Advanced TIG and Nd-YAG repair of blades and vanes

Kawasaki JS6 6-axis robot and a 3-axis gantry at TWI

The high cost of replacing damaged blades and nozzle guide vanes (NGVs) in the high pressure (HP) section of gas turbines has led to end-user interest in the use of repaired components. Most HP blades and NGVs are made from nickel superalloys, which have superior creep and strength properties at elevated temperature, but are considered extremely difficult to repair by conventional processes, such as TIG welding and brazing, because of their susceptibility to HAZ and weld metal cracking. The problem is compounded by the increasing use of directionally solidified and single crystal alloys, where creep properties are undermined by the grain growth encouraged by fusion repair processes.

TWI offers expertise in the weld repair of gas turbine blades and vanes by TIG and Nd:YAG laser welding. Examples of current programmes, including a Group Sponsored Project at TWI include:

Advanced repair of hot section gas turbine components
Production of high strength repairs to IN738LC components with matching consumable
Production of high strength repairs to single crystal alloy components (CMSX4)
Determination of limits to blade repair (e.g. maximum crack depth)
Validation of novel repair procedures
Validation of high strength repairs in structural locations
Automation of turbine blade repair procedures

For further information, please contact: power@twi.co.uk