The present invention relates to a welded structure member and a
manufacturing method thereof
Priority is claimed on Japanese Patent Application No. 2014-204583, filed on
October 3, 2014, and Japanese Patent Application No. 2015-158817, filed on August
Il, 201 .J., the contents of which arc mc,orporatcd hereii1 by reference .
[Related Art]
[0002]
Recently, in order to improve a fuel efficiency of a vehicle, weight saving of a
vehicle body has progressed. Then, in order to realize the weight saving of the
vehicle body, a welded structure member in which high-strength steel sheets are
welded to each other is used as a vehicle body material.
[0003]
The welded structure member which is used as the vehicle body material is
required to have an excellent fatigue strength. However, in the related art, it is known
that even in a case of using the high-strength steel sheet, it is difficult to sufficiently
improve the fatigue strength of the welded structure member. Therefore, for example,
in Patent Document I, a technology for improving the fatigue strength of the welded
structure member is proposed.
[0004]
A fillet arc welded joint described in Patent Document I includes a bead for
- I -
reinforcement separately from a fillet bead which is formed at the time of performing
fillet arc welding with respect to metal members. The bead for reinforcement is
formed on the same plane as that of the fillet bead by using the fillet bead as a starting
point. By the bead for reinforcement, it is possible to improve a fatigue strength of
the welded joint.
[Prior Art Document]
[Patent Document]
[0005]
[Patent Document 1] PCT International Publication No. W02013/157557
[Disclosure of the Invention]"
[Problems to be Solved by the Invention]
[0006]
However, in a chassis section (a section supporting a suspension) of the
vehicle body, aT-shaped welded joint (hereinafter, also referred to as aT-joint) is used
as the welded structure member. The chassis section is a section supporting a vehicle
body load, and thus, in the T-joint which is used in the chassis section, in particular, it
is necessary to improve a fatigue strength.
[0007]
In Patent Document 1, the T-joint formed of a vertical steel sheet and a
horizontal steel sheet is also disclosed. In the T-joint of Patent Document I, the bead
for reinforcement is formed to intersect with the fillet bead joining the vertical steel
sheet to the horizontal steel sheet. In Patent Document I, it is described that the
defonnation of the T-jointis prevented, and fatigue life is improved, by forming the
bead for reinforcement as described above.
[0008]
- 2 -
-· ·,·,,, ..
However, in the technology of Patent Document 1, there is a case where a
restriction on the manufacturing increases according to the structure of the T-joint.
Hereinafter, the case will be specifically described.
[0009]
As described above, in the technology of Patent Document 1, the bead for
reinforcement has to be formed to intersect with the fillet bead. For this reason, when
the bead for reinforcement is formed, a welding torch has to be moved to intersect with
the fillet bead. At this time, in a case where the welding torch can be smoothly
moved between the vertical steel sheet and the horizontal steel sheet, it is possible to
·easily form a suitable bead.for reinforcement. However,' forecond surface and of penetrating lhrongh· thtf.hasernetal'melnber,·.in which
when a direction from an abutting end section which is an end section of the abutting
surface towards a direction in which the abutting surface exists is set to the rear, and
the opposite direction thereof is set to the front, the weld bead includes a weld bead
end section in a position which is separated to the front of the abutting end section.
[0013]
(2) In the welded structure member according to (I) described above, the
weld overlay section may be disposed over a position which is separated from the
abutting end section to the rear by 1.9 mm to 7.0 mm, in the view of facing the second
surface and of penetrating through the base metal member.
(3) In the welded structure member according to (2) described above, a front
end of the weld overlay section may be positioned from the abutting end section to the
front, and a rear end of the weld overlay section may be positioned from the abutting
end section to the rear, in the view of facing the second surface and of penetrating
through the base metal member.
(4) In the welded structure member according to (2) or (3) described above,
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. the weld overlay section may be parallel to the abutting surface, in the view of facing
the second surface and of penetrating through the base metal member.
(5) In the welded structure member according to any one of (2) to (4)
described above, a separation distance Lw (mm) between the abutting end section and
the weld bead end section, and a plate thickness T (mm) of the base metal member may
satiszy Expression (A) described below
-0.125Lw + 4.06 mm <:: T <:: 4.5 mm ... Expression (A)
(6) In the welded structure member according to any one of (2) to (5)
described above, a length of the weld overlay section may be greater than or equal to
10.0 mrn. -, • o' ; ~ .. ~.,,.
[OOI4]
(7) In the welded structure member according to ( 1) described above, the
weld overlay section may be disposed over a position which is separated from the weld
bead end section to the rear by 0.1 mm to 3.0 mm, in the view of facing the second
surface and of penetrating through the base metal member.
(8) In the welded structure member according to (7) described above, a front
end of the weld overlay section may be positioned from the weld bead end section to
the front, and a rear end of the weld overlay section may be positioned from the weld
bead end section to the rear, in the view of facing the second surface and of penetrating
through the base metal member.
(9) In the welded structure member according to (7) or (8) described above,
the weld overlay section may be parallel to the weld bead, in the view of facing the
second surface and of penetrating through the base metal member.
(I 0) In the welded structure member according to any one of (7) to (9)
described above, a separation distance Lw (mm) between the abutting end section and
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the weld bead end section, and a plate thickness T (mm) of the base metal member may
satisfy Expression (B) described below.
0.8 mm :<: T < -0.1 25Lw + 4.06 mm ... Expression (B)
(11) In the welded structure member according to any one of (7) to (10)
described above, a length of the weld overlay section may be greater than or equal to
6.0mm.
[00 15]
(12) In the welded structure member according to any one of(1) to (11)
described above, a height of the weld overlay section from the second surface may be
2.0 rnm to 20.0 rnn1.
(13) In the welded structure member according to any one of(1) to (12)
described above, the weld overlay section may be a weld overlay bead which is not
involved in the joint between the base metal member and the other member.
(14) In the welded structure member according to any one of(l) to (13)
described above, the weld overlay section may be formed to enter the base metal
member.
(15) In the welded structure member according to any one of (1) to (14)
described above, the weld bead may not penetrate through the base metal member.
(16) In the welded structure member according to any one of(1) to (15)
described above, the base metal member may be a steel sheet having a tensile strength
of greater than or equal to 270 MPa.
[0016]
( 17) According to a second aspect ofthe present invention, there is provided
a method of manufacturing the welded structure member according to any one of ( 1) to
( 16) described above, the method including: a weld bead applying step of applying a
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. ' ~ -.
weld bead which joins the first surface of the base metal member to the end surface of
the joined metal member by the abutting surface; and a weld overlay section applying
step of applying the weld overlay section onto the second surface of the base metal
member by arc welding or brazing, before the weld bead applying step or after the
weld bead applying step.
[Effects of the Invention]
[0017]
According to the present invention, it is possible to improve a fatigue strength
of the welded structure member by a simple configuration, that is, by forming the
· linear weld· overlay scctiot'1 on tiJC secund surface'(a rear surfuce) ofthe base metal
member. In this case, a restriction on the manufacturing decreases, and it is possible
to easily improve the fatigue strength of the welded structure member. Specifically,
for example, even in a case where a plate-like section of the joined metal member is
welded to a plate-like section of the base metal member by being greatly inclined, it is
not necessary to fonn the weld overlay section between both of the plate-like sections,
and thus, the restriction on the manufacturing docs not increase. Accordingly, it is
possible to easily manufacture the welded structure member of which the fatigue
strength is improved.
[Brief Description of the Drawings]
[0018]
FIG. 1 is a perspective view illustrating a welded structure member 1 OA
according to a first embodiment of the present invention.
FIG. 2 is a perspective view of the welded structure member 1 OA according to
the same embodiment seen from a lower side.
FIG. 3 is a side view illustrating a part of the welded structure member lOA
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',;
according to the same embodiment.
FIG. 4 is a projection view of an abutting surface, a weld bead, and a weld
overlay section of the welded structure member I OA according to the same
embodiment.
FIG. 5 is a projection view of an abutting surface, a weld bead, and a weld
overlay section of a welded structure member I OA' according to a modification
example of the first embodiment of the present invention.
FIG. 6 is a perspective view illustrating a welded structure member lOB
according to a second embodiment of the present invention.
FIG 7'is"a-perspecti'vo vil:w of the weldetl structure' member lOB•aceorcftng-io
the same embodiment seen from a lower side.
FIG. 8 is a side view illustrating a part of the welded structure member JOB
according to the same embodiment.
FIG. 9 is a projection view of an abutting surface, a weld bead, and a weld
overlay section of the welded structure member I OB according to the same
embodiment.
FIG. 1 OA is a graph illustrating a relationship between a front end position of
the weld overlay section with respect to an abutting end section and a maximum value
of a maximum main stress in the abutting end section at each length of the weld
overlay section, which is obtained by computer analysis.
FIG. I OB is a graph illustrating a relationship between a rear end position of
the weld overlay section with respect to the abutting end section and the maximum
value of the maximum main stress in the abutting end section at each length ofthe
weld overlay section, which is obtained by the computer analysis.
FIG. llA is a graph illustrating a relationship between the length ofthe weld
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overlay section and a lower limit of the front end position of the weld overlay section,
when a decrease rate ofthe maximum value of the maximum main stress in the
abutting end section is 30%.
FIG. liB is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the abutting end section is 50%.
FIG. llC is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the front end position of the weld overlay
section, ·when thc•tkcr~usc rate of lhe maximum value oftlieiriivdmumrnaill·slresS'in
the abutting end section is 75%.
FIG. liD is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit ofthe front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the abutting end section is 90%.
FIG. 12A is a graph illustrating a relationship between the length of the weld
overlay section and an upper limit of the front end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 30%.
FIG. 128 is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit ofthe front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the abutting end section is 50%.
FIG. 12C is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the front end position of the weld overlay
- 9 -
section, when the decrease rate of the maximum value of the maximum main stress in
the abutting end section is 75%.
FIG. 120 is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the abutting end section is 90%.
FIG. 13A is a graph .illustrating a relationship between thelength.ofthe weld
overlay section and a lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 30%.
FIG. 13B is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 50%.
FIG. 13C is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 75%.
FIG. !3D is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit ofthe rear end position of the weld overlay section,
when the decrease rate of the maximum value ofthe maximum main stress in the
abutting end section is 90%.
FIG. 14A is a graph illustrating a relationship between the length ofthe weld
overlay section and an upper limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
- 10 -
,.,,.,-
abutting end section is 30%.
FIG. 148 is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit ofthe rear end position of the weld overlay section,
when the decrease rate ofthe maximum value of the maximum main stress in the
abutting end section is 50%.
FIG. 14C is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 75%.
HG. J4Dis a graph illustrating a relationship betweetHh·elengtl1'\'ifthe weld
overlay section and the upper limit ofthe rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the
abutting end section is 90%.
FIG. !SA is a graph illustrating a relationship between the front end position
ofthe weld overlay section with respect to a weld bead end section and the maximum
value of the maximum main stress in the weld bead end section at each length of the
weld overlay section, which is obtained by the computer analysis.
FIG. 158 is a graph illustrating a relationship between the rear end position of
the weld overlay section with respect to the weld bead end section and the maximum
value of the maximum main stress in the weld bead end section at each length of the
weld overlay section, which is obtained by the computer analysis.
FIG. 16A is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the weld bead end section is 30%.
- 11 -
FIG. 168 is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit ofthe front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the weld bead end section is 50%.
FIG. 16C is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the front end position of the weld overlay
section, when the decrease mte of the maximum value ofthe maximum main stress in
the weld bead end section is 75%.
FIG. 16D is a graph illustrating a relationship between the length of the weld
overl-ay section and the iowcr limit of the ii"ont end positioi1. 6Iihe weld overlay· · ·: ·
section, when the decrease rate of the maximum value ofthe maximum main stress in
the weld bead end section is 90%.
FIG. 17 A is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value ofthe maximum main stress in
the weld bead end section is 30%.
FIG. 178 is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the weld bead end section is 50%.
FIG. 17C is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the weld bead end section is 75%.
FIG. 170 is a graph illustrating a relationship between the length of the weld
- 12 -
overlay section and the upper limit of the front end position of the weld overlay
section, when the decrease rate of the maximum value of the maximum main stress in
the weld bead end section is 90%.
FIG. 18A is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the weld
bead end section is 30%.
FIG. 18B is a graph illustrating a relationship between the length of the weld
. overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the' •i\iaxittmm vai ue of the· maximum maili stress ·intlk •weld
bead end section is 50%.
