WO2018061526A1 - Method of manufacturing laser welded joint, laser welded joint, and automotive frame component - Google Patents

Method of manufacturing laser welded joint, laser welded joint, and automotive frame component Download PDF

Info

Publication number
WO2018061526A1
WO2018061526A1 PCT/JP2017/029899 JP2017029899W WO2018061526A1 WO 2018061526 A1 WO2018061526 A1 WO 2018061526A1 JP 2017029899 W JP2017029899 W JP 2017029899W WO 2018061526 A1 WO2018061526 A1 WO 2018061526A1
Authority
WO
WIPO (PCT)
Prior art keywords
bead
welding
less
laser
welded joint
Prior art date
Application number
PCT/JP2017/029899
Other languages
French (fr)
Japanese (ja)
Inventor
亜怜 原
木谷　靖
Original Assignee
Ｊｆｅスチール株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to CN202011472962.9A priority Critical patent/CN112743228B/en
Priority to KR1020207033067A priority patent/KR102412797B1/en
Priority to KR1020217024757A priority patent/KR102425207B1/en
Priority to KR1020197004575A priority patent/KR102184912B1/en
Priority to JP2017562099A priority patent/JP6662396B2/en
Priority to CN201780050173.6A priority patent/CN109641321B/en
Publication of WO2018061526A1 publication Critical patent/WO2018061526A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B23K26/24—Seam welding
    • B23K26/244—Overlap seam welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/32—Bonding taking account of the properties of the material involved
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D25/00—Superstructure or monocoque structure sub-units; Parts or details thereof not otherwise provided for
    • B62D25/04—Door pillars ; windshield pillars
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese

Definitions

  • the present invention relates to a method for manufacturing a laser welded joint, a laser welded joint, and an automobile frame part.
  • resistance spot welding is used for welding structural members of automobiles.
  • resistance spot welding has a problem that it takes a long time to weld, a problem that the pitch cannot be narrowed due to a diversion, and a problem that there is a spatial restriction due to the gun of the welding machine.
  • studies have been made on laser welding in which the steel plates are joined by irradiating the surface of the superposed steel plates with a laser beam.
  • laser welding a laser beam is irradiated on the surface of the stacked steel plates to melt and solidify the laser beam irradiated portion of the steel plates, thereby forming beads and joining the steel plates to obtain a laser welded joint.
  • Patent Document 1 is a method of welding from the smaller gap between the plates to the larger one.
  • a special clamping jig is required and only a predetermined welding path can be welded. There is a problem. In addition, the appearance has not been studied.
  • Patent Document 2 is a method of improving the appearance of welding by wrapping the welding line and remelting the welding start / end portion, but there is a problem that welding takes time and is difficult to use.
  • the problem that the bead end portion is cracked and the appearance is deteriorated is not limited to the structural member of the automobile, but also exists in laser welded joints used for other purposes.
  • the present invention has been made in view of such circumstances, and provides a laser welded joint manufacturing method, a laser welded joint, and an automobile skeleton component that are excellent in appearance by suppressing the occurrence of cracks at a bead end portion. Objective.
  • the present inventors control the thickness of the two steel plates, the size of the gap between the two steel plates, the laser output, and the relationship thereof, that is, the following equation (1): It was found that the occurrence of cracks on the bead end side can be suppressed by satisfying the requirements, and the present invention has been completed.
  • a is less than the smaller of the 0.5 t 1 and 0.5t 2
  • K (t 2 / t 1)
  • a ( unit: mm) is.
  • the thickness of the upper steel plate is t 1 (mm)
  • the thickness of the lower steel plate is t 2 (mm)
  • the size of the gap between the upper steel plate and the lower steel plate is a (mm)
  • initial The laser output in welding and main welding is P (kW)
  • the laser output in final welding is P f (kW).
  • the melted portion is made small at the end of welding, and the melted portion is stabilized so that no welding defect occurs during solidification. As a result, the occurrence of cracks at the end of the bead is prevented.
  • the beat width may become narrow at the welding start end (bead start end).
  • heat input must be increased to melt the steel plate surface. That is, since energy is required to melt the steel sheet surface, welding is not stable. As a result, it was found that the beat width at the beginning of the bead became narrow.
  • a method of increasing the heat input a method of increasing the laser output at the start of welding and a method of decreasing the welding speed are conceivable.
  • an increase in the amount of spatter can be considered as a method for increasing the laser output. Therefore, paying attention to the method of lowering the welding speed at the start of welding, we studied to prevent the bead width at the bead start end from becoming narrow. Furthermore, it is necessary to consider energy loss when there is a gap between the stacked steel sheets.
  • the thickness of the upper steel plate is t 1 (mm)
  • the thickness of the lower steel plate is t 2 (mm)
  • the size of the gap between the upper steel plate and the lower steel plate is a (mm)
  • this The welding speed in welding and final welding is v (m / min)
  • the welding speed in initial welding is vi (m / min).
  • the present invention has been completed based on the above findings, and the gist thereof is as follows.
  • a laser beam is irradiated on the upper steel plate surface with two steel plates stacked vertically so as to have a gap between them, and a portion irradiated with the laser beam is melted and solidified to form a bead.
  • a method of manufacturing a laser welded joint for obtaining a laser welded joint in which two steel plates are joined by laser welding for joining two steel plates together The plate thickness of the upper steel plate is t 1 (mm), the plate thickness of the lower steel plate is t 2 (mm), the size of the gap between the upper steel plate and the lower steel plate is a (mm),
  • Initial welding is the process of forming a bead from the beginning of the bead to the vicinity of 1/5 of the total length of the bead.
  • the initial welding is followed by the process of forming the bead to the vicinity of 4/5 of the total length of the bead.
  • the process of forming the bead to the end is the final welding,
  • the laser output in the initial welding and the main welding is P (kW)
  • the laser output in the final welding is P f (kW)
  • the manufacturing method of the laser welded joint characterized by satisfy
  • the position of 1/10 of the total length of the bead from the end of the bead is 1/10 part of the bead end
  • the bead width of the bead body is W
  • the bead width at the bead end 1/10 part is W f
  • the position of 1/10 of the total beat length from the bead start end is 1/10 part of the bead start end.
  • a bead width at the bead beginning 1/10 parts when the W i
  • the laser weld joint according to [3], which satisfies the following formula (4).
  • the two steel sheets are each in mass%, C: more than 0.07% and 0.25% or less, P + S: less than 0.03%, Mn: 1.8% or more and 3.0% or less, Si: More than 1.2% and not more than 1.8%, containing at least one of the following group A and group B, with the balance being composed of Fe and inevitable impurities, with a plate thickness of 1. It is 0 mm or more and 2.0 mm or less,
  • the frame part for motor vehicles described in [5] characterized by the above-mentioned.
  • Group A Ti: 0.005% or more and 0.01% or less and Nb: 0.005% or more and less than 0.050%
  • Group B Cr: 1.0% or less
  • Mo 0.50% or less
  • B At least one selected from 0.10% or less
  • a laser welded joint having an excellent appearance can be manufactured. Moreover, since generation
  • the bead width can be made uniform over the entire bead, and a laser welded joint with a better appearance can be manufactured.
  • the laser welded joint of the present invention is excellent in appearance, it can be suitably used for a structural member of an automobile.
  • a high-strength steel sheet can be used as a steel sheet to be joined to form a skeletal part for an automobile.
  • the method of manufacturing a laser welded joint according to the present invention melts a portion irradiated with a laser beam by irradiating the surface of the upper steel plate with two steel plates stacked vertically with a gap between them.
  • a laser weld joint in which two steel plates are joined is obtained by laser welding that solidifies and forms a bead and joins two steel plates.
  • the plate thickness of the upper steel plate is t 1 (mm)
  • the plate thickness of the lower steel plate is t 2 (mm)
  • the size of the gap between the upper steel plate and the lower steel plate is a (mm)
  • Initial welding is the process of forming a bead from the beginning of the bead to the vicinity of 1/5 of the total length of the bead.
  • the initial welding is followed by the process of forming the bead to the vicinity of 4/5 of the total length of the bead.
  • the process of forming the bead to the end is the final welding
  • the laser output in the initial welding and the main welding is P (kW)
  • the laser output in the final welding is P f (kW)
  • the following equation (1) It is characterized by satisfying.
  • FIG.1 (a) is a perspective view which shows the external appearance of the laser welded joint of this invention manufactured with the manufacturing method of the laser welded joint of this invention
  • FIG.1 (b) is the principal part of FIG.1 (a). It is an enlarged view.
  • FIG. 2 is an enlarged cross-sectional view of a laser welded joint manufactured by the laser welded joint manufacturing method of the present invention.
  • FIG. 3 is a top view showing a bead formed on the surface of the upper steel plate of the laser welded joint manufactured by the laser welded joint manufacturing method of the present invention.
  • a hat-shaped steel plate (hat portion upper plate) 4 and a steel plate (hat portion lower plate) 5 are used. , And overlap each other so that there is a gap between them.
  • the object to be laser welded is a steel plate (steel plate 4, steel plate 5).
  • the kind of the steel plate 4 and the steel plate 5 is not specifically limited, For example, it is preferable that it is a high strength steel plate with a tensile strength of 980 MPa or more.
  • a high-strength steel sheet of 980 MPa or more is likely to crack on the bead end side because the carbon equivalent is relatively high.
  • the method for producing a laser welded joint according to the present invention the occurrence of cracks on the bead end side can be suppressed, and even when a high-strength steel plate is used, the occurrence of cracks is suppressed and a laser welded joint having an excellent appearance can be produced.
  • a laser-welded joint of a high-strength steel plate having a tensile strength of 980 MPa or more it can be suitably used as an automobile skeleton member that requires strength.
  • the component composition of the steel plate 4 and the steel plate 5 is not specifically limited, For example, by mass%, C: more than 0.07% and 0.25% or less, P + S: less than 0.03%, Mn: 1.8% or more 3. It shall contain 0% or less, Si: more than 1.2% and 1.8% or less, at least one of the following group A and group B, and a component composition consisting of the remainder Fe and inevitable impurities Can do.
  • % in each component composition refers to mass%.
  • Group A Ti: 0.005% or more and 0.01% or less and Nb: 0.005% or more and less than 0.050%
  • Group B Cr: 1.0% or less, Mo: 0.50% or less and B: At least one selected from 0.10% or less (C: more than 0.07% and 0.25% or less) If the C content exceeds 0.07%, the effect of precipitation strengthening cannot be obtained. On the other hand, when the C content is 0.25% or less, it is possible to ensure desired high strength and workability without causing precipitation of coarse carbides. Therefore, the C content is preferably 0.07% to 0.25% or less.
  • the total amount (P + S: less than 0.03%) is preferably less than 0.03%.
  • Mn 1.8% to 3.0%
  • the Mn content is preferably 1.8% or more and 3.0% or less.
  • the Mn content is more preferably 2.5% or less.
  • Si 1.2% to 1.8% or less
  • Si content exceeds 1.2%, the effect of increasing the strength of the steel by solid solution is sufficiently obtained.
  • the Si content is 1.8% or less, the hardening of the weld heat affected zone does not increase, and the toughness and the low temperature crack resistance of the weld heat affected zone do not deteriorate.
  • the Si content is preferably 1.2% to 1.8%.
  • the Si content is more preferably 1.5% or less.
  • Ti and Nb are precipitated as carbides or nitrides, and have an action of suppressing austenite coarsening during annealing. Therefore, it is preferable to contain at least one of these elements. In order to obtain this effect, 0.005% or more of Ti and 0.005% or more of Nb are contained. However, even if it contains excessively, the effect by the said effect
  • the Ti content is 0.010% or less, and the Nb content is less than 0.050%.
  • the Ti content is preferably less than 0.008% and the Nb content is preferably less than 0.040%.
  • Cr, Mo, and B are elements having an effect of improving the hardenability of steel. Therefore, you may contain 1 or more types of these elements. However, even if these elements are contained excessively, the above effects are saturated and uneconomical. Therefore, when these elements are contained, the Cr content is 1.0% or less, the Mo content is 0.50% or less, and the B content is 0.10% or less.
  • the Cr content is preferably 0.50% or less, the Mo content is preferably 0.10% or less, and the B content is preferably 0.030% or less.
  • the Cr content is preferably 0.01% or more, the Mo content is preferably 0.004% or more, and the B content is preferably 0.0001% or more.
  • the balance other than the above component composition is Fe and inevitable impurities.
  • Inevitable impurities include Al: 0.015 to 0.050%, N: 0.002 to 0.005%, and the like.
  • the thickness of the two steel plates to be laser welded is not particularly limited, but is preferably in the range of, for example, 1.0 mm or more and 2.0 mm or less. More preferably, they are 1.2 mm or more and 1.8 mm or less.
  • a steel plate having a thickness within this range can be suitably used as an automobile skeleton member.
  • the plate thickness t 1 of the upper steel plate 4 satisfies 1.0 mm ⁇ t 1 ⁇ 2.0 mm
  • the plate thickness t 2 of the lower steel plate 4 satisfies 1.0 mm ⁇ t 2 ⁇ 2.0 mm. It is preferable.
  • the plate thickness t 1 of the upper steel plate 4 satisfies 1.2 mm ⁇ t 1 ⁇ 1.8 mm
  • the plate thickness t 2 of the lower steel plate 4 satisfies 1.2 mm ⁇ t 2 ⁇ 1.8 mm. .
  • the two steel plates 4 and 5 may be the same or different, and the steel plate 4 and the steel plate 5 may be the same type and the same shape, or different types and different shapes. Good.
  • the clearance gap A exists between the steel plate 4 and the steel plate 5 before laser welding.
  • the size a (mm) of the gap A between the steel plate 4 and the steel plate 5 before laser welding that is, the size in the plate thickness direction of the steel plate of the gap A between the steel plate 4 and the steel plate 5 is 0.5 t 1 . It must satisfy the following smaller of 5t 2.
  • the size a of the gap A between the steel plate 4 and the steel plate 5 before laser welding is such that a ⁇ 0 when the plate thickness t 1 of the upper steel plate 4 is smaller than the plate thickness t 2 of the lower steel plate 5.
  • the size a of the gap A when a laser welded joint is manufactured by the method for manufacturing a laser welded joint using a steel plate having a thickness of 1.0 mm or more and 2.0 mm or less that is preferably used as a material for a framework part for an automobile, the size a of the gap A If the thickness is larger than 0.9 mm, meltdown may occur during welding.
  • size a of the clearance gap A between the steel plate 4 and the steel plate 5 before laser welding is over the laser welding direction (the direction in which the laser beam irradiated to the surface of the upper steel plate 4 is moved on the surface of the upper steel plate 4).
  • Laser welding is performed in a state in which the steel plate 4 and the steel plate 5 which are uniform and overlapped with a gap A therebetween are fixed with a restraining jig or the like and the gap A is held.
  • the size of the gap between the steel plate 4 and the steel plate 5 of the laser welded joint obtained by laser welding is the gap A between the steel plate 4 and the steel plate 5 before laser welding.
  • the gap between the steel plate 4 and the steel plate 5 of the laser welded joint of the present invention obtained by the laser welded joint manufacturing method of the present invention is narrower than the size a, for example, the thinner one of the two steel plates 10% to 50%, specifically 0.1 mm or more and 0.9 mm or less, for example.
  • the two steel plates 4 and 5 are overlapped with a gap A therebetween, they are joined by laser welding. Specifically, the surface of the upper steel plate 4 among the superposed steel plates is irradiated with the laser beam 3, and the laser beam 3 is moved relative to the steel plates 4 and 5 in the superposed state. . As a result, the portion irradiated with the laser beam 3 of the steel plate 4 and the steel plate 5 is melted to form a melted portion, and then the melted portion is solidified to form a bead (weld line) 7.
  • this laser welding condition satisfies the above formula (1).
  • the process of forming the bead from the bead starting end X to the vicinity of 1/5 of the total length of the bead is performed to the initial welding S i and the initial welding S i to the vicinity of 4/5 of the total length of the bead.
  • this welding step of forming a bead S, forming a bead to bead end Y Following the welding S and final welding S f, the laser output at the initial weld S i and the welding S and P (kW) In this case, the laser output P f (kW) in the final welding S f satisfies the above formula (1).
  • the vicinity of 1/5 of the total length of the bead is within a range of 1/5 of the total length of the bead ⁇ 3/40 of the total length of the bead, that is, within a range of 5/40 of the total length of the bead to 11/40 of the total length of the bead. Further, the vicinity of 4/5 of the total length of the bead is within the range of 4/5 of the total length of the bead ⁇ 3/40 of the total length of the bead, that is, within the range from 29/40 of the total length of the bead to 35/40 of the total length of the bead.
  • 3 shows an example in which the vicinity of 1/5 of the total length of the bead is set to 1/5 of the total length of the bead, and the vicinity of 4/5 of the total length of the bead is set to 4/5 of the total length of the bead.
  • the total bead length is the length from the bead start to the end in the direction in which the laser beam 3 moves on the surface of the upper steel plate 4.
  • the total bead length is a linear distance between the bead start end X and the bead end Y, and is the length of the bead 7 in the longitudinal direction.
  • the total bead length is on the locus of the laser beam 3 on the surface of the upper steel plate 4. This is the length from the beginning of the bead to the end of the bead.
  • the laser output P f in the welding (final welding S f ) in a specific range near the end of the welding that satisfies the expression (1) is the same as that in the previous welding (the initial welding S i and the main welding S).
  • the bead width can be made uniform.
  • the bead width of the bead main body B and the bead main body B is W
  • the bead end 1/10 part B f is located at 1/10 of the total length of the bead from the bead end Y
  • the bead width at the bead end 1/10 part B f is W
  • the bead body B is a bead formed by the main welding S and is formed by performing stable welding, so that no cracks occur and the bead width W is uniform.
  • the vicinity of the bead start end 1/5 portion, which is 1/5 of the beat total length from the bead start end X, is the bead start end 1/5, which is 1/5 of the beat total length from the bead start end X.
  • Part ⁇ 3/40 of the total bead length that is, within the range of 5/40 of the beat total length from the bead starting end X to 11/40 of the total bead length from the bead starting end X.
  • the vicinity of the bead end 1/5 portion, which is 1/5 of the total bead length from the bead end Y means that the bead end 1/5 portion which is 1/5 of the total bead length from the bead end Y ⁇ the total bead length. It is within the range of 3/40, that is, within the range from 5/40 of the beat total length to the bead end Y to 11/40 of the bead full length from the bead end Y. 0.80 ⁇ W f /W ⁇ 1.20 (3)
  • the formula (1) when the formula (1) is not satisfied, cracks occur on the bead end side, and the bead width becomes thicker or thinner.
  • the laser beam 3 to be irradiated is not particularly limited, and for example, a fiber laser, a disk laser, or the like can be used.
  • the laser beam can be, for example, a beam diameter: 0.2 to 1.0 mm, and a focal position: 30 mm above the surface of the steel plate 4 to the surface of the steel plate 4.
  • the focal position is preferably the surface of the steel plate 4.
  • Initial welding S i and the laser output P in this welding S is, for example, 2.0kW or 5.0kW or less, preferably more than 3.0 kW 4.0 kW.
  • the laser output P is 2.0 kW or more, the laser output is not too low, and through welding is possible.
  • the laser output P is 5.0 kW or less, the laser output does not become too high, so that the molten metal is scattered as spatter and the underfill does not occur in the weld.
  • the laser output P in the initial welding S i and the main welding S is 2.0 kW or more and 5.0 kW or less and P f satisfies the formula (1), it is formed depending on other laser welding conditions. There is no problem that the beat 7 does not penetrate the steel plate 4 or the beads 7 melt.
  • Welding speed v at present welded S and final welding S f is, for example, 1.0 m / min or more 4.0 m / min or less, preferably 2.0 m / min or more 3.0 m / min or less. If the welding speed v is 1.0 m / min or more, the welding speed will not be too slow, so the steel sheet will not melt and become a defect. On the other hand, if v is 4.0 m / min or less, the welding speed will not be too fast, and the molten pool will not become stable.
  • the welding speed v i (m / min) in the initial welding S i is not particularly limited, and may be the same as the welding speed v in the main welding S and the final welding S f , for example, but the welding speed v in the initial welding S 1.
  • i preferably satisfies the following formula (2). 0.75 ((t 1 + t 2 ) / (K + t 1 + t 2)) v ⁇ v i ⁇ ((t 1 + t 2) / (K + t 1 + t 2)) v (2)
  • a is less than the smaller of the 0.5 t 1 and 0.5t 2
  • K (t 2 / t 1) is a.
  • Bead width of the bead start end (bead formed in the initial welding S 1) tend to be thinner than the bead width of the bead body B formed in this welding S, conventionally uniform throughout the bead 7 Those having a bead width were difficult to obtain.
  • the above-described equation (2) is satisfied, that is, the welding speed v i in a specific range of welding (initial welding S i ) near the start of welding is set to the subsequent welding (main welding S and final welding).
  • the bead 7 from the bead starting end X to the vicinity of 1/5 of the total length of the bead tends to be narrower than the bead body B due to the gap A, but the portion where the bead width tends to be narrowed is expressed by the above formula (2 )
  • bead width is set compared with the case where said Formula (2) is satisfy
  • the bead width at the bead beginning 1/10 parts B i W i The following formula (4) can be satisfied. For example, by satisfy
  • the above laser welded joint can be used as a framework component for automobiles. That is, the automotive framework component of the present invention is the laser welded joint of the present invention using high strength steel plates having a tensile strength of 980 MPa or more as the two steel plates 4 and 5 respectively.
  • the automobile frame part of the present invention, as two steel plates 4 and 5, is C: 0.07% to 0.25% or less, P + S: less than 0.03%, Mn: 1.
  • Component composition containing 8% or more and 3.0% or less, Si: more than 1.2% and 1.8% or less, containing at least one of group A and group B, with the balance being Fe and inevitable impurities And having a plate thickness of 1.0 mm or more and 2.0 mm or less (more preferably, 1.2 mm or more and 1.8 mm or less).
  • Such an automobile skeletal component of the present invention can be applied to a center pillar because of its high strength and excellent appearance. In the center pillar, it is important to ensure the peel strength, and the center pillar to which the automobile frame component of the present invention is applied has a sufficient peel strength.
  • steel type I tensile strength is 983 MPa, component composition is mass%, C: 0.13%, Si: 1.40%, Mn: 2.2%, P: 0.015%, S : 0.002%, Ti: 0.005%, Cr: 0.021%, Mo: 0.004%, B: 0.0002%
  • steel type II tensile strength is 1184 MPa, component composition is mass%) C: 0.13%, Si: 1.40%, Mn: 2.2%, P: 0.012%, S: 0.001%, Ti: 0.005%, Cr: 0.017%, Mo : 0.004%, B: 0.0003%
  • a steel plate having a plate thickness of 1.6 mm or 1.8 mm and a width of 50 mm was used.
  • the tensile strength is the tensile strength obtained by preparing a JIS No. 5 tensile specimen from each steel plate in a direction parallel to the rolling direction and conducting a tensile test in accordance with the provisions of JIS Z 2241: 2011. is there.
  • the steel plate 4 having a flange portion was produced by bending the steel plate into an L-shaped cross-sectional shape.
  • An L-shaped steel plate 5 having the same steel type and the same plate thickness is fixed to a restraining jig in a state of being overlapped with a gap A as shown in FIG. 6 which is a perspective view showing test pieces of Examples and Comparative Examples.
  • the overlapped part of the flange is laser welded in the longitudinal direction, and after the laser welding, the restraining jig is removed, and an L-shaped test piece (laser welded joint) having a test piece width of 50 mm, a lateral wall length of 120 mm, and a flange width of 30 mm.
  • an L-shaped test piece (laser welded joint) having a test piece width of 50 mm, a lateral wall length of 120 mm, and a flange width of 30 mm.
  • the laser welding conditions, the gap A of the flange superposition portion of the steel plate 4 and the steel plate 5 before laser welding the size a, the weld S and final welding S f of welding speed v, the initial welding S i and the laser power P of the welding S, initial welding S i welding speed v i of the laser output P f of the final weld S f, was performed variously changed as shown in Table 1.
  • the vicinity of 1/5 of the total length of the bead was set to 1/5 of the total length of the bead
  • the vicinity of 4/5 of the total length of the bead was set to 4/5 of the total length of the bead.
  • the process of forming the bead from the bead starting end X to 1/5 of the total length of the bead is the initial welding S i
  • the process of forming the bead to 4/5 of the total length of the bead following the initial welding S i is the main welding S and the main welding.
  • a step subsequent to S to form a bead to bead end Y was final weld S f.
  • size a of the clearance gap A of the overlapping part of the flange before laser welding was uniform over the laser welding direction.
  • Fiber laser was used for laser welding, and the beam diameter at the focal position was fixed at 0.6 mm ⁇ . Welding was performed in the atmosphere, and the focal position during laser welding was the steel plate surface of the flange portion of the steel plate 4.
  • Table 1 shows the results of observation of the appearance of the beads of the obtained L-shaped laser welded joint. Specifically, the presence or absence of cracks in the beads was visually observed. Further, the bead width W of the bead body B, the bead width W i in the bead beginning 1/10 parts B i, and measures the bead width W f in bead termination 1/10 parts B f, the bead width ratio W i / W and W f / W were determined. In the present invention example and the comparative example, the bead main body B is located at 1/5 of the bead start end, which is 1/5 of the total beat length from the bead start end X, and at 1/5 of the bead total length from the bead end Y.
  • the size of the gap of the laser welded joint is measured by measuring the size of the gap at a position 5 mm away from the bead starting end X in the bead full length direction and a position 5 mm away from the bead end Y in the bead full length direction. It was.
  • the size of the gap between the obtained L-shaped laser welded joints in the thickness direction of the steel sheet was measured.
  • the peel strength of the obtained L-shaped laser welded joint was measured by an L-shaped tensile test in which a tensile load was applied from both sides. The tensile test was performed at a speed of 10 mm / min. The results are shown in Table 1.
  • the example of the present invention performed under the welding conditions satisfying the formula (1) has no cracks throughout the bead such as the bead end portion, and the bead width ratio W f / W is 0.80 or more. It was 1.20 or less, and the appearance was excellent.
  • fill Formula (1) has a peeling strength of 4.0 kN or more, and was joined by high intensity
  • the bead width ratio W i / W is also 0.80 or more and 1.20 or less, and the bead width ratio is uniform over the entire length of the bead. Had.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Laser Beam Processing (AREA)
  • Body Structure For Vehicles (AREA)
  • Manufacture Of Motors, Generators (AREA)

