Laser Cladding of Turbine Blades

LASER CLADDING OF TURBINE BLADES

• Turbine blades are high value critical components which are used both in aerospace as well as land based IGT(industrial gas turbine) components.
• These blades are subjected to a very harsh working environment of high temperatures, high mechanical loads and they are continuously undergoing corrosion and erosion due to fuel and air contaminants .Over a period of time there is significant erosion at the leading edges and contours of these turbine blades.
• Replacing these turbines is expensive, and also, during the time required to replace turbines, the working of the system is stopped, so, the best way is to increase the service life of the turbine blades with surface treatment methods like cladding and hardening.

Advantages of Using Laser Cladding

There are various conventional cladding/welding technologies available for repair of turbine blades like PTA , GTAW etc. The problem with these conventional methods is the high heat input, which causes deformation of the components.

In Laser cladding , a laser beam of appropriate spot size is used to melt a cladding powder directly on the part  creating a metallurgical bond

• Due to low and precisely controlled heat input there is very less chance of deformation in the blade while cladding is being done.
• Since the cooling rates are higher, high hardness can be achieved in the cladding layer which inturn increases the life cycle of the part.
• Laser cladding gives the flexibility of using various metal powder combinations depending on the base material of turbine.
• Many novel Nickel and Cobalt based super alloys can be easily cladded on the damaged turbine which are sometimes not possible with conventional welding/overlay techniques.
• In process like TIG ,  overhang upto few mm is created on the sides of the blade while rebuilding , so more material is deposited and then removed whereas  In laser cladding near  net-shape rebuild can be done.
• In comparison to TIG/PTA , laser cladding results in pore and crack free cladding.

In Summary, Laser cladding technology provides a very efficient , robust and repeatable solution for repair of worn out turbine blades, resulting in faster turnaround time and reduced down time at the customer end at a fraction of cost of the original blades.

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