JP6307029B2 - Base metal welding method - Google Patents

Description

  The present invention relates to a base material welding method for welding two base materials.

  Patent Document 1 describes a railway vehicle structure in which a waist plate shape and a window portion shape made of a hollow extruded shape are abutted, and the waist plate shape and the window shape are welded by arc welding in a lateral orientation. Yes. In this railway vehicle structure, the waist plate shape member has a male projection piece that protrudes from the corners of the inner plate, the outer plate, and the width plate, and has a step that forms a groove surface on the outer surface. Has a female protruding piece that protrudes from the corners of the inner plate, the outer plate, and the width plate and has a groove surface on the tip surface. And the groove | channel which can be arc-welded by a sideways attitude | position is comprised by fitting the front-end | tip part from the level | step difference (groove surface) of a male protrusion piece inside a female protrusion piece. By performing arc welding on the groove, the waist plate shape and the window shape are joined.

JP-A-10-175542

  The groove formed by the waist plate shape member and the window portion shape member of the railway vehicle structure described in Patent Document 1 is capable of arc welding in a lateral orientation, and is a male protrusion that constitutes the bottom portion of the groove. The tip portion is in close contact with the female protrusion from the inside. Thus, when arc welding is performed with a groove that opens only in one horizontal direction, bubbles in the molten metal can escape only from the opening. Bubbles move in the molten metal by arc or buoyancy, and those that have reached the opening can be released to the atmosphere. However, since the molten metal solidifies in a relatively short time, the molten metal solidifies before the bubbles existing on the bottom side of the groove or once flowing to the bottom side reach the opening. As a result, many blow holes are formed in the welded portion. Also, when arc welding is performed in an upward posture, the groove opens downward, so that many blow holes are formed in the welded portion as in the horizontal posture welding. Thus, when many blow holes (defects) are formed in the welded portion, there arises a problem that the mechanical performance of the joint is lowered.

  Accordingly, an object of the present invention is to provide a base metal welding method in which bubbles that become blowholes are less likely to remain when arc welding is performed in a lateral orientation or an upward orientation.

The base metal welding method of the present invention is a groove forming step in which an end surface of a base material faces the end surface of another base material so that arc welding can be performed in a lateral orientation or an upward orientation, and a groove is formed therebetween. And a welding process for welding the two base materials by filling the groove with molten metal by the arc welding, and the two base materials are hollow extruded shapes that can be fitted to each other are composed of wood, in the groove forming step, backing constituting the forming the groove by fitting the two base material, the bottom of and the groove over the two preform A gap is formed between the plate portion and at least one base material to allow the groove to communicate with the atmosphere from the bottom side.

According to this, bubbles in the molten metal generated in the welding process can be released to the atmosphere from the bottom side of the groove through the gap. For this reason, it becomes difficult to form a blow hole in the weld. Moreover, it becomes possible to form a groove easily.

  In the present invention, in the groove forming step, it is possible to perform the arc welding in the lateral orientation, and the two base materials and the gap so as to extend upward from the bottom of the groove. It is preferable to arrange the backing plate portion. Thereby, it is possible to effectively release the bubbles in the molten metal to the atmosphere through the gap.

  Moreover, in this invention, it is preferable that the said backing board part is integrally formed in said one base material. This makes it easy to adjust the gap.

  In the present invention, it is preferable that a groove constituting the gap is formed in the backing plate portion. Thereby, it becomes easy to form a clearance gap easily.

According to the base metal welding method of the present invention, bubbles in the molten metal generated in the welding process can be released to the atmosphere from the bottom side of the groove through a gap. For this reason, it becomes difficult to form a blow hole in the weld. Moreover, it becomes possible to form a groove easily.

It is a schematic perspective view which shows the vehicle body structure of the rail vehicle manufactured by the base material welding method which is one Embodiment of this invention. It is principal part sectional drawing when the side structure and connection shape member in the right side in FIG. 1 are fitted. It is a situation figure which shows the condition of the bubble in a molten metal when a side structure and a connection shape are welded. It is a modification of the preform | base_material welding method of this invention, and is principal part sectional drawing which shows the condition where the clearance gap is formed between the backing plate part of another member, and two outer surface boards. It is another modification of the preform | base_material welding method of this invention, and is principal part sectional drawing which shows the condition where the groove | channel is formed so that arc welding is possible in an upward attitude | position.

