Method of surface treatment for dovetail in gas turbine engine fan blade

Abstract

A method of surface treating a dovetail in a blade includes the steps of providing a burnishing operation along circumferential sides of the dovetail. Next, shot peening is provided at axial ends of the dovetail. A fan blade made by the method is also claimed.

What is claimed is: 
     
         1 . A method of surface treating a dovetail in a blade comprises the steps of:
 providing a burnishing operation along circumferential sides of said dovetail; and   then providing shot peening to axial ends of said dovetail.   
     
     
         2 . The method as set forth in  claim 1 , wherein said burnishing operation is low plasticity burnishing. 
     
     
         3 . The method as set forth in  claim 2 , wherein said burnishing technique includes a body which is brought into contact with the circumferential sides of said dovetail, said body being controlled by a position control and a pressure control to apply a desired stress distribution and compressive load within the dovetail along said circumferential sides. 
     
     
         4 . The method as set forth in  claim 1 , wherein the entire dovetail is subject to a shot peening process prior to the burnishing operation. 
     
     
         5 . The method as set forth in  claim 1 , wherein said axial ends are not regular surfaces, but have complex curved shapes 
     
     
         6 . The method as set forth in  claim 5 , wherein said circumferential sides have a more regular shape. 
     
     
         7 . The method as set forth in  claim 1 , wherein said blade is for use in a gas turbine engine. 
     
     
         8 . The method as set forth in  claim 7 , wherein said blade is a fan blade. 
     
     
         9 . A blade comprising:
 an airfoil extending radially outwardly from a dovetail, the airfoil having a leading edge and a trailing edge; and   said dovetail having circumferential sides, and axial ends, with said circumferential sides being surface treated by a burnishing operation, and said axial ends being surface treated by shop peening; and   said axial ends having complex curved shapes, and said circumferential sides having generally regular shapes along an axial length.   
     
     
         10 . The blade as set forth in  claim 9 , wherein said blade is for use in a gas turbine engine. 
     
     
         11 . The blade as set forth in  claim 10 , wherein said blade is a fan blade.