📌 Rail Transit Heat Exchanger Tube - Stress corrosion cracking in fertilizer dust

Industry: Rail Transit · Severity: Critical · Mechanism: Stress corrosion cracking · Risk: 93/100

🧾 Summary

A heat exchanger tube used in a rail transit application shows stress corrosion cracking risk after exposure to fertilizer dust. The design review focuses on material pairing, geometry, coating coverage, inspection access, and realistic validation testing.

⚠️ Design Risk

Likely weak points include local electrolyte retention, incompatible material pairing, coating discontinuities, trapped debris, and missing acceptance criteria for corrosion validation.

🛠️ Recommended Controls

Recommended controls: cyclic corrosion validation, edge-radius update, and inspection hold point. Add drawing notes, supplier evidence requirements, and a validation plan that reflects the expected service environment.

🎓 Learning Notes

Learners should identify the corrosion mechanism, estimate severity, and decide whether prevention should come from material change, coating change, geometry change, sealing, isolation, or inspection planning.