WO2001017722A1 - Method and device for welding sheet metal - Google Patents

Method and device for welding sheet metal Download PDF

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Publication number
WO2001017722A1
WO2001017722A1 PCT/FR2000/002419 FR0002419W WO0117722A1 WO 2001017722 A1 WO2001017722 A1 WO 2001017722A1 FR 0002419 W FR0002419 W FR 0002419W WO 0117722 A1 WO0117722 A1 WO 0117722A1
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WO
WIPO (PCT)
Prior art keywords
sheets
stack
sheet
temperature
zone
Prior art date
Application number
PCT/FR2000/002419
Other languages
French (fr)
Inventor
Bernard Criqui
Ludovic Goby
Patrick Habert
Jean-Paul Hardel
Original Assignee
Renault
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Renault filed Critical Renault
Publication of WO2001017722A1 publication Critical patent/WO2001017722A1/en

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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
    • B23K15/00—Electron-beam welding or cutting
    • B23K15/0033—Preliminary treatment
    • 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
    • B23K15/00—Electron-beam welding or cutting
    • B23K15/0046—Welding
    • B23K15/0093—Welding characterised by the properties of the materials to be welded
    • 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
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B23K26/24—Seam welding
    • B23K26/244—Overlap seam welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/32—Bonding taking account of the properties of the material involved
    • 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
    • B23K26/60—Preliminary treatment
    • 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
    • B23K2101/34—Coated articles, e.g. plated or painted; Surface treated articles
    • 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
    • B23K2103/02—Iron or ferrous alloys
    • B23K2103/04—Steel or steel 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
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/08—Non-ferrous metals or 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
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Definitions

