JPH0780048B2 - Welding distortion prevention method for thin metal plates - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a welding distortion preventing method for a thin metal plate, and more particularly to a welding distortion preventing method for a thin metal plate suitable for butt welding or fillet welding of the thin metal plate.

[Prior art]

In recent years, many structures such as high-speed boats, fishing boats, and vehicles have been provided with a structure formed by welding a thin metal plate such as an aluminum alloy. However, in the assembling process of such a thin metal plate, welding distortion is usually likely to occur. For example, in plate joint welding (butt welding) of a large plate material such as a side plate of a ship using a thin metal plate, as shown in FIG. 7, the plate materials 1 and 2 cause complicated wavy distortion due to buckling deformation. It may end up. One reason for this is considered to be that when butt continuous welding of ordinary thin metal plates is performed, the welded part thereof contracts (longitudinal contraction) in the welding line direction as shown in FIG. And this contraction causes the plate material
A force that tends to contract vertically also works around the 1 and 2 welds,
Since the plate materials 1 and 2 are thin plates, buckling deformation easily occurs, and as a result, the state shown in Fig. 8 is assumed. Further, as shown in FIG. 9, when the T-joint is formed from the plate member 3 and the elongated member such as the flat bar 4 by the fillet welding, in addition to the above-described buckling deformation strain of the plate member 3, the welding head The plate member 3 faces the flat bar 4 side around the portion 5, and so-called angular distortion is likely to occur. These wavy distortions and angular distortions not only deteriorate the appearance quality, but also increase the wave resistance during navigation when applied as a hull structure, etc. To give,
It is required to make this as small as possible. Therefore, conventionally, as a measure against the distortion caused by the welding as described above, for example, during welding, the plate materials 1 and 2 or the plate material 3 are mechanically constrained. Local heating and quenching
In the fillet welding of the T-joint for removing the strain, a means such as heating the back surface 3b side of the plate material 3 at the same time corresponding to the fillet welding (Japanese Patent Laid-Open No. 58-179765) is adopted. .

[Problems to be Solved by the Invention]

However, the above conventional means have the following disadvantages. That is, in the above means, the number of steps and labor are required, the cost becomes extremely high, and the skill of the work is required. Further, in the above means, although it is possible to surely expect the effect of suppressing the strain generation, it is difficult to remove the strain to a nearly complete state, and there is a problem that a certain amount of strain has to remain. By the way, the applicant of the present invention has previously invented an effective prevention method for the above-mentioned angular distortion strain that occurs during fillet welding when forming a T-joint, and has already applied for it (Japanese Patent Application No. 2-75965). No. "Strain prevention welding method and structural panel manufacturing equipment").
In this strain prevention welding method, the flat bar 4 is erected substantially vertically on the one surface side of the plate material 3 by fillet welding as described above to form a T joint, and the back surface side of the welded portion of the plate material 3 is welded. It is characterized by heating prior to. In this welding method, reverse distortion (angular deformation strain that bends in the direction opposite to the flat bar 4) occurs in the plate material 3 due to preceding heating, and thereafter, the plate material 3 undergoes angular deformation on the flat bar 4 side due to welding, and thus the reverse strain occurs. It utilizes the effect that is offset to some extent. At that time, by performing welding of the portion where the reverse distortion occurs before the cooling of the preceding heating portion is completed, the inverse distortion caused by the preceding heating is almost completely restored by the angular deformation to the flat bar 4 side during welding. As a result, the plate member 3 can be made to have almost no residual angular deformation strain. However, even in the above method, when the plate material 3 undergoes the buckling deformation as shown in FIG. 9 together with the angular deformation strain, the angular deformation strain can be effectively prevented, but the corrugated seat is formed. It was quite difficult to prevent the occurrence of flexural deformation strain. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a strain prevention welding method for a thin metal plate that can effectively prevent buckling deformation strain that occurs during thin plate welding, with a simple means. It is what

[Means for Solving the Problems]

