Methods of manufacturing divided blades of turbomachines by additive manufacturing

Abstract

The method is used for manufacturing a turbomachine blade that comprises an airfoil portion and is divided into two parts at an intermediate region of the airfoil portion; each of the two parts of the airfoil portion is obtained by additive manufacturing; the two parts are joined by brazing.

What is claimed is: 
     
         1 . A method of manufacturing a turbomachine blade comprising an airfoil portion and being divided into two parts (P 1 , P 2 ) at an intermediate region of the airfoil portion, wherein each of said two parts (P 1 , P 2 ) of said airfoil portion is obtained by additive manufacturing, and wherein said two parts are joined by brazing. 
     
     
         2 . The manufacturing method of  claim 1 , wherein said two parts (P 1 , P 2 ) are directly brazed together. 
     
     
         3 . The manufacturing method of  claim 1 , wherein leading edge portions and intermediate portions of said two parts (P 1 , P 2 ) are joined by brazing and trailing edge portions of said two parts (P 1 , P 2 ) are joined through one or more dowel pins. 
     
     
         4 . The manufacturing method of  claim 1 , wherein the turbomachine blade comprises a root portion adjacent to a first part (P 1 ) of said two parts (P 1 , P 2 ) of the airfoil portion and a shroud portion adjacent to a second part (P 2 ) of said two parts (P 1 , P 2 ) of the airfoil portion, wherein said root portion and said first part (P 1 ) are obtained in a single piece by additive manufacturing and wherein said shroud portion and said second part (P 2 ) are obtained in a single piece by additive manufacturing. 
     
     
         5 . The manufacturing method of  claim 1 , wherein said airfoil portion extends longitudinally for a length and has a first end region and a second end region, wherein said airfoil portion has at least one internal cavity extending along said length. 
     
     
         6 . The manufacturing method of  claim 5 , wherein the turbomachine blade is associated to a longitudinal axis, and wherein said airfoil portion is divided into two parts by a plane transversal to said longitudinal axis, said plane transversal and said longitudinal axis forming an angle greater than 0° and smaller than 45°. 
     
     
         7 . The manufacturing method of  claim 5 , wherein at least one of said parts of said airfoil portion has at least one hole at said intermediate region, and at least one dowel pin is inserted into said at least one hole. 
     
     
         8 . The manufacturing method of  claim 5 , wherein said at least two parts of said airfoil portion are joined together by a push fit, wherein a first part of said parts of said airfoil portion has a male-type lipped rim, and wherein a second part of said parts of said airfoil portion has a female-type lipped rim, so that a female-male connection between said parts of said airfoil portion is established. 
     
     
         9 . The manufacturing method of  claim 5 , wherein a cross-section of said at least one internal cavity is reduced at said intermediate region of said airfoil portion. 
     
     
         10 . The manufacturing method of  claim 5  being arranged as a stator blade of an axial flow steam turbine, wherein said airfoil portion has holes and/or slots extending from an airfoil surface to said internal cavity, wherein one or more of said at least two parts is made of metallic material.