WO2016080488A1 - レーザー溶接継手、自動車部品、レーザー溶接継手の製造方法および自動車部品の製造方法 - Google Patents
レーザー溶接継手、自動車部品、レーザー溶接継手の製造方法および自動車部品の製造方法 Download PDFInfo
- Publication number
- WO2016080488A1 WO2016080488A1 PCT/JP2015/082553 JP2015082553W WO2016080488A1 WO 2016080488 A1 WO2016080488 A1 WO 2016080488A1 JP 2015082553 W JP2015082553 W JP 2015082553W WO 2016080488 A1 WO2016080488 A1 WO 2016080488A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- weld metal
- welded joint
- weld
- laser
- welding
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 32
- 238000000034 method Methods 0.000 title claims description 24
- 229910052751 metal Inorganic materials 0.000 claims abstract description 312
- 239000002184 metal Substances 0.000 claims abstract description 312
- 238000003466 welding Methods 0.000 claims abstract description 101
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 97
- 239000010959 steel Substances 0.000 claims abstract description 97
- 238000009826 distribution Methods 0.000 claims abstract description 43
- 239000000203 mixture Substances 0.000 claims abstract description 38
- 239000000126 substance Substances 0.000 claims abstract description 26
- 239000001257 hydrogen Substances 0.000 claims description 103
- 229910052739 hydrogen Inorganic materials 0.000 claims description 103
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 100
- 229910000734 martensite Inorganic materials 0.000 claims description 25
- 238000000465 moulding Methods 0.000 claims description 25
- 229910052750 molybdenum Inorganic materials 0.000 claims description 11
- 239000012535 impurity Substances 0.000 claims description 9
- 150000002739 metals Chemical class 0.000 abstract 5
- 238000005336 cracking Methods 0.000 description 30
- 239000000463 material Substances 0.000 description 19
- 230000000694 effects Effects 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 16
- 238000012360 testing method Methods 0.000 description 16
- 229910052761 rare earth metal Inorganic materials 0.000 description 13
- 230000001276 controlling effect Effects 0.000 description 11
- 229910052759 nickel Inorganic materials 0.000 description 10
- 229910052758 niobium Inorganic materials 0.000 description 10
- 229910052804 chromium Inorganic materials 0.000 description 9
- 238000007747 plating Methods 0.000 description 9
- 239000013078 crystal Substances 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 230000007423 decrease Effects 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 229910052719 titanium Inorganic materials 0.000 description 7
- 238000009825 accumulation Methods 0.000 description 6
- 230000003111 delayed effect Effects 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 229910052717 sulfur Inorganic materials 0.000 description 6
- 229910052720 vanadium Inorganic materials 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 5
- 229910001566 austenite Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 230000000717 retained effect Effects 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000010960 cold rolled steel Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 3
- 238000000177 wavelength dispersive X-ray spectroscopy Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000010494 dissociation reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007542 hardness measurement Methods 0.000 description 2
- 238000005304 joining Methods 0.000 description 2
- 229910052747 lanthanoid Inorganic materials 0.000 description 2
- 150000002602 lanthanoids Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 229910018134 Al-Mg Inorganic materials 0.000 description 1
- 229910018467 Al—Mg Inorganic materials 0.000 description 1
- 229910018464 Al—Mg—Si Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910007610 Zn—Sn Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 208000018459 dissociative disease Diseases 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- -1 for example Substances 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B5/00—Joining sheets or plates, e.g. panels, to one another or to strips or bars parallel to them
- F16B5/08—Joining sheets or plates, e.g. panels, to one another or to strips or bars parallel to them by means of welds or the like
-
- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/3073—Fe as the principal constituent with Mn as next major constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/02—Stamping using rigid devices or tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards
-
- 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
- B23K26/21—Bonding by welding
- B23K26/24—Seam welding
- B23K26/26—Seam welding of rectilinear seams
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0255—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0255—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in welding
- B23K35/0261—Rods, electrodes, wires
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
- B23K35/0255—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in welding
- B23K35/0261—Rods, electrodes, wires
- B23K35/0266—Rods, electrodes, wires flux-cored
-
- 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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/3066—Fe as the principal constituent with Ni as next major constituent
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- 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
-
- 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
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- 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
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/006—Vehicles
-
- 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
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Definitions
- the present invention relates to a laser welded joint, an automobile part, a method for producing a laser welded joint, and a process for producing an automobile part.
- a vehicle body has been assembled by joining a plurality of parts obtained by press forming steel plates by spot welding or arc welding.
- tailored blanks see, for example, Non-Patent Document 1
- a tailored blank is a method of press-molding a plate material (hereinafter also referred to as a “tailored blank material”) in which a plurality of metal plates having different materials, plate thicknesses, tensile strengths, and the like are integrated by butt welding.
- Laser welding is generally used for butt welding when manufacturing a tailored blank.
- Non-Patent Document 1 describes that in a tailored blank material manufactured by laser welding, stress concentration due to shrinkage occurs at the beginning or end of welding, and the tailored blank material may break. Yes.
- Non-Patent Document 2 describes that, in the case of arc welding, when hydrogen is present in the weld metal, hydrogen accumulates in a stress concentration portion generated by welding and so-called delayed fracture occurs. It is known that this delayed fracture can be suppressed by preheating before welding or heat treatment after welding.
- Patent Documents 1 to 3 techniques for preventing the occurrence of cracks in welded joints are disclosed in Patent Documents 1 to 3. Specifically, in Patent Document 1, in a welded steel pipe in which the butt portion is arc-welded, the occurrence of hydrogen embrittlement cracking during pipe expansion or contraction correction is suppressed by keeping the hydrogen concentration of the weld metal below a certain value. It describes what you can do.
- Patent Document 2 in a weld metal formed by gas shielded arc welding using a flux-cored wire, the chemical composition is controlled within a predetermined range, and the number density and volume fraction of residual austenite particles are set to a predetermined value or more. It is described that hydrogen embrittlement susceptibility is improved by controlling.
- Patent Document 3 describes that the hydrogen-induced cracking resistance of a steel sheet obtained from a slab can be improved by reducing the porosity volume at the center in the thickness direction of the slab.
- the following phenomenon can be considered as the cause of cracking of the weld metal.
- shrinkage occurs at the start or end of welding. It is considered that residual stress is generated at the starting end portion or the terminal end portion due to this shrinkage, and cracks are generated.
- the lack of the plate thickness of the laser welded portion (weld bead portion) that occurs when the laser welding conditions or the metal plate butt conditions cannot be optimized is also considered to be a cause of cracking.
- a crack may occur, and the cause of the crack cannot be explained only by residual stress and insufficient plate thickness of the laser welded portion.
- Non-Patent Document 2 the delayed fracture described in Non-Patent Document 2 is caused by accumulation of hydrogen, and can be suppressed by preheating before welding or heat treatment after welding.
- cracks that occur in weld metal when press-molding tailored blanks occur during molding in a short time (within a few seconds), and are caused by causes other than delayed fracture caused by hydrogen accumulation. it is conceivable that. Therefore, it is difficult to prevent cracking of the weld metal of the tailored blank material only by preheating before welding or heat treatment after welding.
- Patent Document 1 suppresses the occurrence of hydrogen embrittlement cracks during arc expansion or contraction correction in arc welded steel pipes.
- the influence of hydrogen on cracking of the weld metal is hardly clarified in a large deformation forming mode that involves drawing and bending in a short time, such as press forming of a thin steel plate.
- Laser welding has a different welding mechanism and welding atmosphere from arc welding, and the cause of cracks occurring in the weld metal is hardly quantified, including the hydrogen content.
- Patent Document 2 improves the resistance to hydrogen embrittlement resistance of a weld metal by controlling the number density and volume fraction of retained austenite particles to a predetermined value or more in a weld metal formed using a flux-cored wire.
- a wire is generally not used in order to reduce manufacturing costs.
- it is difficult to control the number density and volume fraction of retained austenite particles as in Patent Document 2 because the structure of the weld metal is determined by the chemical composition of the material to be welded.
- the weld metal is rapidly cooled after the material is melted. Also from this fact, it is substantially difficult to control the number density and volume fraction of retained austenite particles.
- Patent Document 3 improves the hydrogen-induced cracking resistance of the steel sheet by reducing the porosity volume.
- the relationship between the cracks generated in the weld metal during the press forming of the steel sheet and the porosity has not been clarified. For this reason, it is difficult to prevent the crack which generate
- FIG. 1 illustrates the crack which generate
- the present invention has been made to solve the above-described problems, and is capable of suppressing cracks generated in a weld metal during press molding, a laser welded joint, an automobile part, a method for manufacturing the laser welded joint, and the It aims at providing the manufacturing method of a motor vehicle part.
- a first aspect of the present invention is a laser welded joint having a weld metal provided between a plurality of steel plates, wherein the chemical composition of the weld metal is, by mass, C: 0.05 to 0.30%, Si: 0.005 to 3.0%, Al: 0.005 to 1.0%, Mn: 0.5 to 6.0%, P: more than 0 to 0.04%, S: Over 0 to 0.01%, N: Over 0 to 0.01%, O: Over 0 to 0.01%, Cu: 0 to 1.0%, Nb + Ti + V: 0 to 0.2%, Ca + REM: 0 to 0.01%, B: 0 to 0.01%, Cr: 0 to 5.0%, Ni: 0 to 10.0%, Mo: 0 to 1.0%, and the balance: Fe and impurities
- 0.3 ⁇ Si + 200 ⁇ S ⁇ 2.7 ⁇ C ⁇ 3.0 is satisfied, and the average hardness of the weld metal is 350 to 540 in terms of Vic
- the chemical composition of the weld metal is Cu: 0.0001 to 1.0%, Nb + Ti + V: 0.0001 to 0.2%, Ca + REM in mass%. : 0.0001 to 0.01%, B: 0.0001 to 0.01%, Cr: 0.0001 to 5.0%, Ni: 0.0001 to 10.0%, and Mo: 0.0001 to It may include at least one selected from the group of 1.0%.
- C H of the weld metal is, as a unit mass ppm, may satisfy the following equation (a).
- HV WM represents the average hardness of the weld metal in terms of Vickers hardness.
- 80% or more of the metal structure of the weld metal is martensite, and the martensite structure is a bcc structure. May be.
- the value of Ms represented by the following formula (b) may be 250 or more.
- At least one of the plurality of steel plates may be a plated steel plate.
- a second aspect of the present invention is an automotive part having the laser welded joint according to any one of (1) to (6) above.
- a third aspect of the present invention is the method for producing a laser welded joint according to any one of the above (1) to (6), wherein a plurality of steel plates have an absolute humidity of 5 to 25 g /
- a laser welding process for forming a weld metal that joins the plurality of steel plates to each other by laser welding at a welding speed of 8 m / min or less in an atmosphere of m 3 or less;
- a holding step for holding for a time specified by the following formula (c) in a temperature range of ° C., wherein the chemical composition of the weld metal is C: 0.05 to 0.30%, Si: 0.005 to 3.0%, Al: 0.005 to 1.0%, Mn: 0.5 to 6.0%, P: more than 0 to 0.04%, S: more than 0 to 0.01% , N: more than 0 to 0.01%, O: more than 0 to 0.01%, Cu: 0 to 1.0%, Nb + Ti + V: 0 to 0.2 Ca + REM:
- the chemical composition of the weld metal is Cu: 0.0001 to 1.0%, Nb + Ti + V: 0.0001 to 0.2 in mass%. %, Ca + REM: 0.0001 to 0.01%, B: 0.0001 to 0.01%, Cr: 0.0001 to 5.0%, Ni: 0.0001 to 10.0%, and Mo: 0 And at least one selected from the group of .0001 to 1.0%.
- the value of Ms represented by the following formula (d) may be 250 or more.
- At least one of the plurality of steel plates may be a plated steel plate.
- a fourth aspect of the present invention is a method for manufacturing an automobile part, wherein the laser weld joint according to any one of (1) to (6) is subjected to press molding.
- a fifth aspect of the present invention is a method for manufacturing an automobile part in which a laser welded joint manufactured by the manufacturing method according to any one of (8) to (11) is subjected to press molding.
- the present invention it is possible to suppress cracks generated in the weld metal of the laser weld joint during press forming. Moreover, it is possible to suppress the occurrence of cracks in the weld metal in an automobile part obtained by press forming a laser weld joint.
- the occurrence of cracks can be suppressed by controlling the distribution density of the porosity of a predetermined size to a certain value or less.
- the occurrence of cracks can be controlled by controlling the distribution density of oxide inclusions of a predetermined size to a certain value or less.
- F By controlling the components of the weld metal so that the weld pool fluidity index of the weld metal is within a predetermined range, the fluidity of the weld pool during welding can be controlled, and porosity is a cause of cracking. The distribution density of can be reduced.
- the present invention has been completed based on the above findings.