  • the invention relates to a method and a device for welding a stack of coated sheets.
  • the invention relates more particularly to a method of welding a stack of sheets comprising at least one upper sheet and one lower sheet superposed, at least one of which is coated, at least on its internal face adjacent to the other sheet, by at least one metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the lowest melting temperature.
  • the invention also relates to a device for " laser welding of a stack of sheets coated with a metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the melting temperature 1a. weaker.
  • stacks are increasingly used in the fight against - corrosion, in particular in the automotive industry. Welding a stack of sheets therefore presents significant challenges, especially when it comes to welding a stack of steel sheets coated with zinc or zinc alloys.
  • Laser welding has the advantage of heating the materials very locally, and thus only causing slight deformations of the zinc coating and of the sheet metal. Laser welding has become a widely used technique for welding coated sheets. Several techniques can be implemented.
  • Another technique consists in heating the upper face of the upper sheet which will transmit, by conduction, the heat to the lower sheet until the bottom zone extends from said upper face to the lower face of the bottom sheet. This is the so-called transparency welding. With this technique, a problem appears in the weld joint. This is due to the vaporization temperature of the zinc
  • Bu lles of zinc vapors are formed, causing craters inside the weld, which affects the aesthetics and ⁇ especially the quality of the weld.
  • French patent application No. 95.02772 proposes to carry out, before welding, a stamping of the zone to be welded.
  • the international patent application WO-A1 -99/08829 proposes to form protuberances by local heating on the zone to be welded of the upper surface of the lower sheet. After having installed the upper sheet, the two sheets are welded by transparency.
  • the invention provides a method of the type described above, characterized in that it comprises the following successive steps: - stacking without play of the two sheets;
  • a relative movement is caused between the two heat sources and the stack of sheets so that the third zone moves relative to the stack of sheets to form a weld bead;
  • the two heat sources are connected to each other by means, making it possible to permanently adjust their relative positions, according to the direction of welding, as a function of the thickness of the sheets, of the coating and of the speed of the relative movement of the sources heat with respect to the stack of sheets;
  • the coating is an alloy containing zinc
  • the coating is zinc
  • the first heat source is a laser source
  • the second heat source is a laser source;
  • the first and second heat sources use a single laser source supplying each of the two sources.
  • the invention also provides a device for laser welding of a stack of sheets coated with a metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the melting temperature the weakest, characterized in that it comprises two coupled heat sources, and in that it makes it possible to weld the stack by transparency without a set of coated sheets.
  • the two heat sources use a single laser source supplying each of the two sources.
  • the invention therefore provides a method and a device for welding a stack of zinc-coated sheets by a weld which has good mechanical strength.
  • FIG. 1 shows a sectional view of two coated sheets
  • - Figure 2 shows the first step of u assembly process according to the invention of two coated sheets
  • FIG. 3 shows the temperature radient in a section along line 3-3 of Figure 2 of the assembly of the two sheets during the first step of the method according to the invention
  • FIG. 4 shows the second step of the assembly process according to the invention of the two coated sheets " ;
  • FIG. 5 shows the welded area in a section along line 5-5 as Figure 4 of the assembly of the two sheets during the second step of the method according to the invention
  • FIG. 6 shows a device according to the invention, implemented for welding coated sheets.
  • fig ure 1 In the ' description an upper, lower orientation is used, without limitation, in accordance with fig ure 1. There is shown on fig ure 1 a first sheet 1 0 and a second sheet 1 2.
  • the first upper sheet 1 0 has an upper face 14 and a lower face 16 which is coated with a layer of zinc 1 8.
  • the second lower sheet 12 has an upper face 20 and a lower face 22.
  • the upper face 20 is coated a layer of zinc 24.
  • the two faces 16 and 20 coated with zinc are said to be galvanized.
  • the two faces of each sheet are galvanized.
  • the thickness of the sheets 10 and 12 varies from 0.6 to 2 millimeters and the thickness of the zinc coating varies between 8 and 12 micrometers in the case of applications in the automotive construction field.
  • the invention consists in carrying out two successive stages of heating an area of the stack of sheets 1 0 and 12.
  • a first embodiment implements a first heating source 26 and a second heating source 28 to produce a substantially cylindrical weld point.
  • the two sheets 1 0 and 12 are superimposed without vertical play so that the zinc layers 18 and 24 are in contact in the areas to be welded.
  • a first step is illustrated in fig ures 2 and 3 implements the first heating source 26.
  • preheating by radiation of an energy beam ie a first impact zone 27 of substantially circular shape of diameter D 1 of the upper face 14 of the first sheet 1 0.
  • the heat transfer r is done by conduction rapid thus ensuring a slight temperature difference between that of the zone 27 of the upper surface 14 and that at the welding interface between the faces 16 and 24.
  • Preheating continues until a temperature above the zinc evaporation temperature, that is to say greater than 900 ° C is reached at the interface of the zinc layers 1 8 and 24.
  • the temperature of the sheets 1 0 and 12 near the interface remains , meanwhile, at a temperature below the melting temperature for welding, which in the case of steel is greater than 1500 ° C.
  • This first step ensures the evacuation of zinc vapors outside the future welding zone.
  • a temperature T1 corresponds to the temperature of vaporization of the zinc and a temperature T2 corresponds to a temperature below the melting temperature of the steel.
  • the zinc and the zinc vapor are then evacuated from a second zone of diameter D2 greater than the diameter of the welding point to be produced at the inside.
  • the first heating source 26 is a laser source such as a so-called YAG or C0 2 source or a laser diode.
  • a laser diode is suitable for this first step. Indeed, it makes it possible to heat an area 27 of 2 or 3 mm in diameter, unlike other laser sources which focus on a smaller area.
  • the use of a YAG laser source is more suitable than the use of a C0 2 laser source.
  • the absorption coefficient of the steel varies as a function of the wavelength of the incident beam. It decreases when the wavelength of the radiation increases.
  • the absorption coefficient of the sheet for radiation emitted by the YAG laser source of 1 micrometer in wavelength is around 20 to 30%.
  • the wavelength of the radiation emitted by the source C0 2 is 10 micrometers or ten times greater than that of the radiation emitted by the source YAG, the absorption coefficient of the sheet then being of the order of 10 to 1 5%.
  • the heating source 26 When the heating source 26 is a first laser source, it emits through an optic 32 a laser beam which is strongly absorbed by the first sheet 1 0.
  • a second step illustrated in FIGS. 4 and 5 is implemented after a determined time. This determined time must be sufficient to allow cooling and condensation of the zinc vapors beyond the second zone of diameter D2, in accordance with FIG. 5, greater than the diameter of the subsequent welding point.
  • control of the welding penetration during the second heating step is obtained from a constant value of residual temperature of the first stage in the assembly of the two sheets 10 and 12.
  • the second heating source 28 allows for example the welding with high energy density ie according to a technique known from the state of the art called "key-hole" welding.
  • an impact zone 40 of the energy beam 36 on the upper face 14 of the first sheet 10 has a diameter D4 less than the diameter D 1 of the first zone 27 heated during the first step .
  • the transfer by thermal conduction allows the two sheets 10 and 12 to be melted in a third zone 42.
  • This third zone 42 has a diameter D3 at the interface between the first sheet 10 and the second sheet 12 which is less than the diameter D2 corresponding to the zone in which the zinc was removed during the first stage.
  • the third zone 42 is a weld free from any porosity and its mechanical strength is maximum.
  • the second heating source 28 is a YAG or C02 laser source having a power of between 2 and 6 kW depending on the welding parameters.
  • the use of one or other of the laser sources is equivalent. Indeed, the implementation of it welding in keyhole overcomes the absorption coefficient of the sheets. The energy yields of the two laser sources are similar. If the second heating source 28 is a second laser source, it emits through an optic 34 a beam 36 with a higher energy density than the first heating source 26.
  • the heating sources 26 and 28 are a single heating source, the power, the focal distance and / or the diameter of the heated area being varied.
  • the first heating source 26 and the second heating source 28 are used to produce a weld bead 44.
  • the two heating sources 26 and 28 are fixed to the same robotic arm 46 which enables the shape of the determined weld bead 44 to be precisely monitored.
  • the powers of the two sources 26 and 28 are adjusted so as to carry out the two preceding stages successively in a single pass.
  • the second heating source 28 is fixed to a slave slide 48.
  • the latter makes it possible to adjust the distance between the first 26 and the second 28 heating source so as to maintain the same parameters for implementing the method by taking into account the variations in curvature of the trajectory of the weld bead 44 and / or the thickness of the two sheets 1 0 and 12.
  • the control of the penetration of welding during the second step is obtained from a constant value of residual temperature in the stack of sheets 1 0 and 12, the residual temperature value is maintained by setting the distance between the sources to compensate for variations in speed and differences in thickness.
  • the welding speed and / or the distance between the two heating sources must be modified.
  • this second embodiment allows, as in the first, to remove the zinc from the third welded zone 42.
  • the absence of projections and therefore the possibility of bringing the two heating sources closer together makes it possible to increase the welding speed. Indeed the energy density ie being higher, the temperature rise in the stack is faster.
  • the first zone 27 of the upper face 14 of the first sheet 10 which is heated by the first heating source 26 is optimized from the point of view of thermal transfer. It is then of elliptical shape in accordance with FIG. 6, its major axis can, for example, be parallel to the path of the weld bead. This increases the heating efficiency of the area to be welded.
  • a single laser source emits a laser beam which feeds the optics 32 and 34.
  • the method thus described makes it possible to produce, by transparency, welding spots or beads without porosity from a stack of two sheets without play so that the sheets are in contact in the area to be welded. This eliminates the costly operations of preparing the sheets and facilitates their positioning relative to each other.

Abstract

The invention concerns a method for welding a stack of sheet metals comprising at least a top sheet metal (10) and a bottom sheet metal (12) one of which at least is coated with a metal coating. The invention is characterised in that it comprises the following successive steps: stacking tightly two sheet metals (10, 12); heating with a first heat source (26) directed on the outer surface of one of the sheet metals of the stack, a first zone (27) such that the temperature of each coated inner surface (16, 20) is higher than the evaporation temperature of the coating of said surface and such that the temperature of each sheet metal, in the proximity of the interface between the two sheet metals (10, 12) is less than the melting point thereof; then, after the vapours of the coating have been evacuated from a second zone included in the first zone, heating with a second source a third zone (42), at a temperature causing local fusion of each sheet metal.

