| 摘要 |
1467163 Stator blade fixing HITACHI Ltd 18 June 1974 [18 June 1973] 27002/74 Heading F1T [Also in Division B3] In joining together a member of metal A to a member of a dissimilar metal, B (DWB3), filler metal is weld deposited on the metal A member, a free surface of said filler metal is machined to provide a joint surface, and the metal B member is electron beam welded to the filler metal at said machined surface, the filler metal being substantially of the metal B such that the electron beam produced weld is not deflected from the weld interface. As shown, a steam turbine stationary diaphragm comprises blades 1 joined to inner and outer rings 4, 5 by way of intermediate rings 10. The rims and rings 4, 5, 10 are of low alloy heat resisting steel and the blades 1 are of 13% Cr stainless steel. The rings 10 have circumferential recesses and apertures entering into the bottom of the recesses. First, the blades 1 are inserted into the apertures and fillet welded to the rings 10 by filler metal applied at 11. Then further filler metal substantially of the same metal as that of the rims, is applied in the recesses to provide build-up portions 12 which are then machined with the rings so that the outer circumferential surfaces of the rings 10 and build-up portions are flush and that recesses remain into which projections 4A, 5A of the rims 4, 5 are fitted. Finally, electron beam welding at 13 welds the rings 10 and build-up portion 12 to the rims 4, 5. Further example rim metals are 2À25% Cr, 1% Mo, 1% Cr, 0À5% Mo; 0À5% Mo; and carbon steel, and a difference in Cr and Mo content of less than 0À25% and 0À20% respectively between the rim metal and the metals electron beam welded thereto is allowable. In a prior art example, Fig. 2, (not shown), following manual arc welding of the blades to the intermediate rings, submerged arc build-up welding is effected to fill lateral grooves between the inner and outer rims and the rings. |
