In-situ Damage Assessment on Supporting Structure of Coal Conveyor

摘要

The supporting structure of conveyor in a coal power generation plant located in marine environment, was experiencing severe filiform corrosion. The structure has been used since 2009. This supporting structure holds the conveyor for coal transportation from the ship to the turbine. From visual inspection, it was clearly seen that around 80% of total area of the structure has been corroded, which influenced the strength of the structure. Hence damage evaluation of supporting structure was important to be carried out to determine the level of damage and to give the recommendation for repairment strategies. The damage evaluation method consisted of thickness measuring, chemical composition test, hardness test, microstructure analysis using replica technique and deposit analysis using SEM-EDS. The result showed that the type of material structure was AISI 1020. The highest reduction in measured thickness was 44%, which occurred dominantly on bottom and top flange of the structure. It was also found that in some joint areas, the material was perforated. The deposit analysis using SEM EDS found that the type of coating used on steel structure was not suitable for the marine environment.