US-12618139-B2 - Manufacturing method for plated steel material having excellent adhesion to plating and corrosion resistance

US12618139B2US 12618139 B2US12618139 B2US 12618139B2US-12618139-B2

Abstract

Provided is a method of manufacturing a Zn—Mg alloy plated steel having excellent plating adhesion and corrosion resistance. The method includes: sequentially forming a first Zn plating layer, a second Mg plating layer, and a third Zn plating layer on base steel by a physical vapor deposition (PVD) method to provide a plated steel material; heating the plated steel material for alloying heat treatment to provide an alloy plated steel material; and cooling the alloy plated steel material. In the providing of the plated steel material, the second Mg plating layer has a thickness of 30% to 35% of the sum of thicknesses of the first Zn plating layer, the second Mg plating layer, and the third Zn plating layer, and the first Zn plating layer has a thickness of 1.1 to 4 times a thickness of the third Zn plating layer.

Inventors

Seok-Jun Hong
Woo-Sung Jung

Assignees

POSCO CO., LTD

Dates

Publication Date: 20260505
Application Date: 20240823
Priority Date: 20181219

Claims (5)

1 . A method of manufacturing a Zn—Mg alloy plated steel having excellent plating adhesion and corrosion resistance, the method comprising: sequentially forming a first Zn plating layer, a second Mg plating layer, and a third Zn plating layer on a base steel by a physical vapor deposition (PVD) method to form a plated steel material on the base steel; after forming the plated steel material, heating the plated steel material for alloying heat treatment to form an alloy plated steel material on the base steel; and cooling the alloy plated steel material, wherein the second Mg plating layer has a thickness of 30% to 35% of a total thickness of the first Zn plating layer, the second Mg plating layer, and the third Zn plating layer, the first Zn plating layer has a thickness of 1.1 to 4 times a thickness of the third Zn plating layer, and the first Zn layer has a thickness exceeding 2 μm.
2 . The method of claim 1 , wherein the total thickness is less than 10 μm.
3 . The method of claim 1 , wherein the sequentially forming includes: performing a first intermediate cooling of the first Zn plating layer to room temperature after forming the first Zn plating layer; performing a second intermediate cooling of the second Mg plating layer to room temperature after forming the second Mg plating layer; and performing a third intermediate cooling of the third Zn plating layer to room temperature after forming the third Zn plating layer.
4 . The method of claim 1 , wherein the heating the plated steel material includes: heating the plated steel material in a temperature range of 180° C. to 220° C. for 120 seconds to 160 seconds.
5 . The method of claim 1 , wherein the cooling the alloy plated steel material includes: cooling the alloy plated steel material to the room temperature at a cooling rate of 5 to 15° C./s.

Description

TECHNICAL FIELD The present disclosure relates to a Zn—Mg alloy plated steel and a method of manufacturing the same, and more particularly, to a Zn—Mg alloy plated steel material which secures both plating adhesion and corrosion resistance, and a method of manufacturing the same. BACKGROUND ART A galvanizing method inhibiting corrosion of iron through a cathodic method has excellent anti-corrosion efficiency and economic feasibility and has been widely used in preparing steel materials having high anti-corrosion properties. A zinc plated galvanized steel material has sacrificial corrosion protection properties in which zinc, having an oxidation-reduction potential lower than iron, is first corroded when exposed to a corrosive environment, thereby inhibiting corrosion of the steel material, and in addition, as zinc of a plating layer is oxidized, dense corrosion products are formed on a surface of a steel sheet to block the steel material from an oxidizing environment, thereby improving corrosion resistance of the steel material. However, air pollution has increased in line with industrial advancement and a corresponding corrosive environment has been intensified, and due to stricter regulations against resource and energy saving, the need to develop a steel material having improved excellent corrosion resistance as compared to existing galvanized steel sheets has increased, and as part of that, various studies have been conducted on Zn—Mg alloy plated steel in the art. However, the currently developed Zn—Mg alloy plated steel materials involve many problems such as peeling during machining due to poor adhesion with a base material, and in order to solve such a problem, various methods such as changing a composition of a plating layer, configuring multiple plating layers, configuring an adhesive surface between a plating layer and a base material, and the like, have been proposed but the problem of a degradation of plating adhesion is yet to be overcome. RELATED ART DOCUMENT (Patent document 1) Korean Patent Registration No. 10-0775241 (published on Nov. 12, 2007) DISCLOSURE Technical Problem An aspect of the present disclosure may provide a Zn—Mg alloy plated steel material having excellent plating adhesion and corrosion resistance and a manufacturing method thereof. The subject of the present disclosure is not limited to the above description. A person skilled in the art would have no difficulty in understanding an additional subject of the present disclosure from the general contents of the present disclosure. Technical Solution According to an aspect of the present disclosure, a Zn—Mg alloy plated steel material having excellent plating adhesion and corrosion resistance includes: base steel and a plating layer formed on a surface of the base steel, wherein the plating layer includes a Zn single phase, a Mg single phase, a MgZn2 alloy phase and Mg2Zn11 alloy phase, the Zn single phase is included in the plating layer in a proportion of 15 volume % to 19 volume %, and a proportion of the Zn single phase in a lower t/2 region of the plating layer adjacent to the base steel is greater than a proportion of the Zn single phase in an upper t/2 region of the plating layer adjacent to a surface layer portion of the plating layer where t is a thickness (μm) of the plating layer. The Mg single phase may be included in the plating layer in a proportion of 13 volume % to 20 volume %. The MgZn2 alloy phase may be included in the plating layer in a larger proportion than the Mg2Zn11 alloy phase. The Mg2Zn11 alloy phase may be included in the plating layer in a proportion of 18 to 22 volume %. The plating layer may have a thickness (t) of 2 μm to 10 μm. According to an aspect of the present disclosure, a method of manufacturing a Zn—Mg alloy plated steel having excellent plating adhesion and corrosion resistance includes: sequentially forming a first Zn plating layer, a second Mg plating layer, and a third Zn plating layer on base steel by a physical vapor deposition (PVD) method to provide a plated steel material; heating the plated steel material for alloying heat treatment to provide an alloy plated steel material; and cooling the alloy plated steel material, wherein in the providing of the plated steel material, the second Mg plating layer has a thickness of 30% to 35% of the sum of thicknesses of the first Zn plating layer, the second Mg plating layer, and the third Zn plating layer, and the first Zn plating layer has a thickness of 1.1 to 4 times a thickness of the third Zn plating layer. In the step of providing the plated steel material, the first Zn plating layer, the second Mg plating layer, and the third Zn plating layer may be formed to have a total thickness of 2 μm to 10 μm. The providing of the plated steel material may include: a first intermediate cooling operation of cooling the first Zn plating layer to room temperature after forming the first Zn plating layer; a second intermediate cooling operation