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What is stress relaxation cracking?

Stress relaxation cracking (SRC) is a phenomenon where a material experiences cracking due to the gradual decrease in internal stress over time, often at elevated temperatures. Unlike stress corrosion cracking, which requires both stress and a corrosive environment, SRC primarily occurs due to the relaxation of residual or applied stresses in a high-temperature environment. Key factors contributing to SRC include:

  1. Elevated Temperatures: Typically occurs at high temperatures where materials are more susceptible to creep and stress relaxation.
  2. Internal Stresses: Residual stresses from manufacturing processes or applied stresses during service gradually decrease over time.
  3. Material Susceptibility: Certain alloys and materials are more prone to SRC, especially those used in high-temperature applications like turbine blades and pressure vessels.

SRC is characterized by the formation of cracks that can lead to material failure. It is a significant concern in industries such as power generation, petrochemical, and aerospace, where components operate under high stress and temperature conditions.