Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

A braze repair process designed for SX/DS alloys in CFMI gas turbine engines

Some of the most critical components of gas turbine engines (widely used in aircraft and in other power generation applications) are turbine blades and nozzle guide vanes (NGV's). These components, made from highest quality Nickel super alloys, are very expensive. In recent years "Single Crystal" (or SX) and "Directionally Solidified" (or DS) versions of these materials have entered service. One of the most common forms of degradation of these materials in service is cracking due to thermal and mechanical fatigue. New part replacement can cost typically $5-10k per NGV. A satisfactory crack repair process (by brazing) would have the potential to extend the life of such components at about 20% of the cost of new part replacement.

One of the principal results of this project is a new braze repair process for single crystal (SX) and directionally solidified (DS) super alloy componets of gas turbine engines. SIFCO is the principal owner of this result. By a consortium agreement, the result is available to the other members of the SCARF Consortium, some of whom will exploit it in different market segments, or in different gas turbine engine applications.

Because of its strong market position in the repair of CFMI aero engine components, SIFCO will initially focus on the application of the result to this engine type. (This does not exclude the possibilities of other applications to other gas turbines).

After the completion of the SCARF project, once the properties of the SCARF braze repair system have been fully characterised, SIFCO will seek approvals from relevant approving bodies in the aviation sector. Becoming an approved repair centre for a specific repair process to a specific component of a CFMI gas turbine engine is a very important step in the exploitation of this kind of technology. The approving body can be either an Engine Manufacturer (e.g. the CFMI company) or an Aviation Authority (e.g. the FAA in the USA). Both of these bodies will require detailed test and characterisation data relating to the new braze process, and to the properties of the braze repaired component. That is why the detailed test and characterisation work carried out in the SCARF project is so important. It provides much of the data, which will be required by the "approvals" body.

When the necessary approvals have been obtained SIFCO will then be in a position to provide an improved repair service for its customers (operators and overhaulers of CFMI engines) who until now do not have an approved repair source for service damaged SX/DS components from CFM56 and related engines. The availability of a relatively cheap repair service for very expensive SX and DS turbine components, which have suffered crack damage during service, will confer major cost benefits to SIFCO's customers.

SIFCO grows its business by continuously increasing the range of approved turbine component repair services it can offer to its customer base.

Hence the exploitation of this result will occur seamlessly as part of SIFCO's ongoing business growth and development.

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