The method for preventing welding distortion of a thin metal plate according to claim 1 of the present invention is, when performing continuous butt welding of the thin metal plate, at least one of a front surface and a back surface of the thin metal plate to be welded and an edge parallel to a welding line. It is characterized in that the part is heated linearly. Further, according to the present invention, the method for preventing welding distortion of a thin metal plate according to the second aspect of the present invention is such that an elongated member made of a thin metal plate is erected substantially vertically by fillet welding on one surface side of a plate material made of a thin metal plate.
In forming a joint, while heating the back surface side along the welding line to perform the fillet welding of the plate material prior to the welding, at least one of the front surface and the back surface of the plate material and the welding line It is characterized in that the parallel edges are heated linearly. According to a third aspect of the present invention, there is provided a method for preventing welding distortion of a thin metal plate, wherein a plurality of elongated members made of the thin metal plate are provided on one surface side of the plate made of the thin metal plate so as to be substantially vertical and parallel to each other. When standing up by welding to form a multi-row T-joint, the back surface side along each welding line in the plate material along which the fillet welding is to be performed is heated prior to the welding, and the front and back surfaces of the plate material are also heated. At least one of which is parallel to the welding line and the central portion between the elongated members of the plate material is linearly heated.

[Action]

The wavy distortion due to buckling deformation of the sheet material in the butt welding of thin metal plates is considered to be caused by the shrinkage of the welded portion in the welding line direction. It is considered that this contraction causes a force to longitudinally contract the plate around the welded part as well, causing buckling deformation in the peripheral part because the plate material is a thin plate. Therefore, by linearly heating the edges of at least one of the front surface and the back surface of the plate material that are parallel to the welding line, vertical contraction force similar to that of the welded part occurs at those plate ends, which causes the longitudinal contraction force of the welded part. Is relaxed and buckling deformation is prevented. In the case of forming a T-joint by fillet-welding a plate member and an elongated member, the back surface of the plate member along the welding line is heated prior to the welding so that the plate member is reverse-strained (elongated member). (An angular deformation strain that bends in the opposite direction) occurs. After that, since the plate material is angularly deformed on the elongated member side by welding, the reverse strain is offset to some extent. At that time, before the cooling of the preheated portion is not completed, by welding the portion where the reverse strain occurs, the reverse strain is almost completely restored, and the plate material becomes substantially flat. Therefore, when the T-joint is formed, both of the preceding heating of the back surface of the welding line and the above-described linear heating of the edge portion of the plate material are performed, so that the angular deformation strain and the buckling deformation strain of the plate material are obtained. Both of these can be prevented, and an extremely highly accurate T-joint can be formed. Furthermore, the T-joint is a multi-row T in which many elongated members are arranged.
In the case of a joint, in addition to the above means, it is effective to continuously heat the central portion between the elongated members of the plate material.

