Hot press formed article having good anti-delamination, and preparation method for same

• US 10,655,204 B2
• Filed: 04/05/2016
• Issued: 05/19/2020
• Est. Priority Date: 05/26/2015
• Status: Active Grant

• Current Assignee: POSCO Co. Ltd. (Posco Holdings Incorporated)
• Original Assignee: Posco Holdings Incorporated
• Inventors: Kim, Heung-Yun
• Primary Examiner(s): Schleis, Daniel J.
• Application Number:
  US15/576,525
• Publication Number:
  US 20180142337A1
• Time in Patent Office: 1,505 Days
• Field of Search: None
• CPC Class Codes: B21B 1/38 for rolling sheets of limited length, e.g. folded sheets, superimposed sheets, pack rollingB21B1/40 takes precedence; folding sheets before, or separating layers after, rolling B21B47/00
• CPC Class Codes: B32B 15/012 one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy
• CPC Class Codes: C21D 1/673 for die quenching
• CPC Class Codes: C21D 8/0205 of ferrous alloys
• CPC Class Codes: C21D 8/0273 Final recrystallisation annealing
• CPC Class Codes: C21D 9/46 for sheet metals
• CPC Class Codes: C22C 38/001 containing N
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/28 with titanium or zirconium
• CPC Class Codes: C22C 38/32 with boron
• CPC Class Codes: C22C 38/38 with more than 1.5% by weight of manganese
• CPC Class Codes: C23C 10/22 Metal melt containing the element to be diffused
• CPC Class Codes: C23C 2/12 Aluminium or alloys based thereon
• CPC Class Codes: C23C 2/20 Strips; Plates
• CPC Class Codes: C23C 2/28 Thermal after-treatment, e.g. treatment in oil bath
• CPC Class Codes: C23C 2/29 Cooling or quenching
• CPC Class Codes: Y10T 428/12757 Fe

Abstract

Provided is a hot press formed article having good anti-delamination and having a hot dip aluminized layer formed on the surface of a base steel sheet. The base steel sheet comprises 0.18-0.25 wt % of C, 0.1-0.5 wt % of Si, 0.9-1.5 wt % of Mn, 0.03 wt % or less of P, 0.01 wt % or less of S, 0.01-0.05 wt % of Al, 0.05-0.5 wt % of Cr, 0.01-0.05 wt % of Ti, 0.001-0.005 wt % of B, 0.009 wt % or less of N and the balance of Fe and other impurities. The aluminized layer comprises a single soft diffusion layer comprising α-Fe with solid-solubilized Al, and the hardness of the diffusion layer is 300-600 (Hv).

Claims

1. A hot press formed (HPF) article having an improved delamination resistance, the HPF article comprising:

a base steel sheet comprising;

carbon (C);

0.18 wt % to 0.25 wt %, silicon (Si);

0.1 wt % to 0.5 wt %, manganese (Mn);

0.9 wt % to 1.5 wt %, phosphorous (P);

0.03 wt % or less, sulfur (S);

0.01 wt % or less, aluminum (Al);

0.01 wt % to 0.05 wt %, chromium (Cr);

0.05 wt % to 0.5 wt %, titanium (Ti);

0.01 wt % to 0.05 wt %, boron (B);

0.001 wt % to 0.005 wt %, nitrogen (N);

0.009 wt % or less, a balance of iron (Fe) and other impurities; and

an aluminum plated layer formed on a surface of the base steel sheet,

wherein the aluminum plated layer comprises;

only a single soft diffusion layer comprising α

-Fe and aluminum (Al) solid-solubilized in the α

-Fe; and

the single soft diffusion layer has a hardness of 300 (Hv) to 600 (Hv).

2. The hot press formed article of claim 1, wherein the single soft diffusion layer has a thickness within a range of 2 μ

m to 40 μ

m.

3. The hot press formed article of claim 2, wherein the thickness is within a range of 2 μ

m to 10 μ

m.

4. The hot press formed article of claim 1, wherein the single diffusion layer includes 1.0 wt % to 5.0 wt % of at least one of silicon (Si), manganese (Mn) and aluminum (Al) based on the single diffusion layer.

5. The hot press formed article of claim 1, wherein the single diffusion layer includes 0.2 wt % to 1.0 wt % of at least one of chromium (Cr), molybdenum (Mo) and titanium (Ti) based on the single diffusion layer.