# US 9,040,168 B2 · Galvannealed steel sheet having excellent formability and exfoliation resistance after adhesion and production method thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,040,168 B2
- Document ID: US9040168B2
- Status: Granted
- Kind: B2
- Application number: 13/504,068
- Filed: 2010-07-12
- Published: 2012-08-23
- Granted: 2015-05-26
- Earliest claimed: 2009-10-26
- Assignees: Nippon Steel & Sumitomo Metal Corporation
- Applicants: Kazuhiko Honda; Noriyuki Suzuki; Yoichi Ikematsu
- Inventors: Kazuhiko Honda; Noriyuki Suzuki; Yoichi Ikematsu
- Web page: https://patentgrep.com/patent/US9040168B2

## CPC

- C23C 28/321: {with at least one metal alloy layer}
- B32B 15/013: {one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium}
- C22C 18/00: Alloys based on zinc
- C22C 38/001: {containing N}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C22C 38/14: containing titanium or zirconium
- C23C 2/04: characterised by the coating material
- C23C 2/06: Zinc or cadmium or alloys based thereon
- C23C 2/26: After-treatment (C23C2/14 takes precedence)
- C23C 2/28: Thermal after-treatment, e.g. treatment in oil bath
- C23C 22/18: containing manganese cations
- C23C 22/73: characterised by the process
- C23C 28/345: {with at least one oxide layer}
- Y10T 428/12799: Next to Fe-base component [e.g., galvanized]
- 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)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The galvannealed steel sheet includes: a galvannealed layer formed on at least one surface of a steel sheet and contains includes an amount of 0.05 mass % to 0.5 mass % of Al, an amount of 6 mass % of 12 mass % of Fe, and the balance composed of Zn and inevitable impurities; and a mixed layer formed on a surface of the galvannealed layer and includes a composite oxide of Mn, Zn, and P and an aqueous P compound, wherein the composite oxide includes 0.1 mg/m2 to 100 mg/m2 of Mn, an amount of 1 mg/m2 to 100 mg/m2 of P, and Zn, and a P/Mn ratio is 0.3 to 50, and wherein the total size of an area of the mixed layer in which an attached amount of P is equal to or more than 20 mg/m2 is 20% to 80% of a surface area of the mixed layer.

## Claims

### Claim 1

A galvannealed steel sheet comprising:
a steel sheet;
a galvannealed layer which is formed on at least one surface of the steel sheet and includes an amount equal to or more than 0.05 mass % and equal to or less than 0.5 mass % of Al, an amount equal to or more than 6 mass % and equal to or less than 12 mass % of Fe, and optionally a total amount equal to or less than 2 mass % of at least one of Pb, Sb, Si, Fe, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi, and rare earth elements, and the balance composed of Zn and inevitable impurities; and
a mixed layer which is formed on a surface of the galvannealed layer and includes a composite oxide of Mn, Zn, and P and an aqueous P compound,
wherein the composite oxide includes an amount equal to or more than 0.1 mg/m2 and equal to or less than 100 mg/m2 of Mn, an amount equal to or more than 1 mg/m2 and equal to or less than 100 mg/m2 of P, and Zn, and has a P/Mn ratio of equal to or higher than 0.3 and equal to or lower than 50, and
wherein the mixed layer includes a first applied part and a second applied part, an attached amount of P in the second applied part being larger than an attached amount of P in the first applied part, the attached amount of P in the second applied part being equal to or more than 20 mg/m2, and
a total surface area of the second applied part is equal to or higher than 20% and equal to or lower than 80% of a surface area of the mixed layer;
wherein the total size of an area of the mixed layer in which the P/Mn ratio is equal to or higher than 3 is equal to or higher than 1% and equal to or lower than 50% of the surface area of the mixed layer.

### Claim 2 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the mixed layer includes at least one kind of phosphoric acid group, phosphorous acid group, and hypophosphorous acid group.

### Claim 3 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein a ratio of the aqueous P compound in the mixed layer is equal to or more than 1 mass % and equal to or less than 50 mass %.

### Claim 4 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein, when:
an X-ray diffraction intensity of d=3.13 of an Si standard sheet is defined to be ISi;
an X-ray diffraction intensity of d=1.237 of the galvannealed layer is defined to be Iη;
an X-ray diffraction intensity of d=1.26 of the galvannealed layer is defined to be Iζ; and
an X-ray diffraction intensity of d=1.222 of the galvannealed layer is defined to be IΓ,
Iη/ISi<0.0006,
Iζ/ISi>0.0005, and
IΓ/ISi<0.004,
are satisfied.

### Claim 5 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the steel sheet contains by mass:
an amount equal to or more than 0.0001 to 0.004% of C;
an amount equal to or more than 0.001 and equal to or less than 0.15% of Si;
an amount equal to or more than 0.01 and equal to or less than 1% of Mn;
an amount equal to or more than 0.001 and equal to or less than 0.1% of P;
an amount equal to or less than 0.015% of S;
an amount equal to or more than 0.001 and equal to or less than 0.1% of Al;
an amount equal to or more than 0.002 and equal to or less than 0.10% of Ti;
an amount equal to or more than 0.0005 and equal to or less than 0.0045% of N; and
the balance composed of Fe and inevitable impurities.

### Claim 6 (depends on 5)

The galvannealed steel sheet according to claim 5, wherein the steel sheet further contains an amount equal to or more than 0.002% and equal to or less than 0.10% of Nb by mass.

### Claim 7 (depends on 5)

The galvannealed steel sheet according to claim 5, wherein the steel sheet further contains an amount equal to or more than 0.0001% and equal to or less than 0.003% of B by mass.

### Claim 8 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the steel sheet contains by mass:
an amount more than 0.004% and equal to or less than 0.3% of C;
an amount equal to or more than 0.001% and equal to or less than 2% of Si;
an amount equal to or more than 0.01% and equal to or less than 4.0% of Mn;
an amount equal to or more than 0.001% and equal to or less than 0.15% of P;
an amount equal to or less than 0.015% of S;
an amount equal to or less than 2% of Al;
an amount equal to or more than 0.0005% and equal to or less than 0.004% of N; and
the balance composed of Fe and inevitable impurities.

### Claim 9 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein a thickness of the mixed layer is equal to or greater than 0.1 nm and smaller than 10 nm.

### Claim 10 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the composite oxide of Mn, Zn, and P mainly contains an amorphous compound.

### Claim 11 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the application concentration distribution formed on the mixed layer by the first applied part and the second applied part has a stripe shape.

### Claim 12 (depends on 1)

The galvannealed steel sheet according to claim 1, wherein the application concentration distribution formed on the mixed layer by the first applied part and the second applied part has a stripe shape, the stripe shape being either perpendicular or parallel to a transport direction of the steel sheet.