Creep and Fracture Behavior of Centrifugal Cast HP40Nb Alloy Containing Lead

Centrifugal cast HP40Nb alloys are commonly used as ethylene pyrolysis and reformer furnace tube materials. The actual wall temperature can usually reach 1423 K. The technical specifications require that the rupture life shall be at least 120 h under test condition of 1373 K at 17 MPa. The effects of amounts of Lead on the creep and stress rupture performance of the centrifugal cast HP40Nb alloy have been investigated at the temperature of 1373 K and the constant stress of 17 MPa. In this paper, HP40Nb alloy tubes with different contents of Lead element by centrifugal casting were selected, by high temperature stress rupture test and microscopic observation of creep damage, relationship between the content of Lead and high temperature stress rupture lives was given, as well as the threshold value of Lead element. It could provide the basis for ethylene pyrolysis furnace tubes manufacturers and design specifications.Copyright © 2012 by ASME