Abstract

Provided is a method of manufacturing a laser welded joint with which the occurrence of cracking in a bead terminal end portion is suppressed, and which has an excellent appearance. In this method of manufacturing a laser welded joint, for obtaining a laser welded joint by laser welding two steel sheets that are stacked vertically on one another with a gap therebetween, formula (1) is satisfied when t1 is the thickness of the upper steel sheet, t2 is the thickness of the lower steel sheet, a is the width of a gap between the upper steel sheet and the lower steel sheet, initial welding is a step of forming a bead from a bead start end to approximately 1/5 of the total length of the bead, main welding is a step of forming the bead, as a continuation of initial welding, to approximately 4/5 of the total length of the bead, final welding is a step of forming the bead, as a continuation of main welding, to a bead terminal end, P is the laser output during initial welding and main welding, and Pf is the laser output during final welding. 0.8((t1+t2)/(K+t1+t2))P<Pf<((t1+t2)/(K+t1+t2))P (1) (a is at most equal to the smaller of 0.5t1 and 0.5t2, and K=(t2/t1)a)

Description

レーザ溶接継手の製造方法、レーザ溶接継手および自動車用骨格部品Laser welded joint manufacturing method, laser welded joint, and automotive framework parts
　本発明は、レーザ溶接継手の製造方法、レーザ溶接継手および自動車用骨格部品に関する。 The present invention relates to a method for manufacturing a laser welded joint, a laser welded joint, and an automobile frame part.
　従来、自動車の構造部材の溶接には抵抗スポット溶接が用いられている。しかし、抵抗スポット溶接には、溶接に時間がかかるという問題や分流のためピッチを狭く出来ないという問題、さらには溶接機のガンによる空間的な制約があるという問題がある。そのため、近年、従来のスポット溶接に加えて、重ね合わせた鋼板の表面にレーザビームを照射して鋼板を接合するレーザ溶接の検討が行われてきている。レーザ溶接では、重ね合わせた鋼板の表面にレーザビームを照射して鋼板のレーザビーム照射部位を溶融および凝固させることによってビードが形成されると共に鋼板が接合されてレーザ溶接継手が得られる。しかし、ビードの終端側で割れが発生するという問題があり、割れが発生すると外観が悪くなる。外観が優れていることが求められている自動車の構造部材としては、該割れにより外観が悪くなったレーザ溶接継手は使い難い。また、割れが発生すると、レーザ溶接継手の剥離強度が低くなるという問題もある。 Conventionally, resistance spot welding is used for welding structural members of automobiles. However, resistance spot welding has a problem that it takes a long time to weld, a problem that the pitch cannot be narrowed due to a diversion, and a problem that there is a spatial restriction due to the gun of the welding machine. For this reason, in recent years, in addition to conventional spot welding, studies have been made on laser welding in which the steel plates are joined by irradiating the surface of the superposed steel plates with a laser beam. In laser welding, a laser beam is irradiated on the surface of the stacked steel plates to melt and solidify the laser beam irradiated portion of the steel plates, thereby forming beads and joining the steel plates to obtain a laser welded joint. However, there is a problem that cracks occur on the end side of the bead, and when the cracks occur, the appearance deteriorates. As a structural member of an automobile that is required to have an excellent appearance, it is difficult to use a laser welded joint whose appearance has deteriorated due to the crack. Moreover, when a crack generate | occur | produces, there also exists a problem that the peeling strength of a laser welded joint will become low.
　このビード終端側で割れが発生するという問題は、重ね合わせた鋼板の間に隙間がある場合に特に顕著になる。このような重ね合わせた鋼板の間に隙間がある状態でレーザ溶接する方法として、種々の技術が開示されている（例えば、特許文献１および特許文献２参照）。 The problem that cracking occurs at the end of the bead is particularly noticeable when there is a gap between the stacked steel sheets. Various techniques have been disclosed as a method of laser welding in a state where there is a gap between such stacked steel sheets (see, for example, Patent Document 1 and Patent Document 2).
　特許文献１の方法は、板と板の隙間の小さいほうから大きいほうに向けて溶接を行う方法であり、特殊なクランプ治具が必要な上、あらかじめ決められた溶接経路しか溶接することができないという問題がある。また、外観に関しては検討されていない。 The method of Patent Document 1 is a method of welding from the smaller gap between the plates to the larger one. A special clamping jig is required and only a predetermined welding path can be welded. There is a problem. In addition, the appearance has not been studied.
　また、特許文献２の方法は、溶接線をラップさせて溶接始終端部を再溶融させることで、溶接外観を向上させる方法であるが、溶接に時間がかかるという問題があり用い難い。 Further, the method of Patent Document 2 is a method of improving the appearance of welding by wrapping the welding line and remelting the welding start / end portion, but there is a problem that welding takes time and is difficult to use.
　なお、このようなビード終端部に割れが生じて外観が悪くなるという問題は、自動車の構造部材に限らず、その他の用途に用いられるレーザ溶接継手においても同様に存在する。 In addition, the problem that the bead end portion is cracked and the appearance is deteriorated is not limited to the structural member of the automobile, but also exists in laser welded joints used for other purposes.
特許第５１２５００１号Patent No. 5122501 特開２０１３－２１５７５５号公報JP 2013-215755 A
　本発明はかかる事情に鑑みてなされたものであって、ビード終端部での割れの発生が抑制され外観が優れたレーザ溶接継手の製造方法、レーザ溶接継手および自動車用骨格部品を提供することを目的とする。 The present invention has been made in view of such circumstances, and provides a laser welded joint manufacturing method, a laser welded joint, and an automobile skeleton component that are excellent in appearance by suppressing the occurrence of cracks at a bead end portion. Objective.
　上述したように、特に重ねた鋼板の間に隙間がある鋼板のレーザ溶接では、溶接終端部（ビード終端部）に、割れや欠陥が発生しやすい。本発明者らは上記課題を解決するために検討した。その結果、以下の知見を得た。 As described above, cracks and defects are likely to occur at the welding end portion (bead end portion) in laser welding of steel plates having a gap between the stacked steel plates. The present inventors have studied to solve the above problems. As a result, the following knowledge was obtained.
　溶接終了時は、ビード終端部での割れの発生防止のために、入熱を減らさなければならない。入熱を減らす方法としては、溶接終了時のレーザ出力を減らす方法と溶接速度を上げる方法が考えられる。しかしながら、溶接速度を上げる方法は、スパッタ発生量の増加が考えられる。そこで、溶接終了時のレーザ出力を減らす方法に着目し、ビード終端部での割れの発生防止を検討した。さらには、重ね合わせた鋼板の間に隙間がある場合は、定常時は隙間分（板隙分）のレーザ出力を増加させているので、溶接終了時には隙間分（板隙分）のレーザ出力を減少させる必要がある。 At the end of welding, heat input must be reduced to prevent cracking at the end of the bead. As a method for reducing the heat input, a method for reducing the laser output at the end of welding and a method for increasing the welding speed are conceivable. However, an increase in the amount of spatter can be considered as a method for increasing the welding speed. Therefore, paying attention to the method of reducing the laser output at the end of welding, we studied the prevention of cracks at the end of the bead. Furthermore, if there is a gap between the stacked steel plates, the laser output for the gap (plate gap) is increased during steady state, so the laser output for the gap (plate gap) is increased at the end of welding. It needs to be reduced.
　以上を考慮した結果、本発明者らは、２枚の鋼板の板厚、２枚の鋼板の間の隙間の大きさ、レーザ出力、これらの関係を制御する、すなわち、下記式（１）を満たすようにすることにより、ビード終端側での割れの発生が抑制できることを知見し、本発明を完成させた。
０．８((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ＜Ｐｆ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ　(1)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａ　（単位：ｍｍ）である。また、上側の鋼板の板厚をｔ１（ｍｍ）、下側の鋼板の板厚をｔ２（ｍｍ）、上側の鋼板と下側の鋼板との隙間の大きさをａ（ｍｍ）、初期溶接および本溶接でのレーザ出力をＰ（ｋＷ）、終期溶接でのレーザ出力をＰｆ（ｋＷ）とする。 As a result of taking the above into consideration, the present inventors control the thickness of the two steel plates, the size of the gap between the two steel plates, the laser output, and the relationship thereof, that is, the following equation (1): It was found that the occurrence of cracks on the bead end side can be suppressed by satisfying the requirements, and the present invention has been completed.
0.8 ((t 1 + t 2 ) / (K + t 1 + t 2 )) P <P f <((t 1 + t 2 ) / (K + t 1 + t 2 )) P (1)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) a ( unit: mm) is. Further, the thickness of the upper steel plate is t 1 (mm), the thickness of the lower steel plate is t 2 (mm), the size of the gap between the upper steel plate and the lower steel plate is a (mm), initial The laser output in welding and main welding is P (kW), and the laser output in final welding is P f (kW).
　上記式（１）を満たすことで、溶接終了時は溶融部分を小さくしておき、凝固時に溶接欠陥が発生しないように溶融部を安定させる。その結果、ビード終端部での割れの発生を防止する。 By satisfying the above formula (1), the melted portion is made small at the end of welding, and the melted portion is stabilized so that no welding defect occurs during solidification. As a result, the occurrence of cracks at the end of the bead is prevented.
　さらには、溶接始端部（ビード始端部）において、ビート幅が細くなってしまう場合がある。溶接開始時は、鋼板表面を溶融させるため、入熱増としなければならない。すなわち、鋼板表面を溶かすためにエネルギーが必要なため、溶接が安定しない。その結果、ビード始端部のビート幅が細くなってしまうことがわかった。入熱を増やす方法としては、溶接開始時のレーザ出力を増やす方法と溶接速度を下げる方法が考えられる。しかしながら、レーザ出力を増やす方法は、スパッタ発生量の増加が考えられる。そこで、溶接開始時の溶接速度を下げる方法に着目し、ビード始端部のビート幅が細くなるのを防止することを検討した。さらには、重ね合わせた鋼板の間に隙間がある場合のエネルギーロスも考慮する必要がある。 Furthermore, the beat width may become narrow at the welding start end (bead start end). At the start of welding, heat input must be increased to melt the steel plate surface. That is, since energy is required to melt the steel sheet surface, welding is not stable. As a result, it was found that the beat width at the beginning of the bead became narrow. As a method of increasing the heat input, a method of increasing the laser output at the start of welding and a method of decreasing the welding speed are conceivable. However, an increase in the amount of spatter can be considered as a method for increasing the laser output. Therefore, paying attention to the method of lowering the welding speed at the start of welding, we studied to prevent the bead width at the bead start end from becoming narrow. Furthermore, it is necessary to consider energy loss when there is a gap between the stacked steel sheets.
　以上を考慮した結果、本発明者らは、２枚の鋼板の板厚、２枚の鋼板の間の隙間の大きさ、溶接速度、これらの関係を制御する、すなわち、下記式（２）を満たすようにすることにより、ビード始端部のビート幅が細くなることを抑制できることを知見した。
０．７５((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ＜ｖｉ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ　　(2)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａである。また、上側の鋼板の板厚をｔ１（ｍｍ）、下側の鋼板の板厚をｔ２（ｍｍ）、上側の鋼板と下側の鋼板との隙間の大きさをａ（ｍｍ）、本溶接および終期溶接での溶接速度をｖ（ｍ／ｍｉｎ）、初期溶接での溶接速度をｖｉ（ｍ／ｍｉｎ）とする。 As a result of taking the above into consideration, the present inventors control the thickness of the two steel plates, the size of the gap between the two steel plates, the welding speed, and the relationship thereof, that is, the following equation (2): It has been found that by satisfying the condition, it is possible to suppress the beat width at the bead starting end from becoming narrow.
0.75 ((t 1 + t 2 ) / (K + t 1 + t 2)) v <v i <((t 1 + t 2) / (K + t 1 + t 2)) v (2)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) is a. Further, the thickness of the upper steel plate is t 1 (mm), the thickness of the lower steel plate is t 2 (mm), the size of the gap between the upper steel plate and the lower steel plate is a (mm), this The welding speed in welding and final welding is v (m / min), and the welding speed in initial welding is vi (m / min).
　上記式（２）を満たすことで、溶融池が溶接直後でも安定する。その結果、ビード始端部のビート幅が細くなることを抑制できる。 When the above formula (2) is satisfied, the molten pool is stabilized even immediately after welding. As a result, it is possible to suppress the beat width at the bead starting end from becoming narrow.
　本発明は上記の知見に基づき完成されたものであり、その要旨は次のとおりである。 The present invention has been completed based on the above findings, and the gist thereof is as follows.
　［１］　２枚の鋼板をその間に隙間を有するように上下に重ね合わせた状態でレーザビームを上側の鋼板表面に照射してレーザビームが照射された部位を溶融および凝固させてビードを形成すると共に２枚の鋼板を接合するレーザ溶接により２枚の鋼板が接合されたレーザ溶接継手を得るレーザ溶接継手の製造方法であって、
　上側の鋼板の板厚をｔ１（ｍｍ）、下側の鋼板の板厚をｔ２（ｍｍ）、上側の鋼板と下側の鋼板との隙間の大きさをａ（ｍｍ）とし、
ビード始端からビード全長の１／５近傍までビードを形成する工程を初期溶接、該初期溶接に続いてビード全長の４／５近傍までビードを形成する工程を本溶接、該本溶接に続いてビード終端までビードを形成する工程を終期溶接とし、
前記初期溶接および前記本溶接でのレーザ出力をＰ（ｋＷ）、前記終期溶接でのレーザ出力をＰｆ（ｋＷ）としたときに、
下記式（１）を満たすことを特徴とするレーザ溶接継手の製造方法。
