EP1474262A2 - Method of welding motor vehicle elements, in particular tailored blanks - Google Patents
Method of welding motor vehicle elements, in particular tailored blanksInfo
- Publication number
- EP1474262A2 EP1474262A2 EP03709888A EP03709888A EP1474262A2 EP 1474262 A2 EP1474262 A2 EP 1474262A2 EP 03709888 A EP03709888 A EP 03709888A EP 03709888 A EP03709888 A EP 03709888A EP 1474262 A2 EP1474262 A2 EP 1474262A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- elements
- welding
- wire
- assembled
- parts
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
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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
- B23K9/00—Arc welding or cutting
- B23K9/06—Arrangements or circuits for starting the arc, e.g. by generating ignition voltage, or for stabilising the arc
- B23K9/073—Stabilising the arc
- B23K9/0735—Stabilising of the arc length
Definitions
- the present invention relates to the application of a MIG / MAG (Metal Inert Gas / Metal Active Gas) process, of welding or soldering, to the electric arc of thin sheets coated or not, in particular electro sheets.
- MIG / MAG Metal Inert Gas / Metal Active Gas
- galvanized or galvanized used mainly in the sector. of the automotive industry, mainly to assemble by welding or soldering different components of the structure of a motor vehicle, such as body elements, doors, as well as floor joints, including suspension elements .
- HLE and THLE steels high or very high elastic limit
- variable thicknesses ranging from 0.6 to 4 mm, and usually from 0.6 to 2 mm.
- the low-energy welding short circuit MIG process is more particularly suitable for welding thin layers but generates projections at ignition and in steady state.
- the MIG process with pulsed regime allows a very good control of the transfer with absence of projections but its higher welding energy, even at low wire speed, leads to greater penetrations therefore an opposite effect to that sought.
- it hardly accommodates degraded or approximate preparations, such as a clearance or spacing between the sheets to be welded of the order of the thickness of the thinnest sheet.
- the detachment of the drop of liquid metal towards the molten bath is ensured by a large part of the electrical energy transmitted to the wire and restored via the arc to the base metal.
- zinc which is the main coating for this type of sheet, is characterized by a melting point of around 402 ° C and a boiling point of zinc of around 906 ° C which are very much lower than that of the base metal, that is to say the sheets to be joined, and the filler metal, that is to say the fusible wire. Therefore, it is vaporized during the welding operation by a direct action of the electric arc but also by simple thermal conduction in front and on the edges of the weld pool.
- the zinc vapors disturb the gas protection and the transfer, and thus cause porosities in the bead but also instabilities and projections.
- This phenomenon is all the more sensitive when the thickness of the coating is large compared to the welded thickness and when the joint configurations, in particular of the lap type which are mainly used in applications in the automotive sector, present to the interface two trapped contiguous zinc layers which worsen the degassing conditions.
- the acceptance tolerances for porosities are well defined with regard to non-emerging porosities, the tolerance is generally zero for the porousities vis-à-vis the appearance criteria, c 'is to say the aesthetics, and subsequent painting conditions on vehicle production lines.
- soldering also has the advantage of a significantly reduced energy input since only a fusion of the wire is necessary and not of the sheets, and the quantity of zinc vaporized is therefore greatly reduced compared to conventional welding.
- all these advantages are reduced by the cost of the filler metal, that is to say the soldering wire to be used.
- the problem which arises specifically in welding elements dedicated to the automotive construction sector is that, as explained above, the short-circuit and pulsed welding methods do not make it possible to simultaneously meet the requirements in terms control of penetrations and deformations, by the excess energy returned to the sheet, or control of projections by the significant energy to be used to obtain the detachment of the drops of molten metal, while the welding process brazing leads to advantages in terms of welding quality and comfort but at the expense of a much higher overall cost of the process due to the use of fusible brazing wire made of rather expensive special alloys.
- the object of the invention is then to solve these problems of the prior art by proposing an industrial solution perfectly suited to the motor vehicle manufacturing sector, making it possible to obtain an absence of projections, an implementation of minimal energy. , higher welding speeds, reduced penetrations and deformations of the sheets.
- the solution of the invention is then an electric arc welding process using a fusible wire subjected to a cyclic mechanical movement, alternately in approach and then away from the parts to be welded, so as to create a short circuit between the end of the fusible wire and at least one of the parts to be assembled and thus to deposit molten metal to progressively produce a solder joint between said parts, characterized in that the parts to be assembled are constituent elements of a motor vehicle.
- the method of the invention may include one or more of the following technical characteristics:
- the cyclic mechanical movement in approach and away from the wire relative to the weld pool is controlled in frequency, in speeds, in high time of arc stabilization and in low time of contact with the weld pool by at least one microprocessor in synchronization with a current source used to generate the arc and the welding current.
- the elements to be welded have a thickness of less than 5 mm, preferably between 0.5 and 2 mm.
- the elements to be welded have a zinc coating on at least one of their faces.
- the metal parts are made of high and very high yield strength unalloyed carbon steel.
- At least a part of the metal parts to be assembled are made of aluminum or an aluminum alloy and chosen from boxes or body parts, in particular sheet / extruded or extruded / extruded junctions; openings, such as doors or hoods; ground connection elements, such as suspension arms, cradles, sleepers and rims.