  Hereinafter, a vehicle body structure of a railway vehicle manufactured by a base metal welding method according to an embodiment of the present invention will be described with reference to FIG. The vehicle body 1 includes a frame 11 that forms a floor surface, a pair of side structures 12 that form left and right surfaces of the vehicle body 1, a roof structure 13 that forms a roof, and both ends with respect to the longitudinal direction A of the vehicle body 1. It is comprised from a pair of wife structure (not shown) which forms the surface to close.

  At both ends of the frame 11 in the width direction B (direction perpendicular to the longitudinal direction A), connecting shape members 15 having an L-shaped cross-sectional shape are provided. The side structure 12, the roof structure 13, and the connection shape 15 are made of a hollow extruded shape that is long in the longitudinal direction A, and the ends of these shapes are perpendicular to the vertical direction C (the longitudinal direction A and the width direction B). The vehicle body 1 is configured by being welded along the longitudinal direction A in a state of being fitted in the direction). Further, in the vehicle body 1 of the present embodiment, aluminum side structure body 12, roof structure body 13, and connection shape member 15 employ aluminum double-skin structure body materials, but are not particularly limited thereto.

  Then, the welding method of the connection shape 15 and the side structure 12 which comprise the vehicle 1 is demonstrated below, referring FIG.2 and FIG.3. FIG. 2 is a cross-sectional view of the main part when the side structure 12 on the right side in FIG. First, a schematic configuration of the connection shape member (base material) 15 and the side structure (base material) 12 will be described. As shown in FIG. 2, the connecting shape member (base material) 15 and the side structure (base material) 12 are hollow extruded shapes formed by extrusion molding, and the upper end portion and the side structure of the connection shape member 15. 12 is configured to be able to fit in the vertical direction C. The connecting member 15 and the side structure 12 include a plurality of intermediate plates 23, 33, 34 including outer plates 21, 31 arranged on the right side in FIG. 2 and inner plates 22, 32 arranged on the left side in FIG. 2. It is connected by. The intermediate plate 23 is formed at the upper end of the connection shape member 15, and the intermediate plate 33 is formed at the lower end of the side structure 12.

  As shown in FIG. 2, a backing plate portion 25 that protrudes upward from the upper end surface 21 a of the outer surface plate 21 is integrally formed on the connection shape member 15. The upper end surface 21a of the outer surface plate 21 is inclined so as to be positioned downward toward the outer side (right side in FIG. 2). The middle plate 23 is connected to the upper end of the backing plate portion 25. The inner surface plate 22 is formed so as to protrude upward from the middle plate 23, and is inclined so that its upper end surface 22a is positioned downward as it goes inward (left side in FIG. 2).

  As shown in FIG. 2, the side structure 12 is integrally formed with a backing plate portion 35 protruding downward from a corner portion where the inner surface plate 32 and the intermediate plate 33 are connected. The lower end surface 32a of the inner surface plate 32 is inclined so as to be positioned upward as it goes inward. The outer surface plate 31 is formed so as to protrude downward from the middle plate 33, and is inclined so that its lower end surface 31a is positioned upward as it goes outward.

  As shown in FIG. 2, the connecting member 15 and the side structure 12 are arranged such that the end face 21a and the end face 31a are opposed to each other in the up-down direction C, and the end face 21a and the end face 31a are opened between the end faces. The tips 41 and 42 are fitted so that they are formed. Each backing plate portion 25, 35 extends between the connection shape 15 and the side structure 12 inside the outer surface plate 31 and the inner surface plate 22 when the connection shape 15 and the side structure 12 are fitted. The bottoms of the grooves 41 and 42 are formed.

  Grooves 25a and 35a are formed in the backing plate portions 25 and 35 as shown in FIG. The depth of the grooves 25a and 35a in this embodiment is 0.2 mm, but is not limited to this. The groove 25 a extends upward from the bottom of the groove 41 and constitutes a gap S <b> 1 that communicates with the bottom of the groove 41. Further, the groove 25 a extends in the longitudinal direction A and is formed over the entire longitudinal direction A of the connection shape member 15. Thereby, the gap S1 communicates with the atmosphere at both ends in the longitudinal direction A of the groove 25a. For this reason, when the connection shape member 15 and the side structure 12 are fitted together, the bottom of the groove 41 communicates with the atmosphere through the gap S1 formed by the groove 25a. The backing plate portion 25 may have a plurality of air communication holes (not shown) extending in the vertical direction C or the width direction B and spaced apart from each other along the longitudinal direction A. Good. These atmospheric communication holes are respectively connected to intermediate portions in the longitudinal direction A of the groove 25a. By doing so, the gap S1 formed by the groove 25a communicates with the atmosphere even through the atmosphere communication hole.