- the laser welded joint according to the present invention includes a welded joint obtained by joining a plurality of steel plates by so-called laser-arc hybrid welding in which laser welding and arc welding are combined.
- a laser welded joint (hereinafter simply referred to as a welded joint) according to an embodiment of the present invention and a manufacturing method thereof will be described.
- “%” display of the content of each element means “mass%”.
- the welded joint according to the present embodiment is, for example, a tailored blank material, and includes a plurality of (for example, two) steel plates and a weld metal formed at a joint portion of the plurality of steel plates.
- the plurality of steel plates are butt welded using a laser.
- an automotive part is obtained by performing press molding on the welded joint according to the present embodiment.
- the thickness of each steel plate may be 0.5 mm to 4.0 mm. When used as an automobile part, it may be 0.6 mm to 2.5 mm.
- each component of the welded joint will be described in detail.
- Average hardness of weld metal 350-540 in terms of Vickers hardness
- HV Vickers hardness
- the distribution density of porosity and oxide inclusions in the weld metal is appropriately controlled, and the press molding conditions are further controlled. Even if mitigated, cracks may occur in the weld metal during press forming. Therefore, the average hardness of the weld metal is 540 or less in HV.
- the average hardness of the weld metal is less than 350 in HV, almost no cracks occur in the weld metal during press forming regardless of the porosity and the distribution density of oxide inclusions in the weld metal.
- the present invention aims to prevent the occurrence of cracks in the weld metal, the present invention is directed to weld joints having an average hardness of the weld metal of HV of 350 or more.
- the average hardness of the weld metal is limited to the range of 350 to 540 in HV.
- the average hardness of the weld metal is preferably 530 or less in HV, and more preferably 520 or less in HV.
- hydrogen-induced hydrogen cracking is more likely to occur.
- the lower limit value of the average hardness of the weld metal may be 370 or more at HV.
- the average hardness is obtained as follows. First, a welded joint is cut in a direction perpendicular to the extending direction of the weld line to produce a cross-sectional sample for hardness measurement. And the hardness of four or more places of the weld metal of a cross-sectional sample is measured with a load of 500 gf or more using a Vickers hardness tester. An average value of the measured hardness at four or more locations is calculated to obtain the average hardness. The measurement location is a position 1/4 t (t is the thickness of the weld metal in the thickness direction of the weld joint) from the surface of the weld metal.
- Porosity distribution density of diameter 2 ⁇ m or more and 50 ⁇ m or less in the weld metal 5.0 / mm 2 or less
- Porosity (void) present in the weld metal is formed when the weld metal solidifies, and accumulation of non-diffusible hydrogen Become a site.
- a porosity of about 50 ⁇ m or more that can be observed with an X-ray microscope has been controlled.
- the cause of the press crack is considered to be a fracture due to a decrease in the cross-sectional area of the weld due to the presence of porosity, that is, a decrease in the local elongation performance of the weld.
- porosity that is, a decrease in the local elongation performance of the weld.
- the porosity with a particle diameter of more than 50 ⁇ m is controlled, if the porosity with a particle diameter of 50 ⁇ m or less is large, cracks occur in the weld metal during press forming. I found it easy.
- the porosity of 2 ⁇ m to 50 ⁇ m in diameter increases the internal pressure due to accumulation of non-diffusible hydrogen in the interior, and cracks originating from the porosity occur when the weld metal undergoes plastic deformation during press forming. Presumed to be. Therefore, in order to suppress cracking of the weld metal during press forming, it is important to control the distribution density of the porosity having a diameter of 2 ⁇ m to 50 ⁇ m. Therefore, in the welded joint according to this embodiment, the distribution density of the porosity of 2 ⁇ m or more and 50 ⁇ m or less in the weld metal is 5.0 pieces / mm 2 or less, preferably 4.0 pieces / mm 2 or less, more preferably 3.
- the lower limit of the above porosity distribution density 2 ⁇ m is not particularly limited in the weld metal, since the effect is saturated as less than 0.01 pieces / mm 2, 0.01 pieces / mm 2 the lower limit It is good.
- the distribution density of porosity is determined as follows. First, the weld metal is cut in a direction perpendicular to the extending direction of the weld line, and the cut surface is mirror-polished. The mirror-polished cut surface is observed with a scanning electron microscope (SEM) at a magnification of 2000 times or more, and at least a region of 250,000 ⁇ m 2 or more per cross section is observed, and the number of porosity having a diameter of 2 ⁇ m or more and 50 ⁇ m or less is counted. The same observation is performed on two or more cross sections different from the above cross section. The porosity distribution density is obtained by dividing the number of porosity by the observation area.
- SEM scanning electron microscope
- the observation position in the cross section is not particularly specified, but the area as wide as possible should be observed for a portion that is reliably determined to be a weld metal. If the boundary between the steel plate and the weld metal part is not clear after mirror polishing, it is desirable to perform etching in advance and mark the boundary so that the weld metal part can be reliably identified.
- the diameter of a porosity is calculated
- Distribution density of oxide inclusions having a diameter of 3 ⁇ m or more in the weld metal 0.1 to 8.0 pieces / mm 2
- Oxide inclusions having a diameter of 3 ⁇ m or more function as trap sites for trapping diffusible hydrogen present in the metal lattice of the weld metal immediately after welding, so that it is possible to prevent diffusible hydrogen from flowing into the porosity. it can. This makes it possible to suppress the internal pressure due to non-diffusible hydrogen in the porosity, and to prevent cracking of the weld metal during press forming.
- the distribution density of oxide inclusions having a diameter of 3 ⁇ m or more is set to 0.1 piece / mm 2 or more.
- the distribution density of oxide inclusions having a diameter of 3 ⁇ m or more is preferably 0.2 pieces / mm 2 or more, and more preferably 0.3 pieces / mm 2 or more.
- the distribution density of oxide inclusions having a diameter of 3 ⁇ m or more in the weld metal exceeds 8.0 pieces / mm 2 , cracks originating from the oxide inclusions may occur. Therefore, in the welded joint according to the present embodiment, the distribution density of oxide inclusions having a diameter of 3 ⁇ m or more in the weld metal is 8.0 pieces / mm 2 or less, preferably 6.0 pieces / mm 2 or less, more preferably 4.0 pieces / mm 2 or less.
- the oxide inclusions are not particularly limited, but include oxides containing Al as a main component, oxides containing Si and Mn as main components, and Mg as a main component. Oxides and oxysulfides, oxides containing Ti as a main component, oxides and oxysulfides containing Ca as a main component, oxides and oxysulfides containing REM (La, Ce, etc.) as main components Furthermore, an oxide containing a plurality of the above-described elements such as (Mg, Ti, Al) oxide is included.
- the distribution density of oxide inclusions is determined as follows. First, the weld metal is cut in a direction perpendicular to the extending direction of the weld line, and the cut surface is mirror-polished. The mirror-polished cut surface is observed with a scanning electron microscope (SEM) at a magnification of 2000 times or more, and an area of at least 250,000 ⁇ m 2 per section is observed, and the number of oxide inclusions having a diameter of 3 ⁇ m or more is counted. The same observation is performed on two or more cross sections different from the above cross section. Then, the distribution density of oxide inclusions is obtained by dividing the number of oxide inclusions by the observation area.
- SEM scanning electron microscope
- the diameter of the oxide inclusions is obtained by calculating the area of the oxide inclusions and converting the area into a circle equivalent diameter.
- elemental analysis using EDS (energy dispersive X-ray spectroscopy) or WDS (wavelength dispersive X-ray spectroscopy) mounted on the SEM. And make a determination. It is preferable to use EDS or WDS for discrimination of porosity and inclusions.
- C 0.05 to 0.30% C is an element that dissolves in the weld metal during welding and affects the hardness and metal structure of the weld metal, and also the viscosity of the molten pool during laser welding. Since the weld metal is rapidly cooled after melting by laser welding, it tends to become a martensite structure, and its hardness strongly depends on the C content. If the C content is less than 0.05%, it becomes difficult to increase the hardness of the weld metal to 350 or higher in HV. As described above, the present invention is directed to a welded joint having an average hardness of the weld metal of HV of 350 or more. Therefore, the C content is 0.05% or more.
- the C content may be 0.10% or more, 0.15% or more, or 0.20% or more.
- the C content in the weld metal exceeds 0.30%, the hardness of the weld metal tends to exceed 540 in HV, and cracks are likely to occur in the weld metal during press forming. Therefore, the C content is 0.30% or less. From this point of view, the C content is preferably 0.25% or less, more preferably 0.20% or less, and more preferably 0.15% or less.
- Si 0.005 to 3.0%
- Si has an effect of controlling the phase transformation to control the structure of the metal structure of the steel sheet, and affects the formation of diffusible hydrogen and porosity in the weld metal. Therefore, Si is important for controlling the occurrence of cracks in the weld metal during press forming. If the Si content in the weld metal exceeds 3.0%, the reason is not clear, but the amount of diffusible hydrogen taken into the metal lattice during welding increases. Thereby, it becomes easy to generate
- the total content of Si is set to 3.0% or less. From this point of view, the total content of Si is preferably 2.3% or less, more preferably 2.0% or less, and even more preferably 1.7% or less.
- the Si content is less than 0.005%, the oxide in the weld metal increases, and cracking may occur during press molding. Accordingly, the Si content is 0.005% or more, more preferably 0.01% or more, and more preferably 0.05% or more.
- Al 0.005 to 1.0%
- Al similarly to Si, has the effect of controlling the phase transformation to control the structure of the metal structure of the steel sheet, and also affects the amount of diffusible hydrogen in the weld metal. Affects cracking behavior. If the Al content in the weld metal exceeds 1.0%, the reason is not clear, but the amount of diffusible hydrogen taken into the metal lattice during welding tends to increase. Thereby, it becomes easy to generate
- the Al content may be 0.005% or more. However, if the Al content is less than 0.005%, the oxide in the weld metal increases and cracking may occur during press molding. From this point of view, the Al content is preferably 0.005% or more, more preferably 0.1% or more, and more preferably 0.5% or more.
- Mn 0.5 to 6.0%
- Mn is an element contained in the steel plate and, as a result, contained in the weld metal in order to control the metal structure.
- the content of Mn is less than 0.5%, the hardenability is greatly lowered, and even if a large amount of C is contained, it is difficult to stably increase the hardness of the weld metal to 350 or higher with HV. .
- the present invention is directed to a welded joint having an average hardness of the weld metal of HV of 350 or more. Therefore, the Mn content is 0.5% or more, preferably 1.0% or more, more preferably 1.5% or more.
- the Mn content of the weld metal exceeds 6.0%, the weld metal may become brittle and cracks may occur in the weld metal. Therefore, the Mn content is 6.0% or less, preferably 4.0% or less, more preferably 2.0% or less.
- P Over 0 to 0.04% P may be used for securing the strength of the steel sheet constituting the joint. However, P is an element that embrittles the welded portion. If the P content exceeds 0.04%, cracking occurs regardless of control of the porosity distribution and the amount of diffusible hydrogen. For this reason, the upper limit is made 0.04%, preferably 0.03%. The lower limit may be over 0%, but excessive reduction leads to an increase in manufacturing costs such as refining costs, so the lower limit may be 0.0001%.
- S Over 0 to 0.01% S is an element that can increase the fluidity of the weld metal (molten metal) during welding and reduce the amount of porosity, while it is an element that embrittles the weld. If the S content exceeds 0.01%, cracking occurs regardless of the control of the distribution of porosity and the distribution density of oxide inclusions, so the upper limit is made 0.01%.
- the lower limit may be over 0%, but excessive reduction leads to an increase in manufacturing costs such as refining costs, so the lower limit may be 0.0001%.
- N More than 0 to 0.01% N is an element used for the structure control of the steel sheet constituting the joint, and has the effect of refining the grain size of the weld metal.
- the N content exceeds 0.01%, the tendency to embrittlement becomes strong due to the formation of coarse nitrides in the weld metal, so the upper limit is made 0.01%.
- the lower limit may be over 0%, but excessive reduction leads to an increase in manufacturing costs such as refining costs, so the lower limit may be 0.0001%.
- O Over 0 to 0.01% O is an element that affects the distribution of oxide inclusions in the weld metal. When the content exceeds 0.01%, the density of oxide inclusions increases, and cracks that propagate the oxide inclusions occur during press molding. For this reason, the upper limit is made 0.01%.
- Weld pool fluidity index ⁇ 0.3 to 3.0 C, Si, and S are elements that affect the fluidity of the molten pool (molten metal) during welding. Specifically, the fluidity of the molten pool improves as the content of Si and S increases. On the other hand, the lower the content of C, the better the fluidity of the molten pool.
- the molten pool fluidity index ⁇ expressed by the following equation (1) obtained in consideration of the magnitude of the influence of C, Si, and S on the fluidity of the molten pool is 0. Control the composition of the weld metal so that it becomes 3 to 3.0. Si, S, and C mean the content (% by mass) of each element in the weld metal.
