JP2016032830A - Joining method of plate-shaped member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining method by which stable joining quality can be obtained even in a condition which is difficult in joining by resistance spot welding.SOLUTION: This joining method joins a plurality of plate-shaped members 1, 2 by sequentially applying arc welding to a plurality of joining-scheduled regions 3 to 5 while moving a welding electrode 11 along plane directions of a plurality of the laminated plate-shaped members 1, 2. The welding electrode 11 is made to meander on the respective joining-scheduled regions 3 to 5, and the welding electrode 11 is moved so that an intrusion position P1 to the joining-scheduled regions 3 to 5 differs from a retreat position P2 from above the joining-scheduled regions 3 to 5.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for joining plate-like members.

  For example, a steel plate is usually used for a plate-like member constituting an automobile body. In addition, as a means for joining a plurality of superposed steel plates, resistance spot welding that can obtain stable joining quality at a lower cost than other joining means tends to be used.

  By the way, with recent demands for fuel efficiency reduction for automobiles, demands for weight reduction of vehicle bodies are increasing. In addition, in order to improve the safety and operating stability (or riding comfort) of the occupant, there is an increasing demand for increasing the rigidity of the vehicle body, particularly the cabin portion. Since the bonding strength at the door opening of the cabin greatly contributes to the rigidity of the cabin, it is necessary to improve the bonding strength of the door opening.

  In this way, in order to achieve both weight reduction and high rigidity, a high-tensile steel plate such as high tension is adopted for the steel plate for the vehicle body to reduce the plate thickness and increase the number of welds per member. Has begun to be considered. However, the high-tensile steel plate has poor weldability as compared with the conventional steel plate, resulting in a problem that the bonding strength is weak. Also, with resistance spot welding, it is difficult to form a good joint (such as nuggets) when the plate thickness ratio is large, or when the resistance spot welding pitch is reduced, adjacent welding points However, there is a problem that the number of welds cannot be increased as expected because a diversion occurs in the joint portion already formed.

  In order to cope with the above-mentioned problem, for example, introduction of arc spot welding using arc welding has been studied (see, for example, Patent Document 1).

JP 2003-275870 A

  However, arc spot welding is performed by moving the welding torch over the base material joining area and then generating an arc with the base material. When applied, it is necessary to generate an arc each time. Considering that there are many arc failures at the beginning of arc discharge, we want to reduce the number of arc discharge starts as much as possible. However, if arcs were generated as many as the number of joints as described above, the rate of arc generation failure There was a problem that increased. In particular, in order to obtain a penetration of a corresponding size, there is a problem that since the current value needs to be increased by that amount, the stability at the start of the arc is more likely to be lacking.

  In view of the above circumstances, the problem to be solved by the present invention is to provide a joining method capable of obtaining stable joining quality even under conditions difficult to achieve by resistance spot welding.

  The solution to the above problem is achieved by the method for joining plate members according to the present invention. That is, this joining method joins a plurality of plate-shaped members by sequentially performing arc welding on a plurality of planned joining regions while moving the welding electrodes along the planar direction of the plurality of stacked plate-shaped members. The welding electrode is meandered on each planned joining area, and the welding electrode is moved so that the entry position on the joining planned area and the exit position from the planned joining area are different. Attached.

  Thus, by performing arc welding while meandering the welding electrode on the planned welding region, it is possible to obtain a large size penetration in the plane direction while preventing excessive heating of the planned welding region. Therefore, it is possible to form a good joint in the planned welding area. Of course, the generation of slag can be suppressed because an appropriate current value is sufficient. In addition, since the welding electrode is moved so that the entry position and the exit position on the planned joining area are different, the trajectory from one planned joining area to another joining planned area adjacent thereto. The welding electrode can be moved continuously (in a so-called one-stroke mode) without interruption. With such a movement mode, the arc generated between the base material (plate-like member) can be sequentially moved onto adjacent joining scheduled areas, and thus arc discharge is started each time. It is possible to stably generate an arc between the plate-like members in each of the planned joining regions. Therefore, stable bonding quality can be obtained in any bonding scheduled region. In addition, since it is not necessary to stop the welding electrode each time and keep the current flowing until the arc is stabilized, arc welding can be performed in a short time and with reduced energy costs.

