Oxygen corrosion is an electrochemical process in which the metal dissolves at the anode and releases electrons which are subsequently consumed by oxygen thereby resulting in distinctive corrosion pits.
Oxygen Corrosion | Materials And Corrosion Control
| Damage Mechanism | Oxygen Corrosion |
Damage Description |
· Oxygen corrosion is an electrochemical process in which the metal dissolves at the anode and releases electrons which are subsequently consumed by oxygen thereby resulting in distinctive corrosion pits.
· Oxygen pits can rapidly penetrate through metal surfaces leading to metal failure. |
Affected Materials |
· Most common materials of construction: carbon steel, 300 & 400 stainless steel, Aluminum, copper, and some nickel base alloys. |
Control Methodology |
· Oxygen control is generally both mechanical and chemical process through deaeration and chemical scavengers respectively.
· Treat systems containing oxygen with the proper application of oxygen scavengers. · Maintain the dissolved oxygen content in the water phase below the minimum levels, 20 ppb as per SAES-L-133. · Keep closed operating systems out of oxygen ingress. · Treat hydrotest water of new, revalidated, and refurbished equipment with oxygen scavenger when the equipment contact time with hydrotest water may exceed 14 days as per |
Monitoring Techniques |
· Establish oxygen monitoring program to be taken in a regular basis
· Install coupons and online oxygen analyzers for evidence of oxygen corrosion failure. |
Inspection Frequency |
· Regular UT, coupons, probes, OSI TMLs for piping, and visual inspection at T&I |
KPIs |
· Monitor dissolved oxygen content in water to be below 20 ppb. · Monitor the treating oxygen scavenger residual to be above |
Reference Resources (Standards/GIs/BPs) |
· SAES-L-133
· SAES-A-007 |
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