JP2011200903A - Welding method of container and refrigeration cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method for achieving welding while securing airtightness, in which removal of spatters after welding is not required and also generation of strain in a weld zone is suppressed.SOLUTION: A container is manufactured by welding using CMT (Cold Metal Transfer) welding. First, wasted welding is implemented by starting CMT welding from a welding starting point 7a which is a position different from a weld zone to be welded, to the weld zone to be welded. After the weld zone to be welded is reached, regular welding is performed by CMT welding on a welding route 6 which is the weld zone to be continuously welded. With the starting point of the regular welding reached, overlapping welding (overlapped weld zone 9) is further continuously performed in the vicinity of the starting point of the regular welding. Thereafter, wasted welding is carried out to a position different from the weld zone to be welded, the position being a welding completion point 8a.

Description

  The present invention relates to a container welding method and a refrigeration cycle apparatus using a container manufactured by using this welding method in a refrigeration cycle, and is particularly suitable for welding a container having a tube seat for connecting pipes.

  The welding method that fuses the base metal and filler metal by using the heat generated by the arc discharge phenomenon is manual welding using a welding rod as the filler material and semi-automatic where the filler material is automatically supplied as a wire Welding is known. As a method using a welding rod, TIG welding using tungsten as an electrode, MAG welding using an inert gas in semi-automatic welding, and MIG welding using only argon as an inert gas are generally used. In these welding methods, the heat used to melt the base metal and filler metal is large, distortion occurs in the welded product, and molten metal particles called spatter are scattered from the weld during the welding operation. Then there was a problem such as adhering to the product. For this reason, in these conventional welding methods, the operation | work which removes distortion after welding, and the washing | cleaning operation | work with an acid in order to remove a sputter | spatter were required. Further, since the heat input is large, there is a problem that distortion occurs, and when a thin plate is welded, the base material is melted and a hole is formed.

  In order to solve these problems, as described in Patent Document 1 and Patent Document 2, Cold Metal Transfer welding (hereinafter referred to as CMT welding) in which the MAG welding and MIG welding are developed. A welding method has been developed. This is a welding method that makes it possible to intermittently generate arcs by devising the supply of wires in MAG welding and MIG welding and repeating the feeding and returning of the wires at high speed.

Special table 2008-531283 gazette Special table 2008-542027 gazette

  According to the CMT welding described above, heat input during welding can be suppressed and distortion of the product can be suppressed. However, since it is a welding method with little melting, it is difficult to ensure the airtightness of the welded portion, and it is difficult to apply it to the welding of a container. In particular, a nest (also called a pinhole in a small hole) may occur at the welding start point, and it cannot be applied to container welding unless this can be prevented.

  For this reason, when manufacturing a container which receives pressure on the inner surface, conventionally, gas welding or arc welding has been used for joining the parts. In these welding methods, the base metal and the welding rod are melted and part of them is alloyed to join the parts together. However, the amount of heat that melts the base metal deeply is used, so the generation of distortion due to this heat is accurate. There was a problem that affected.

  On the other hand, the CMT welding described above is characterized by slightly melting the surface of the welding wire and the base material, and since there is little heat input, distortion after joining can be reduced, welding time is shortened, and improvement in efficiency can be expected. However, since pinholes (nests) are likely to occur at the joint and it is difficult to ensure airtightness, it has been difficult to apply to the manufacture of containers, particularly containers that receive pressure on the inner surface.

  The object of the present invention is to weld a container that can be welded while ensuring airtightness, can eliminate the need for a pickling process for removing spatter after welding, and can suppress the occurrence of distortion in the welded portion, Another object of the present invention is to obtain a refrigeration cycle apparatus using a container manufactured by this welding method in a refrigeration cycle.

  In order to achieve the above object, according to the present invention, in the container welding method, the container is manufactured by welding using CMT (Cold Metal Transfer) welding, and is from a position different from the joint to be welded. Abandon welding is performed by starting CMT welding toward the joint to be welded, and after reaching the joint to be welded, main welding is performed on the joint to be welded continuously by CMT welding. When the welding start point is reached, the overlap around the starting point of the main welding is further continuously performed, and then the welding is performed to a position different from the joint portion to be continuously welded.

  Another feature of the present invention is a container welding method having a barrel and an end plate that closes an end of the barrel, and a tube seat for connecting a pipe to the end plate by welding. The weld for attaching the tube seat to the end plate is manufactured by welding using CMT welding, and CMT welding is started from a position different from the joint to be welded toward the joint to be welded. After reaching the joint to be welded, perform the main welding by CMT welding around the pipe seat, which is the joint to be welded continuously, and reach the starting point of the main welding. The purpose of this is to carry out the overlapping welding in the vicinity of the starting point of the main welding more continuously and then discard the welding to a position different from the joint to be welded continuously.

