Following the client’s recent tube failures close to tube-to-header connections in their High Pressure High Temperature Superheater (HPHTSH) Outlet Header, ETD were invited to submit a proposal to carry out failure analysis of T91 tube samples removed from the failed area for a European Power Plant. The work involved performing tube failure analysis study based on laboratory testing and assessment of two removed tube samples.
The scope of the work carried out included:
- Visual and dimensional examination of the tube samples, including examination of the failure/damage location appearance and condition of internal and external tube surfaces and any deposits;
- Metallographic examination of the tube samples 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 materials;
- Chemical analysis of tube material to determine the chemical composition of the tube material to establish actual material constituents;
- Estimation of tube operating temperature based on measurements of steam-side oxide thickness, and evaluation of remaining creep life;
- Review of design drawings, 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.
This work was carried out to the satisfaction of the customer.
For more information about ETD’s Failure Analysis services, please click here.