JP2015199110A - Laser weld method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effective technique capable of surely jointing weld objects by laser weld, even when there is a gap between the metal weld objects.SOLUTION: The laser weld method of the invention is configured so that: in a state that a plate W2 being a second weld object is disposed on a lower side of a plate W1 being a first weld object, with a gap 102, laser beam Lb is radiated from an upper position of the plate W1 toward a weld scheduled area 101 over the plate W1 and the plate W2 sandwiching the gap 102, for jointing the plate W1 and the plate W2.

Description

  The present invention relates to a laser welding technique for joining metal plate materials together by laser welding.

  Conventionally, various techniques for overlapping metal plate materials and joining them by laser welding have been proposed. In Patent Document 1, in the laser welding method, another metal plate is placed on the upper surface of the metal plate on the laser irradiation side among the two metal plates to be joined to each other, and the other metal is also melted together at the time of laser irradiation. The technology is disclosed. Thereby, even when the gap between the two metal plates is large, it is possible to ensure sufficient molten metal to fill the gap. In Patent Document 2, in a method of lap joint welding metal thin plates having gaps of irregular dimensions, laser welding is performed twice, and laser irradiation is defocused during the first laser welding. A technique for reducing the variation in the plate gap dimension before the second laser welding is disclosed. Patent Documents 3 and 4 each disclose a technique for relieving stress concentration by laminating fillet joints in a state where there is no gap between them and smoothing the shape of the joint portion.

JP-A-6-297171 JP 2010-23047 A JP 2004-148333 A Japanese Utility Model Publication No. 60-60175

(Problems to be solved by the invention)

  By the way, the laser welding disclosed in Patent Documents 1 to 4 is advantageous because the energy density is higher than that of arc welding and precise welding can be performed at high speed and with low distortion. On the other hand, for the purpose of increasing the processing accuracy during welding and for the purpose of ensuring the escape path of plating vapor generated during welding in a plate material such as a galvanized steel plate, it is common to positively provide a gap between the plate materials. . In this case, if the gap is too large, the molten metal for filling the gap is insufficient, and it becomes difficult to perform fillet joint welding as disclosed in Patent Documents 3 and 4 by laser welding. Therefore, when performing such fillet joint welding, it is necessary to positively provide a gap between the plate materials despite the need to originally utilize the advantages of laser welding, Instead of laser welding, arc welding had to be used.

  The present invention has been made in view of the above points, and one of its purposes is to reliably join the welding objects by laser welding even when there is a gap between the metal welding objects. It is to provide effective technology.

(Means for solving the problem)
In order to achieve the above object, the laser welding method according to the present invention is a method for joining metal objects to be welded together by laser welding. In this laser welding method, the first welding object is placed in a state where the second welding object is disposed below the first welding object with a gap therebetween, and the first welding object is sandwiched from above the first welding object. The first welding object and the second welding object are joined by irradiating the laser beam toward the welding planned area over both the welding object and the second welding object. In this case, a weld joint is formed in which the molten metal of each of the first welding object and the second welding object enters the gap and solidifies to close the gap. As a result, a gap is formed between the first welding object and the second welding object by using laser welding, which has a higher energy density than arc welding and enables high-speed, low distortion and precise welding. Even when it is necessary to provide, it is possible to reliably join the welding objects by laser welding.

  In the laser welding method described above, the welded joint that joins the first welded object and the second welded object is formed in the planned welding region, and the first opposed surface that faces the gap and the first opposed surface The laser welding conditions are set so that the angle formed by the second low-strength welding object having a relatively lower strength between the first welding object and the second welding object and the second facing surface facing the gap is an obtuse angle. It is preferable to set. In this case, laser welding conditions typically include laser irradiation intensity of laser light, welding speed, welding position (laser light irradiation position), and the like. Since the angle formed by the first facing surface and the second facing surface becomes an obtuse angle, stress concentration generated at the boundary portion between the weld joint and the low-strength welding object having a lower strength is alleviated, so that the boundary portion The fatigue strength can be improved.