Description

"Procédé et dispositif de soudage de tôles" "Method and device for welding sheets"
L'invention concerne un procédé et un dispositif de soudage d'un empilement de tôles revêtues.The invention relates to a method and a device for welding a stack of coated sheets.
L'invention concerne plus particulièrement un procédé de soudage d'un empilement de tôles comprenant au moins une tôle supérieure et une tôle inférieure superposées dont l'une au moins est revêtue, au moins sur sa face interne adjacente à l'autre tôle, par au moins un revêtement métallique ayant une température de vaporisation inférieure ou égale à la température de fusion de la tôle de l'empilement ayant la température de fusion la plus faible.The invention relates more particularly to a method of welding a stack of sheets comprising at least one upper sheet and one lower sheet superposed, at least one of which is coated, at least on its internal face adjacent to the other sheet, by at least one metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the lowest melting temperature.
L'invention concerne aussi un d ispositif de "soudage laser d'un empilement de tôles revêtues d'un revêtement métallique ayant une température de vaporisation inférieure ou égale à la température de fusion de la tôle de l'empilement ayant la température de fusion la plus faible.The invention also relates to a device for " laser welding of a stack of sheets coated with a metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the melting temperature 1a. weaker.
De tels empilements sont de plus en plus utilisés dans la lutte contre - la corrosion , notamment dans l'ind ustrie automobile. Le soudage d'un empilement de tôles présente donc des enjeux importants surtout lorsqu'il s'ag it de souder un empilement des tôles d'acier revêtues de zinc ou d'alliages de zinc.Such stacks are increasingly used in the fight against - corrosion, in particular in the automotive industry. Welding a stack of sheets therefore presents significant challenges, especially when it comes to welding a stack of steel sheets coated with zinc or zinc alloys.
Le soudage par laser a l'avantage de chauffer les matériaux très localement, et ainsi de ne causer que de faibles déformations du revêtement de zinc et de la tôle. Le soudage par laser est devenu une technique très utilisée pour souder des tôles revêtues. Plusieurs techniques peuvent être mises en œuvre .Laser welding has the advantage of heating the materials very locally, and thus only causing slight deformations of the zinc coating and of the sheet metal. Laser welding has become a widely used technique for welding coated sheets. Several techniques can be implemented.
L'une consiste à souder le bord de la tôle supérieure sur la tôle inférieure, c'est la technique dite de soudage à clin . Le laser doit chauffer la tranche de la tôle supérieure. Cette opération req uiert une g rande précision , cependant les tolérances des tôles sont importantes. I l est donc nécessaire de suivre les bords de la tôle supérieure. Un d ispositif détecte en permanence la position du bord de la tôle supérieure et oriente la source laser afin que son point de focalisation soit situé au bon end roit. Ce dispositif est très coûteux.One is to weld the edge of the upper sheet onto the lower sheet, this is the technique known as lap welding. The laser should heat the edge of the top sheet. This operation requires great precision, however the sheet tolerances are important. It is therefore necessary to follow the edges of the upper sheet. A device detects in permanently position the edge of the upper sheet and orient the laser source so that its focal point is located at the right end. This device is very expensive.
U ne autre techn iq ue consiste à chauffer la face supérieure de la tôle supérieure qui va transmettre, par conduction , la chaleur à la tôle inférieure jusqu'à ce que la zone fond ue s'étende de ladite face supérieure à la face inférieure de la tôle inférieure. C'est le soudage dit par transparence. Avec cette techniq ue, un problème apparaît dans le joint de soud ure. I l est du à la température de vaporisation du zincAnother technique consists in heating the upper face of the upper sheet which will transmit, by conduction, the heat to the lower sheet until the bottom zone extends from said upper face to the lower face of the bottom sheet. This is the so-called transparency welding. With this technique, a problem appears in the weld joint. This is due to the vaporization temperature of the zinc
(environ 900 °C) qui est inférieure à la température de fusion de l'acier (environ 1 500 ° C) . En conséq uence, lors de la soudure, il se produit une vaporisation du zinc qui est préjudiciable à la qualité de la soudure.(about 900 ° C) which is lower than the melting temperature of the steel (about 1500 ° C). Consequently, during the welding, a vaporization of the zinc takes place which is detrimental to the quality of the welding.
Des bu lles de vapeurs de zinc se forment, occasionnant des cratères à l'intérieur de la soudure, ce qui affecte l'esthétique et~surtout à la qualité de la soudure.Bu lles of zinc vapors are formed, causing craters inside the weld, which affects the aesthetics and ~ especially the quality of the weld.
En effet, la soudure étant poreuse sa résistance mécanique est plus faible et son etanchéité n'est pas assurée.In fact, since the weld is porous, its mechanical resistance is lower and its seal is not guaranteed.
De plus, le soudage provoque des projections de métal en fusion vers l'extérieu r des tôles. Ces projections ont deux effets.In addition, welding causes splashes of molten metal to the outside of the sheets. These projections have two effects.
D'une part, il faut positionner les optiques associées aux appareils lasers et qui sont nécessaires à la focalisation du faisceau sur les tôles souder à une distance minimum q ui est supérieure à la d istance maximum des projections de métal en fusion. Cette d istance minimum , q ui est de l'ord re de 200 à 300 mil limètres , est supérieure à la distance permettant une focalisation précise du faisceau su r les tôles à souder.On the one hand, it is necessary to position the optics associated with the laser devices and which are necessary for the focusing of the beam on the sheets to be welded at a minimum distance which is greater than the maximum distance from the projections of molten metal. This minimum distance, which is on the order of 200 to 300 milimeters, is greater than the distance allowing precise focusing of the beam on the sheets to be welded.
D'autre part, les projections de métal en fusion diminuent la qualité du soudage par manque de matière. Pour remédier à ces inconvénients, il a été proposé de ménager un jeu entre les tôles pour favoriser l'évacuation des vapeurs de zinc lors du soudage.On the other hand, splashes of molten metal reduce the quality of welding due to a lack of material. To overcome these drawbacks, it has been proposed to provide a clearance between the sheets to promote the evacuation of zinc vapors during welding.
A cet effet, la demande de brevet français n° 95.02772 propose de réaliser, avant le soudage, un emboutissage de la zone à souder.To this end, French patent application No. 95.02772 proposes to carry out, before welding, a stamping of the zone to be welded.
Le demande de brevet internationale WO-A1 -99/08829 propose de former des protubérances par chauffage local sur la zone à souder de la surface supérieure de la tôle inférieure. Après avoir mis en place la tôle supérieure, les deux tôles sont soudées par transparence.The international patent application WO-A1 -99/08829 proposes to form protuberances by local heating on the zone to be welded of the upper surface of the lower sheet. After having installed the upper sheet, the two sheets are welded by transparency.
Ces solutions ne sont pas satisfaisantes. En effet, elles sont compliq uées à mettre en œuvre. De plus, elles augmentent le temps de travail sur les tôles et nécessitent des opérations supplémentaires coûteuses.These solutions are not satisfactory. Indeed, they are complicated to implement. In addition, they increase the working time on the sheets and require costly additional operations.