０．８((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ＜Ｐｆ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ　(1)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａ　（単位：ｍｍ）である。 [1] A laser beam is irradiated on the upper steel plate surface with two steel plates stacked vertically so as to have a gap between them, and a portion irradiated with the laser beam is melted and solidified to form a bead. And a method of manufacturing a laser welded joint for obtaining a laser welded joint in which two steel plates are joined by laser welding for joining two steel plates together,
The plate thickness of the upper steel plate is t 1 (mm), the plate thickness of the lower steel plate is t 2 (mm), the size of the gap between the upper steel plate and the lower steel plate is a (mm),
Initial welding is the process of forming a bead from the beginning of the bead to the vicinity of 1/5 of the total length of the bead. The initial welding is followed by the process of forming the bead to the vicinity of 4/5 of the total length of the bead. The process of forming the bead to the end is the final welding,
When the laser output in the initial welding and the main welding is P (kW), and the laser output in the final welding is P f (kW),
The manufacturing method of the laser welded joint characterized by satisfy | filling following formula (1).
0.8 ((t 1 + t 2 ) / (K + t 1 + t 2 )) P <P f <((t 1 + t 2 ) / (K + t 1 + t 2 )) P (1)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) a ( unit: mm) is.
　［２］　前記本溶接および前記終期溶接での溶接速度をｖ（ｍ／ｍｉｎ）、前記初期溶接での溶接速度をｖｉ（ｍ／ｍｉｎ）としたときに、
下記式（２）を満たすことを特徴とする［１］に記載するレーザ溶接継手の製造方法。
０．７５((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ＜ｖｉ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ　(2)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａである。 [2] When the welding speed in the main welding and the final welding is v (m / min), and the welding speed in the initial welding is vi (m / min),
The method for producing a laser welded joint according to [1], wherein the following formula (2) is satisfied.
0.75 ((t 1 + t 2 ) / (K + t 1 + t 2)) v <v i <((t 1 + t 2) / (K + t 1 + t 2)) v (2)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) is a.
　［３］　２枚の鋼板からなるレーザ溶接継手であって、
前記２枚の鋼板の間に隙間を有し、
前記隙間の大きさが、２枚の鋼板のうち薄い方の板厚の１０％～５０％であり、
前記２枚の鋼板のうち上側の鋼板表面に形成されたビードが、
ビード始端からビート全長の１／５の位置であるビード始端１／５部近傍と、ビード終端からビード全長の１／５の位置であるビード終端１／５部近傍と、の間をビード本体とし、
ビード終端からビード全長の１／１０の位置をビード終端１／１０部とし、
ビード本体のビード幅をＷ、ビード終端１／１０部でのビード幅をＷｆとしたときに、
下記式（３）を満たすことを特徴とするレーザ溶接継手。
0.80≦Ｗｆ／Ｗ≦1.20　　(3)
　［４］　ビード始端からビート全長の１／１０の位置をビード始端１／１０部とし、
ビード始端１／１０部でのビード幅をＷｉとしたときに、
下記式（４）を満たすことを特徴とする［３］に記載するレーザ溶接継手。
0.80≦Ｗｉ／Ｗ≦1.20　　(4)
　［５］　［３］または［４］に記載するレーザ溶接継手であって、前記２枚の鋼板はそれぞれ引張強度が９８０ＭＰａ以上の高強度鋼板であるレーザ溶接継手を有することを特徴とする自動車用骨格部品。 [3] A laser welded joint made of two steel plates,
Having a gap between the two steel plates,
The size of the gap is 10% to 50% of the thinner one of the two steel plates,
A bead formed on the upper steel plate surface of the two steel plates,
The bead body is between the bead start end 1/5 portion, which is 1/5 of the total beat length from the bead start end, and the bead end 1/5 portion, which is 1/5 of the bead end length, from the bead end. ,
The position of 1/10 of the total length of the bead from the end of the bead is 1/10 part of the bead end,
When the bead width of the bead body is W and the bead width at the bead end 1/10 part is W f ,
A laser welded joint satisfying the following formula (3).
0.80 ≦ W f /W≦1.20 (3)
[4] The position of 1/10 of the total beat length from the bead start end is 1/10 part of the bead start end.
A bead width at the bead beginning 1/10 parts when the W i,
The laser weld joint according to [3], which satisfies the following formula (4).
0.80 ≦ W i /W≦1.20 (4)
[5] The laser welded joint according to [3] or [4], wherein the two steel plates each have a laser welded joint which is a high strength steel plate having a tensile strength of 980 MPa or more. Skeletal parts.
　［６］　前記２枚の鋼板は、それぞれ、質量％で、Ｃ：０．０７％超え０．２５％以下、Ｐ＋Ｓ：０．０３％未満、Ｍｎ：１．８％以上３．０％以下、Ｓｉ：１．２％超え１．８％以下を含有し、下記Ａ群および下記Ｂ群の少なくとも一方を含有し、残部がＦｅおよび不可避的不純物からなる成分組成を有し、板厚が１．０ｍｍ以上２．０ｍｍ以下であることを特徴とする［５］に記載する自動車用骨格部品。
Ａ群：　Ｔｉ：０．００５％以上０．０１％以下およびＮｂ：０．００５％以上０．０５０％未満の少なくとも一方
Ｂ群：　Ｃｒ：１．０％以下、Ｍｏ：０．５０％以下およびＢ：０．１０％以下から選択される少なくとも一種 [6] The two steel sheets are each in mass%, C: more than 0.07% and 0.25% or less, P + S: less than 0.03%, Mn: 1.8% or more and 3.0% or less, Si: More than 1.2% and not more than 1.8%, containing at least one of the following group A and group B, with the balance being composed of Fe and inevitable impurities, with a plate thickness of 1. It is 0 mm or more and 2.0 mm or less, The frame part for motor vehicles described in [5] characterized by the above-mentioned.
Group A: Ti: 0.005% or more and 0.01% or less and Nb: 0.005% or more and less than 0.050% Group B: Cr: 1.0% or less, Mo: 0.50% or less and B: At least one selected from 0.10% or less
　本発明によれば、隙間を有するように重ね合わせた２枚の鋼板のレーザ溶接におけるビード終端側での割れの発生が抑制されるため、外観に優れたレーザ溶接継手を製造することができる。また、割れの発生が抑制されるため、剥離強度が高く安全性に優れたレーザ溶接継手を製造することができる。また、特許文献２のようにビード始終端部を再溶融させる必要がないため、短時間でレーザ溶接継手を製造することができる。 According to the present invention, since the occurrence of cracks at the bead end side in laser welding of two steel plates that are overlapped so as to have a gap is suppressed, a laser welded joint having an excellent appearance can be manufactured. Moreover, since generation | occurrence | production of a crack is suppressed, the laser welding joint with high peeling strength and excellent safety | security can be manufactured. Moreover, since it is not necessary to remelt the bead start / end portion as in Patent Document 2, a laser welded joint can be manufactured in a short time.
　さらに、ビード幅をビード全体に亘って均一にすることができ、より外観が優れたレーザ溶接継手を製造することができる。 Furthermore, the bead width can be made uniform over the entire bead, and a laser welded joint with a better appearance can be manufactured.
　また、本発明のレーザ溶接継手は外観に優れているため、自動車の構造部材に好適に用いることができ、例えば接合する鋼板として高強度鋼板を用いることにより自動車用骨格部品とすることができる。 Further, since the laser welded joint of the present invention is excellent in appearance, it can be suitably used for a structural member of an automobile. For example, a high-strength steel sheet can be used as a steel sheet to be joined to form a skeletal part for an automobile.
本発明のレーザ溶接継手の外観を示す斜視図および要部拡大図である。It is the perspective view and principal part enlarged view which show the external appearance of the laser welded joint of this invention. 本発明のレーザ溶接継手の断面拡大図である。It is a cross-sectional enlarged view of the laser welded joint of the present invention. 本発明のレーザ溶接継手の上側の鋼板の表面に形成されたビードを示す上面図である。It is a top view which shows the bead formed in the surface of the steel plate of the upper side of the laser welded joint of this invention. Ｃ字状のビードが形成された本発明のレーザ溶接継手の外観を示す斜視図である。It is a perspective view which shows the external appearance of the laser welded joint of this invention in which the C-shaped bead was formed. Ｓ字状のビードが形成された本発明のレーザ溶接継手の外観を示す斜視図である。It is a perspective view which shows the external appearance of the laser welded joint of this invention in which the S-shaped bead was formed. 実施例および比較例の試験片を示す斜視図である。It is a perspective view which shows the test piece of an Example and a comparative example.
　本発明のレーザ溶接継手の製造方法は、２枚の鋼板をその間に隙間を有するように上下に重ね合わせた状態でレーザビームを上側の鋼板表面に照射してレーザビームが照射された部位を溶融および凝固させてビードを形成すると共に２枚の鋼板を接合するレーザ溶接により２枚の鋼板が接合されたレーザ溶接継手を得るものである。そして、上側の鋼板の板厚をｔ１（ｍｍ）、下側の鋼板の板厚をｔ２（ｍｍ）、上側の鋼板と下側の鋼板との隙間の大きさをａ（ｍｍ）とし、ビード始端からビード全長の１／５近傍までビードを形成する工程を初期溶接、該初期溶接に続いてビード全長の４／５近傍までビードを形成する工程を本溶接、該本溶接に続いてビード終端までビードを形成する工程を終期溶接とし、初期溶接および本溶接でのレーザ出力をＰ（ｋＷ）、終期溶接でのレーザ出力をＰｆ（ｋＷ）としたときに、下記式（１）を満たすことを特徴とする。
０．８((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ＜Ｐｆ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ　(1)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａ　（単位：ｍｍ）である。 The method of manufacturing a laser welded joint according to the present invention melts a portion irradiated with a laser beam by irradiating the surface of the upper steel plate with two steel plates stacked vertically with a gap between them. In addition, a laser weld joint in which two steel plates are joined is obtained by laser welding that solidifies and forms a bead and joins two steel plates. And the plate thickness of the upper steel plate is t 1 (mm), the plate thickness of the lower steel plate is t 2 (mm), and the size of the gap between the upper steel plate and the lower steel plate is a (mm), Initial welding is the process of forming a bead from the beginning of the bead to the vicinity of 1/5 of the total length of the bead. The initial welding is followed by the process of forming the bead to the vicinity of 4/5 of the total length of the bead. When the process of forming the bead to the end is the final welding, the laser output in the initial welding and the main welding is P (kW), and the laser output in the final welding is P f (kW), the following equation (1) It is characterized by satisfying.
0.8 ((t 1 + t 2 ) / (K + t 1 + t 2 )) P <P f <((t 1 + t 2 ) / (K + t 1 + t 2 )) P (1)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) a ( unit: mm) is.
　このような本発明のレーザ溶接継手１の製造方法について、本発明の一例である図１～図３を用いて以下に詳細に説明する。図１（ａ）は、本発明のレーザ溶接継手の製造方法で製造される本発明のレーザ溶接継手の外観を示す斜視図であり、図１（ｂ）は、図１（ａ）の要部拡大図である。図２は、本発明のレーザ溶接継手の製造方法で製造されるレーザ溶接継手の断面拡大図である。図３は、本発明のレーザ溶接継手の製造方法で製造されるレーザ溶接継手の上側の鋼板の表面に形成されたビードを示す上面図である。 Such a method for manufacturing the laser welded joint 1 of the present invention will be described in detail below with reference to FIGS. 1 to 3 which are examples of the present invention. Fig.1 (a) is a perspective view which shows the external appearance of the laser welded joint of this invention manufactured with the manufacturing method of the laser welded joint of this invention, FIG.1 (b) is the principal part of FIG.1 (a). It is an enlarged view. FIG. 2 is an enlarged cross-sectional view of a laser welded joint manufactured by the laser welded joint manufacturing method of the present invention. FIG. 3 is a top view showing a bead formed on the surface of the upper steel plate of the laser welded joint manufactured by the laser welded joint manufacturing method of the present invention.
　本発明のレーザ溶接継手の製造方法では、まず、２枚の鋼板として、例えば図１（ａ）に示すように、ハット形状の鋼板（ハット部上板）４および鋼板（ハット部下板）５を、その間に隙間を有するように上下に重ね合わせる。 In the laser welded joint manufacturing method of the present invention, first, as shown in FIG. 1A, for example, as shown in FIG. 1A, a hat-shaped steel plate (hat portion upper plate) 4 and a steel plate (hat portion lower plate) 5 are used. , And overlap each other so that there is a gap between them.
　本発明においてレーザ溶接する対象は、鋼板（鋼板４、鋼板５）である。鋼板４および鋼板５の種類は特に限定されないが、例えば引張強度が９８０ＭＰａ以上の高強度鋼板であることが好ましい。９８０ＭＰａ以上の高強度鋼板は、炭素等量が比較的高いためビード終端側に割れが発生しやすい。しかしながら、本発明のレーザ溶接継手の製造方法ではビード終端側の割れの発生が抑制でき、高強度鋼板を用いても割れの発生が抑制され優れた外観を有するレーザ溶接継手を製造することができる。このように例えば引張強度９８０ＭＰａ以上の高強度鋼板のレーザ溶接継手とすることにより、強度が求められる自動車用骨格部材として好適に使用することができる。 In the present invention, the object to be laser welded is a steel plate (steel plate 4, steel plate 5). Although the kind of the steel plate 4 and the steel plate 5 is not specifically limited, For example, it is preferable that it is a high strength steel plate with a tensile strength of 980 MPa or more. A high-strength steel sheet of 980 MPa or more is likely to crack on the bead end side because the carbon equivalent is relatively high. However, in the method for producing a laser welded joint according to the present invention, the occurrence of cracks on the bead end side can be suppressed, and even when a high-strength steel plate is used, the occurrence of cracks is suppressed and a laser welded joint having an excellent appearance can be produced. . Thus, for example, by using a laser-welded joint of a high-strength steel plate having a tensile strength of 980 MPa or more, it can be suitably used as an automobile skeleton member that requires strength.
　鋼板４および鋼板５の成分組成は特に限定されないが、例えば、質量％で、Ｃ：０．０７％超え０．２５％以下、Ｐ＋Ｓ：０．０３％未満、Ｍｎ：１．８％以上３．０％以下、Ｓｉ：１．２％超え１．８％以下を含有し、下記Ａ群および下記Ｂ群の少なくとも一方を含有し、残部Ｆｅおよび不可避的不純物からなる成分組成を有するものとすることができる。以下、各成分組成における％とは、質量％のことを指す。