  The groove 35 a extends downward from the bottom of the groove 42 and constitutes a gap S <b> 2 that communicates with the bottom of the groove 42. The groove 35 a extends in the longitudinal direction A and is formed over the entire longitudinal direction A of the side structure 12. Thus, the gap S2 communicates with the atmosphere at both ends in the longitudinal direction A of the groove 35a. For this reason, when the connection shape member 15 and the side structure 12 are fitted together, the bottom of the groove 42 communicates with the atmosphere through the gap S2 formed by the groove 35a. Even if the backing plate portion 35 is formed with a plurality of air communication holes (not shown) extending in the vertical direction C or the width direction B and spaced apart from each other along the longitudinal direction A. Good. These atmospheric communication holes are respectively connected to intermediate portions in the longitudinal direction A of the groove 35a. By doing so, the gap S2 constituted by the groove 35a communicates with the atmosphere even through the atmosphere communication hole.

  By welding the side structure 12 to such a connection shape member 15, the side structure 12 and the underframe 11 are coupled. In the present embodiment, the connection profile 15 and the side structure 12 are MIG welded, but the present invention is not limited to this, and arc welding other than MIG welding may be used. When performing MIG welding, first, as shown in FIG. 2, the connection shape 15 and the side structure 12 are fitted, and the connection shape 15 and the side structure 12 are fixed by a jig (not shown). At this time, the grooves 41 and 42 are formed between the end surfaces 21a and 31a of the outer plates 21 and 31 and between the end surfaces 22a and 32a of the inner plates 22 and 32 (groove forming step). The grooves 41 and 42 formed at this time both extend in the longitudinal direction A and open in the horizontal direction. For this reason, the connection shape member 15, the side structure 12, and the welding are performed in a lateral orientation. The grooves 41 and 42 are degreased in advance as a pretreatment.

  Next, as shown in FIG. 3A, MIG welding is performed on the groove 41. As welding conditions in the present embodiment, the welding current is 206 A, the voltage is 23.4 V, the torch elevation angle is 15 °, and the advance angle is 15 °. When the MIG welding is performed, a shield gas (inert gas) is supplied from the front end surface of the nozzle 51 and around the welding wire 52 in the direction of arrow G, that is, toward the groove 41. As a result, the shield gas is filled in the groove 41 and the vicinity thereof, and a shield gas atmosphere is created. The shield gas is also filled into the gap S1 formed by the groove 25a via the groove 41. Then, an arc is generated between the welding wire 52 and the groove 41, and the groove 41 is filled with molten metal (welding process).

  At this time, as shown in FIG. 3 (a), a plurality of bubbles E are formed in the molten metal due to deposits on the groove 41 portion (base metal) and the surface of the welding wire and hydrogen, shield gas, ambient air, and the like inside. Occur. The molten metal flows as indicated by an arrow D by the arc flow F in the order of opening of the groove 41 → bottom part → opening. For this reason, the plurality of bubbles E move in the molten metal due to the flow of the molten metal and its own buoyancy.

  Among the plurality of bubbles E, the bubble E1 that has moved to the opening side of the groove 41 and reached the opening escapes to the atmosphere as shown in FIG. Since the molten metal is solidified in a relatively short time, the bubbles E2 existing on the bottom side of the groove 41 cannot reach the opening of the groove 41 and cannot escape from the opening to the atmosphere. However, since the gap S1 communicating with the bottom of the groove 41 is formed by the groove 25a in the backing plate portion 25 in the present embodiment, the bubbles E2 are likely to reach the gap S1 by the arc flow. When the bubble E2 reaches the gap S1, it escapes to the atmosphere via the gap S1. For this reason, there are very few bubbles in the molten metal, and when the molten metal is solidified, it is difficult to form a blow hole in the welded portion 16 (see FIG. 3C).

  Further, the groove 25 a extends upward from the bottom of the groove 41. That is, the gap S <b> 1 extends upward from the bottom of the groove 41. Since the bubble E2 also generates buoyancy in addition to the arc flow, the bubble E2 tends to gather above the bottom of the groove 41. For this reason, the bubble E2 can be effectively released to the atmosphere via the gap S1.

