{"id":20894,"date":"2025-11-27T01:30:47","date_gmt":"2025-11-27T07:30:47","guid":{"rendered":"https:\/\/entrustsol.com\/?p=20894"},"modified":"2025-05-12T12:55:57","modified_gmt":"2025-05-12T17:55:57","slug":"guidelines-to-achieve-successful-gas-turbine-part-refurbishment","status":"publish","type":"post","link":"https:\/\/entrustsol.com\/guidelines-to-achieve-successful-gas-turbine-part-refurbishment\/","title":{"rendered":"Guidelines to Achieve Successful Gas Turbine Part Refurbishment"},"content":{"rendered":"

\"\"<\/p>\n

By Tom Reid, Vice President of Power Generation Services, ENTRUST Solutions Group<\/i><\/p>\n

Gas turbine hot-section hardware requires regular refurbishment after a specified number of operating hours, stop-start cycles or a combination of the two. These repairs are critical to maintaining optimal performance and extending the life of the equipment. However, the repair processes present significant challenges due to the variability in part conditions, process complexities and the human element.\u00a0<\/span><\/p>\n

To ensure success, careful attention and expertise must be applied to every stage of refurbishment.<\/span><\/p>\n

Key Gas Turbine Repair Processes<\/span><\/h2>\n
    \n
  1. Inspection<\/span><\/li>\n
  2. Coating Removal<\/span><\/li>\n
  3. Joining<\/span><\/li>\n
  4. Machining<\/span><\/li>\n
  5. Coating Application<\/span><\/li>\n<\/ol>\n

    Common Failure Mechanisms<\/span><\/h2>\n

    Key failure mechanisms for hot-section hardware include oxidation, creep, cracking and dimensional distortion. It is vital to conduct robust incoming inspections to accurately define the repair scope and identify unrepairable hardware from the outset.<\/span><\/p>\n

    Coating Removal<\/span><\/h2>\n

    After a service interval, coatings are typically depleted or spalled. Ceramic coatings are removed through abrasive grit blasting, while metallic bond coats are removed via acid stripping.\u00a0<\/span><\/p>\n

    Common issues include excessive base metal removal, inter-granular acid attack and incomplete coating removal. These challenges require precision to mitigate potential damage.<\/span><\/p>\n

    Repairing Cracking<\/span><\/h2>\n

    Cracking from thermal-mechanical fatigue is often present and can be particularly challenging to repair, especially with the increased use of nickel-based superalloys. Welding and brazing are the most common processes for addressing cracks.\u00a0<\/span><\/p>\n

    Factors such as material selection, surface preparation and pre- and post-process heat treatment significantly impact the quality of repair.<\/span><\/p>\n

    Machining and Dimensional Restoration<\/span><\/h2>\n

    Material build-up and machining are often necessary during refurbishment. Processes such as tip repair or hard face restoration must address part creep and distortion, which complicate achieving desired dimensional results.\u00a0<\/span><\/p>\n

    Reliable fixturing and adaptable machining techniques are critical to maintaining precision despite the variability in part condition.<\/span><\/p>\n

    Coating Reapplication<\/span><\/h2>\n

    Thermal spray processes are frequently used to apply new coating systems to hardware. Recoating existing components, especially those with features like cooling holes and seal slots, is more complex than coating newly manufactured parts.\u00a0<\/span><\/p>\n

    Factors affecting coating quality include part geometry, pre-heat temperature, surface preparation, gas and powder properties and coating gun condition.<\/span><\/p>\n

    Recommended Guidelines to Enhance Repair Quality<\/span><\/h2>\n

    1. Get Engaged Early in the Process<\/span><\/h3>\n