Laser robots cut costs

A new laser welding technique is repairing power station turbine rotor blades in minutes. Called In Situ Laser Surfacing, the development is the product of a collective effort by several research institutions and power station operators.

As the name implies, In Situ Laser Surfacing allows flaws from wet steam erosion on the blades of low-pressure steam turbines to be repaired in place – without the need for the turbine to be dismantled and the blades removed.

Some power station operators have reported that current blade repair, or replacement, costs $250,000 per turbine per day in downtime – or up to $2.5 million in total per turbine. A typical low-pressure steam turbine rotor has 180 last-row blades, each about a metre long, with a replacement cost of $10,000 each if they cannot be repaired to the level of their original aerodynamic precision.

CSIRO’s Dr. Nazmul Alam explains that the new method uses high-power laser energy to fuse a metal alloy powder to the turbine blade’s surface.