ETD is pleased to announce the successful recent completion of a root cause failure analysis project for a North American based plant.
The plant was experiencing a failure of the IP Economiser outlet header tube. During the HRSG inspection, a pin hole leak was observed on the stub tube of IP Econ OH and the plant decided to replace the portion. The pin hole leak was found 6mm away from header-tube weldment (fillet weld). After the incident, the client completed extensive inspection on the header and dye penetrant test and no abnormalities were found. Therefore, ETD was invited to submit a proposal to carry out failure analysis of this IP econ tube sample removed from the failed area. The work involved performing tube failure analysis study based on laboratory testing and assessment of one removed tube sample.
The objectives and scope of the work to be carried out for one tube sample was:
Visual and dimensional examination of the tube sample, including examination of the failure/damage location appearance and condition of internal and external tube surfaces and any deposits;
Metallographic examination of the tube sample to assess the condition of the microstructure and to identify the damage/failure mechanism(s);
Hardness testing and evaluation to determine the equivalent tensile strength values (using published hardness/UTS correlation tables) to assess the mechanical strength or softening of the tube material;
Chemical analysis of base material to determine the chemical composition of the tube material to establish actual material constituents;
Chemical analysis of internal oxide/ deposits to determine the presence of impurities and constituents that may lead to the failure (depending on the oxide thickness);
Estimation of tube operating temperature based on measurements of steam-side oxide thickness, and evaluation of remaining creep life;
Review of design drawings, tube arrangement, operating parameters, previous failure and maintenance history;
Root Cause Failure Analysis (RCA) based on the findings of above investigations;
Report covering results of investigations, failure analysis & recommendations for remedial actions to prevent repeat tube failures.
ETD has established expertise in the failure analysis. For more information about our failure analysis services please click here.