Chloride-Induced Stress Corrosion Cracking (CISCC) of Strain-Hardened Type 304 Stainless Steel Bolts
Location: OFFSHORE : Floating Production Storage Unit
Incident Date: --- Time: ---
Type of Activity: Maintenance, inspection, testing
Type of Injury: ---
A number of strain-hardened, Type 304 stainless steel bolts, (ASTM A193 B8, Class 2) failed unexpectedly at an offshore facility during a pneumatic leak test of gas piping exiting a test separator. The bolts that failed were operating at temperatures below 50°C. The failure has been attributed to chloride-induced stress corrosion cracking (CISCC).
Strain-hardening austenitic stainless steel nuts and bolts to increase their strength may increase their sensitivity to CISCC and reduce their safe upper temperature limit. Other factors such as aggressive environments (e.g. offshore and coastal facilities and areas exposed to wet deluge testing) and increased stress / strain may also increase susceptibility to CISCC.
The intent of this Externally Shared Learning is to help mitigate the risk of such failures occurring elsewhere in new or existing facilities by highlighting the following, for consideration:
Corrective Actions and Recommendations:
What might you want to consider?
Safety Alert number: 297
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