Al-plated steel sheet used for hot pressing and method for manufacturing Al-plated steel sheet used for hot pressing

Patent metadata

Field	Value
Publication number	US-9970116-B2
Application number	US-201415103152-A
Country	US
Kind code	B2
Filing date	Dec 10, 2014
Priority date	Dec 12, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

Provided is an Al-plated steel sheet used for hot pressing that has excellent lubricity in hot state, corrosion resistance after paint coating, and spot weldability. An Al-plated steel sheet used for hot pressing includes: a steel sheet; an Al plating layer formed on one surface or both surfaces of the steel sheet; and a surface coating layer formed on the Al plating layer. The surface coating layer contains a zinc compound, and the zinc compound is deposited on the Al-plated steel sheet in an amount of equal to or greater than 0.3 g/m 2 and equal to or less than 1.5 g/m 2 as an amount of metallic zinc per one surface, and a zinc deposition amount in any continuous 1 mm 2 region is 1.5 g/m 2 or less.

First claim

The invention claimed is:

1. An Al-plated steel sheet used for hot pressing, comprising:
a steel sheet;
an Al plating layer formed on one surface or both surfaces of the steel sheet; and
a surface coating layer formed on the Al plating layer,
wherein the surface coating layer contains a zinc compound, and the zinc compound is deposited on the Al-plated steel sheet in an amount of equal to or greater than 0.3 g/m 2 and equal to or less than 1.5 g/m 2 as an amount of metallic zinc per one surface, and a zinc deposition amount in any continuous 1 mm 2 region is 1.5 g/m 2 or less.

2. The Al-plated steel sheet used for hot pressing according to claim 1 ,
wherein the zinc compound in the surface coating layer is zinc oxide.

3. The Al-plated steel sheet used for hot pressing according to claim 1 ,
wherein an average length RSm of a profile element in a roughness curve of a surface of the Al-plated steel sheet used for hot pressing after the formation of the surface coating layer is 500 μm or less.

4. The Al-plated steel sheet used for hot pressing according to claim 2 ,
wherein an average length RSm of a profile element in a roughness curve of a surface of the Al-plated steel sheet used for hot pressing after the formation of the surface coating layer is 500 μm or less.

5. A method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 1 ,
said method comprising the steps of:
applying an application liquid containing a zinc compound and having a contact angle of equal to or greater than 20° and equal to or less than 50° with respect to the Al-plated steel sheet onto the Al-plated steel sheet including a steel sheet and the Al plating layer formed on one surface or both surfaces of the steel sheet; and
drying the Al-plated steel sheet onto which the application liquid has been applied, at a peak metal temperature of equal to or higher than 60° C. and equal to or lower than 200° C., to form a surface coating layer containing the zinc compound on the Al plating layer.

6. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 5 ,
wherein a surface tension of the application liquid at 25° C. is equal to or greater than 20 mN/m and equal to or less than 60 mN/m.

7. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 5 ,
wherein a viscosity of the application liquid at 25° C. is equal to or greater than 2 mPa·s and equal to or less than 20 mPa·s.

8. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 6 ,
wherein a viscosity of the application liquid at 25° C. is equal to or greater than 2 mPa·s and equal to or less than 20 mPa·s.

9. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 5 ,
wherein the application liquid is applied onto the Al plating layer with a roll coater.

10. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 5 ,
wherein the zinc compound is zinc oxide.

11. The method for manufacturing the Al-plated steel sheet used for hot pressing according to claim 5 ,
wherein an average length RSm of a profile element in a roughness curve of a surface of the manufactured Al-plated steel sheet used for hot pressing after the formation of the surface coating layer is 500 μm or less.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Fujita Soshi
• Yamanaka Shintaro
• Maki Jun
• Fujimoto Hiroki
• Oikawa Hatsuhiko
• Irikawa Hideaki

Classifications

• C22C21/02

  with silicon as the next major constituent · 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

• Y10T428/12757

  Fe · CPC title

• B21D35/005

  characterized by the material of the blank or the workpiece (B21D26/053 takes precedence) · CPC title

• C23C2/12 Primary

  Aluminium or alloys based thereon · CPC title