component, the process comprising:
 forging an alloy comprising by weight:   about 0.38% to about 0.43% C;   about 0.15% to about 0.30% Si;   about 1.00% to about 1.25% Mn;   about 0.75% to about 0.90% Ni;   about 1.00% to about 1.30% Cr;   about 0.25% to about 0.35% Mo;   about 0.05% to about 0.12% V;   up to about 0.015% S;   up to about 0.015% P;   up to about 0.15% Cu; and   balance iron and incidental impurities;   austenitizing the forged alloy;   quenching the austenitized alloy; and   tempering the quenched alloy;   wherein the component has a hardenability corresponding to an ideal diameter of greater than about 10 inches.   
     
     
         19 . The process of  claim 18 , wherein the component has a thickness of greater than 20 inches. 
     
     
         20 . The process of  claim 18 , wherein the component is a wind turbine shaft.