There are some types of corrosions which possible occur in steam boiler. Each type has reason for occurrence and location of occurrence. Base on them corrosion can be classified as pitting corrosion, fatigue corrosion, hydrogen embrittlement, caustic attack, acid attack, galvanic attack, inter granular, and stress corrosion. The following below is the description of corrosion based on location of occurrence in steam boiler area:
1. Pitting Corrosion
Pitting Corrosion usually occurs in economizer and tube which is not drained during maintenance.
2. Fatigue Corrosion
This type always causes cracking in location near welded area of water wall tubes.
3. Hydrogen Embrittlement
Hydrogen embrittlement generally occurs in water wall tubes
4. Caustic Attack
This corrosion often occurs in the grooving area under deposit on water wall tubes.
5. Acid Attack
Acid attack commonly occurs in water wall tubes area.
6. Galvanic Attack
Galvanic attack corrosion usually occurs in joint welding between two materials of tube both in superheater and reheater
7. Stress Corrosion
Stress corrosion commonly occurs in austenstic steel such as superheater tubes and reheater tubes.