CORROSION TYPE OF FAILURE ( (Types of corrosion (galvanic corrosion image…
CORROSION TYPE OF FAILURE
Corrosion in metals
Electrochemical phenomenon caused by environmental or external factors that react with metals generating losses in their properties.
Use of stainless metals
• Stainless steel
Use of external protections
• Galvanized: process where a metal is coated with zinc to protect the material.
• Special paints: process where the material is coated with layers of a non-corrosive viscous fluid.
• Anodization: Electrolytic process where a somewhat inert film is formed on the surface of a metallic element.
It's refers to the localized attack on a metal surface at, or immediately adjacent to, the gap or crevice between two joining surfaces. Mainly due to differences i the amounts of available oxygen
How to prevent crevice service corrosion
Use welded butt joints instead of riveted or bolted joints in new equipment
Eliminate crevice in existing lap joints by continuous welding or soldering
Avoid creatin stagnant conditions and ensure complete drainage in vessels
Use higher alloys for increased resistance to crevice corrosion
It's an electrochemical process in which a metal corrodes by being in direct contact with another metal (more noble), and both metals are submerged in an electrolyte or humid environment
This principle is applied in ships to prevent corrosion on the shell
Types of corrosion
Dealloying, Selective Leaching & Graphitic Corrosion
Stress-corrosion cracking (SCC)
Types to failures for corrosion