FR3140292A1 - Laser beam welding machine - Google Patents

Abstract

Laser beam welding machine. The invention relates to a welding machine (1) of at least two parts to be welded (2), configured to be movable along said parts to be welded (2), the welding machine (1) extending in one direction main longitudinal extension (L) and comprising at least one pair of drive wheels (26) intended to set in motion said welding machine (1) relative to the parts to be welded (2), the welding machine (1 ) comprising at least one welding device (30) of the at least two parts to be welded (2), the welding device (30) comprising at least one means (32) intended to channel a laser beam so as to weld the parts to solder (2). Figure 1

Description

Laser beam welding machine

The present invention relates to welding machines making it possible to weld together constituent parts of a transport tank, for example liquefied gas.

Current welding machines include drive wheels as well as a drive member capable of rotating at least the drive wheels along the parts to be welded. Usually, welding machines include welding rolls in order to weld the parts to be welded. The welding wheels are supplied with electric current when the welding machine moves by means of an electric current unit, ensuring the welding of the parts to be welded. Roll welding is particularly effective for welding parts to be welded made of Invar™.

Invar™ has interesting resistance properties, particularly for use within a transport tank, for example liquefied gas, and makes it possible, among other things, to guarantee optimal transport of said liquefied gas. However, although it is efficient, Invar™ is expensive and its use therefore generates significant manufacturing costs for the manufacturer. Thus, new alloys are trying to be used to replace Invar™. For example, an alloy with a high manganese content makes it possible to replace Invar™ in tanks, and has an expansion coefficient between that of Invar™ and that of stainless steel, but with a lower cost. However, such an alloy with a high manganese content is complex to weld with current welding machines.

Thus, the use of alloys with a high manganese content instead of Invar™ requires the development and use of suitable welding machines.

The aim of the present invention is therefore to provide a welding machine capable of welding alloys with a high manganese content while maintaining a compact welding machine.

The invention therefore relates to a laser beam welding machine for at least two parts to be welded, configured to be mobile along said parts to be welded, the welding machine extending in a direction of main longitudinal elongation and comprising at least one pair of drive wheels intended to set said welding machine in motion relative to the parts to be welded, the welding machine comprising at least one device for laser beam welding of the at least two parts to be welded, the device for welding welding comprising at least one means intended to channel a laser beam capable of welding the parts to be welded.

The welding machine according to the invention can be used for example to weld two raised edges together and/or with an anchoring wing of a waterproof membrane constituting a wall of a storage and/or transport tank. cryogenic products such as liquefied natural gas. For example, the welding machine can weld raised edges of two adjacent parts named, first part to be welded and second part to be welded, in order to form the waterproof membrane of the wall of the cryogenic product storage and/or transport tank. Alternatively, the welding machine can weld at least one of the raised edges with the anchoring wing, forming a third part to be welded, placed between the two raised edges of the two adjacent parts. We therefore understand that the part to be welded may be one of the raised edges or the anchoring wing.

To this end, the welding machine comprises at least the pair of drive wheels ensuring, by means of a drive member, the movement of the welding machine along the parts to be welded in a rectilinear welding direction, otherwise called the direction of advancement of the welding machine. The drive member may for example be an electric, hydraulic, pneumatic or even mechanical drive member. Preferably, the drive member in the context of the invention is an electric motor.

The advantage of using a laser beam to weld the parts to be welded is that it allows alloys such as alloys with a high manganese content to be welded. Thus, the invention provides a compact welding machine capable of welding a greater diversity of alloys and also allowing alloys of different nature to be welded together.

According to one characteristic of the invention, the welding machine comprises at least one drive member capable of rotating at least one of the drive wheels.

According to one characteristic of the invention, the means intended to channel the laser beam comprises at least one focusing lens, a reflection member and at least one circulation conduit surrounding the laser beam.

We understand that the focusing lens makes it possible to focus the laser beam conveyed, for example, by means of an optical fiber. The circulation conduit also makes it possible to protect a circulation path of the laser beam so that the latter is not disturbed by the external environment. The reflection member makes it possible, among other things, to reflect the laser beam without modifying its focal length.

According to an optional aspect of the invention, the reflection member is for example a mirror. Advantageously, the welding machine includes means for adjusting the position of the reflection member, which makes it possible to adjust the positioning of the laser beam on the parts to be welded.

According to one example, the reflection member comprises at least one material resistant to the heat of the laser beam, such material being in particular quartz. Alternatively or additionally, the reflection member may comprise a cooling system configured to maintain the temperature of the reflection member below a temperature threshold. These arrangements make it possible to avoid any deformation, which would deteriorate the quality and/or position of the beam.