FIG. 18C is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the weld
bead end section is 75%.
FIG. 18D is a graph illustrating a relationship between the length of the weld
overlay section and the lower limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the maximum main stress in the weld
bead end section is 90%.
FIG. 19A is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the ma"Ximum main stress in the weld
bead end section is 3 0%.
FIG. l9B is a graph illustrating a relationship between the length of the weld
overlay .section and the upper limit of the rear end position of the weld overlay section,
- 13 -
when the decrease rate of the maximum value of the maximum main stress in the weld
bead end section is 50%.
FIG. 19C is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the rear end position of the weld overlay section,
when the decrease rate ofthe maximum value ofthe maximum main stress in the weld
bead end section is 7 5%.
FIG. 190 is a graph illustrating a relationship between the length of the weld
overlay section and the upper limit of the rear end position of the weld overlay section,
when the decrease rate of the maximum value of the ri1aximum main stress in the weld
bead end section is 90'Yo. ·,' -~. -·: • ' c . .-:.... • -· .
FIG. 20 is a graph illustrating a relationship between a plate thickness and the
maximum value of the maximum main stress.
FIG. 21 is a graph illustrating a relationship between the plate thickness and
the maximum value of the maximum main stress.
FIG. 22 is a graph illustrating a relationship between the plate thickness and
the maximum value of the maximum main stress.
FIG. 23 is a graph illustrating a relationship between the plate thickness and
the maximum value of the maximum main stress.
FIG. 24 is a graph illustrating a relationship between an elongated bead length
(a separation distance Lw between the abutting end section and the weld bead end
section) and a base (the abutting end section)/a tip stress (the weld bead end section)
reversing plate thickness.
FIG. 25 is a diagram illustrating aT-joint of the related art.
[Embodiments of the Invention]
[0019]
- 14 -
The present inventors have conducted intensive studies about a configuration
in which a fatigue strength can be easily improved in aT-welded joint member
obtained by welding a front surface of a horizontal plate to an end surface of a vertical
plate with a weld bead. As a result thereof, the present inventors have newly found
that:
(a) in a case where a weld overlay bead is formed on a rear surface of the
horizontal plate (a surface on which a joint portion with respect to the vertical plate
does not exist), an effect of reducing a maximum main stress is high, and workability
is not impaired, and thus, it is possible to efficiently improve a fatigue strength,
compal'cd to·a•case"wherc the weld overlay bead is foimed on tlwfrofit'silrface of the
horizontal plate.
Further, the present inventors have newly found that:
(b) in the horizontal plate configuring the T-welded joint member, the value of
the maximum main stress which is generated in the vicinity of the joint portion
increases in the vicinity of an end section of the joint portion or in the vicinity of an
end section of the weld bead, and a fatigue fracture occurs from such a position;
(c) the maximum main stress in the vicinity of the end section of the joint
portion tends to be larger than the maximum main stress in the vicinity of the end
section of the weld bead as the thickness of the horizontal plate increases, and the
maximum main stress in the vicinity of the end section of the weld bead tends to be
larger than the maximum main stress in the vicinity of the end section of the joint
portion as the thickness of the horizontal plate decreases; and
(d) in a case where the vertical plate is pulled in a direction perpendicular to
the front surface of the horizontal plate, the direction of the maximum main stress
which is generated in the vicinity of the joint portion between the vertical plate and the
- 15 -
horizontal plate is parallel to a stretching direction of the joint portion or the weld
bead.
Hereinafter, the present invention will be described in detail on the basis of a
first embodiment and a second embodiment.
[0020]
<>
FIG. 1 is a perspective view illustrating a welded structure member lOA
according to a first embodiment ofthe present invention, FIG. 2 is a perspective view
ofthe welded structure member 1 OA seen from a lower side, FIG. 3 is. a side view
-iihJstrating a part-uftfle welded structUte member lOA, and'FlO. 4 is a 'prujection-vi'cw
of an abutting surface 32, a weld bead 24, and weld overlay sections 30a and 30b of
the welded structure member 1 OA. Furthermore, in FIG. 1 and FIG. 2, dotted circles
41a, 41b, 42a, 42b, 43a, 43b, 44a, 44b, 45a, and 45b illustrate positions of holes
formed on an analysis model in a simulation described below. The details thereof
will be described below.
[0021]
As illustrated in FIG. I, the welded structure member I OA according to this
embodiment includes a joined metal member 12 which extends in a first direction Dl,
a base metal member 14 which extends in a second direction D2 intersecting with the
first direction Dl and to which an end surface of the joined metal member 12 is joined,
the weld bead 24 which joins the joined metal member 12 to the base metal member
14, and the weld overlay sections 30a and 30b which are formed on a rear surface of
the base metal member 14.
The welded structure member I OA is a so-called T-joint, in which a joint
portion joins the joined metal member 12 and the base metal member 14 to have aT-
- 16 -
shape. In a case of projecting the welded stmcture member 1 OA according to this
embodiment in a direction parallel to a front surface 14a described below, the joint
portion between the joined metal member 12 and the base metal member 14 has aTshape.
[0022]
In the welded structure member I OA according to this embodiment, the first
direction Dl is perpendicular to the second direction D2, and the first direction 01
may be inclined to the second direction 02. That is, in the welded structure member
1 OA according to this embodiment, the joined metal member 12 is welded to the base
,. · metal member 14' to be perpe;ndicuiar to the base metal' memberl4·;·arid the·joiried• • •
metal member 12 may be welded to the base metal member 14 to be inclined to the
base metal member 14. Furthermore, in the following description, the first direction
01 is set to a vertical direction, and the second direction 02 is set to a right-left
direction.
[0023]
The joined metal member 12 is configured with a plate-like metal member.
In addition, the joined metal member 12 is configured with a plate-like section 121
having an opened cross-sectional shape. The plate-like section 121 ofthejoined
metal member 12 includes a pair of side wall sections 121a and 121b, and a bottom
wall section 12lc. The pair of side wall sections 121a and 121b is disposed in
parallel such that the surfaces of the side wall sections 121a and 121b face each other.
The bottom wall section 121c is disposed to connect one end section of the side wall
section 121a to one end section ofthe side wall section 121b.
[0024]
The base metal member 14 is configured with a plate-like metal member, and
- 17 -
·-~' ,-:
includes a front surface 14a and a rear surface 14b which are both surfaces each other.
In addition, the base metal member 14 is configured with a plate-like section 141
having an opened cross-sectional shape. The plate-like section 141 of the base metal
member 14 includes a pair of side wall sections 141a and 141b, and a top plate section
141 c. The pair of side wall sections 141 a and 141 b is disposed in parallel such that
the surfaces of the side wall sections 141a and 141b face each other. The top plate
section 141c is disposed to connect one end section.ofthe side wall section 14la to one
end section of the side wall section 141 b.
[0025]
In rhe following description, in a front surface of the basti metal membeii,i·4;a
section corresponding to a front surface of the top plate section 141c will be referred to
as the front surface 14a of the base metal member 14, and in the rear surface of the
base metal member 14, a section corresponding to a rear surface of the top plate
section 141 c will be referred to as the rear surface 14b of the base metal member 14.
In addition, a joint interface between the end surface of the joined metal
member 12 and the front surface 14a of the base metal member 14 will be referred to
as the abutting surface 32. Further, a direction towards a direction in which the
abutting surface 32 exists will be referred to as the rear, and the opposite direction
thereof will be referred to as the front, on the basis of abutting end sections 32a and
32b which are end sections of the abutting surface 32.
When the joined metal member 12 is welded to the base metal member 14, a
part of the joined metal member 12 and a part of the base metal member 14 are melted,
and thus, in a state of actually welding both of the members to each other, it is not
possible to obviously define the abutting surface 32 which is the joint interface.
Therefore, in the present invention, when the joined metal member 12 is welded to the
- 18 -
base metal member 14, the abutting surface 32 is defined by assuming that both of the
members are not melted (in other words, by assuming that the joined metal member 12
and the base metal member 14 maintain the shape before being welded). Therefore,
in the present invention, in a case where the abutting surface 32 and the end surface of
the joined metal member 12 are seen from a direction perpendicular to the front surface
14a of the base metal member 14, an outer edge of the abutting surface 32 is coincident
with an outer edge of the end surface of the joined metalmemberJ2.
[0026]
Each ofthe joined metal member 12 and the base metal member 14, for
example, can be obtained Dy'perfomnng bending with respecfto a llJctal'sheet 'fire
material of the metal sheet is not particularly limited, and may be steel or aluminum.
As an example, a steel sheet having a tensile strength of greater than or equal to 270
MPa can be used as the material of the joined metal member 12 and the base metal
member 14. In particular, in order to sufficiently ensure the strength of the welded
structure member lOA, it is preferable to use a steel sheet having a tensile strength of
greater than or equal to 590 MPa, it is more preferable to use a steel sheet having a
tensile strength of greater than or equal to 780 MPa, it is even more preferable to use a
steel sheet having a tensile strength of greater than or equal to 980 MPa, it is even
more preferable to use a steel sheet having a tensile strength of greater than or equal to
I, 180 MPa, and it is even more preferable to use a steel sheet having a tensile strength
of greater than or equal to 1,500 MPa, as the material of the joined metal member 12
and the base metal member 14.
[0027]
The thickness of the base metal member 14, for example, may be equivalent
to the thickness of a steel sheet which is well used as the material of a vehicle chassis
- 19 -
member. Specifically, the thickness of the base metal member 14 may be set to be in
a range of0.8 mm to 4.5 mm.
Here, a~ described below, in the welded structure member I OA according to
this embodiment, the weld overlay sections 30a and 30b are disposed to reduce a
maximum main stress in the vicinity of the abutting end sections 32a and 32b. The
maximum main stress in the vicinity of the abutting end sections 32a and 32b tends to
be larger than a maximum main stress in the vicinity of the weld bead end sections 24a
and 24b as the thickness of the base metal member 14 increases, and thus, in order to
reduce a maximum main stress of the welding metal member I OA according to this
· en'tl:lodimeut;· it- is eifeclive that the weld overlay seGtion·s 30a·and 3'0b are:dispose(hn
the vicinity of the abutting end sections 32a and 32b.
As a result of conducting further studies by the present inventors on the basis
of the tendency described above, it has been found that in the welded structure member
1 OA according to this embodiment, it is preferable to set a separation distance Lw
(mm) between the abutting end sections 32a and 32b and the weld bead end sections
24a and 24b, and a plate thickness T (mm) of the base metal member 14 to satisfy
Expression (A) described below.
-0.125Lw + 4.06 <:: T <:: 4.5 ... Expression (A)
Here, even in a case where Expression (A) is not satisfied, it is preferable that
the weld overlay sections 30a and 30b are disposed in the vicinity of the abutting end
sections 32a and 32b. This is because it is possible to reduce the maximum main
stress in the vicinity of the abutting end sections 32a and 32b.
Furthem10re, the thickness of the joined metal member 12 can be selected
according to the performance which is required for the member.
[0028]
- 20 -
)-.- c. ..
The weld bead 24 is formed approximately into an U-shape in the plan view
along the abutting surface 32, and the end surface of the joined metal member 12 is
joined to the front surface 14a of the base metal member 14.
Ii1 this embodiment, the weld bead 24 includes a side wall bead section 241 a
which joins the side wall section 121 a of the joined metal member 12 to the front
surface 14a of the base metal member 14, a side wall bead section 241 b which joins
the side wall section 121 b of the joined metal member 12 to the front surface 14a of
the base metal member 14, and a bottom wall bead section 241c which joins the
bottom wall section 121c of the joined metal member 12 to the tront surface 14a of the
· · 'base'metal n\ember 14,. ·The weld bead 24, for exa1hple, is 'formed ti"ya1'c ·wddi11g· ·
In this embodiment, the weld bead 24 is fom1ed from the front surface 14a of
the base metal member 14 to a predetermined depth position in a plate thickness
direction ofthe base metal member 14. That is, the weld bead 24 is formed not to
penetrate through the base metal member 14. Here, the weld bead 24 may be formed
to penetrate through the base metal member 14.
[0029]
The weld bead 24 includes the weld bead end sections 24a and 24b in each
position separated to the front from the abutting end sections 32a and 32b of the
abutting surface 32 between the joined metal member 12 and the base metal member
14. It is preferable that the separation distance Lw (mm) between the abutting end
sections 32a and 32b and the weld bead end sections 24a and 24b is set to satisfY
Expression (A) described above in consideration of the plate thickness T of the base
metal member 14.
