Vol. 54 No. 3 (2017)   Mitsubishi Hitachi Power Systems
Technical Papers

Development of 700°C Class Steam Turbine Technology

EIJI SAITO
SHIN NISHIMOTO
HIROYUKI ENDO
RYUICHI YAMAMOTO
KENJI KAWASAKI
JUN SATO

Mitsubishi Hitachi Power Systems, Ltd. (MHPS) has carried out the development of the 700°C class A-USC steam turbine through the auspices of a Japanese national project since 2008. We have developed a mainly Ni-based material with a high-temperature creep strength exceeding 100 MPa at 700°C for 100,000 hours with the successful production of a large-scale forged rotor weighing more than 10 tons, as well as fabrication technology for a dissimilar-material welded rotor using the Ni-based material and high Cr steel. We then conducted a full-scale, long-term rotational turbine test to verify these development technologies under test conditions where the steam turbine with a dissimilar-material welded rotor was utilized at a temperature higher than 700°C at 3600 rpm. This paper describes these development technologies.