Abstract
This paper reports the properties of nickel based alloy 617B and 740H used for superheater header for 700℃ USC boilers. The strength of the superheater header made of P91, P92, P122, VM 12 SHC, 9Cr-3w-3Co, HR6W, 617B and 740H piping with different diameters under different temperatures are calculated according to ASME Boiler and Pressure Vessel Code. This paper also analyses the suitable service temperature range of 700℃ superheater header manufactured by P91, P92, P122, VM 12 SHC, 9Cr-3w-3Co, HR6W, 617B and 740H piping, and puts forward some suggestions on 700℃ superheater header material selection. In the condition that the header metal design temperature is higher than 630℃, 617B should be selected to manufacture the header as the thickness less than 80mm, and 740H should be selected to manufacture the header as the thickness more than 80mm.
