Repairing Gas Turbine Hot Section Airfoils Today

The team approach to development and application of repair techniques for gas turbine hot section airfoils can be effective in achieving goals of product safety, conservation of critical materials, thermal protection and operational cost control. This concept is explored and various repair techniques and processes are described as well as is their interrelation. Included is the application of hot-isostatic-pressing, diffusion joining, controlled chamber tungsten inert gas welding, electrical discharge machining, laser drilling, electro-chemical machining, abrasive flow machining, airfoil replacement and blade tip sulfidation repair. Protective coatings considered are low pressure plasma spray, physical vapor deposition, platinum aluminide pack coating and overcoating. An example of cost effectiveness is presented.

Repair engineering can extend useful life of hot section airfoils without compromising safety, critical materials and cost considerations.