- At least part of the metal parts to be assembled are made of austenitic or ferritic stainless steels, in particular the exhaust pipes or parts of the exhaust pipes.
- the elements to be assembled chosen from the group formed by the body, the underbody, the butted sides, the side members, the wheel arches, the under-seat crosspieces, the foot reinforcements, the board crosspieces edge, the front crossmembers, the shock absorbers and the engine cradle.
- the intensity of the current is between 30 A and 250 A.
- the filler metal is in the form of wire with a diameter between 1.2 and 3.2 mm or strip of section between 0.5 x 4 and 0.6x 5 mm 2 .
- the filler wire is made of unalloyed or low alloyed steel, austenitic or ferritic stainless steel, nickel or nickel alloys, copper or copper alloys, aluminum or aluminum alloys.
- the weld beads to be produced have a length of between 5 and 100 mm, preferably between 10 mm and 70 mm.
- the invention also relates to a method of manufacturing a motor vehicle formed from several elements assembled by a welding method according to the invention, preferably implemented by a welding robot, for example on a production line for motor vehicles.
- the principle of the invention is based on the fact of forcing a short circuit to occur between the fusible wire and the sheets to be assembled by means of a "mechanical" descent of the wire in the direction of the sheets to be welded so as to deposit the drop of molten metal in the melt, then carry out a subsequent mechanical removal of the wire after depositing the metal drop.
- This wire descent and ascent cycle must be controlled in frequency, speed, high time and low time by one or more microprocessors in synchronization with the current source.
- the electrical energy delivered is strictly intended for melting the wire. It is therefore reduced by a factor of 2 to 3 compared to that usually applied in a conventional MIG process.
- the invention is particularly suitable for assembling the body of the vehicle "in white" (sheets not pre-painted or painted) from the following constituent elements: rocker panels, planed sidewalls, hydroformed or reconstituted side rails, passage of wheels, seat crossmembers, middle leg reinforcements, dashboard crossmembers, front crossmembers, side members and shock absorbers (hydro-formed or reconstituted, and engine cradle.
- the range of thicknesses of these stamped or hydroformed components that can be thus welded is from 0.6 to 2 mm.
- These vehicle components are generally coated on both sides by electrogalvanizing or galvanizing.
- the final preparations in terms of play and misalignment, will therefore accumulate all of the elementary tolerances to reach values requiring either modification of the existing welding procedure, in particular a "sweep", that is to say a welding with transverse oscillation of the torch relative to the joint plane, with reduction of the welding speed for example, that is the adoption of a more flexible process, for example a braze-brazing process instead of welding.
- the cords to be produced are typically discontinuous cords of variable length between 15 and 60 mm which are 'mechanically effective' over their entire length, that is to say dimensioned with respect to fatigue resistance but also of frontal or even side crash tests. It is therefore essential that the starts and end of the cords are as well controlled and without projections.
- a current generator of the 480 TRS type from LA SOUDURE AUTOGENE FRAN ⁇ AISE a MIG welding torch with wire feed device, a wire feeder, a device making it possible to impart a reciprocating movement back and forth over the wire, that is to say in approaching then in moving away.
- the installation making it possible to implement the invention consists of a reeling module comprising a drive system for pressure rollers coupled to an electric motor with or without an intermediate reducer.
- the wire feed regulation can be ensured by a tacho dynamo system for example or by another suitable regulation system.
- the installation also includes a wire supply bundle formed by a concentric sheath in which the fusible wire, the welding gas and, as the case may be, the torch cooling circuit pass; a reeling module located as close as possible to the torch, which may include one or more stepping type motors for driving the fusible wire at the desired average speed and ensuring the downward and upward movement necessary for the operation of the process; a welding generator as described above or the like; a microprocessor control module for controlling the speed and movement of the wire, as well as the intensity delivered by the generator, in particular the shape of the current wave.
- the gas protection will be made for example with a gas of the gas mixture type Ar + C0 2 or Ar + C0 2 +0 2 for the welding of unalloyed carbon steels or weakly alloyed, or of the Ar + H 2 + C0 2 mixture type for the soldering of these same materials, or of the Ar + H2 + C0 2 or Ar + He + C0 2 type mixture for austenitic and ferritic stainless steels, as well as for nickel and its alloys, or of the argon type or mixture Ar + He, Ar + 02 or Ar + He + 0 2 for
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Arc Welding In General (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
Abstract
Description
Procédé de soudage d'éléments de véhicules automobilies, en particulier de flancs raboutés Method for welding parts of motor vehicles, in particular butted sides
La présente invention porte sur l'application d'un procédé MIG/MAG (Métal Inert Gas / Métal Active Gas), de soudage ou soudo-brasage, à l'arc électrique de tôles fines revêtues ou non, en particulier des tôles électro- zinguées ou galvanisées, utilisées principalement dans le secteur. de l'industrie de construction automobile, principalement pour assembler par soudage ou soudo-brasage différents éléments constitutifs de la structure d'un véhicule automobile, tels des éléments de la caisse, des ouvrants, ainsi que des jonctions sol, notamment des éléments de suspension.The present invention relates to the application of a MIG / MAG (Metal Inert Gas / Metal Active Gas) process, of welding or soldering, to the electric arc of thin sheets coated or not, in particular electro sheets. galvanized or galvanized, used mainly in the sector. of the automotive industry, mainly to assemble by welding or soldering different components of the structure of a motor vehicle, such as body elements, doors, as well as floor joints, including suspension elements .