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an embodiment of a welding distortion preventing method for a thin metal plate according to claim 1 of the present invention. Claim 1 of the present invention
A method for preventing welding distortion of a thin metal plate according to, when performing continuous butt welding of the thin metal plate, linearly heats an edge portion that is at least one of the front surface and the back surface of the thin metal plate to be welded and is parallel to the welding line. It is a thing. In FIG. 1, reference numerals 1 and 2 in the drawing denote plate materials (metal thin plates) to be joined to each other by butt welding. In this embodiment, both of the plate materials 1 and 2 are made of an aluminum alloy. Therefore, in this case, the butt welding is performed by MIG welding. What is indicated by reference numeral 10 is MIG
A torch, reference numeral 5, is a weld bead portion of a portion already welded by the MIG torch 10. Further, the heating when linearly heating both edge portions 1c, 2c which are parallel to the welding line in both plate materials 1, 2 is performed by TIG arc in this case,
Reference numeral 20 (20A, 20B) is a TIG torch. In order to join the plates 1 and 2 by butt welding, as shown in FIG. 1, the ends to be welded of the plates 1 and 2 are brought into contact with each other, and the abutted portions are continuously connected by the MIG torch 10. Weld it. Then, at that time, the welding lines, that is, the portion welded by the MIG torch 10 (welding bead portion 5) or the both plate members 1 and 2 parallel to the portion to be welded
The edges 1c and 2c of the TIG emitted by the TIG torch 20 are respectively
Continuously heated linearly with an arc. The continuous welding by the MIG torch 10 and the edge heating by the TIG torch 20 may move each of the torches 10, 20 with respect to the plate materials 1, 2.
On the contrary, the torches 10 and 20 may be fixed and the plate members 1 and 2 may be moved. Since the TIG torch 20 is intended to be heated by the TIG arc, no filler material (welding rod) is used. Further, regarding the positional relationship of both TIG torches 20A and 20B with respect to the welding direction of the MIG torch 10, the MIG torch 10
The position may be in line with, or may be a position preceding or behind the MIG torch 10. In the illustrated example, both TIG torches 20A and 20B are arranged in a line with the MIG torch 10. The degree of heating when heating the edge portions 1c and 2c is not particularly limited, but usually the very surface layer portion of the plate materials 1 and 2 (0.1 mm
However, it may be adjusted appropriately according to the plate thickness of the plate materials 1 and 2, etc. Further, the plate thickness of the plate materials 1 and 2 is usually 10 mm or less, but preferably 1
~ 5mm is good. This is because when the plate thickness is 10 mm or more, buckling deformation itself does not easily occur due to the large plate thickness, and the problem of the present invention does not occur. According to the above welding method, butt welding can be performed without causing buckling deformation strain, that is, wavy strain, in the plate materials 1 and 2 as shown in FIG. 7. This is because the edge portions 1c, 2c parallel to the welding line are linearly heated as described above, thereby causing vertical contraction similar to that of the weld portion at the edge portions 1c, 2c, and thereby the longitudinal contraction force of the weld portion. Is alleviated and buckling deformation is prevented.
Therefore, in the illustrated example, the heating of the edge portions 1c and 2c is on the same surface as welding, that is, the surface 1 of each of the plate materials 1 and 2.
Although the example is performed from the side of a and 2a, the heating of the edge portions 1c and 2c may be performed from the side of the back surfaces 1b and 2b of the plate materials 1 and 2. In this embodiment, the type of the MIG welding is not particularly limited, a normal spray transfer type, thin wire,
Various methods and power supply methods such as pulse, inverter, and thyristor can be used. Further, the type of TIG welding machine used for heating the plate ends 1c and 2c is not particularly limited, and iron core type, thyristor, inverter and the like can be used. Further, in the above-mentioned embodiment, the butt welding of the plate materials 1 and 2 is performed by MIG welding, but this welding means is not limited to MIG, and carbon dioxide arc welding, which is generally performed conventionally, MAG welding, etc. The welding method may be used. Although the example using the TIG arc as the heating means has been shown, the heating means according to the present invention is not limited to this, and for example, a gas burner, a plasma arc, a laser, an electron beam or other high energy heat source may be used. It is possible. In the above method, as the material of the plate materials 1 and 2, other than the above aluminum alloy, mild steel and the like can be suitably applied. Further, the "edge" of the plate material referred to in the present invention is a portion from the end edge of the plate material to the inner side (the side closer to the welding line) within the range of three times the beam width generated by the high energy heat source. It includes. Next, examples of the above method will be described below. Example-1 According to the above method, continuous butt welding of plate materials 1 and 2 was carried out under the following conditions as shown in FIG.・ Sheet 1: JIS A5083-0 Aluminum, size 300mm * 1000mm, thickness 4mm. ・ Sheet 2: Same as Sheet 1.・ Welding condition: MIG current 200A. Voltage 21V. Welding speed 1600mm / min. ・ Heating condition: Heating element TIG current 150A. Voltage 20V. Speed 1600mm / min. 1c edge part under the same conditions as above. Table 1 below shows a comparison with the case where the heating of 2c is not performed. The amount of deformation H ₁ in the table indicates the height (average value) of the waves generated at the edges 1c and 2c as shown in FIG. As is clear from Table 1 above, as described above, the edge portions 1c, 2