  In the joining method according to the present invention, the current value while the welding electrodes move between adjacent joining regions is set to a magnitude that does not cause melting into the plate member. Also good.

  By adjusting the current value in this way, when moving the region other than the planned joining region, the base material due to excessive heating is maintained while maintaining the arc generated between the base material and the plate-like member. It is possible to save energy costs by preventing penetration into the water. Therefore, it is possible to form a stable quality joint in a plurality of planned areas without waste.

  Further, in the joining method according to the present invention, the trajectory when the welding electrode meanders on the planned joining region may be set to a shape that does not intersect, and more preferably, the welding electrode is the joining planned region. The melting part formed while meandering above may be formed at a position that does not overlap with each other in a state where the plate-like member is viewed in plan.

  Thus, by making the movement locus on the joining region of the welding electrode into a shape having no intersection, the mode of melting into the plate-like member generated around the movement locus is stabilized. That is, at the location where the movement trajectory of the welding electrode intersects on the planned joining region, double penetration into the plate-like member will be attempted, but at the second penetration trial, the already formed melted part will be new. Inhibits the penetration of molten metal (when current is weak). If the current value at the time of arc generation is increased, it is possible to re-melt the existing melted part, but in this case, there is a new possibility that it will burn out. In this regard, as in the present invention, by preventing the movement trajectories of the welding electrodes on the planned joining region from crossing each other, it is possible to prevent a situation where excessive penetration that inhibits or leads to melting is caused. Can be prevented. Therefore, it is possible to stabilize the penetration mode into the plate member in the planned joining region and obtain more stable joining quality.

  As described above, according to the present invention, it is possible to provide a joining method capable of obtaining stable joining quality even under conditions difficult to achieve by resistance spot welding.

It is principal part sectional drawing for demonstrating the joining method of the plate-shaped member which concerns on one Embodiment of this invention. FIG. 2 is a plan view of a principal part showing a movement trajectory of a welding electrode when the plate-like member shown in FIG. 1 is viewed from the direction of arrow A. It is a graph showing the time fluctuation of the electric current value in the joining method concerning one embodiment of the present invention. It is a BB sectional view of a joined object formed with a joining method concerning one embodiment of the present invention. It is principal part sectional drawing for demonstrating the joining method which concerns on other embodiment of this invention.

    Hereinafter, the joining method of the plate-shaped member which concerns on one Embodiment of this invention is demonstrated based on drawing. In the following description, in order to facilitate understanding of the description, the positional relationship of the members is described using the vertical direction in the drawings, but this direction indicates the workpiece (plate-shaped member) during actual joining. Of course, it does not limit the heavens and heavens.

  FIG.1 and FIG.2 is principal part sectional drawing for demonstrating the joining method of the plate-shaped member which concerns on one Embodiment of this invention. As shown in these figures, in this joining method, arc welding is sequentially performed on a plurality of planned joining regions while moving the welding electrode 11 along the planar direction of the two plate-like members 1 and 2 that are overlapped. In this method, the two plate-like members 1 and 2 are joined. In the present embodiment, a case where arc welding is performed from only the first plate-like member 1 located on the upper side (only one side) will be described below as an example.

  A welding torch 10 used for this arc welding is connected to an arc welding machine and attached to the tip of a robot arm such as an articulated robot (both are not shown). Then, as shown in FIG. 1, the welding torch 10 is continuously moved without being stopped by the robot arm, and a plurality of planned joining regions (three joining planned regions 3 to 5 in this embodiment) 1, an arc is generated between the welding electrode 11 held at the tip of the welding torch 10 and the first plate-like member 1 serving as a base material, so that the first plate-like member 1 is melted. .