Le soudage des éléments de véhicules comme les caisses met en œuvre des aciers HLE et THLE (haute ou très haute limite élastique) d'épaisseurs variables allant de 0,6 à 4 mm, et habituellement de 0,6 à 2 mm. De telles jonctions qui étaient réalisées initialement par soudage par résistance sont maintenant, pour des raisons d'accessibilité et de coûts des robots correspondants, réalisées par soudage à l'arc, essentiellement par procédé MIG à régime par court-circuit (short arc) ou puisé.The welding of vehicle elements such as bodies uses HLE and THLE steels (high or very high elastic limit) of variable thicknesses ranging from 0.6 to 4 mm, and usually from 0.6 to 2 mm. Such junctions which were initially carried out by resistance welding are now, for reasons of accessibility and cost of the corresponding robots, produced by arc welding, essentially by MIG process with short-circuit regime (short arc) or drawn.
Le procédé MIG à régime par court-circuit à faible énergie de soudage est plus particulièrement adapté au soudage des fines épaisseurs mais génère des projections à l'amorçage et en régime établi.The low-energy welding short circuit MIG process is more particularly suitable for welding thin layers but generates projections at ignition and in steady state.
Le procédé MIG à régime puisé, de par son pilotage, permet une très bonne maîtrise du transfert avec absence de projections mais son énergie de soudage plus élevée, même à faible vitesse fil, entraîne des pénétrations plus importantes donc un effet inverse à celui recherché. De plus, il s'accommode difficilement de préparations dégradées ou approximatives, tel un jeu ou espacement entre les tôles à souder de l'ordre de l'épaisseur de la tôle la plus fine.The MIG process with pulsed regime, by its piloting, allows a very good control of the transfer with absence of projections but its higher welding energy, even at low wire speed, leads to greater penetrations therefore an opposite effect to that sought. In addition, it hardly accommodates degraded or approximate preparations, such as a clearance or spacing between the sheets to be welded of the order of the thickness of the thinnest sheet.
Pour ces deux procédés, le détachement de la goutte de métal liquide vers le bain de fusion est assuré par une partie importante de l'énergie électrique transmise au fil et restituée via l'arc au métal de base.For these two methods, the detachment of the drop of liquid metal towards the molten bath is ensured by a large part of the electrical energy transmitted to the wire and restored via the arc to the base metal.
Cette excédant d'énergie va donc occasionner des pénétrations difficilement maîtrisables et/ou des projections directement liées à la stabilité du transfert de métal. On a tenté de résoudre ce problème via une substitution du soudage par du soudo-brasage en utilisant des métaux d'apport cuivreux, tels que des alliages CuAI ou CuSi à bas point de fusion et, dans tous les cas, très inférieur à la température de fusion du métal de base. De cette manière, on diminue l'énergie restituée à la tôle et donc les pénétrations et les déformations.This excess of energy will therefore cause penetrations that are difficult to control and / or projections directly linked to the stability of the metal transfer. An attempt has been made to solve this problem by substituting welding by brazing using copper filler metals, such as CuAI or CuSi alloys with low melting point and, in all cases, much lower than the temperature. base metal. In this way, the energy returned to the sheet is reduced and therefore the penetrations and deformations.
Ce procédé s'accommode bien de préparations industrielles avec jeu inter-tôles mais, en revanche, le coût du métal d'apport pénalise notablement la généralisation de son application dans le domaine industriel, en particulier dans le secteur de la construction de véhicules automobiles.This process is well suited to industrial preparations with inter-sheet play, but, on the other hand, the cost of the filler metal significantly penalizes the generalization of its application in the industrial field, in particular in the motor vehicle construction sector.
Par ailleurs, la réussite du soudage est également liée au potentiel du procédé à maîtriser le problème du dégazage et de la vaporisation du zinc, dans le cas du soudage de tôles revêtues par une couche de zinc.Furthermore, the success of welding is also linked to the potential of the process to overcome the problem of degassing and vaporization of zinc, in the case of welding of sheets coated with a layer of zinc.
En effet, d'une manière générale, le zinc qui constitue le principal du revêtement de ce type de tôles, se caractérise par un point de fusion de l'ordre de 402°C et un point d'ébullition du zinc de l'ordre de 906°C qui sont très nettement inférieurs à celui du métal de base, c'est-à-dire des tôles à assembler, et du métal d'apport, c'est-à-dire du fil fusible. De ce fait, il est donc vaporisé pendant l'opération de soudage de par une action directe de l'arc électrique mais aussi par simple conduction thermique en avant et sur les bords du bain de fusion.In general, zinc, which is the main coating for this type of sheet, is characterized by a melting point of around 402 ° C and a boiling point of zinc of around 906 ° C which are very much lower than that of the base metal, that is to say the sheets to be joined, and the filler metal, that is to say the fusible wire. Therefore, it is vaporized during the welding operation by a direct action of the electric arc but also by simple thermal conduction in front and on the edges of the weld pool.
