Galvanizing method of hot dip galvanizing steel plate

Abstract

The invention pertains to the field of hot-dip galvanized steel sheet manufacturing; the technical problem to be solved is to provide a production method of a hot-dip galvanized steel sheet. The production method specifically comprises the steps that: a steel plate is pickled and annealed, and hot-dip galvanizing operation is carried out; during the operation, the temperature of starting to the plate is 455 to 465 DEG C; the plating temperature in the zinc pot is 450 to 460 DEG C; Fe content in plating bath is less than 0.03 percent; Al content in plating bath is 0.21 to 0.25 percent; the speed of machine unit is 100 to 110m / min; the cooling speed of the steel sheet is 0 percent; depth to span temperature is 235 to 245 DEG C. By adopting the technical conditions, the ratio Al / Zn of atomic concentration of Al and Zn in Fe-Al intermediate layer is larger than 0.9; and the circumstances that Gamma phase and Delta phase are relatively thin and Xi phase is small can not be formed in plating layer, and the most part of the plating layer is made up of Eta phase, and the crystal grain Zn (002) with optimized orientation is formed, thus causing the performance of attachment, scratch resistance, wear resistance to be greatly improved.

Description

Contents of the invention [0001] The invention belongs to the field of hot-dip galvanized steel sheet manufacturing, and in particular relates to a method for galvanizing a hot-dip galvanized steel sheet with good coating adhesion. Background technique [0002] Due to its good corrosion resistance, excellent coating performance and clean appearance, hot-dip galvanized steel sheets have been widely used in manufacturing industries such as household appliances and automobile body panels. The requirements for the hot-dip galvanized steel coating are strong adhesion between the coating and the substrate, and it will not fall off when stamping and deformation. In addition, it must have good welding performance, corrosion resistance and phosphating performance to ensure the adhesion of the paint film and after painting. corrosion resistance. However, there are problems such as powdering and peeling of the coating during the stamping process of the hot-dip galvanized steel sheet, ...

AI Technical Summary

Problems solved by technology

If the solubility of Zn in the Fe-Al intermediate transition layer reaches supersaturation and a zinc-rich solid solution is formed, the absolute content of Al in the intermediate layer does not decrease at this time, but the percentage of Al decreases significantly, and at the same time because of the zinc Supersaturation destroys the homogeneity of the Fe-Al intermediate transition layer, thus causing the intermediate layer to lose its adhesion and prevent diffusion, and to form a thicker Fe-Zn alloy layer, so that the adhesion of the zinc layer is simultaneously go bad

[0006] In the prior art, the adhesion between the coating and the steel base is improved by changing the composition of the steel sheet or by controlling the surface roughness of the hot-dip galvanized steel sheet to form a coating on the surface, but no good effect has been achieved. The method of improving the adhesion between the coating and the steel base by using the composition and structure

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