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Minghan Chemical
Passivation & Corrosion Resistance

Stainless Steel Passivation Before-and-after Comparison

For stainless steel parts with weld discoloration, surface oxidation, light rust spots and insufficient corrosion resistance, Minghan established a cleaning, activation, passivation, rinsing and drying process to improve surface cleanliness and corrosion resistance.

2026-03-08 South China equipment plant Stainless welded parts
Stainless Steel Passivation Before-and-after Comparison Before Passivation
Stainless Steel Passivation Before-and-after Comparison After Passivation

Case Overview

The customer’s stainless steel hardware and equipment components showed weld discoloration, local darkening, surface residues and potential rust risk after fabrication. Minghan Chemical provided a stainless steel passivation process based on material condition, surface contamination and service environment, helping improve corrosion resistance while keeping the original stainless steel appearance stable.

Customer Challenge

The workpieces had machining oil, weld marks, oxide film and localized rust spots. Direct shipment could lead to unstable appearance, rust during storage or transport, and insufficient corrosion resistance. The customer also required a process suitable for batch production with consistent surface quality.

Solution

Minghan recommended a process of degreasing, rinsing, surface activation, stainless steel passivation, thorough rinsing and drying. The pretreatment removes oil, loose rust and surface contamination, while the passivation step forms a stable protective film on the stainless steel surface.

Result

After treatment, the parts showed a cleaner and more uniform stainless steel surface. Weld discoloration and oxidation marks were visibly reduced, and the passivation film improved corrosion resistance stability, reducing the risk of rust during storage, transport and use.

Implementation Process

01

Sample review

Confirm stainless steel grade, oxidation level, weld marks and corrosion resistance target.

02

Pretreatment cleaning

Remove machining oil, dust, fingerprints and surface contaminants for stable passivation.

03

Passivation treatment

Match chemical concentration, temperature and treatment time to form a uniform passive film.

04

Rinsing and drying

Rinse thoroughly and dry promptly to reduce water marks, residues and secondary contamination.

05

Result verification

Check appearance, cleanliness and corrosion resistance to define repeatable batch parameters.

Case Information

Surface condition

Improved from dark oxidation and local rust spots to a cleaner, more uniform stainless steel finish

Corrosion resistance

More stable passive film helps reduce rust risk during storage and service

Process compatibility

Suitable for immersion, circulation or batch basket processing

Delivery value

Reduces manual rework and improves batch shipment consistency

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Stainless Steel Passivation Case Brief

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