- Molten pool fluidity index ⁇ Si + 200 ⁇ S ⁇ 2.7 ⁇ C (1)
- the molten pool fluidity index ⁇ is 0.3 or more, preferably 0.4 or more, and more preferably 0.8 or more.
- the molten pool fluidity index ⁇ exceeds 3.0, the porosity distribution density tends to increase. The reason for this is not clear, but the amount of gas taken into the weld metal during welding may increase. Therefore, the molten pool fluidity index ⁇ is 3.0 or less, preferably 2.5 or less, and more preferably 1.8 or less.
- the weld metal may contain one or more selected from the group consisting of Cr, Ni, Mo, Cu, Nb, Ti, V, Ca, REM, and B shown below.
- Ni and Mo are elements contained in the steel plate to control the metal structure, and as a result, contained in the weld metal.
- the lower limit of Cr, Ni, and Mo is 0%, but it is preferable to set 0.0001% as the lower limit to ensure the effect of addition.
- the Cr content of the weld metal exceeds 5.0%, the Ni content exceeds 10.0%, and the Mo content exceeds 1.0%, the weld metal becomes brittle and cracks occur in the weld metal. There is a case. Therefore, the Cr content is 5.0% or less, the Ni content is 10.0% or less, and the Mo content is 1.0% or less.
- Ms ⁇ 250 Even if the content of Cr, Ni, and Mo is within the above range, if the Ms point of the weld metal represented by the following formula (2) is less than 250 ° C., cracks occur in the weld metal during press forming. There is. Although this cause is not certain, the structure of the metal structure of the weld metal may have an influence. That is, when the Ms point is less than 250 ° C., the ratio of the martensite of the bct structure among the martensites in the weld metal increases. Thereby, a crack may occur easily in the weld metal.
- each element when one or more selected from the group of Cr, Ni and Mo is contained in the weld metal, the inclusion of each element so that the value of Ms represented by the following formula (2) is 250 or more.
- the amount is preferably determined, and the content of each element is more preferably determined so as to be 280 or more.
- Ms 561-474 ⁇ C-33 ⁇ Mn-17 ⁇ Ni-17 ⁇ Cr-21 ⁇ Mo (2) where, in the formula (2), each element symbol represents each element included in the weld metal. Indicates the content (% by mass), and is zero when not contained.
- Cu 0 to 1.0%
- Cu is an element contained in the welded metal as a result of being contained in the steel plate to control the structure of the metal structure as will be described later.
- the Cu content is preferably 1.0% or less.
- the lower limit value of Cu is 0%, but 0.0001% is preferably set as the lower limit value in order to ensure the effect of addition.
- Nb, Ti and V 0 to 0.2% in total Nb, Ti, and V have the effect of improving the strength of the steel sheet as precipitation strengthening elements, and are used to refine crystal grains in the weld metal after laser welding and crystal grains in the weld heat affected zone.
- the total content of Nb, Ti and V exceeds 0.2%, an oxide is formed in the weld metal, and the oxide may become a starting point of cracking during press molding. Therefore, the total content of Nb, Ti and V is preferably 0.2% or less.
- the lower limit value of the total content of Nb, Ti and V is 0%, but 0.0001% is preferably set as the lower limit value in order to ensure the effect of addition.
- Ca and REM 0 to 0.01% in total Ca and REM have an effect of controlling inclusions that can be a starting point of cracks in the raw steel plate and weld metal of the weld joint.
- the total content of Ca and REM exceeds 0.01%, an oxide is formed in the weld metal, and the oxide may become a starting point of cracking during press molding. Therefore, the total content of Ca and REM is preferably 0.01% or less.
- the lower limit of the total content of Ca and REM is 0%, but 0.0001% is preferably set as the lower limit in order to reliably obtain the effect of addition.
- REM is a generic name for a total of 17 elements of Sc, Y, and lanthanoid, and the content of REM means the total content of one or more elements of REM.
- the “lanthanoid” is a general term for a total of 15 elements from La to Lu.
- B 0 to 0.01% B has the effect of improving the strength and toughness of the weld metal.
- the B content is preferably 0.01% or less.
- the lower limit value of B is 0%, but 0.0001% is preferably set as the lower limit value in order to ensure the effect of addition.
- the weld metal of the welded joint according to the present embodiment contains, for example, the above elements, and the remaining part is made of Fe and impurities.
- “Impurity” means a component that is mixed due to raw materials such as ore and scrap and other factors when industrially producing steel materials.
- an element of the plating material is included in the weld metal as an impurity.
- Fe is a main component of the weld metal. If the Fe content in the weld metal is less than 90%, it becomes difficult to set the Ms point of the weld metal calculated by the above-described equation (2) to 250 ° C. or higher. Therefore, the Fe content is preferably 90% or more.
- the chemical composition of the weld metal is determined as follows. First, from the weld joint, only the weld metal is cut and the sample is cut out, or the welded portion is exposed by polishing. This sample is quantitatively analyzed according to the standards described in Table 1 of JIS G0321 (2010). Thereby, the chemical composition of a weld metal can be calculated
- Average composition of a plurality of steel plates The chemical composition of a weld metal depends on the average composition and welding conditions of a plurality of steel plates (base materials) joined together via the weld metal. Therefore, the average composition of the plurality of steel plates is preferably in the range of the chemical composition of the weld metal described above. In addition, even if the average composition of a some steel plate is not the range of the chemical composition of the above-mentioned weld metal by using a welding wire or insert metal at the time of welding, it is possible to adjust the chemical composition of a weld metal. The amount of oxygen can be set to a desired range by adjusting the welding conditions.
- the average composition of a plurality of steel sheets is determined by calculating the average content of each element by the following formula.
- X ave represents the average content of an arbitrary element X
- tk represents the thickness of the kth steel plate among the n steel plates
- Xk represents the kth
- the content of element X contained in the steel sheet is shown.
- the average content X ave of the element X of the two steel plates A and B can be obtained by the following equation (4). And average content can be calculated about each element and the average composition of two steel plates can be calculated
- X ave (t A ⁇ X A + t B ⁇ X B ) / (t A + t B ) (4)
- composition analysis of each steel plate sample preparation and quantitative analysis are performed in accordance with the standards described in Table 1 of JIS G0321 (2010). In this way, composition analysis of the steel sheet can be performed.
- the surface of the steel plate having the above-described configuration may be plated.
- the amount of diffusible hydrogen in the weld metal can be reduced. The reason for this is presumed to be that the plating component evaporated by the welding heat shields the molten metal portion in a gaseous state, and as a result, suppresses the penetration of moisture existing in the space around the molten metal into the molten metal. Therefore, at least one of the plurality of steel plates constituting the welded joint is preferably a plated steel plate, and more preferably all are plated steel plates.
- the type of plating is not particularly limited, and various types of plating such as hot dipping, alloying hot dipping, and electroplating can be used. Further, the thickness of the plating is not particularly limited.
- the plating material for example, Zn, Ni, Al, Fe, and Sn can be used.
- alloy plating may be used. Specifically, alloy plating having a composition such as Zn—Sn, Zn—Al—Mg, or Zn—Al—Mg—Si may be used.
- an element of the plating material may be included as an impurity in the chemical composition of the weld metal.
- Amount of diffusible hydrogen in weld metal (mass ppm): “3.570-0.0066 ⁇ HV WM ” or less
- weld metal cracking during the press working of welded joints is caused by accumulation of non-diffusible hydrogen. It is thought that the crack originated from the porosity with increased internal pressure. Therefore, if non-diffusible hydrogen in the porosity can be defined, weld metal cracking during the press working of the welded joint should be suppressed. However, measuring non-diffusible hydrogen in porosity is unrealistic. The present inventors have found that non-diffusible hydrogen in the porosity is correlated with the diffusible hydrogen in the metal lattice with a slight time difference.
- diffusible hydrogen remains excessively in the metal lattice due to dissociation of H 2 O in the atmosphere during welding. Thereafter, these diffusible hydrogens are (1) discharged from the steel plate surface, (2) accumulated in the porosity, or (3) oxide-based inclusions, as shown in FIG. 2B showing the initial stage of diffusion. Trapped in Thereafter, as shown in FIG. 2C showing the late stage of diffusion, non-diffusible hydrogen accumulated inside the porosity is also discharged out of the metal lattice with the passage of time.
- the amount of non-diffusible hydrogen in the porosity correlates with the amount of diffusible hydrogen in the metal lattice.
- the specified holding time t is 7000 ⁇ C-400 (the time required to enter the latter stage of diffusion shown in FIG. 2C and decrease the amount of diffusible hydrogen and further decrease the amount of hydrogen inside the porosity accompanying the decrease. min) or more.
- hydrogen in the weld metal is roughly classified into diffusible hydrogen and non-diffusible hydrogen.
- the amount of diffusible hydrogen in the weld metal can be calculated using a temperature programmed desorption method. Specifically, for example, when the weld metal is heated from room temperature to 200 ° C. at 100 ° C./h, the amount of hydrogen released from the weld metal is measured by a gas chromatograph, and the amount of diffusible hydrogen is calculated from the measured amount of hydrogen. it can.
- Main metal structure of weld metal martensite of bcc (body centered cubic) structure
- the metal structure of weld metal is a factor affecting the cracking behavior during press forming. The cause is not clear, but as a result of the investigation by the present inventors, if the main metal structure of the weld metal is martensite having a bct (body center square) structure, cracks are likely to occur in the weld metal during press forming. I understood. Therefore, the main metal structure of the weld metal is preferably martensite having a bcc structure.
- the martensite having the bcc structure may be martensite in which no carbide is present or tempered martensite in which iron carbide is precipitated.
- the remaining structure may be one or two of bainite and retained austenite.
- the main metal structure refers to a metal structure having an area ratio of 80% or more.
- the metal structure of the weld metal preferably has a martensite having a bcc (body centered cubic) structure in an area ratio of 90% or more.
- a metal structure can be specified by observing with SEM or a transmission electron microscope (TEM), for example.
- TEM transmission electron microscope
- the crystal structure of martensite can be specified by, for example, an X-ray diffraction method.
- the lattice constants of the a-axis and c-axis of the ⁇ 100 ⁇ plane are measured by the X-ray diffraction method, and the cubic (bcc) or tetragonal (bct) is determined from the axial ratio c / a.
- the c / a value is 1.007 or less, the martensite structure is assumed to be a bcc structure.
- Manufacturing conditions for welded joints The inventors have conducted various studies on preferable conditions for manufacturing a welded joint having the above-described configuration. Specifically, research was conducted on methods for controlling the amount of diffusible hydrogen and the amount of porosity in the weld metal. As a result, it was found that the amount of diffusible hydrogen and porosity in the weld metal can be controlled by appropriately setting the absolute humidity of the welding atmosphere, the welding speed, and the heat treatment conditions of the welded joint before forming. Hereinafter, the manufacturing conditions of the welded joint will be described in detail.
- Absolute humidity of welding atmosphere 5 g / m 3 to 25 g / m 3
- Absolute humidity during laser welding affects the amount of diffusible hydrogen in the weld metal. Specifically, when the absolute humidity exceeds 25 g / m 3 , the amount of diffusible hydrogen in the weld metal becomes excessive, and delayed fracture may occur in the weld metal before press forming. On the other hand, if the absolute humidity exceeds 25 g / m 3 , the amount of diffusible hydrogen remaining in the weld metal cannot be sufficiently reduced even if heat treatment is performed for a predetermined time before press forming. For this reason, even when delayed fracture does not occur before press molding, cracks are likely to occur during press molding.
- the absolute humidity during laser welding is 25 g / m 3 or less, preferably 20 g / m 3 or less.
- the absolute humidity is less than 5 g / m 2 , the distribution density of oxide inclusions having an effect of preventing hydrogen accumulation in the porosity by trapping hydrogen is reduced. This is because the moisture reduction, the amount of O atoms resulting from the dissociation reaction of the place H 2 O in the weld (H 2 O ⁇ 2H + O ) is reduced, so that the amount of O to oxidation reaction with the molten metal is reduced It is thought that it was because. Therefore, the absolute humidity is at 5 g / m 2 or more, and more preferably preferably at 7 g / m 2 or more and 10 g / m 2 or more.
- Welding speed 8 m / min or less
- the laser welding speed is a factor that affects the amount of diffusible hydrogen and porosity of the weld metal.
- the laser welding speed exceeds 8 m / min, the amount of diffusible hydrogen and / or porosity of the weld metal increases, and cracks are likely to occur in the weld metal.
- the laser welding speed is 8 m / min or less, preferably 6 m / min or less, and more preferably 5 m / min or less.
- Holding temperature of welded joint after welding and before press forming 10-100 ° C
- the weld joint is held at a predetermined temperature. If the holding temperature is less than 10 ° C, the amount of diffusible hydrogen cannot be reduced sufficiently. If the holding temperature exceeds 100 ° C, the mechanical properties of the steel sheet other than the weld metal change. For this reason, it is preferable that the welded joint after laser welding and before press molding is held in a temperature range of 10 to 100 ° C.
