SANJIU Standard cooling towers apply the latest type of Highly Corrossion-resistant coated steel sheet with a coating composition consisiting of zinc as the main substrate, in combination with Al(11%), Mg(3%), and a trace amount of silicon.This special material is named as 'SuperDyma' by Nippon Steel.
Corrosion Resistance of Flat Surfaces
Conventional hot-dip Zn-coated steel sheets also produce a protective film. However, this film is rough in texture, allowing the penetration of moisture and oxygen and a resultant growth of corrosion.
By contrast, the dense protective film formed on the surface of SuperDyma arrests the corrosion process and stabilizes corrosion behavior.
Specime
Type of coating
Coating mass
Surface treatment
Thickness
Hot-dip Zn- coated sheet
Zn
Z27
Special chromate treatment
1.6mm
SuperDyma
–3%Mg–0.2%Si Zn–11%Al
K18
Galvalume Steel Sheet
Zn–55%Al
AZ150
Test conditions: Cyclic corrosion test (JASO M609-91 method) Repetition of ① to ③ as a cycle ① Salt spray: 2 hours (5% NaCl, 35℃) ② Drying: 4 hours (60℃) ③ Wetting: 2 hours (50℃, humidity 95% or more)
◆Not only highly rust resistant on flat surfaces; ◆But also superiorly corrosion proof on cut-end surfaces, self 'recovered'. ◆In additional, of extremely high alkaline resistance.
The corrosion resistance of this innovative alloy coated steel is enhanced by the composite effect of adding aluminum, magnesium and silicon to the conventional zinc coating. Silicon, among other elements, is highly effective in inhibiting corrosion when combined with Magnesium.
Corrosion Resistance at Cut-end Surfaces
Results of Outdoor Exposure Tests
◆ In the actual exposure environment outdoors, a slight degree of initial red rust occurs on cut-end surfaces, but, after a while, a stable protective film covers the cut-end surface, thus virtually arresting further progress of corrosion in the long run.
◆ Red rust which occurs in the initial phase is arrested in progress, with time, by the effect of the protective film and, soon entirely covered by the film, becomes quite inconspicuous.
Superior Raw Materials, Advanced Tech Design, Precise Fabricating Equipments, All These Created Reliable Cooling Towers of SANJIU!