According to one characteristic of the invention, the laser beam circulation conduit extends from the focusing lens to at least one welding zone of the parts to be welded.

We understand that the welding zone corresponds to the area of the parts to be welded intended to receive the laser beam. We also understand that the welding zone evolves as the welding machine advances along the parts to be welded.

According to one characteristic of the invention, the reflection member is arranged in the circulation conduit between the focusing lens and the welding zone.

According to one characteristic of the invention, the circulation conduit is bent in such a way as to form an angular portion of the circulation conduit, the reflection member being arranged in the angular portion of the circulation conduit. Thus, we understand that the reflection member is configured in such a way as to modify the trajectory of the laser beam in the circulation conduit so that it corresponds to the shape of the circulation conduit.

According to one characteristic of the invention, the welding device comprises at least one housing forming a chamber around the welding zone, the housing being arranged at one end of the circulation conduit, opposite the focusing lens.

According to one characteristic of the invention, a neutral gas is distributed in the chamber formed by the housing, at least at the welding zone.

According to one characteristic of the invention, the welding device comprises at least one pair of pressure rollers intended to press the parts to be welded against each other at the welding zone.

The pressure rollers are intended to press the parts to be welded together with a maximum clearance between sheets of 0.2mm. Furthermore, the pressure rollers are arranged in the chamber delimited by the housing.

A pair of pressure rollers means two pressure rollers arranged on either side of the parts to be welded along a straight line perpendicular to a plane of the parts to be welded. Optionally, the pressure rollers can be cooled.

According to one characteristic of the invention, the laser beam falls into a plane in which an axis of rotation of the at least two pressure rollers passes.

According to one characteristic of the invention, the welding device comprises an element for receiving the laser beam arranged in the housing and configured to be cooled. The laser beam receiving element makes it possible to absorb the residual optical energy of the laser beam and is connected to a cooling circuit in order to cool it.

Furthermore, the parts to be welded are arranged between the reflection member and the receiving element according to the trajectory of the laser beam. We then understand that the receiving element absorbs the residue of the laser beam once it has passed through the welding zone.

According to an example of the invention, the receiving element is made of a metallic or ceramic material.

According to one characteristic of the invention, the laser beam receiving element is configured to absorb a residual part of the laser beam after its passage through the parts to be welded.

According to an example of the invention, the welding device comprises another pair of pressure rollers on the other side of the welding zone, the laser beam falling in a plane in which the axis of rotation of the at least two pairs of pressure rollers.

According to one characteristic of the invention, the focusing lens of the welding device is connected to an optical energy source external to the welding machine, in particular by an optical fiber.

According to one characteristic of the invention, the laser beam has a power of between 1200W and 3000W.

According to an example of the invention, for an alloy with a manganese content of at least 25%, the power of the laser beam is between 1250W and 3000W. For an alloy composed of at least 36% nickel, the power of the laser beam is between 1250W and 2500W.

According to one characteristic of the invention, the drive wheels are configured to move the welding machine along the parts to be welded at a speed of between 2m/min and 6m/min.

According to an example of the invention, for an alloy with a manganese content of at least 25%, the speed of advancement of the welding machine is between 2m/min and 5.5m/min. For an alloy composed of at least 36% nickel, the forward speed of the welding machine is between 2m/min and 4.8m/min.

According to one characteristic of the invention, the driving wheels each extend in a intersecting plane relative to a plane of the parts to be welded, the intersecting plane of at least one of the driving wheels being distinct from a plane perpendicular to the plane of the parts to be welded.

According to one characteristic of the invention, at least two pairs of drive wheels are arranged on either side of the housing of the welding device in a longitudinal direction of the welding machine.

According to an example of the invention, the pairs of drive wheels are desynchronized in rotation relative to each other. In other words, the two pairs of drive wheels are able to be rotated by the drive member at different speeds from each other.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for information purposes in relation to the drawings in which:

is a general perspective view of a welding machine according to the invention capable of welding parts to be welded;

is a close-up view of a welding device of the welding machine of the ;

is a close-up view of a housing of the welding device of the .

It should first be noted that if the figures present the invention in detail for its implementation, these figures can of course be used to better define the invention, if necessary. It should also be noted that these figures only show examples of embodiments of the invention. Finally, the same references designate the same elements in all of the figures.