Furthermore, a bead fom1ed between the joined metal member 12 and the
base metal member 14 is defined as the weld bead 24 hy assuming that the joined
- 21 -
metal member 12 and the base metal member 14 maintain the shape before being
welded.
[0030]
The weld overlay sections 30a and 30b are weld overlay beads which are not
involved in the joint between the base metal member 14 and the other member, and are
formed on the rear surface 14b ofthe base metalmember14 into the shape of a line, as
illustrated in FIG. 2 to FIG 4.
The weld overlay section 30a is disposed to correspond to the side wall
section 121a ofthe joined metal member 12, and the weld overlay section 30b is
' llisposed to correspond to the side wail section 12lb ofthejoined"mefalmeinber 12:'
The weld overlay sections 30a and 30b, for example, are formed by arc welding or
brazing by using a welding material. In a case where the weld overlay sections 30a
and 30b are formed by the arc welding, the weld overlay sections 30a and 30b are
formed to enter the base metal member 14, and thus, it is possible to reduce the
maximum main stress in the vicinity of the abutting end sections 32a and 32b and to
further improve a fatigue strength of the welded structure member.
[0031]
Furthermore, beads which are formed on the rear surface 14b of the plate-like
section 141 are defined as the weld overlay sections 30a and 30b by assuming that the
shape of the plate-like section 141 before forming the weld overlay sections 30a and
30b is maintained.
The weld overlay sections 30a and 30b are formed on the rear surface 14b of
the base metal member 14, and thus, a restriction on the manufacturing decreases
compared to a case of being formed on the front surface 14a of the base metal member
14. For example, even in a case where the plate-like section 121 is welded to the
- 22 -
plate-like section 141 by being greatly inclined, the weld overlay sections 30a and 30b
may be formed on the rear surface 14b of the plate-like section 141 but not between the
plate-like section 121 and the plate-like section 141, and thus, it is possible to easily
form the weld overlay sections 30a and 30b. Accordingly, it is possible to easily
manufacture the welded structure member I OA.
Further, in a case where the weld overlay sections 30a and 30b are formed on
the rear surfaceJ4b of the base metal member 14, for example, in a case where the
welded structure member 1 OA is used as a vehicle body material, it is possible to form
the weld overlay sections 30a and 30b in a position where the weld overlay sections
JOa and 30b are·not exposed-to the ~ippcar;~ncc. -fn this c'ase1 it'is possible !6prevenl
the sense of beauty of a vehicle body from being impaired by the weld overlay sections
30aand 30b.
[0032]
The length of each of the weld overlay sections 30a and 30b in a front -rear
direction may be greater than or equal to 6.0 mm, is preferably greater than or equal to
10.0 mm, is more preferably greater than or equal to 14.0 mm, and is even more
preferably greater than or equal to 20.0 mm.
The width of each of the weld overlay sections 30a and 30b is preferably
greater than or equal to 5.0 mm, and is more preferably greater than or equal to 6.0
mm. In addition, it is preferable that the width of each of the weld overlay sections
30a and 30b is greater than the thickness of the joined metal member 12, that is, the
width ofthe abutting surface 32. Even in a case where the width of the weld overlay
sections 30a and 30b is greater than 40.0 mm, an effect of reducing the maximum main
stress in the vicinity of the abutting end sections 32a and 32b is saturated, and a
component weight and a work rate increase. Therefore, the width of the weld overlay
- 23 -
1 ,-,
sections 30a and 30b is preferably less than or equal to 30.0 mm, and is more
preferably less than or equal to 20.0 mm.
As illustrated in FIG. 3, it is preferable that a height H of the weld overlay
section 30a, that is, a protruding height from the rear surface 14b of the base metal
member 14 is greater than or equal to 2.0 mm. Even in a case where the height H of
the weld overlay section 30a is greater than 20.0 mm, the effect of reducing the
maximum main stress in the vicinity of the abutting end sections 32a and 32b is.
saturated, and the component weight and the work rate increase. Therefore, the
height H of the weld overlay section 30a is preferably less than or equal to 20.0 mm,
and is mme preferab!y:ies5than or equal to iO.O ri1\n. 'Tlie'same applies·tothelieighl
of the weld overlay section 30b.
[0033]
In a case where the joined metal member 12 is pulled in a direction
perpendicular to the front surface of the base metal member 14, the direction of a
maximum main stress which is generated in the vicinity of an abutting end section of
the base metal member 14 is a direction parallel to a stretching direction of a abutting
surface. Accordingly, it is preferable that the weld overlay sections 30a and 30b are
formed to be approximately parallel to the abutting snrface 32.
In other words, it is preferable that the weld overlay sections 30a and 30b are
formed to be parallel to the stretching direction of the abutting surface, in the view of
facing the rear surface 14b of the base metal member 14 and of penetrating through the
base metal member 14. Specifically, it is preferable that the weld overlay section 30a
is approximately parallel to an abutting side surface 322a and the side wall bead
section 241 a, and the weld overlay section 30b is approximately parallel to an abutting
side surface 322b and the side wall bead section 241 b.
- 24 -
:Y (I ,•·'·.-.·
[0034]
Hereinafter, a positional relationship in the abutting surface 32, the weld bead
24, and the weld overlay sections 30a and 30b of the welded structure member lOA
according to this embodiment will be described.
[0035]
FIG. 4 is a diagram in which the abutting surface 32, the weld bead 24, and
the weld overlay sections 30a and 30b are projected in the direction perpendicular to
the front surface 14a of the base metal member 14 (in this embodiment, the first
direction Dl ). Furthermore, in FIG. 4, for the sake of easily understanding. the
positiorlal'rclatiomhijJ ill the abuttiug surface 32, the' weld bead'2'4; and fhe·weld .. ,
overlay sections 30a and 30b, a section is hatched in which the abutting surface 32 and
the weld bead 24 are projected. In addition, an outer edge of the section is illustrated
by a broken line in which the weld overlay sections 30a and 30b are projected.
[0036]
As illustrated in FIG. 4, in the welded structure member 1 OA according to this
embodiment, the abutting surface 32 includes a pair of abutting end sections 32a and
32b, and extends approximately into an U-shape from the abutting end section 32a
towards the abutting end section 32b. Specifically, the abutting surface 32 includes
the abutting side surfaces 322a and 322b, and an abutting bottom surface 322c. The
abutting bottom surface 322c is an abutting surface between the bottom wall section
12lc of the joined metal member 12 (refer to FIG. 1) and the plate-like section 141 of
the base metal member (refer to FIG 1 ). The abutting side surface 322a is an abutting
surface between the side wall section 12la (refer to FIG. I) and the plate-like section
141. The abutting side surface 322b is an abutting surface between the side wall
section 121 b (refer to FIG. I) and the plate-like section 141. The abutting side
- 25 -
'>' f ,' \ ~\ :
surface 322a linearly extends from the abutting bottom surface 322c towards one
abutting end section 32a of the abutting surface 32, and abutting side surface 322b
linearly extends from the abutting bottom surface 322c towards the other abutting end
section 32b of the abutting surface 32. In this embodiment, each of the abutting side
surfaces 322a and 322b corresponds to a linear section. Furthem1ore, in FIG. 4, each
of a boundary between the abutting bottom surface 322c and the abutting side surfaces
322a and 322b and a boundary between the bottom wall bead section 24lc.andthe side
wall bead sections 241a and 24lb is illustrated by a two-dot chain line.
[0037]
ln',tltb weitied structure member lOA according to thislcmbbiiimcti!;·alioM·
end of the weld overlay sections 30a and 30b is disposed on the front from a position
which is separated from the abutting end sections 32a and 32b to the rear by L9 mm,
and a rear end of the weld overlay sections 30a and 30b is disposed on the rear from a
position which is separated from the abutting end sections 32a and 32b to the rear by
7.0 mm, in the view of facing the rear surface 14b of the base metal member 14 and of
penetrating through the base metal member 14. That is, in the rear surface 14b of the
base metal member 14, the weld overlay section 30a is formed to cover a region
illustrated by cross-hatching in FIG. 3.
In addition, it is preferable that the front end of the weld overlay sections 30a
and 30b is positioned on the front from the abutting end sections 32a and 32b, the rear
end of the weld overlay sections 30a and 30b is positions on the rear from the abutting
end sections 32a and 32b, in the view of facing the rear surface 14b of the base metal
member 14 and of penetrating the base metal member 14.
The front end of the weld overlay sections 30a and 30b may extend up to the
vicinity of the weld bead end sections 24a and 24b. Specifically, the front end of the
- 26 -
weld overlay sections 30a and 30b may extend up to the tront from the position which
is separated from the weld bead end sections 24a and 24b to the rear by 0.1 mm. In
this case, it is also possible to reduce the maximum main stress in the vicinity of the
weld bead end sections 24a and 24b.
[0038]
As illustrated in FIG 4, the weld overlay sections 30a and 30b overlap the
abutting surface. 32 and the weld bead 24 in the vicinity of the abutting end sections
32a and 32b. Specifically, the weld overlay section 30a is disposed to correspond to
the abutting side surface 322a, and overlaps the abutting side surface 322a and the side
· ·. · wall liead·s\x.tiot124hdn the vicinity of the abutting end s·ecth.Jn'32."a'.· .. ~ The Weld····
overlay section 30b is disposed to correspond to the abutting side surface 322b, and
overlaps the abutting side surface 322b and the side wall bead section 241 b in the
vicinity of the abutting end section 32b.
Furthermore, in an example illustrated in FIG. 4, the weld overlay sections
30a and 30b overlap the abutting surface 32 and the weld bead 24, and the weld
overlay sections 30a and 30b may overlap only one of the abutting surface 32 and the
weld bead 24.
[0039]
It is preferable that the rear end of the weld overlay section 30a is disposed on
the rear from a position which is separated from the abutting end sections 32a and 32b
to the rear by 8.0 mm, it is more preferable that the rear end of the weld overlay section
30a is disposed on the rear from a position which is separated from the abutting end
sections 32a and 32b to the rear by I 0.0 mm, and it is even more preferable that the
rear end of the weld overlay section 30a is disposed on the rear from a position which
is separated from the abutting end sections 32a and 32b to the rear by 14.0111111.
- 27 -
. ;, .
[0040]
It is preferable that the front end of the weld overlay section 30a is disposed
on the front from a position which is separated from the abutting end sections 32a and
32b to the rear by 0.4 mm, it is more preferable that the front end of the weld overlay
section 30a is disposed on the front from a position which is separated from the
abutting end sections 32a and 32b to the front by 0.3 mm, it is even more preferable
that the front end of the weld overlay section 30a is disposed on.the front from a
position which is separated from the abutting end sections 32a and 32b to the front by
0.7 mm, and it is even more preferable that the front end of the weld overlay section
· · ,, JOa· is disposed m\ the fronttront :1 position which. is\ sbparated~tioni the abutting end'
sections 32a and 32b to the front by 1.7 mm
[0041]
A manufacturing method of the welded structure member I OA includes a weld
bead applying step of applying the weld bead 24 which joins the end surface of the
joined metal member 12 to the front surface 14a of the base metal member 14, and a
weld overlay section applying step of applying the weld overlay sections 30a and 30b
onto the rear surface 14b of the base metal member 14 by arc welding or brazing.
Any one ofthe weld bead applying step and the weld overlay section applying step
may be performed first, and it is preferable that the weld bead applying step is
performed, and then, the weld overlay section applying step is performed, from the
viewpoint of workability.
[0042]
According to the configuration described above, rigidity in the vicinity of the
abutting end sections 32a and 32b is increased by the weld overlay sections 30a and
30b, and thus, it is possible to reduce the maximum main stress. Therefore, it is
- 28 -
possible to increase the fatigue strength of the welded structure member lOA
[0043]
In FIG. 5, a welded structure member lOA' according to a modification
example of this embodiment is illustrated. In the welded structure member 1 OA
according to the first embodiment described above, a case where the side wall section
12la and the side wall section 121 bare disposed to be parallel to each other has been
.described, but the side wall section 121 a and the side wall section 121 b may not be
disposed to be parallel to each other. For example, in a case where the plate-like
section 121 has an opened cross-sectional shape in which an opening end side is
· · opened, a projeetion view·of the abuttiog surface 32;the \'veld bead24, and the weld ,
overlay sections 30a and 30b becomes the drawing illustrated in FIG. 5. In this case,
in each of the abutting side surfaces 322a and 322b, the front-rear direction is defined
by setting the abutting bottom surface 322c side to the rear, and by setting the opposite
side thereof to the front. Then, as with the welded structure member lOA according
to the first embodiment, the positional relationship in the abutting surface 32, the weld
bead 24, and the weld overlay sections 30a and 30b is defined on the basis of the frontrear
direction which is defined with respect to each of the abutting side surfaces 322a
and 322b.