  Here, the welding electrode 11 draws the movement locus | trajectory which meanders on each joining plan area | region 3-5. In this embodiment, as shown in FIG. 2, while starting arc discharge from the predetermined position on the 1st plate-shaped member 1 which is not the joining plan area | regions 3-5, the planar direction of the 1st plate-shaped member 1 Start moving to. Then, the arc enters the first joining scheduled region 3 while maintaining the arc discharge, and starts meandering. In the illustrated example, the welding electrode 11 enters the joining planned area 3, and then bends to the left once, and then bends to the right, and finally turns to the left to join the joining area 3. A moving trajectory to exit (so-called substantially S-shaped trajectory) is drawn. The welding electrode 11 stops at a predetermined position outside the planned joining area 5 after the same movement trajectory is drawn in the other joining planned areas 4 and 5. Thus, the intrusion position P1 and the exit position P2 from above the planned joining regions 3 to 5 are passed while passing as much as possible on the presumed joining planned regions 3 to 5. The welding electrodes 11 are sequentially moved on the respective planned joining regions 3 to 5 in a different manner.

  During this time, the energization conditions are set so that the arc generated between the welding electrode 11 and the first plate-like member 1 serving as the base material is maintained. Specifically, as shown in FIG. 3, when the welding electrode 11 is not on the joining scheduled regions 3 to 5, at least an arc generated between the first plate member 1 and the welding electrode 11 can be maintained. The energization conditions such as the current value should be set to a certain level, and more preferably, the size should be set to such a level that the first plate-like member 1 does not melt. In addition, when the welding electrode 11 is present on each of the planned joining regions 3 to 5, the current value is set to such a magnitude that a predetermined depth of penetration into the first and second plate-like members 1 and 2 can be obtained. .

  As described above, by setting the movement trajectory of the welding electrode 11 and the energization conditions and performing arc welding, the melted portion 6 is formed in each of the planned joining regions 3 to 5, and from the first plate-like member 1. The penetration part 7 of the depth which reaches the 2nd plate-shaped member 2 is formed (FIG. 4). In this case, the fusion | melting part 6 formed in each joining plan area | regions 3-5 makes the shape meandered according to the movement locus | trajectory (FIG. 2) of the welding electrode 11. FIG. Moreover, in this embodiment, the fusion | melting part 6 formed in the joining plan area | regions 3-5 is formed in the position which does not mutually overlap in the state which planarly viewed the 1st plate-shaped member 1. FIG. Thereby, the penetration part 7 of the uniform depth as much as possible without the variation in penetration depth is formed in the joining plan area | regions 3-5 (FIG. 4).

  In this way, in the present invention, arc welding is performed while meandering the welding electrode 11 on the planned welding regions 3 to 5, so that excessive heating to each of the planned welding regions 3 to 5 is prevented in the plane direction. The melted part 6 (FIG. 2) having a size can be obtained. At this time, the penetration portion 7 having an appropriate depth can be obtained by heating and melting under an appropriate energization condition. Therefore, it becomes possible to obtain a desired joint strength by forming good joints in the planned welding regions 3 to 5. Further, by moving the welding electrode so that the entry position and the exit position on the planned joining area are different from each other, it is adjacent to this from the one planned joining area (the leftmost planned joining area 3 in FIG. 2). The welding electrode 11 can be moved continuously (in a so-called one-stroke mode) onto the other planned joining region (scheduled joining region 4 in the middle in FIG. 2) without interruption of the trajectory. If it is such a movement mode, since it can move to the adjacent joining scheduled regions 3 to 5 while maintaining the arc generated between the base material (first plate-like member 1), An arc can be stably generated between the plate-like members 1 in each of the planned joining regions 3 to 5 without starting arc discharge each time. Therefore, stable bonding quality can be obtained in any of the planned bonding regions 3 to 5. In addition, since it is not necessary to stop the welding electrode each time and keep the current flowing until the arc is stabilized, arc welding can be performed in a short time and with reduced energy costs.