Dans le but d'apporter une solution à ces problèmes, l'invention propose un procédé d u type décrit précédemment, caractérisé en ce q u'il comprend les étapes successives suivantes : - empilage sans jeu des deux tôles ;In order to provide a solution to these problems, the invention provides a method of the type described above, characterized in that it comprises the following successive steps: - stacking without play of the two sheets;
- chauffage par une première source de chaleur dirigée sur la face externe de l'une des tôles de l'empilement, d'une première zone, de façon que la température de chaq ue face interne revêtue soit supérieure ou égale à la température de vaporisation du revêtement de cette face et de façon que la température de chaque tôle, au voisinage de l'interface entre les deux tôles, soit inférieure à sa température de fusion ;- Heating by a first heat source directed on the external face of one of the sheets of the stack, of a first zone, so that the temperature of each coated internal face is greater than or equal to the vaporization temperature of the coating of this face and so that the temperature of each sheet, in the vicinity of the interface between the two sheets, is lower than its melting temperature;
- puis, après que les vapeurs du revêtement aient évacué une deuxième zone comprise dans la première zone, chauffage par une seconde source de chaleur d'une troisième zone , comprise dans la seconde zone, à une température permettant la fusion locale de chaque tôle jusqu'à ce q ue l'empilement de tôles soit soudé.- Then, after the coating vapors have evacuated a second zone included in the first zone, heating by a second heat source of a third zone, included in the second zone, at a temperature allowing the local melting of each sheet up to 'that the stack of sheets is welded.
Selon d'autres caractéristiques du procédé : - on provoque un mouvement relatif entre les deux sources de chaleur et l'empilement de tôles de façon que la troisième zone se déplace par rapport à l'empilement de tôles pour former un cordon de soudure ; - les deux sources de chaleu r sont reliées entre elles par des moyens, permettant de régler en permanence leurs positions relatives, selon la direction de soudage, en fonction de l'épaisseur des tôles, du revêtement et de la vitesse du mouvement relatif des sources de chaleur par rapport à l'empilement de tôles ;According to other characteristics of the process: - a relative movement is caused between the two heat sources and the stack of sheets so that the third zone moves relative to the stack of sheets to form a weld bead; - the two heat sources are connected to each other by means, making it possible to permanently adjust their relative positions, according to the direction of welding, as a function of the thickness of the sheets, of the coating and of the speed of the relative movement of the sources heat with respect to the stack of sheets;
- le revêtement est un alliage contenant du zinc ;- the coating is an alloy containing zinc;
- le revêtement est du zinc ;- the coating is zinc;
- la première source de chaleur est une source laser ;- The first heat source is a laser source;
- la seconde source de chaleur est une source laser ; - la première et la seconde source de chaleur font appel à u ne source laser unique alimentant chacune des deux sources.- the second heat source is a laser source; - The first and second heat sources use a single laser source supplying each of the two sources.
L'invention propose aussi un dispositif de soudage laser d'un empilement de tôles revêtues d'un revêtement métalliq ue ayant une température de vaporisation inférieu re ou égale à la températu re de fusion de la tôle de l'empilement ayant la température de fusion la plus faible, caractérisé en ce qu'il comporte deux sources de chaleur attelées, et en ce qu'il permet de souder par transparence l'empilement sans jeu de tôles revêtues.The invention also provides a device for laser welding of a stack of sheets coated with a metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the melting temperature the weakest, characterized in that it comprises two coupled heat sources, and in that it makes it possible to weld the stack by transparency without a set of coated sheets.
Selon une autre caractéristique du dispositif, les deux sources de chaleur font appel à une source laser unique alimentant chacune des deux sources.According to another characteristic of the device, the two heat sources use a single laser source supplying each of the two sources.
L'invention propose donc un procédé et un dispositif permettant de souder un empilage de tôles revêtues de zinc par une soudure qui présente une bonne tenue mécanique.The invention therefore provides a method and a device for welding a stack of zinc-coated sheets by a weld which has good mechanical strength.
D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description détaillée qui su it pour la compréhension de laquelle on se reportera aux dessins annexés dans lesquels :Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:
- la figure 1 représente une vue en coupe de deux tôles revêtues ; - la figure 2 représente la première étape d u procédé d'assemblage selon l'invention de deux tôles revêtues ;- Figure 1 shows a sectional view of two coated sheets; - Figure 2 shows the first step of u assembly process according to the invention of two coated sheets;
- la figure 3 représente le g radient de température dans une coupe selon la ligne 3-3 de la figure 2 de l'assemblage des deux tôles lors de la première étape du procédé selon l'invention ;- Figure 3 shows the temperature radient in a section along line 3-3 of Figure 2 of the assembly of the two sheets during the first step of the method according to the invention;
- la figure 4 représente la deuxième étape d u procédé d'assemblage selon l'invention des deux tôles revêtues ";- Figure 4 shows the second step of the assembly process according to the invention of the two coated sheets " ;
- la figure 5 représente la zone soudée dans une coupe selon la ligne 5-5 que la figure 4 de l'assemblage des deux tôles lors de la deuxième étape du procédé selon l'invention ;- Figure 5 shows the welded area in a section along line 5-5 as Figure 4 of the assembly of the two sheets during the second step of the method according to the invention;
- la figure 6 représente un dispositif selon l'invention , mis en œuvre pour souder des tôles revêtues.- Figure 6 shows a device according to the invention, implemented for welding coated sheets.
Dans la' description une orientation supérieure, inférieure est utilisée, à titre non limitatif, conformément à la fig ure 1 . On a représenté su r la fig ure 1 une p remière tôle 1 0 et une seconde tôle 1 2.In the ' description an upper, lower orientation is used, without limitation, in accordance with fig ure 1. There is shown on fig ure 1 a first sheet 1 0 and a second sheet 1 2.
La première tôle supérieure 1 0 comporte une face supérieure 14 et une face inférieure 16 qui est revêtue d'une couche de zinc 1 8. La seconde tôle inférieure 12 comporte une face supérieure 20 et une face inférieure 22. La face supérieure 20 est revêtue d'une couche de zinc 24.The first upper sheet 1 0 has an upper face 14 and a lower face 16 which is coated with a layer of zinc 1 8. The second lower sheet 12 has an upper face 20 and a lower face 22. The upper face 20 is coated a layer of zinc 24.
Les deux faces 16 et 20 revêtues de zinc sont dites galvanisées. Avantageusement, selon une variante non représentée, les deux faces de chaque tôle sont galvanisées.The two faces 16 and 20 coated with zinc are said to be galvanized. Advantageously, according to a variant not shown, the two faces of each sheet are galvanized.
L'épaisseu r des tôles 10 et 12 varie de 0,6 à 2 millimètres et l'épaisseu r du revêtement de zinc varie entre 8 et 12 micromètres dans le cas d'applications au domaine de la construction automobile.The thickness of the sheets 10 and 12 varies from 0.6 to 2 millimeters and the thickness of the zinc coating varies between 8 and 12 micrometers in the case of applications in the automotive construction field.
L'invention consiste à réaliser deux étapes successives de chauffage d'une zone de l'empilement des tôles 1 0 et 12. U n premier mode de réalisation met en œuvre une première source de chauffage 26 et une seconde source de chauffage 28 pour réaliser un point de soudu re sensiblement cylind rique.The invention consists in carrying out two successive stages of heating an area of the stack of sheets 1 0 and 12. A first embodiment implements a first heating source 26 and a second heating source 28 to produce a substantially cylindrical weld point.
