Fracture Failure Mechanism Analysis of LP Second Stage Blades of a Gas Turbine

To systematically study the root cause of the fracture failure on a gas turbine LP(low pressure) second stage blade, the damage impression, fractography, material composition and metallurgical structure of the fractured section were studied. Vibration characteristic calcultaion analysis to the blade was performed under considering the working condition and structure characteristic. The analysis results revealed that the LP second stage Blade fracture is high cycled fracture (HCF), and mainly caused by furrowed manufacturing defects close to the fatigue source. Preventive measures were presented accordingly. The studied work is valuable for being a reference to fracture failure analysis and structure design for gas compressor blades.