DEGREASE AND PASSIVATION
PROCEDURE
Klaikangwol A.
URICH ENGINEERING PLUS CO.,LTD. T.083-4966808
Degrease and Passivation Procedure
1. Scope
This procedure outlines the steps for degreasing and
passivating stainless steel and other corrosion-resistant
metal parts to remove contaminants and enhance corrosion
resistance.
2. Safety Precautions
• Wear appropriate PPE: gloves, safety goggles, face shield,
apron.
• Ensure proper ventilation.
• Refer to the Material Safety Data Sheets (MSDS) for all
chemicals used.
3. Equipment and Materials
• Alkaline or solvent-based degreaser
• Clean water (DI or RO preferred)
• Acidic passivation solution (e.g., nitric acid, citric acid)
• Plastic or stainless steel tanks (avoid carbon steel)
• Non-metallic brushes or soft cloths
• pH test strips or meter
• Optional: ultrasonic cleaner
4. Degreasing Process
4.1 Initial Cleaning
• Remove visible debris using a brush or cloth.
หน้า 1|3
• If applicable, disassemble parts for better access to
surfaces.
4.2 Degreasing
• Immerse or spray the parts with a degreasing solution
(alkaline or solvent-based).
• Use ultrasonic agitation or manual brushing if required.
• Dwell time: 10–30 minutes depending on contamination
level.
4.3 Rinse
• Thoroughly rinse parts with clean water to remove
degreaser residues.
• Check for water break (uniform sheeting indicates clean
surface).
5. Passivation Process
5.1 Solution Preparation
• Use a citric acid (4–10%) or nitric acid (20–50%) solution.
• Heat solution to 40–60°C (104–140°F) if recommended.
• Ensure pH is within acceptable range (varies by solution
type).
หน้า 2|3
5.2 Passivation
• Immerse parts fully in the passivation solution.
• Dwell time:
- Citric acid: 20–30 minutes
- Nitric acid: 20–60 minutes
5.3 Rinse
• Rinse thoroughly with clean water.
• For critical applications, use DI/RO water to prevent
spotting.
5.4 Final Rinse and Dry
• Optional: final rinse in a separate DI water tank.
• Dry parts using clean, oil-free air or drying cabinet.
6. Inspection and Documentation
• Visually inspect for surface cleanliness and uniformity.
• Optional: perform water break test or passivation
verification test (per ASTM A967).
• Record batch number, solution used, time, and operator
initials.
7. Disposal
• Dispose of used chemicals according to local
environmental and safety regulations.
• Neutralize acidic/alkaline waste before disposal if
required.
หน้า 3|3