Corrosion Resistance of Stainless Steel: Types, Causes, and Prevention
While stainless steel is known for its corrosion resistance, it is not immune to corrosion under certain conditions. Understanding corrosion types helps in proper material selection.
Types of Corrosion:
1. Pitting Corrosion: Localized attack that creates small pits or holes. Common in chloride environments. 316 and 317 grades with molybdenum offer better resistance.
2. Crevice Corrosion: Occurs in shielded areas where oxygen access is limited, such as under gaskets or deposits. Proper design and grade selection are essential.
3. Stress Corrosion Cracking (SCC): Cracking caused by combined tensile stress and corrosive environment. Chlorides are a common cause. Duplex grades offer superior SCC resistance.
4. Intergranular Corrosion: Attack along grain boundaries, often due to sensitization from welding. Low-carbon (L) grades and stabilized grades prevent this.
5. Galvanic Corrosion: Occurs when dissimilar metals are in electrical contact in a corrosive environment.
Prevention Strategies:
- Select the appropriate grade for the environment
- Maintain passive surface condition
- Avoid contamination with carbon steel
- Proper design to avoid crevices
- Control environmental parameters
Our Expertise:
Yuze Metal's technical team can assist with material selection for challenging corrosion environments.