En vue du soudage, les deux tôles 1 0 et 12 sont superposées sans jeu vertical de façon que les couches de zinc 18 et 24 soient en contact dans les zones à souder.For welding, the two sheets 1 0 and 12 are superimposed without vertical play so that the zinc layers 18 and 24 are in contact in the areas to be welded.
Une première étape est illustrée aux fig ures 2 et 3 met en œuvre la première source de chauffage 26.A first step is illustrated in fig ures 2 and 3 implements the first heating source 26.
Elle permet préchauffer par rayonnement d'un faisceau d'énerg ie 30 une première zone d'impact 27 de forme sensiblement circulaire de diamètre D 1 de la face supérieure 14 de la première tôle 1 0. Le transfert de chaleu r se fait par conduction rapide assurant ainsi une faible différence de températures entre celle de la zone 27 de la su rface supérieure 14 et celle à l'interface de soudage entre les faces 16 et 24. Le préchauffage se poursuit jusqu'à ce qu'une température supérieure à la température d'évaporation du zinc, c'est-à-d ire supérieure à 900 °C soit atteinte à l'interface des couches de zinc 1 8 et 24. La température des tôles 1 0 et 12 à proximité de l'interface reste, quant à elle, à une température inférieure à la température de fusion , en vue du soudage, q u i dans le cas de l'acier est supérieure à 1 500 °C .It allows preheating by radiation of an energy beam ie a first impact zone 27 of substantially circular shape of diameter D 1 of the upper face 14 of the first sheet 1 0. The heat transfer r is done by conduction rapid thus ensuring a slight temperature difference between that of the zone 27 of the upper surface 14 and that at the welding interface between the faces 16 and 24. Preheating continues until a temperature above the zinc evaporation temperature, that is to say greater than 900 ° C is reached at the interface of the zinc layers 1 8 and 24. The temperature of the sheets 1 0 and 12 near the interface remains , meanwhile, at a temperature below the melting temperature for welding, which in the case of steel is greater than 1500 ° C.
Cette première étape assure l'évacuation des vapeurs de zinc en dehors de la future zone de soudage.This first step ensures the evacuation of zinc vapors outside the future welding zone.
U n gradient de température existe dans l'assemblage des deux tôles 10 et 12. I l est représenté partiellement à la figure 3. Une température T1 correspond à la températu re de vaporisation du zinc et une température T2 correspond à une température inférieure à la température de fusion de l'acier.A temperature gradient exists in the assembly of the two sheets 10 and 12. It is partially represented in FIG. 3. A temperature T1 corresponds to the temperature of vaporization of the zinc and a temperature T2 corresponds to a temperature below the melting temperature of the steel.
Le zinc et la vapeur de zinc sont alors évacués d'une deuxième zone de diamètre D2 supérieure au diamètre du point de soud ure à réaliser u ltérieurement.The zinc and the zinc vapor are then evacuated from a second zone of diameter D2 greater than the diameter of the welding point to be produced at the inside.
Avantageusement, la première source de chauffage 26 est une source laser telle qu'une source dite YAG ou C02 ou une diode laser.Advantageously, the first heating source 26 is a laser source such as a so-called YAG or C0 2 source or a laser diode.
L'utilisation d'une diode laser est adaptée à cette première étape. En effet, elle permet de chauffer une zone 27 de 2 ou 3 mm de d iamètre, contrairement à d'autres sources lasers q ui focalisent en une zone de plus petite.The use of a laser diode is suitable for this first step. Indeed, it makes it possible to heat an area 27 of 2 or 3 mm in diameter, unlike other laser sources which focus on a smaller area.
Pou r cette première étape l'utilisation d'une source laser YAG est plus adaptée que l'utilisation d'une source laser C02. En effet, le coefficient d'absorption de l'acier varie en fonction de la long ueur d'onde d u faisceau incident. I l diminue lorsq ue la longueu r d'onde du rayonnement augmente. Le coefficient d'absorption de la tôle pour un rayonnement émis par la source laser YAG de 1 micromètre de longueur d'onde est de l'ord re de 20 à 30 % . La longueur d'onde d u rayonnement émis par la source C02 est de 1 0 micromètres soit dix fois supérieure à cel le du rayonnement émis par la source YAG, le coefficient d'absorption de la tôle étant alors de l'ordre de 10 à 1 5% .For this first step the use of a YAG laser source is more suitable than the use of a C0 2 laser source. In fact, the absorption coefficient of the steel varies as a function of the wavelength of the incident beam. It decreases when the wavelength of the radiation increases. The absorption coefficient of the sheet for radiation emitted by the YAG laser source of 1 micrometer in wavelength is around 20 to 30%. The wavelength of the radiation emitted by the source C0 2 is 10 micrometers or ten times greater than that of the radiation emitted by the source YAG, the absorption coefficient of the sheet then being of the order of 10 to 1 5%.
Lorsque la sou rce de chauffage 26 est une première sou rce laser elle émet à travers une optiq ue 32 un faisceau laser qui est fortement absorbé par la première tôle 1 0.When the heating source 26 is a first laser source, it emits through an optic 32 a laser beam which is strongly absorbed by the first sheet 1 0.
U ne seconde étape illustrée aux figu res 4 et 5 est mise en œuvre après u n temps déterminé. Ce temps déterminé doit être suffisant pou r permettre le refroid issement et la condensation des vapeurs de zinc au-delà de la deuxième zone de diamètre D2, conformément à la figure 5 , supérieure au d iamètre d u point de soudure ultérieur. De plus, la maîtrise de la pénétration d u soudage lors de la deuxième étape de chauffage s'obtient à partir d'une valeur constante de températu re résiduelle de la première étape dans l'assemblage des deux tôles 10 et 12.A second step illustrated in FIGS. 4 and 5 is implemented after a determined time. This determined time must be sufficient to allow cooling and condensation of the zinc vapors beyond the second zone of diameter D2, in accordance with FIG. 5, greater than the diameter of the subsequent welding point. In addition, control of the welding penetration during the second heating step is obtained from a constant value of residual temperature of the first stage in the assembly of the two sheets 10 and 12.
La seconde source de chauffage 28 permet par exemple le soudage à haute densité d'énerg ie selon u ne techn ique connue de l'état de la technique dite soudage en "key-hole".The second heating source 28 allows for example the welding with high energy density ie according to a technique known from the state of the art called "key-hole" welding.
Conformément à la figure 5, u ne zone d'impact 40 d u faisceau d'énergie 36 sur la face supérieure 14 de la première tôle 10 a un diamètre D4 inférieur au diamètre D 1 de la première zone 27 de chauffée lors de la première étape. Le transfert par conduction thermique permet de fond re les deux tôles 10 et 12 dans une troisième zone 42. Cette troisième zone 42 a un diamètre D3 au niveau de l'interface entre la première tôle 10 et la seconde tôle 12 qui est inférieur au diamètre D2 correspondant à la zone dans laquelle le zinc a été évacué lors de la première étape.In accordance with FIG. 5, an impact zone 40 of the energy beam 36 on the upper face 14 of the first sheet 10 has a diameter D4 less than the diameter D 1 of the first zone 27 heated during the first step . The transfer by thermal conduction allows the two sheets 10 and 12 to be melted in a third zone 42. This third zone 42 has a diameter D3 at the interface between the first sheet 10 and the second sheet 12 which is less than the diameter D2 corresponding to the zone in which the zinc was removed during the first stage.
Le zinc ayant été évacué de la troisième zone 42 aucune bulle de gaz provenant de sa vaporisation ne se retrouve dans l'acier en fusion.The zinc having been evacuated from the third zone 42 no gas bubble coming from its vaporization is found in the molten steel.
