Alloyed zinc aluminum magnesium alloy coated steel plate and production method thereof

Abstract

The invention provides an alloyed zinc aluminum magnesium alloy coated steel plate and a production method thereof. The coating has an Fe content of not more than 5%, the coating surface contains an MgZn2 phase, which has a particle size of not greater than 5 micrometers. The coating surface is in the form of equiaxed grains, and in the coating, Mg accounts for 1.5-8wt%, aluminum accounts for 1.5-15wt%, and rare earth accounts for 0-0.2wt%. According to the production method, cold rolled strip steel is subjected to continuous annealing and hot dipping in a continuous hot dip galvanizing unit, and then alloy treatment is carried out on the hot-dip galvanized zinc aluminum magnesium steel plate. Chemically, a plating solution comprises 1.0-11wt% of Al, 0.5-5wt% of Mg, and the balance Zn and inevitable impurities. After the steel plate undergoes annealing by N2 containing 0.5%-30 vol % of H2, the steel plate is immersed in the plating solution at a temperature of 450-650DEG C, the steel plate enters a zinc pot at 420-580DEG C, and the immersion plating time of the steel plate in the plating solution is 1-10s. After air knife cooling, the zinc aluminum magnesium steel plate enters an alloying furnace to undergo alloying treatment, the alloying temperature is 450-650DEG C, the alloying time is 3-20s, and then the steel plate is cooled at a speed of 10-50DEG C / s. The steel plate provided by the invention ensures that the coating does not fall off in a complex forming process, and after forming, the zinc aluminum magnesium coating can put its excellent corrosion resistance to good use, thus prolonging the service life of components.

Description

technical field [0001] The invention belongs to the field of hot-dip galvanizing, and in particular relates to an alloyed zinc-aluminum-magnesium coated steel plate with excellent formability and good corrosion resistance and a production method thereof. Background technique [0002] In order to meet the increasing corrosion resistance requirements, in addition to hot-dip galvanized products, hot-dip aluminum, hot-dip tin-zinc, hot-dip aluminum-zinc alloy, hot-dip galvanized aluminum-magnesium coated steel sheets and other varieties have been developed. Galvanized aluminum-magnesium-coated steel sheets have been widely valued for their excellent corrosion resistance. Developed countries such as Japan, Europe and the United States have successively developed products such as ZM, Z6A3M, and Z10A3M. Patents CN101812653A, US6235410B1, etc. have developed zinc-based coatings containing aluminum and magnesium, which greatly improve corrosion resistance. Compared with the traditio...

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Problems solved by technology

Patent CN1310770A provides an alloyed galvanized steel sheet with good adhesion and excellent pressure forming performance, CN101353761A provides a TRIP steel sheet with an alloyed galvanized layer, and US6410163B1 provides a high-strength alloyed hot-dip galvanized sheet Steel sheets, but these patents are only applicable to galvanized sheets, and the alloying of zinc-aluminum-magnesium coatings has not been studied

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