Corrosion Mapping of Water Wall Tubes of Boiler using LFET

摘要

Corrosion of boiler tubes results in forced outage and it turns into huge loss of money. Maximum failure of water wall tubes is associated with the phenomenon of corrosion. The present paper discusses a technique for inspection of water walls before failure. Water wall tubes were inspected in situ condition by using Low Frequency Electromagnetic Technique (LEFT). Visual inspection of tubes was also carried out before scanning and it was observed that some of the tubes were bulged, eroded and having mechanical dent. During scanning signal wave forms were found not in uniform nature with respect to base line due to erosion, mechanical damage & bulging and those were recommended to be replaced.