Welding method of turbine diaphragm

A method of welding a turbine diaphragm, the method comprising the steps of:

• preparing spacers with a plurality of annularly arranged nozzle blades, fitting respective ends of each of the plurality of nozzle blades into corresponding holes provided in the spacers, and arc-welding the respective blades and spacers to join each of the blades to the spacers;
• finishing the welded portions of the spacers to form annular joining faces;
• preparing inner and outer wheels so that the inner wheel has an annular outer face to be welded and the outer wheel has an annular inner face to be welded;
• positioning the spacers and the outer and inner wheels in contact with each other so as to provide interfaces between the spacers and the inner and outer wheels;
• electron beam welding along the interfaces between the spacers and the outer and inner wheels from a first side of the outer and inner wheels at an inlet side of a motive gas to the nozzle blades so that a weld depth of at most of half of a distance between the first side and the nozzle blades;
• and
• electron beam welding along the interfaces between the spacers and the outer and inner wheels from a second side opposite to the first side of the outer and inner wheels so that a weld depth is at least one third a height of the nozzle blades.