LOCALIZED SWELLING OF FE-CR-NI ALLOY ROLLERS IN HIGH-TEMPERATURE APPLICATIONS

Localized swelling has been observed in 24Cr-24Ni-Na steel transportat ion rollers used in the normalizing furnace of a plate mill after prol onged service at high temperature, Due to high localized thermal and m echanical stresses, the chromia layer formed on the roller surface rup tures, exposing the roller substrate to furnace oxygen, Oxidation af s econd-phase carbides results in the formation af carbon monoxide at ve ry high partial pressure, This leads to formation of voids, leading in turn to localized swelling of the roller material.