  In the above laser welding method, the first welding object and the second welding object are both metal plate materials that are stacked in the thickness direction with a gap therebetween, and the plate gap dimension of the gap in the planned welding region. It is preferable to set the laser welding conditions based on at least one of information on the position of the plate side surface of the first welding object. In this case, for example, the laser irradiation intensity of the laser light is changed based on the plate gap dimension of the gap, or the welding position (laser light irradiation position) is changed based on the position of the plate side surface of the first welding object. can do. Thereby, it becomes possible to perform laser welding under optimum conditions according to the plate gap size of the gap and the position and shape of the plate side surface of the first welding object.

  In the above laser welding method, laser light is irradiated in an oblique direction intersecting the plate thickness direction from a position higher than the first welding object, and the heat input amount per unit area of the first welding object is the second. It is preferable to control the beam profile of the laser beam so as to exceed the heat input per unit area of the welding object. When laser light is irradiated obliquely from a position above the first welding object, the heat input distribution is such that a molten metal amount corresponding to the plate gap dimension can be secured for the first welding object. Applied to the second welding object, the welding object is melted to such an extent that a bridge is formed with the molten metal of the first welding object, and the welding object itself is perforated. A heat input distribution is applied so as not to cause the heat input. Thereby, the amount of heat input required for each of the first welding object and the second welding object can be appropriately supplied.

  In the laser welding method described above, the plate side surface of the first welding object is an opening formed in a plate end surface of the first welding object or a penetrating shape in the plate thickness direction of the first welding object. The inner wall surface of the opening is preferable. When the plate side surface of the first welding object is the plate end surface, the laser welding conditions are set using the position information of the plate end surface included in the planned welding region. On the other hand, when the plate side surface of the first welding object is the inner wall surface of the opening, the laser welding conditions are set using the position information of the inner wall surface of the opening included in the planned welding area. Thereby, the above laser welding process can be effectively applied to at least two welding modes.

  As described above, according to the present invention, even when there is a gap between metal welding objects, the welding objects can be reliably joined by laser welding.

FIG. 1 is a system configuration diagram of a laser welding system 100 according to the present embodiment. FIG. 2 is a diagram showing a flowchart of the laser welding process. FIG. 3 is a diagram schematically illustrating a process corresponding to steps S101 to S103 in FIG. FIG. 4 is a diagram schematically showing a process corresponding to step S104 in FIG. FIG. 5 is a diagram showing an evaluation result of the laser welding process of the present embodiment. FIG. 6 is a diagram showing the characteristics of the welded joint B of the present embodiment together with a comparative example. FIG. 7 is a diagram showing an evaluation result of the laser welding process of the present embodiment. FIG. 8 is a diagram showing a beam profile BP of the laser beam Lb in the laser welding process of the present embodiment. FIG. 9 is a diagram for explaining a method for realizing the beam profile BP shown in FIG. FIG. 10 is a diagram showing a modification of the form shown in FIG. FIG. 11 is a diagram illustrating a first welding mode. FIG. 12 is a diagram showing a second welding mode.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the laser welding system 100 of the present embodiment includes a first metal plate W1 (upper metal plate located on the laser irradiation side) and a second plate W2 (upper plate). And a lower metal plate located on the opposite side of the laser irradiation side) to each other by laser welding. In this case, the two plate members W1 and W2 extend on a plane defined by the first direction X and the second direction Y, and are overlapped and joined to each other in the third direction Z which is the plate thickness direction. The first plate material W1 and the second plate material W2 here correspond to the “first welding object (metal plate material)” and the “second welding object (metal plate material)” of the present invention, respectively.

  In the present embodiment, both the first plate material W1 and the second plate material W2 are made of galvanized steel plates. For this reason, in order to ensure the escape path of the plating vapor generated at the time of laser welding, the first plate member W1 and the second plate member W2 are in a state where the second plate member W2 is stacked below the first plate member W1. A gap 102 having a predetermined plate gap dimension d is provided therebetween. In this case, if the plate gap dimension d of the gap 102 becomes too large, poor welding is likely to occur. Therefore, management of the plate gap dimension d of the gap 102 is important. Therefore, the laser welding system 100 of the present embodiment fulfills a function of improving the welding quality for laser welding while managing the plate gap dimension d.

