Chloride stress corrosion cracking (Cl-SCC) is known to occur in austenitic stainless steels operating at temperatures above 60 °C (150 °F). This paper, however, will discuss external Cl-SCC failures that occurred at ambient conditions. These failures occurred in stainless steel grade 304 bolts used as valve bonnet stud bolts. The failure caused total disengagement of the valve bonnet. These valves were located approximately 1 km from the seashore. In addition, the valves were located underneath a seawater deluge system used for fire protection which was periodically tested resulting in the valves being wetted by seawater. This paper provides details related to the materials, environmental conditions and mechanical properties of these bolts and provides recommendations to avoid such failures in the future.

Subject
Scanning electron microscopy, Test methods, Energy dispersive X-ray spectroscopy, Corrosion failures, Marine environments, Materials, Valves, Transgranular stress corrosion cracking, Seawater, Failure analysis, Stainless steel, Chlorides, Chloride stress corrosion cracking
Keywords:
Chloride stress corrosion cracking, Cl-SCC, external, austenitic stainless steel, 304, UNS S30400, bolt, stud, A193 B8
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2024
Association for Materials Protection and Performance (AMPP)
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