  Still another feature of the present invention resides in a refrigeration cycle apparatus in which the container produced by any of the above methods is used as an accumulator or a receiver constituting the refrigeration cycle.

  According to the present invention, a container welding method that enables CMT welding that ensures airtightness, eliminates the need for a pickling process for the purpose of removing spatters after welding, and suppresses the occurrence of distortion in the welded portion. In addition, a refrigeration cycle apparatus using a container manufactured using this welding method in a refrigeration cycle can be obtained.

The perspective view which shows the example of the container used for a refrigerating-cycle apparatus. FIG. 2B is an enlarged view of a portion B in FIG. 1 illustrating a conventional method for welding a container. The figure of the weld bead explaining the welding method of FIG. The B section enlarged view of FIG. 1, The figure explaining Example 1 of the welding method of the container of this invention. The figure of the weld bead explaining the welding method in Example 1. FIG. 5A and 5B are diagrams illustrating a second embodiment of the present invention, in which FIG. 4A is a partial plan view of FIG. 4 viewed from above, and FIG. 5B is a front view of FIG. It is a figure explaining the other example in Example 2 of this invention, and is a figure equivalent to the (a) figure of FIG. The figure of the weld bead explaining an example of the welding course in Example 2 of the present invention. The figure of the weld bead explaining the other example of the welding course in Example 2 of the present invention. The figure of the weld bead explaining the further another example of the welding path in Example 2 of the present invention. The figure of the weld bead explaining the further another example of the welding path in Example 2 of the present invention. The figure of the weld bead explaining the further another example of the welding path in Example 2 of the present invention.

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

Prior to describing an embodiment of the present invention, a conventional welding method will be described with reference to FIGS.
FIG. 1 is a view showing a container A such as an accumulator or a receiver used in a refrigeration cycle such as an air conditioner or a refrigeration apparatus. These containers A have a seat 4 for receiving pressure on the inner surface and connecting to the refrigerant pipe. The container A is composed of a body 1, an end plate 2 that closes the upper portion of the body 1, and an end plate 3 that closes the lower portion of the body 1, and the inside is a pressure space in which gas and liquid accumulate. When this container A is used in a refrigeration cycle, it is necessary to connect a refrigerant pipe in order to allow the refrigerant to flow in and out, and the pipe seat 4 for the pipe connection may be required according to the refrigeration safety regulation example related standard. is there.

  FIG. 2 is an enlarged view of part B in FIG. 1, and is an enlarged view showing the end plate 2 on the upper part of the container A and the tube seat 4 provided on the end plate 2. Usually, an iron material is used as the material of the container A, and the pipe 5 connected to the tube seat 4 is a copper material. MAG welding is often used to join iron materials, and MAG welding has a large heat input during welding, and spatter is easily generated and distortion is easily generated in the welded portion. For this reason, a pickling process is required for the purpose of removing spatters after welding, which hinders reduction in the number of manufacturing steps.

  In MAG welding, welding is started from the welding start point 7, the welding path 6 that goes around the connection boundary between the tube seat 4 and the end plate 2 is welded, and then passes through the welding start point 7 to the welding end point 8. Overlap welding. Reference numeral 9 denotes a weld overlap between the welding start point 7 and the welding end point 8.

  FIG. 3 is a view showing the weld bead 6a in the vicinity of the weld overlap portion 9. By providing the weld overlap portion 9, the vicinity of the welding start point 7 is reinforced to ensure the welding strength and airtightness.

  On the other hand, in the present invention, CMT welding is performed instead of the MAG welding, and this CMT welding can suppress the distortion that easily occurs in the conventional MAG welding, but the surface of the base material is only slightly. It does not melt. For this reason, when welding was performed in the same welding path 6 as in the prior art and the weld overlap portion 9 was also welded in the same manner as in the prior art, it was found that although a connection strength could be ensured, a minute nest (pinhole) would occur. .

