Stainless Steel Passivation
Restore Corrosion Resistance with Controlled Passivation
Fukar provides passivation services to remove free iron contamination and support the restoration of the chromium-rich passive layer on stainless steel components.
The process helps reduce rust staining risk after machining, fabrication, and handling, and supports corrosion-critical applications.
Key Benefits
Why Use Passivation
Removes Free Iron
Eliminates surface contamination introduced during manufacturing.
Improves Corrosion Behavior
Supports stable stainless performance in demanding environments.
Specification Compliance
Can be aligned with customer quality requirements and standards.
Process Overview
What is Stainless Steel Passivation?
Stainless steel passivation is a chemical treatment that removes free iron and other contaminants from the surface of machined, fabricated, or handled stainless steel components. By restoring the chromium-rich oxide layer, passivation improves the natural corrosion resistance of the base metal and reduces the risk of rust staining or pitting initiation in service.
At Fukar in Shah Alam, passivation is carried out in a controlled nitric acid or citric acid bath, followed by thorough rinsing and drying. The process is suitable for austenitic and duplex stainless steel parts used in food processing, pharmaceutical, marine, oil and gas, and architectural applications. We review material grade, surface condition, and project specification before selecting the acid concentration, temperature, and immersion time.
Common specifications include ASTM A967, ASTM A380, QQ-P-35, and AMS 2700. We can provide process certificates, bath analysis records, and passivation test reports to support customer quality documentation and audit requirements.
Typical Specifications
| Substrate | Stainless steel |
|---|---|
| Acid type | Nitric or citric |
| Process method | Immersion bath |
| Temperature range | 20 – 50 °C |
| Common standards | ASTM A967, AMS 2700 |
| Dwell time | Per material grade |
| Applications | Fittings, flanges, valves |
Controlled Process
Stainless Steel Passivation Steps
1. Pre-Clean
Degreasing and removal of machining oils, fingerprints, and shop soil.
2. Acid Bath
Controlled immersion in nitric or citric acid to dissolve free iron.
3. Water Rinse
Thorough rinsing to remove acid residues and neutralise the surface.
4. Dry & Inspect
Controlled drying and visual inspection for uniform passive surface.
Common Questions
Passivation FAQs
Why does stainless steel need passivation?
Machining and handling deposit free iron on the surface. Passivation removes this contamination and restores the protective chromium oxide layer.
Is passivation the same as pickling?
No. Pickling removes heavy scale and weld discolouration using stronger acids. Passivation is a lighter treatment that restores the passive layer without aggressive surface removal.
Which stainless steel grades can be passivated?
Most austenitic grades such as 304 and 316, plus duplex grades. Ferritic grades can also be treated with adjusted chemistry.
Can Fukar provide passivation certificates?
Yes. We can provide process certificates, bath analysis records, and inspection reports to support your quality plan.
Related Services
Stainless Steel Passivation Details
Technical notes and deeper process context for stainless passivation.
Read details →