  Next, MIG welding is performed on the groove 42 (welding process). In this case, it is executed under the same conditions as the welding conditions for the groove 41. In welding to the groove 42 as well, when a plurality of bubbles are generated in the molten metal, most of them escape to the atmosphere from the gap S2 formed by the opening of the groove 42 and the groove 35a. The groove 35 a extends downward from the bottom of the groove 42. In other words, the gap S <b> 2 also extends downward from the bottom of the groove 42. For this reason, although it is difficult for the bubbles remaining above the bottom of the groove 42 to escape to the atmosphere, the bubbles E2 in the vicinity of the bottom move near the bottom by the arc flow, and therefore easily reach the gap S2. For this reason, most of the bubbles remaining in the vicinity of the bottom of the groove 42 can be released to the atmosphere. For this reason, there are very few bubbles in the molten metal in the groove 42, and when the molten metal is solidified, it is difficult to form a blow hole in the welded portion 16.

  When the welding with the connection shape 15 and the side structure 12 is completed, as shown in FIG. 3C, the surface of the welded portion 16 (the opening side of the groove 41) and rises from the surfaces of the outer plates 21, 31. The excess portion is cut away. It should be noted that the surplus portions raised from the surfaces of the inner surface plates 22 and 32 on the surface of the welded portion (opening side of the groove 42) are also cut off. In this finishing step, the blowhole formed on the surface side of the welded portion 16 is removed.

  As a result of investigating the number of blow holes in the weld length of 500 mm in the welded portion 16 of the above-described grooves 41 and 42, about 10 to 20 blowholes are confirmed in the welded portion 16 of the groove 41, and the groove. About 100 blowholes were confirmed at 42 welds. Further, in the state where the gap S1 is provided and the end surfaces 21a and 31a are separated from each other with a horizontal plane, about 40 blowholes in a weld length of 500 mm in a welded portion welded under the same welding conditions. Was confirmed. In addition, in the weld length of 500 mm in the welded portion welded to the groove 41 under the same welding conditions without closely attaching the backing plate portion 25 in which the groove 25a is formed to the outer surface plate 31 and providing the gap S1. About 200 blowholes were confirmed. As a result, by forming the grooves 41 and 42 and the gap that allows the groove to communicate with the atmosphere from the bottom side, bubbles in the molten metal can be easily released to the atmosphere, and the number of blow holes is greatly reduced. I understand.

  As described above, in the welding method of the present embodiment, bubbles in the molten metal generated in the welding process can be released to the atmosphere from the bottom side of the grooves 41 and 42 through the gaps S1 and S2. Become. For this reason, it becomes difficult to form a blow hole in the welded portion 16.

  Further, since the gap S1 extends upward from the bottom of the groove 41, the bubbles in the molten metal can be effectively released to the atmosphere via the gap S1.

  Further, the grooves 41 and 42 are formed by fitting the connecting shape member 15 and the side structure 12 together. Thereby, the grooves 41 and 42 can be easily formed.

  Further, the backing plate portion 25 is integrally formed with the connecting shape member 15, and the backing plate portion 35 is integrally formed with the side structure 12. Thus, the gaps S1 and S2 can be formed only by fitting the connecting shape member 15 and the side structure 12, and the gaps S1 and S2 can be easily adjusted.

  In the present embodiment, the backing plate portions 25 and 35 are formed integrally with the connection shape member 15 and the side structure 12, but may be separate members. In this modified example, as shown in FIG. 4, in the groove forming step, the backing plate portion 125 having the groove 125 a is formed into two outer surface plates 121 and 131 having substantially the same configuration as the outer surface plates 21 and 31. It arrange | positions so that it may extend, and the bottom part of the groove 141 is comprised. At this time, the upper and lower ends of the backing plate 125 are removed by a jig (not shown) so that the groove 125a extends in the vertical direction C and forms a gap S3 that communicates with the bottom of the groove 141. The face plates 121 and 131 are held in contact with each other. The groove 141 is formed between the upper end surface 121 a of the outer surface plate 121 and the lower end surface 131 a of the outer surface plate 131. The gap S3 communicates with the atmosphere. Even in this case, even when arc welding is performed on the groove 141 in the lateral orientation, the same effect as in the above-described embodiment can be obtained. Furthermore, in the present modification, the gap S3 extends vertically from the bottom of the groove 141. For this reason, bubbles in the molten metal existing at the bottom of the groove 141 can be effectively released to the atmosphere. The backing plate portion 125 may be separated from any one of the outer surface plates 121 and 131. It is preferable to separate from the outer surface plate 131 located above. By so doing, the gap S3 extends upward from the bottom of the groove 141, and the same effect as in the above-described embodiment can be obtained.

