WELDING METHOD FOR TURBINE DIAPHRAGM

PURPOSE:To prevent the deformation of a product by providing racks corresponding to welding areas between a nozzle vane and partition plate and disposing respectively annular grooves and projections to the partition plate and inside and outside annular parts, then subjecting all the joint parts to electron beam welding. CONSTITUTION:The racks (h) to assure the molten metal are provided on a steam outlet side and inlet side to form a projecting shape to the outlet side and a recessed shape to the inlet side at the time of joining the end faces of the partition plate 1 and the nozzle vane 2. The formation of a recess on the molten surface of the partition plate is thereby prevented and the melting range is minimized, by which the welding deformation is extremely decreased. The annular groove 4 is provided to the partition plate 1 and the projections 4' are respectively disposed to the inside and outside rings 5, 6, then welding with an electron beam 7 is executed at the time of joining the partition plate 1 to the inside and outside rings 5, 6. All the joint parts are welded in a manner as to minimize the deformation by the above-mentioned method and therefore, the deformation of the product is prevented down to the min. extent.