When heating of c is performed, buckling deformation strain hardly occurs in the plate materials 1 and 2. Further, compared with the case where the edge heating is not performed, the welding method according to the present invention is far more suitable for the plate material.
It can be seen that the distortion of 1 and 2 is small. Also, even if the heating of the edge portions 1c, 2c is performed prior to welding,
Although it has already been explained that the welding may be carried out after the welding, according to the experiments of the applicant, there is no time restriction when the welding is advanced or delayed. That is, the limits on the leading and trailing distances for welding in edge heating are infinite. Next, FIGS. 3 and 4 show an embodiment of a method for preventing welding distortion of a thin metal plate according to claim 2 of the present invention. A method for preventing welding distortion of a thin metal plate according to a second aspect of the present invention comprises forming a T-joint by vertically standing a slender member made of a thin metal plate on one surface of a plate made of the thin metal plate by fillet welding. , While heating the back surface side along the welding line to perform the fillet welding of the plate material prior to the welding, and at least one of the front surface and the back surface of the plate material and an edge portion parallel to the welding line. It is heated linearly. FIGS. 3 and 4 respectively show the plate material 3 by the above method.
9A and 9B are a front view and a side view showing a state in which a T-joint 6 is created by fillet-welding a flat bar (elongate member) 4. In this embodiment, both the plate member 3 and the flat bar 4 are made of aluminum alloy,
Therefore, in this case, the fillet welding is performed by MIG welding. Reference numeral 10 (10A, 10B) is a MIG torch. Further, the heating of the back surface side of the welded portion and the heating of the edge portions 3c, 3c 'of the plate material 3 performed prior to this fillet welding are both performed by TIG.
It is supposed to be performed by an arc, and TIG torches are shown by reference numerals 21 and 20 (20A, 20B), respectively. To make the T-joint 6 as described above, the upper surface 3a of the plate member 3
Then, the flat bar 4 to be erected is installed so as not to create a gap and is fixed by means such as temporary attachment. afterwards,
As shown in FIG. 4, the TIG torch 21 is the MIG torch 10A, 10B.
In order to always keep a predetermined distance with respect to (leading the TIG arc from the TIG torch 21 to irradiate the back side of the portion to be welded by the MIG torch 10), the plate material 3
And the flat bar 4 is moved with respect to each torch 10, 20, 21. At that time, the edges 3c, 3c 'of the plate materials 3 which are parallel to the welding line are continuously heated by the TIG torches 20A, 20B, respectively. Again, in the example shown, the TIG torch 2 for edge heating
Although the positions 0A and 20B correspond to the MIG torch 10, the heating of the edge portions 3c and 3c 'may be performed before or after the welding. It is also possible to move the torches 10, 20, 21 while the plate member 3 and the flat bar 4 are fixed. Further, the heating of the edge portions 3c, 3c 'may be performed from either side of the upper surface 3a and the lower surface 3b of the plate material 3. Also, TIG
The degree of advance heating of the back surface of the welded portion by the torch 21 is not particularly limited, but for the same reason as described above, it may be enough to melt the surface layer portion of the plate material 3, and in practice, it may be appropriately adjusted according to the plate thickness of the plate material 3 Good. According to the above method, the plate material 3 does not cause angular deformation strain as shown in FIG. 9, and the buckling deformation strain of the plate material 3 can be removed. The pre-heating of the welded portion can prevent the angular distortion of the plate material 3 because the pre-heating causes reverse distortion (angular deformation distortion of bending in the opposite direction of the flat bar 4) in the plate material 3, and then the MIG torch 10 This is because the plate 3 is angularly deformed on the side of the flat bar 4 by welding, and at that time, by performing the welding of the portion in which the reverse distortion is generated before the cooling of the preceding heating portion is completed, the heat balance between the front and back is obtained. It seems that the reverse distortion is restored by the above. Also, the buckling deformation strain is prevented as in the previous embodiment.
This is because the plate material 3 is prevented from contracting vertically by heating the edge portions 3c and 3c '. Therefore, according to the above method, it is possible to realize the T joint 6 with extremely high accuracy by using the metal thin plate. In the above, it is preferable that the preceding position at the time of preceding heating by the TIG torch 21 is 10 to 1000 mm with respect to the welding position. If the pre-heating position is less than 10 mm, you can expect only the same strain suppression effect as the same-position heating (the method of heating the back surface of the weld at the same time as welding), and if it is 1000 mm or more, the pre-heating part is completely cooled during welding. This is because the heat balance between the front and back of the welded portion (the amount of heat input to the front and back of the welded portion is the same or the difference is small) cannot be sufficiently obtained. Furthermore, in order to obtain these effects more sufficiently, it is desirable that the preceding heating position is 50 to 500 mm. Experimental Example-2 According to the above method, the T-joint 6 was formed by the plate member 3 and the flat bar 4 as shown in FIGS. 3 and 4 under the following conditions.