En amont du bain de fusion, les vapeurs de zinc viennent perturber la protection gazeuse et le transfert, et occasionner ainsi des porosités dans le cordon mais également des instabilités et des projections. Ce phénomène est d'autant plus sensible que l'épaisseur du revêtement est importante par rapport à l'épaisseur soudée et que les configurations de joint, en particulier de type à clin qui sont retenues majoritairement dans les applications du secteur automobile, présentent à l'interface deux couches de zinc jointives emprisonnées qui aggravent les conditions de dégazage. Sur le plan de l'application, si les tolérances d'acceptation de porosités sont bien définies pour ce qui concerne les porosités non-débouchantes, la tolérance est généralement nulle pour les porosités débouchantes vis-à-vis des critères d'aspect, c'est-à-dire l'esthétique, et des conditions de mise en peinture subséquentes sur les chaînes de fabrication de véhicules. L'alternative du soudo-brasage présente également l'avantage d'un apport d'énergie sensiblement réduit puisque seule une fusion du fil est nécessaire et non des tôles, et la quantité de zinc vaporisée s'en trouve donc fortement réduite par rapport à un soudage conventionnel. Cependant, tous ces avantages sont minorés par le coût du métal d'apport, c'est-à-dire du fil de soudo-brasage devant être utilisé.Upstream of the molten bath, the zinc vapors disturb the gas protection and the transfer, and thus cause porosities in the bead but also instabilities and projections. This phenomenon is all the more sensitive when the thickness of the coating is large compared to the welded thickness and when the joint configurations, in particular of the lap type which are mainly used in applications in the automotive sector, present to the interface two trapped contiguous zinc layers which worsen the degassing conditions. In terms of application, if the acceptance tolerances for porosities are well defined with regard to non-emerging porosities, the tolerance is generally zero for the porousities vis-à-vis the appearance criteria, c 'is to say the aesthetics, and subsequent painting conditions on vehicle production lines. The alternative of soldering also has the advantage of a significantly reduced energy input since only a fusion of the wire is necessary and not of the sheets, and the quantity of zinc vaporized is therefore greatly reduced compared to conventional welding. However, all these advantages are reduced by the cost of the filler metal, that is to say the soldering wire to be used.
En résumé, le problème qui se pose spécifiquement en soudage d'éléments dédiés au secteur de la construction automobile est que, comme expliqué ci-avant, les procédés de soudage par court-circuit et puisé ne permettent pas de répondre simultanément aux exigences en termes de maîtrise des pénétrations et déformations, de par l'énergie excédentaire restituée à la tôle, ou de maîtrise des projections de par l'énergie importante à mettre en œuvre pour obtenir le détachement des gouttes de métal fondu, alors que le procédé de soudo-brasage conduit à des avantages en termes de qualité et de confort de soudage mais au détriment d'un coût .global beaucoup plus élevé du procédé dû à l'utilisation de fil fusible de brasage en alliages spéciaux plutôt onéreux.In summary, the problem which arises specifically in welding elements dedicated to the automotive construction sector is that, as explained above, the short-circuit and pulsed welding methods do not make it possible to simultaneously meet the requirements in terms control of penetrations and deformations, by the excess energy returned to the sheet, or control of projections by the significant energy to be used to obtain the detachment of the drops of molten metal, while the welding process brazing leads to advantages in terms of welding quality and comfort but at the expense of a much higher overall cost of the process due to the use of fusible brazing wire made of rather expensive special alloys.
Le but de l'invention est alors de résoudre ces problèmes de l'art antérieur en proposant une solution industrielle parfaitement adaptée au secteur de la fabrication de véhicules automobiles permettent d'obtenir une absence de projections, une mise en œuvre d'une énergie minimale, des vitesses de soudage plus élevées, des pénétrations et déformations réduites des tôles.The object of the invention is then to solve these problems of the prior art by proposing an industrial solution perfectly suited to the motor vehicle manufacturing sector, making it possible to obtain an absence of projections, an implementation of minimal energy. , higher welding speeds, reduced penetrations and deformations of the sheets.
La solution de l'invention est alors un procédé de soudage à l'arc électrique mettant en œuvre d'un fil fusible soumis à un mouvement mécanique cyclique, alternativement en rapprochement puis en éloignement par rapport aux pièces à souder, de manière à créer un court-circuit entre l'extrémité du fil fusible et au moins une des pièces à assembler et à ainsi déposer du métal fondu pour réaliser progressivement un joint de soudure entre lesdites pièces, caractérisé en ce que les pièces à assembler sont des éléments constitutifs d'un véhicule automobile.The solution of the invention is then an electric arc welding process using a fusible wire subjected to a cyclic mechanical movement, alternately in approach and then away from the parts to be welded, so as to create a short circuit between the end of the fusible wire and at least one of the parts to be assembled and thus to deposit molten metal to progressively produce a solder joint between said parts, characterized in that the parts to be assembled are constituent elements of a motor vehicle.
Selon le cas, le procédé de l'invention peut comprendre l'une ou plusieurs des caractéristiques techniques suivantes :Depending on the case, the method of the invention may include one or more of the following technical characteristics:
- le mouvement mécanique cyclique en rapprochement et en éloignement du fil par rapport au bain de fusion est piloté en fréquence, en vitesses, en temps haut de stabilisation de l'arc et en temps bas de contact avec le bain de fusion par au moins un microprocesseur en synchronisation avec une source de courant servant à générer l'arc et le courant de soudage.- the cyclic mechanical movement in approach and away from the wire relative to the weld pool is controlled in frequency, in speeds, in high time of arc stabilization and in low time of contact with the weld pool by at least one microprocessor in synchronization with a current source used to generate the arc and the welding current.
