US 2026/0102854 A1Published application

Laser welding method and laser weld joint

AssigneeJfe Steel Corporation

InventorsAtsushi TAKADA, Takatoshi OKABE

Life of this patent

Estimating the term…

Loading patent…

Abstract

A laser welding method for preventing cracking and obtaining a weld joint of a weld metal with excellent toughness, and a laser weld joint. The laser welding method includes butting steel material members, the steel material having a chemical composition including, in mass %, C: 0.04 to 0.15%, Si: 0.05 to 1.00%, Mn: 0.50 to 2.50%, P: 0.030% or less, S: 0.020% or less, Al: 0.050% or less, Ti: 0.050% or less, O: 0.010% or less, and N: 0.008% or less, and having a carbon equivalent Ceq, represented by the following Expression (1), of 0.30 to 0.45, with the balance being Fe and unavoidable impurities, covering a portion on the surfaces of the steel material members including a weld line with flux having a predetermined composition, and performing laser welding thereon to produce a weld joint. Ceq=[C]+[Mn]/6+[Si]/24+[Cu]/20+[Ni]/40+[Cr]/5+[Mo]/4 (1)

Claims12

Dependent claims

A laser welding method for joining members of a steel material comprising butting the members of a steel material, using flux to cover a portion of a resulting steel material surface that includes a weld line, and emitting a laser beam from above,

characterized in that
the steel material has a chemical composition including, in mass %:
C:
0.04 to 0.15%,
Si:
0.05 to 1.00%,
Mn:
0.50 to 2.50%,
P:
0.030% or less,
S:
0.020% or less,
Al:
0.050% or less,
Ti:
0.050% or less,
O:
0.010% or less, and
N:
0.008% or less, and
also optionally including at least one element selected from the group consisting of:
Cu:
1.00% or less,
Ni:
2.00% or less,
Cr:
1.00% or less,
Mo:
1.00% or less,
Nb:
0.20% or less,
V:
0.20% or less,
Ca:
0.005% or less,
REM:
0.050% or less, and
B:
0.0030% or less,
with a balance being Fe and unavoidable impurities,
a carbon equivalent Ceq of the steel material represented by the following Expression (1) is in the range of 0.30 to 0.45,
a component index X of the flux represented by the following Expression (2) is in the range of 0.5 to 2.5,
α represented by the following Expression (3) is in the range of 0.2 to 1.1, and
β represented by the following Expression (4) is in the range of 0.2 to 2.5:
Ceq
=
[
C
]
+
[
Mn
]
/
6
+
[
Si
]
/
24
+
[
Cu
]
/
20
+
[
Ni
]
/
40
+
[
Cr
]
/
5
+
[
Mo
]
/
4
(
1
)
X
=
{
(
CaO
)
+
(
MgO
)
+
(
CaF
2
)
+
0.5
(
MnO
)
+
(
B
2
⁢
O
3
)
}
/
⁢
{
(
SiO
2
)
+
0.5
(
Al
2
⁢
O
3
)
+
0.5
(
TiO
2
)
}
(
2
)
α
=
[
Al
]
/
(
0.025
+
0.05
×
log
0.1
⁢
X
)
(
3
)
β
=
{
[
Ti
]
+
(
TiO
2
)
/
2000
}
/
(
0.025
+
0.05
×
log
0.1
⁢
X
)
,
(
4
)
where each [element] in each expression represents a content (mass %) of the element in the steel material, each (component) in each expression represents a content (mass %) of the component in the flux, and if the element or the component is not contained, a value of the content (mass %) is 0.

189 more elements

Dependencies are inferred from the claim text.