Final Superheater Outlet Header and Live Steam Piping

Final Superheater Outlet Header and Live Steam Piping 

Due to the considerably increased wall thicknesses, the martensites lose their advantage over the austenites in terms of the allowable rate of temperature change. At 600 °C, this rate amounts for P91 only half the value for the austenite. Therefore, the 

For economic reasons, in the development of new materials for next-generation power plants since 2000, a fundamental requirement comprised the application of nonaustenitic materials for the live steam piping. To protect at the same time the thick-walled weld between the live steam piping and the final SH outlet header against overstress due to differential thermal expansion of the materials used, the SH outlet header had to be manufactured also from martensitic materials 11]. The SH outlet header is equipped with martensitic connecting tubes so that the weld between the austenitic SH heating surfaces and the martensitic SH outlet headers is done via these tubes and therefore with comparatively small welds that show less problems due to differential thermal expansions of the applied materials. 

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