Ａ群：　Ｔｉ：０．００５％以上０．０１％以下およびＮｂ：０．００５％以上０．０５０％未満の少なくとも一方
Ｂ群：　Ｃｒ：１．０％以下、Ｍｏ：０．５０％以下およびＢ：０．１０％以下から選択される少なくとも一種
　（Ｃ：０．０７％超え０．２５％以下）
　Ｃ含有量が０．０７％超えであると、析出強化の効果を得ることができなくなる場合がない。一方、Ｃ含有量が０．２５％以下であると、粗大な炭化物の析出を招くことがなく、所望の高強度、加工性を確保できる。そのため、Ｃ含有量は０．０７％超え０．２５％以下とすることが好ましい。 Although the component composition of the steel plate 4 and the steel plate 5 is not specifically limited, For example, by mass%, C: more than 0.07% and 0.25% or less, P + S: less than 0.03%, Mn: 1.8% or more 3. It shall contain 0% or less, Si: more than 1.2% and 1.8% or less, at least one of the following group A and group B, and a component composition consisting of the remainder Fe and inevitable impurities Can do. Hereinafter,% in each component composition refers to mass%.
Group A: Ti: 0.005% or more and 0.01% or less and Nb: 0.005% or more and less than 0.050% Group B: Cr: 1.0% or less, Mo: 0.50% or less and B: At least one selected from 0.10% or less (C: more than 0.07% and 0.25% or less)
If the C content exceeds 0.07%, the effect of precipitation strengthening cannot be obtained. On the other hand, when the C content is 0.25% or less, it is possible to ensure desired high strength and workability without causing precipitation of coarse carbides. Therefore, the C content is preferably 0.07% to 0.25% or less.
　（Ｐ＋Ｓ：０．０３％未満）
　Ｐ含有量とＳ含有量の合計量（Ｐ＋Ｓ）が０．０３％未満であると、延性および靱性が低下せず、所望の高強度、加工性を確保できる。そのため、Ｐ含有量とＳ含有量の合計量（Ｐ＋Ｓ）は０．０３％未満とすることが好ましい。 (P + S: less than 0.03%)
When the total amount of P content and S content (P + S) is less than 0.03%, ductility and toughness are not lowered, and desired high strength and workability can be secured. Therefore, the total amount (P + S) of the P content and the S content is preferably less than 0.03%.
　（Ｍｎ：１．８％以上３．０％以下）
　Ｍｎ含有量が１．８％以上であると、十分な焼入れ性が確保でき、粗大な炭化物が析出しない。一方、Ｍｎ含有量が３．０％以下であると、粒界脆化感受性が増加して靱性、耐低温割れ性が劣化しない。そのため、Ｍｎ含有量は１．８％以上３．０％以下とすることが好ましい。Ｍｎ含有量は２．５％以下であることがより好ましい。 (Mn: 1.8% to 3.0%)
When the Mn content is 1.8% or more, sufficient hardenability can be secured, and coarse carbides do not precipitate. On the other hand, when the Mn content is 3.0% or less, the grain boundary embrittlement susceptibility increases and the toughness and the cold cracking resistance do not deteriorate. Therefore, the Mn content is preferably 1.8% or more and 3.0% or less. The Mn content is more preferably 2.5% or less.
　（Ｓｉ：１．２％超え１．８％以下）
　Ｓｉ含有量が１．２％超えであると、固溶して鋼の強度を増加させる効果が十分に得られる。一方、Ｓｉ含有量が１．８％以下であると、溶接熱影響部の硬化が大きくならず、溶接熱影響部の靱性、耐低温割れ性が劣化しない。そのため、Ｓｉ含有量は１．２％超え１．８％以下とすることが好ましい。Ｓｉ含有量は１．５％以下であることがより好ましい。 (Si: 1.2% to 1.8% or less)
When the Si content exceeds 1.2%, the effect of increasing the strength of the steel by solid solution is sufficiently obtained. On the other hand, when the Si content is 1.8% or less, the hardening of the weld heat affected zone does not increase, and the toughness and the low temperature crack resistance of the weld heat affected zone do not deteriorate. For this reason, the Si content is preferably 1.2% to 1.8%. The Si content is more preferably 1.5% or less.
　（Ａ群：　Ｔｉ：０．００５％以上０．０１０％以下およびＮｂ：０．００５％以上０．０５０％未満の少なくとも一方）
　ＴｉやＮｂは炭化物または窒化物として析出し、焼鈍中のオーステナイトの粗大化を抑制する作用を有する。したがって、これらの元素の少なくとも１種を含有させることが好ましい。この効果を得るには、Ｔｉは０．００５％以上、Ｎｂは０．００５％以上含有させる。しかし、過剰に含有させても上記作用による効果が飽和して不経済となる。そればかりか、焼鈍時の再結晶温度が上昇し、焼鈍後の金属組織が不均一となり、伸びフランジ性も損なわれる。さらには、炭化物または窒化物の析出量が増し、降伏比が上昇し、形状凍結性も劣化する。したがって、Ｔｉ含有量は０．０１０％以下、Ｎｂ含有量は、０．０５０％未満とする。Ｔｉ含有量は好ましくは０．００８％未満であり、Ｎｂ含有量は好ましくは０．０４０％未満とする。 (Group A: Ti: 0.005% or more and 0.010% or less and Nb: 0.005% or more and less than 0.050%)
Ti and Nb are precipitated as carbides or nitrides, and have an action of suppressing austenite coarsening during annealing. Therefore, it is preferable to contain at least one of these elements. In order to obtain this effect, 0.005% or more of Ti and 0.005% or more of Nb are contained. However, even if it contains excessively, the effect by the said effect | action will be saturated and it will become uneconomical. In addition, the recrystallization temperature during annealing increases, the metal structure after annealing becomes non-uniform, and stretch flangeability is also impaired. Furthermore, the precipitation amount of carbide or nitride increases, the yield ratio increases, and the shape freezing property also deteriorates. Therefore, the Ti content is 0.010% or less, and the Nb content is less than 0.050%. The Ti content is preferably less than 0.008% and the Nb content is preferably less than 0.040%.
　（Ｂ群：　Ｃｒ：１．０％以下、Ｍｏ：０．５０％以下およびＢ：０．１０％以下から選択される少なくとも一種）
　Ｃｒ、ＭｏおよびＢは、鋼の焼入性を向上させる作用を有する元素である。したがってこれらの元素の１種類以上を含有させてもよい。しかしながら、これらの元素を過剰に含有させても上記の効果が飽和して不経済となる。したがって、これらの元素を含有させる場合には、Ｃｒ含有量は１．０％以下、Ｍｏ含有量は０．５０％以下、Ｂ含有量は０．１０％以下とする。Ｃｒ含有量は好ましくは０．５０％以下であり、Ｍｏ含有量は好ましくは０．１０％以下であり、Ｂ含有量は好ましくは０．０３０％以下である。Ｃｒ含有量は好ましくは０．０１％以上であり、Ｍｏ含有量は好ましくは０．００４％以上であり、Ｂ含有量は好ましくは０．０００１％以上である。 (Group B: Cr: 1.0% or less, Mo: 0.50% or less and B: at least one selected from 0.10% or less)
Cr, Mo, and B are elements having an effect of improving the hardenability of steel. Therefore, you may contain 1 or more types of these elements. However, even if these elements are contained excessively, the above effects are saturated and uneconomical. Therefore, when these elements are contained, the Cr content is 1.0% or less, the Mo content is 0.50% or less, and the B content is 0.10% or less. The Cr content is preferably 0.50% or less, the Mo content is preferably 0.10% or less, and the B content is preferably 0.030% or less. The Cr content is preferably 0.01% or more, the Mo content is preferably 0.004% or more, and the B content is preferably 0.0001% or more.
　（残部Ｆｅおよび不可避的不純物）
　上記成分組成以外の残部は、Ｆｅおよび不可避的不純物である。不可避的不純物としては、Ａｌ：０．０１５～０．０５０％、Ｎ：０．００２～０．００５％等が挙げられる。 (Remainder Fe and inevitable impurities)
The balance other than the above component composition is Fe and inevitable impurities. Inevitable impurities include Al: 0.015 to 0.050%, N: 0.002 to 0.005%, and the like.
　本発明においてレーザ溶接する対象である２枚の鋼板の板厚は特に限定されないが、例えば１．０ｍｍ以上２．０ｍｍ以下の範囲内であることが好ましい。さらに好ましくは、１．２ｍｍ以上１．８ｍｍ以下である。板厚がこの範囲内である鋼板は、自動車用骨格部材として好適に使用することができる。具体的には上側の鋼板４の板厚ｔ１は１．０ｍｍ≦ｔ１≦２．０ｍｍを満たし、下側の鋼板４の板厚ｔ２は１．０ｍｍ≦ｔ２≦２．０ｍｍを満たすことが好ましい。上側の鋼板４の板厚ｔ１は１．２ｍｍ≦ｔ１≦１．８ｍｍを満たし、下側の鋼板４の板厚ｔ２は１．２ｍｍ≦ｔ２≦１．８ｍｍを満たすことがさらに好ましい。 In the present invention, the thickness of the two steel plates to be laser welded is not particularly limited, but is preferably in the range of, for example, 1.0 mm or more and 2.0 mm or less. More preferably, they are 1.2 mm or more and 1.8 mm or less. A steel plate having a thickness within this range can be suitably used as an automobile skeleton member. Specifically, the plate thickness t 1 of the upper steel plate 4 satisfies 1.0 mm ≦ t 1 ≦ 2.0 mm, and the plate thickness t 2 of the lower steel plate 4 satisfies 1.0 mm ≦ t 2 ≦ 2.0 mm. It is preferable. It is more preferable that the plate thickness t 1 of the upper steel plate 4 satisfies 1.2 mm ≦ t 1 ≦ 1.8 mm, and the plate thickness t 2 of the lower steel plate 4 satisfies 1.2 mm ≦ t 2 ≦ 1.8 mm. .
　なお、２枚の鋼板４および鋼板５は、同じでも異なっていてもよく、鋼板４および鋼板５が、同種および同形状の鋼板であってもよいし、異種や異形状の鋼板であってもよい。 The two steel plates 4 and 5 may be the same or different, and the steel plate 4 and the steel plate 5 may be the same type and the same shape, or different types and different shapes. Good.
　そして、本発明においては、図２に示すように、レーザ溶接前の鋼板４と鋼板５との間には隙間Ａが存在する。 And in this invention, as shown in FIG. 2, the clearance gap A exists between the steel plate 4 and the steel plate 5 before laser welding.
　レーザ溶接前の鋼板４と鋼板５との隙間Ａの大きさａ（ｍｍ）、すなわち、鋼板４と鋼板５との隙間Ａの鋼板の板厚方向の大きさは、０．５ｔ１と０．５ｔ２のうちの小さい方以下を満たす必要がある。換言すると、レーザ溶接前の鋼板４と鋼板５との隙間Ａの大きさａは、上側の鋼板４の板厚ｔ１が下側の鋼板５の板厚ｔ２よりも小さい場合はａ≦０．５ｔ１を満たし、下側の鋼板５の板厚ｔ２が上側の鋼板４の板厚ｔ１よりも小さい場合はａ≦０．５ｔ２を満たし、ｔ１＝ｔ２の場合はａ≦０．５ｔ１＝０．５ｔ２を満たす。隙間Ａの大きさａがこの範囲外であると、割れが発生する。隙間Ａの大きさａは、上記範囲内であれば特に限定されないが、例えば０．１ｍｍ以上０．９ｍｍ以下であることが好ましい。例えば自動車用骨格部品の素材として好適に用いられる板厚１．０ｍｍ以上２．０ｍｍ以下の鋼板を用いて本発明のレーザ溶接継手の製造方法によりレーザ溶接継手を製造すると、隙間Ａの大きさａが０．９ｍｍより大きいと、溶接時に融落ちが発生してしまう場合があるからである。なお、レーザ溶接前の鋼板４と鋼板５との隙間Ａの大きさａは、レーザ溶接方向（上側の鋼板４の表面に照射するレーザビームを上側の鋼板４表面で移動させる方向）に亘って均一であり、隙間Ａを空けて重ね合わせた鋼板４および鋼板５を拘束治具等で固定し隙間Ａを保持した状態でレーザ溶接する。 The size a (mm) of the gap A between the steel plate 4 and the steel plate 5 before laser welding, that is, the size in the plate thickness direction of the steel plate of the gap A between the steel plate 4 and the steel plate 5 is 0.5 t 1 . It must satisfy the following smaller of 5t 2. In other words, the size a of the gap A between the steel plate 4 and the steel plate 5 before laser welding is such that a ≦ 0 when the plate thickness t 1 of the upper steel plate 4 is smaller than the plate thickness t 2 of the lower steel plate 5. When 0.5 t 1 is satisfied and the thickness t 2 of the lower steel plate 5 is smaller than the thickness t 1 of the upper steel plate 4, a ≦ 0.5 t 2 is satisfied, and when t 1 = t 2 , a ≦ 0.5t 1 = 0.5t 2 is satisfied. If the size a of the gap A is out of this range, cracking occurs. Although the magnitude | size a of the clearance gap A will not be specifically limited if it is in the said range, For example, it is preferable that they are 0.1 mm or more and 0.9 mm or less. For example, when a laser welded joint is manufactured by the method for manufacturing a laser welded joint using a steel plate having a thickness of 1.0 mm or more and 2.0 mm or less that is preferably used as a material for a framework part for an automobile, the size a of the gap A If the thickness is larger than 0.9 mm, meltdown may occur during welding. In addition, the magnitude | size a of the clearance gap A between the steel plate 4 and the steel plate 5 before laser welding is over the laser welding direction (the direction in which the laser beam irradiated to the surface of the upper steel plate 4 is moved on the surface of the upper steel plate 4). Laser welding is performed in a state in which the steel plate 4 and the steel plate 5 which are uniform and overlapped with a gap A therebetween are fixed with a restraining jig or the like and the gap A is held.
　このように上下に重ね合わせた状態でレーザ溶接するときに、２枚の鋼板４、５の間に隙間Ａがあると、得られるレーザ溶接継手のビード７の終端側に割れが生じやすい。特に、隙間Ａの大きさａが大きい場合、ビード終端側の割れが発生しやすい。しかしながら、本発明においては、式（１）を満たすレーザ溶接でレーザ溶接継手を製造するため、後述する実施例に示すように、割れの発生が抑制されたレーザ溶接継手を得ることができる。なお、レーザ溶接することにより得られるレーザ溶接継手の鋼板４と鋼板５との隙間の大きさ（鋼板の板厚方向の大きさ）は、レーザ溶接前の鋼板４と鋼板５との隙間Ａの大きさａよりも狭くなり、本発明のレーザ溶接継手の製造方法によって得られる本発明のレーザ溶接継手の鋼板４と鋼板５との隙間は、例えば、２枚の鋼板のうち薄い方の板厚の１０％～５０％、具体的には、例えば０．１ｍｍ以上０．９ｍｍ以下である。 In this way, when laser welding is performed in a state where they are stacked one above the other, if there is a gap A between the two steel plates 4 and 5, cracks are likely to occur on the end side of the bead 7 of the obtained laser welded joint. In particular, when the size a of the gap A is large, cracks on the bead end side are likely to occur. However, in the present invention, since a laser welded joint is manufactured by laser welding satisfying the expression (1), a laser welded joint in which the occurrence of cracks is suppressed can be obtained as shown in Examples described later. The size of the gap between the steel plate 4 and the steel plate 5 of the laser welded joint obtained by laser welding (the size in the plate thickness direction of the steel plate) is the gap A between the steel plate 4 and the steel plate 5 before laser welding. The gap between the steel plate 4 and the steel plate 5 of the laser welded joint of the present invention obtained by the laser welded joint manufacturing method of the present invention is narrower than the size a, for example, the thinner one of the two steel plates 10% to 50%, specifically 0.1 mm or more and 0.9 mm or less, for example.
