Tailored blank for hot stamping, hot stamped member, and methods for manufacturing same

Patent metadata

Field	Value
Publication number	US-9901969-B2
Application number	US-201314385559-A
Country	US
Kind code	B2
Filing date	Mar 28, 2013
Priority date	Mar 28, 2012
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A tailored blank for hot stamping includes a welded portion formed by butt-welding a first aluminum-plated steel sheet and a second aluminum-plated steel sheet, an Average Al concentration of a weld metal in the welded portion is in a range of 0.3 mass % to 1.5 mass %, an Ac 3 point of the weld metal is 1250° C. or lower, and furthermore, an aluminum layer formed during the butt-welding is present on a surface of the welded portion.

First claim

The invention claimed is:

1. A tailored blank for hot stamping comprising:
a welded portion formed by butt-welding a first aluminum-plated steel sheet and a second aluminum-plated steel sheet,
wherein an average Al concentration of a weld metal in the welded portion is 0.3 mass % to 1.5 mass %, in the following formula (1), an Ac 3 point of the weld metal defined in unit ° C. is 1250° C. or lower, and
an aluminum layer formed during the butt-welding is present on a surface of the welded portion,
Ac 3 =910−230×C 0.5 −15.2×Ni+44.7×Si+104×V+31.5×Mo+13.1×W−30×Mn−11×Cr−20×Cu+700×P+400×Al+120×As+400×Ti  Formula (1)

where, C, Ni, Si, V, Mo, W, Mn, Cr, Cu, P, Al, As, and Ti in Formula (1) represent amounts of individual elements in the weld metal in mass %, and elements not contained are considered to have an amount of zero in computation.

2. The tailored blank for hot stamping according to claim 1 ,
wherein, in the following formula (2), Δt M defined in unit of second is 0.5 seconds or longer,

Δ
⁢

⁢

t
M

=

exp
⁢

{

10.6
⁢

(

C
+

Si
+

5
×
Al

24

+

Mn
6

+

Cu
15

+

Ni
12

+

Mo
6

+

Cr
×

(

1
-

0.16
×

Cr

)

8

+

Δ
⁢

⁢
H

)

-
4.8

}

Formula
⁢

⁢

(
2
)

where, C, Si, Al, Mn, Cu, Ni, Mo, and Cr in Formula (2) represent amounts of individual elements in the weld metal in mass %, elements not contained are considered to have an amount of zero in computation, and ΔH represents a numeric value defined as described below in accordance with the amount of B in mass % and fN when the fN is set to (0.02−N)/0.02 using the amount of N in the weld metal in mass %,
when B≦0.0001, ΔH=0,
when 0.0001<B≦0.0002, ΔH=0.03×fN,
when 0.0002<B≦0.0003, ΔH=0.06×fN, and
when 0.0003<B, ΔH=0.09×fN.

3. The tailored blank for hot stamping according to claim 2 ,
wherein, an Ac 1 point of the weld metal defined in unit ° C. in the following formula (3) is 860° C. or lower,

Ac
1

=

exp
⁡

(

6.5792
-

0.038058
×
C

+

0.052317
×
Si

+

0.011872
×
Ni

-

0.045575
×
V

+

0.18057
×
Al

+

0.011442
×
W

-

0.013403
×
Cu

+

5.5207
×
B

+

0.91209
×
S

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Miyazaki Yasunobu
• Naito Yasuaki
• Kawasaki Kaoru
• Yoshinaga Takahiro

Classifications

• B23K10/02

  Plasma welding · CPC title

• B23K2103/50

  Inorganic materials other than metals or composite materials · CPC title

• B23K2101/32

  Wires · CPC title

• C22C38/32

  with boron · 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