CN-118621245-B - Zinc-aluminum-magnesium coating, zinc-aluminum-magnesium coating steel plate, preparation method of zinc-aluminum-magnesium coating steel plate and automobile outer plate

Abstract

The application relates to a zinc-aluminum-magnesium coating, a zinc-aluminum-magnesium coating steel plate and a preparation method thereof, and an automobile outer plate, wherein the zinc-aluminum-magnesium coating comprises Al, mg, ti, B, RE parts by mass of Zn, the content of Al is 0.8% -2.5%, the content of Mg is 0.8% -2.5%, the following relational expression is satisfied that [ Al ] - [ Mg ] > 0, [ Ti ] + [ B ] + [ RE ] < 50ppm, and the equivalent diameter of intermetallic compound particles on the surface of the zinc-aluminum-magnesium coating is not more than 300 microns. The application solves the technical problems that the surface of the existing zinc-aluminum-magnesium plated steel plate is easy to generate local high points and stamping bright spots during stamping.

Inventors

• Jiang guangrui
• ZHANG HUANYU
• MA XINGJIANG
• WANG SONGTAO
• LI YAN
• ZHANG HAO
• XU CHENGLIANG
• LIU GUANGHUI
• TENG HUAXIANG
• HAN BIN
• SHANG TING

Assignees

• 首钢集团有限公司

Dates

Publication Date

20260512

Application Date

20240607

Claims (9)

1. 1. The zinc-aluminum-magnesium coating is characterized by comprising the following chemical components: Al, mg, ti, B, RE and Zn, wherein, in mass fraction, The content of Al is 0.8-2.5%, the content of Mg is 0.8-2.5%, And satisfies the following relation that [ Al ] - [ Mg ] > 0, [ Ti ] + [ B ] + [ RE ] < 50 ppm, and the RE content is not more than 10 ppm; The equivalent diameter of intermetallic compound particles on the surface of the zinc-aluminum-magnesium coating is not more than 300 micrometers; Wherein [ Al ] represents the mass fraction of Al, [ Mg ] represents the mass fraction of Mg, [ Ti ] represents the mass fraction of Ti, [ B ] represents the mass fraction of B, and [ RE ] represents the mass fraction of RE.
2. 2. The zinc-aluminum-magnesium plating layer according to claim 1, wherein the equivalent diameter of intermetallic particles on the surface of said zinc-aluminum-magnesium plating layer is not more than 100 μm.
3. 3. The zinc-aluminum-magnesium plating layer according to claim 1, wherein the content of Al and the content of Mg satisfy the following relation: [Al]-[Mg]≥0.5% wherein [ Al ] represents the mass fraction of Al and [ Mg ] represents the mass fraction of Mg.
4. 4. The zinc-aluminum-magnesium plating layer according to claim 1, wherein the kind of the intermetallic compound includes one or more of Fe-Zn compound, zn-RE compound, fe-Zn-Al compound, al-Ti compound, al-B compound, al-Ti-B compound, and Mg-Zn compound.
5. 5. A zinc-aluminum-magnesium plated steel sheet characterized by comprising a steel substrate and the zinc-aluminum-magnesium plated layer according to any one of claims 1 to 4 attached to at least a part of the surface of the steel substrate.
6. 6. A method of preparing the zinc-aluminum-magnesium plated steel sheet according to claim 5, comprising: Obtaining a steel matrix; and carrying out hot dip plating on the steel matrix, and then carrying out surface treatment to obtain the zinc-aluminum-magnesium plated steel plate.
7. 7. The method of claim 6, wherein the surface treatment comprises mild rolling.
8. 8. The method of claim 7, wherein the lightly rolled elongation is 0.6% -1.5%.
9. 9. An automobile outer panel, wherein the raw material of the automobile outer panel comprises the zinc-aluminum-magnesium plated steel sheet according to claim 5.

