Steam Turbine Blade Manufacturing Process and Common Failures

Steam turbine blades are key executors of energy conversion, transforming the thermal and kinetic energy of high-temperature and high-pressure steam into mechanical energy, driving the rotor to rotate, and ultimately generating electrical energy through the generator.

Steam turbine blades, especially moving blades, have complex profiles and extremely high precision requirements. Their manufacture is a combination of advanced materials, precision machining, and special processes. They require a series of precision processes, including precision forging, five-axis CNC machining, rigorous heat treatment, and complex surface treatment, supplemented by comprehensive precision testing, to ultimately ensure their long-term safe and reliable operation under extreme conditions.
 

Steam turbine blades may experience some failures during long-term operation under harsh conditions:

• Water erosion: Commonly seen on the upper back arc of the last stage blades inlet edge, it needs to be strengthened by means such as laser cladding.

• Fatigue cracks: Often originate from stress concentration areas or caused by resonance. It is necessary to strictly control design and manufacturing quality to avoid resonance during operation.

• Fracture and detachment: This is the most serious accident, which may be caused by various factors such as foreign object impact, corrosion, resonance fatigue, and material defects.

• Scaling: Poor steam quality can lead to salt deposition on the blade surface, damaging aerodynamic performance and potentially causing vibration.