Hot-dip Al—Zn coated steel sheet

Patent metadata

Field	Value
Publication number	US-9234267-B2
Application number	US-201113989515-A
Country	US
Kind code	B2
Filing date	Nov 25, 2011
Priority date	Nov 26, 2010
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

There is provided a hot-dip Al—Zn coated steel sheet that has a steel sheet containing Si and Mn as a base steel sheet and has excellent coating appearance and corrosion resistance. The Al—Zn coating layer has an Al content in the range of 20% to 95% by mass. The Al—Zn coating layer has a Ca content in the range of 0.01% to 10% by mass. Alternatively, the Ca and Mg content is in the range of 0.01% to 10% by mass. A steel sheet surface layer within 100 μm from a surface of the base steel sheet directly under the Al—Zn coating layer contains less than 0.060 g/m 2 per surface of an oxide of at least one selected from Fe, Si, Mn, Al, P, B, Nb, Ti, Cr, Mo, Cu, and Ni in total.

First claim

The invention claimed is:

1. A hot-dip Al—Zn coated steel sheet that includes an Al—Zn coating layer having an Al content in the range of 20% to 95% by mass on a surface of the steel sheet, wherein the Al—Zn coating layer contains 0.01% to 10% by mass of Ca, the coating layer having equal parts in a thickness direction with one part nearer an outer surface of the coating layer and one part nearer the steel sheet, wherein the Ca is present in a greater amount in the part of the coating layer nearer the outer surface of the coating layer, and wherein a steel sheet surface layer within 100 μm from a surface of the base steel sheet directly under the Al—Zn coating layer contains less than 0.060 g/m 2 per surface of an oxide of at least one selected from Fe, Si, Mn, Al, P, B, Nb, Ti, Cr, Mo, Cu, and Ni in total.

2. The hot-dip Al—Zn coated steel sheet according to claim 1 , wherein the ratio Ca/Zn of the Ca content to the Zn content in the Al—Zn coating layer is 0.50 or less.

3. The hot-dip Al—Zn coated steel sheet according to claim 1 , wherein the Al—Zn coating layer contains more than 2.00% by mass and 10% by mass or less of Ca or Ca and Mg in total.

4. A hot-dip Al—Zn coated steel sheet that includes an Al—Zn coating layer having an Al content in the range of 20% to 95% by mass on a surface of the steel sheet, wherein the Al—Zn coating layer contains 0.01% to 10% by mass of Ca and Mg in total, wherein the mass of Ca is greater than zero and the mass of Mg is greater than zero, the coating layer having equal parts in a thickness direction with one part nearer an outer surface of the coating layer and one part nearer the steel sheet, wherein the Ca and Mg are present in a greater amount in the part of the coating layer nearer the outer surface of the coating layer, and wherein a steel sheet surface layer within 100 μm from a surface of the base steel sheet directly under the Al—Zn coating layer contains less than 0.060 g/m 2 per surface of an oxide of at least one selected from Fe, Si, Mn, Al, P, B, Nb, Ti, Cr, Mo, Cu, and Ni in total.

Assignees

• Yoshida Masahiro
• Nakamaru Hiroki
• Jfe Steel Corp

Inventors

• Yoshida Masahiro
• Nakamaru Hiroki

Classifications

• Y10T428/12611

  Oxide-containing component · CPC title

• Y10T428/27

  Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] · CPC title

• Y10T428/12736

  Al-base component · CPC title

• Y10T428/12667

  Oxide of transition metal or Al · CPC title

• Y10T428/12979

  Containing more than 10% nonferrous elements [e.g., high alloy, stainless] · CPC title