Corrosion Resistance of Next Generation Composite Tube Alloys for Recovery Boilers

Abstract Composite tubes made with either 304L, A825 or A625 exterior layers are commonly used to construct the lower-furnace waterwalls of black liquor recovery boilers currently operated in North America. While these composite tubes have been very successful in resisting sulphidation corrosion, they have experienced unanticipated problems with the exterior layer, namely cracking, and, to a lesser extent, preferential corrosion of port opening …