  The laser welding system 100 includes a laser displacement meter 110, a laser oscillator 120, a laser welding head 130, and a control device 140. This laser welding system 100 is used in a laser welding process for joining the first plate member W1 and the second plate member W2 to each other by laser welding.

  The laser displacement meter 110 includes information on the planned welding region 101 before laser welding (the plate gap dimension d of the gap 102 between the first plate member W1 and the second plate member W2, and the plate end surface W1b of the first plate member W1. It functions as a measuring instrument for measuring the position (hereinafter also referred to as “plate end surface position Pa”). The plate end surface W1b of the first plate member W1 is also a plate side surface of the first plate member W1 extending in a direction intersecting with the upper surface W1a of the first plate member W1. The laser displacement meter 110 is configured by using a known sensor that receives, with an image sensor (semiconductor element), reflected light obtained by reflecting a laser beam La from a light source on a measurement object. In this case, the laser displacement meter 110 can accurately measure the plate gap dimension d and the plate end surface position Pa by a linear trace in the first direction X in FIG. The laser displacement meter 110 is electrically connected to the control device 140, and measurement information D1 indicating the plate gap dimension d and the positional deviation of the first plate material W1 is transmitted to the control device 140.

  Laser oscillator 120 is a known device that performs the function of generating a laser. The laser beam Lb generated by the laser oscillator 120 is output from the laser welding head 130 through a laser transmission fiber 121 as an amplification medium. The laser oscillator 120 constitutes a substantial laser welding apparatus for irradiating the laser beam Lb together with the laser welding head 130. The laser welding head 130 is typically configured using a known galvano scanner that scans the laser light using one or more mirrors. This laser welding head 130 is in a state where the first plate material W1 and the second plate material W2 are overlapped, and a desired welding planned region 101 over both the first plate material W1 and the second plate material W2 with the gap 102 interposed therebetween. The laser beam Lb is irradiated in an oblique direction intersecting the plate thickness direction from a position higher than the first plate material W1 toward the surface.

  The control device 140 outputs command signals D2 and D3 to the laser oscillator 120 and the laser welding head 130, respectively, based on the measurement information D1 transmitted from the laser displacement meter 110. In this case, the laser oscillator 120 is controlled based on the command signal D2, and the laser welding head 130 is controlled based on the command signal D3. For this purpose, the control device 140 includes a signal input unit for inputting a signal, a signal output unit for outputting a signal, a storage unit for storing measurement information, laser welding conditions, and the like. An arithmetic processing unit that performs arithmetic processing based on the stored information is provided.

  2 to 12 are referred to for the laser welding process by the laser welding system 100 having the above configuration.

  According to step S101 in FIG. 2, the plate gap dimension d of the gap 102 and the plate end face position Pa of the first plate material W1 are measured by the laser displacement meter 110. According to step S102, the control device 140 sets laser welding conditions based on the measurement result (measurement information D1 in FIG. 1) measured in step S101. Specifically, it is determined whether or not it is necessary to correct preset laser welding conditions. If correction of the laser welding conditions is necessary (Yes in step S102), the process proceeds to step S104 after performing the welding condition correction processing in step S103.

  In the correction process of step S103, the control device 140 determines the optimum laser welding conditions (laser irradiation intensity (laser output) of the laser beam Lb, laser welding speed), welding position (laser beam) according to the measurement result of step S101. Lb irradiation position), laser trajectory (laser scanning shape), etc.) are derived, and the current laser welding conditions are corrected to the optimum laser welding conditions and stored.

  On the other hand, when it is not necessary to correct the laser welding conditions (No in step S102), step S103 is skipped and the process proceeds to step S104. In this case, the control device 140 sets the optimum laser welding conditions without correcting the stored current laser welding conditions.

  According to step S104, laser welding for actually joining the first plate material W1 and the second plate material W2 is performed. More specifically, the control device 140 outputs command signals D2 and D3 for realizing the stored optimum laser welding conditions to the laser oscillator 120 and the laser welding head 130, respectively. Accordingly, the laser beam output from the laser welding head 130 under the optimum laser welding conditions is scanned at a predetermined welding speed along the first direction X in FIG. Is done.