- the holding temperature is preferably 20 ° C. or higher, and preferably 80 ° C. or lower.
- Holding time (min) of welded joint after completion of welding and before press forming “7000 ⁇ C-400” or more Holding time (min) of the welded joint in a temperature range of 10 to 100 ° C. after completion of laser welding and before press forming ) Affects the amount of diffusible hydrogen in the weld metal.
- the holding time t is set so as to satisfy the following expression (6), and more preferably, the holding time t is set so as to satisfy the following expression (7).
- the holding time t may be set to a lower limit of 60 minutes, preferably 100 minutes, more preferably 180 minutes, in addition to the lower limit value set by the above formula (6) or (7).
- the conditions other than the above welding conditions are not particularly limited. However, it is known that various conditions such as a gap between steel plates during welding, a laser defocus amount, and a laser pulse width affect the porosity formation. Therefore, the above various conditions are appropriately set according to the type and output of the laser used.
- the type of laser oscillator is not particularly limited. For example, an oscillator such as a fiber laser, a YAG laser, a disk laser, a semiconductor laser, or a carbon dioxide laser (CO 2 laser) can be used.
- a plurality of steel plates may be joined by so-called laser-arc hybrid welding using a welding wire. Also, the combination of plate thicknesses is not particularly limited.
- the difference in thickness of the steel plates to be welded exceeds 2 mm, distortion tends to concentrate on the weld metal, and cracks are likely to occur. Therefore, it is preferable that the difference in thickness of the steel plates to be welded is 2 mm or less.
- the steel plate F is a plated steel plate (GA) obtained by subjecting a cold-rolled steel plate to alloy hot-dip galvanizing
- the steel plate J is a plated steel plate (GI) obtained by subjecting the cold-rolled steel plate to hot dip galvanization
- the other steel plates are Cold rolled steel sheet (CR).
- HV WM (HV) average hardness of weld metal
- l porosity distribution density (pieces / mm 2 )” — distribution density of porosity of 2 ⁇ m to 50 ⁇ m in the weld metal
- M inclusion distribution density (pieces / mm 2 )” — distribution density of oxide inclusions having a diameter of 3 ⁇ m or more in the weld metal
- n C H (mass ppm)” — weld metal Diffusible hydrogen content CH
- O Light-side value of formula (5)”: 3.57 ⁇ 0.0066 ⁇ HV WM value
- p “Crystal structure of martensite” —Crystal structure of martensite in weld metal ( q
- the main metal structure was martensite.
- Tables 6 and 7 for welded joints whose martensite crystal structure is shown as bcc, the main metal structure of the weld metal was a martensite structure of bcc structure, and welds shown as bct.
- the joint means that the main metal structure of the weld metal was a martensitic structure having a bct structure.
- the crystal structure of martensite was specified by the X-ray diffraction method.
- the lattice constants of the a-axis and c-axis of the ⁇ 100 ⁇ plane were measured by the X-ray diffraction method, and the cubic (bcc) or tetragonal (bct) was determined from the axial ratio c / a.
- the c / a value was 1.007 or less
- the martensite structure was regarded as the bcc structure.
- the chemical composition of the weld metal was determined by the method described in “5. How to determine the chemical composition of the weld metal” described above.
- the average hardness (HV) of the weld metal was determined as follows. First, the weld joint was cut in a direction perpendicular to the extending direction of the weld line to produce a cross-sectional sample for hardness measurement. And the hardness of four places of the weld metal of a cross-sectional sample was measured with the load of 500 gf or more using the Vickers hardness tester. The average value of the measured hardness at four locations was calculated to obtain the average hardness. The measurement location was a position of 1/4 t from the surface of the weld metal (t is the thickness of the weld metal in the thickness direction of the welded joint).
- the distribution density of porosity with a diameter of 2 ⁇ m to 50 ⁇ m in the weld metal was determined as follows. First, the weld joint is cut in a direction perpendicular to the extending direction of the weld line, and the cut surface is mirror-polished. The portion corresponding to the weld metal in the mirror-polished cut surface was observed by SEM, and the number of porosity having a diameter of 2 ⁇ m to 50 ⁇ m was counted. Then, the distribution density of porosity was obtained by dividing the number of porosity by the observation area. In addition, SEM observation was performed about three or more different cross sections so that an observation area might be 5 mm ⁇ 2 > or more. In addition, since porosity has various shapes, it evaluated as a circle equivalent diameter of the same area.
- the distribution density of oxide inclusions with a diameter of 3 ⁇ m or more in the weld metal was determined by observing the mirror-polished cut surface with SEM using the same sample as the porosity observation described above, and an oxide type with an equivalent circle diameter of 3 ⁇ m or more. The number of inclusions was counted. SEM observation was performed on three or more different cross sections so that the observation area was 5 mm 2 or more. For those in which the porosity and inclusion cannot be distinguished from the SEM image alone, oxygen and other elements are analyzed using the EDS mounted on the SEM. It was judged.
- the amount of diffusible hydrogen contained in the weld metal was measured as follows. First, a sample containing a weld metal was cut out from each welded joint for measuring the amount of diffusible hydrogen. The sample cut out was heated at a temperature increase rate of 100 ° C./h. Then, the hydrogen released from the sample during heating to 200 ° C. from room was measured by gas chromatography, Table 6, was the amount of diffusible hydrogen C H shown in Table 7. In addition, since the hydrogen contained in the steel plate before welding is a negligible amount, in this example, it was assumed that the steel plate does not contain hydrogen and only the weld metal contains hydrogen.
- the diffusible hydrogen content of the weld metal was calculated from the mass of the weld metal and the hydrogen content measured as described above.
- the mass of the weld metal was calculated by the following formula (8).
- Aw is the mass of the weld metal
- At is the mass of the sample
- Ww is the width of the weld metal
- Wt is the width of the sample (with respect to the extending direction of the weld line). Vertical length).
- Aw At ⁇ Ww / Wt (8)
- the width Ww of the weld metal was obtained as follows. First, the sample is cut in a direction perpendicular to the extending direction of the weld line, and 1 / 8t (t is the thickness of the weld metal), 1 / 4t, 1 / 2t, 3 / 4t and 7 from the surface of the weld metal. The width at the position of / 8t was measured. And the average value of the measured width of five places was computed, and it was set as the width Ww of a weld metal.
- the metal structure of the weld metal was observed by SEM. Specifically, a sample containing a weld metal was cut out from each weld joint for observation of the metal structure. And the cut surface of the weld metal of the cut-out sample was observed by SEM. The crystal structure of martensite in the weld metal was identified by the X-ray diffraction method.
- the draw bend test will be described.
- lubricating oil was applied to both surfaces of the weld joints 1 to 57 described above.
- the diameter d of the punch 101 of the press test apparatus 100 is set to 100 mm
- a punch shoulder radius r p is a 10 mm
- die shoulder radius r d is a 5 mm
- a clearance c between the punch 101 and the die 102 Was 3 mm.
- the blank holding force (BHF) at the time of press forming by the blank holder 103 is the tensile strength applied to the vertical wall of the welded joint during press forming is 0. 0 of the lower tensile strength of the two joined steel plates. Adjusted to 5 times.
- the molding height was set to 60 mm.
- the weld joint was installed in the press test apparatus so that the weld line passed through the approximate center of the upper surface of the punch.
- the porosity distribution density increased due to the small molten pool fluidity index ⁇ . For this reason, it is presumed that the influence of the internal pressure due to the non-diffusible hydrogen in the porosity was greatly influenced. However, in the welded joint 1, since the average hardness of the weld metal was small, no crack was confirmed in the weld metal.
- the amount of porosity cannot be suppressed because the welding speed was high, and the porosity is the starting point in the draw bend test due to the influence of internal pressure due to non-diffusible hydrogen in the porosity. It is estimated that cracking occurred.
- the porosity distribution density increased due to the small molten pool fluidity index ⁇ . For this reason, the internal pressure due to non-diffusible hydrogen in the porosity cannot be sufficiently reduced, and it is presumed that cracks originating from the porosity occurred in the draw bend test.
- the distribution density of the oxide inclusions could not be sufficiently increased because the absolute humidity during welding was low.
- the value of the C H indicating the amount of hydrogen between the metal grid was possible to reduce to a suitable value, due to which could not be obtained a sufficient effect of trapping diffusible hydrogen by oxide inclusions
- the internal pressure due to non-diffusible hydrogen in the porosity cannot be sufficiently reduced, and it is presumed that cracks originating from the porosity occurred in the draw bend test.
- the distribution density of oxide inclusions could not be sufficiently increased due to the low absolute humidity during welding.
- the value of the C H indicating the amount of hydrogen between the metal grid was possible to reduce to a suitable value, due to which could not be obtained a sufficient effect of trapping diffusible hydrogen by oxide inclusions
- the internal pressure due to non-diffusible hydrogen in the porosity cannot be sufficiently reduced, and it is presumed that cracks originating from the porosity occurred in the draw bend test.
- the average hardness of the weld metal deviates from the preferred range due to the excessive C content in the molten metal part, and cracks occurred in the weld metal. It is estimated that occurred.
- the porosity distribution density increased due to the small weld pool fluidity index ⁇ . For this reason, it is estimated that the crack which originated in the porosity by the draw bend test generate
- the occurrence of cracks in the weld metal can be prevented even when a laser welded joint including a high-strength steel plate is press-formed.
- a laser welded joint including a high-strength steel plate is press-formed.
