Key factors influencing Corrosion fatigue of stainless steel pipe

It is important to consider these factors during the design, installation, and maintenance of stainless steel pipes to mitigate the risk of corrosion fatigue and ensure their long-term performance.

  1. Corrosive environment: The presence of corrosive substances such as chlorides, sulfides, acids, or alkaline solutions can accelerate the corrosion process and promote corrosion fatigue.
  2. Stress levels: High cyclic stresses or stress concentrations can initiate and propagate cracks in stainless steel pipes, leading to corrosion fatigue failure.
  3. Frequency and magnitude of cyclic loading: Frequent or high-amplitude cyclic loading can increase the susceptibility of stainless steel pipes to corrosion fatigue.
  4. Material properties: The composition, microstructure, and mechanical properties of the stainless steel used in the pipe construction play a significant role in its resistance to corrosion fatigue.
  5. Surface condition: Surface defects, roughness, or contaminants on the pipe’s surface can act as stress concentration sites and accelerate corrosion fatigue.
  6. Temperature: Elevated temperatures can enhance the corrosion rate and reduce the fatigue strength of stainless steel pipes, increasing the likelihood of corrosion fatigue failure.
  7. Design and fabrication: Poor design or manufacturing practices, including inadequate material selection, improper welding, or insufficient corrosion protection measures, can contribute to corrosion fatigue.
Stainless steel pipes, brushed metal on white background.
Stainless steel pipes, brushed metal on white background.

Local corrosion of stainless steel pipes caused by the combined action of alternating stress and medium. There are many explanations about the cause of Corrosion fatigue caused by the combined action of mechanics (dynamic stress) and electrochemistry (corrosive medium), but no consistent conclusion has been reached at present. In terms of its generation mechanism, a pitting stress concentration model was proposed; Model of preferential dissolution of transformed metals; Metal film rupture model and active substance adsorption model. However, under the action of alternating stress, the rupture of passive film, the dissolution of sliding steps and the repeated action of re passivation under the combined action of medium and alternating stress are the key factors that can affect the Corrosion fatigue process of stainless steel tubes.
Prevent and reduce the alternating stress borne by stainless steel seamless pipe equipment and components, including eliminating stress concentration on the structure and surface defects of stainless steel seamless pipes; Choose stainless steel seamless pipes with high fatigue strength, excellent corrosion resistance, and fine grains, while duplex stainless steel seamless pipes are a preferred material for selection.

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