  According to the correction process in step S103 in FIG. 2, when the shape accuracy of the plate end surface W1b of the first plate material W1 is low, for example, the shape of the plate end surface W1b changes in the first direction X in FIG. Even if there is a misalignment), it can be dealt with by correcting the laser trajectory according to the measurement result of step S101. Specifically, as shown in FIG. 3, the plate end surface position Pa is a first position (a position indicated by a two-dot chain line) at two locations in the first direction X among the plate end surfaces W1b of the first plate material W1. ) To the second position (the position indicated by the solid line), the laser welding head 130 is controlled accordingly and the irradiation direction of the laser beam Lb is indicated by the first direction (indicated by the two-dot chain line). Direction) to the second direction (the direction indicated by the solid line). Such a change in the irradiation direction of the laser beam Lb may be performed at the time of actual laser welding based on the measurement result of the plate end surface position Pa measured in advance using the laser beam La, or actual laser welding. It may be executed based on the measurement result of the plate end face position Pa that is sometimes performed in parallel using the laser beam La. Thus, even when the shape accuracy of the plate end surface W1b of the first plate material W1 is low, the first plate material W1 is obtained by performing laser welding under optimal conditions according to the position and shape of the plate end surface W1b. And a good bonding state between the second plate member W2 can be realized.

  In the laser welding in step S104 in FIG. 2, as shown in FIG. 4, the laser beam Lb is irradiated from the oblique direction C toward the welding planned region 101, and the laser beam Lb in the first direction X in FIG. It is preferable to adopt a laser irradiation method that moves the lens. In this case, both the first plate material W1 and the second plate material W2 are irradiated with the laser beam Lb with the gap 102 interposed therebetween. More specifically, in the first plate material W1, the laser beam Lb is irradiated to a range from the plate end surface position Pa to the shift position Pb shifted inward in the plate along the second direction Y on the upper surface W1a. In addition, the entire plate end face W1b is irradiated with the laser beam Lb. In the 2nd board | plate material W2, the laser beam Lb is irradiated to the area | region located under the board end surface W1b of the 1st board | plate material W1.

  According to the laser irradiation method described above, the first plate material W1 and the second plate material W2 are joined by the molten metal of each of the first plate material W1 and the second plate material W2 entering the gap 102 and solidifying. A welded joint (also referred to as a “weld bead”) B that closes the gap 102 is formed. Such a welded joint B is also referred to as a “lap fillet joint”. As a result, the gap 102 is provided between the first plate member W1 and the second plate member W2 by using laser welding, which has a higher energy density than arc welding and is capable of high-speed, low distortion and precise welding. Even when necessary, the two plate members W1, W2 can be reliably joined by laser welding. In this case, the 1st board | plate material W1 and the 2nd board | plate material W2 are joined mutually without using another members, such as a filler wire, by the metal melting by the heat input at the time of laser irradiation.

  In the process in which the molten metal of the first plate material W1 enters the gap 102, the molten metal is supported only by the unmelted portion inside the plate from the shift position Pb in the first plate material W1. That is, the molten metal of the first plate material W1 has a form like a so-called “cantilever beam” in which only one side in the second direction Y is supported. According to this form, compared with a lap joint having a form such as a so-called “double-supported beam”, the molten metal of the first plate material W1 tends to have a weak surface tension and tends to sag toward the second plate material W2. For this reason, in the case of a lap fillet joint, since the force which pulls up a molten metal is low compared with the case of a lap joint, there exists an effect that it is effective in sealing the gap | interval 102 reliably. Specifically, reference is made to the evaluation results of FIG.

  According to the evaluation result of FIG. 5, in the case of the lap fillet joint, it is difficult to form a bridge because the molten metal of the first plate member W <b> 1 is supported from only one side, and it is easy to sag to the second plate member W <b> 2 side. . On the other hand, in the case of the lap joint, the molten metal of the first plate member W1 is supported from both sides, so that a bridge can be easily formed and it is difficult to sag to the second plate member W2. As a result, in the case of the lap fillet joint, the maximum allowable gap dimension capable of reliably joining the first plate material W1 and the second plate material W2 is from d1 [mm] to d2 [mm] in the case of the lap joint. It can be raised. As an example, when the maximum allowable gap dimension d1 is 0.3 [mm], the maximum allowable gap dimension d2 can be 0.7 [mm].