- les éléments à souder ont une épaisseur inférieure à 5 mm de préférence comprise entre 0.5 et 2 mm.- the elements to be welded have a thickness of less than 5 mm, preferably between 0.5 and 2 mm.
- les éléments à souder comportent un revêtement de zinc sur au moins une de leurs faces.- the elements to be welded have a zinc coating on at least one of their faces.
- les pièces métalliques sont en acier au carbone non allié de haute et très haute limite élastique. - au moins une partie des pièces métalliques à assembler sont en aluminium ou en alliage d'aluminium et choisies parmi les caisses ou parties de caisse, en particulier les jonctions tôles/extrudés ou extrudés /extrudés ; les ouvrants, telles les portières ou les capots ; les éléments de liaisons au sol, tels les bras de suspension, les berceaux, les traverses et les jantes. - au moins une partie des pièces métalliques à assembler sont en aciers inoxydables austénitiques ou ferritiques, en particulier les pots d'échappement ou des parties de pots d'échappement.- the metal parts are made of high and very high yield strength unalloyed carbon steel. - At least a part of the metal parts to be assembled are made of aluminum or an aluminum alloy and chosen from boxes or body parts, in particular sheet / extruded or extruded / extruded junctions; openings, such as doors or hoods; ground connection elements, such as suspension arms, cradles, sleepers and rims. - At least part of the metal parts to be assembled are made of austenitic or ferritic stainless steels, in particular the exhaust pipes or parts of the exhaust pipes.
- au moins une partie des éléments à assembler choisis dans le groupe formé par la caisse, le bas de caisse, les flancs raboutés, les longerons, les passage de roues, les traverses sous-sièges, les renforts de pieds, les traverses de planches de bord, les traverses avant, les absorbeurs de chocs et le berceau moteur.- at least a part of the elements to be assembled chosen from the group formed by the body, the underbody, the butted sides, the side members, the wheel arches, the under-seat crosspieces, the foot reinforcements, the board crosspieces edge, the front crossmembers, the shock absorbers and the engine cradle.
- l'intensité du courant, en fonction de la nature et le diamètre ou la section du fil, est comprise entre 30 A et 250 A. - le métal d'apport se présente sous forme de fil de diamètre compris entre 1.2 et 3.2 mm ou de feuillard de section comprise entre 0.5 x 4 et 0.6x 5 mm2.- the intensity of the current, depending on the nature and the diameter or the section of the wire, is between 30 A and 250 A. - the filler metal is in the form of wire with a diameter between 1.2 and 3.2 mm or strip of section between 0.5 x 4 and 0.6x 5 mm 2 .
- le fil d'apport est en acier non allié ou faiblement allié, en acier inoxydable austénitique ou ferritique, en nickel ou alliages de nickel, en cuivre ou en alliages de cuivre, en aluminium ou alliages d'aluminium.- the filler wire is made of unalloyed or low alloyed steel, austenitic or ferritic stainless steel, nickel or nickel alloys, copper or copper alloys, aluminum or aluminum alloys.
- les cordons de soudure à réaliser ont une longueur comprise entre 5 et 100 mm, de préférence entre 10 mm et 70 mm. Toutefois, dans certaines applications, on peut également souder des cordons continus de longueur plus importantes, par exemple de l'ordre du mètre dans le cas des pots d'échappements, voire de plusieurs mètres. L'invention concerne aussi un procédé de fabrication de véhicule automobile formés de plusieurs éléments assemblées par un procédé de soudage selon l'invention, de préférence mis en œuvre par un robot de soudage, par exemple sur une chaîne de fabrication de véhicules automobiles. Le principe de l'invention repose sur le fait de forcer un court-circuit à se produire entre le fil fusible et les tôles à assembler grâce à la réalisation d'une descente "mécanique" du fil en direction des tôles à souder de manière à déposer la goutte de métal fondu dans le bain de fusion, puis d'opérer un retrait mécanique subséquent du fil après dépôt de la goutte métallique. Ce cycle de descente et remontée mécaniques du fil doit être piloté en fréquence, en vitesses, en temps haut et en- temps bas par un ou plusieurs microprocesseur en synchronisation avec la source de courant.- the weld beads to be produced have a length of between 5 and 100 mm, preferably between 10 mm and 70 mm. However, in certain applications, it is also possible to weld continuous cords of greater length, for example of the order of a meter in the case of exhaust pipes, or even of several meters. The invention also relates to a method of manufacturing a motor vehicle formed from several elements assembled by a welding method according to the invention, preferably implemented by a welding robot, for example on a production line for motor vehicles. The principle of the invention is based on the fact of forcing a short circuit to occur between the fusible wire and the sheets to be assembled by means of a "mechanical" descent of the wire in the direction of the sheets to be welded so as to deposit the drop of molten metal in the melt, then carry out a subsequent mechanical removal of the wire after depositing the metal drop. This wire descent and ascent cycle must be controlled in frequency, speed, high time and low time by one or more microprocessors in synchronization with the current source.
Dans ces conditions, l'énergie électrique délivrée est strictement destinée à la fusion du fil. Elle est donc réduite d'un facteur 2 à 3 par rapport à celle habituellement appliquée dans un procédé MIG conventionnel.Under these conditions, the electrical energy delivered is strictly intended for melting the wire. It is therefore reduced by a factor of 2 to 3 compared to that usually applied in a conventional MIG process.