- the laser welded joint according to the present invention can be used not only as a skeleton part of a vehicle body but also as a panel part and an underbody part.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Plasma & Fusion (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Laser Beam Processing (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
本願は、2014年11月19日に、日本に出願された特願2014-234957号に基づき優先権を主張し、その内容をここに援用する。
(1)本発明の第一の態様は、複数の鋼板の間に設けられた溶接金属を有するレーザー溶接継手であって、前記溶接金属の化学組成が、質量%で、C: 0.05~0.30%、Si:0.005~3.0%、Al:0.005~1.0%、Mn:0.5~6.0%、P:0超~0.04%、S:0超~0.01%、N:0超~0.01%、O:0超~0.01%、Cu:0~1.0%、Nb+Ti+V:0~0.2%、Ca+REM:0~0.01%、B:0~0.01%、Cr:0~5.0%、Ni:0~10.0%、Mo:0~1.0%、及び、残部:Feおよび不純物を含むとともに、0.3≦Si+200×S-2.7×C≦3.0を満たし、前記溶接金属の平均硬さがビッカース硬さで350~540であり、前記溶接金属では、直径2μm~50μmのポロシティの分布密度が5.0個/mm2以下であり、前記溶接金属では、直径3μm以上の酸化物系介在物の分布密度が0.1~8.0個/mm2である。
(2)上記(1)に記載のレーザー溶接継手では、前記溶接金属の化学組成が、質量%で、Cu:0.0001~1.0%、Nb+Ti+V:0.0001~0.2%、Ca+REM:0.0001~0.01%、B:0.0001~0.01%、Cr:0.0001~5.0%、Ni:0.0001~10.0%、及びMo:0.0001~1.0%、の群から選択される少なくとも一種を含んでもよい。
(3)上記(1)又は(2)に記載のレーザー溶接継手では、前記溶接金属中の拡散性水素量CHが、単位mass ppmとして、下記の(a)式を満足してもよい。
CH≦3.570-0.0066×HVWM (a)式
ただし、(a)式においてHVWMは、前記溶接金属のビッカース硬さでの平均硬さを示す。
(4)上記(1)~(3)のいずれか一項に記載のレーザー溶接継手では、前記溶接金属の金属組織の80%以上がマルテンサイトであり、そのマルテンサイトの構造がbcc構造であってもよい。
(5)上記(1)~(4)のいずれか一項に記載のレーザー溶接継手では、下記の(b)式によって表されるMsの値が250以上であってもよい。
Ms=561-474×C-33×Mn-17×Ni-17×Cr-21×Mo (b)式
(6)上記(1)~(5)のいずれか一項に記載のレーザー溶接継手では、前記複数の鋼板のうちの少なくとも1つがめっき鋼板であってもよい。
を満たす。
t≧7000×C-400 (c)式
ただし、(c)式においてtは単位を分とする時間を示す。
(9)上記(8)に記載のレーザー溶接継手の製造方法では、前記溶接金属の化学組成が、質量%で、Cu:0.0001~1.0%、Nb+Ti+V:0.0001~0.2%、Ca+REM:0.0001~0.01%、B:0.0001~0.01%、Cr:0.0001~5.0%、Ni:0.0001~10.0%、及びMo:0.0001~1.0%、の群から選択される少なくとも一種を含んでもよい。
(10)上記(8)又は(9)に記載のレーザー溶接継手の製造方法では、下記の(d)式によって表されるMsの値が250以上であってもよい。
Ms=561-474×C-33×Mn-17×Ni-17×Cr-21×Mo (d)式
(11)上記(8)~(10)のいずれか一項に記載のレーザー溶接継手の製造方法では、前記複数の鋼板のうちの少なくとも1つがめっき鋼板であってもよい。
(A)溶接金属の硬さが大きいほど割れが発生しやすい。
(B)溶接金属中の拡散性水素量が高いほどポロシティ中の非拡散性水素量が高く、そのポロシティ内の水素による内圧の影響によりプレス成形時に溶接金属での割れが発生しやすい。
(C)溶接金属の硬さに応じて、割れが発生しうる限界拡散性水素量が変化する。
(D)図1に示すようなポロシティ(空隙)が脆性破壊の起点となる場合があるため、所定の大きさのポロシティの分布密度を一定値以下に制御することによって、割れの発生を抑制できる。
(E)所定の大きさの酸化物系介在物の分布密度を一定値以下に制御することによって、割れの発生を制御できる。
(F)溶接金属の溶融池流動性指標が所定の範囲になるように溶接金属の成分を制御することで溶接時の溶融池の流動性を制御することができ、割れの発生因子であるポロシティの分布密度を低減することができる。
尚、各鋼板の板厚は、0.5mm~4.0mmであればよい。自動車部品として用いられる場合には、0.6mm~2.5mmであればよい。以下、溶接継手の各構成要素について詳細に説明する。
溶接金属の平均硬さがビッカース硬さ(以下、HVとも記載する。)で540を超えると、溶接金属中のポロシティや酸化物系介在物の分布密度を適切に制御し、さらにプレス成形条件を緩和しても、プレス成形時に溶接金属において割れが発生する場合がある。したがって、溶接金属の平均硬さは、HVで540以下とする。
一方、溶接金属の平均硬さがHVで350未満の場合、溶接金属中のポロシティや酸化物系介在物の分布密度にかかわらず、プレス成形時に溶接金属において割れはほとんど発生しない。上述したように、本発明は溶接金属における割れの発生の防止を目的とするので、本発明は、溶接金属の平均硬さがHVで350以上の溶接継手を対象とする。このため、溶接金属の平均硬さはHVで350~540の範囲に制限される。溶接金属の平均硬さは、HVで530以下であることが好ましく、HVで520以下であることが更に好ましい。
また、溶接金属の平均硬さがHVで370以上の場合に水素起因の水素割れがより発生しやすくなる。HVで370以上の場合の水素起因の水素割れを防止することを課題とする場合には、溶接金属の平均硬さの下限値をHVで370以上としてもよい。
まず、溶接線の延伸方向に対して垂直な方向に溶接継手を切断し、硬さ測定用の断面試料を作製する。そして、断面試料の溶接金属の4箇所以上の硬さを、ビッカース硬さ試験機を用いて500gf以上の荷重で測定する。測定した4箇所以上の硬さの平均値を算出して、平均硬さとする。測定箇所は、溶接金属の表面から1/4t(tは、溶接継手の板厚方向における溶接金属の厚み)の位置とする。
溶接金属中に存在するポロシティ(空隙)は、溶接金属が凝固する際に形成され、非拡散性水素の集積サイトとなる。
従来は、非特許文献3に記載されているように、プレス割れ防止のためのポロシティ制御では、X線顕微鏡で観察可能な50μm程度以上のポロシティの制御が行われてきた。これは、従来、プレス割れの原因は、ポロシティが存在することによる溶接部断面積の減少、すなわち溶接部の局部延性能の低下による破断であると考えられていたためである。しかしながら、本発明者らが鋭意検討した結果、直径50μm超の粒径のポロシティを制御しても、直径50μm以下の粒径のポロシティが多い場合には、プレス成形時に溶接金属において割れが発生しやすいことが分かった。これは、直径2μm~50μmのポロシティは、その内部に非拡散性水素が集積することにより内圧が高まり、プレス成形時に溶接金属が塑性変形する際に該ポロシティを起点とする割れが発生するためであると推定される。
従って、プレス成形時の溶接金属の割れを抑制するためには、直径2μm以上50μm以下のポロシティの分布密度を制御することが重要である。
そこで、本実施形態に係る溶接継手では、溶接金属中における2μm以上50μm以下のポロシティの分布密度を5.0個/mm2以下、好ましくは4.0個/mm2以下、更に好ましくは3.0個/mm2以下に制御することで、プレス成形時の割れの発生を抑制する。
溶接金属中における2μm以上のポロシティの分布密度の下限値は特に限定されるものではないが、0.01個/mm2未満としても効果は飽和するため、0.01個/mm2を下限値としてもよい。
まず、溶接線の延伸方向に対して垂直な方向に溶接金属を切断し、切断面を鏡面研磨する。鏡面研磨した切断面を、走査型電子顕微鏡(SEM)によって2000倍以上の倍率で、1断面について少なくとも250000μm2以上の領域を観察し、直径が2μm以上50μm以下のポロシティの個数を数える。同様の観察を、上記断面と異なる、2つ以上の断面について行う。そして、ポロシティの個数を観察面積で除することによって、ポロシティの分布密度とする。断面内の観察位置は特に指定しないが、確実に溶接金属と判断される箇所について、できる限り広い領域を観察するものとする。なお、鏡面研磨後に鋼板と溶接金属部の境界が明確ではない場合は、事前にエッチングを行い、境界をマーキングしておき、溶接金属部を確実に判別できる状態にしておくことが望ましい。
なお、ポロシティの直径は、ポロシティの面積を求め、その面積を円相当径に換算することによって求める。
直径3μm以上の酸化物介在物は、溶接直後の溶接金属の金属格子中に存在する拡散性水素をトラップするトラップサイトとして機能するため、拡散性水素がポロシティ内に流入することを抑制することができる。これにより、ポロシティ内の非拡散性水素による内圧を抑制することが可能となり、プレス成形時の溶接金属の割れを防止することが可能となる。この効果を得るために、本実施形態に係る溶接継手では、直径3μm以上の酸化物系介在物の分布密度を0.1個/mm2以上とする。直径3μm以上の酸化物系介在物の分布密度は、0.2個/mm2以上であることが好ましく、0.3個/mm2以上であることが更に好ましい。
一方、溶接金属における直径3μm以上の酸化物系介在物の分布密度が8.0個/mm2を超える場合、酸化物系介在物が起点となる割れが発生する虞がある。従って、本実施形態に係る溶接継手では、溶接金属における直径3μm以上の酸化物系介在物の分布密度を8.0個/mm2以下、好ましくは6.0個/mm2以下、更に好ましくは4.0個/mm2以下とする。
尚、酸化物系介在物は、特に限定するものではないが、アルミナに代表されるAlを主成分として含有する酸化物、SiやMnを主成分とする酸化物、Mgを主成分として含有する酸化物および酸硫化物、Tiを主成分として含有する酸化物、Caを主成分として含有する酸化物および酸硫化物、REM(La、Ceなど)を主成分として含有する酸化物および酸硫化物、さらには、(Mg,Ti,Al)酸化物のように、前述の元素を複数含むような酸化物などを含む。
まず、溶接線の延伸方向に対して垂直な方向に溶接金属を切断し、切断面を鏡面研磨する。鏡面研磨した切断面を、走査型電子顕微鏡(SEM)によって2000倍以上の倍率で、1断面について少なくとも250000μm2以上の領域を観察し、直径が3μm以上の酸化物系介在物の個数を数える。同様の観察を、上記断面と異なる、2つ以上の断面について行う。そして、酸化物系介在物の個数を観察面積で除することによって、酸化物系介在物の分布密度とする。
なお、酸化物系介在物の直径は、酸化物系介在物の面積を求め、その面積を円相当径に換算することによって求める。
なお、溶接金属中には、酸化物系介在物以外の介在物が存在するので、SEMに搭載したEDS(エネルギー分散型X線分光)あるいはWDS(波長分散型X線分光)を用いた元素分析を行い、その判別を行う。ポロシティと介在物の判別にもEDSあるいはWDSを用いることが好ましい。
以下、本実施形態に係る溶接継手の溶接金属の化学組成と、その限定理由を説明する。
Cは、溶接中に溶接金属に固溶し、溶接金属の硬さおよび金属組織、更にはレーザー溶接時の溶融池の粘性に影響を及ぼす元素である。溶接金属は、レーザー溶接による溶融後に急冷されるため、マルテンサイト組織になりやすく、その硬さはC含有量に強く依存する。C含有量が0.05%未満であると、溶接金属の硬さをHVで350以上にすることが困難になる。上述したように本発明は、溶接金属の平均硬さがHVで350以上の溶接継手を対象としている。したがって、C含有量は0.05%以上とする。このような観点から、C含有量は、0.10%以上、0.15%以上、又は、0.20%以上としてもよい。
一方、溶接金属中のC含有量が0.30%を超えると、溶接金属の硬さがHVで540を超えやすくなり、プレス成形時に溶接金属において割れが発生しやすくなる。したがって、C含有量は0.30%以下とする。このような観点からみた場合、C含有量は、0.25%以下であることが好ましく、0.20%以下であることがより好ましく、0.15%以下であることがより好ましい。
Siは、相変態を制御して鋼板の金属組織の構成を制御する効果を有すると共に、溶接金属中の拡散性水素量およびポロシティの形成に影響を及ぼす。従って、Siは、プレス成形時の溶接金属における割れの発生を制御するために重要である。溶接金属中のSiの含有量が3.0%を超えると、理由は定かではないが、溶接中に金属格子中に取り込まれる拡散性水素量が高くなる。これにより、プレス成形時に溶接金属において割れが発生しやすくなる。さらにSi量が高いほど、溶接時の溶融部の流動性が増加し、微小なポロシティ量が減少する。ただし、理由は定かではないが、3.0%を超えると逆にポロシティ量が増加する傾向に転じる。このため、Siの合計含有量は、3.0%以下とする。このような観点からみた場合、Siの合計含有量は、2.3%以下であることが好ましく、2.0%以下であることがより好ましく、1.7%以下であることがより好ましい。
一方、Siの含有量が0.005%未満であると、溶接金属中の酸化物が増加し、プレス成形時に割れが発生する可能性がある。従って、Siの含有量は、0.005%以上であり、0.01%以上であることがより好ましく、0.05%以上であることがより好ましい。
Alも、Siと同様に、相変態を制御して鋼板の金属組織の構成を制御する効果を有すると共に、溶接金属中の拡散性水素量に影響を及ぼすことで、プレス成形時の溶接金属における割れの発生挙動に影響を及ぼす。溶接金属中のAlの含有量が1.0%を超えると、理由は定かではないが、溶接中に金属格子中に取り込まれる拡散性水素量が高くなる傾向にある。これにより、プレス成形時に溶接金属において割れが発生しやすくなる。このため、Alの含有量は、1.0%以下とする。このような観点からみた場合、Alの含有量は、0.8%以下であることが好ましく、0.6%以下であることがより好ましく、0.4%以下であることがより好ましい。
一方、Alの含有量は0.005%以上であればよい。しかしながら、Alの含有量が0.005%未満であると、溶接金属中の酸化物が増加し、プレス成形時に割れが発生する可能性がある。このような観点からみた場合、Alの含有量は、0.005%以上とすることが好ましく、0.1%以上であることがより好ましく、0.5%以上であることがより好ましい。
Mnは、金属組織を制御するために鋼板に含有され、その結果、溶接金属に含有される元素である。Mnの含有量が0.5%未満であると、焼き入れ性が大きく低下して、Cを多量に含んでいても溶接金属の硬さを安定的にHVで350以上にすることが難しくなる。本発明は、溶接金属の平均硬さがHVで350以上の溶接継手を対象としている。したがって、Mn含有量は0.5%以上、好ましくは1.0%以上、より好ましくは1.5%以上とする。