[0044]
<>
Next, a welded structure member 1 OB according to a second embodiment of
the present invention will be described. The welded structure member 108 according
to the second embodiment has the same configuration as that ofthe welded structure
member I OA according to the first embodiment except for the position where the weld
overlay sections 30a and 30b are formed, and thus, the same reference numerals are
- 29 -
applied to the same constituents, and the description thereof will be omitted. ·
[0045]
In FIG 6.to FIG 9, the welded structure member lOB according to the second
embodiment is illustrated. More specifically, FIG 6 is a perspective view of the
welded structure member I OB seen from an upper side, FIG 7 is a perspective view of
the welded structure member I OB seen from a lower side, FIG. 8 is a side view
illustrating a part ofthe welded structure member.10B, and FIG. 9 is a projection view
of the abutting surface 32, the weld bead 24, and the weld overlay sections 30a and 30b
of the welded structure member JOB.
[0046]
The welded structure member 1 OA according to the first embodiment
described above and the welded structure member lOA' according to the first
modification example thereof has a configuration in which the weld overlay sections
30a and 30b are disposed in a region corresponding to the vicinity of the abutting end
sections 32a and 32b, in the rear surface 14b of the base metal member 14.
According to such a configuration, it is possible to reduce the maximum main stress in
the vicinity of the abutting end sections 32a and 32b, and to obtain an effect of
increasing the fatigue strength of the welded structure member I OA.
On the other hand, the welded structure member lOB according to the second
embodiment has a configuration in which the weld overlay sections 30a and 30b are
disposed in a region in the vicinity of the weld bead end sections 24a and 24b, in the
rear surface l4b of the base metal member 14. According to such a configuration, it
is possible to reduce the maximum main stress in the vicinity of the weld bead end
sections 24a and 24b, and to obtain an effect of increasing a fatigue strength of the
welded structure member I OB.
- 30 -
[0047]
As with the welded structure member I OA according to the first embodiment,
each of the thickness of the joined metal member 12 and the thickness of the base
metal member I 4 of the welded structure member 1 OB according to the second
embodiment, for example, may be set to be in a range of 0.8 mm to 4.5 mm.
Here, in the welded structure member I OB according to the second
embodiment, the weld overlay sections 30a and 30b are disposed to reduce the
maximum main stress in the vicinity of the weld bead end sections 24a and 24b. The
maximum main stress in the vicinity of the weld bead end sections 24a and 24b tends
to be larger than the ·maximum main :>lress in the vicinity ofthe' abutting end sections
32a and 32b as the thickness of the base metal member 14 decreases. Accordingly, in
the welded structure member I OB according to this embodiment aimed at reducing the
maximum main stress in the vicinity of the weld bead end sections 24a and 24b, in
order to reduce the maximum main stress, it is effective that the weld overlay sections
30a and 30b are disposed in the vicinity of the weld bead end sections 24a and 24b.
As a result of conducting further studies by the present inventors on the basis
of the tendency described above, it has been found that in the welded structure member
I OB according to this embodiment, it is preferable to set the separation distance Lw
(mm) between the abutting end sections 32a and 32b and the weld bead end sections
24a and 24b, and the plate thickness T (mm) of the base metal member 14 to satisfy
Expression (B) described below.
0.8 mm <:: T < -0.125Lw + 4.06 mm ... Expression (B)
Here, even in a case where Expression (B) is not satisfied, it is preferable that
the weld overlay sections 30a and 30b are disposed in the vicinity of the weld bead end
sections 24a and 24b. This is because it is possible to reduce the maximum main
- 31 -
stress in the vicinity of the weld bead end sections 24a and 24b.
Furthennore, the thickness of the joined metal member 12 can be selected
according to the perfonnance which is required for the member.
[0048]
Hereinafter, the positional relationship in the abutting surface 32, the weld
bead 24, and the weld overlay sections 30a and 30b ofthe welded structure member
108 according to the second embodiment will be described.
[0049]
As illustrated in FIG. 8, in the welded structure member 108 according to this
· ·' •' : .... ·· · . · · embodiment, the front ~nd oft-he weld overlay sectiims' 30a m1d 30b ·is disposed mrc(he
front from a position which is separated from the weld bead end sections 24a and 24b
to the rear by 0.1 mm, and the rear end of the weld overlay sections 30a and 30b is
disposed on the rear from a position which is separated from the weld bead end
sections 24a and 24b to the rear by 3. 0 mm, in the view offacing the rear surface 14b
of the base metal member 14 and of penetrating through the base metal member 14.
[0050]
Furthennore, in an example illustrated in FIG. 8, the front end of the weld
overlay sections 30a and 30b is positioned on the front from the weld bead end
sections 24a and 24b, and the rear end of the weld overlay sections 30a and 30b is
positioned on the rear from the weld bead end sections 24a and 24b. However, the
front end of the weld overlay sections 30a and 30b may be disposed on the rear from
the weld bead end sections 24a and 24b.
[0051]
It is preferable that the rear end of the weld overlay section 30a is disposed on
the rear from a position which is separated from the weld bead end sections 24a and
- 32 -
24b to the rear by 5.0 mm, and it is more preferable that the rear end of the weld
overlay section 30a is disposed on the rear from a position which is separated from the
weld bead end sections 24a and 24b to the rear by 10.0 mm.
[0052]
It is preferable that the front end of the weld overlay section 30a is disposed
on the front from a position which is separated from the weld bead end sections 24a
and 24b to the front by 0.3 mm, and it is more preferable that the front end of the weld
overlay section 30a is disposed on the front from a position which is separated from
the weld bead end sections 24a and 24b to the front by 1.2 mm, and it is even more
· ptercrable that the ironr·end of the weld overlay sectim130a is dispO-sed {)n·thc front
from a position which is separated from the weld bead end sections 24a and 24b to the
front by L9 mm.
[0053]
As described above, the present invention has been described on the basis of
the first embodiment and the second embodiment, but the present invention is not
limited only to the embodiments described above, and various changes can be
performed within the scope of claims.
[0054]
For example, the first embodiment in which the weld overlay sections 30a and
30b are disposed in the vicinity of the abutting end sections 32a and 32b and the
second embodiment in which the weld overlay sections 30a and 30b are disposed in the
vicinity of the weld bead end sections 24a and 24b are combined, and thus, the weld
overlay sections 30a and 30b may be disposed from the vicinity of the abutting end
sections 32a and 32b over the vicinity of the weld bead end sections 24a and 24b. In
this case, the weld overlay sections 30a and 30b may be divided between the abutting
- 33 -
. · ,-. I.-.
end sections 32a and 32b and the weld bead end sections 24a and 24b.
[0055]
In addition, in the first embodiment and the second embodiment described
above, a case where the weld overlay sections 30a and 30b are formed in the vicinity
of both of the abutting end sections 32a and 32b or in the vicinity of both of the weld
bead end sections 24a and 24b has been described, but any one of the weld overlay
sections 30a and 30b may not be fonned.
[0056]
In addition, in the first embodiment or the.second embodiment described
above, 11uase where'the ·weld overlay sections JOa·afid'30b formed to extend td.be
approximately parallel to the abutting surface 32 or the weld bead 24 has been
described, but the weld overlay sections 30a and 30b may be formed to extend to a
direction inclined to the abutting surface 32 or the weld bead 24. Even in a case
where the weld overlay sections 30a and 30b are formed to extend to the direction
inclined to the abutting surface 32 or the weld bead 24, the weld overlay sections 30a
and 30b are disposed over a position which is separated from the abutting end sections
32a and 32b to the rear by 1.9 mm to 7.0 mm or a position which is separated from the
weld bead end sections 24a and 24b to the rear by 0.1 mm to 3.0 mm, and thus, it is
possible to reduce the maximum main stress in the vicinity of the abutting end sections
32a and 32b or in the vicinity of the weld bead end sections 24a and 24b, and to obtain
an effect of increasing the fatigue strength of the welded structure member.
[0057]
In addition, in the first embodiment and the second embodiment described
above, the plate-like section 121 has an opened cross-sectional shape which is opened
in a direction orthogonal to the first direction 01 and the second direction 02, but the
- 34 -
plate-like section 121 may have an opened cross-sectional shape which is opened in
the second direction D2.
[0058]
In addition, in the first embodiment and the second embodiment described
above, a case where the entire joined metal member 12 is configured as the plate-like
section 121 has been described, but the joined metal member 12 may include a section
(for example, a columnar section) having a shape other than that.ofthe plate-like.
section insofar as a joining surface between the joined metal member 12 and the base
metal member 14 has an opened cross-sectional shape. The joined metal member 12,
for exarnple, may be a rectangular coiumn having an acute aflgle.'' ·. •· 'h :.• ·'' • ·. • ·•·
[0059]
In addition, in tbe first embodiment and the second embodiment described
above, a case where the plate-like section 121 has an opened cross-sectional shape has
been described, but the present invention can be applied to a welded structure member
which includes a plate-like section having various shapes. Therefore, for example,
the joined metal member 12 may includes a plate-like section having a simply flat
shape, a plate-like section having an L-shaped cross section or a plate-like section
having an H-shaped cross section, instead of the plate-like section 121 described
above.
[0060]
In addition, in the first embodiment and the second embodiment described
above, the base metal member 14 including the side wall sections 141 a and 141 b has
been described, but the present invention can be applied to a welded structure member
which includes various base metal members including a flat plate section. Therefore,
the base metal member may not include the side wall sections I 41 a and 141 b.
- 35 -
[0061]
In addition, in the first embodiment and the second embodiment described
above, a case where the joining surface between the base metal member 14 and the
joined metal member 12 is a flat surface has been described, but the present invention
may also be applied to a welded structure member in which the joining surface
between the base metal member 14 and the joined metal member 12 is a curved
surface.
[0062]
In addition, in the first embodiment and the second embodiment described
·above, a•casc where the wdd bead 24 includes ihe' bottom -waU·bead·section·•ibN·chas
been described, but the weld bead may not include the bottom wall bead section.
[0063]
(Examination l based on Simulation)
Hereinafter, a simulation result using a computer and the effect ofthe
configuration according to the first embodiment will be described in more detail. In
this simulation, an analysis model (hereinafter, also referred to as a first model) having
the same configuration as that of the welded structure member lOA illustrated in FIGS.
I to 4 was prepared. Then, in the first model, the position and the length of the weld
overlay sections 30a and 30b in the front-rear direction were changed, the maximum
main stress which was generated in the vicinity of the abutting end sections 32a and
32b of the abutting surface 32 was obtained. In addition, an analysis model not
including the weld overlay sections 30a and 30b (hereinafter, also referred to as a
second model) was prepared for comparison, and the maximum main stress which was
generated in the vicinity of the abutting end sections 32a and 32b of the abutting
surface 32 was obtained.
- 36 -
[0064]
Furthermore, in both of the first model and the second model, holes were
formed in positions illustrated by the dotted circles 41a, 41b, 42a, 42b, 43a, 43b, 44a,
44b, 45a, and 45b in FIG. 1 and FIG. 2 (hereinafter, each of the holes illustrated by the
dotted line will be referred to as a hole). In the simulation, a fixing jig (a rigid body)
was disposed on each of the holes 42a, 42b, 43a, 43b, 44a, 44b, 45a, and 45b, and the
base metal member 14 was fixed. Then, a columnar member (a rigid body)
penetrated through the holes 41a and 41 b, the plate-like section 121 (the joined metal
member 12) was pulled in a direction perpendicular to the front surface 14a of the
plat<:·like section 141 by a force of2..0 kN through'them·ember:• '· ·· I,>'
,' !· '• \ r• '
[0065]
The configuration of both of the first model and the second model was
defined as described below. Furthermore, as described above, in the first model, the
position of the weld overlay sections 30a and 30b in the front-rear direction was
variously changed.
