GE94-02: Repair Flow Testing and Calibration Procedures for ...

The strengths and weakness of each system were evaluated in terms of the errors in indicated
temperature that could result. This evaluation included the analysis of the optic properties of
pieces of TBC that had been in service for widely different amounts of time. The provision of
guidance to users considering the acquisition of an optical pyrometry system for monitoring the
surface temperature of first stage blades with TBC is also included.
GEN99‐22. Analysis of Compressor Water Washing. May 2000.
This report provides set guidelines about the utilization of compressor water washing for
industrial gas turbines. A thorough investigation of the benefits and adverse effects of both off‐
line and on‐line water washing are analyzed with specific recommendations provided to
operators of gas turbines. Extensive surveys were performed to gather the relevant industry
data from gas turbine operators, vendors and OEMs. An economic analysis of the value of
compressor water washing is also included as a guideline to operators when making economic
decisions regarding water washing.
GEN99‐24. Status of Repair Technology Available for IN‐738 Gas Turbine Blade
(Bucket) Repair. March 2000.
The current worldwide population of heavy frame gas turbines used for electric power
generation utilizes the superalloy IN 738LC more than any other material for the critical rotating
blades in the hottest turbine stages. Significant damage that is routinely incurred during service
has historically resulted in blade replacement rather than repair because the material is
extremely difficult to weld without cracking. Traditional arc welding processes have been
developed, but they can only be implemented when weld filler alloys much weaker than the
blade alloy are employed. Thus, repairs have been limited to the outermost extremities of the
blades where the applied stress is very low. Replacement costs, which have always been high,
have increased dramatically in recent years and this has spawned development programs at
many of the companies engaged in commercial blade repair. Little, however, is known about
the actual progress made.
The CTC 2 organization initiated this project to determine the maximum blade repair limits that
are currently being implemented in the industry and to gauge the status of development work.
The ultimate goal was to find if current repair limits could be increased. A formal survey was
distributed to a worldwide list of repair companies. The results of that survey form the basis of
this report.