一方、溶接金属のMn含有量が6.0%を超えると、溶接金属が脆化して溶接金属において割れが発生する場合がある。したがって、Mn含有量は6.0%以下、好ましくは4.0%以下、より好ましくは2.0%以下とする。
Pは、継ぎ手を構成する鋼板の強度確保のために用いられることがある。しかしながら、Pは溶接部を脆化させる元素であり、Pの含有量が0.04%を超えると、ポロシティの分布や拡散性水素量を制御にかかわらず、割れを生じさせる。このため、その上限を0.04%、好ましくは0.03%とする。
下限は0%超であればよいが、過度の低減は、精錬コスト等の製造コスト増につながるので、下限を0.0001%としてもよい。
Sは、溶接時の溶接金属(溶融金属)の流動性を高め、ポロシティ量を減らすことができる元素であるが、一方で、溶接部を脆化させる元素である。Sの含有量が0.01%を超えると、ポロシティの分布や酸化物系介在物の分布密度の制御にかかわらず、割れを生じさせるため、その上限を0.01%とする。
下限は0%超であればよいが、過度の低減は、精錬コスト等の製造コスト増につながるので、下限を0.0001%としてもよい。
Nは、継ぎ手を構成する鋼板の組織制御に用いられる元素であり、溶接金属の粒径微細化の効果を有する。しかしながら、N量が0.01%を超えると、溶接金属内の粗大窒化物の形成等により、脆化傾向が強くなるため、その上限を0.01%とする。下限は、0%超であればよいが、過度の低減は、精錬コスト等の製造コスト増につながるので、下限を0.0001%としてもよい。
Oは、溶接金属中の酸化物系介在物の分布に影響を及ぼす元素である。含有量が0.01%を超えると、酸化物系介在物の密度が増加し、プレス成形中において酸化物系介在物を伝播する割れが起こる。このため、その上限を0.01%とする。
C、Si、及びSは、溶接時の溶融池(溶融金属)の流動性に影響を及ぼす元素である。具体的には、Si及びSは、その含有量が多いほど、溶融池の流動性が向上する。一方、Cは、その含有量が少ないほど、溶融池の流動性が向上する。
本実施形態に係る溶接継手では、C、Si、及びSが溶融池の流動性に及ぼす影響の大きさを考慮して得られた下記(1)式で示される溶融池流動性指標αが0.3~3.0となるように溶接金属の成分を制御する。
尚、Si、S、Cは、溶接金属での各元素の含有量(質量%)を意味する。
溶融池流動性指標α=Si+200×S-2.7×C・・・(1)式
一方、溶融池流動性指標αが3.0を超える場合、ポロシティ分布密度が増加する傾向となる。この理由は定かではないが、溶接時に溶接金属内に取り込まれる気体の量が増加している可能性がある。従って、溶融池流動性指標αは3.0以下であり、2.5以下であることが好ましく、1.8以下であることが更に好ましい。
Ni:0~10.0%
Mo:0~1.0%
Cr、NiおよびMoは、金属組織を制御するために鋼板に含有され、その結果、溶接金属に含有される元素である。
Cr、Ni、Moの下限値は0%であるが、添加する効果を確実に得るためには0.0001%を下限値とすることが好ましい。
一方、溶接金属のCr含有量が5.0%を、Ni含有量が10.0%を、Mo含有量が1.0%をそれぞれ超えると、溶接金属が脆化して溶接金属において割れが発生する場合がある。したがって、Cr含有量は5.0%以下、Ni含有量は10.0%以下、Mo含有量は1.0%以下とする。
Cr、Ni、Moの含有量が上記範囲内であっても、下記の(2)式で表される溶接金属のMs点が250℃未満になると、プレス成形時に溶接金属において割れが発生する場合がある。この原因は定かではないが、溶接金属の金属組織の構成が影響している可能性がある。すなわち、Ms点が250℃未満になると、溶接金属中のマルテンサイトのうち、bct構造のマルテンサイトの比率が高くなる。これにより、溶接金属において割れが発生しやすくなる可能性がある。したがって、Cr、NiおよびMoの群から選択される1種以上を溶接金属に含有させる場合には、下記の(2)式によって表されるMsの値が250以上になるように各元素の含有量を決定することが好ましく、280以上になるように各元素の含有量を決定することが更に好ましい。
Ms=561-474×C-33×Mn-17×Ni-17×Cr-21×Mo ・・・(2)式
ただし、(2)式において、各元素記号は溶接金属に含まれる各元素の含有量(質量%)を示し、含有されない場合はゼロとする。
Cuは、後述するように金属組織の構成を制御するために鋼板に含有され、その結果、溶接金属に含有される元素である。しかしながら、Cu含有量が1.0%を超えると溶接金属が脆化し、溶接継手をプレス成形する際に割れが発生する場合がある。したがって、Cu含有量は1.0%以下にすることが好ましい。Cuの下限値は0%であるが、添加する効果を確実に得るためには0.0001%を下限値とすることが好ましい。
Nb、TiおよびVは、析出強化元素として鋼板の強度を向上させる効果を有し、レーザー溶接後の溶接金属内の結晶粒と溶接熱影響部の結晶粒とを微細化するために用いられる。しかし、Nb、TiおよびVの合計含有量が0.2%を超えると、溶接金属中において酸化物を形成し、該酸化物がプレス成形時に割れの起点となるおそれがある。したがって、Nb、TiおよびVの合計含有量は、0.2%以下にすることが好ましい。Nb、TiおよびVの合計含有量の下限値は0%であるが、添加する効果を確実に得るためには0.0001%を下限値とすることが好ましい。
CaおよびREMは、溶接継手の素材鋼板および溶接金属において割れの起点となりうる介在物を制御する効果を有する。しかし、CaおよびREMの合計含有量が0.01%を超えると、溶接金属中において酸化物を形成し、該酸化物がプレス成形時に割れの起点となるおそれがある。したがって、CaおよびREMの合計含有量は、0.01%以下にすることが好ましい。CaおよびREMの合計含有量の下限値は0%であるが、添加する効果を確実に得るためには0.0001%を下限値とすることが好ましい。
なお、「REM」とは、Sc、Yおよびランタノイドの合計17元素の総称であり、REMの含有量は、REMのうちの1種以上の元素の合計含有量を意味する。また、「ランタノイド」とは、LaからLuまでの合計15元素の総称である。
Bは、溶接金属の強度および靭性を向上させる効果を有する。しかし、B含有量が0.01%を超えると、溶接金属中において硼化物を形成し、該硼化物がプレス成形時に割れの起点となるおそれがある。したがって、B含有量は、0.01%以下にすることが好ましい。Bの下限値は0%であるが、添加する効果を確実に得るためには0.0001%を下限値とすることが好ましい。
本実施形態に係る溶接継手の溶接金属は、たとえば、上記の元素を含有し、残部はFeおよび不純物からなる。「不純物」とは、鋼材を工業的に製造する際に、鉱石、スクラップ等の原料その他の要因により混入する成分を意味する。また、後述するように、溶接継手の素材鋼板としてめっき鋼板を用いる場合には、めっき材料の元素が不純物として溶接金属に含まれる。
溶接金属の化学組成は、以下のようにして求める。まず、溶接継手から、溶接金属のみを切断して試料を切り出すか、研磨により溶接部を現出させる。この試料について、JIS G0321(2010)の表1に記載の規格に従って定量分析を行う。これにより、溶接金属の化学組成を求めることができる。
溶接金属の化学組成は、該溶接金属を介して互いに接合された複数の鋼板(母材)の平均組成及び溶接条件に左右される。従って、複数の鋼板の平均組成は、上述の溶接金属の化学組成の範囲であることが好ましい。尚、溶接時に溶接ワイヤーやインサートメタルを用いることで、複数の鋼板の平均組成が上述の溶接金属の化学組成の範囲でなくても溶接金属の化学組成を調節することが可能である。酸素量については、溶接条件を調整することで所望の範囲とすることが可能である。
複数の鋼板の平均組成は、各元素の平均含有量を下記式によって算出して求める。
ただし、上記(3)式において、Xaveは任意の元素Xの平均含有量を示し、tkはn枚の鋼板のうちのk番目の鋼板の板厚を示し、Xkは上記k番目の鋼板に含まれる元素Xの含有量を示す。
Xave=(tA・XA+tB・XB)/(tA+tB) (4)式
本実施形態に係る溶接継手においては、上述の構成を有する鋼板の表面にめっき処理を施してもよい。溶接継手の素材としてめっき鋼板を用いることによって、溶接金属の拡散性水素量を低減できる。この理由は、溶接熱により蒸発しためっき成分が気体状態で溶融金属部をシールドし、その結果、溶融金属周囲の空間に存在する水分の溶融金属中への侵入を抑制するためと推定される。従って、溶接継手を構成する複数の鋼板のうちの少なくとも一つをめっき鋼板とすることが好ましく、全てをめっき鋼板とすることがより好ましい。めっきの種類は特に限定されず、溶融めっき、合金化溶融めっきおよび電気めっき等の種々のめっきを用いることができる。また、めっきの厚さも特に限定されない。めっき材料としては、たとえば、Zn、Ni、Al、FeおよびSnを用いることができる。また、合金めっきを用いてもよい。具体的には、Zn-Sn、Zn-Al-Mg、またはZn-Al-Mg-Si等の組成を有する合金めっきを用いてもよい。なお、溶接継手の素材鋼板としてめっき鋼板を用いる場合には、めっき材料の元素が不純物として溶接金属の化学組成に含まれることがある。
上述したように、溶接継手のプレス加工時の溶接金属割れは、非拡散性水素の集積により内圧が高められたポロシティを起点とする割れであると考えられる。従って、ポロシティ内の非拡散性水素を規定することが出来れば、溶接継手のプレス加工時の溶接金属割れを抑制できる筈である。しかしながら、ポロシティ内の非拡散性水素を測定することは非現実的である。本発明者らは、ポロシティ内の非拡散性水素は金属格子中の拡散性水素に、多少の時間差はあるものの、互いに相関を有することを発見した。
より詳細に説明すると、図2Aに示す通り、溶接直後では、溶接時の大気中のH2Oの解離により、拡散性水素が金属格子中に過剰に残留した状態にある。その後、これらの拡散性水素は、拡散初期段階を示す図2Bに示す通り、(1)鋼板表面から排出される、(2)ポロシティ内部に集積される、或いは、(3)酸化物系介在物にトラップされる。更にその後、拡散後期段階を示す図2Cに示す通り、ポロシティ内部に集積された非拡散性水素についても時間の経過と共に金属格子外に排出される。従って、拡散初期段階及び拡散後期段階では、ポロシティ内の非拡散性水素の量は金属格子中の拡散性水素の量に相関する。
また、溶接金属中における拡散性水素量が一定の場合には、溶接金属の硬さが大きいほど、溶接金属において割れが発生しやすくなる。言い換えると、溶接金属における割れの発生を防止できる拡散性水素量の限界値(限界拡散性水素量)は、溶接金属の硬さが大きいほど小さくなる。
そこで、本発明者らは、溶接後に10~100℃の温度域で規定保持時間t=7000×C-400(min)を保持した後に測定して得られる溶接金属中の拡散性水素量CH(mass ppm)の量が下記(5)式を満たしていれば、溶接継手のプレス加工時の溶接金属割れを好適に抑制できることを発見した。
CH≦3.570-0.0066×HVWM ・・・(5)式
ここで、HVWMは、溶接金属のビッカース硬さでの平均硬さである。
溶接金属の金属組織は、プレス成形時の割れ挙動に影響を及ぼす因子である。原因は定かではないが、本発明者らの調査の結果、溶接金属の主たる金属組織がbct(体心正方)構造のマルテンサイトであると、プレス成形時に溶接金属において割れが発生しやすくなることがわかった。そのため、溶接金属の主たる金属組織は、bcc構造のマルテンサイトであることが好ましい。bcc構造のマルテンサイトとしては、炭化物が存在しないマルテンサイトであってもよく、鉄炭化物が析出した焼き戻しマルテンサイトであってもよい。残部組織は、ベイナイトおよび残留オーステナイトの1種または2種であってもよい。
ここで、主たる金属組織とは、面積率で80%以上の金属組織のことをいう。溶接金属の金属組織は、bcc(体心立方)構造のマルテンサイトを面積率で90%以上有することが好ましい。なお、金属組織は、たとえば、SEMまたは透過型電子顕微鏡(TEM)によって観察することにより特定できる。また、マルテンサイトの結晶構造は、たとえば、X線回折法によって特定することができる。具体的には、X線回折法により{100}面のa軸とc軸の格子定数を測定し、軸比c/aから立方晶(bcc)か正方晶(bct)かを判断する。c/a値が1.007以下の場合をマルテンサイトの構造がbcc構造であるとする。
本発明者らは、上述の構成を有する溶接継手を製造するための好ましい条件について種々の研究を行った。具体的には、溶接金属中の拡散性水素量およびポロシティ量を制御するための方法について研究を行った。その結果、溶接雰囲気の絶対湿度、溶接速度、および成形前の溶接継手の熱処理条件を適切に設定することによって、溶接金属中の拡散性水素量およびポロシティ量を制御できることがわかった。以下、溶接継手の製造条件について詳しく説明する。
レーザー溶接時の絶対湿度は、溶接金属中の拡散性水素量に影響を及ぼす。具体的には、絶対湿度が25g/m3を超えると溶接金属中の拡散性水素量が過大となり、プレス成形前に溶接金属において遅れ破壊が発生する場合がある。また、絶対湿度が25g/m3を超えると、プレス成形前に所定時間の熱処理を行ったとしても、溶接金属に残留する拡散性水素量を十分に低減できない。このため、プレス成形前に遅れ破壊が発生しない場合でも、プレス成形時に割れが発生しやすくなる。このため、レーザー溶接時の絶対湿度は、25g/m3以下とし、好ましくは、20g/m3以下とする。
一方、絶対湿度が5g/m2未満であると、水素をトラップすることでポロシティ内への水素の集積を妨げる効果のある酸化物系介在物の分布密度が少なくなる。これは、湿分の減少により、溶接中に起こるH2Oの解離反応(H2O→2H+O)により生じるO原子の量が減少し、その結果、溶融金属と酸化反応するOの量が減少したためと考えられる。従って、絶対湿度は5g/m2以上であり、7g/m2以上であることが好ましく、10g/m2以上であることが更に好ましい。
レーザー溶接速度は、溶接金属の拡散性水素量とポロシティ量に影響を及ぼす因子である。レーザー溶接速度が8m/minを超えると、溶接金属の拡散性水素量および/またはポロシティ量が高くなり、溶接金属において割れが発生しやすくなる。このため、レーザー溶接速度は、8m/min以下であり、6m/min以下であることが好ましく、5m/min以下であることが更に好ましい。
レーザー溶接終了後かつプレス成形前において、溶接金属中の拡散性水素量を低減するために、溶接継手を所定の温度で保持する。保持温度が10℃未満であると、拡散性水素量を十分に低減できず、保持温度が100℃を超えると、溶接金属以外の鋼板の機械的特性が変化してしまう。このため、レーザー溶接終了後かつプレス成形前における溶接継手は、10~100℃の温度域で保持することが好ましい。保持温度は、20℃以上であることが好ましく、80℃以下であることが好ましい。
レーザー溶接終了後かつプレス成形前における溶接継手の10~100℃の温度域での保持時間(min)は、溶接金属中の拡散性水素量に影響を与える。上記保持時間が、「7000×C-400」未満であると、溶接金属中の拡散性水素量を十分に低減できず、プレス成形時に溶接金属で割れが発生しやすくなる(ただし、Cは溶接金属におけるC含有量(質量%)を示す。)。そこで、下記の(6)式を満たすように保持時間tを設定し、より好ましくは下記の(7)式を満たすように保持時間tを設定する。
t(min)≧7000×C-400 ・・・(6)式
t(min)≧8000×C-400 ・・・(7)式