[0066]
(Configuration of Analysis Model)
· Joined Metal Member
Material: Steel
Thickness: 2.6 mm
Height (Length in First Direction D1): 80 mm
Length in Right-Left Direction (Second Direction D2): 70 111m
Length in Front-Rear Direction (refer to FIG. 4): 80 111111
Position of Hole 4la: Center of Side Wall Section121a
Position of Hole 41b: Center of Side Wall Section 121b
- 37 -
'· .. -· 'i'.
,, -;. ..
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
· Base Metal Member
Material: Steel
Thickness: 2.6 mm
Height (Length in First Direction Dl): 50 mm
Length in Right-Left Direction (Second Direction D2): 300 mm
Length in Front-Rear Direction (refer to FIG. 4): 150 mm
Center-to-Center Distance between Holes 42a and 42b: 230 mm
CeilteHo-Ccntcr Distance bctwe\;r'PHdles'43trand43b:·230 mm- r· ·
Center-to-Center Distance between Holes 44a and 44b: 230 mm
Center-to-Center Distance between Holes 45a and 45b: 230 mm
Center-to-Center Distance between Holes 42a and 43a: 100 mm
Center-to-Center Distance between Holes 42b and 43b: 100 mm
Distance in Vertical Direction from Front Surface 14a to Center of
Holes 44a, 44b, 45a, and 45b: 25 mm
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
·Weld Bead
Width (Width of Section Excluding Section Protruding from
Abutting End Sections 32a and 32b (refer to FIG. 4) to Front): 4.3 mm
Height (Height of Section Excluding Section Protruding from
Abutting End Sections 32a and 32b to Front): 5.0 mm
Width (Width of Section Protruding from Abutting End Sections 32a
and 32b to Front): 10.6 mm
- 38 -
Height (Height of Section Protruding from Abutting End Sections
32a and 32b to Front): 2.2 mm
Protrusion Amount (Distance Lw) from Abutting End Sections 32a
and 32b: 13.7 mm
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
· Weld Overlay Section (First Model)
Width: 6.0 mm
Height 2.0 mm
:, tetigth: 10:0 mm, 12.0 nun, 14.0 mm, 16.0 mm, 19:8·mm; 2J:6cmrn,
26.0 mm, and 28.0 mm
Position of Weld Overlay Section30a in Right-Left Direction: Center
Line of Weld Overlay Section 30a is Coincident with Left Edge of Abutting Side
Surface 322a (refer to FIG. 4)
Position of Weld Overlay Section 30b in Right-Left Direction: Center
Line of Weld Overlay Section 30b is Coincident with Right Edge of Abutting Side
Surface 322b (refer to FIG. 4)
[0067]
Young's Modulus: 2 I 0,000 MPa
Poisson's Ratio: 0.3
Furthermore, in a case where the analysis is performed in consideration of the
yield of the material of the joined metal member 12 and the base metal member 14 and
in a case where the analysis is perfonned without consideration of the yield, a
magnitude relationship between a stress generated in the first model and a stress
generated in the second model is not changed. Therefore, in a case where a
- 39 -
magnitude relationship between the maximum main stress generated in the first model
and the maximum main stress generated in the second model is relatively evaluated,
the presence or absence of the yield of the material may not be considered.
Therefore, in this simulation, in order to simplifY the analysis, elastic property analysis
was performed without consideration of the yield of the material of the joined metal
member 12 and the base metal member 14. In addition, in a case where the
magnitude relationship between the maximum main stresses is relatively evaluated as
described above, the yield of the material may not be considered, and thus, it is
possible to evaluate the welded structure member including the joined metal member
L~ and the base-nl'etai member 14 having an arbitrary tensile strength by: this·: · "'·:·
simulation. That is, for example, it is possible to evaluate a welded structure member
using a material having a tensile strength of270 MPa, and to evaluate a welded
structure member using a material having a tensile strength of 1,500 MPa, by this
simulation.
[0068]
In FIG lOA, a relationship between a front end position of the weld overlay
section 30a and a maximum value of the maximum main stress which is generated in
the vicinity of the abutting end section 32a at each length of the weld overlay section
30a (refer to FIG 4) is illustrated. Furthermore, the front end position of the weld
overlay section 30a indicates the position of the front end of the weld overlay section
30a in the front-rear direction in a case of being on the basis of the abutting end section
32a (refer to FIG 4). In FIG lOA, in a case where the front end of the weld overlay
section 30a is positioned on the front from the abutting end section 32a, the front end
position of the weld overlay section 30a is represented by a positive value, and in a
case where the front end of the weld overlay section 30a is positioned on the rear from
- 40 -
' ·~ j ."' ·'"I; ' < ,.\ •
the abutting end section 32a, the front end position of the weld overlay section 30a is
represented by a negative value. For example, in the welded structure member lOA
illustrated in FIG. 4, the front end of the weld overlay section 30a is positioned on the
front from the abutting end section 32a, and thus, the front end position of the weld
overlay section 30a is represented by a positive value. In addition, in FIG. lOA, the
maximum value (830 MPa) of the maximum main stress in the analysis model not
including the weld overlay sections 30a and 30b is illustrated by a broken line.
Furthermore, even though the description is omitted, a relationship between the front
end position of the weld overlay section 30b and a maximum value ofthe maximum
mahntress whicit i's•g;vneratcd in the vicinity of thii' abutting 'end sectidn3'2!J'also i '
became the same relationship as that illustrated in FIG. I OA.
[0069]
In FIG. I08, a relationship between the rear end position of the weld overlay
section 30a and the maximum value of the maximum main stress which is generated in
the vicinity of the abutting end section 32a at each length of the weld overlay section
30a (refer to FIG. 4) is illustrated. Furthermore, the rear end position of the weld
overlay section 30a indicates the position of the rear end of the weld overlay section
30a in the front-rear direction in a case of being on the basis of the abutting end section
32a (refer to FIG. 4). In FIG. I 08, in a case where the rear end of the weld overlay
section 30a is positioned on the front from the abutting end section 32a, the rear end
position of the weld overlay section 30a is represented by a positive value, and in a
case where the rear end of the weld overlay section 30a is positioned on the rear from
the abutting end section 32a, the rear end position of the weld overlay section 30a is
represented by a negative value. For example, in the welded structure member I OA
illustrated in FIG. 4, the rear end of the weld overlay section 30a is positioned on the
- 4 I -
·' l! .
rear from the abutting end section 32a, and thus, the rear end position of the weld
overlay section 30a is represented by a negative value. In addition, as with FIG. I OA,
in FIG. I 08, the maximum value (830 MPa) of the maximum main stress in the
analysis model not including the weld overlay sections 30a and 30b is illustrated by a
broken line. Furthem10re, even though the description is omitted, a relationship
between the rear end position of the weld overlay section 30b and the maximum value
of the maximum main stress which is generated in the vicinity of the abutting.end
section 32b became the same relationship as that illustrated in FIG. 108.
[0070]
Fron't FiG. ·lilA and-FIG. 108, it is kt1own -thahtccordiilg to;the'pre-s~nr i · ,·,,
invention, the front end position and the rear end position of the weld overlay sections
30a and 30b are suitably set, and thus, it is possible to reduce the maximum value of
the maximum main stress of the abutting end sections 32a and 32b of the abutting
surface 32. Specifically, from FIG. 1 OA, it is known that even in a case where the
length of the weld overlay sections 30a and 30b is short, which is 10.0 mm, the front
end position of the weld overlay sections 30a and 30b is set to be less than or equal to
8.0 mm, and to be preferably less than or equal to 7.0 mm, and thus, it is possible to
reliably reduce the maximum value of the maximum main stress compared to a case
where the weld overlay section does not exist. In addition, it is known that the front
end position ofthe weld overlay sections 30a and 30b is set to be 0 to 6.0 mm, to be
preferably 0 to 4.0 mm, and to be more preferably 2.0 to 4.0 mm, and thus, it is
possible to sufficiently reduce the maximum value of the maximum main stress. In
addition, as it is known from FIG. I 08, the rear end position of the weld overlay
sections 30a and 30b was set to be less than or equal to · 3.6 mm regardless of the
length of the weld overlay sections 30a and 30b, and thus, it was possible to reduce the
- 42 -
maximum value of the maximum main stress compared to a case where the weld
overlay section does not exist. In addition, from FIG. I OA and FIG. 108, it is known
that in a ca~e where the length of the weld overlay sections 30a and 30b is greater than
or equal to 14.0 mm, the effect of reducing the stress particularly increases, and in a
case where the length of the weld overlay sections 30a and 30b is greater than or equal
to 19.8 mm, the effect of reducing the stress is approximately the same. From this, it
is known that it is preferable that the length of the weld overlay sections 30a and 30b is
greater than or equal to 14.0 mm, and in order to maximally exhibit the effect of the
present invention, it is more preferable that the length of the weld overlay section is
greater thai1 or equal to 'l9.S·mrn.
[0071]
(Examination 2 based on Simulation)
With reference to FIG. I OA, in the simulation described above, in a case
where the length of the weld overlay sections 30a and 30b was I 0.0 mm, the maximum
value of the maximum main stress decreased to 7 60 MPa when the front end position
of the weld overlay sections 30a and 30b was 3.0 mm. As described above, the
maximum value of the maximum main stress in the analysis model not including the
weld overlay section was 830 MPa. Therefore, it is known that the weld overlay
sections 30a and 30b are disposed, and thus, the maximum value of the maximum main
stress maximally decreases by 70 MPa. At this time, when a decrease rate ofthe
maximum value of the maximum main stress (a decrease rate of the maximum value of
the maximum main stress with respect to the analysis model not including the weld
overlay section) was set to 100%, the front end position of the weld overlay sections
30a and 30b at the time that the decrease rate became 30% (a decrease of21 MPa) was
-2.5 mm and 7.0 mm. That is, in a case where the front end position of the weld
- 43 -
~, '.'; '
overlay sections 30a and 30b is in a range of -2.5 mm to 7.0 mm, it is possible to set
the decrease rate of the maximum value of the maximum main stress (hereinafter,
simply referred to as a decrease rate) to be greater than or equal to 30%. That is, a
lower limit of the trout end position of the weld overlay sections 30a and 30b for
setting the decrease rate to be greater than or equal to 30% is -2.5 mm, and an upper
limit thereof is 7.0 mm.
[0072)
Similarly, in a case where the length of the weld overlay sections 30a and 30b
is 12.0 mm, the maximum value of the maximum main stress when the front e.nd
· ·pusitioaul'tlleweld ovel'iaY sections 30a and 30b-was J.t:!mm decreased tci 752 MPa.
As described above, the maximum value of the maximum main stress in the analysis
model not including the weld overlay section was 830 MPa. Therefore, it is known
that the weld overlay sections 30a and 30b are disposed, and thus, the maximum value
of the maximum main stress maximally decreases by 78 MPa. At this time, when the
decrease rate was set to 100%, the front end position of the weld overlay sections 30a
and 30b at the time that the decrease rate became 30% (a decrease of23.4 MPa) was-
2.3 mm and 8. 7 mm. That is, the lower limit of the front end position of the weld
overlay sections 30a and 30b for setting the decrease rate to be greater than or equal to
30% is -2.3 mm, and the upper limit thereof is 8. 7 mm.
[0073)
Even though the detailed description is omitted, in a case where the length of
the weld overlay sections 30a and 30b was 14.0 mm, 16.0 mm, 19.8 mm, 23.6 nm1, and
28.0 mm, the same examination was also performed with respect to the position of the
weld overlay sections 30a and 30b for setting the decrease rate to be greater than or
equal to 50%, to be greater than or equal to 75%, and to be greater than or equal to
- 44 -
90%. Further, in the first model described above, the thickness of the base metal
member 14 was set to 3.5 mm and 3.0 mm, and the same simulation as that described
above was performed. Then, the same examination was performed with respect to a
relationship between the decrease rate and the weld overlay sections 30a and 30b.
Fnrthermore, in a case where the thickness of the base metal member 14 was 3.5 mm
and 3.0 mm, the length of the weld overlay sections 30aand 30b was set to 10.0 mm,
12.0 mm, 14.0 mm, 16.0 mm, 20.0 mm, 24.0 mm, and 28.0 mm. Examination results
thereof are shown in FIG. 11A to FIG. 14D along with examination results in a case
where the thickness of the base metal member 14 is.2.6 mm.
