Composite zinc-aluminum alloy coating material and hot-dip plating method

Abstract

The invention discloses a composite zinc-aluminum alloy coating material and a hot-dip plating method. A eutectoid composition Zn-Al-Si-Mg-Ti alloy coating for hot-dip plating is prepared and comprises, by mass percentage, 10-30% of Al, 0.1-1% of Si, 0.04-1% of Ti, not larger than 5% of Mg and the balance Zn. A plating solution alloy is melted through a molten salt covering method; a part to be electroplated is put into a zinc pot and pre-reduced in hydrogen-nitrogen mixed gas with the reducing atmosphere of 5-50%, the reducing temperature ranges from 500 DEG C to 680 DEG C, the preheating time ranges from 3 min to 10 min, the zinc pot temperature is controlled within the range of 550-640 DEG C, and the dip plating time is controlled within the range of 3s-30min; and after a plate is taken out of the zinc pot, the thickness of the coating is controlled through an air knife, meanwhile the coating is cooled, and the expected hot-dip plating plate is obtained. By the adoption of the composite zinc-aluminum alloy coating material and the hot-dip plating method, the obtained coating is level in surface, and the amount of bottom slag in a plating solution is small.

Description

technical field [0001] The invention relates to a metal material and a coating process thereof, in particular to a hot-dip coating material and an alloy coating preparation method thereof, which are applied in the technical field of hot-dip coating technology. Background technique [0002] The hot-dip galvanized aluminum coating combines the durable protection of aluminum and the anodic protection of zinc. It not only has longer atmospheric corrosion resistance, but also has better coating performance and better resistance to high temperature oxidation. [0003] Hot-dip galvanizing is widely used in bridges, building steel structures, automobiles, mining machinery and shipbuilding industries. At present, the relatively mature aluminum-zinc alloy coatings mainly include Galvalume of Bethlehem Iron and Steel Company, Galfan of World Lead and Zinc Association, and Nippon Iron and Steel Company. Among them, high-aluminum Galvalume is the most common, but in the process of hot-di...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problems of the prior art, the object of the present invention is to overcome the deficiencies in the prior art, and provide a composite zinc-aluminum alloy coating material and a hot-dip coating method. On the basis of a low-aluminum zinc-rich alloy, Mg element or Adding Mg and Ti alloy elements at the same time can not only solve the problem that the corrosion resistance of the coating is reduced, but also improve the surface quality of the coating and provide the preparation process parameters. Therefore, the hot-dip Zn-Al-Si-Mg coating of the present invention is adopted Alloy coating or hot-dip Zn-Al-Si-Mg-Ti alloy coating has excellent comprehensive properties

The invention solves the problem of poor corrosion resistance of low-aluminum-zinc-rich alloys. By adding alloy elements Mg and Ti, the structure of the coating is changed, and finally the corrosion resistance of the coating is improved and the surface quality of the product is improved.

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