Hot press formed article having excellent delamination resistance and method for manufacturing the same
First Claim
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1. A hot press formed (HPF) article having excellent delamination resistance, a hot dip aluminum plating layer being formed on a surface of a substrate steel sheet, wherein the substrate steel sheet includes, in % by weight, C:
- 0.18% to 0.25%, Si;
0.1% to 1.0%, Mn;
0.9% to 1.5%, P;
0.03% or less, S;
0.01% or less, Al;
0.01% to 0.05%, Cr;
0.05% to 0.5%, Ti;
0.01% to 0.05%, B;
0.001% to 0.005, N;
0.009% or less, and a remainder of Fe and other impurities;
the plating layer is formed to have a soft diffusion layer and a hard alloy layer;
the alloy layer comprises Fe2Al5 matrix phase and a tau phase comprised of Fe—
Al—
Si based alloy phase;
the tau phase is irregularly and discontinuously dispersed and distributed inside the alloy layer in an amount of 10% or greater based on the total area fraction so that a difference in hardnesses between the alloy layer and the diffusion layer is 400 (Hv) or less.
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Abstract
An HPF molding member having a melted aluminum plating layer formed on the surface of a base steel sheet and excellent delamination resistance. The base steel sheet comprises: 0.18-0.25% by weight of C; 0.1-1.0% by weight of Si; 0.9-1.5% by weight of Mn; 0.03% by weight or less of P; 0.01% by weight or less of S; 0.01-0.05% by weight of Al; 0.05-0.5% by weight of Cr; 0.01-0.05% by weight of Ti; 0.001-0.005% by weight of B; 0.009% by weight or less of N; and the balance Fe and other impurities. The plating layer consists of a soft diffusion layer and a hard alloy layer, the hard alloy layer having a tau layer irregularly and non-continuously dispersed and distributed on the inside thereof at 10% or more of the entire area fraction. The difference in hardness between the alloy layer and the diffusion layer is 400 (Hv) or less.
10 Citations
19 Claims
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1. A hot press formed (HPF) article having excellent delamination resistance, a hot dip aluminum plating layer being formed on a surface of a substrate steel sheet, wherein the substrate steel sheet includes, in % by weight, C:
- 0.18% to 0.25%, Si;
0.1% to 1.0%, Mn;
0.9% to 1.5%, P;
0.03% or less, S;
0.01% or less, Al;
0.01% to 0.05%, Cr;
0.05% to 0.5%, Ti;
0.01% to 0.05%, B;
0.001% to 0.005, N;
0.009% or less, and a remainder of Fe and other impurities;the plating layer is formed to have a soft diffusion layer and a hard alloy layer; the alloy layer comprises Fe2Al5 matrix phase and a tau phase comprised of Fe—
Al—
Si based alloy phase;the tau phase is irregularly and discontinuously dispersed and distributed inside the alloy layer in an amount of 10% or greater based on the total area fraction so that a difference in hardnesses between the alloy layer and the diffusion layer is 400 (Hv) or less. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- 0.18% to 0.25%, Si;
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10. A method for manufacturing a hot press formed (HPF) article having excellent delamination resistance, the method comprising:
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preparing a steel sheet including, in % by weight, C;
0.18% to 0.25%, Si;
0.1% to 1.0%, Mn;
0.9% to 1.5%, P;
0.03% or less, S;
0.01% or less, Al;
0.01% to 0.05%, Cr;
0.05% to 0.5%, Ti;
0.01% to 0.05%, B;
0.001% to 0.005, N;
0.009% or less, and a remainder of Fe and other impurities;hot dip aluminum plating the steel sheet by, after heating the steel sheet to a temperature of 550°
C. to 850°
C., immersing the steel sheet in a hot dip aluminum plating bath maintained at a temperature of 640°
C. to 680°
C. and composed of, in % by weight, Si;
7% to 13%, Fe;
less than 3%, and the remainder of Al and other unavoidable impurities;skin pass milling (SPM) the hot dip aluminum plating steel sheet with an elongation of 0.5% to 3% after cooling the hot dip galvanized steel sheet; alloying a hot dip aluminum plating layer on a surface of the hot dip aluminum plated steel sheet by heating the hot dip aluminum plated steel sheet to a temperature of 850°
C. to 950°
C. and maintaining the temperature for a certain period of time; andmanufacturing a hot press formed (HPF) product by rapidly cooling the alloyed hot dip aluminum plated steel sheet to a temperature of 300°
C. or lower while hot press forming the alloyed hot dip aluminum plated steel sheet. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification
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Current AssigneePOSCO Co. Ltd. (Posco Holdings Incorporated)
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Original AssigneePosco Holdings Incorporated
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InventorsKim, Heung-Yun, Sohn, Il-Ryoung, Bae, Dae-Chul
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Primary Examiner(s)Krupicka, Adam
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Application NumberUS15/250,022Publication NumberTime in Patent Office1,345 DaysField of SearchNoneUS Class CurrentCPC Class CodesB32B 15/012 one layer being formed of a...C21D 8/0226 Hot rollingC21D 8/0236 Cold rollingC21D 9/46 for sheet metalsC22C 21/02 with silicon as the next ma...C22C 38/001 containing NC22C 38/002 containing In, Mg, or other...C22C 38/02 containing siliconC22C 38/04 containing manganeseC22C 38/06 containing aluminiumC22C 38/28 with titanium or zirconiumC22C 38/32 with boronC22F 1/043 of alloys with silicon as t...C23C 2/022 by heatingC23C 2/12 Aluminium or alloys based t...C23C 2/28 Thermal after-treatment, e....C23C 2/285 for remelting the coatingC23C 2/29 Cooling or quenchingC23C 2/40 Plates; StripsC23C 30/00 Coating with metallic mater...