[0074]
As it is known from FIG. llA, in a case where the lower limit of the front end
position of the weld overlay sections 30a and 30b is greater than or equal to -1.9 nun, it
is possible to set the decrease rate to be at least 30% regardless of the thickness of the
base metal member 14 and the length of the weld overlay sections 30a and 30b. In
other words, (A) the front end of the weld overlay sections 30a and 30b is positioned
on the front from a position which is separated from the abutting end sections 32a and
32b to the rear by 1.9 mm, and thus, the decrease rate of at least 30% can be realized.
In addition, from FIGS. 11B, 11 C, and 11D, it was known that it was preferable that
the front end of the weld overlay sections 30a and 30b was positioned on the front
from a position which was separated from the abutting end sections 32a and 32b to the
rear by 0.4mm, it was more preferable that the front end of the weld overlay sections
30a and 30b was positioned on the front from a position which was separated from the
abutting end sections 32a and 32b to the front by 0. 7 mm, and it was even more
preferable that the front end of the weld overlay sections 30a and 30b was positioned
on the front from a position which was separated from the abutting end sections 32a
- 45 -
and 32b to the front by 1. 7 mm.
[0075]
As it is known from FIG. 12A, an upper limit of the front end position of the
weld overlay sections 30a and 30b at the time that the decrease rate became 30%
increased according to an increase in the length of the weld overlay sections 30a and
30b. As illustrated in FIG. 12B and FIG. I2C, such a relationship was also confirmed
in a case where the decrease rate was 50% and 75%. In contrast, as illustrated in FIG.
12D, in a case where the decrease rate was 90%, the upper limit of the front end
position of the weld overlay sections 30a and 30b did not greatly increase even in a
case:whcrethe length oflhe wdd overlay sectiOns 30aand30b'increased.
Specifically, in a case where the upper limit of the front end position of the weld
overlay sections 30a and 30b was less than or equal to 7.5 mm, it was possible to set
the decrease rate to be at least 90% regardless of the length of the weld overlay
sections 30a and 30b. From the result shown in FIG. 12D, it is known that the front
end of the weld overlay sections 30a and 30b is preferably positioned in a position
which is separated from the abutting end sections 32a and 32b (refer to FIG. 4) to the
front by 7.5 mm, is more preferably positioned on the rear from a position which is
separated from the abutting end sections 32a and 32b to the front by 7.0 mm, and thus,
it is possible to sufficiently decrease the maximum value of the maximum main stress.
[0076]
As it is known from FIG. 13A, a lower limit of the rear end position of the
weld overlay sections 30a and 30b at the time that the decrease rate became 30%
decreased according to an increase in the length of the weld overlay sections 30a and
30b. As illustrated in FIGS. 13B, 13C, and 13D, such a relationship was also
confinned in a case where the decrease rate was 50%, 75%, and 90%.
- 46 -
In addition, as illustrated in FIGS. 14B, 14C, and 14D, an upper limit of the
rear end position ofthe weld overlay sections 30a and 30b at the time that the decrease
rate was 50%, 75%, and 90% decreased according to an increase in the length of the
weld overlay sections 30a and 30b. In contrast, as illustrated in FIG l4A, in a case
where the decrease rate was 30%, the upper limit of the rear end position of the weld
overlay sections 30a and 30b.did not greatly decrease even in a case where the length
of the weld overlay sections 30a and 30b increased.
[0077]
Furthermore, as it is known from FIG l4A, in a case where the plate .
thicktiess ofthe base tiletalnKmbtx 14 is 2. 6 tmn;·i-nsofar·as the upper ·limit of\ th(r'reat
end position of the weld overlay sections 30a and 30b is less than or equal to -7.0 mm,
it is possible to set the decrease rate to be at least 30% regardless of the length of the
weld overlay sections 30a and 30b. Here, the maximum value of the maximum main
stress which is generated in the vicinity of the abutting end sections 32a and 32b is ·
higher in a case where the thickness of the base metal member 14 is 3.0 mm than in a
case where the thickness of the base metal member 14 is 3. 5 mm, and is higher in a
case where the thickness ofthe base metal member 14 is 2.6 mm than in a case where
the thickness ofthe base metal member 14 is 3.0 mm. Therefore, in particular, in a
case where the thickness of the base metal member 14 decreases, it is preferable to
increase the decrease rate. From such a viewpoint, it is preferable that the upper limit
of the rear end position of the weld overlay sections 30a and 30b is less than or equal
to -7.0 mm. In other words, (B) the rear end of the weld overlay sections 30a and 30b
is positioned on the rear from a position which is separated from the abutting end
sections 32a and 32b to the rear by 7.0 mm, and thus, the decrease rate of at least 30%
can be realized. Accordingly, it is possible to sufficiently reduce the maximum value
- 47 -
of the maximum main stress which is generated in the vicinity of the abutting end
sections 32a and 32b, and thus, even in a case where the thickness of the base metal
member 14 decreases, it is possible to sufficiently ensure the fatigue strength of the
welded structure member 10.
[0078]
In consideration of (A) and (B) described above, in order to more reliably
realize the decrease rate of greater than or equal to 30%, it is preferable thatthe weld
overlay sections 30a and 30b are disposed over a position which is separated at least
from the abutting end sections 32a and 32b to the rear by 1.9 mm to 7.0 mm.
[0079] :-'· (.l!
In addition, in consideration of 90% at which an improvement rate is further
improved, as illustrated in FIG liD and FIG 12D, both of the upper limit and the
lower limit of the front end position of the weld overlay section are positive values.
In addition, as illustrated in FIG !3D and FIG 14D, both of the upper limit and the
lower limit of the rear end position of the weld overlay section are negative values.
From this, in order for better improvement, it is preferable that the weld overlay
sections 30a and 30b are disposed to cross the abutting end sections 32a and 32b.
[0080]
(Examination 3 based on Simulation)
Hereinafter, a simulation result using a computer and the effect ofthe
configuration according to the second embodiment will be described in more detail.
In this simulation, an analysis model (hereinafter, also referred to as a third model)
having the same configuration as that of the welded structure member lOB illustrated
in FIGS. 6 to 9 was prepared. Then, in the third model, the maximum main stress
which was generated in the vicinity of the weld bead end sections 24a and 24b was
- 48 -
obtained by changing the position and the length of the weld overlay sections 30a and
30b in the front-rear direction. In addition, an analysis model not including the weld
overlay sections 30a and 30b (hereinafter, also referred to as a fourth model) was
prepared for comparison, and the maximum main stress which was generated in the
vicinity of the weld bead end sections 24a and 24b was obtained.
[0081]
Furthermore, in both of the third model and the fourth model, holes were
formed in positions illustrated by the dotted circles 4la, 41b, 42a, 42b, 43a, 43b, 44a,
44b, 45a, and 45b in FIG. 6 and FIG. 7 (hereinafter, each ofthe holes illustrated by the
·.. . dotted Jinewillbe rekm':d· t,ras a hole). in the simulation, itTlxingjig (a rigid body)
was disposed on each of the holes 42a, 42b, 43a, 43b, 44a, 44b, 45a, and 45b, and the
base metal member 14 was fixed. Then, a columnar member (a rigid body)
penetrated through the holes 41a and 41b, the plate-like section 121 (the joined metal
member 12) was pulled in a direction perpendicular to the front surface 14a of the
plate-like section 141 by a force of2.0 kN through the member.
[0082]
The configuration of both of the third model and the fourth model was defined
as described below. Furthermore, as described above, in the third model, the position
of the weld overlay sections 30a and 30b in the front-rear direction was variously
changed.
[0083]
(Configuration of Analysis Model)
· Joined Metal Member
Material: Steel
Thickness: 2.6 mm
- 49 -
Height (Length in First Direction Dl): 80 mm
Length in Right-Left Direction (Second Direction D2): 70 mm
Length in Front-Rear Direction (refer to FIG. 9): 80 mm
Position of Hole 4la: Center of Side Wall Section 12la
Position of Hole 41 b: Center of Side Wall Section 121 b
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
· Base Metal Member
Material: Steel
Thickness: 2.0 mm ' '• ' ·, •, • ~ -:t i·r- -:· · --- '{· ·
Height (Length in First Direction Dl): 50 mm
Length in Right-Left Direction (Second Direction D2): 300 mm
Length in Front-Rear Direction (refer to FIG. 9): !50 mm
Center-to-Center Distance between Holes 42a and 42b: 230 mm
Center-to-Center Distance between Holes 43a and 43b: 230 mm
Center-to-Center Distance between Holes 44a and 44b: 230 nm1
Center-to-Center Distance between Holes 45a and 45b: 230 mm
Center-to-Center Distance between Holes 42a and 43a: 100 mm
Center-to-Center Distance between Holes 42b and 43b: 100 mm
Distance in Vertical Direction from Front Surface 14a to Center of
Holes 44a, 44b, 45a, and 45b: 25 mm
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
·Weld Bead
Width (Width of Section Excluding Section Protruding from
- 50 -
Abutting End Sections 32a and 32b (refer to FIG. 9) to Front): 4.3 mm
Height (Height of Section Excluding Section Protruding from
Abutting End Sections 32a and 32b to Front): 5.0 mm
Width (Width of Section Protruding from Abutting End Sections 32a
and 32b to Front): 10.6 mm
Height (Height of Section Protruding from Abutting End Sections
32a and 32b to Front): 2.2 mm
Protrusion Amount (Distance Lw) from Abutting End Sections 32a
and 32b: 13.7 mm
Young's Modulus: 2!0,000 MPa
Poisson's Ratio: 0.3
· Weld Overlay Section (Third Model)
Width: 6.0 mm
Height 2.0 mm
Length: 6.0 mm, 10.0 mm, 12.0 mm, 14.0 mm, 16.0 mm, 20.0 mm,
24.0 mm, and 28.0 mm
Position of Weld Overlay Section 30a in Right-Left Direction: Center
Line of Weld Overlay Section 30a is Coincident with Left Edge of Abutting Side
Surface 322a (refer to FIG. 9)
Position of Weld Overlay Section 30b in Right-Left Direction: Center
Line of Weld Overlay Section 30b is Coincident with Right Edge of Abutting Side
Surface 322b (refer to FIG. 9)
[0084]
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
- 51 -
Furthermore, in a case where the analysis is performed in consideration of the
yield of the material of the joined metal member 12 and the base metal member 14 and
in a case where the analysis is performed without consideration of the yield, a
magnitude relationship between a stress generated in the third model and a stress
generated in the fourth model is not changed. Therefore, in a case where a magnitude
. relationship between the maximum main stress generated in the third model and the
maximum main stress generated in the fourth model is relatively evaluated, the
presence or absence of the yield of the material may not be considered. Therefore, in
this simulation, in order to simplifY the analysis, elastic property analysis was
performed withourconsideration uf!hc yieiu of the material ofthej'6ined m~tat"•·'·· ·
member 12 and the base metal member 14. In addition, in a case where the
magnitude relationship between the maximum main stresses is relatively evaluated as
described above, the yield of the material may not be considered, and thus, it is
possible to evaluate the welded structure member including the joined metal member
12 and the base metal member 14 having an arbitrary tensile strength by this
simulation. That is, for example, it is possible to evaluate a welded structure member
using a material having a tensile strength of270 MPa, and to evaluate a welded
structure member using a material having a tensile strength of I ,500 MPa, by this
simulation.
[0085]
In FIG. 15A, a relationship between the front end position of the weld overlay
section 30a and a maximum value of the maximum main stress which is generated in
the vicinity of the weld bead end section 24a at each length of the weld overlay section
30a (refer to FIG. 9) is illustrated. Furthermore, the front end position of the weld
overlay section 30a indicates the position of the front end of the weld overlay section
- 52 -
.. ,,
30a in the front-rear direction in a case of being on the basis of the weld bead end
section 24a (refer to FIG. 9). In FIG. IS A, in a case where the front end of the weld
overlay section 30a is positioned on the front from the weld bead end section 24a, the
front end position of the weld overlay section 30a is represented by a positive value,
and in a case where the front end of the weld overlay section 30a is positioned on the
rear from the weld bead end section 24a, the front end position of the weld overlay
section 30a is represented by a negative value. For example, in the welded structure
member lOB illustrated in FIG. 9, the front end of the weld overlay section 30a is
positioned on the front from the weld bead end section 24a, and thus, the front end
·position ofthe weld overiay sectiOn JOa is represented·bya'positive value,:· ·In'; ·· r ,. '
addition, in FIG. I SA, the maximum value (1,273 MPa) of the maximum main stress in
the analysis model not including the weld overlay sections 30a and 30b is illustrated by
a broken line. Furthermore, even though the description is omitted, a relationship
between the front end position of the weld overlay section 30b and a maximum value
of the maximum main stress which is generated in the vicinity of the weld bead end
section 24b also became the same relationship as that illustrated in FIG. I SA.
