# US 2020/0399745 A1 · Single layer zinc alloy plated steel material exhibiting excellent spot weldability and corrosion resistance, and fabrication method therefor

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- Number: US 2020/0399745 A1
- Document ID: US20200399745A1
- Status: Published application
- Kind: A1
- Application number: 16/472,475
- Filed: 2017-12-21
- Published: 2020-12-24
- Earliest claimed: 2016-12-26
- Assignees: Posco
- Applicants: Posco
- Inventors: Young-Jin KWAK; Tae-Yeob KIM
- Web page: https://patentgrep.com/patent/US20200399745A1

## CPC

- C22C 38/06: containing aluminium
- C23C 14/16: on metallic substrates or on substrates of boron or silicon
- B23K 26/22: Spot welding
- B23K 35/3073: {with Mn as next major constituent}
- C22C 18/00: Alloys based on zinc
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C23C 2/06: Zinc or cadmium or alloys based thereon
- C23C 14/021: {Cleaning or etching treatments}
- C23C 14/14: Metallic material, boron or silicon
- C23C 14/28: by wave energy or particle radiation (C23C14/32 - C23C14/48 take precedence)
- C23C 14/50: Substrate holders
- C23C 28/023: {only coatings of metal elements only}
- C23C 28/025: {with at least one zinc-based layer}
- C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence)
- B23K 2103/04: Steel {or steel} alloys
- C21D 2211/001: Austenite
- Y10T 428/12799: Next to Fe-base component [e.g., galvanized]
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Provided are a single layer zinc alloy plated steel material and a fabrication method therefor, the single layer zinc alloy plated steel material comprising a base iron and a zinc alloy plating layer formed on the base iron, wherein the zinc alloy plating layer contains 13-24 wt % of Mg, and the adhesion amount of the zinc alloy plating layer is at most 40 g/m2 (excluding 0 g/m2).

## Claims

### Claim 1

A single layer zinc alloy plated steel comprising:
a base steel and a zinc alloy plating layer disposed on the base steel,
wherein the zinc alloy plating layer includes 13 to 24 wt % of magnesium (Mg), and a plating amount of the zinc alloy plating layer is 40 g/m2 or less (excluding 0 g/m2).

### Claim 2 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein the zinc alloy plating layer comprises 15.7 to 20 wt % of Mg.

### Claim 3 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein the plating amount of the zinc alloy plating layer is 10 to 35 g/m2.

### Claim 4 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein an average grain size of crystal grains constituting the zinc alloy plating layer is 100 nm or less (excluding 0 nm).

### Claim 5 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein, when a GDS profile on a central portion of the zinc alloy plating layer in a thickness direction is measured, a deviation of Mg content is within ±5%.

### Claim 6 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein during spot welding of the single layer zinc alloy plated steel material, a zinc alloy plating layer on a welded portion is changed to an alloy layer comprising 90% or more by area (including 100% by area) of MgZn2 alloy phase.

### Claim 7 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein an average length of Type B cracks in the single layer zinc alloy plated steel is 0.1 time or less a base steel thickness when spot welding is performed according to SEP 1220-2 standard.

### Claim 8 (depends on 1)

The single layer zinc alloy plated steel of claim 1, wherein the base steel comprises, by weight %, 0.10 to 1.0% of carbon (C), 0.5 to 3% of silicon (Si), 1.0 to 25% of manganese (Mn), 0.01 to 10% of aluminum (Al), 0.1% or less (excluding 0%) of phosphorus (P), 0.01% or less (excluding 0%) of sulfur (S), and remainders of iron (Fe) and unavoidable impurities.

### Claim 9 (depends on 8)

The single layer zinc alloy plated steel of claim 8, wherein the contents of C, Si, Mn, P and S contained in the base steel satisfy the following relational expression 1: [C]+[Mn]/20+[Si]/30+2[P]+4[S]≥0.3, where [C], [Mn], [Si], [P] and [S] are the contents (weight %) of respective elements.

### Claim 10 (depends on 8)

The single layer zinc alloy plated steel of claim 8, wherein the base steel comprises one or more of austenite and retained austenite as a microstructure.

### Claim 11

A method of manufacturing a single layer zinc alloy plated steel material, comprising:
preparing a base steel; and
levitating and heating a coating material by electromagnetic force in a vacuum chamber to generate zinc (Zn) and magnesium (Mg) alloy deposition vapor, and inducing and spraying the Zn and Mg alloy deposition vapor onto a surface of the base steel to form a Mg deposition layer,
wherein a content of Mg in the Zn and Mg alloy deposition vapor is 13 to 24 wt %, and a plating amount of a zinc alloy plating layer is 40 g/m2 or less (excluding 0 g/m2).

### Claim 12 (depends on 11)

The method of claim 11, wherein the content of Mg in the Zn and Mg alloy deposition vapor is 15.7 to 20 wt %.

### Claim 13 (depends on 11)

The method of claim 11, wherein the coating material levitated in the levitating and heating of a coating material has a temperature of 700° C. or higher.

### Claim 14 (depends on 11)

The method of claim 11, wherein the base steel has a temperature of 100° C. or lower before and after deposition.