There illustrates a welding machine 1 configured to move along at least two parts to be welded 2. More precisely, the parts to be welded 2 are for example strips and constitute a waterproof membrane 6 of a wall 8 of a storage and/or transport tank for products maintained in the liquid state at a temperature below -100°C at atmospheric pressure, for example liquefied natural gas.

The welding machine 1 can for example make it possible to weld directly against each other a first raised edge 4 and a second raised edge respectively of a first part to be welded 2a and a second adjacent part to be welded 2b. According to another example of the invention, the welding machine can weld at least one of the raised edges 4 of one of the first part to be welded 2a and/or the second part to be welded 2b, with an anchoring wing 12 forming a third part to be welded visible in Figures 2 and 3, said anchoring wing 12 being arranged between two adjacent raised edges.

More particularly, the anchoring wing 12, visible in Figures 2 and 3, is anchored to an insulator belonging to the tank wall and is arranged between two adjacent raised edges. Such welding of at least two of the parts to be welded 2a, 2b forms a weld bead 14, visible in Figures 2 and 3, on at least one of the first raised edge 4 and/or the second raised edge, extending the along a welding axis S. The weld bead 14 formed between the at least two parts to be welded 2 makes it possible, among other things, to ensure sealing between said parts to be welded 2, and thus contributes to the sealing of the membrane 6 constituting the wall 8 of the tank storage and/or transport of cryogenic products.

Welding machine 1 shown in comprises at least one body 16 which has a substantially parallelepiped shape and which extends in a direction of main elongation parallel to a longitudinal direction L of the welding machine 1. The body 16 of the welding machine 1 comprises in particular an end front 18 and a rear end 20, opposite each other in the longitudinal direction L of the welding machine 1. It is also understood that the notion of front/rear of the body 16 of the welding machine 1 refers to a direction of advancement A of the welding machine 1 along the parts to be welded 2, parallel to the welding axis S and to the longitudinal direction L of said welding machine 1. Furthermore, the body 16 of the welding machine 1 comprises an upper face 22 and a lower face 24, opposite each other in a vertical direction V of the welding machine 1, perpendicular to its longitudinal direction L, the lower face 24 being the face of the body 16 of the welding machine 1 facing the parts to be welded 2.

The welding machine 1 according to the invention, visible at , comprises at least one pair of drive wheels 26 intended to set the welding machine 1 in motion relative to the parts to be welded 2, and at least one drive member, not visible, capable of rotating the at minus a pair of drive wheels 26.

More precisely, the at least one pair of drive wheels 26 is arranged at the lower face 24 of the body 16 of the welding machine 1 such that it is in contact with at least one of the parts to be weld 2. Thus, the rotation of the at least one pair of drive wheels 26 operated by the drive member allows said pair of drive wheels 26, arranged in contact with the parts to be welded 2, to cause the movement of the welding machine 1 along the parts to be welded 2 following a rectilinear translational movement parallel to the direction of advancement A of the welding machine 1.

More precisely, each of the wheels of the pair of drive wheels 26 is in contact with one of the parts to be welded 2. According to the example of the invention illustrated, the welding machine 1 comprises a first pair of wheels drive wheels 26a and a second pair of drive wheels 26b arranged respectively at the front end 18 and at the rear end 20 of the body 16 of the welding machine 1. It is further understood that the drive wheels 26 of each pair of drive wheels 26a, 26b are opposed to each other in a transverse direction T of the welding machine 1, perpendicular to the longitudinal direction L and vertical V. Thus, the drive wheels 26 of the same pair of drive wheels extend on either side of the parts to be welded 2.

According to another example of the invention, the drive wheels each extend in a plane intersecting with respect to a plane of the parts to be welded 2, and for at least one of the drive wheels the plane in which it is extends is perpendicular to the plane of one of the raised edges 4. Such a characteristic allows in particular the welding machine to be held alone against the side walls or against the upper wall of the tank during its movement.

As mentioned previously, the welding machine 1 comprises at least one drive member ensuring the rotation of the drive wheels 26 and which can take the form of an electric, hydraulic, pneumatic or even mechanical drive member. . Preferably, the drive member according to the invention is an electric motor.

The welding machine 1 according to the invention comprises at least one welding device 30 of the at least two parts to be welded 2, visible at the . The welding device 30 notably comprises at least one means 32 intended to channel a laser beam 34 so as to weld the parts to be welded 2.

The welding device 30 will now be described in more detail using Figures 2 and 3.