[0086]
In FIG. 15B, a relationship between the rear end position of the weld overlay
section 30a and the maximum value of the maximum main stress which is generated in
the vicinity of the weld bead end section 24a at each length of the weld overlay section
30a (refer to FIG. 9) is illustrated. Furthermore, the rear end position of the weld
overlay section 30a indicates the position of the rear end of the weld overlay section
30a in the front-rear direction in a case of being on the basis of the weld bead end
section24a (refer to FIG. 9). In FIG. 15B, in a case where the rear end of the weld
overlay section 30a is positioned on the front from the weld bead end section 24a, the
- 53 -
rear end position of the weld overlay section 30a is represented by a positive value, and
in a case where the rear end of the weld overlay section 30a is positioned on the rear
from the weld bead end section 24a, the rear end position of the weld overlay section
30a is represented by a negative value. For example, in the welded structure member
lOB illustrated in FIG. 9, the rear end of the weld overlay section 30a is positioned on
the rear from the weld bead end section 24a, and thus, the rear end position of the weld
overlay section 30a is represented by a negative value. In addition, as with FIG. !SA,
in FIG. 15B, the maximum value (1,273 MPa) of the maximum main stress in the
analysis model not including the weld overlay sections 30a and 30b is illustrated by a
·· , bwken·iinc. fwthermorc, even though the dcscripti'on is,6J11itted,:.a relationshipi··''
between the rear end position of the weld overlay section 30b and the maximum value
of the maximum main stress which is generated in the vicinity of the weld bead end
section 24b became the same relationship as that illustrated in FIG. IS B.
[0087]
From FIG. 15Aand FIG. 15B, it is known that according to the present
invention, the front end position and the rear end position ofthe weld overlay sections
30a and 30b are suitably set, and thus, it is possible to reduce the maximum value of
the maximum main stress ofthe weld bead end sections 24a and 24b. Specifically,
from FIG. J SA, it is known that even in a case where the length of the weld overlay
sections 30a and 30b is short, which is 6.0 mm, the front end position of the weld
overlay sections 30a and 30b is set to be -1.7 mm to 4.7mm, and thus, it is possible to
reliably reduce the maximum value of the maximum main stress compared to a case
where the weld overlay section does not exist. In addition, it is known that the front
end position of the weld overlay sections 30a and 30b is set to be -0.1 mm to 3.7 mm,
to be preferably 0.5 mm to 3.0 mm, and to be more preferably 1.0 mm to 2.4 mm, and
- 54 -
thus, it is possible to sufficiently reduce the maximum value of the maximum main
stress. In addition, as it is known from FIG. I 58, the rear end position of the weld
overlay sections 30a and 30b was set to be less than or equal to -1.3 mm regardless of
the length of the weld overlay sections 30a and 30b, and thus, it was possible to reduce
the maximum value of the maximum main stress compared to a case where the weld
overlay section did not exist.
[0088]
(Examination 4 based on Simulation)
With reference to FIG. 15A, in the simulation described above, in a case were
'·_, . ".; '· · .. the length of the weld overlay sections 30a and 30b was li(}mn1; the maximutwvalue
of the maximum main stress decreased to 958 MPa when the front end position of the
weld overlay sections 30a and 30b was 1.3 mm. As described above, the maximum
value of the maximum main stress in the analysis model not including the weld overlay
section was 1,273 MPa. Therefore, it is known that the weld overlay sections 30a and
30b are disposed, and thus, the maximum value of the maximum main stress
maximally decreases by 315 MPa. At this time, when a decrease rate of the
maximum value of the maximum main stress (a decrease rate of the maximum value of
the maximum main stress with respect to the analysis model not including the weld
overlay section) was set to 100%, the front end position of the weld overlay sections
30a and 30b at the time that the decrease rate became 30% (a decrease of95 MPa) was
-0.5 mm and 4.1 mm. That is, in a case where the front end position of the weld
overlay sections 30a and 30b is in a range of -0.5 mm to 4.1 mm, it is possible to set
the decrease rate of the maximum value of the maximum main stress (hereinafter,
simply referred to as a ) to be greater than or equal to 30%. That is, a lower limit of
the front end position of the weld overlay sections 30a and 30b for setting the decrease
- 55 -
rate to be greater than or equal to 30% is -0.5 mm, and an upper limit thereof is 4.1
mm.
[0089]
Similarly, in a case where the length of the weld overlay sections 30a and 30b
is 10.0 mm, the maximum value ofthe maximum main stress when the front end
position of the weld overlay sections 30a and 30b was 2.3 mm decreased to 940 MPa.
As described above, the maximum value ofthe maximum main stress in the analysis
model not including the weld overlay section was 1,273 MPa. Therefore, it is known
that the weld overlay sections 30a and 30b are disposed, and thus, the maximum value
• ': · .• < •;·y· • • '\.>f\l1e maximum t11ain stress maximally dtcrtascs' by'333 'MPi( · At this tinic;·when
the decrease rate was set to 100%, the front end position of the weld overlay sections
30a and 30b at tbe time tl1at fue decrease rate became 30% (a decrease of 100 MPa)
was -0.3 mm and 7.6mm. That is, the lower limit of the front end position of the
weld overlay sections 30a and 30b for setting the decrease rate to be greater than or
equal to 30% is -0.3 mm, and the upper limit thereof is 7.6mm.
[0090]
Even though the detailed description is omitted, in a case where the length of
the weld overlay sections 30a and 30b was 12.0 mm, 14.0 mm, 16.0 mm, 20.0 mm,
24.0 mm, and 28.0 mm, the same examination was also performed with respect to the
position of the weld overlay sections 30a and 30b for setting the decrease rate to be
greater than or equal to 50%, to be greater than or equal to 75%, and to be greater than
or equal to 90%. Further, in the third model described above, the thickness of the
base metal member 14 was set to 2.3 mm, 1.6 mm, and I .2 mm, and the same
simulation as that described above was performed. Then, the same examination was
performed with respect to a relationship between the decrease rate and the weld
- 56 -
overlay sections 30a and 30b. Furthermore, even in a case where the thickness of the
base metal member 14 is 2.3 mm, 1.6 mm, and 1.2 mm, the length of the weld overlay
sections30aand30bwassetto6.0mm, lO.Omm, 12.0mm, 14.0mm, 16.0mm,20.0
mm, 24.0 mm, and 28.0 mm. Examination results thereof are shown in FIG. 16A to
FIG. 190 along with examination results in a case where the thickness of the base
metal member 14 is 2.0 mm.
[0091]
As it is known from FIG. 16A, in a case where the lower limit of the front end
position of the weld overlay sections 30a and 30b is greater than or equal to -0.1 mm, it
' ·'' · '' ··. · Is possible to set-the deorcaseE:ie to be at least Jll%'reganlless ofthe· thickiTessofthe
base metal member 14 and the length of the weld overlay sections 30a and 30b. In
other words, (C) the front end of the weld overlay sections 30a and 30b is positioned
on the front from a position which is separated from the weld bead end sections 24a
and 24b (refer to FIG. 9) to the rear by 0.1 mm, and thus, the decrease rate of at least
30% can be realized. In addition, from FIG. 16B to FIG. 160, it was known that it
was preferable that the front end of the weld overlay sections 30a and 30b was
positioned on the front from a position which was separated from the weld bead end
sections 24a and 24b to the front by 0.3 mm, it was more preferable that the front end
of the weld overlay sections 30a and 30b was positioned on the front from a position
which was separated from the weld bead end sections 24a and 24b to the front by 1.2
mm, and it was even more preferable that the front end of the weld overlay sections
30a and 30b was positioned on the front from a position which was separated from the
weld bead end sections 24a and 24b to the front by 1.9 mm.
[0092]
As it is known from FIG. 17 A, an upper limit ofthe front end position of the
- 57 -
weld overlay sections 30a and 30b at the time that the decrease rate became 30%
increased according to an increase in the length of the weld overlay sections 30a and
30b. As illustrated in FIG. 17B, such a relationship was also confirmed in a case
where the decrease rate was 50%. In contrast, as illustrated in FIG. 17C and FIG.
17D, in a case where the decrease rate was 75% and 90%, the upper limit of the front
end position of the weld overlay sections 30a and 30b did not greatly increase even in a
case where the length of the weld overlay sections 30a and 30b increased.
Specifically, in a case where the upper limit of the front end position of the weld
overlay sections 30a and JOb was less than or equal to 2.3 mm, it was possible to set
· the decrease rate to he· at least ')0'?-o regardless ofthe length 'Ofthe Weld overlay•·:"·· ' · ·
sections 30a and 30b.
[0093]
As it is known from FIG. 18A, a lower limit ofthe rear end position of the
weld overlay sections 30a and 30b at the time that the decrease rate became 30%
decreased according to an increase in the length of the weld overlay sections 30a and
30b. As illustrated in FIG. 18B to FIG. 18D, such a relationship was also confirmed
in a case where the decrease rate was 50%, 75%, and 90%.
As it is known from FIG. 19Aand FIG. 19B, the upper limit of the rear end
position of the weld overlay sections 30a and 30b at the time that the decrease rate
became 30% or 50% was approximately constant. In contrast, as it is known from
FIG. 19C and FIG. 19D, the upper limit of the rear end position ofthe weld overlay
sections 30a and 30b at the time that the decrease rate became 75% or 90% decreased
according to an increase in the length of the weld overlay sections 30a and 30b.
[0094]
Furthermore, as it is known from FIG. 19A, in a case where the upper limit of
- 58 -
the rear end position of the weld overlay sections 30a and 30b is less than or equal to-
3.0 mm, it is possible to set the decrease rate to be at least 30% regardless of the plate
thickness of the base metal member 14 and the length of the weld overlay sections 30a
and 30b. In other words, (D) the rear end of the weld overlay sections 30a and 30b is
positioned on the rear from a position which is separated from the weld bead end
sections 24a and 24b to the rear by 3.0 mm, and thus, the decrease rate of at least 30%
can be realized. Accordingly, it is possible to sufficiently reduce the maximum value
of the maximum main stress which is generated in the vicinity of the weld bead end
sections 24a and 24b, and thus, even in a case where the thickness of the base metal
•· : ,.· member ·14 cte·cicases; ·ii-'ls'possible to sufficiently ensure the fatigoe stren~ln1Ptlfe·
welded structure member 10.
[0095]
In consideration of (C) and (D) described above, in order to more reliably
realize the decrease rate of greater than or equal to 30%, it is preferable that the weld
overlay sections 30a and 30b are disposed over a position which is separated at least
from the at least weld bead end section to the rear by 0.1 mm to 3.0 mm.
[0096]
In addition, in consideration of 90% at which an improvement rate is further
improved, as illustrated in FIG. 16D and FIG. 17D, both of the upper limit and the
lower limit of the front end position of the weld overlay section are positive values.
In addition, as illustrated in FIG. lSD and FIG. 190, both of the upper limit and the
lower limit of the rear end position of the weld overlay section are negative values.
From this, in order for better improvement, it is preferable that the weld overlay
sections 30a and 30b are disposed to cross the weld bead end sections 24a and 24b.
[0097]
- 59 -
.. ~-· .
(Examination 5 based on Simulation)
Hereinafter, a relationship between the maximum main stress which is
generated in the vicinity of the abutting end sections 32a and 32b and the maximum
main stress which is generated in the vicinity of weld bead end sections 24a and 24b in
a case where the plate thickness of the base metal member 14 is changed will be
described in detail along with a simulation result using a computer. In this
simulation, an analysis model(hereinafter, also referred to as a.fifth m0del) which had
the same configuration as that of the welded structure member lOA illustrated in FIG 1
to FIG 4 but not included the weld overlay sections 30a and 30b was prepared, and the
··max\ !hum 'm<1in stress whichwas generated in the vicinity'oTthe·aimHing end sections
32a and 32b and the maximum main stress which was generated in the vicinity of the
weld bead end sections 24a and 24b were obtained.
