The Selection of Materials and Fabricating Techniques for the Eddystone Boiler and Sulzer Control Valves

The Eddystone supercritical boiler, designed to operate at a maximum pressure of 5000 psig and 1200-F temperature, required the use of new high-temperature materials in tubes and stop valves in order to avoid excessive wall thicknesses. None of the materials approved by the ASME Boiler and Pressure Vessel Code for superheater service had the required properties. The present paper describes the high-temperature tests carried out and the welding development which led to the selection of the new materials. The properties of these new materials are discussed. Design features and fabricating procedures for the tubes and valves are presented.