Fabrication and formability evaluation of thick-wall chromized and coextruded superheater tubings for advanced cycle power applications

Abstract

Chromized and coextruded superheater tubings were welded and bent to construct the ultrasupercritical (USC) steam generator. Prior to the fabrication of the USC steam generator, welding and formability tests were performed to establish the fabrication procedures. In addition, mechanical and metallurgical investigations were also carried out. Welding of the chromized and coextruded tubings was satisfactorily accomplished and the joint showed sound structures and good strength properties, so that the established procedures were applied to the fabrication of the USC superheater. Bending formability for the chromized and coextruded thick wall tubings was evaluated, and the nocrackbending procedures for chromized tubing were developed.