Gas turbine blades and combustion chambers work under hard conditions, including high temperature and high stress. this working conditions bring different types of damage, such as foreign object damage, rubbing, high Strain low cycle Fatigue, high cycle fatigue, creep, oxidation, erosion, etc. these failure mechanisms cause several types of damages like coating removal, pits and cracks, micro-structure degeneration or creation of creep voids. hot section blades are among the most expensive parts in gas turbines. extending their lifetime is economical. this process is consisted of several steps:

 Recording
 Cleaning
 Visually inspection
 Dimensional control
 Coating striping
 NDT test
 Recording defect size and location
 Blending surface
 Welding or brazing
 Apply coating
 Visually inspect coating
 Controlling micro-structure and designing heat treatment cycle
 Heat treatment to restore the metallurgical and mechanical properties
 NDT test
 Checking micro-structure
 Dimensional control
 Perform final inspection