L'application de ce procédé est donc particulièrement intéressante dans le secteur de la fabrication des éléments de véhicules automobiles.The application of this method is therefore particularly advantageous in the sector of the manufacture of motor vehicle components.
Les avantages engendrés par cette manière de réaliser le court-circuit et donc le dépôt des gouttes de métal en fusion, seront, d'une part, une absence de projections de par l'apport direct et mécanique du fil fondu dans le bain de fusion et, d'autre part, une énergie entièrement disponible pour la fusion du fil, donc des vitesses de soudage plus élevées autorisant au niveau de l'assemblage des pénétrations et déformations très réduites.The advantages generated by this way of making the short circuit and therefore the deposition of the drops of molten metal, will be, on the one hand, an absence of projections due to the direct and mechanical contribution of the molten wire in the molten bath and, on the other hand, a fully available energy for the fusion of the wire, therefore higher welding speeds allowing very reduced penetrations and deformations at the assembly level.
Suivant les configurations de joint, on peut obtenir des vitesses 2 à 3 fois supérieures à celles obtenues, en mono fil, dans les deux régimes transfert précités de l'art antérieur.Depending on the joint configurations, it is possible to obtain speeds 2 to 3 times higher than those obtained, in single wire, in the two aforementioned transfer regimes of the prior art.
Cette énergie de soudage dédiée essentiellement à la fusion du fil, donc très réduite sur les tôles, entraîne donc une diminution très notable de la vaporisation du zinc en avant et dans le bain de fusion. II en résulte donc une réduction importante des instabilités et des projections mais aussi une limitation de l'altération du revêtement du côté endroit et de part et d'autre du cordon, mais également du côté opposé, c'est-à-dire sur la face envers, qui peut devenir prépondérant dans certains éléments de véhicules, en particulier lorsque qu'on considère la tenue à la corrosion de zones non accessibles avant peinture. L'invention est particulièrement adaptée à l'assemblage de la caisse du véhicule "en blanc" (tôles non pré-peintes ou peintes) à partir des différents éléments constitutifs suivants : bas de caisse, flancs raboutés, longerons hydroformés ou reconstitués, passage de roues, traverses sous siège, renforts de pied de milieu, traverses de planches de bord, traverses avant, longerons et absorbeurs de chocs (hydro-formés ou reconstitués, et berceau moteur.This welding energy dedicated essentially to the melting of the wire, therefore very reduced on the sheets, therefore results in a very noticeable reduction in the vaporization of the zinc before and in the fusion bath. This therefore results in a significant reduction in instabilities and projections but also a limitation in the alteration of the coating on the right side and on either side of the bead, but also on the opposite side, that is to say on the upside down, which can become preponderant in certain vehicle elements, in particular when we consider the corrosion resistance of areas not accessible before painting. The invention is particularly suitable for assembling the body of the vehicle "in white" (sheets not pre-painted or painted) from the following constituent elements: rocker panels, planed sidewalls, hydroformed or reconstituted side rails, passage of wheels, seat crossmembers, middle leg reinforcements, dashboard crossmembers, front crossmembers, side members and shock absorbers (hydro-formed or reconstituted, and engine cradle.
La gamme d'épaisseurs de ces composants emboutis ou hydroformés pouvant être ainsi soudés va de 0.6 à 2 mm.The range of thicknesses of these stamped or hydroformed components that can be thus welded is from 0.6 to 2 mm.
Ces éléments de véhicules sont généralement revêtus double faces par électrozingage ou galvanisation.These vehicle components are generally coated on both sides by electrogalvanizing or galvanizing.
En fonction de la chronologie d'assemblage des composants élémentaires jusqu'à celle des derniers sous-ensembles, les préparations finales, en termes de jeu et de mésalignement, vont donc cumuler l'ensemble des tolérances élémentaires pour atteindre des valeurs nécessitant soit une modification de la procédure de soudage existante, notamment un "balayage", c'est-à-dire un soudage avec oscillation transversales de la torche par rapport au plan de joint, avec réduction de la vitesse de soudage par exemple, soit l'adoption d'un procédé plus flexible, par exemple un procédé de soudobrasage à la place du soudage. Les cordons à réaliser sont des cordons typiquement discontinus de longueur variable entre 15 et 60 mm qui sont 'mécaniquement efficaces' sur toute leur longueur, c'est-à-dire dimensionnés vis-à-vis d'une tenue en fatigue mais aussi de crash-tests frontaux voire latéraux. Il est donc indispensable que les démarrages et les fins de cordons soient aussi bien maîtrisés et sans projections.Depending on the chronology of assembly of the elementary components up to that of the last sub-assemblies, the final preparations, in terms of play and misalignment, will therefore accumulate all of the elementary tolerances to reach values requiring either modification of the existing welding procedure, in particular a "sweep", that is to say a welding with transverse oscillation of the torch relative to the joint plane, with reduction of the welding speed for example, that is the adoption of a more flexible process, for example a braze-brazing process instead of welding. The cords to be produced are typically discontinuous cords of variable length between 15 and 60 mm which are 'mechanically effective' over their entire length, that is to say dimensioned with respect to fatigue resistance but also of frontal or even side crash tests. It is therefore essential that the starts and end of the cords are as well controlled and without projections.