  As another modification, the grooves 25a and 35a may not be formed in the backing plate portions 25 and 35. In this case, when the connecting shape member 15 and the side structure 12 are fitted together, the lower end portion of the backing plate portion 35 and the inner surface plate 22 are provided between the upper end portion of the backing plate portion 25 and the outer surface plate 31. For example, a gap may be formed on the bottom side of the grooves 41 and 42 with a 0.2 mm liner plate interposed therebetween. A plurality of liner plates may be arranged apart from each other in the longitudinal direction A, or a single liner plate that is long in the longitudinal direction A may be employed. Further, the thickness of the liner plate may be other than 0.2 mm and may be appropriately selected. Also in this case, since the bottoms of the grooves 41 and 42 communicate with the gap and the gap communicates with the atmosphere, the same effect as described above can be obtained.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in the above-described embodiment, arc welding is performed in a horizontal posture, but may be performed in an upward posture. That is, as shown in FIG. 5, in the groove forming step, even if the outer surface plates 221 and 231 having substantially the same configuration as the outer surface plates 21 and 31 are formed so that the groove 241 faces obliquely downward, A gap S4 is formed by a groove 225a formed in the backing plate 225 that extends over the two outer plates 221 and 231 and forms the bottom (upper side) of the groove 241. For this reason, even if arc welding is performed on the groove 241, bubbles in the molten metal escape to the atmosphere through the gap S <b> 4 as in the above-described embodiment. As a result, it becomes difficult to form a blow hole in the weld.

In the above-described embodiment, in the groove forming step, the grooves 41 and 42 formed by the connecting shape member 15 and the side structure 12 have formed the gaps S1 and S2 that communicate with each other on the bottom side. What is necessary is just to form in the position which communicates by the groove | channel between the some hollow extrusion shape members long in the longitudinal direction A which comprises the side structure 12, and a bottom part side. In short, it is possible to perform arc welding in a sideways or upward orientation, and when the end surface of a base material faces the end surface of another base material and a groove is formed between the two base materials, What is necessary is just to form the clearance gap which connects a groove | channel and a bottom part side, and communicates with air | atmosphere between the backing board part which comprises the bottom part of a groove | channel, and at least one of two base materials. By doing this, it is possible to obtain the same effect as the above-described embodiment .

  In the above-described embodiment, the upper end surface 21 a of the outer surface plate 21 constituting the groove 41 and the lower end surface 31 a of the outer surface plate 31, and the upper end surface 22 a and the inner surface plate 32 of the inner surface plate 22 constituting the groove 42 are provided. The lower end surface 32a is inclined with respect to the groove shape, but may be parallel to each other.

12 Side structure (base material)
15 Connection profile (base material)
21a, 22a, 121a Upper end surface (end surface)
25, 35, 125, 225 Backing plate portion 25a, 35a, 225a Groove 31a, 32a, 131a Lower end surface (end surface)
41, 42, 141, 241 groove S1, S2, S3, S4 gap

Claims (4)

A groove forming step in which the end face of the base material faces the end face of another base material so that arc welding can be performed in a lateral orientation or an upward orientation, and a groove is formed between them.
A base material welding method including a welding step of welding the two base materials by filling the groove with molten metal by the arc welding,
The two base materials are composed of hollow extruded shapes that can be fitted to each other,
In the groove forming step, the groove is formed by fitting the two base materials, and a backing plate portion and at least one base that spans the two base materials and constitutes the bottom of the groove. A base material welding method, wherein a gap is formed between the groove and the material to allow the groove to communicate with the atmosphere from the bottom side.   In the groove forming step, the two base materials and the backing plate can be used so that the arc welding can be performed in the lateral posture, and the gap extends upward from the bottom of the groove. The base metal welding method according to claim 1, wherein the portion is arranged. The base material welding method according to claim 1, wherein the backing plate portion is formed integrally with the one base material. The base metal welding method according to any one of claims 1 to 3 , wherein a groove constituting the gap is formed in the backing plate portion.

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