　このように、２枚の鋼板４および鋼板５をその間に隙間Ａを有するように重ね合わせた状態で、レーザ溶接で接合する。具体的には、重ね合わせた鋼板のうち上側の鋼板４の表面にレーザビーム３を照射すると共に、レーザビーム３を重ね合わせた状態のままの鋼板４および鋼板５に対して相対的に移動させる。これにより、鋼板４および鋼板５のうちレーザビーム３で照射された部位が溶融して溶融部が形成され、その後溶融部が凝固してビード（溶接線）７が形成される。 Thus, in a state where the two steel plates 4 and 5 are overlapped with a gap A therebetween, they are joined by laser welding. Specifically, the surface of the upper steel plate 4 among the superposed steel plates is irradiated with the laser beam 3, and the laser beam 3 is moved relative to the steel plates 4 and 5 in the superposed state. . As a result, the portion irradiated with the laser beam 3 of the steel plate 4 and the steel plate 5 is melted to form a melted portion, and then the melted portion is solidified to form a bead (weld line) 7.
　本発明においては、このレーザ溶接条件が上記式（１）を満たす。具体的には、図３に示すように、ビード始端Ｘからビード全長の１／５近傍までビードを形成する工程を初期溶接Ｓｉ、初期溶接Ｓｉに続いてビード全長の４／５近傍までビードを形成する工程を本溶接Ｓ、本溶接Ｓに続いてビード終端Ｙまでビードを形成する工程を終期溶接Ｓｆとし、初期溶接Ｓｉおよび本溶接Ｓでのレーザ出力をＰ（ｋＷ）としたときに、終期溶接Ｓｆでのレーザ出力Ｐｆ（ｋＷ）は上記式（１）満たす。ビード全長の１／５近傍とは、ビード全長の１／５±ビード全長の３／４０の範囲内、すなわち、ビード全長の５／４０からビード全長の１１／４０までの範囲内である。また、ビード全長の４／５近傍とは、ビード全長の４／５±ビード全長の３／４０の範囲内、すなわち、ビード全長２９／４０からビード全長の３５／４０までの範囲内である。図３においては、ビード全長の１／５近傍をビード全長の１／５とし、また、ビード全長の４／５近傍をビード全長の４／５とした例を示している。 In the present invention, this laser welding condition satisfies the above formula (1). Specifically, as shown in FIG. 3, the process of forming the bead from the bead starting end X to the vicinity of 1/5 of the total length of the bead is performed to the initial welding S i and the initial welding S i to the vicinity of 4/5 of the total length of the bead. this welding step of forming a bead S, forming a bead to bead end Y Following the welding S and final welding S f, the laser output at the initial weld S i and the welding S and P (kW) In this case, the laser output P f (kW) in the final welding S f satisfies the above formula (1). The vicinity of 1/5 of the total length of the bead is within a range of 1/5 of the total length of the bead ± 3/40 of the total length of the bead, that is, within a range of 5/40 of the total length of the bead to 11/40 of the total length of the bead. Further, the vicinity of 4/5 of the total length of the bead is within the range of 4/5 of the total length of the bead ± 3/40 of the total length of the bead, that is, within the range from 29/40 of the total length of the bead to 35/40 of the total length of the bead. FIG. 3 shows an example in which the vicinity of 1/5 of the total length of the bead is set to 1/5 of the total length of the bead, and the vicinity of 4/5 of the total length of the bead is set to 4/5 of the total length of the bead.
　ビード全長は、レーザビーム３が上側の鋼板４の表面を移動する方向における、ビード始端から終端までの長さである。例えば図３に示すような直線状のビード７では、ビード全長は、ビード始端Ｘとビード終端Ｙとの直線距離であり、ビード７の長手方向の長さである。また、図４に示すようにＣ形状のビード７ａの場合や、図５に示すようにＳ形状のビード７ｂの場合は、ビード全長は、上側の鋼板４の表面における、レーザビーム３の軌跡上のビード始端からビード終端までの長さである。 The total bead length is the length from the bead start to the end in the direction in which the laser beam 3 moves on the surface of the upper steel plate 4. For example, in the linear bead 7 as shown in FIG. 3, the total bead length is a linear distance between the bead start end X and the bead end Y, and is the length of the bead 7 in the longitudinal direction. Further, in the case of the C-shaped bead 7a as shown in FIG. 4 or the S-shaped bead 7b as shown in FIG. 5, the total bead length is on the locus of the laser beam 3 on the surface of the upper steel plate 4. This is the length from the beginning of the bead to the end of the bead.
　このように、式（１）を満たす、すなわち、溶接終了付近の特定範囲の溶接（終期溶接Ｓｆ）におけるレーザ出力Ｐｆを、それより前の溶接（初期溶接Ｓｉおよび本溶接Ｓ）におけるレーザ出力Ｐに対して特定の範囲内の値にすることにより、ビード終端側での割れの発生を抑制することができる。ここで、終期溶接Ｓｆで形成される、ビード始端Ｘからビード全長の４／５の位置近傍～ビードの終端Ｙまで、すなわち、ビード終端Ｙからビード全長の１／５の位置であるビード終端１／５部近傍までのビード７には、隙間Ａがあることにより発生する割れが集中しやすいが、この割れが生じやすい箇所を上記式（１）を満たす条件で溶接することにより、割れの発生を抑制することができる。なお、上記式（１）を満たす溶接工程が、ビード終端Ｙからビード全長の１／５近傍よりも短い場合は、本発明に比べて割れの発生を抑制する効果は小さくなり、また、ビード幅が広がったり、割れが生じるという不具合が生じる。一方、ビード終端Ｙからビード全長の１／５近傍よりも長い場合は、ビード幅が狭くなり、溶接継手強度が低くなるという不具合が生じる。 As described above, the laser output P f in the welding (final welding S f ) in a specific range near the end of the welding that satisfies the expression (1) is the same as that in the previous welding (the initial welding S i and the main welding S). By setting the value within a specific range with respect to the laser output P, it is possible to suppress the occurrence of cracks on the bead end side. Here, formed at the end welding S f, from the bead start X to the end Y position near-bead 4/5 of bead full-length, i.e., the bead end a position of 1/5 of the bead total length from the bead end Y In the bead 7 up to the vicinity of 1/5 part, cracks generated due to the presence of the gap A tend to concentrate. However, by welding a place where this crack is likely to occur under the condition satisfying the above formula (1), Occurrence can be suppressed. In addition, when the welding process which satisfy | fills said Formula (1) is shorter than 1/5 vicinity of bead full length from bead end Y, the effect which suppresses generation | occurrence | production of a crack becomes small compared with this invention, and bead width | variety This causes the problem of spreading or cracking. On the other hand, when it is longer than the vicinity of 1/5 of the total length of the bead from the bead end Y, there arises a problem that the bead width becomes narrow and the weld joint strength becomes low.
　また、式（１）を満たすと割れの発生が抑制されるため、剥離強度が高く安全性に優れたレーザ溶接継手となる。 Also, if the expression (1) is satisfied, the generation of cracks is suppressed, so that a laser welded joint having high peel strength and excellent safety is obtained.
　また、上記条件で溶接を行うことにより、ビード幅を均一にすることができる。例えば、ビード始端Ｘからビート全長の１／５の位置であるビード始端１／５部近傍と、ビード終端Ｙからビード全長の１／５の位置であるビード終端１／５部近傍との間をビード本体Ｂ、ビード本体Ｂのビード幅をＷとし、ビード終端Ｙからビード全長の１／１０の位置をビード終端１／１０部Ｂｆ、ビード終端１／１０部Ｂｆでのビード幅をＷｆとしたときに、下記式（３）を満たすことができる。なお、ビード本体Ｂは本溶接Ｓで形成されるビードであり、安定した溶接が行われて形成されるため、割れは生じず且つビード幅Ｗは均一である。 Further, by performing welding under the above conditions, the bead width can be made uniform. For example, between the bead start end X and the vicinity of 1/5 part of the bead start position, which is 1/5 of the total beat length, and the bead end Y, between the vicinity of the bead end 1/5 part, which is 1/5 of the bead total length. The bead width of the bead main body B and the bead main body B is W, the bead end 1/10 part B f is located at 1/10 of the total length of the bead from the bead end Y, and the bead width at the bead end 1/10 part B f is W When f , the following formula (3) can be satisfied. The bead body B is a bead formed by the main welding S and is formed by performing stable welding, so that no cracks occur and the bead width W is uniform.
　また、上記と同様に、ビード始端Ｘからビート全長の１／５の位置であるビード始端１／５部近傍とは、ビード始端Ｘからビート全長の１／５の位置であるビード始端１／５部±ビード全長の３／４０の範囲内、すなわち、ビード始端Ｘからビート全長の５／４０の位置～ビード始端Ｘからビード全長の１１／４０の位置の範囲内である。また、ビード終端Ｙからビード全長の１／５の位置であるビード終端１／５部近傍とは、ビード終端Ｙからビード全長の１／５の位置であるビード終端１／５部±ビード全長の３／４０の範囲内、すなわち、ビード終端Ｙからビート全長の５／４０の位置～ビード終端Ｙからビード全長の１１／４０の位置の範囲内である。
0.80≦Ｗｆ／Ｗ≦1.20　　(3)
　一方、式（１）を満たさない場合は、ビード終端側で、割れが生じたり、ビード幅が太くなったり細くなったりする。 Similarly to the above, the vicinity of the bead start end 1/5 portion, which is 1/5 of the beat total length from the bead start end X, is the bead start end 1/5, which is 1/5 of the beat total length from the bead start end X. Part ± 3/40 of the total bead length, that is, within the range of 5/40 of the beat total length from the bead starting end X to 11/40 of the total bead length from the bead starting end X. Further, the vicinity of the bead end 1/5 portion, which is 1/5 of the total bead length from the bead end Y, means that the bead end 1/5 portion which is 1/5 of the total bead length from the bead end Y ± the total bead length. It is within the range of 3/40, that is, within the range from 5/40 of the beat total length to the bead end Y to 11/40 of the bead full length from the bead end Y.
0.80 ≦ W f /W≦1.20 (3)
On the other hand, when the formula (1) is not satisfied, cracks occur on the bead end side, and the bead width becomes thicker or thinner.
　照射するレーザビーム３は特に限定されず、例えばファイバーレーザ、ディスクレーザ等を用いることができる。レーザビームは、例えば、ビーム径：０．２～１．０ｍｍ、焦点位置：鋼板４の表面～鋼板４の表面から３０ｍｍ上方とすることができる。入熱効率を高くするために、焦点位置を鋼板４の表面とすることが好ましい。 The laser beam 3 to be irradiated is not particularly limited, and for example, a fiber laser, a disk laser, or the like can be used. The laser beam can be, for example, a beam diameter: 0.2 to 1.0 mm, and a focal position: 30 mm above the surface of the steel plate 4 to the surface of the steel plate 4. In order to increase the heat input efficiency, the focal position is preferably the surface of the steel plate 4.
　初期溶接Ｓｉおよび本溶接Ｓでのレーザ出力Ｐは、例えば２．０ｋＷ以上５．０ｋＷ以下であり、３．０ｋＷ以上４．０ｋＷ以下が好ましい。レーザ出力Ｐが２．０ｋＷ以上であると、レーザ出力が低すぎることがないため、貫通溶接が可能となる。一方、レーザ出力Ｐが５．０ｋＷ以下であると、レーザ出力が高すぎることがないため、溶融金属がスパッタとして飛散して溶接部にアンダーフィルが発生することがない。なお、初期溶接Ｓｉおよび本溶接Ｓでのレーザ出力Ｐが２．０ｋＷ以上５．０ｋＷ以下で且つＰｆが式（１）を満たすと、他のレーザ溶接条件にも依るが、形成されるビート７が鋼板４を貫通しなかったり、ビード７が溶け落ちるという問題も全く生じない。 Initial welding S i and the laser output P in this welding S is, for example, 2.0kW or 5.0kW or less, preferably more than 3.0 kW 4.0 kW. When the laser output P is 2.0 kW or more, the laser output is not too low, and through welding is possible. On the other hand, when the laser output P is 5.0 kW or less, the laser output does not become too high, so that the molten metal is scattered as spatter and the underfill does not occur in the weld. In addition, when the laser output P in the initial welding S i and the main welding S is 2.0 kW or more and 5.0 kW or less and P f satisfies the formula (1), it is formed depending on other laser welding conditions. There is no problem that the beat 7 does not penetrate the steel plate 4 or the beads 7 melt.
　本溶接Ｓおよび終期溶接Ｓｆでの溶接速度ｖは、例えば、１．０ｍ／ｍｉｎ以上４．０ｍ／ｍｉｎ以下、好ましくは２．０ｍ／ｍｉｎ以上３．０ｍ／ｍｉｎ以下である。溶接速度ｖが１．０ｍ／ｍｉｎ以上とすると、溶接速度が遅すぎることがないため、鋼板が融け落ちて欠陥となってしまう場合がない。一方、ｖを４．０ｍ／ｍｉｎ以下とすると溶接速度が速すぎることがないため、溶融池が安定しなくなってしまう場合がない。 Welding speed v at present welded S and final welding S f is, for example, 1.0 m / min or more 4.0 m / min or less, preferably 2.0 m / min or more 3.0 m / min or less. If the welding speed v is 1.0 m / min or more, the welding speed will not be too slow, so the steel sheet will not melt and become a defect. On the other hand, if v is 4.0 m / min or less, the welding speed will not be too fast, and the molten pool will not become stable.
　初期溶接Ｓｉでの溶接速度ｖｉ（ｍ／ｍｉｎ）は特に限定されず、例えば本溶接Ｓおよび終期溶接Ｓｆでの溶接速度ｖと同じでもよいが、初期溶接Ｓ１での溶接速度ｖｉは下記式（２）を満たすことが好ましい。
０．７５((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ＜ｖｉ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ　　(2)
ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａである。 The welding speed v i (m / min) in the initial welding S i is not particularly limited, and may be the same as the welding speed v in the main welding S and the final welding S f , for example, but the welding speed v in the initial welding S 1. i preferably satisfies the following formula (2).
0.75 ((t 1 + t 2 ) / (K + t 1 + t 2)) v <v i <((t 1 + t 2) / (K + t 1 + t 2)) v (2)
However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) is a.
　ビード始端側（初期溶接Ｓ１で形成されるビード）のビード幅は、本溶接Ｓで形成されるビード本体Ｂのビード幅よりも細くなる傾向があり、従来はビード７全体に亘って均一なビード幅を有するものは得難かった。しかしながら、本発明においては、上記式（２）を満たす、すなわち、溶接開始付近の特定範囲の溶接（初期溶接Ｓｉ）における溶接速度ｖｉを、それより後の溶接（本溶接Ｓおよび終期溶接Ｓｆ）の溶接速度ｖに対して特定の範囲内の値にすることにより、ビード始端側でビード幅が細くなる現象を抑制することができる。ビード始端Ｘからビード全長の１／５近傍までのビード７には、隙間Ａがあることによりビード本体Ｂよりもビード幅が細くなりやすいが、このビード幅が細くなりやすい箇所を上記式（２）を満たす条件で溶接することにより、ビード本体Ｂと同程度のビード幅にすることができ、ビード幅をビード全体に亘って均一にすることができる。なお、上記式（２）を満たす溶接工程が、ビード始端Ｘからビード全長の１／５の位置近傍までよりも短い場合や長い場合は、上記式（２）を満たす場合と比べてビード幅を均一にする効果は小さくなる。 Bead width of the bead start end (bead formed in the initial welding S 1) tend to be thinner than the bead width of the bead body B formed in this welding S, conventionally uniform throughout the bead 7 Those having a bead width were difficult to obtain. However, in the present invention, the above-described equation (2) is satisfied, that is, the welding speed v i in a specific range of welding (initial welding S i ) near the start of welding is set to the subsequent welding (main welding S and final welding). By making the value within a specific range with respect to the welding speed v of S f ), the phenomenon that the bead width becomes narrow at the bead start end side can be suppressed. The bead 7 from the bead starting end X to the vicinity of 1/5 of the total length of the bead tends to be narrower than the bead body B due to the gap A, but the portion where the bead width tends to be narrowed is expressed by the above formula (2 ) Can be made to have the same bead width as the bead body B, and the bead width can be made uniform over the entire bead. In addition, when the welding process which satisfy | fills said Formula (2) is shorter or longer than from the bead starting end X to the position vicinity of 1/5 of the bead full length, bead width is set compared with the case where said Formula (2) is satisfy | filled. The effect of making uniform becomes small.