D'autres composants tels que les pots d'échappement sont plutôt réalisés à partir d'acier inoxydables ferritiques ou austénitiques dans des gammes d'épaisseur de 0.6 mm à 2 mm. La criticité de l'opération de soudage est très similaire à celle des caisses, en particulier pour ce qui concerne les préparations et les dégradations possible du métal de base et du catalyseur qu'ils contiennent. Viennent également s'y rajouter des problèmes de tenue en fatigue thermique et tenue à la corrosion. L'invention est ici aussi particulièrement adaptée au soudage à grande vitesse des circulaires, sans projection et sans dégradation des zones thermiquement affectées, des aciers inoxydables ferritiques ainsi que du catalyseur. Pour mettre en œuvre l'invention, on utilise par exemple un générateur de courant de type 480 TRS de LA SOUDURE AUTOGENE FRANÇAISE, une torche de soudage MIG avec dispositif d'amenée de fil, un dévidoir de fil, un dispositif permettant de conférer un mouvement alternatif de va et vient au fil, c'est-à-dire en rapprochement puis en éloignement.Other components such as exhaust pipes are rather made from ferritic or austenitic stainless steel in thickness ranges from 0.6 mm to 2 mm. The criticality of the welding operation is very similar to that of the boxes, in particular with regard to the preparations and possible degradations of the base metal and of the catalyst which they contain. There are also problems with thermal fatigue resistance and corrosion resistance. The invention is here also particularly suitable for high speed welding of circulars, without projection and without degradation of the thermally affected areas, ferritic stainless steels as well as the catalyst. To implement the invention, use is made, for example, of a current generator of the 480 TRS type from LA SOUDURE AUTOGENE FRANÇAISE, a MIG welding torch with wire feed device, a wire feeder, a device making it possible to impart a reciprocating movement back and forth over the wire, that is to say in approaching then in moving away.
L'installation permettant de mettre en œuvre l'invention se compose d'un module de dévidage comprenant un système d'entraînement de galets presseurs couplés à un moteur électrique avec ou sans réducteur intermédiaire. La régulation de dévidage de fil peut assuré par un système de dynamo tachymétrique par exemple ou par un autre système de régulation approprié.The installation making it possible to implement the invention consists of a reeling module comprising a drive system for pressure rollers coupled to an electric motor with or without an intermediate reducer. The wire feed regulation can be ensured by a tacho dynamo system for example or by another suitable regulation system.
L'installation comprend aussi un faisceau d'amenée de fil formé d'une gaine concentrique dans lequel transitent le fil fusible, le gaz de soudage et, suivant le cas, le circuit de refroidissement de la torche ; un module de dévidage situé au plus près de la torche, lequel peut comporter un ou plusieurs moteurs de type pas-à-pas pour entraîner le fil fusible à la vitesse moyenne désirée et assurer le mouvement descente et remontée nécessaire au fonctionnement du procédé ; un générateur de soudage tel que décrit précédemment ou analogue ; un module de pilotage à microprocesseur pour commander la vitesse et le mouvement du fil, ainsi que l'intensité délivrée par le générateur, en particulier la forme de l'onde de courant.The installation also includes a wire supply bundle formed by a concentric sheath in which the fusible wire, the welding gas and, as the case may be, the torch cooling circuit pass; a reeling module located as close as possible to the torch, which may include one or more stepping type motors for driving the fusible wire at the desired average speed and ensuring the downward and upward movement necessary for the operation of the process; a welding generator as described above or the like; a microprocessor control module for controlling the speed and movement of the wire, as well as the intensity delivered by the generator, in particular the shape of the current wave.
En fonction de la nuance du métal de base et du métal d'apport, la protection gazeuse sera faite par exemple avec un gaz de type mélanges gazeux Ar+C02 ou Ar+C02+02 pour le soudage des aciers carbone non alliés ou faiblement alliés, ou de type mélange Ar+H2+C02 pour le soudo-brasage de ces mêmes matériaux, ou mélange de type Ar+H2+C02 ou Ar+He+C02 pour les aciers inoxydables austénitiques et ferritiques, ainsi que pour le nickel et ses alliages, ou encore de type argon ou mélange Ar+He, Ar+02 ou Ar+He+02 pourDepending on the grade of the base metal and the filler metal, the gas protection will be made for example with a gas of the gas mixture type Ar + C0 2 or Ar + C0 2 +0 2 for the welding of unalloyed carbon steels or weakly alloyed, or of the Ar + H 2 + C0 2 mixture type for the soldering of these same materials, or of the Ar + H2 + C0 2 or Ar + He + C0 2 type mixture for austenitic and ferritic stainless steels, as well as for nickel and its alloys, or of the argon type or mixture Ar + He, Ar + 02 or Ar + He + 0 2 for
"Valuminîum et ses alliages. Le procédé de soudage MIG à court-circuit forcé mécaniquement dont on peut trouver des détails supplémentaires notamment dans le document Direct Control of the Material Transfer : The Controlled Short Circuit (CSC)-MIG Process, de G. Huismann, p.165-172, publié dans Gas Métal Arc Welding for the 21st Century, AWS/EWI Conférence 6-8 décembre 2000, Orlando, Floride, est particulièrement adapté au soudage d'éléments constitutifs de véhicules automobiles car il permet :"Valuminium and its alloys. The mechanically forced short-circuit MIG welding process, of which further details can be found in particular in the document Direct Control of the Material Transfer: The Controlled Short Circuit (CSC) -MIG Process, by G. Huismann , p.165-172, published in Gas Métal Arc Welding for the 21st Century, AWS / EWI Lecture 6-8 December 2000, Orlando, Florida, est particularly suitable for welding components of motor vehicles because it allows:
- un soudage de tôles très fines sou faible énergie et à vitesse de soudage élevée, donc engendrant de faibles déformations dimensionnelles ou distorsions sur une caisse assemblée de véhicule,- welding of very thin sheets under low energy and at high welding speed, thus generating small dimensional deformations or distortions on an assembled vehicle body,
- une stabilité forcée du procédé donc une absence de projections sur les zones courantes mais aussi sur les zones de démarrage et de fond de cordon,- forced stability of the process therefore an absence of projections on the current areas but also on the start-up and bottom areas of the bead,
- un respect des matériaux assemblés puisque les zones affectées sont réduites puisque une faible énergie est restituée au métal de base, et - un respect du revêtement de zinc grâce à la faible énergie mise en œuvre qui engendre donc une faible vaporisation du zinc sur les différentes faces des assemblages. - respect for the assembled materials since the affected areas are reduced since low energy is restored to the base metal, and - respect for the zinc coating thanks to the low energy used which therefore generates low vaporization of the zinc on the various faces of assemblies.