It was created.・ Plate 3: JIS A5083-0 aluminum material, dimensions 300mm * 500mm, thickness 4mm. ・ Flat bar 4: JIS A5083-0 aluminum material, dimensions 60mm * 500mm, thickness 5mm. ・ Welding condition: MIG current 180-220A . Voltage 20 to 23V. Welding speed 1600m / min. ・ Preceding heating: Heating element TIG torch current 150A. Voltage 20V. Speed 1600mm / min. Preceding position 200mm. ・ Edge heating condition: Same as preheating. The same position as the weld. The results of the above experiment are shown in Table 2 below in comparison with the case where neither the preceding heating of the lower surface of the welded portion nor the heating of the edge portions 3c and 3c 'is performed under the same conditions. The buckling deformation amount H ₁ in the table is the height (average value) of the waves generated at the edges 3c and 3c ′ as shown in FIG. 5, and the angular deformation amount H ₂ is one as shown in the figure. The edge portion 3c is a dimension (average value) that is separated from the line 1 extended by connecting the other edge portion 3c 'to the welded portion. As is clear from Table 2 above, the edges 3c, 3
It can be seen that both the buckling deformation strain and the angular deformation strain of the plate member 3 are extremely small when the preheating of c ′ and the welded portion is performed. Next, FIG. 6 shows an embodiment of a method for preventing welding distortion of a thin metal plate according to claim 3 of the present invention. According to a third aspect of the present invention, there is provided a method for preventing welding distortion of a thin metal plate, in which a plurality of elongated members made of the thin metal plate are erected by fillet welding on one surface side of the thin metal plate so as to be substantially vertical and parallel to each other. When forming a multi-row T-joint, while heating the back surface side along each welding line of the plate material along which the fillet welding is performed prior to the welding, at least one of the front surface and the back surface of the plate material In addition, the edge portion parallel to the welding line and the central portion between the elongated members of the plate material are linearly heated. FIG. 6 shows a state in which a plurality of flat bars (elongated members) 4, 4, ... It is a front view. The plate material 3 and the flat bars 4, 4, ... Are made of aluminum alloy, and in this case also, the fillet welding is performed by MIG welding. Code 10 (10A ~
10F) is a MIG torch. In addition, heating of the back side of the welded portion, which is performed prior to fillet welding, and the edge portions 3c, 3 of the plate member 3
CIG heating and heating between flat bars 4 and 4 are all TIG
It is supposed to be performed by an arc, and reference numeral 21 (21A, 21B, 21
C) is a TIG torch for preheating on the back of the weld, code 20 (20
A, 20B) is a TIG torch for heating the edges 3c, 3c ', code 22 (22A
22D) is a TIG torch for heating between the flat bars 4. In the production of the multi-row T-joint 7 as described above, the fillet welding by the MIG torch 10 corresponding to each flat bar 4, 4, ..., The heating by the TIG torch 21 preceding the fillet welding, and the edge portion 3
Heating in parallel with the welding lines of c and 3c 'is performed in accordance with the method of making the T-joint 6 shown in the above-mentioned embodiment. The heating of the edge portions 3c, 3c 'may be performed before or after the welding, as in the above two embodiments, and may be performed from either side of the upper surface 3a and the lower surface 3b of the plate member 3. . However, it is desirable to heat the central portion between the flat bars 4, 4, ... In the plate material 3 from both sides of the upper surface 3a and the lower surface 3b of the plate material 3 as shown in the drawing. This is because when only one side surface of the plate material 3 is linearly heated at the central position between the flat bars 4, the effect of restraining the peripheral portion is exerted at the time of thermal expansion, and contracted angular deformation may occur on the heating surface side. Because there is. On the other hand, at the edge portion, the effect of the above-mentioned restraint of the peripheral portion does not work, and even if the one-sided heating is performed, the heating surface does not contract and the angular deformation does not occur. According to the above method, it is possible to form the multi-row T-joint 7 in which neither buckling deformation strain nor angular deformation strain of the plate material 3 occurs substantially. Experimental Example-3 According to the above method, a multi-row T-joint 7 was prepared under the following conditions by the plate material 3 and the flat bars 4, 4, ... As shown in FIG. -Plate material 3: JIS A5083-0 aluminum material, dimensions 1500mm * 3000mm, thickness 4mm.-Flat bar 4: JIS A5083-0 aluminum material, dimensions 60mm * 3000mm, thickness 5mm.-Flat bar 4 arrangement interval: plate 250mm from the end and 500mm pitch. -Welding conditions: MIG current 180-220A. Voltage 20-23V. Welding speed 1600mm / min.-Preceding heating: Heating element TIG torch current 150A. Voltage 20V. Speed 1600mm / min. Leading position 200mm forward.・ Edge heating condition: Same as pre-heating. The same position as the weld. The results of the above experiment, the flat bar 4,4,
Table 3 below shows a comparison with the case where heating is not performed between. The amount of buckling deformation H ₁ and the amount of angular deformation H ₂ in the table
Is measured according to the case of the previous example. As is clear from Table 3 above, it is understood that the multi-row T-joint 7 with extremely small strain can be obtained by the above method.