  When the second plate member W2 has a lower strength than the first plate member W1 due to a difference in plate thickness or the like, as shown in FIG. 4, the first opposing surface A1 and the second plate member related to the welded joint B are used. The laser welding conditions are preferably set so that the angle θ formed with the second facing surface A2 related to W2 becomes an obtuse angle. In this case, the opposing surface of the welded joint B facing the gap 102 is the first opposing surface A1, and the relatively low strength plate material W2 (low strength welding) of the first plate material W1 and the second plate material W2. The facing surface where the (object) faces the gap 102 is the second facing surface A2. In short, the welded joint B preferably has a cross-sectional shape such that the angle θ formed by the first facing surface A1 and the second facing surface A2 is an obtuse angle.

  In the present embodiment, as shown on the left side of FIG. 6, the weld joint B extends along the first facing surface A1 from the boundary portion (boundary point M) between the first facing surface A1 and the second facing surface A2. The laser welding conditions are preferably set so as to enter the lower strength plate material W2 (low strength welding object) side. In this case, the welded joint B protrudes inward of the plate (a region on the left side in FIG. 6) from the boundary line A3 that passes through the boundary point M and extends in the third direction Z that is the plate thickness direction in the plate material W2. A protrusion Ba (also referred to as “wrapping around”) is provided. According to such a configuration, the first opposing surface A1 and the second opposing surface A2 are subjected to a load action in which loads that are separated from each other in the third direction Z act on the first plate material W1 and the second plate material W2. It is possible to delay the growth of a crack generated at the boundary portion (boundary point M), and as a result, the fatigue strength at the time of loading is increased. On the other hand, in the comparative example shown on the right side of FIG. 6, the weld joint B exists only on the plate outer side (the region on the right side in FIG. 6) than the boundary line A <b> 3 in the plate material W <b> 2. It does not have a site like Ba. In the case of this comparative example, the crack is likely to propagate from the boundary portion (boundary point M) between the first facing surface A1 and the second facing surface A2 when the load is applied, and as a result, as compared with the present embodiment. Thus, the fatigue strength at the time of loading is reduced.

  For this purpose, the cross-sectional shape of the weld joint B can be a convex shape toward the oblique direction C by irradiating the plate materials W1, W2 with the laser light Lb from the oblique direction C. Or you may make it determine the cross-sectional shape of the welded joint B by the method of making wind act on a molten metal and making it flow in the diagonal direction C irrespective of the irradiation direction of the laser beam Lb. When the angle θ is an acute angle, stress tends to concentrate on the boundary portion between the welded joint B and the second plate member W2 on the low strength side, and the fatigue strength of the boundary portion decreases. On the other hand, the boundary portion between the welded joint B and the second plate member W2 can be obtained by making the angle θ an obtuse angle as in the present embodiment and by providing the welded joint B with the protrusion Ba. Since the stress concentration occurring in the region is relaxed, there is an effect that the fatigue strength of the boundary portion can be improved. Specifically, the evaluation results of FIG.

  In the evaluation in FIG. 7, fatigue is obtained by inputting loads in directions away from each other with respect to the first plate member W1 and the second plate member W2 connected via the welded joint B for the three forms C1 to C3. The strength was measured. In the graph in FIG. 7, the vertical axis represents the load S [N] input per time, and the horizontal axis represents the load input number n “times”. In this case, the first plate member W1 is configured to have lower strength than the second plate member W2. The first form C1 is based on laser welding in which the laser beam Lb is irradiated from an oblique direction to the plate materials W1 and W2 so that the angle θ is an obtuse angle. The second form C2 is based on laser welding in which the laser beam Lb is irradiated from the perpendicular direction (vertical direction) to the plate members W1 and W2 so that the angle θ is an acute angle. On the other hand, 3rd form C3 is based on arc welding. When these three forms C1 to C3 are compared, fatigue strength can be improved by using laser welding (first form C1) in which the laser beam Lb is irradiated so that the angle θ becomes an obtuse angle. It was confirmed that there was.