Claims
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0201215 | 2002-02-01 | ||
| FR0201215A FR2835456B1 (en) | 2002-02-01 | 2002-02-01 | METHOD FOR WELDING ELEMENTS OF MOTOR VEHICLES, PARTICULARLY PLANED SIDES |
| PCT/FR2003/000154 WO2003064096A2 (en) | 2002-02-01 | 2003-01-17 | Method of welding motor vehicle elements, in particular tailored blanks |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1474262A2 true EP1474262A2 (en) | 2004-11-10 |
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ID=27619822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP03709888A Withdrawn EP1474262A2 (en) | 2002-02-01 | 2003-01-17 | Method of welding motor vehicle elements, in particular tailored blanks |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US7176410B2 (en) |
| EP (1) | EP1474262A2 (en) |
| FR (1) | FR2835456B1 (en) |
| WO (1) | WO2003064096A2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2835457B1 (en) | 2002-02-01 | 2004-04-02 | Air Liquide | TERNARY GASEOUS MIX FOR USE IN SOLDERING OF GALVANIZED PARTS |
| US7498543B2 (en) * | 2006-03-22 | 2009-03-03 | Gm Global Technology Operations, Inc. | Method for joining or repairing metal surface parts |
| DE102008024977A1 (en) | 2008-05-23 | 2009-11-26 | Linde Ag | Method of arc joining |
| US8410400B2 (en) * | 2008-12-12 | 2013-04-02 | Material Sciences Corporation | Welded metal laminate structure and method for welding a metal laminate structure |
| DE102009013322A1 (en) * | 2009-03-18 | 2010-09-30 | Benteler Automobiltechnik Gmbh | bumper assembly |
| JP6499557B2 (en) * | 2015-09-08 | 2019-04-10 | 日新製鋼株式会社 | Welding method for austenitic stainless steel sheet |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2827547A (en) * | 1955-05-20 | 1958-03-18 | Smith Corp A O | Apparatus for welding vehicle frames |
| US3339057A (en) * | 1966-07-28 | 1967-08-29 | Arthur A Bernard | Mechanical intermittent arc welding |
| US3581053A (en) * | 1967-12-05 | 1971-05-25 | Union Carbide Corp | Synchro-arc metal transfer |
| JPS56109169A (en) * | 1980-02-01 | 1981-08-29 | Mitsubishi Electric Corp | Arc length control unit |
| DE19738785C2 (en) * | 1997-09-04 | 2001-12-13 | Leipold & Co Gmbh | Arc welding device with melting electrode |
| KR100646437B1 (en) * | 1999-03-18 | 2006-11-14 | 가부시키가이샤 야스카와덴키 | Consumable electrode arc welding method and device |
| AT409832B (en) * | 1999-04-26 | 2002-11-25 | Fronius Schweissmasch Prod | WELDING PROCESS AND WELDING DEVICE FOR CARRYING OUT THE WELDING PROCESS |
| JP2001001142A (en) * | 1999-06-24 | 2001-01-09 | Daihen Corp | Control method for arc length of pulse arc welding |
-
2002
- 2002-02-01 FR FR0201215A patent/FR2835456B1/en not_active Expired - Fee Related
-
2003
- 2003-01-17 WO PCT/FR2003/000154 patent/WO2003064096A2/en not_active Ceased
- 2003-01-17 US US10/503,263 patent/US7176410B2/en not_active Expired - Fee Related
- 2003-01-17 EP EP03709888A patent/EP1474262A2/en not_active Withdrawn
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| See references of WO03064096A3 * |
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| Publication number | Publication date |
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| WO2003064096A3 (en) | 2004-03-11 |
| US7176410B2 (en) | 2007-02-13 |
| FR2835456B1 (en) | 2004-04-02 |
| FR2835456A1 (en) | 2003-08-08 |
| WO2003064096A2 (en) | 2003-08-07 |
| US20050139583A1 (en) | 2005-06-30 |
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