Composite plated steel sheet having excellent post-formation corrosion resistance, and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-12448674-B2
Application number	US-202118267319-A
Country	US
Kind code	B2
Filing date	Dec 10, 2021
Priority date	Dec 18, 2020
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

A composite plated steel sheet including a base steel sheet; a Zn—Mg—Al-based plating layer provided on at least one surface of the base steel sheet; and a resin layer provided on at least one surface of the Zn—Mg—Al-based plating layer. The resin layer includes a base resin and resin powder. A hardness of the resin powder is 1.1 to 2 times that of the base resin.

First claim

The invention claimed is:

1. A composite plated steel sheet, comprising:
a base steel sheet;
a Zn—Mg—Al-based plating layer provided on at least one surface of the base steel sheet; and
a resin layer provided on at least one surface of the Zn—Mg—Al-based plating layer,
wherein the resin layer includes a base resin and resin powder,
the resin powder includes polyurethane-based resin powder, and
a hardness of the resin powder is 1.1 to 2 times that of the base resin.

2. The composite plated steel sheet of claim 1 , wherein the base resin is at least one selected from the group consisting of a polyester-based resin, a urea-based resin, an epoxy-based resin, a urethane-based resin, and an ethylene-based resin.

3. The composite plated steel sheet of claim 1 , wherein the resin powder is included in an amount of 5 to 30 vol % based on a volume of the resin layer.

4. The composite plated steel sheet of claim 1 , wherein an average surface area of the resin powder is 30 to 700 μm 2 .

5. The composite plated steel sheet of claim 1 , wherein the resin layer further includes at least one of a crosslinker and a pigment,
the crosslinker is at least one selected from the group consisting of a melamine resin and an isocyanate resin, and
the pigment is at least one selected from the group consisting of titanium oxide and a rust-preventive pigment.

6. The composite plated steel sheet of claim 5 , wherein the resin layer includes 30 to 65 wt % of a base resin, 4 to 25 wt % of resin powder, 3 to 8 wt % of crosslinker, and 5 to 25 wt % of pigment, based on a total weight of the resin layer.

7. The composite plated steel sheet of claim 1 , wherein the plating layer contains, by wt %, Mg: 1.0 to 6.0%, Al: 1.5 to 13%, Si: 0.3% or less (excluding 0%), and balance being Zn and other unavoidable impurities,
an average content of Fe at a ½ point of the plating layer in a thickness direction is 0.07% or less (including 0%), and
a ratio of Al and Mg (Al/Mg) is 0.7 to 3.0.

8. The composite plated steel sheet of claim 1 , wherein, among the plating layer, an area containing a MgZn 2 phase is 10 to 80% in phase fraction, wherein the area containing the MgZn 2 phase means an area in which the MgZn 2 phase is present alone or present as alloy phases selected from Al—MgZn 2 , Zn—Al—MgZn 2 , and Zn—MgZn 2 .

9. The composite plated steel sheet of claim 1 , further comprising:
a Fe—Al-based inhibition layer provided between the base steel sheet and the plating layer.

10. A method for manufacturing a composite plated steel sheet, comprising:
preparing a base steel sheet;
forming a Zn—Mg—Al-based plating layer on at least one surface of the base steel sheet; and
forming a resin layer containing a base resin and resin powder on at least one surface of the Zn—Mg—Al-based plating layer,
wherein a hardness of the resin powder is 1.1 to 2 times that of the base resin, and
wherein the resin powder includes polyurethane-based resin powder.

11. The method of claim 10 , wherein the base resin is at least one selected from the group consisting of a polyester-based resin, a urea-based resin, an epoxy-based resin, a urethane-based resin, and an ethylene-based resin.

12. The method of claim 10 , wherein the resin powder is included in an amount of 5 to 30 vol % based on a volume of the resin layer.

13. The method of claim 10 , wherein an average surface area of the resin powder is 30 to 700 μm 2 .

14. The method of claim 10 , wherein the resin layer further includes at least one of a crosslinker and a pigment,
the crosslinker is at least one selected from the group consisting of a melamine resin and an isocyanate resin, and
the pigment is at least one selected from the group consisting of titanium oxide and a rust-preventive pigment.

15. The method of claim 14 , wherein the resin layer includes 30 to 65 wt % of a base resin, 4 to 25 wt % of resin powder, 3 to 8 wt % of crosslinker, and 5 to 25 wt % of pigment, based on a total weight of the resin layer.

Assignees

• Posco Co Ltd

Inventors

• Sohn Il-Ryoung

Classifications

• C23C2/40

  Plates; Strips · CPC title

• C23C2/265

  by applying solid particles to the molten coating · CPC title

• C23C2/12

  Aluminium or alloys based thereon · CPC title

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title

• C22C38/06

  containing aluminium · CPC title