　上記式（２）を満たすことにより、例えば、ビード始端Ｘからビート全長の１／１０の位置をビード始端１／１０部Ｂｉとし、ビード始端１／１０部Ｂｉでのビード幅をＷｉとしたときに、下記式（４）を満たすことができる。例えば式（３）および式（４）を同時に満たすことにより、ビード全体に亘って幅が均一なビードになり、外観に優れたレーザ溶接継手を製造することができる。
0.80≦Ｗｉ／Ｗ≦1.20　　(4)
　一方、式（２）を満たさない場合は、ビード始端側でビードが細くなったり太くなったりする。 By satisfying the above expression (2), for example, 1/10 position of the beat full length and bead starting 1/10 parts B i from the bead starting X, the bead width at the bead beginning 1/10 parts B i W i The following formula (4) can be satisfied. For example, by satisfy | filling Formula (3) and Formula (4) simultaneously, it becomes a bead with a uniform width | variety over the whole bead, and the laser welded joint excellent in the external appearance can be manufactured.
0.80 ≦ W i /W≦1.20 (4)
On the other hand, when the formula (2) is not satisfied, the bead becomes thinner or thicker at the bead start end side.
　なお、レーザ溶接継手に複数のビードが形成される場合は、全てのビードにおいて、ビードを形成する溶接条件が式（１）や式（２）を満たすことが好ましい。また、得られたレーザ溶接継手に形成された全てのビードが式（３）や式（４）を満たすことが好ましい。 In addition, when a some bead is formed in a laser welding joint, it is preferable that the welding conditions which form a bead satisfy | fill Formula (1) and Formula (2) in all the beads. Moreover, it is preferable that all the beads formed in the obtained laser welded joint satisfy Expression (3) and Expression (4).
　上記レーザ溶接継手は、自動車用骨格部品として用いることができる。すなわち、本発明の自動車用骨格部品は、２枚の鋼板４および鋼板５として、それぞれ、引張強度が９８０ＭＰａ以上の高張力鋼板を用いた上記本発明のレーザ溶接継手である。また、本発明の自動車用骨格部品は、２枚の鋼板４および鋼板５として、質量％で、Ｃ：０．０７％超え０．２５％以下、Ｐ＋Ｓ：０．０３％未満、Ｍｎ：１．８％以上３．０％以下、Ｓｉ：１．２％超え１．８％以下を含有し、上記Ａ群および上記Ｂ群の少なくとも一方を含有し、残部がＦｅおよび不可避的不純物からなる成分組成を有し、板厚が１．０ｍｍ以上２．０ｍｍ以下（さらに好ましくは、１．２ｍｍ以上１．８ｍｍ以下）のものを用いたものであることが好ましい。このような本発明の自動車用骨格部品は、高強度で且つ外観に優れているため、センターピラーに適用することができる。センターピラーでは、剥離強度を確保することが重要であり、本発明の自動車用骨格部品を適用したセンターピラーは、十分な剥離強度を有する。 The above laser welded joint can be used as a framework component for automobiles. That is, the automotive framework component of the present invention is the laser welded joint of the present invention using high strength steel plates having a tensile strength of 980 MPa or more as the two steel plates 4 and 5 respectively. In addition, the automobile frame part of the present invention, as two steel plates 4 and 5, is C: 0.07% to 0.25% or less, P + S: less than 0.03%, Mn: 1. Component composition containing 8% or more and 3.0% or less, Si: more than 1.2% and 1.8% or less, containing at least one of group A and group B, with the balance being Fe and inevitable impurities And having a plate thickness of 1.0 mm or more and 2.0 mm or less (more preferably, 1.2 mm or more and 1.8 mm or less). Such an automobile skeletal component of the present invention can be applied to a center pillar because of its high strength and excellent appearance. In the center pillar, it is important to ensure the peel strength, and the center pillar to which the automobile frame component of the present invention is applied has a sufficient peel strength.
　以下に、本発明の更なる理解のために実施例を用いて説明するが、実施例はなんら本発明を限定するものではない。 Hereinafter, examples will be described for further understanding of the present invention, but the examples do not limit the present invention.
　（本発明例および比較例）
　レーザ溶接する鋼板として、鋼種Ｉ（引張強さが９８３ＭＰａ、成分組成が質量％でＣ：０．１３％、Ｓｉ：１．４０％、Ｍｎ：２．２％、Ｐ：０．０１５％、Ｓ：０．００２％、Ｔｉ：０．００５％、Ｃｒ：０．０２１％、Ｍｏ：０．００４％、Ｂ：０．０００２％）または鋼種II（引張強さが１１８４ＭＰａ、成分組成が質量％でＣ：０．１３％、Ｓｉ：１．４０％、Ｍｎ：２．２％、Ｐ：０．０１２％、Ｓ：０．００１％、Ｔｉ：０．００５％、Ｃｒ：０．０１７％、Ｍｏ：０．００４％、Ｂ：０．０００３％）で、板厚が１．６ｍｍまたは１．８ｍｍで幅が５０ｍｍの鋼板を用いた。なお、引張強さは、各鋼板から、圧延方向に対して平行方向にＪＩＳ５号引張試験片を作製し、ＪＩＳ　Ｚ　２２４１：２０１１の規定に準拠して引張試験を実施して求めた引張強度である。 (Invention Example and Comparative Example)
As a steel plate to be laser welded, steel type I (tensile strength is 983 MPa, component composition is mass%, C: 0.13%, Si: 1.40%, Mn: 2.2%, P: 0.015%, S : 0.002%, Ti: 0.005%, Cr: 0.021%, Mo: 0.004%, B: 0.0002%) or steel type II (tensile strength is 1184 MPa, component composition is mass%) C: 0.13%, Si: 1.40%, Mn: 2.2%, P: 0.012%, S: 0.001%, Ti: 0.005%, Cr: 0.017%, Mo : 0.004%, B: 0.0003%), and a steel plate having a plate thickness of 1.6 mm or 1.8 mm and a width of 50 mm was used. The tensile strength is the tensile strength obtained by preparing a JIS No. 5 tensile specimen from each steel plate in a direction parallel to the rolling direction and conducting a tensile test in accordance with the provisions of JIS Z 2241: 2011. is there.
　この鋼板をＬ字の断面形状に曲げ加工を施してフランジ部を有する鋼板４を作製した。同じ鋼種・同じ板厚のＬ字の鋼板５を、実施例および比較例の試験片を示す斜視図である図６に示すように、隙間Ａを空けて重ね合わせた状態で拘束治具に固定した後、フランジの重ね合わせ部分を長手方向にレーザ溶接し、レーザ溶接後拘束治具をはずして、試験片幅５０ｍｍ、横壁長さ１２０ｍｍ、フランジ幅３０ｍｍのＬ字の試験片（レーザ溶接継手）を作製した。 The steel plate 4 having a flange portion was produced by bending the steel plate into an L-shaped cross-sectional shape. An L-shaped steel plate 5 having the same steel type and the same plate thickness is fixed to a restraining jig in a state of being overlapped with a gap A as shown in FIG. 6 which is a perspective view showing test pieces of Examples and Comparative Examples. After that, the overlapped part of the flange is laser welded in the longitudinal direction, and after the laser welding, the restraining jig is removed, and an L-shaped test piece (laser welded joint) having a test piece width of 50 mm, a lateral wall length of 120 mm, and a flange width of 30 mm. Was made.
　この際、レーザ溶接条件を、レーザ溶接前の鋼板４と鋼板５のフランジの重ね合わせ部分の隙間Ａの大きさａ、本溶接Ｓおよび終期溶接Ｓｆの溶接速度ｖ、初期溶接Ｓｉおよび本溶接Ｓのレーザ出力Ｐ、初期溶接Ｓｉの溶接速度ｖｉ、終期溶接Ｓｆのレーザ出力Ｐｆを、表１に示すように種々変えて行った。本発明例および比較例では、ビード全長の１／５近傍をビード全長の１／５とし、また、ビード全長の４／５近傍をビード全長の４／５とした。すなわち、ビード始端Ｘからビード全長の１／５までビードを形成する工程を初期溶接Ｓｉ、初期溶接Ｓｉに続いてビード全長の４／５までビードを形成する工程を本溶接Ｓ、本溶接Ｓに続いてビード終端Ｙまでビードを形成する工程を終期溶接Ｓｆとした。なお、レーザ溶接前のフランジの重ね合わせ部分の隙間Ａの大きさａは、レーザ溶接方向に亘って均一であった。 At this time, the laser welding conditions, the gap A of the flange superposition portion of the steel plate 4 and the steel plate 5 before laser welding the size a, the weld S and final welding S f of welding speed v, the initial welding S i and the laser power P of the welding S, initial welding S i welding speed v i of the laser output P f of the final weld S f, was performed variously changed as shown in Table 1. In the present invention example and the comparative example, the vicinity of 1/5 of the total length of the bead was set to 1/5 of the total length of the bead, and the vicinity of 4/5 of the total length of the bead was set to 4/5 of the total length of the bead. That is, the process of forming the bead from the bead starting end X to 1/5 of the total length of the bead is the initial welding S i , and the process of forming the bead to 4/5 of the total length of the bead following the initial welding S i is the main welding S and the main welding. a step subsequent to S to form a bead to bead end Y was final weld S f. In addition, the magnitude | size a of the clearance gap A of the overlapping part of the flange before laser welding was uniform over the laser welding direction.
　レーザ溶接にはファイバーレーザを用い、焦点位置のビーム直径を０．６ｍｍφの一定とした。溶接は大気中で行い、レーザ溶接時の焦点位置は、鋼板４のフランジ部の鋼板表面とした。 フ ァ イ バ ー Fiber laser was used for laser welding, and the beam diameter at the focal position was fixed at 0.6 mmφ. Welding was performed in the atmosphere, and the focal position during laser welding was the steel plate surface of the flange portion of the steel plate 4.
　得られたＬ字のレーザ溶接継手のビードの外観を観察した結果を表１に示す。具体的には、ビードの割れの有無を、目視により観察した。また、ビード本体Ｂのビード幅Ｗ、ビード始端１／１０部Ｂｉでのビード幅Ｗｉ、および、ビード終端１／１０部Ｂｆでのビード幅Ｗｆを測定し、ビード幅比Ｗｉ／ＷおよびＷｆ／Ｗを求めた。なお、本発明例および比較例においては、ビード本体Ｂは、ビード始端Ｘからビート全長の１／５の位置であるビード始端１／５部とビード終端Ｙからビード全長の１／５の位置であるビード終端１／５部との間である。そして、式（３）および式（４）の両方を満たす場合を「○」、式（３）および式（４）のいずれか一方を満たす場合を「△」、式（３）および式（４）のいずれも満たさない場合を「×」として、ビード幅の均一性を評価した。なお、ビード本体Ｂの幅Ｗは、いずれのレーザ溶接継手においてもビード本体Ｂ全体に亘って一定であった。また、レーザ溶接継手の隙間の大きさはビード始端Ｘからビード全長方向に５ｍｍ離れた位置とビード終端Ｙからビード全長方向に５ｍｍ離れた位置の隙間の大きさを測定し、その平均値を求めた。 Table 1 shows the results of observation of the appearance of the beads of the obtained L-shaped laser welded joint. Specifically, the presence or absence of cracks in the beads was visually observed. Further, the bead width W of the bead body B, the bead width W i in the bead beginning 1/10 parts B i, and measures the bead width W f in bead termination 1/10 parts B f, the bead width ratio W i / W and W f / W were determined. In the present invention example and the comparative example, the bead main body B is located at 1/5 of the bead start end, which is 1/5 of the total beat length from the bead start end X, and at 1/5 of the bead total length from the bead end Y. Between the bead end 1/5 part. And when satisfy | filling both Formula (3) and Formula (4), it is "(circle)", and when satisfy | filling either one of Formula (3) and Formula (4), it is "(triangle | delta)", Formula (3), and Formula (4) The case where none of the above was satisfied was evaluated as “x”, and the uniformity of the bead width was evaluated. In addition, the width W of the bead body B was constant over the entire bead body B in any laser weld joint. Also, the size of the gap of the laser welded joint is measured by measuring the size of the gap at a position 5 mm away from the bead starting end X in the bead full length direction and a position 5 mm away from the bead end Y in the bead full length direction. It was.
　また、得られたＬ字のレーザ溶接継手の隙間の、鋼板の板厚方向の大きさを測定した。 Also, the size of the gap between the obtained L-shaped laser welded joints in the thickness direction of the steel sheet was measured.
　また、得られたＬ字のレーザ溶接継手に対して、両側から引張荷重を負荷するＬ字引張試験にて、剥離強度を測定した。なお、引張試験は１０ｍｍ／ｍｉｎの速度で行った。結果を表１に示す。 Also, the peel strength of the obtained L-shaped laser welded joint was measured by an L-shaped tensile test in which a tensile load was applied from both sides. The tensile test was performed at a speed of 10 mm / min. The results are shown in Table 1.
　表１に示すように、式（１）を満たす溶接条件で行った本発明例は、ビード終端部等ビード全体に亘って割れが無く、また、ビード幅比Ｗｆ／Ｗも０．８０以上１．２０以下であり、外観が優れていた。そして、式（１）を満たす溶接条件で行った本発明例は、剥離強度が４．０ｋＮ以上であり、高強度接合されていた。また、特に、式（１）および式（２）の両方を満たす本発明例は、ビード幅比Ｗｉ／Ｗも０．８０以上１．２０以下であり、ビード全長に亘って均一な幅を有していた。 As shown in Table 1, the example of the present invention performed under the welding conditions satisfying the formula (1) has no cracks throughout the bead such as the bead end portion, and the bead width ratio W f / W is 0.80 or more. It was 1.20 or less, and the appearance was excellent. And the example of this invention performed on the welding conditions which satisfy | fill Formula (1) has a peeling strength of 4.0 kN or more, and was joined by high intensity | strength. In particular, in the present invention example satisfying both the formulas (1) and (2), the bead width ratio W i / W is also 0.80 or more and 1.20 or less, and the bead width ratio is uniform over the entire length of the bead. Had.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　１　レーザ溶接継手
　３　レーザビーム
　４、５　鋼板
　７、７ａ、７ｂ　ビード
　Ａ　隙間
　Ｂ　ビード本体
　Ｓｉ　初期溶接
　Ｓ　本溶接
　Ｓｆ　終期溶接
　Ｗ　ビード幅
　Ｘ　ビード始端
　Ｙ　ビード終端
  First laser weld joint 3 laser beams 4, 5 steel 7, 7a, 7b bead A clearance B bead body S i initial welding S present welding S f final weld W bead width X bead start Y bead termination

