Atsuro Iseda

Long-Term Service Experience With Advanced Austenitic Alloys in Eddystone Power Station

A service exposure test of advanced austenitic alloys was performed at Eddystone Power Station Unit 1. The alloys tested were TP347HFG, SUPER304H and HR3C as well as 17-14CuMo as a reference material. They were installed in the final super-heater section in 1991 and were removed in 2004. The service exposure duration is 75,075 h with the steam temperature and pressure estimated 615 °C and 35 MPa, respectively. Post exposure examination has proved no marked hot-corrosion and steam oxidation have occurred for the TP347HFG, SUPER304H and HR3C specimens, while severe hot-corrosion and exfoliation of steam-oxide films was pronounced in 17-14CuMo specimens. It is also found that HR3C exhibits the highest tensile strength with a lowest ductility and TP347HFG does vice versa, while the strength of SUPER304H is equivalent to that of 17-14CuMo with much better ductility. Short-term creep rupture strengths of these alloys have been reduced to some extent after the long-term service exposure and a longer-term creep rupture testing has been in progress. Microstructural evolution of the TP347HFG, SUPER304H and HR3C as well as 17-14CuMo during the long-term service exposure have been analyzed using a detailed TEM examination and the chemical analysis of extraction residue of the exposed specimens.Copyright

Development of 12Cr-1Mo-1W-V-Nb Steel for Elevated Temperature Applications

The 12Cr steels have attracted attention for high temperature application due to their resistance to corrosive environments and good elevated temperature strength.

Service Experiences of 12Cr-1Mo-1W-V-Nb Steel and 9Cr-2Mo Steel in a Power Boiler

Both newly developed duplex structure low C-12Cr-1Mo-1W-V-Nb steel (HCM12)[1] and low C-9Cr-2Mo steel (HCM9M)[2] have a practical capability to be used for steam generator tubing from the aspect of oxidation resistance and elevated temperature strength as well as weldability and formability.