High corrosion resistance zinc-aluminum-magnesium hot-dip galvanized steel sheet and production method thereof

Abstract

The invention discloses a high-corrosion-resistant zinc-aluminum-magnesium hot-dipped steel plate and a production method thereof, which includes a substrate and a coating coated on the substrate, and is characterized in that the mass percentage of the chemical composition of the coating is: Al 1.8~2.3%, Mg 1.2~1.8%, RE 0.01~0.08%, Cu 0.003~0.008%, the balance is Zn and other unavoidable impurities; Cu is added to the plating solution in nanometer form when the plating solution melts . Cu in the coating of this steel plate is added in the form of nano-copper when the plating solution melts. Since the temperature of the zinc solution is low when it is added, the morphology of Cu particles can be guaranteed, and its fine and dispersed characteristics can play a role in precipitation strengthening, thereby Improve the hardness of the coating; the addition of rare earth RE can refine the coating structure and improve the fluidity of the plating solution, thereby more effectively improving the corrosion resistance of the coating. The structure in the coating of the product gained by this method is: primary Zn, Zn / MgZn 2 Binary eutectic, Zn / Al / MgZn 2 Ternary eutectic and nano-copper; the corrosion resistance is equivalent to 10 to 15 times that of pure zinc plates of the same thickness.

Description

technical field [0001] The invention relates to a coated steel plate, in particular to a high-corrosion-resistant zinc-aluminum-magnesium hot-dipped steel plate and a production method thereof. Background technique [0002] Steel is the largest and most widely used metal material in the world. It has a variety of excellent properties, such as: good toughness, high strength, and high cost performance; but it also has some shortcomings, the most prominent of which is that it is easily eroded by air at low temperature and humidity, and easily eroded by air at high temperature. It is oxidized by oxygen and suffers from problems such as accelerated corrosion rate in acidic environment. Therefore, the problem of anti-corrosion of steel is very important, and metal anti-corrosion technology has always been a major research topic in the field of metal materials. [0003] The commonly used protective methods include galvanizing and painting, but the industry urgently needs a coatin...

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Problems solved by technology

Studies have found that adding alloy elements to the coating can effectively improve the corrosion resistance of the product, and a variety of corrosion-resistant coating products have also been developed internationally, such as Galvalume (55%Al-43.4%Zn-1.6%Si), its corrosion resistance It can reach 2 to 6 times that of ordinary pure galvanized sheet, but its dipping temperature is high, energy consumption is large, and the equipment is easily damaged

For example, Galfan (Zn-5%Al-RE), its corrosion resistance is 2 to 3 times that of pure galvanized layer, especially in industrial atmosphere and marine atmosphere, and its coating performance is also better than galvanized sheet; but its welding performance And the appearance of the coating is insufficient, and the production cost is high and the mechanical properties are poor

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