Technology

Blasting

• Dry Blasting

  Dry blasting removes impurities such as scale and hard deposits formed on the rotor surface during operation by spraying aluminum oxide at high pressure together with compressed air.
  Major areas such as wheel dovetails are cleaned using glass beads.

• Wet(liquid abrasive) Blasting

  Wet blasting improves the surface friction of wheels to prevent slip between wheels, which may occur due to temperature gradients during operation.

Shot peening

Gas turbine rotors that have been operated for a certain period of time are vulnerable to damage caused by thermal fatigue or high-temperature thermal fatigue.
To prevent component damage, steel balls of a specified size are projected onto the rotor surface together with compressed air. This hardens the surface, improves fatigue strength, and introduces compressive residual stress on the rotor surface.

Rotor stacking & unstacking

When each stage of a damaged rotor needs to be disassembled, such as in disk-type rotors manufactured by GE or WH, the rotor, which consists of multiple wheels assembled with through bolts, is positioned vertically during unstacking and stacking work.
To ensure work efficiency, a hydraulic rotor stacking facility is installed around the rotor, allowing the work position to be adjusted freely as needed. This ensures both convenience and safety during maintenance work.

Turning, Grinding & Polishing

Turning, grinding, and polishing are performed for machining radial reference surfaces, rabbit fit dimensions, blade tenon sections and tips, journal surfaces, and thrust collar surfaces.
Turning using a cutting bite is applied for rough machining, grinding using a grinding stone is applied for finishing, and polishing using sandpaper and other materials is performed to achieve the required surface roughness.

Boring & Milling

Boring and milling are mainly performed for surface machining, hole machining, and inner and outer diameter machining of stationary components such as turbine diaphragms, journal bearings, and interstage seals.
Rough machining is performed using bites or cutters, while finishing is performed using grinding stones.

Balancing

During operation, rotating equipment may generate vibration due to centrifugal force caused by mass variation.
To minimize this vibration, balancing work is performed by measuring the amount of unbalance and phase angle, and then adding or removing the corresponding weight as needed.