Heavy austempered ductile iron components

Abstract

A component for wind turbines includes cast austempered ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.06 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur. The component is preferably a drive shaft or gearbox component having a mass of more than about 3 tons. A method of manufacturing the component is also provided.

1 . A component comprising:
 cast austempered ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.05 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur wherein the component comprises a mass of more than about 3 tons.   
     
     
         2 . The component of  claim 1 , wherein the component comprises a mass of more than about 6 tons. 
     
     
         3 . The component of  claim 1 , wherein the component comprises a drive shaft. 
     
     
         4 . The component of  claim 1 , wherein the component comprises a heavy gearbox component. 
     
     
         5 . The component of  claim 1 , wherein the austempered ductile iron comprises acicular ferrite and austenite. 
     
     
         6 . A method of manufacturing a component, the method comprising:
 melting ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.06 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur;   casting the component;   austenitizing the component;   quenching the component; and   austempering the component.   
     
     
         7 . The method of  claim 6 , wherein the quenching comprises immersing the component in a medium kept at a temperature of from about 230 to about 400° C. 
     
     
         8 . The method of  claim 6 , further comprising:
 machining the component.   
     
     
         9 . The method of  claim 6 , wherein the component comprises a mass of more than about 3 tons. 
     
     
         10 . The method of  claim 6 , wherein the component comprises a mass of more than about 6 tons. 
     
     
         11 . The method of  claim 6 , wherein the component comprises a wind turbine shaft. 
     
     
         12 . The method of  claim 6 , wherein the component comprises a gearbox component. 
     
     
         13 . The method of  claim 6 , wherein the austenitizing comprises holding the component at a temperature in a range of about 815° C. to about 985° C. for a time sufficient to convert a matrix to austenite 
     
     
         14 . A wind turbine drive shaft comprising:
 cast austempered ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.06 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur wherein the drive shaft comprises a mass of more than about 3 tons.   
     
     
         15 . The wind turbine drive shaft of  claim 14 , wherein the drive shaft comprises a mass of more than about 6 tons. 
     
     
         16 . The wind turbine drive shaft of  claim 14 , wherein the austempered ductile iron comprises acicular ferrite and austenite.