Production method for aluminum, magnesium and zinc coated steel plate

Abstract

A production method for an aluminum, magnesium and zinc coated steel plate comprises the following steps of alkali washing, water washing, acid pickling, water washing, coating auxiliary treatment, drying, hot zinc coating, cooling and finished product obtaining. According to alkali washing, NaOH, Na2CO3 and Na3PO4 are prepared into a 20%-25% solution according to the concentration of 1:1:1, alkali liquor is heated to range from 70 DEG C to 80 DEG C, and oil dirt on the surface of the steel plate is removed through the alkali liquor. Hot zinc coating liquor is prepared from, by mass percent, 50%-58% of aluminum, 1.2%-1.8% of silicon, 1%-3% of magnesium and the balance zinc. A solvent covering agent is added in the hot zinc coating process for protection, and is prepared from MgCl2, KCl and MgF2. Coating auxiliary treatment is adopted, so that the phenomena of missing coating and joint forming are reduced; and the solvent covering agent is further added in the hot zinc coating process for protection, so that aluminum, magnesium and zinc surface oxidization is avoided, and the adhesion degree of a coating layer is effectively guaranteed.

Description

technical field [0001] The invention belongs to the technical field of hot-dip and spray coating, and in particular relates to a production method of aluminum-magnesium-zinc plated steel plate. Background technique [0002] Al-Zn-Mg steel plate is a new type of high-corrosion-resistant coated steel plate. The galvanized layer is mainly composed of zinc, which is composed of zinc plus aluminum, magnesium and a small amount of silicon. Due to the compound effect of these added elements, its corrosion resistance is further improved. Inhibitory effect. In addition, it has excellent processing performance under severe conditions (stretching, stamping, bending, paint welding, etc.), and the coating has high hardness and excellent damage resistance. Compared with ordinary galvanized and galvalume products, it can achieve better corrosion resistance with less plating adhesion. Due to this super corrosion resistance, it can be used instead of stainless steel in some fields. [00...

AI Technical Summary

Problems solved by technology

[0003] It is precisely because of the addition of alloying elements such as aluminum and magnesium that the chemical reaction and adhesion between the coating and the steel substrate, the solidification process of the coating during the cooling process after hot-dip plating, and the shape and distribution of each phase after solidification have all occurred. Fundamental changes, so the complexity and difficulty of the hot-dip plating process have greatly increased, which is reflected in the increase in the fluidity of the plating solution, which makes zinc flow ripples appear on the surface of the steel plate, making it more difficult or even impossible to obtain a thicker coating; The addition of aluminum improves the corrosion resistance of the coating, but at the same time deteriorates the processing performance; the addition of silicon, together with magnesium, improves the corrosion resistance and processing performance, but at the same time increases the surface defects