[0098]
Furthermore, in the fifth model, holes were formed in positions illustrated by
the dotted circles 41a, 4lb, 42a, 42b, 43a, 43b, 44a, 44b, 45a, and 45b in FIG 1 and
FIG 2 (hereinafter, each of the holes illustrated by the dotted line will be referred to as
a hole). In the simulation, a fixing jig (a rigid body) was disposed on each of the
holes 42a, 42b, 43a, 43b, 44a, 44b, 45a, and 45b, and the base metal member 14 was
fixed. Then, a columnar member (a rigid body) penetrated through the holes 41a and
41b, the plate-like section 121 (the joined metal member 12) was pulled in a direction
perpendicular to the front surface 14a of the plate-like section 141 by a force of2.0 kN
through the member.
[0099]
The configuration of the fifth model was defined as described below.
Furthermore, as described above, plate thickness of the base metal member 14 was
- 60 -
-.-.,-· ..
variously changed.
3.5 mm
[01 00]
(Configuration of Analysis Model)
· Joined Metal Member
Material: Steel
Thickness: 2.6 mm
Height (Length in First Direction 01): 80 mm
Length in Right-Left Direction (Second Direction D2): 70 mm
Length in Front-Rear Direction (refer to FIG. 9): 80 mm
. Pos1tion of Hole 4la: Center ofSide·Wal"l Settioirol-2l·a' •.· ;- •·
Position of Hole 4lb: Center of Side Wall Section 12lb
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
· Base Metal Member
Material: Steel
Thickness: 1.2 mm, 1.6 mm, 2.0 mm, 2.3 mm, 2.6 mm, 3.0 mm, and
Height (Length in First Direction D I): 50 m111
Length in Right-Left Direction (Second Direction D2): 300 111m
Length in Front-Rear Direction (refer to FIG. 9): !50 mm
Center-to-Center Distance between Holes 42a and 42b: 230 111m
Center-to-Center Distance between Holes 43a and 43b: 230 mm
Center-to-Center Distance between Holes 44a and 44b: 230 mm
Center-to-Center Distance between Holes 45a and 45b: 230 mm
Center-to-Center Distance between Holes 42a and 43a: 100 mm
- 61 -
·- •. -_ 1.Center-to-Center Distance between Holes 42b and 43b: l 00 mm
Distance in Vertical Direction from Front Surface 14a to Center of
Holes 44a, 44b, 45a, and 45b: 25 mm
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
·Weld Bead
Width (Width of Section Excluding Section Protruding from
Abutting End Sections 32a and 32b (refer to FIG 9) to Front): 4.3 mm
Height (Height of Section Excluding Section Protruding from
Abutting End Sections 32a and 31.b to Front): :J.O mm '' ·· · ·
Width (Width of Section Protruding from Abutting End Sections 32a
and 32b to Front): 10.6 mm
Height (Height of Section Protruding from Abutting End Sections
32a and 32b to Front): 2.2 mm
Protrusion Amount (Distance Lw) from Abutting End Sections 32a
and 32b: 10.4 mm, 13.7 nm1, 17.0 mm, and 20.0 mm
Young's Modulus: 210,000 MPa
Poisson's Ratio: 0.3
[0101]
In a case where the protrusion amount (the distance Lw) from the abutting end
sections 32a and 32b of the weld bead is 10.4 mm, 13.7 mm, 17.0 mm, and 20.0 mm ..
the results of simulating the maximum main stress which is generated in the vicinity of
the abutting end sections 32a and 32b and the maximum main stress which is generated
in the vicinity of the weld bead end sections 24a and 24b at the time of changing the
plate thickness ofthe base metal member 14 are shown in FIG. 20, FIG. 21, FIG. 22,
- 62 -
'· ', ,-, ') .--, ,, ·' .-
and FIG 23. It was known that a magnitude relationship between the maximum main
stress which was generated in .the vicinity of the abutting end sections 32a and 32b and
the maximum main stress which was generated in the vicinity of the weld bead end
sections 24a and 24b was correlated to the plate thickness and the protrusion amount
(the distance Lw) from the abutting end sections 32a and 32b of the weld bead.
Further, a relationship between the plate thickness of the base metal member 14 at
which the maximum main stress which is generated in the vicinity of the abutting end
sections 32a and 32b is coincident with the maximum main stress which is generated in
the vicinity of the weld bead end sections 24a and 24b and the protrusion amount (the
·:·cJislanceLw) fronl. the' auinting end sections 32a ah'd32bofthe \veld bea<.Fis showi'l'in
FIG 24. From FIG 24, it was known that conditions where the maximum main stress
which was generated in the vicinity of the abutting end sections 32a and 32b was
coincident with the maximum main stress which was generated in the vicinity ofthc
weld bead end sections 24a and 24b could satisfY Expression (C) described below of
the plate thiclmess T (mm) of the base metal member 14.
-0.125Lw + 4.06 mm = T mm ... Expression (C)
From the results, it was known that in a case where a right member of
Expression (C) was larger than a left member of Expression (C), the maximum main
stress which was generated in the vicinity of the abutting end sections 32a and 32b was
larger than the maximum main stress which was generated in the vicinity of the weld
bead end sections 24a and 24b, and it was preferable that the weld overlay sections 30a
and 30b were disposed in the vicinity of the abutting end sections 32a and 32b. In
addition, it was known that in a case where the right member of Expression (C) was
smaller than the left member of Expression (C), the maximum main stress which was
generated in the vicinity of the weld bead end sections 24a and 24b was larger than the
- 63 -
maximum main stress which was generated in the vicinity of the abutting end sections
32a and 32b, and it was preferable that the weld overlay sections 30a and 30b were
disposed in the vicinity of the weld bead end sections 24a and 24b.
[0102]
In particular, in a case where the value of the left member of Expression (C)
described above is close to the value of the right member of Expression (C) described
above, it is preferable that the weld overlay sections 30a and 30b are disposed in the
vicinity of both of the weld bead end sections 24a and 24b and the abutting end
sections 32a and 32b, and as a result of disposing the weld overlay section in the
vicinity of the abutting·end·sections Jla and 32b where the maximum main:stress is '.
large even in a case where the value of the right member of Expression (C) described
above is larger than the value of the left member of Expression (C) described above,
the maximum main stress in the vicinity of the weld bead end sections 24a and 24b
increases, and a reduction in the maximum main stress in the vicinity of the abutting
end sections 32a and 32b becomes a countermeasure against improvement of the
fatigue strength.
[Industrial Applicability]
[01 03]
According to the present invention, it is possible to provide a configuration in
which a fatigue strength can be easily improved in a welded structure member
including aT-shaped joint portion.
[Brief Description of the Reference Symbols]
[0104]
lOA, lOA', JOB: WELDED STRUCTURE MEMBER
12: JOINED METAL MEMBER
- 64 -
121: PLATE-LIKE SECTION
12la, 121b: SIDE WALL SECTION
12lc: BOTTOM WALL SECTION
14: BASE METAL MEMBER
14a: FRONT SURFACE (FIRST SURFACE)
14b: REAR SURFACE (SECOND SURFACE)
141: PLATE-LIKE SECTION
14la, 141b: SIDE WALL SECTION
141c: TOP PLATE SECTION
24: WELD BEAD ~- ' ' . ~-...
24a, 24b: WELD BEAD END SECTION
24la, 24lb: SIDE WALL BEAD SECTION
241 c: BOTTOM WALL BEAD SECTION
30a, 30b: WELD OVERLAY SECTION
32: ABUTTING SURFACE
32a, 32b: ABUTTING END SECTION
322a, 322b: ABUTTING SIDE SURFACE
322c: ABUTTING BOTTOM SURFACE

[Document Type] CLAIMS
I. A welded structure member, comprising:
a base metal member including a first surface and a second surface which are
both surfaces each other;
a joined metal member including an abutting surface of which an end surface
abuts onto the first surface;
a weld bead which .is formed on the first surface, and joins the joined metal
member to the base metal member; and
a weld overlay section which is formed on the second surface of the base
melal member, and is li:nmed mto a shape of a line such thi\t' the\vet'd"overhiy:Section
overlaps at least one of the abutting surface and the weld bead, in the view of facing
the second surface and of penetrating through the base metal member,
wherein when a direction from an abutting end section which is an end section
ofthe abutting surface towards a direction in which the abutting surface exists is set to
the rear, and the opposite direction thereof is set to the front, the weld bead includes a
weld bead end section in a position which is separated to the front of the abutting end
section.
2. The welded structure member according to claim 1,
wherein the weld overlay section is disposed over a position which is
separated from the abutting end section to the rear by 1.9 mm to 7.0 mm, in the view of
facing the second surface and of penetrating through the base metal member.
3. The welded structure member according to claim 2,
wherein a front end of the weld overlay section is positioned from the abutting
- 66 -
end section to the front, and a rear end of the weld overlay section is positioned from
the abutting end section to the rear, in the view of facing the second surface and of
penetrating through the base metal member.
4. The welded structure member according to claim 2 or 3,
wherein the weld overlay section is parallel to the abutting surface, in the
view of facing the second surface and of penetrating through the base metal member.
5. The welded structure member according to any one of claims 2 to 4,
.. , ' wherein a S<;Jpiuatimr!dislance Lw (mm) bet'weewthhlbUttingieiJ:d'-sedtiotr·allt.l
the weld bead end section, and a plate thickness T (mm) of the base metal member
satiszy Expression (A) described below.
mm.
-0.125Lw + 4.06 mm :S: T :S: 4.5 mm ... Expression (A)
6. The welded structure member according to any one of claims 2 to 5,
wherein a length of the weld overlay section is greater than or equal to 10.0
7. The welded structure member according to claim 1,
wherein the weld overlay section is disposed over a position which is
separated from the weld bead end section to the rear by 0.1 mm to 3.0 mm, in the view
of facing the second surface and of penetrating through the base metal member.
8. The welded structure member according to claim 7,
wherein a front end of the weld overlay section is positioned ftom the weld
- 67 -
bead end section to the front, and a rear end of the weld overlay section is positioned
from the weld bead end section to the rear, in the view of facing the second surface and
of penetrating through the base metal member.
9. The welded structure member according to claim 7 or 8,
wherein the weld overlay section is parallel to the weld bead, in the view of
facing the second surface and of penetrating through the base metal member ..
10. The welded structure member according to any one of claims 7 to 9,
, ... wherein a sepamtion:distance Lw ~rnrn) betweeh ihiJ,abutting·end's.ectidit:'and
the weld bead end section, and a plate thickness T (mm) ofthe base metal member
satiszy Expression (B) described below.
mm.
0.8 mm :S T < -0.125Lw + 4.06 mm ... Expression (B)
II. The welded structure member according to any one of claims 7 to I 0,
wherein a length of the weld overlay section is greater than or equal to 6.0
12. The welded structure member according to any one of claims 1 to 11,
wherein a height of the weld overlay section from the second surface is 2.0
mm to 20.0 mm.
13. The welded structure member according to any one of claims 1 to 12,
wherein the weld overlay section is a weld overlay bead which is not involved
in the joint between the base metal member and the other member.
- 68 -
14. The welded structure member according to any one of claims 1 to 13,
wherein the weld overlay section is formed to enter the base metal member.
15. The welded structure member according to any one of claims 1 to 14,
wherein the weld. bead does not penetrate through the base metal member.
16. The welded stmcture member according to any one of claims 1 to 15,
wherein the base metal member is a steel sheet having a tensile strength of
greater than ur eyual to 270 Mi'a. ,,. >
17. A method of manufacturing the welded structure member according to
any one of claims 1 to 16, the method comprising:
a weld. bead applying step of applying a weld bead which joins the first
surface of the base metal member to the end surface of the joined metal member by the
abutting surface; and
a weld overlay section applying step of applying the weld overlay section onto
the second surface of the base metal member by arc welding or brazing, before the
weld bead applying step or after the weld bead applying step.
Dated tlus 29th day of March, 2017
[AANJNA JVIEHTA DDiTJ
. [IN/FA- 190A]
OF REMFRY AND SAGAR
ATTORNEY FORTI-IE APPLICANT(S)
- 69 -
[Document Type] Abstract
This welded structure member includes a base metal member including a ilrst
surface and a second surface; a joined metal member including an abutting surface of
which an end surface abuts onto the first surface; a weld bead which is formed on the
first surface; and a weld overlay section which is formed on the second surface ofthe
base metal member, in which the weld bead includes a weld bead end section in a
position which is separated to the front of the abutting end section.