GB/T 25149-2010Quality test method of passive film on carbon steel of chemical cleaning for industrial equipment - Red dot method (English PDF)

3.1 Passivation film passivefilm

To prevent the metal surface to be cleaned twice rust, a temporary protective film by chemical metal surface.

3.2 Red dot liquid

Designed to test carbon steel surface passivation film quality of the test solution. Solution itself is blue, red spots will form a passivation film is destroyed.

3.3 Cleaning system

While accepting cleaning device or system is composed of a plurality of devices, components and piping component.

4. Summary

Carbon steel surface passivation after dropping liquid on the red dot, red dot fluid can damage the passive film, the following reaction. Fe Cu2 = Cu -> Fe2.

After the destruction of the passive film formed elemental copper red spots, red spots with a stopwatch record was changed from blue to red time, according to the disappearance of the blue to red

Color length of time to determine the quality of the passivation film.

5.1

Test methods used in the reagents and water, did not indicate when the other requirements, refer to analytically pure reagents and GB/T 6682 provisions of the three steam

Distilled water.

Solution preparation and products 5.2 Test required, in the absence of other provisions indicated, was prepared according to the provisions of GB/T 603's.

5.3

Reagents and materials required for the test are as follows.

--- Copper sulfate pentahydrate;

---Sodium chloride;

--- Hydrochloric acid. 0.1mol/L;

GB/T 29465-2023 | GB/T 7996-2020 | HG/T 20537.3-1992 | GB/T 25147-2010 | GB/T 25146-2010 | GB/T 25145-2010 | […]