De ce fait, il ne se produit aucune projection d'acier en fusion vers l'extérieur de la zone soudée. La source de chauffage 28 n'étant pas exposée aux projections , il est possible de la rapprocher de la face 14 de manière à obtenir une distance focale courte, c'est-à-dire de l'ord re de 1 00 mm. Cela permet d'augmenter la densité d'énerg ie de la source 28 et par conséquent de réduire la puissance et donc la consommation d'énergie de la source de chauffage 28 pour un chauffage identique.As a result, there is no projection of molten steel to the outside of the welded area. As the heating source 28 is not exposed to projections, it is possible to bring it closer to the face 14 so as to obtain a short focal distance, that is to say of the order of 1 00 mm. This makes it possible to increase the energy density ie of the source 28 and consequently to reduce the power and therefore the energy consumption of the heating source 28 for identical heating.
Après refroid issement, la troisième zone 42 est u ne soudure exempte de toute porosité et sa tenue mécanique est maximale.After cooling, the third zone 42 is a weld free from any porosity and its mechanical strength is maximum.
Avantageusement, la seconde source de chauffage 28 est une source laser YAG ou C02 ayant une puissance comprise entre 2 et 6 kW suivant les paramètres de soudage. L'utilisation de l'une ou l'autre des sources lasers est équivalente. En effet, la mise en œuvre du soudage d it en key- hole permet de s'affranchir d u coefficient d'absorption des tôles. Les rendements énergétiques des deux sou rces lasers sont similaires. Si la seconde source de chauffage 28 est une seconde sou rce laser, elle émet à travers une optique 34 un faisceau 36 à plus haute densité d'énerg ie que la première source de chauffage 26.Advantageously, the second heating source 28 is a YAG or C02 laser source having a power of between 2 and 6 kW depending on the welding parameters. The use of one or other of the laser sources is equivalent. Indeed, the implementation of it welding in keyhole overcomes the absorption coefficient of the sheets. The energy yields of the two laser sources are similar. If the second heating source 28 is a second laser source, it emits through an optic 34 a beam 36 with a higher energy density than the first heating source 26.
Avantageusement, les sources de chauffage 26 et 28 sont une source de chauffage unique dont on fait varier la puissance, la distance focale et/ou le d iamètre de la zone chauffée.Advantageously, the heating sources 26 and 28 are a single heating source, the power, the focal distance and / or the diameter of the heated area being varied.
Selon un deuxième mode de réalisation illustré à la figu re 6 on met en œuvre la première source de chauffage 26 et la seconde sou rce de chauffage 28 pour réaliser un cordon de soudure 44.According to a second embodiment illustrated in FIG. 6, the first heating source 26 and the second heating source 28 are used to produce a weld bead 44.
Les deux sources de chauffage 26 et 28 sont fixées à un même bras robotisé 46 q ui permet de suivre précisément la forme du cordon de soudure 44 déterminé. Les puissances des deux sources 26 et 28 sont rég lées de manière à réaliser les deux étapes précédentes successivement en une seule passe.The two heating sources 26 and 28 are fixed to the same robotic arm 46 which enables the shape of the determined weld bead 44 to be precisely monitored. The powers of the two sources 26 and 28 are adjusted so as to carry out the two preceding stages successively in a single pass.
La seconde sou rce de chauffage 28 est fixée à une coulisse 48 asservie. Cette dernière permet de rég ler la distance entre la première 26 et la seconde 28 source de chauffage de manière à maintenir les mêmes paramètres de mise en œuvre d u procédé en prenant en compte les variations de courbure de la trajectoire du cordon de soud ure 44 et/ou de l'épaisseur des deux tôles 1 0 et 12. Comme la maîtrise de la pénétration du soudage lors de la deuxième étape s'obtient à partir d'une valeu r constante de température résiduelle dans l'empilement des tôles 1 0 et 12, la valeur de température résiduelle est maintenue par rég lage de la distance entre les sources pour compenser les variations de vitesse et les différences d'épaisseur.The second heating source 28 is fixed to a slave slide 48. The latter makes it possible to adjust the distance between the first 26 and the second 28 heating source so as to maintain the same parameters for implementing the method by taking into account the variations in curvature of the trajectory of the weld bead 44 and / or the thickness of the two sheets 1 0 and 12. As the control of the penetration of welding during the second step is obtained from a constant value of residual temperature in the stack of sheets 1 0 and 12, the residual temperature value is maintained by setting the distance between the sources to compensate for variations in speed and differences in thickness.
Lorsque la vitesse de soudage augmente, il est nécessaire, d'augmenter la distance qui sépare les deux sources de chaleur 26 et 28 , pour que le temps écoulé entre le chauffage d'une zone déterminée par la première source de chaleur 26 et le chauffage de cette même zone par la seconde source de chaleur 28 reste constant.When the welding speed increases, it is necessary to increase the distance between the two heat sources 26 and 28, so that the time elapsed between the heating of an area determined by the first heat source 26 and the heating of this same area by the second heat source 28 remains constant.
De même, si l'épaisseur de l'empilement des tôles 10 et 12 varie, il faut modifier la vitesse de soudage et/ou la distance entre les deux sources de chauffage.Likewise, if the thickness of the stack of sheets 10 and 12 varies, the welding speed and / or the distance between the two heating sources must be modified.
La mise en œuvre de ce deuxième mode de réalisation permet, comme dans le premier, d'évacuer le zinc de la troisième zone 42 soudée. L'absence de projections et donc la possibilité de rapprochement des deux sources de chauffage permet d'aug menter la vitesse de soudage. En effet la densité d'énerg ie étant plus importante, l'élévation de température dans l'empilement est plus rapide. Avantageusement, la première zone 27 de la face supérieure 14 de la première tôle 10 qui est chauffée par la première source de chauffage 26 est optimisée d u point de vue d u transfert thermique. Elle est alors de forme elliptique conformément à la figure 6 , son grand axe peut, par exemple être parallèle à la trajectoire du cordon de soudure. Cela permet d'augmenter l'efficacité du chauffage de la zone à souder.The implementation of this second embodiment allows, as in the first, to remove the zinc from the third welded zone 42. The absence of projections and therefore the possibility of bringing the two heating sources closer together makes it possible to increase the welding speed. Indeed the energy density ie being higher, the temperature rise in the stack is faster. Advantageously, the first zone 27 of the upper face 14 of the first sheet 10 which is heated by the first heating source 26 is optimized from the point of view of thermal transfer. It is then of elliptical shape in accordance with FIG. 6, its major axis can, for example, be parallel to the path of the weld bead. This increases the heating efficiency of the area to be welded.
Avantageusement, une source laser unique émet un faisceau laser qu i alimente les optiques 32 et 34. Le procédé ainsi décrit permet de réaliser, par transparence des points ou des cordons de soudu re sans porosité à partir d'un empilement de deux tôles sans jeu de façon que les tôles soient en contact dans la zone à souder. Cela supprime les opérations coûteuses de préparation des tôles et facilite leur positionnement l'une par rapport à l'autre. Advantageously, a single laser source emits a laser beam which feeds the optics 32 and 34. The method thus described makes it possible to produce, by transparency, welding spots or beads without porosity from a stack of two sheets without play so that the sheets are in contact in the area to be welded. This eliminates the costly operations of preparing the sheets and facilitates their positioning relative to each other.