Claims (6)

  1. 　２枚の鋼板をその間に隙間を有するように上下に重ね合わせた状態でレーザビームを上側の鋼板表面に照射してレーザビームが照射された部位を溶融および凝固させてビードを形成すると共に２枚の鋼板を接合するレーザ溶接により２枚の鋼板が接合されたレーザ溶接継手を得るレーザ溶接継手の製造方法であって、
    　上側の鋼板の板厚をｔ１（ｍｍ）、下側の鋼板の板厚をｔ２（ｍｍ）、上側の鋼板と下側の鋼板との隙間の大きさをａ（ｍｍ）とし、
    ビード始端からビード全長の１／５近傍までビードを形成する工程を初期溶接、該初期溶接に続いてビード全長の４／５近傍までビードを形成する工程を本溶接、該本溶接に続いてビード終端までビードを形成する工程を終期溶接とし、
    前記初期溶接および前記本溶接でのレーザ出力をＰ（ｋＷ）、前記終期溶接でのレーザ出力をＰｆ（ｋＷ）としたときに、
    下記式（１）を満たすことを特徴とするレーザ溶接継手の製造方法。
    ０．８((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ＜Ｐｆ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))Ｐ　(1)
    ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａ　（単位：ｍｍ）である。     The two steel plates are superposed one above the other with a gap between them, and a laser beam is irradiated on the upper steel plate surface to melt and solidify the portion irradiated with the laser beam to form a bead and two A method of manufacturing a laser welded joint, which obtains a laser welded joint in which two steel plates are joined by laser welding for joining the steel plates of
    The plate thickness of the upper steel plate is t 1 (mm), the plate thickness of the lower steel plate is t 2 (mm), the size of the gap between the upper steel plate and the lower steel plate is a (mm),
    Initial welding is the process of forming a bead from the beginning of the bead to the vicinity of 1/5 of the total length of the bead. The initial welding is followed by the process of forming the bead to the vicinity of 4/5 of the total length of the bead. The process of forming the bead to the end is the final welding,
    When the laser output in the initial welding and the main welding is P (kW), and the laser output in the final welding is P f (kW),
    The manufacturing method of the laser welded joint characterized by satisfy | filling following formula (1).
    0.8 ((t 1 + t 2 ) / (K + t 1 + t 2 )) P <P f <((t 1 + t 2 ) / (K + t 1 + t 2 )) P (1)
    However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) a ( unit: mm) is.
  2. 　前記本溶接および前記終期溶接での溶接速度をｖ（ｍ／ｍｉｎ）、前記初期溶接での溶接速度をｖｉ（ｍ／ｍｉｎ）としたときに、
    下記式（２）を満たすことを特徴とする請求項１に記載するレーザ溶接継手の製造方法。
    ０．７５((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ＜ｖｉ＜((ｔ１＋ｔ２)／(Ｋ＋ｔ１＋ｔ２))ｖ　(2)
    ただし、ａは０．５ｔ１と０．５ｔ２のうちの小さい方以下であり、Ｋ＝（ｔ２／ｔ１）ａである。     When the welding speed in the main welding and the final welding is v (m / min), and the welding speed in the initial welding is v i (m / min),
    The method for manufacturing a laser welded joint according to claim 1, wherein the following formula (2) is satisfied.
    0.75 ((t 1 + t 2 ) / (K + t 1 + t 2)) v <v i <((t 1 + t 2) / (K + t 1 + t 2)) v (2)
    However, a is less than the smaller of the 0.5 t 1 and 0.5t 2, K = (t 2 / t 1) is a.
  3. 　２枚の鋼板からなるレーザ溶接継手であって、
    前記２枚の鋼板の間に隙間を有し、
    前記隙間の大きさが、２枚の鋼板のうち薄い方の板厚の１０％～５０％であり、
    前記２枚の鋼板のうち上側の鋼板表面に形成されたビードが、
    ビード始端からビート全長の１／５の位置であるビード始端１／５部近傍と、ビード終端からビード全長の１／５の位置であるビード終端１／５部近傍と、の間をビード本体とし、
    ビード終端からビード全長の１／１０の位置をビード終端１／１０部とし、
    ビード本体のビード幅をＷ、ビード終端１／１０部でのビード幅をＷｆとしたときに、
    下記式（３）を満たすことを特徴とするレーザ溶接継手。
    0.80≦Ｗｆ／Ｗ≦1.20　　(3)     A laser welded joint made of two steel plates,
    Having a gap between the two steel plates,
    The size of the gap is 10% to 50% of the thinner one of the two steel plates,
    A bead formed on the upper steel plate surface of the two steel plates,
    The bead body is between the bead start end 1/5 portion, which is 1/5 of the total beat length from the bead start end, and the bead end 1/5 portion, which is 1/5 of the bead end length, from the bead end. ,
    The position of 1/10 of the total length of the bead from the end of the bead is 1/10 part of the bead end,
    When the bead width of the bead body is W and the bead width at the bead end 1/10 part is W f ,
    A laser welded joint satisfying the following formula (3).
    0.80 ≦ W f /W≦1.20 (3)
  4. 　ビード始端からビート全長の１／１０の位置をビード始端１／１０部とし、
    ビード始端１／１０部でのビード幅をＷｉとしたときに、
    下記式（４）を満たすことを特徴とする請求項３に記載するレーザ溶接継手。
    0.80≦Ｗｉ／Ｗ≦1.20　　(4)     The position of 1/10 of the beat total length from the bead start end is 1/10 part of the bead start end,
    A bead width at the bead beginning 1/10 parts when the W i,
    The laser weld joint according to claim 3, wherein the following formula (4) is satisfied.
    0.80 ≦ W i /W≦1.20 (4)
  5. 　請求項３または４に記載するレーザ溶接継手を有し、前記２枚の鋼板はそれぞれ引張強度が９８０ＭＰａ以上の高強度鋼板であることを特徴とする自動車用骨格部品。 5. A framework part for an automobile having the laser welded joint according to claim 3 or 4, wherein each of the two steel plates is a high strength steel plate having a tensile strength of 980 MPa or more.
  6. 　前記２枚の鋼板は、それぞれ、質量％で、Ｃ：０．０７％超え０．２５％以下、Ｐ＋Ｓ：０．０３％未満、Ｍｎ：１．８％以上３．０％以下、Ｓｉ：１．２％超え１．８％以下を含有し、下記Ａ群および下記Ｂ群の少なくとも一方を含有し、残部がＦｅおよび不可避的不純物からなる成分組成を有し、板厚が１．０ｍｍ以上２．０ｍｍ以下であることを特徴とする請求項５に記載する自動車用骨格部品。
    Ａ群：　Ｔｉ：０．００５％以上０．０１０％以下およびＮｂ：０．００５％以上０．０５０％未満の少なくとも一方
    Ｂ群：　Ｃｒ：１．０％以下、Ｍｏ：０．５０％以下およびＢ：０．１０％以下から選択される少なくとも一種
          The two steel sheets are each in mass%, C: more than 0.07% and 0.25% or less, P + S: less than 0.03%, Mn: 1.8% or more and 3.0% or less, Si: 1 .2% to 1.8% or less, at least one of the following group A and group B, the balance being a component composition consisting of Fe and inevitable impurities, and a plate thickness of 1.0 mm to 2 The automobile frame part according to claim 5, wherein the frame part is 0.0 mm or less.
    Group A: Ti: 0.005% or more and 0.010% or less and Nb: 0.005% or more and less than 0.050% Group B: Cr: 1.0% or less, Mo: 0.50% or less and B: At least one selected from 0.10% or less
PCT/JP2017/029899 2016-09-29 2017-08-22 Method of manufacturing laser welded joint, laser welded joint, and automotive frame component WO2018061526A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
CN202011472962.9A CN112743228B (en) 2016-09-29 2017-08-22 Laser welded joint and automobile frame part
KR1020207033067A KR102412797B1 (en) 2016-09-29 2017-08-22 Laser welded joint and auto-motive frame component
KR1020217024757A KR102425207B1 (en) 2016-09-29 2017-08-22 Laser welded joint and auto-motive frame component
KR1020197004575A KR102184912B1 (en) 2016-09-29 2017-08-22 Manufacturing method of laser welding joint, laser welding joint and skeleton parts for automobiles
JP2017562099A JP6662396B2 (en) 2016-09-29 2017-08-22 Manufacturing method of laser welded joint
CN201780050173.6A CN109641321B (en) 2016-09-29 2017-08-22 Method for manufacturing laser welded joint and laser welded joint

