1986 年 4 巻 4 号 p. 703-709
Characteristics of creep rupture strength and brittleness under steam turbine operation for 2%Cr-1Mo steel plate EB welded joint have been investigated besides that of high temperature strength and stress relief cracking reported already. As the result, high-intermediate pressure outer casing of 380MW steam turbine have been manufactured by welded structure of 21/4Cr-lMo steel plate in stead of Cr-Mo-V cast steel previously used.
Results are summarized as follows;
(1) 105 Hr creep rutpure strength of EB welded joint satisfys with scatter band of base metal and allowable stress indicated by Table UCS23 of ASME SEC. VIII.
(2) FATT of HAZ and weld metal for EB welded joint increase with holding time at 538°C. But it's value saturates more than about 8000 Hr and is lower than that of Cr-Mo-V cast steel.
(3) EB welding have been applied to steel plate welded structure of high-intermediate pressure outer casing for output power 380MW steam turbine. It's maximum thickness EB welded was 110 mm.