As mentioned previously, the welding device 30 comprises the means 32 intended to channel the laser beam 34 consisting of at least one focusing lens 36, a reflection member 38 and at least one circulation conduit 40 surrounding the laser beam 34 The focusing lens 36 makes it possible, among other things, to focus the laser beam 34 which is conveyed for example by optical fiber 51 from a laser source external to the welding machine 1 and here not visible. Thus, we understand that the laser beam 34 coming from the focusing lens 36 is surrounded by the circulation conduit 40 such that the latter protects both a user of the welding machine 1 from the laser beam 34 and at the same time the laser beam 34 itself from the external environment being able to disrupt its trajectory. To this end, the circulation conduit 40 of the laser beam 34 extends from the focusing lens 36 to at least one welding zone 44 of the parts to be welded 2. By welding zone 44 is meant a portion on the parts to weld 2 on which the weld bead 14 mentioned above must form.

As particularly visible at the , the circulation conduit 40 is bent so as to form an angular portion 46 of the circulation conduit 40. Such a structure of the circulation conduit 40 makes it possible in particular to optimize the dimensions of the welding machine 1 by limiting the bulk of said circulation conduit 40 of the laser beam 34. The reflection member 38 is then disposed in the angular portion 46 of the circulation conduit 40. In other words, the reflection member 38 is disposed in the circulation conduit 40 between the focusing lens 36 and the welding zone 44. It is then understood that the function of the reflection member 38 is to deflect the rectilinear trajectory of the laser beam 34 at the outlet of the focusing lens 36. According to the example of the invention illustrated, the angular portion 46 of the circulation conduit 40 forms a substantially right angle of the circulation conduit 40 and the reflection member 38 is arranged in the angular portion 46 of the circulation conduit 40 such that it deflects the laser beam 34 by 90° in order to follow the trajectory of the circulation conduit 40. According to an example of the invention, the reflection member 38 is a mirror.

According to the invention, the welding device 30 comprises at least one housing 48 delimiting a chamber 50 around the welding zone 44, the housing 48 being disposed at one end of the circulation conduit 40, opposite the focusing lens 36. As visible in Figures 2 and 3, the housing 48 includes an opening 52 configured to allow the parts to be welded 2 to pass through the housing 48.

Furthermore, according to an example of the invention, the housing can comprise a device for projecting a neutral gas towards the welding zone so as to avoid oxidation of the weld bead which results from welding by the laser beam. The neutral gas projection device is then at least partly positioned in chamber 50.

According to the invention, the housing 48 of the welding device 30 is dimensioned such that it is capable of housing at least one pair of pressure rollers 54 intended to press the parts to be welded 2 against each other at the level of the welding zone 44. In other words, the pressure rollers 54 of the at least one pair of pressure rollers 54 are arranged on either side of the welding zone 44 in such a way that they press the parts to be welded 2 against each other.

According to an example of the invention, the parts to be welded 2 are pressed against each other such that the welding zone 44 has a maximum clearance between sheets of 0.2mm spacing between said parts to be welded 2 Furthermore, it is understood that the pressure rollers 54 are connected to a system for pressurizing the pressure rollers 54 in order to press them against the parts to be welded 2 at the welding zone 44.

Furthermore, according to the invention, the laser beam 34 is inscribed in a plane in which the axis of rotation R of the at least two pressure rollers 54 passes, visible at the . Advantage is taken of such a characteristic in that it allows the laser beam 34 to pass through the welding zone 44 where the parts to be welded 2 are most in contact with each other.

According to the example of the invention illustrated, the two pressure rollers 54 mentioned above are called first pair 54a of pressure rollers 54. According to this example, the welding machine 1 comprises a second pair 54b of pressure rollers 54. The first pair 54a and the second pair 54b of pressure rollers 54 are on either side of the laser beam 34. The pressure rollers 54 of the second pair of pressure rollers 54b each have an axis of rotation R which fits into the common plane with the axes of rotation R of the other pressure rollers 54 of the first pair of pressure rollers 54, and optionally with the laser beam 34. We then understand that the pressure rollers 54 of the second pair 54b of pressure rollers are arranged on the other side of the welding zone 44 relative to the first pair 54a of pressure rollers 54, in the vertical direction V of the welding machine 1. This makes it possible to optimize the plating of the parts to be welded 2 at the level of the welding zone welding 44.

According to one characteristic of the invention, the welding device 30 comprises a receiving element 56 of the laser beam 34 arranged in the housing 48 and configured to be cooled, for example by means of a cooling circuit, not visible. In other words, the receiving element 56 is configured to absorb a residual part of the laser beam 34 following its passage through the parts to be welded 2. We then understand that the parts to be welded are arranged between the focusing lens 36 and the receiving element 56 along the trajectory of the laser beam 34. According to an example of the invention, the receiving element 56 is made of metallic material, for example copper, or of ceramic material. It is understood, however, that the receiving element 56 can be made of any material capable of being cooled.

