Damage Mechanisms as per API
571
Training for Colleagues
Presented by: Mohammed Ashik Kp
General and Localized Corrosion
• Description:
• General corrosion is a uniform attack across
the surface of a material. Localized corrosion
includes pitting, crevice corrosion, and filiform
corrosion.
• Affected Materials:
• Most metals, including carbon steel, stainless
steel, and aluminum.
Galvanic Corrosion
• Description:
• Occurs when two dissimilar metals are
electrically connected in a corrosive
electrolyte, leading to accelerated corrosion of
the anodic metal.
• Affected Materials:
• Dissimilar metal pairs such as aluminum and
steel, copper and aluminum.
Erosion and Erosion-Corrosion
• Description:
• Erosion is the removal of material due to
mechanical action of fluid or solid particles.
Erosion-corrosion is the combined effect of
erosion and corrosion.
• Affected Materials:
• Carbon steel, stainless steel, and other alloys.
Cavitation
• Description:
• Cavitation occurs when vapor bubbles form
and collapse in a liquid, causing surface
damage.
• Affected Materials:
• Most metals, particularly in pumps and
propellers.
Fretting
• Description:
• Fretting occurs at contact areas subjected to
repeated small amplitude oscillatory motion,
leading to surface damage and wear.
• Affected Materials:
• Most metals, especially at bolted joints and
contact points.
High-Temperature Corrosion
• Description:
• Occurs due to the reaction of metals with hot
gases, typically at temperatures above 400°C.
• Affected Materials:
• Carbon steels, stainless steels, nickel alloys.
• Common Environments:
• Furnaces, boilers, gas turbines.
Sulfidation
• Description:
• Corrosion of materials by sulfur compounds,
particularly at high temperatures.
• Affected Materials:
• Carbon steel, stainless steels, low alloy steels.
• Common Environments:
• Petroleum refining, chemical processing.
Chloride Stress Corrosion Cracking
(Cl-SCC)
• Description:
• Cracking of austenitic stainless steels and
other alloys due to tensile stress and chloride
ions.
• Affected Materials:
• Austenitic stainless steels, nickel-based alloys.
• Common Environments:
Caustic Stress Corrosion Cracking
(Caustic Embrittlement)
• Description:
• Cracking of carbon steels and low alloy steels
due to tensile stress and caustic
environments.
• Affected Materials:
• Carbon steels, low alloy steels.
• Common Environments: