Zn-Al-Mg hot-dip steel plate with high corrosion resistance, and production method thereof

Abstract

The invention discloses a Zn-Al-Mg hot-dip steel plate with high corrosion resistance, and a production method thereof. The Zn-Al-Mg hot-dip steel plate comprises a baseplate and a coating on the baseplate, and is characterized in that the chemical components of the coating comprise, by mass, 1.8%-2.3% of Al, 1.2%-1.8% of Mg, 0.01%-0.08% of Re, 0.003%-0.008% of Cu and the balance Zn and other inevitable impurities, wherein the Cu is added to plating solutions in a nanometer form during melting of the plating solutions. The Cu in the coating of the steel plate is added in a nano-copper form during melting of the plating solutions; since the temperature of Zn liquid is lower during adding of the Cu, the shape of Cu particles can be ensured; by taking advantage of the characteristic of fine dispersion of the Cu particles, the Cu particles play a role in strengthening of precipitation, so that the hardness of the coating is improved; and by adding of rare earth Re, the coating structure can be fined, and the fluidity of the plating solutions is improved, so that the corrosion resistance of the coating can be improved effectively. The coating structure of a product obtained with the method is primary Zn, Zn / MgZn2 binary eutectic, Zn / Al / MgZn2 ternary eutectic and nano-copper; and the corrosion resistance is equal to 10-15 times the corrosion resistance of a pure zinc plate 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 new ty...

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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 new corrosion-resistant coating products have also been developed internationally, such as Galvalume (55%Al-43.4%Zn-1.6%Si), its corrosion resistance The performance can reach 2 to 6 times that of ordinary pure galvanized sheet, but its immersion 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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