Claims

REVEND I CATIONS RESELL I CATIONS
1 . P rocédé de soudage d'un empilement de tôles comprenant au moins une tôle supérieure ( 1 0) et u ne tôle inférieure ( 12) superposées dont l'une au moins est revêtue, au moins sur sa face interne adjacente à l'autre tôle , par au moins un revêtement métallique ayant une température de vaporisation inférieure ou égale à la température de fusion de la tôle de l'empilement ayant la température de fusion la plus faible, du type qui comprend les étapes successives suivantes :1. Process for welding a stack of sheets comprising at least one upper sheet (1 0) and one lower sheet (12) superposed, at least one of which is coated, at least on its internal face adjacent to the other sheet , by at least one metallic coating having a vaporization temperature lower than or equal to the melting temperature of the sheet of the stack having the lowest melting temperature, of the type which comprises the following successive steps:
- empilage sans jeu des deux tôles ( 1 0 , 12) ;- stacking without play of the two sheets (1 0, 12);
- chauffage par une première' source de chaleur (26) dirigée sur la face externe de l'une des tôles de l'empilement, d'une première zone (27, D 1 ) , de façon que la température de chaq ue face interne (16 , 20) revêtue soit supérieure ou égale à la température de vaporisation du revêtement de cette face et de façon que la température de chaque tôle, au voisinage de l'interface entre les deux tôles, soit inférieure à sa température de fusion ; - puis , après que les vapeurs du revêtement aient évacué une deuxième zone (D2) comprise dans la première zone, chauffage par une seconde source de chaleur d'une troisième zone (42, D3) , comprise dans la deuxième zone (D2) , à une températu re permettant la fusion locale de chaque tôle jusqu'à ce que l'empilement de tôles soit soudé, caractérisé en ce que les deux sources de chaleur sont reliées entre elles par des moyens (48) , permettant de régler en permanence leurs positions relatives, selon la direction de soudage, en fonction de l'épaisseur des tôles, du revêtement et de la vitesse du mouvement relatif des sources de chaleu r (26) , (28) par rapport à l'empilement de tôles ( 10, 12) .- heating a first source of heat (26) directed onto the outer one of the sheets of the stack face, a first area (27, D 1) so that the temperature of CHAQ ue inner face (16, 20) coated is greater than or equal to the vaporization temperature of the coating of this face and so that the temperature of each sheet, in the vicinity of the interface between the two sheets, is lower than its melting temperature; - then, after the coating vapors have evacuated a second zone (D2) included in the first zone, heating by a second heat source of a third zone (42, D3), included in the second zone (D2), at a temperature allowing local melting of each sheet until the stack of sheets is welded, characterized in that the two heat sources are connected to each other by means (48), making it possible to continuously adjust their relative positions, according to the direction of welding, as a function of the thickness of the sheets, of the coating and of the speed of the relative movement of the heat sources r (26), (28) with respect to the stack of sheets (10, 12).
2. Procédé selon la revendication 1 , caractérisé en ce l'on provoque un mouvement relatif entre les deux sources de chaleu r (26 , 28) et l'empilement de tôles de façon q ue la troisième zone (42) se déplace par rapport à l'empilement de tôles pour former un cordon de soudure (44).2. Method according to claim 1, characterized in that it causes a relative movement between the two sources of heat r (26, 28) and the stack of sheets so q ue the third zone (42) moves relative to the stack of sheets to form a weld bead (44).
3. Procédé selon l'une q uelconque des revend ications 1 ou 2, caractérisé en ce que le revêtement est un alliage contenant du zinc.3. Method according to one q uelconque of resells ications 1 or 2, characterized in that the coating is an alloy containing zinc.
4. Procédé selon l'une quelconque des revendications 1 ou 2, caractérisé en ce que le revêtement est du zinc.4. Method according to any one of claims 1 or 2, characterized in that the coating is zinc.
5. Procédé selon une quelconque des revendications précédentes, caractérisé en ce que la première source de chaleur (26) est une source laser.5. Method according to any one of the preceding claims, characterized in that the first heat source (26) is a laser source.
6. Procédé selon une quelconq ue des revendications précédentes , caractérisé en ce que la seconde source de chaleur (28) est une source laser.6. Method according to any one of the preceding claims, characterized in that the second heat source (28) is a laser source.
7. Procédé selon les revend ications 5 et 6, caractérisé en ce q ue la première et la seconde source de chaleur (26 , 28) font appel à une source laser unique alimentant chacune des deux sources.7. Method according to sells ications 5 and 6, characterized in that the first and second heat sources (26, 28) use a single laser source supplying each of the two sources.
8. Dispositif de soudage laser d'un empilement de tôles ( 1 0, 12) revêtues d'un revêtement métallique ayant une température de vaporisation inférieure ou égale à la température de fusion de la tôle de l'empilement ayant la température de fusion la plus faible, caractérisé en ce qu'il comporte deux sources de chaleur (26 , 28) attelées et en ce qu'il permet de souder par transparence sans jeu l'empilement de tôles revêtues selon la revend ication 1 .8. Device for laser welding a stack of sheets (1 0, 12) coated with a metallic coating having a vaporization temperature less than or equal to the melting temperature of the sheet of the stack having the melting temperature 1a. lower, characterized in that it comprises two heat sources (26, 28) coupled and in that it makes it possible to weld by transparency without play the stack of coated sheets according to resell ication 1.
9. Dispositif selon la revendication précédente, caractérisé en ce que les deux sources de chaleur (26, 28) font appel à une source laser unique alimentant chacune des deux sources (26 , 28) . 9. Device according to the preceding claim, characterized in that the two heat sources (26, 28) use a single laser source supplying each of the two sources (26, 28).
PCT/FR2000/002419 1999-09-03 2000-09-01 Method and device for welding sheet metal WO2001017722A1 (en)