レーザー溶接終了後からかつプレス成形前における溶接継手の10~100℃の温度域での保持時間(min)が60分までの間は、溶接金属中の拡散性水素量が低くてもプレス成形時に溶接金属で割れが生じることがある。この理由は定かではないが、保持時間が60分までの間は、溶接金属内の水素濃度が偏在しており、拡散性水素量の平均値が低くても局所的に水素濃度が高い領域が存在することもあるためと推測される。従って、保持時間tは、上記(6)式又は(7)式による下限値設定に加え、60分、好ましくは100分、より好ましくは180分の下限設定をしてもよい。
(a)「鋼板の組合せ」
(b)「板厚(mm)」
(c)「溶接金属の化学組成(質量%)」
(d)「鋼板のMs」
(e)「指標α」・・・Si+200S-2.7Cで示される溶融池流動性指標
(f)「溶接速度(m/min)」
(g)「絶対湿度(g/m3)」・・・溶接雰囲気の絶対湿度
(h)「保持時間(min)」・・・溶接終了後かつプレス成形前における、30℃での溶接継手の保持時間
(i)「規定保持時間(min)」・・・t=7000×C-400で求められる時間
(j)「溶接金属の酸素量(質量%)」・・・溶接終了後の酸素量
尚、本実施例においては溶接ワイヤーやインサートメタルを使用していないため、溶接金属の化学組成は、酸素を除き、鋼板の平均組成とほぼ同一であった。
(k)「HVWM(HV)」・・・溶接金属の平均硬さ
(l)「ポロシティ分布密度(個/mm2)」・・・溶接金属中の直径2μm以上50μm以下のポロシティの分布密度
(m)「介在物分布密度(個/mm2)」・・・溶接金属中の直径3μm以上の酸化物系介在物の分布密度
(n)「CH(mass ppm)」・・・溶接金属中の拡散性水素量CH
(o)「(5)式の右辺値」・・・3.57-0.0066×HVWMの値
(p)「マルテンサイトの結晶構造」・・・溶接金属中のマルテンサイトの結晶構造
(q)「割れの有無」・・・保持時間経過時に行ったドローベンド試験による割れの有無
なお、全ての溶接継手1~57において、主たる金属組織は、マルテンサイトであった。表6、表7において、マルテンサイトの結晶構造をbccと示している溶接継手については、溶接金属の主たる金属組織がbcc構造のマルテンサイト組織であったことを意味し、bctと示している溶接継手は、溶接金属の主たる金属組織がbct構造のマルテンサイト組織であったことを意味する。
また、マルテンサイトの結晶構造は、X線回折法によって特定した。具体的には、X線回折法により{100}面のa軸とc軸の格子定数を測定し、軸比c/aから立方晶(bcc)か正方晶(bct)かを判断した。c/a値が1.007以下の場合をマルテンサイトの構造がbcc構造であるとした。
Aw=At×Ww/Wt・・・(8)式
Claims (13)
- 複数の鋼板の間に設けられた溶接金属を有するレーザー溶接継手であって、
前記溶接金属の化学組成が、質量%で、
C: 0.05~0.30%、
Si:0.005~3.0%、
Al:0.005~1.0%、
Mn:0.5~6.0%、
P:0超~0.04%、
S:0超~0.01%、
N:0超~0.01%、
O:0超~0.01%、
Cu:0~1.0%、
Nb+Ti+V:0~0.2%、
Ca+REM:0~0.01%、
B:0~0.01%、
Cr:0~5.0%、
Ni:0~10.0%、
Mo:0~1.0%、及び
残部:Feおよび不純物
を含むとともに、
0.3≦Si+200×S-2.7×C≦3.0を満たし、
前記溶接金属の平均硬さがビッカース硬さで350~540であり、
前記溶接金属では、直径2μm~50μmのポロシティの分布密度が5.0個/mm2以下であり、
前記溶接金属では、直径3μm以上の酸化物系介在物の分布密度が0.1~8.0個/mm2である
ことを特徴とするレーザー溶接継手。 - 前記溶接金属の化学組成が、質量%で、
Cu:0.0001~1.0%、
Nb+Ti+V:0.0001~0.2%、
Ca+REM:0.0001~0.01%、
B:0.0001~0.01%、
Cr:0.0001~5.0%、
Ni:0.0001~10.0%、及び
Mo:0.0001~1.0%、
の群から選択される少なくとも一種を含む
ことを特徴とする請求項1に記載のレーザー溶接継手。 - 前記溶接金属中の拡散性水素量CHが、単位mass ppmとして、下記の(1)式を満足する
ことを特徴とする請求項1又は2に記載のレーザー溶接継手。
CH≦3.570-0.0066×HVWM (1)式
ただし、(1)式においてHVWMは、前記溶接金属のビッカース硬さでの平均硬さを示す。 - 前記溶接金属の金属組織の80%以上がマルテンサイトであり、そのマルテンサイトの構造がbcc構造である
ことを特徴とする請求項1~3のいずれか一項に記載のレーザー溶接継手。 - 下記の(2)式によって表されるMsの値が250以上である
ことを特徴とする請求項1~4のいずれか一項に記載のレーザー溶接継手。
Ms=561-474×C-33×Mn-17×Ni-17×Cr-21×Mo (2)式 - 前記複数の鋼板のうちの少なくとも1つがめっき鋼板である
ことを特徴とする請求項1~5のいずれか一項に記載のレーザー溶接継手。 - 請求項1~6のいずれか一項に記載のレーザー溶接継手を有する
ことを特徴とする自動車部品。 - 請求項1~6のいずれか一項に記載のレーザー溶接継手の製造方法であって、
複数の鋼板を、絶対湿度が5~25g/m3以下の雰囲気下で8m/min以下の溶接速度でレーザー溶接することにより、前記複数の鋼板同士を接合する溶接金属を形成するレーザー溶接工程と、
溶接後の前記複数の鋼板を10~100℃の温度域で下記の(3)式で規定される時間保持する保持工程と、
を備え、
前記溶接金属の化学組成が、質量%で、
C: 0.05~0.30%、
Si:0.005~3.0%、
Al:0.005~1.0%、
Mn:0.5~6.0%、
P:0超~0.04%、
S:0超~0.01%、
N:0超~0.01%、
O:0超~0.01%、
Cu:0~1.0%、
Nb+Ti+V:0~0.2%、
Ca+REM:0~0.01%、
B:0~0.01%、
Cr:0~5.0%、
Ni:0~10.0%、
Mo:0~1.0%、及び
残部:Feおよび不純物
を含むとともに、
0.3≦Si+200×S-2.7×C≦3.0
を満たす
ことを特徴とするレーザー溶接継手の製造方法。
t≧7000×C-400 (3)式
ただし、(3)式においてtは単位を分とする時間を示す。 - 前記溶接金属の化学組成が、質量%で、
Cu:0.0001~1.0%、
Nb+Ti+V:0.0001~0.2%、
Ca+REM:0.0001~0.01%、
B:0.0001~0.01%、
Cr:0.0001~5.0%、
Ni:0.0001~10.0%、及び
Mo:0.0001~1.0%、
の群から選択される少なくとも一種を含む
ことを特徴とする請求項8に記載のレーザー溶接継手の製造方法。 - 下記の(4)式によって表されるMsの値が250以上である
ことを特徴とする請求項8又は9に記載のレーザー溶接継手の製造方法。
Ms=561-474×C-33×Mn-17×Ni-17×Cr-21×Mo (4)式 - 前記複数の鋼板のうちの少なくとも1つがめっき鋼板である
ことを特徴とする請求項8~10のいずれか一項に記載のレーザー溶接継手の製造方法。 - 請求項1~6のいずれか一項に記載のレーザー溶接継手にプレス成形を施す
ことを特徴とする自動車部品の製造方法。 - 請求項8~11のいずれか一項に記載の製造方法によって製造されたレーザー溶接継手にプレス成形を施す
ことを特徴とする自動車部品の製造方法。
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2964729A CA2964729C (en) | 2014-11-19 | 2015-11-19 | Laser welded joint, vehicle component, manufacturing method of laser welded joint, and manufacturing method of vehicle component |
JP2016560284A JP6399106B2 (ja) | 2014-11-19 | 2015-11-19 | レーザー溶接継手、自動車部品、レーザー溶接継手の製造方法および自動車部品の製造方法 |
MX2017006218A MX2017006218A (es) | 2014-11-19 | 2015-11-19 | Cordon soldado por laser, componente de vehiculo, metodo de fabricacion del cordon soldado por laser y metodo de fabricacion de componente de vehiculo. |
US15/523,874 US10697486B2 (en) | 2014-11-19 | 2015-11-19 | Laser welded joint, vehicle component, manufacturing method of laser welded joint, and manufacturing method of vehicle component |
BR112017008578A BR112017008578A2 (pt) | 2014-11-19 | 2015-11-19 | junta soldada a laser, componente de veículo, método de fabricação de junta soldada a laser e método de fabricação de componente de veículo |
KR1020177012386A KR101928227B1 (ko) | 2014-11-19 | 2015-11-19 | 레이저 용접 조인트, 자동차 부품, 레이저 용접 조인트의 제조 방법, 및 자동차 부품의 제조 방법 |
ES15862070T ES2749205T3 (es) | 2014-11-19 | 2015-11-19 | Junta soldada por láser, componente de vehículo, método de fabricación de junta soldada por láser y método de fabricación de componente de vehículo |
EP15862070.8A EP3222745B1 (en) | 2014-11-19 | 2015-11-19 | Laser welded joint, automotive part, method for producing laser welded joint, and method for manufacturing automotive part |
CN201580061499.XA CN107002191B (zh) | 2014-11-19 | 2015-11-19 | 激光焊接接头、汽车部件、激光焊接接头的制造方法及汽车部件的制造方法 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2014-234957 | 2014-11-19 | ||
JP2014234957 | 2014-11-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2016080488A1 true WO2016080488A1 (ja) | 2016-05-26 |
Family
ID=56014020
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2015/082553 WO2016080488A1 (ja) | 2014-11-19 | 2015-11-19 | レーザー溶接継手、自動車部品、レーザー溶接継手の製造方法および自動車部品の製造方法 |
Country Status (10)
Country | Link |
---|---|
US (1) | US10697486B2 (ja) |
EP (1) | EP3222745B1 (ja) |
JP (1) | JP6399106B2 (ja) |
KR (1) | KR101928227B1 (ja) |
CN (1) | CN107002191B (ja) |
BR (1) | BR112017008578A2 (ja) |
CA (1) | CA2964729C (ja) |
ES (1) | ES2749205T3 (ja) |
MX (1) | MX2017006218A (ja) |
WO (1) | WO2016080488A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2017177140A (ja) * | 2016-03-29 | 2017-10-05 | 新日鐵住金株式会社 | テーラードブランク材からなるプレス成形品の製造方法 |
WO2020059804A1 (ja) * | 2018-09-19 | 2020-03-26 | 日本製鉄株式会社 | テーラードブランク、テーラードブランクの製造方法、プレス成形品、及び、プレス成形品の製造方法 |
JP2022515425A (ja) * | 2018-12-24 | 2022-02-18 | アルセロールミタル | 溶接鋼ブランク及び関連する溶接鋼ブランクを生産するための方法 |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2013243947A1 (en) | 2012-04-02 | 2014-10-30 | Moderna Therapeutics, Inc. | Modified polynucleotides for the production of proteins |
CN106133165B (zh) * | 2014-03-31 | 2019-03-08 | 杰富意钢铁株式会社 | 焊接接头 |
WO2019102255A1 (en) | 2017-11-24 | 2019-05-31 | Arcelormittal | Method of producing a welded steel blank with the provision of a filler wire having a defined carbon content, associated welded blank, method of producing a welded part with hot press-formed and cooled steel part and associated part |
CN109609747B (zh) * | 2018-12-11 | 2022-01-25 | 信达科创(唐山)石油设备有限公司 | 一种连续油管的均质处理工艺 |
JP7143938B2 (ja) * | 2019-03-27 | 2022-09-29 | 日本製鉄株式会社 | 自動車用足回り部品 |
JP7143937B2 (ja) * | 2019-03-27 | 2022-09-29 | 日本製鉄株式会社 | 自動車用足回り部品 |
EP3885070A1 (de) * | 2020-03-26 | 2021-09-29 | Voestalpine Böhler Welding Austria GmbH | Schweissgut sowie metallpulverfülldraht zur herstellung eines schweissguts |