  In the above laser irradiation method (step S104 in FIG. 2), when the laser beam Lb is applied to both the first plate material W1 and the second plate material W2 at a time and in an oblique direction, the laser irradiation position If the deviation occurs, the balance of the amount of molten metal between the first plate material W1 and the second plate material W2 changes significantly, and it is assumed that the laser welding performance is degraded. Therefore, it is preferable to optimize the beam profile (heat input distribution) of the laser beam Lb by controlling the laser oscillator 120 and the laser welding head 130 in order to further improve the laser welding performance. For example, as shown in FIG. 8, the amount of heat input per unit area supplied to the first plate material W1 on the laser irradiation side exceeds the amount of heat input per unit area supplied to the second plate material W2. A simple beam profile BP can be employed.

  More specifically, for the first plate member W1, the gap 102 is set according to the plate gap dimension d of the gap 102 measured by the laser displacement meter 110 and the plate end surface position Pa of the first plate member W1. A heat input distribution is applied to generate a sufficient amount of molten metal to close the first and second plate members W1 and W2 in an appropriate balance. That is, with respect to the first plate material W1, a heat input distribution (for example, a gap 102 for a portion having a relatively large plate gap dimension d) can ensure a molten metal amount corresponding to the plate gap dimension d. A heat input distribution that increases the amount of molten metal dripping is applied. Further, the second plate material W2 has a heat input distribution that melts the plate material to such an extent that a bridge is formed with the molten metal of the first plate material W1 and does not cause perforation in the plate material itself. Applied. According to such a beam profile BP, it is possible to appropriately supply the amount of heat input necessary for each of the first plate material W1 and the second plate material W2.

  Further, by combining this beam profile optimization processing with the correction processing in step S103 in FIG. 2, even if the shape accuracy of the plate end surface W1b of the first plate material W1 is low, the plate end surface W1b By changing the beam profile BP so as to follow the shape, the first plate material W1 and the second plate material W2 can be reliably bonded.

  In order to realize the beam profile BP, for example, a technique as shown in FIG. 9 can be adopted. In the method shown in FIG. 9, the laser beam Lb can be scanned in a circular shape around the predetermined rotation axis in the direction of the arrow R1 while adjusting the laser irradiation intensity, the welding speed, and the like. Alternatively, the laser beam Lb can be scanned in a zigzag manner along the arrow R2 direction while adjusting the laser irradiation intensity, the welding speed, and the like. As a modification of the form shown in FIG. 9, as shown in FIG. 10, the laser light Lb1 (beam profile BP1) irradiated to the first plate material W1 and the laser light Lb2 irradiated to the second plate material W2 are used. Both (beam profile BP2) can also be used. In this case, the two laser beams Lb1 and Lb2 may be emitted from separate light sources, or may be emitted from one light source divided by a splitter (dividing means). Also good.

  The laser welding process described above can be applied at least effectively to two welding modes as shown in FIGS. The first welding mode shown in FIG. 11 corresponds to the laser welding shown in the respective drawings, and the plate end surface (plate side surface) W1b of the first plate material W1 is included in the planned welding region 101. In this case, the laser welding conditions can be set using the position information of the plate end surface W1b. According to laser welding under this condition, a weld joint B is generally formed in a region defined by the plate end surface W1b of the first plate material W1 and the upper surface W2a of the second plate material W2.

  On the other hand, the second welding mode shown in FIG. 12 is an example in which laser welding conditions are set using position information on another plate side surface. In this case, the laser welding conditions can be set using the positional information of the opening inner wall surface W1b 'of the opening 103 formed in a penetrating manner in the plate thickness direction (third direction Z) of the first plate member W1. The opening inner wall surface W1b 'is also the plate side surface of the first plate material W1 like the plate end surface W1b. For this purpose, it is preferable to provide a step of forming an opening in the opening 103 in advance in the first plate member W1. According to laser welding under this condition, a weld joint B ′ is generally formed in a region defined by the opening inner wall surface W1b ′ of the opening 103 of the first plate member W1 and the upper surface W2a of the second plate member W2. The

  The present invention is not limited to the above exemplary embodiment, and various applications and modifications are possible. For example, each of the following embodiments to which the above embodiment is applied can be implemented.