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FR2830477A1 (en) * 2001-10-09 2003-04-11 Usinor Overlapping welding of coated metal sheets e.g., steel strip coated with zinc involves splitting high density energy beam to produce two molten metal baths and injecting neutral gas jet onto second bath to form sink at its surface
DE10203010A1 (en) * 2002-01-26 2003-08-14 Thyssenkrupp Stahl Ag Method and device for producing a weld or solder seam
DE10315976A1 (en) * 2003-04-08 2004-10-21 Volkswagen Ag To prepare coated metal sheets for soldering/welding, for vehicle bodywork parts, the surface coating is removed by a laser beam at the joint surface zones
WO2005107996A2 (en) * 2004-05-10 2005-11-17 Fronius International Gmbh Laser hybrid welding method and laser hybrid welding torch using a zinc and/or carbon and/or aluminum-containing rod
JP2017052006A (en) * 2015-09-10 2017-03-16 新日鐵住金株式会社 Lap joint coupler and method for manufacturing same
WO2018010132A1 (en) * 2016-07-14 2018-01-18 GM Global Technology Operations LLC Multi-beam laser spot welding of coated steels
CN110539064A (en) * 2019-09-06 2019-12-06 鞍钢股份有限公司 vacuum electron beam welding method for titanium steel composite blank by adopting edge strip assembly
US11077522B2 (en) 2016-01-18 2021-08-03 GM Global Technology Operations LLC Method of laser spot welding coated steels

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FR2823458B1 (en) * 2001-04-11 2003-08-22 Renault IMPROVED DEVICE AND METHOD OF LASER WELDING SAID BI-PASS
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DE102011004116A1 (en) * 2011-02-15 2012-08-16 Robert Bosch Gmbh Method and device for welding components by means of a laser beam
WO2017173650A1 (en) 2016-04-08 2017-10-12 GM Global Technology Operations LLC Method for laser welding steel workpieces

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Cited By (14)

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FR2830477A1 (en) * 2001-10-09 2003-04-11 Usinor Overlapping welding of coated metal sheets e.g., steel strip coated with zinc involves splitting high density energy beam to produce two molten metal baths and injecting neutral gas jet onto second bath to form sink at its surface
WO2003031111A1 (en) * 2001-10-09 2003-04-17 Usinor Method and device for overlapping welding of two coated metal sheets with a beam of high energy density
US6914213B2 (en) 2001-10-09 2005-07-05 Usinor Method and device for overlapping welding of two coated metal sheets with a beam of high energy density
DE10203010A1 (en) * 2002-01-26 2003-08-14 Thyssenkrupp Stahl Ag Method and device for producing a weld or solder seam
DE10315976A1 (en) * 2003-04-08 2004-10-21 Volkswagen Ag To prepare coated metal sheets for soldering/welding, for vehicle bodywork parts, the surface coating is removed by a laser beam at the joint surface zones
WO2005107996A3 (en) * 2004-05-10 2006-02-16 Fronius Int Gmbh Laser hybrid welding method and laser hybrid welding torch using a zinc and/or carbon and/or aluminum-containing rod
WO2005107996A2 (en) * 2004-05-10 2005-11-17 Fronius International Gmbh Laser hybrid welding method and laser hybrid welding torch using a zinc and/or carbon and/or aluminum-containing rod
EP1800790A1 (en) * 2004-05-10 2007-06-27 Fronius International GmbH Process of starting a hybrid laser welding process for welding of coated metal sheets with a backward and forward motion of the laser beam for evaporating the coating
US8471173B2 (en) 2004-05-10 2013-06-25 Fronius International Gmbh Laser hybrid welding method and laser hybrid welding torch using a zinc and/or carbon and/or aluminum-containing rod
JP2017052006A (en) * 2015-09-10 2017-03-16 新日鐵住金株式会社 Lap joint coupler and method for manufacturing same
US11077522B2 (en) 2016-01-18 2021-08-03 GM Global Technology Operations LLC Method of laser spot welding coated steels
WO2018010132A1 (en) * 2016-07-14 2018-01-18 GM Global Technology Operations LLC Multi-beam laser spot welding of coated steels
US11148226B2 (en) 2016-07-14 2021-10-19 GM Global Technology Operations LLC Multi-beam laser spot welding of coated steels
CN110539064A (en) * 2019-09-06 2019-12-06 鞍钢股份有限公司 vacuum electron beam welding method for titanium steel composite blank by adopting edge strip assembly

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