Abstract
Compressor rotor blades in marine engineering applications are exposed to harsh, corrosive environments and complex aerodynamic loads, making them prone to premature failure. This study investigates the fracture of 12th-stage 2Cr13 martensitic stainless-steel blades following a maintenance overhaul. Despite the replacement of several cracked blades, five blades fractured shortly after restart, accompanied by abnormal vibration. A comprehensive failure analysis was conducted, including macroscopic inspection, fractographic observation, energy-dispersive spectroscopy, metallographic examination, and mechanical property testing. The results indicate that the fractures are multi-source high-cycle fatigue. Crack initiation in the new blade originated from pre-existing transverse mechanical damage, while in the old blades, it initiated from sharp pits and microcracks introduced by sandblasting, which compromised surface integrity. The material exhibited a normal tempered sorbite structure and adequate mechanical properties, with slight strengthening due to service-induced precipitation and dislocation accumulation. The failure followed a typical evolution of multi-source initiation, propagation, crack coalescence, and final overload ductile fracture. These findings highlight the critical role of surface integrity in blade reliability.