High Mn steel sheet for high corrosion resistance and method of manufacturing galvanizing the steel sheet

Patent metadata

Field	Value
Publication number	US-9580786-B2
Application number	US-9754306-A
Country	US
Kind code	B2
Filing date	Dec 20, 2006
Priority date	Dec 24, 2005
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A high-manganese hot-dip coated steel sheet is disclosed which provides high corrosion resistance, high ductility and high strength, mainly used for inner and outer panels of automobiles, and a method of manufacturing the same. The high-manganese hot-dip coated steel sheet includes a substrate steel sheet having a composition of (in weight %) 0.1 to 1.5% of C, 5 to 35% of Mn, and the remainder includes Fe and other unavoidable impurities, and a hot-dip zinc coating layer formed on the substrate steel sheet, the hot-dip zinc coating layer having a composition of (in weight %) 0.1 to 10% of Mn, 5 to 15% of Fe, and the remainder including Zn and other unavoidable impurities.

First claim

The invention claimed is:

1. A high-manganese hot-dip coated steel sheet exhibiting superior corrosion resistance, comprising:
a substrate steel sheet having a composition of (in weight %) 0.1 to 1.5% of C, 15.18% to 35% of Mn, 0.01 to 3% of Al, and the remainder including Fe and other unavoidable impurities, wherein the substrate steel sheet further contains one or more elements selected from a group consisting of less than 3% but more than 0% of Si, less than 9% but more than 0% of Cr, less than 5% but more than 0% of Cu, less than 4% but more than 0% of Ni, less than 1% but more than 0% of Mo, less than 1% but more than 0% of Nb, less than 0.5% but more than 0% of V, and less than 0.04% but more than 0% of N, wherein the substrate steel sheet has austenite as a main phase; and
an alloying hot-dip coating layer formed on the substrate steel sheet, the alloying hot-dip coating layer having a composition of (in weight %) 0.1 to 10% of Mn, 5 to 15% of Fe, and the remainder including Zn and other unavoidable impurities,
wherein the alloying hot-dip coating layer consists of a single layer structure that consists of δ phase, and wherein the alloying hot-dip coating layer is formed during an alloy heat-treatment after deposition of a hot-dip zinc coating layer, whereby the Mn content of the substrate steel sheet acts as a Mn source for the coating layer during the alloying heat-treatment.

2. The steel sheet according to claim 1 , wherein the substrate steel sheet further contains one or more elements selected from a group consisting of 0.005 to 0.05% of Sn, 0.005 to 0.05% of Sb, 0.005 to 0.05% of As, and 0.005 to 0.05% of Te.

3. The steel sheet according to claim 1 , wherein the substrate steel sheet further contains one or more elements selected from a group consisting of 0.0005 to 0.040% of B, 0.0005 to 0.1% of Zr, 0.0005 to 0.1% of Ti, 0.0005 to 0.040% of La, 0.0005 to 0.040% of Ce, and 0.0005 to 0.030% of Ca.

4. The steel sheet according to claim 2 , wherein the substrate steel sheet further contains one or more elements selected from a group consisting of 0.0005 to 0.040% of B, 0.0005 to 0.1% of Zr, 0.0005 to 0.1% of Ti, 0.0005 to 0.040% of La, 0.0005 to 0.040% of Ce, and 0.0005 to 0.030% of Ca.

Assignees

• Sohn Il-Ryoung
• Chin Kwang-Geun
• Kim Seong-Ju
• Kim Myung-Soo
• Kim Sung-Kyu
• Posco

Inventors

• Sohn Il-Ryoung
• Chin Kwang-Geun
• Kim Seong-Ju
• Kim Myung-Soo
• Kim Sung-Kyu

Classifications

• Y10T428/12799

  Next to Fe-base component [e.g., galvanized] · CPC title

• B32B15/012

  one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy · CPC title

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• C21D6/005

  containing Mn · CPC title

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title