KR20230021319A (ko) * | 2021-08-05 | 2023-02-14 | 주식회사 포스코 | 테일러 웰디드 블랭크, 열간성형부재 및 이들의 제조방법 |
KR20230040512A (ko) * | 2021-09-16 | 2023-03-23 | 주식회사 포스코 | 피로저항특성 및 용접부의 잔류응력으로 인한 변형에 대한 저항성이 우수한 가스 실드 아크 용접용 와이어와 용접부재 및 그 제조방법 |
CN117583789B (zh) * | 2024-01-17 | 2024-03-29 | 云南渝霖模板制造有限公司 | 一种挂篮自动化焊接装置及其焊接方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10146686A (ja) * | 1996-11-19 | 1998-06-02 | Sumitomo Metal Ind Ltd | 薄鋼板の軟質継手の製造方法 |
JPH11293398A (ja) * | 1998-04-06 | 1999-10-26 | Kawasaki Steel Corp | 高密度エネルギービーム溶接に適した熱延鋼板およびその製造方法 |
JPH11343538A (ja) * | 1998-05-29 | 1999-12-14 | Kawasaki Steel Corp | 高密度エネルギービーム溶接に適した冷延鋼板およびその製造方法 |
JP2000109946A (ja) * | 1998-10-05 | 2000-04-18 | Nkk Corp | レーザ溶接性に優れた造船用鋼板 |
JP2012115840A (ja) * | 2010-11-29 | 2012-06-21 | Jfe Steel Corp | 溶接金属部の靭性に優れた鋼材のレーザ溶接継手 |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3240627B2 (ja) * | 1991-03-27 | 2001-12-17 | 日産自動車株式会社 | 等速ジョイント部品の製造方法 |
JPH07328703A (ja) * | 1994-04-14 | 1995-12-19 | Nippon Steel Corp | 表面性状と溶接性に優れた複層鋼板の製造法 |
JP3519966B2 (ja) * | 1999-01-07 | 2004-04-19 | 新日本製鐵株式会社 | 低温靱性に優れた超高強度ラインパイプおよびその製造法 |
JP4267183B2 (ja) * | 2000-06-19 | 2009-05-27 | 新日本製鐵株式会社 | 疲労強度特性に優れたレーザーまたは電子ビーム溶接継ぎ手を備えた構造物及びそれらの製造法 |
FR2865151A1 (fr) * | 2004-01-21 | 2005-07-22 | Air Liquide | Procede de soudage par laser d'acier, en particulier ferritique |
JP4403145B2 (ja) | 2005-02-25 | 2010-01-20 | 新日本製鐵株式会社 | 溶接金属の耐水素脆化割れ特性に優れた高強度溶接鋼管とその製造方法 |
JP4508087B2 (ja) | 2005-11-17 | 2010-07-21 | 住友金属工業株式会社 | 連続鋳造方法および連続鋳造鋳片 |
CN101680068A (zh) * | 2008-03-31 | 2010-03-24 | 新日本制铁株式会社 | 焊接接头部的耐再热脆化性和韧性优良的耐火钢材及其制造方法 |
JP4903918B1 (ja) * | 2010-06-07 | 2012-03-28 | 新日本製鐵株式会社 | 超高強度溶接継手およびその製造方法 |
WO2012070360A1 (ja) * | 2010-11-22 | 2012-05-31 | 新日本製鐵株式会社 | 電子ビーム溶接継手及び電子ビーム溶接用鋼材とその製造方法 |
KR101582782B1 (ko) * | 2010-12-22 | 2016-01-05 | 가부시키가이샤 고베 세이코쇼 | 용접 솔리드 와이어 및 용접 금속 |
JP5607002B2 (ja) | 2011-02-02 | 2014-10-15 | 株式会社神戸製鋼所 | 耐水素脆化感受性に優れた溶接金属 |
-
2015
- 2015-11-19 MX MX2017006218A patent/MX2017006218A/es unknown
- 2015-11-19 WO PCT/JP2015/082553 patent/WO2016080488A1/ja active Application Filing
- 2015-11-19 CA CA2964729A patent/CA2964729C/en not_active Expired - Fee Related
- 2015-11-19 JP JP2016560284A patent/JP6399106B2/ja active Active
- 2015-11-19 CN CN201580061499.XA patent/CN107002191B/zh active Active
- 2015-11-19 EP EP15862070.8A patent/EP3222745B1/en active Active
- 2015-11-19 KR KR1020177012386A patent/KR101928227B1/ko active IP Right Grant
- 2015-11-19 BR BR112017008578A patent/BR112017008578A2/pt not_active Application Discontinuation
- 2015-11-19 US US15/523,874 patent/US10697486B2/en active Active
- 2015-11-19 ES ES15862070T patent/ES2749205T3/es active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10146686A (ja) * | 1996-11-19 | 1998-06-02 | Sumitomo Metal Ind Ltd | 薄鋼板の軟質継手の製造方法 |
JPH11293398A (ja) * | 1998-04-06 | 1999-10-26 | Kawasaki Steel Corp | 高密度エネルギービーム溶接に適した熱延鋼板およびその製造方法 |
JPH11343538A (ja) * | 1998-05-29 | 1999-12-14 | Kawasaki Steel Corp | 高密度エネルギービーム溶接に適した冷延鋼板およびその製造方法 |
JP2000109946A (ja) * | 1998-10-05 | 2000-04-18 | Nkk Corp | レーザ溶接性に優れた造船用鋼板 |
JP2012115840A (ja) * | 2010-11-29 | 2012-06-21 | Jfe Steel Corp | 溶接金属部の靭性に優れた鋼材のレーザ溶接継手 |
Non-Patent Citations (1)
Title |
---|
See also references of EP3222745A4 * |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2017177140A (ja) * | 2016-03-29 | 2017-10-05 | 新日鐵住金株式会社 | テーラードブランク材からなるプレス成形品の製造方法 |
WO2020059804A1 (ja) * | 2018-09-19 | 2020-03-26 | 日本製鉄株式会社 | テーラードブランク、テーラードブランクの製造方法、プレス成形品、及び、プレス成形品の製造方法 |
CN112739471A (zh) * | 2018-09-19 | 2021-04-30 | 日本制铁株式会社 | 拼焊板、拼焊板的制造方法、压力成形品及压力成形品的制造方法 |
JPWO2020059804A1 (ja) * | 2018-09-19 | 2021-09-30 | 日本製鉄株式会社 | テーラードブランク、テーラードブランクの製造方法、プレス成形品、及び、プレス成形品の製造方法 |
JP7422080B2 (ja) | 2018-09-19 | 2024-01-25 | 日本製鉄株式会社 | テーラードブランク、テーラードブランクの製造方法、プレス成形品、及び、プレス成形品の製造方法 |
US11945053B2 (en) | 2018-09-19 | 2024-04-02 | Nippon Steel Corporation | Tailored blank, tailored blank manufacturing method, stamped part, and stamped part manufacturing method |
JP2022515425A (ja) * | 2018-12-24 | 2022-02-18 | アルセロールミタル | 溶接鋼ブランク及び関連する溶接鋼ブランクを生産するための方法 |
KR20230003628A (ko) * | 2018-12-24 | 2023-01-06 | 아르셀러미탈 | 용접된 강 블랭크를 제조하기 위한 방법 및 연관된 용접된 강 블랭크 |
JP7337934B2 (ja) | 2018-12-24 | 2023-09-04 | アルセロールミタル | 溶接鋼ブランク及び関連する溶接鋼ブランクを生産するための方法 |
KR102644413B1 (ko) | 2018-12-24 | 2024-03-06 | 아르셀러미탈 | 용접된 강 블랭크를 제조하기 위한 방법 및 연관된 용접된 강 블랭크 |
Also Published As
Publication number | Publication date |
---|---|
CN107002191B (zh) | 2018-10-09 |
JPWO2016080488A1 (ja) | 2017-09-14 |
EP3222745B1 (en) | 2019-08-21 |
MX2017006218A (es) | 2017-07-31 |
CA2964729C (en) | 2020-03-10 |
US20170350434A1 (en) | 2017-12-07 |
BR112017008578A2 (pt) | 2017-12-26 |
EP3222745A1 (en) | 2017-09-27 |
US10697486B2 (en) | 2020-06-30 |
EP3222745A4 (en) | 2018-07-18 |
KR20170068531A (ko) | 2017-06-19 |
KR101928227B1 (ko) | 2018-12-11 |
CN107002191A (zh) | 2017-08-01 |
ES2749205T3 (es) | 2020-03-19 |
JP6399106B2 (ja) | 2018-10-03 |
CA2964729A1 (en) | 2016-05-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6399106B2 (ja) | レーザー溶接継手、自動車部品、レーザー溶接継手の製造方法および自動車部品の製造方法 | |
CN111492075B (zh) | 钢板、热浸镀锌钢板和合金化热浸镀锌钢板 | |
JP6787466B2 (ja) | 高強度亜鉛めっき鋼板の製造方法、及び高強度部材の製造方法 | |
KR102284770B1 (ko) | 가공성이 뛰어난 용융 Zn-Al-Mg계 도금 강판 및 그 제조 방법 | |
JP6777173B2 (ja) | スポット溶接用高強度亜鉛めっき鋼板 | |
KR101721352B1 (ko) | 내 지연 파괴 특성과 저온 인성이 우수한 고강도 강판 및 그것을 사용하여 제조한 고강도 부재 | |
KR20140002740A (ko) | 용융 Zn-Al-Mg계 도금 강판 및 제조방법 | |
JP5264235B2 (ja) | 耐溶融金属脆化割れ性に優れた高降伏比型Zn−Al−Mg系めっき鋼板およびその製造方法 | |
JP4317491B2 (ja) | 熱間プレス用鋼板 | |
JP4009313B2 (ja) | 溶接性に優れた高強度鋼材およびその製造方法 | |
JP2010235989A (ja) | 耐溶融金属脆化特性に優れた高強度Zn−Al−Mg系めっき鋼板およびその製造方法 | |
WO2023054717A1 (ja) | 鋼溶接部材 | |
JP6801496B2 (ja) | 曲げ加工性に優れた高強度溶融Zn−Al−Mg系めっき鋼板及びその製造方法 | |
JP2018145500A (ja) | 曲げ加工性に優れた自動車部品用高強度溶融Zn−Al−Mg系めっき鋼板及びそれを用いた自動車部品 | |
JP2021155775A (ja) | 摩擦圧接用鋼板、複合部材および自動車用部材 | |
KR20240007934A (ko) | 고강도 아연 도금 강판 및 부재 그리고 그들의 제조 방법 | |
JP2018145504A (ja) | 曲げ加工性に優れた建築部材用高強度溶融Zn−Al−Mg系めっき鋼板及びそれを用いた建築部材 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 15862070 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2016560284 Country of ref document: JP Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 2964729 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 15523874 Country of ref document: US |
|
REEP | Request for entry into the european phase |
Ref document number: 2015862070 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 20177012386 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: MX/A/2017/006218 Country of ref document: MX |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
REG | Reference to national code |
Ref country code: BR Ref legal event code: B01A Ref document number: 112017008578 Country of ref document: BR |
|
ENP | Entry into the national phase |
Ref document number: 112017008578 Country of ref document: BR Kind code of ref document: A2 Effective date: 20170426 |