  In the said embodiment, although described about the case where two metal board | plate materials W1, W2 were joined by laser welding, in this invention, at least one of two board | plate materials W1, W2 is welding objects other than a board | plate material, For example, it may be configured as a metal block-shaped member.

  In the said embodiment, although described about the case where the laser welding conditions were set based on the information of both the board clearance dimension d of the clearance gap 102, and the position of the board end surface W1b of the 1st board | plate material W1, in this invention, Laser welding conditions may be set based on information on at least one of the plate gap dimension d of the gap 102 and the position of the plate end surface W1b of the first plate member W1.

  In the above embodiment, the obtuse angle defining target for the welded joint B is described as the second plate member W2 having a lower strength than the first plate member W1, but the first plate member W1 is the second plate member. In the case of W2, the obtuse angle can be defined as the first plate material W1.

  When based on description of said embodiment and various modifications, this invention can take the following each aspects (aspect).

In the present invention,
“A laser welding system for joining metal objects to each other by laser welding,
Welding over both the first welding object and the second welding object with the gap interposed between the first welding object and the second welding object arranged below the first welding object. A laser welding apparatus for irradiating a laser beam from a position above the first welding object toward a planned region;
A control device for controlling the laser welding device;
Including laser welding system. ”(Embodiment 1).

In the present invention,
“The laser welding system according to the first aspect,
In the state where a weld joint for joining the first welding object and the second welding object is formed in the planned welding region, the control device has a first facing where the weld joint faces the gap. The angle formed by the surface and the second opposing surface of the first welding object and the second welding object, the lower strength welding object having a relatively low strength, facing the gap is an obtuse angle. Thus, the laser welding system which sets the laser welding conditions in the said laser welding apparatus. ”(Embodiment 2).

In the present invention,
“The laser welding system according to aspect 1 or 2,
The first welding object and the second welding object are both metal plate materials that are stacked on each other across the gap in the plate thickness direction.
And a measuring machine for measuring at least one of the plate gap dimension of the gap and the position of the plate side surface of the first welding object in the planned welding region,
The said control apparatus is a laser welding system which sets the laser welding conditions in the said laser welding apparatus based on the information measured by the said measuring machine. ”(Embodiment 3).

  DESCRIPTION OF SYMBOLS 100 ... Laser welding system, 101 ... Plane welding area, 102 ... Gap, 103 ... Opening, 110 ... Laser displacement meter, 120 ... Laser oscillator, 121 ... Laser transmission fiber, 130 ... Laser welding head, 140 ... Control device

Claims (5)

A laser welding method for joining metal welding objects by laser welding,
Welding over both the first welding object and the second welding object with the gap interposed between the first welding object and the second welding object arranged below the first welding object. A laser welding method for joining the first welding object and the second welding object by irradiating laser light from a position above the first welding object toward a planned region. The laser welding method according to claim 1,
In a state in which a weld joint for joining the first weld object and the second weld object is formed in the planned welding area, the first opposing surface facing the gap and the first weld joint are formed. Laser welding conditions so that the angle formed by the relatively low-strength low-strength welding object of the welding object and the second welding object with the second facing surface facing the gap is an obtuse angle Set the laser welding method. The laser welding method according to claim 1 or 2,
The first welding object and the second welding object are both metal plate materials that are stacked on each other across the gap in the plate thickness direction.
A laser welding method, wherein a laser welding condition is set based on at least one information of a plate gap dimension of the gap and a position of a plate side surface of the first welding object in the welding planned area. The laser welding method according to claim 3,
The laser beam is irradiated in an oblique direction intersecting the plate thickness direction from a position above the first welding object, and the amount of heat input per unit area of the first welding object is the second welding. A laser welding method for controlling a beam profile of the laser beam so as to exceed an amount of heat input per unit area of an object. The laser welding method according to claim 3 or 4,
The plate side surface of the first welding object is a plate end surface of the first welding object, or an opening inner wall surface of an opening formed in a penetrating shape in the plate thickness direction of the first welding object. There is a laser welding method.

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