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016192071 2016-09-29
JP2016-192071 2016-09-29

Publications (1)

Publication Number Publication Date
WO2018061526A1 true WO2018061526A1 (en) 2018-04-05

Family

ID=61762843

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/029899 WO2018061526A1 (en) 2016-09-29 2017-08-22 Method of manufacturing laser welded joint, laser welded joint, and automotive frame component

Country Status (4)

Country Link
JP (1) JP6662396B2 (en)
KR (3) KR102184912B1 (en)
CN (2) CN109641321B (en)
WO (1) WO2018061526A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6583657B1 (en) * 2019-03-28 2019-10-02 Ｊｆｅスチール株式会社 Lap laser welded joint, manufacturing method thereof, and structural member for automobile body
JP2019188407A (en) * 2018-04-19 2019-10-31 株式会社神戸製鋼所 Laser welded joint and method for production thereof
JPWO2019225528A1 (en) * 2018-05-21 2020-05-28 Ｊｆｅスチール株式会社 Lap laser welded joint, method for manufacturing lap laser welded joint, and automobile frame component
KR20200075285A (en) * 2018-12-18 2020-06-26 주식회사 포스코 Laser welding method for high carbon thin steel sheet
WO2020194687A1 (en) * 2019-03-28 2020-10-01 Ｊｆｅスチール株式会社 Lap laser spot weld joint and method for producing same, and automotive body structural component
US11738808B2 (en) 2019-04-23 2023-08-29 Arcelormittal Tunnel having integrated lateral reinforcements

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110560876A (en) * 2019-09-23 2019-12-13 南昌航空大学 Double-layer plate with cooling turbulence column structure and vacuum electron beam processing method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010012504A (en) * 2008-07-04 2010-01-21 Sumitomo Metal Ind Ltd Laser beam welding structural member and its manufacturing method
JP2012135794A (en) * 2010-12-27 2012-07-19 Suzuki Motor Corp Laser lap welding method
JP2012170989A (en) * 2011-02-22 2012-09-10 Suzuki Motor Corp Laser lap welding method
WO2015198582A1 (en) * 2014-06-23 2015-12-30 Ｊｆｅスチール株式会社 High-strength steel sheet
JP2016112577A (en) * 2014-12-12 2016-06-23 近畿車輌株式会社 Welding method

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1389011A (en) 1971-04-02 1975-04-03 Ici Ltd Oxochlorination process
JP4017571B2 (en) * 2003-07-02 2007-12-05 大陽日酸株式会社 Laser welding method for steel sheet
JP2006142917A (en) * 2004-11-17 2006-06-08 Nippon Steel Corp Shock absorbing member having excellent shock absorbing property and welding method therefor
JP2007000888A (en) * 2005-06-22 2007-01-11 Nisshin Steel Co Ltd Laser welding method
JP2008142731A (en) * 2006-12-08 2008-06-26 Nissan Motor Co Ltd Laser welding method and equipment, and lap welding joint by laser
JP5267317B2 (en) * 2008-12-09 2013-08-21 新日鐵住金株式会社 Laser lap welded joint of high strength thin steel sheet and manufacturing method thereof
MY182963A (en) * 2009-12-04 2021-02-05 Nippon Steel Corp Butt-weld joint and method for manufacturing same
KR20120079628A (en) * 2011-01-05 2012-07-13 주식회사 세원정공 Car body parts galvanized sheet iron matching laser welding method
KR101272050B1 (en) * 2011-11-11 2013-06-07 주식회사 성우하이텍 Method of laser welding
JP2013215755A (en) 2012-04-05 2013-10-24 Nippon Steel & Sumitomo Metal Corp Laser welding method, lap welded joint, and laser welding equipment
JP2013233557A (en) * 2012-05-08 2013-11-21 Jfe Steel Corp Laser and arc hybrid welding method
BR112015001023A2 (en) * 2012-08-08 2017-06-27 Nippon Steel & Sumitomo Metal Corp welding method of overlapping parts, method of manufacturing welded and overlapping member, welded and overlapping member and automotive part
CN103273199B (en) * 2013-04-07 2017-06-09 深圳市三森科技有限公司 A kind of processing method for improving laser weld strength
JP6203647B2 (en) * 2014-01-21 2017-09-27 株式会社神戸製鋼所 Laser welded joint of high-strength steel sheet and manufacturing method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010012504A (en) * 2008-07-04 2010-01-21 Sumitomo Metal Ind Ltd Laser beam welding structural member and its manufacturing method
JP2012135794A (en) * 2010-12-27 2012-07-19 Suzuki Motor Corp Laser lap welding method
JP2012170989A (en) * 2011-02-22 2012-09-10 Suzuki Motor Corp Laser lap welding method
WO2015198582A1 (en) * 2014-06-23 2015-12-30 Ｊｆｅスチール株式会社 High-strength steel sheet
JP2016112577A (en) * 2014-12-12 2016-06-23 近畿車輌株式会社 Welding method

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019188407A (en) * 2018-04-19 2019-10-31 株式会社神戸製鋼所 Laser welded joint and method for production thereof
JPWO2019225528A1 (en) * 2018-05-21 2020-05-28 Ｊｆｅスチール株式会社 Lap laser welded joint, method for manufacturing lap laser welded joint, and automobile frame component
KR102164134B1 (en) 2018-12-18 2020-10-12 주식회사 포스코 Laser welding method for high carbon thin steel sheet
KR20200075285A (en) * 2018-12-18 2020-06-26 주식회사 포스코 Laser welding method for high carbon thin steel sheet
JPWO2020194687A1 (en) * 2019-03-28 2020-10-01
WO2020194669A1 (en) * 2019-03-28 2020-10-01 Ｊｆｅスチール株式会社 Lap laser welding joint, method for manufacturing same, and automobile chassis structure member
JP6583657B1 (en) * 2019-03-28 2019-10-02 Ｊｆｅスチール株式会社 Lap laser welded joint, manufacturing method thereof, and structural member for automobile body
WO2020194687A1 (en) * 2019-03-28 2020-10-01 Ｊｆｅスチール株式会社 Lap laser spot weld joint and method for producing same, and automotive body structural component
CN113573838A (en) * 2019-03-28 2021-10-29 杰富意钢铁株式会社 Lap laser welded joint, method for manufacturing same, and structural member for automobile body
CN113573837A (en) * 2019-03-28 2021-10-29 杰富意钢铁株式会社 Lap laser spot welded joint, method for manufacturing same, and structural member for automobile body
JP7211491B2 (en) 2019-03-28 2023-01-24 Ｊｆｅスチール株式会社 LAP LASER SPOT WELD JOINT, MANUFACTURING METHOD THEREOF, AND STRUCTURAL MEMBER FOR AUTOMOBILE BODY
CN113573838B (en) * 2019-03-28 2023-06-02 杰富意钢铁株式会社 Overlap laser welded joint, method for producing same, and structural member for automobile body
US11738808B2 (en) 2019-04-23 2023-08-29 Arcelormittal Tunnel having integrated lateral reinforcements

Also Published As

Publication number Publication date
CN109641321A (en) 2019-04-16
CN112743228A (en) 2021-05-04
KR102425207B1 (en) 2022-07-27
KR20190029688A (en) 2019-03-20
KR20200133391A (en) 2020-11-27
KR102412797B1 (en) 2022-06-23
JP6662396B2 (en) 2020-03-11
KR20210099210A (en) 2021-08-11
CN112743228B (en) 2022-11-01
CN109641321B (en) 2021-01-05
JPWO2018061526A1 (en) 2018-09-27
KR102184912B1 (en) 2020-12-01

Similar Documents

Publication Publication Date Title
WO2018061526A1 (en) Method of manufacturing laser welded joint, laser welded joint, and automotive frame component
CA2999105C (en) Laser welding method for producing a semi-finished sheet metal product made of hardenable steel and comprising a coating based on aluminium or aluminium-silicon
KR102088470B1 (en) Method for laser welding one or more workpieces of hardenable steel with a butt joint using a filler wire
CN106475683B (en) A kind of laser assembly solder method with Al-Si coating hot forming steel plate
JP6515299B2 (en) Fillet arc welded joint and method of manufacturing the same
JP2013533807A (en) Hybrid arc / laser welding process for aluminized steel parts using gammagenic elements and a gas containing less than 10% nitrogen or oxygen
JP6443319B2 (en) Lap laser spot welded joint and method of manufacturing the welded joint
KR20180114122A (en) Overlap laser welded joint, method of manufacturing the welded joint, and skeleton part for automobile
JP6635235B1 (en) Lap laser welded joint, manufacturing method of lap laser welded joint, and skeletal parts for automobile
WO2022165997A1 (en) Method for laser powder-filling welding and heat treatment of coated steel
US20220258283A1 (en) Method for producing a coated tailored welded blank by means of laser-beam welding or hybrid laser/gas-metal-arc welding and filler wire and use thereof for this purpose
JP7211491B2 (en) LAP LASER SPOT WELD JOINT, MANUFACTURING METHOD THEREOF, AND STRUCTURAL MEMBER FOR AUTOMOBILE BODY
JP2010279991A (en) Method of lap-welding steel sheet by laser beam
JP6583657B1 (en) Lap laser welded joint, manufacturing method thereof, and structural member for automobile body
JP2000015353A (en) Welded joining metallic plate excellent in press formability and production thereof
KR102407608B1 (en) Lap laser welded joint, manufacturing method of lap laser welded joint and skeletal parts for automobiles
JP2005288504A (en) Welded joint excellent in fatigue strength and its welding method
JPH0726346A (en) Cold rolled dead-soft steel sheet excellent in formability after high density energy beam welding and surface treated steel sheet using this cold rolled steel sheet as starting sheet
JP2005271033A (en) Spot welding method of high-strength steel sheet

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2017562099

Country of ref document: JP

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17855484

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20197004575

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17855484

Country of ref document: EP

Kind code of ref document: A1