Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
  • B23K11/3009—Pressure electrodes
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/10—Spot welding; Stitch welding
  • B23K11/11—Spot 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/16—Resistance welding; Severing by resistance heating taking account of the properties of the material to be welded
  • B23K11/18—Resistance welding; Severing by resistance heating taking account of the properties of the material to be welded of non-ferrous metals
  • B23K11/185—Resistance welding; Severing by resistance heating taking account of the properties of the material to be welded of non-ferrous metals of aluminium or aluminium alloys
• • 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
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
  • B23K11/3036—Roller electrodes
• • 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
  • B23K35/0205—Non-consumable electrodes; C-electrodes
• • 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
  • B23K35/0288—Welding studs
• • 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
  • B23K35/222—Non-consumable electrodes
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/02—Pretreatment of the material to be coated
  • C23C16/0272—Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/26—Deposition of carbon only
  • C23C16/27—Diamond only
  • C23C16/278—Diamond only doping or introduction of a secondary phase in the diamond
• • 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
  • B23K2103/10—Aluminium or alloys thereof

Definitions

• the invention relates to a welding electrode for resistance welding according to the preamble of patent claim 1. It also relates to the use of such a welding electrode.
• Welding electrodes for resistance welding in particular for resistance spot welding, are known, for example, from J.F. Key, T.H. Courtney:
• Welding electrodes for resistance spot welding usually have a cap as a welding tool, which can be plugged onto an electrode holder of a resistance spot welding device.
• a washer is used as a welding tool for roller seam welding.
• Such welding electrodes are made, for example, from sintered CUAI 2 O3, from CuCr or CuCrZr alloys.
• the object of the invention is to eliminate the disadvantages of the prior art.
• a universal welding electrode is to be specified with which a large number of resistance welded connections or large seam lengths between metal sheets is possible.
• a use of the welding electrode is to be specified.
• a welding electrode for resistance welding in which the contact surface is formed from diamond doped with boron and / or phosphorus.
• the proposed welding electrode it is surprisingly possible to produce more than 1,400 welded connections, in particular spot welded connections, between metal sheets, in particular aluminum sheets, without sticking.
• a passivation layer of Al2O3 formed on the surface of the aluminum sheets is mechanically broken through at least in sections, so that the diamond layer immediately meets the metallic Aluminum comes into contact.
• the contact resistance between the welding electrode and the aluminum sheet can be significantly reduced. This in turn prevents the aluminum sheet from melting in an area to the contact surface of the welding electrode and thus from sticking to the welding electrode.
• the diamond is doped with 500 to 20,000 ppm boron, preferably 2,000 to 10,000 ppm boron.
• the diamond can additionally or alternatively also be doped with 500 to 20,000 ppm phosphorus.
• This enables a resistance welding process to be carried out with a current density of 30 kA / cm 2 and more. This corresponds to about 30 times the current density compared to the conventional resistance welding process when welding sheet steel.
• a current density of 1 kA / cm 2 is usually used there.
• the possibility of using a particularly high current density enables a resistance weld to be carried out quickly. In particular, undesired heating of large areas of the workpieces to be welded is avoided.
• the diamond is produced as a diamond layer by means of a CVD process.
• the diamond layer is deposited in situ on the welding electrode from the gas phase. It has been shown that a diamond layer produced in this way has surprisingly good durability even under the extreme conditions of resistance welding.
• the diamond layer expediently has a thickness of 0.5 to 50 ⁇ m, preferably 1 to 10 ⁇ m.
• the diamond layer advantageously has a surface roughness with an average roughness depth Rz> 1 ⁇ m.
• a diamond layer with the above parameters is again characterized by an improved service life of the welding electrode.
• more than 50% of the contact surface is formed from facets which form the (1 1 1) or (001) planes of diamond crystals, preferably of fused diamond monocrystals.
• a growth zone of the diamond layer opposite the contact surface is expediently in contact with an intermediate layer on the cap side.
• the diamond single crystals extend predominantly in a [1 1 1] or [1 10] direction from the intermediate layer to the contact surface. I.e. the diamond single crystals extend from the intermediate layer to the contact surface in such a way that their grain boundaries predominantly run approximately perpendicular to the contact surface.
• a Dia mant Mrs with the proposed training is characterized by an excellent electrical and thermal conductivity.
• the intermediate layer is formed from a metal-carbide and / or nitride and / or boride compound of the first metal or a second metal different from the first metal.
• the first and / or the second metal forms, in particular, a carbide and / or nitride and / or boride compound which is stable up to a temperature of 800 ° C.
• the first and / or second metal can in particular be formed from one or more of the following elements: Cr, Ti, Nb, Mo, W, Ta.
• the intermediate layer can either can be formed directly in-situ during the CVD process or produced separately at a temperature of 600 ° C to 1,050 ° C.
• the first metal can be W, which contains Cu as an alloy component.
• the intermediate layer can be formed directly in the CVD process with which the diamond layer is deposited.
• WC is formed as an intermediate layer.
• the first metal is formed from W, which contains Fe as an alloy component.
• a TiN layer is deposited as an intermediate layer on the first metal in a first CVD process. This layer can be doped with B. The diamond layer is then deposited on the intermediate layer in a second CVD process.
• the first metal can preferably contain Cu, Fe or Ag as an alloy component.
