Galvanized steel plate is to prevent corrosion on the surface of the steel plate to prolong its service life. A layer of metal zinc coating is plated on the surface of the steel plate. The zinc coated steel plate is called galvanized plate. Generally widely used in construction, home appliances, vehicles and vessels, container manufacturing, machinery and electrical industry.
So galvanized steel plate exposed to the air will produce what phenomenon, this article will be summarized for you.
Galvanized steel plate exposed to the air, as long as it will produce dry manic corrosion, wet cold corrosion and wet corrosion and other conditions.
Dry manic corrosion refers to the corrosion of steel in the air humidity below 30% of the ambient air surface does not produce continuous electrolyte water film. At this time, the corrosion rate of steel is relatively slow, but this kind of natural environment standard is less.
Wet and cold corrosion refers to the corrosion of steel in the ambient air where the air humidity is more than 30% and less than 100%. In this case, there is dust on the surface of the steel, and the rust layer has microholes and gaps, resulting in microscope absorption, resulting in shrinking water that the human eye can not see. The galvanic cell principle is generated in shrinking underwater, and the corrosion rate is relatively rapid.
Wet etching refers to the etching of galvanized steel plate when there is solidified and shrinking water visible to human eyes in the moist and cold air environment where the air humidity is more than 100%. In this case, the shrinkage water on the steel surface is thicker, so that the rate of oxygen diffusion outside the steel surface after melting is relatively slow, reducing the rate of corrosion. In fact, the corrosion of steel is closely related to the shrinkage water on the surface between the two, but also due to the presence of water, the CO2 in the water melts, so that the iron produces weak electrolyte, resulting in a series of weak electrolyte reactions.
As the CO2 in the gas continues to melt into the water, the reaction continues. Since the key product of the reaction is bright red, the material after the oxidation of iron air is generally called “red rust”. Red rust is very loose, very easy to melt, can not maintain the steel surface not to be again etched, promote the corrosion of steel until it is completely etched, it is the property of steel. Because of this, the steel must be coated with other metal material or metal material protective thickness to reasonably avoid corrosion of the steel.
The above is some corrosion characteristics of galvanized steel plate, want to know more knowledge can contact us.
Post time: Mar-03-2023