Examination of a failed roof tube from a bagasse boiler showed transverse through-cracks and extensive pitting. The pitting was typically oxygen induced pitting and numerous fatigue cracks had started within these pits. It is highly probable that the pitting occurred during an idle period (a drought) due to oxygen ingress and failure to maintain a sufficient excess of the oxygen scavenger, sodium sulphite. The transverse orientation of the cracks and other factors suggest that the fatigue cracking is related to tube vibrations.
Reference:
Heyes, AM. 2001. Oxygen pitting failure of a bagasse boiler tube. Engineering failure analysis, vol 8(2), pp 123-131
Heyes, A. (2001). Oxygen pitting failure of a bagasse boiler tube. http://hdl.handle.net/10204/1595
Heyes, AM "Oxygen pitting failure of a bagasse boiler tube." (2001) http://hdl.handle.net/10204/1595
Heyes A. Oxygen pitting failure of a bagasse boiler tube. 2001; http://hdl.handle.net/10204/1595.
