Recommendations for Assessing Susceptibility to CLSCC
The susceptibility to Chloride stress corrosion cracking CLSCC is usually assessed on the basis of chloride content, pH and temperature. In our view there are additional factors that should be taken into account when assessing the susceptibility with both new and existing pipework or vessels that have accumulated significant service.
These include:
• Operation involves high temperature excursions. Susceptibility should be determined by the highest temperature reached during any part of duty or maintenance operations, irrespective of the duration of the excursion.
• Liquid can dry out allowing chlorides to concentrate or form chloride-rich solid films.
• Pitting and/or crevice corrosion already exist.
• The steel was manufactured before 1970 with possible higher levels of impurities.
• Possibility of sensitisation.
• Free machining grades.
• Surface finish has deteriorated since manufacture.
• Iron contamination of surfaces.
• Welding during manufacture, modification and repair.
• Design or manufacturing details where chlorides can accumulate, e.g. roots of partial penetration welds.
• Operation causes stress cycles.
It is recommended that susceptibility to CLSCC Chloride Stress Corrosion Cracking is assessed by extending the API 581 approach to take account of these factors. A flow diagram for the proposed extension of the API 581 method, and crack growth rates are suggested for susceptibility categories.
Related References:
1. austenitic stainless steel
2. Stress Corrosion Cracking SCC
3. Chloride Stress Corrosion Cracking (CLSCC)
4. Stress Corrosin Cracking SCC of Duplex Stainless Steel
5. Chloride Stress Corrosion Cracking in Austenitic Stainless Steel
6. Recommendations for Assessing Susceptibility to CLSCC
7. Main Findings on CLSCC in the Reactors
8. Literature Review to Chloride Stress Corrosion Cracking
9. CLSCC Chloride Stress Corrosion Cracking Mechanism
10. Factors Affecting CLSCC Chloride Stress Corrosion Cracking
11. Controlling Chloride Stress Corrosion Cracking
12. Structural Integrity Assessment
13. Non-Destructive Examination NDE
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