  Moreover, in this embodiment, the welding locus | trajectory at the time of the welding electrode 11 meandering on the joining plan area | regions 3-5 makes a shape without an intersection, and the fusion | melting part 6 formed by this in the joining plan area | regions 3-5 is formed. The plate-like member 1 is formed in a position that does not overlap each other in a plan view. Thereby, the situation where the new fusion | melting part 6 overlaps on the fusion | melting part 6 already formed in the 1st plate-shaped member 1 can be avoided reliably. Therefore, it is possible to eliminate the variation in the penetration depth due to the formation of the molten portion 6 overlappingly, and to form the penetration portion 7 having a stable size (depth), thereby obtaining a stable bonding quality. Is possible.

  Although one embodiment of the present invention has been described above, the joining method according to the present invention is not limited to the above-described exemplary form, and it is needless to say that any form can be adopted within the scope of the present invention.

  For example, in the said embodiment, although the form which meanders in a substantially S shape was illustrated as a movement locus | trajectory of the welding electrode 11 on the joining plan areas 3-5, it does not necessarily need to be limited to this form. Arbitrary forms can be applied as long as a melted portion can be uniformly formed in the planned joining region according to the shape of the planned joining region to be set. For example, although illustration is omitted, it is also possible to take a movement locus that meanders in a substantially M shape by slightly shifting the entry position P1 and the exit position P2.

  Moreover, in the said embodiment, in order to shorten moving time (working time), the locus | trajectory in which the welding electrode 11 moves linearly between the adjacent joining plan areas 3-5 is illustrated, but of course, in this aspect. It does not need to be limited, and may be moved in a curve according to the three-dimensional shape of the plate-like member to be welded, for example, as necessary.

  Moreover, in the said embodiment, although the case where the arc welding was performed only from the side of one plate-shaped member (1st plate-shaped member 1) and the junction part was formed was demonstrated, the several plate-shaped member overlap | superposed, for example It is also possible to perform arc welding in the above-described manner from both the front and back sides. FIG. 5 shows the cross-sectional shape of the joint formed in this case. As shown in FIG. 5, arc welding is performed not only from the first plate-like member 1 side but also from the second plate-like member 2 side in the above-described meandering mode and energization conditions. The melted portion 8 is also formed in the planned joining regions 3 to 5 from the second plate-like member 2 side. Further, a penetration portion 7 having a depth from the second plate member 2 to the first plate member 1 is formed. Thereby, since both the melted parts 7 and 9 are connected at the center in the thickness direction of the plate-like members 1 and 2, it becomes possible to form a stronger joint part.

  In the above description, the case where two plate members are joined is taken as an example, but the present invention is of course applicable to the case where three or more plate members are joined.

  Further, in the above description, the case where the plate thicknesses of the plurality of plate-like members are equal is given as an example, but of course, the present invention can also be suitably applied to the case of joining a plurality of plate-like members having different plate thickness ratios. .

  Moreover, although the case where various joints are formed only by arc welding is illustrated in the above description, it is of course possible to use in combination with other joining means (resistance spot welding, conventionally known arc welding, etc.).

  Moreover, the plate-shaped member in the above description should just be plate-shaped (shape which can be overlap | superposed) at least in the joining plan area | region, and the shape of another site | part does not ask | require. Further, the application target is also arbitrary, and the present invention can be applied to other structural body components as well as vehicle body components.

DESCRIPTION OF SYMBOLS 1, 2 Plate-shaped members 3-5 Joining area | region 6,8 Melting part 7,9 Penetration part 10 Torch 11 for welding

Claims (3)

A method for joining the plurality of plate-like members by sequentially performing arc welding on a plurality of joining scheduled regions while moving the welding electrodes along the planar direction of the plurality of plate-like members superimposed,
A plate-like member that causes the welding electrode to meander on each of the planned joining regions, and moves the welding electrode so that an intrusion position on the planned joining region and a withdrawal position from the planned joining region are different. Joining method.   The joining of the plate-shaped member according to claim 1, wherein the current value during the movement of the welding electrode between the adjacent joining regions adjacent to each other is set to a magnitude that does not cause penetration into the plate-shaped member. Method.   The joining method of the plate-shaped member according to claim 1, wherein a trajectory when the welding electrode meanders on the joining scheduled region is set to a shape without crossing.

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