【The invention's effect】

As described above, according to the invention of claim 1, it is possible to surely realize the butt welding of the metal thin plates with extremely little distortion by a simple means. And thereby, the quality of the structure comprised by the butt welding of a thin metal plate can be improved. According to the invention of claim 2, the thin metal plate is used for T
In forming the joint, it is possible to realize a highly accurate T-joint in which both the angular deformation strain and the buckling deformation strain of the plate material are extremely small. Furthermore, according to the invention of claim 3, even a multi-row T-joint with extremely little strain can be formed reliably and easily. Therefore, by applying it to a structure such as a panel having a plurality of rows of vertical aggregates, it is possible to reduce the number of construction steps and the construction period of a ship or the like, and to significantly reduce the cost.

[Brief description of drawings]

1 and 2 show an embodiment of the invention according to claim 1 of the present invention. FIG. 1 is a perspective view showing a state of butt welding of plate materials according to this embodiment, and FIG. FIG. 3 is a perspective view showing a plate material welded for explaining a strain measuring procedure of a metal thin plate welded by an embodiment, and FIGS. 3 to 5 are embodiments of the invention according to claim 2 of the present invention. FIG. 3 is a front view showing a state of making a T-joint according to this embodiment, FIG. 4 is a side view of FIG. 3, and FIG. 5 is a strain measurement procedure of a metal thin plate welded according to this embodiment. FIG. 6 is a perspective view showing a welded T-joint for the purpose of explaining FIG. 6, and FIG. 6 is a front view showing a production state of a multi-row T-joint according to this embodiment in one embodiment of the invention according to claim 3 of the present invention FIGS. 7 to 9 are explanatory views of the prior art. FIG. 7 is a perspective view of a butt-welded plate material, and FIG. Figure is a plan view of a butt-welded sheet material, FIG. 9 is a perspective view of a T-piece created by fillet welding. 1 ... plate, 1c ... edge, 2 ... plate, 2c ... edge, 3
…… Plate material, 3b …… Back surface, 3c, c ′ …… Plate end, 4 …… Flat bar (slender member), 6 …… T joint, 7 …… Multi-row T joint. (The above reference numerals 1, 2, 3 and 4 are thin metal plates.)

Claims (3)

[Claims] 1. When performing continuous butt welding of a thin metal plate, at least one of the front surface and the back surface of the thin metal plate to be welded, and an edge portion parallel to the welding line is linearly heated. Welding distortion prevention method for thin plates. 2. An elongate member made of a thin metal plate is erected substantially vertically on the one surface side of a plate made of a thin metal plate by fillet welding to form T.
In forming a joint, while heating the back surface side along the welding line to perform the fillet welding of the plate material prior to the welding, at least one of the front surface and the back surface of the plate material and the welding line A method for preventing welding distortion of a thin metal plate, which comprises heating parallel edges linearly. 3. A multi-row T-joint is formed by erected a plurality of elongated members made of a metal thin plate on one surface side of a plate made of a metal thin plate by fillet welding so as to be substantially vertical and parallel to each other. While heating the back surface side along each welding line to be subjected to the fillet welding in the plate material prior to the welding, at least one of the front surface and the back surface of the plate material and an edge portion parallel to the welding line and A method for preventing welding distortion of a thin metal plate, which comprises heating the intermediate portion between the elongated members of the plate material linearly.