• the welding tool can also be formed in sections from a third metal.
• the third metal can contain Cu as the main component.
• the welding tool can be produced, for example, from a W or Mo alloy, at least in a section forming the contact surface.
• the welding tool can also be made from a different metal, for example a Cu alloy. Such a welding tool can be manufactured relatively inexpensively.
• the welding tool can be a cap to be attached to an electrode holder of a resistance spot welding device.
• the welding tool can also be a disk for a roll seam welding device.
• the welding electrode according to the invention be used to produce a welded connection between the Use pieces made of a fourth metal with a passivating metal oxide layer.
• metal is to be understood generally in the context of the present invention. I.e. it can also be an alloy.
• the "fourth metal” is understood to mean a metal which spontaneously forms an oxide layer on its surface upon contact with air.
• the fourth metal is preferably selected from the following group: Al, Mg, Ni, Ti, Zn, Cr, Fe, Nb, Ta, Cu.
• AI2O3 is electrically insulating and has a high hardness (Vickers hardness approx. 2,000).
• the diamond layer provided on the welding electrode according to the invention has a higher hardness, namely a Vickers hardness of 7,000 to 10,000.
• the welding electrode according to the invention succeeds in breaking through the passivating layer forming on aluminum sheets, for example, so that direct electrical contact is established between the diamond layer and the metallically conductive section below the passivation layer.
• the welding electrode according to the invention can be used to produce a welded joint without the welding electrode sticking to the sheet metal to be welded.
• the effect described also applies to other fourth metals which form a passivating metal oxide layer, e.g. B. Al, Mg, Ni, Ti, Zn, Cr, Fe, Nb, Ta, Cu.
• the welded connection is expediently produced by means of resistance point welding. With a corresponding configuration of the welding electrode according to the invention, however, it is also conceivable to produce, for example, linear weld connections.
• FIG. 1 shows a plan view of a welding cap
• FIG. 2 shows a sectional view through the welding cap according to the section line A - A 'in FIG. 1,
• FIGS. 1 and 3 shows a view from below according to FIGS. 1 and
• FIG. 1 to 3 show a welding electrode in the form of a cap or welding cap.
• the welding electrode has a contact surface 1 which forms the free surface of a diamond layer 2.
• Reference numeral 3 denotes a portion which is formed, for example, from W or Mo or an alloy which contains Mo or W as a main component.
• the reference character 4 denotes an intermediate layer which, in the specific example, is essentially formed from WC or MoC. The intermediate layer 4 can be formed in situ during the production of the diamond layer 2 by means of a CVD method.
• the reference number 5 denotes a base section of the welding cap.
• the base section 5 can be made of a third metal which is different from the first metal forming the section 3.
• a third metal can be selected which is more cost-effective than the first metal used to produce the section 3.
• the base section 5 can be formed from pure copper or from a copper alloy, in particular CUAI2O3, CuCr or CuCrZr alloys. It can of course also be the case that the base section 5 is omitted and the cap is formed from the first metal that forms the section 3.
• section 3 can also be omitted.
• the welding cap is made from a conventional copper alloy, for example.
• the intermediate layer 4 must be applied separately in this case.
• the intermediate Layer can be formed from carbide-forming metals.
• the intermediate layer can contain Ti.
• the diamond layer 2 can then be deposited on such an intermediate layer 4 by means of a CVD method.
• Fig. 4 shows schematically the section 3, which is made of a W or Mo alloy.
• the alloy can have a grain boundary phase 6 which is formed from Fe, Ni, Co or Cu, for example.
• the diamond crystals 7 extending from the intermediate layer 4 are more than 50% diamond single crystals.
• the facets denoted by the reference numeral 8 of the diamond crystals 7 are formed either from the (111) or the (001) plane.
• the reference symbol P denotes arrows which reflect the direction of the current flow through the diamond layer 2. The current flow takes place parallel to the [111] and to the [110] direction of the diamond crystals 7.
• the contact surface 1 of the diamond layer 2 is formed by the entirety of the facets 8. Opposite the contact surface 1 is a workpiece 9 to be welded, which is made, for example, of an aluminum alloy.
• the workpiece 9 has a metal oxide layer 10 on its surface.
• the welding tool can also be formed from a disk instead of the cap.
• a disk instead of the cap.
• Such a washer is used in roller seam welding devices.
• the contact surface 1 is formed on the peripheral edge of the disk.
• the section 3 and possibly the Basisab section 5 are arranged in an analogous sequence to the cap shown in Fig. 1 to 3 at the disc lying radially on the inside.
• the diamond layer 2 is pressed against the metal oxide layer 10.
• a current density in the range from 5 to 60 kA / cm 2 preferably in the range from 10 to 20 kA / cm 2 , is generated.
• the workpiece 9 is welded to a further workpiece arranged opposite (not shown here), which is pressed against the workpiece 9 with a further welding electrode according to the invention (not shown here).

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Arc Welding In General (AREA)
• Resistance Welding (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

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• 2019
  • 2019-12-17 DE DE102019134727.0A patent/DE102019134727A1/de active Pending
• 2020
  • 2020-06-08 JP JP2021574171A patent/JP2022536384A/ja active Pending
  • 2020-06-08 CA CA3145982A patent/CA3145982A1/en active Pending
  • 2020-06-08 CN CN202080043477.1A patent/CN114007797A/zh active Pending
  • 2020-06-08 WO PCT/EP2020/065857 patent/WO2020249518A1/de unknown
  • 2020-06-08 EP EP20732530.9A patent/EP3983166A1/de active Pending
  • 2020-06-08 US US17/618,174 patent/US20220258275A1/en active Pending
  • 2020-06-08 BR BR112021025299A patent/BR112021025299A2/pt unknown
  • 2020-06-08 KR KR1020227000253A patent/KR20220024421A/ko unknown
  • 2020-06-08 MX MX2021015371A patent/MX2021015371A/es unknown

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