What are the anti-corrosion treatment methods for stainless steel bridge frames?

Basic anti-corrosion: passivation treatment (restoring the original anti-corrosion layer)

This is the anti-corrosion method for stainless steel bridge foundation, aimed at repairing the damaged passivation film during processing (cutting, welding, polishing).

First, remove oil, rust, and polish the treated area to ensure a clean and impurity free surface;

Soak or apply passivation solution, control temperature (room temperature~50 ℃) and time (10-30 minutes);

Rinse with clean water, air dry before use;

Prioritize the use of chromium free passivation solution, which meets environmental requirements.

Process principle: Utilize passivation solution (commonly nitric acid+dichromate system, or environmentally friendly chromium free passivation solution) to undergo oxidation reaction with the surface of stainless steel, generating a uniformly thick and dense chromium rich passivation film to prevent oxygen and corrosive media from contacting the substrate.

Applicable scenarios: End face treatment after bridge cutting and welding; Repair of scratched areas during installation; Pre factory anti-corrosion treatment under standard conditions.

Operation points:

Enhanced anti-corrosion: electrolytic polishing (improves surface smoothness+anti-corrosion properties)

It belongs to surface finishing treatment, which can improve aesthetics and enhance anti-corrosion ability, suitable for scenes with high requirements for cleanliness and aesthetics.

Process principle: Using stainless steel bridge as the anode, placing it in electrolytic polishing solution and applying electricity, using electrochemical action to dissolve the small protrusions on the surface, achieving a mirror like or brushed effect on the surface, while forming a more uniform passivation film.

Core advantage: After improving the surface smoothness, it is not easy to accumulate dust, accumulate dirt and reduce the adhesion of corrosive media; The polished passivation film is denser, and its resistance to acid and alkali, as well as salt spray, is increased by more than 30% compared to ordinary passivation.

Applicable scenarios: Hospitals, food workshops, pharmaceutical factories, commercial buildings and other places with high demand for cleanliness/aesthetics.

Extreme environmental anti-corrosion: coating protection (composite anti-corrosion solution)

For highly corrosive environments such as coastal heavy salt spray and chemical strong acid alkali areas, coating protection is added on the basis of passivation treatment to form a dual protection of "passivation film+coating".

Fluorocarbon coating: With strong weather resistance and corrosion resistance, it can withstand strong acids, alkalis, and ultraviolet radiation. Its service life can reach more than 20 years and is suitable for extreme outdoor environments;

Polytetrafluoroethylene (PTFE) coating: resistant to high temperatures, chemical corrosion, low friction coefficient, suitable for scenarios with corrosive media erosion;

Stainless steel special anti-corrosion paint: It is necessary to use a special paint with strong adhesion to stainless steel to prevent ordinary paint from peeling off.

Common coating types:

Operation points: Before coating construction, it is necessary to ensure that the surface of the bridge is clean, dry, and passivated; The coating thickness should be uniform to avoid missed coating and sagging.