Advantage is taken of the welding machine 1 according to the invention in that the use of a laser beam 34 to weld the parts to be welded 2 makes it possible to weld different metals with the same welding machine 1. For example, the welding machine 1 according to the invention makes it possible to weld parts to be welded 2 made of Invar™ or even of an alloy with a high manganese content. By high manganese content we mean a content of at least 25% in an alloy.

For example, for an alloy with a manganese content of at least 25%, the power of the laser beam 34 is between 1250W and 3000W. For an alloy composed of at least 36% nickel, the power of the laser beam 34 is between 1250W and 25000W.

Also, depending on the type of metals to be welded, the drive wheels 26 will adapt their rotation speed in order to optimize the welding of the parts to be welded 2. For example, for an alloy with a manganese content of at least 25% , the forward speed of the welding machine 1 is between 2m/min and 5.5m/min. For an alloy composed of at least 36% nickel, the advancement speed of the welding machine 1 is between 2m/min and 4.8m/min.

According to one option, the welding machine may include a camera system such as a camera. Such a system makes it possible to control the quality of the weld. This camera system can point directly at the welding zone 44, so as to observe the creation of the weld. Alternatively, this camera system can point towards the rear of the welding machine so as to observe the weld after the welding machine has passed.

The invention as it has just been described cannot, however, be limited to the means and configurations exclusively described and illustrated, and also applies to all equivalent means or configurations and to any combination of such means or configurations.

Claims (13)

Laser beam welding machine (1) of at least two parts to be welded (2), configured to be movable along said parts to be welded (2), the welding machine (1) extending in a direction of main longitudinal extension (L) and comprising at least one pair of drive wheels (26) intended to set in motion said welding machine (1) relative to the parts to be welded (2), the welding machine (1) comprising at least one laser beam welding device (30) of the at least two parts to be welded (2), the welding device (30) comprising at least one means (32) intended to channel a laser beam (34) capable of welding the parts to be welded (2). Welding machine (1) according to claim 1, comprising at least one drive member capable of rotating at least one of the drive wheels (26). Welding machine (1) according to any one of claims 1 or 2, in which the means (32) intended to channel the laser beam (34) comprises at least one focusing lens (36), a reflection member (38 ) and at least one circulation conduit (40) surrounding the laser beam (34). Welding machine (1) according to claim 3, in which the circulation conduit (40) of the laser beam (34) extends from the focusing lens (36) to at least one welding zone (44) of the parts to weld (2). Welding machine (1) according to claim 4, in which the reflection member (38) is arranged in the circulation conduit (40) between the focusing lens (36) and the welding zone (44). Welding machine (1) according to any one of claims 4 or 5, in which the welding device (30) comprises at least one housing (48) forming a chamber (50) around the welding zone (44), the housing (48) being disposed at one end of the circulation conduit (40), opposite the focusing lens (36). Welding machine (1) according to any one of claims 1 to 6 in combination with claim 4, in which the welding device (30) comprises at least one pair of pressure rollers (54) intended to press the parts to be welded (2) against each other at the welding zone (44). Welding machine (1) according to claim 7, in which the laser beam (34) falls into a plane in which an axis of rotation (R) of the at least two pressure rollers (54) passes. Welding machine (1) according to claim 6, in which the welding device (30) comprises an element for receiving (56) the laser beam (34) disposed in the housing (48) and configured to be cooled, said element of reception (56) of the laser beam (34) being configured to absorb a residual part of the laser beam (34) after its passage through the parts to be welded (2). Welding machine (1) according to any one of claims 1 to 9, in which the laser beam (34) has a power of between 1200W and 3000W. Welding machine (1) according to any one of claims 1 to 10, wherein the drive wheels (26) are configured to move the welding machine (1) along the parts to be welded at a speed of between 2m /min and 6m/min. Welding machine (1) according to any one of claims 1 to 11, in which the drive wheels (26) each extend in a intersecting plane relative to a plane of the parts to be welded (2), the plane secant of at least one of the drive wheels (26) being distinct from a plane perpendicular to the plane of the parts to be welded (2). Welding machine (1) according to any one of claims 1 to 12 in combination with claim 6, comprising at least two pairs of drive wheels (26) which are arranged on either side of the housing (48) of the welding device (30) in a longitudinal direction (L) of the welding machine (1).