Description

Zinc-aluminum-magnesium coating, zinc-aluminum-magnesium coating steel plate, preparation method of zinc-aluminum-magnesium coating steel plate and automobile outer plate Technical Field The application relates to the technical field of coating, in particular to a zinc-aluminum-magnesium coating, a zinc-aluminum-magnesium coating steel plate, a preparation method thereof and an automobile outer plate. Background The zinc-aluminum-magnesium coated steel plate is a novel high corrosion-resistant alloy coated steel plate. The plating layer is developed on the basis of the traditional pure zinc plating layer, and magnesium element and aluminum element are added into the plating layer, so that the plane corrosion resistance and notch corrosion resistance of the plating layer are obviously improved, and the plating layer can be widely used for manufacturing automobiles, household appliances, building outer wall surfaces and the like. Zinc aluminum magnesium plating has been widely used in the manufacture of automotive bodies. However, inclusion defects are easy to occur on the surface of the zinc-aluminum-magnesium coating, so that local high points and stamping bright spots are easy to occur on the surface of the automobile outer plate during stamping, and the actual application of users cannot be met. The zinc-aluminum-magnesium plating layer contains more alloy elements compared with the traditional pure zinc plating layer and zinc-iron alloy plating layer. The addition of these alloying elements can introduce unexpected impurity elements. The impurity element may form inclusions in the plating layer that affect the press quality. Disclosure of Invention The application provides a zinc-aluminum-magnesium plating layer, a zinc-aluminum-magnesium plating layer steel plate and a preparation method thereof, and an automobile outer plate, so as to solve the technical problem that the surface of the existing zinc-aluminum-magnesium plating layer steel plate is easy to generate local high points and stamping bright spots during stamping. In a first aspect, the application provides a zinc-aluminum-magnesium plating layer, which comprises the following chemical components: Al, mg, ti, B, RE and Zn, wherein, in mass fraction, The content of Al is 0.8-2.5%, the content of Mg is 0.8-2.5%, And satisfies the following relation that [ Al ] - [ Mg ] > 0, [ Ti ] + [ B ] + [ RE ] < 50ppm; The equivalent diameter of intermetallic compound particles on the surface of the zinc-aluminum-magnesium coating is not more than 300 micrometers; Wherein [ Al ] represents the mass fraction of Al, [ Mg ] represents the mass fraction of Mg, [ Ti ] represents the mass fraction of Ti, [ B ] represents the mass fraction of B, and [ RE ] represents the mass fraction of RE. Optionally, the equivalent diameter of intermetallic compound particles on the surface of the zinc-aluminum-magnesium plating layer is not more than 100 micrometers. Optionally, the content of Al and the content of Mg satisfy the following relation: [Al]-[Mg]≥0.5% wherein [ Al ] represents the mass fraction of Al and [ Mg ] represents the mass fraction of Mg. Optionally, the RE content is not more than 10ppm. Optionally, the intermetallic compound includes a Fe-Zn compound, a Zn-RE compound, a Fe-Zn-Al compound, an Al-Ti compound, an Al-B compound, an Al-Ti-B compound, and a Mg-Zn compound. In a second aspect, the present application provides a zinc-aluminum-magnesium plated steel sheet comprising a steel substrate and a zinc-aluminum-magnesium plated layer according to the first aspect attached to at least part of the surface of the steel substrate. In a third aspect, the present application provides a method for preparing the zinc-aluminum-magnesium plated steel sheet according to the second aspect, the method comprising: Obtaining a steel matrix; and carrying out hot dip plating on the steel matrix, and then carrying out surface treatment to obtain the zinc-aluminum-magnesium plated steel plate. Optionally, the surface treatment comprises mild rolling. Optionally, the elongation of the slight rolling is 0.6% -1.5%. In a fourth aspect, the application provides an automobile outer plate, wherein the raw material of the automobile outer plate comprises the zinc-aluminum-magnesium plated steel plate in the second aspect. Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages: The zinc aluminum magnesium plating layer provided by the embodiment of the application limits the content of Al, provides high-quality atmospheric corrosion resistance for the plating layer, prevents the surface of the plating layer from cracking to cause dense polishing bright spots, limits the content of Mg, improves the atmospheric corrosion resistance of the plating layer, prevents polishing bright spots after the plating layer is stamped due to overlarge size of Mg-Zn compounds, limits the content of Al in the plating layer to be no