Therefore, in the embodiment of the present invention, a welding path as shown in FIGS. 4 and 5 is used to prevent the formation of minute nests in the welded portion while employing CMT welding.
That is, in this embodiment, the conventional welding start point 7 shown in FIG. 2 which is a problem in CMT welding is, for example, in the normal direction with respect to the welding path 6 as in the welding start point 7a shown in FIG. Welding is started at an arbitrary fixed distance. By shifting the welding start point in this way, it is necessary to ensure airtightness instead of starting welding directly from a part that needs to be airtightly secured (joint part that should be welded while ensuring airtightness) as in the past. So-called discard welding, in which welding is started from a welding start point 7a other than the part, is performed. As a result, welding can be started from the normal direction with respect to the welding path 6 as described above without setting the welding start point where the welding quality is likely to be unstable as a portion that needs to ensure airtightness. In addition, stable welding is possible when welding (main welding) a joint portion (a portion that needs to be airtight) that should be welded.

  In addition, in the present embodiment, since the joint portion to be originally welded can be heated from the normal direction immediately before welding the portion, it is easy to melt the base material when welding the joint portion to be originally welded. It becomes. Therefore, stable welding can be performed without generating a fine nest by performing CMT welding on a portion that needs to ensure airtightness, and a high-strength container that secures airtightness can be manufactured.

  In addition, since CMT welding is adopted, spatter can be prevented and a pickling process for removing spatter after welding is not required, so that the number of manufacturing steps can be reduced, and further, the welded portion is distorted. There is an effect that can also be prevented.

  Next, as shown in FIG. 4, the joint part to be originally welded is welded once, and as shown in FIGS. 4 and 5, after securing the overlapping welded part 9, a welding wire is further removed from the overlapping welded part 9. , And abandoned welding is carried out to the welding end point 8a in the direction along the surface of the tube seat 4 (normal direction of the welding path 6) (see FIG. 4), and the welding is completed.

  As described above, according to this embodiment, CMT welding is started from the end plate 2 in the normal direction with respect to the weld path 6 of the joint portion to be originally welded around the pipe seat (discard welding). The CMT welding can be stabilized when the CMT welding has progressed to the joint to be originally welded. Also, by discarding the weld from the welding start point to the joint to be originally welded, the joint to be originally welded is preheated, and then the main weld of the joint to be welded is performed, so that the base metal is melted. Can be easily. Further, after performing the main welding by CMT welding around the tube seat, which is a joint to be welded, after securing the overlapping portion of the welding, the CMT welding is performed along the surface of the tube seat 4 which is the normal direction of the welding path. Then, the welding is discarded, and the welding is terminated at the welding end point 8a. Therefore, a thick weld bead can be formed where a pinhole is likely to occur. For these reasons, according to the present embodiment, welding of the joint portion to be originally welded around the tube seat can be performed with CMT welding to ensure confidentiality without generating a pinhole (nest). .

  In the above embodiment, the welding start point 7a and the welding end point 8a are set to the normal direction of the welding path 6. However, if the welding start point 7a and the welding end point 8a are separated from the weld bead width in the welding path 6, the positions are set to the welding start point. 7a or the welding end point 8a, the welding start point 7a or the welding end point 8a may not necessarily be in the normal direction of the welding path 6.

A second embodiment of the container welding method of the present invention will be described with reference to FIGS. In these drawings, the portions denoted by the same reference numerals as those in FIGS. 1 to 5 indicate the same or corresponding portions, and the portions not described are the same as those in the first embodiment.
In the first embodiment, the example in which the welding start point 7a and the welding end point 8a are shifted in the normal direction with respect to the welding path 6 has been described. However, in the second embodiment, the welding path 6 has a direction other than the normal direction. The welding start point 7a and the welding end point 8a are set in the portion.

  First, in the example shown in FIG. 6, a welding start point 7 a of a welding path that is abandoned welding with respect to the welding path 6 around the tube seat, which is a joint portion to be originally welded while ensuring airtightness, is an abbreviation of the welding path 6. The tangential direction is used, and the discard welding is performed in substantially the same direction as the welding direction of the welding path 6 from the welding start point 7a. After that, the original joint portion of the tube seat 4 is welded along the welding path 6, and after making a round of the circumference of the tube seat 4, the overlapping joint portion 9 is secured, and subsequently, continuously to the overlapping joint portion 9. Further, the welding wire is replenished, the welding is discarded along the surface of the end plate 2 in the substantially tangential direction of the welding path 6, and the welding is finished by moving to the welding end point 8a.

  In the example shown in FIG. 7, the welding start point 7 a of the welding path that is abandoned welding with respect to the welding path 6 around the tube seat, which is a joint part that should be originally welded with airtightness, is substantially tangent to the welding path 6. Although the direction is the same as the example shown in FIG. 6, the discard welding is different from the welding start point 7 a in the direction opposite to the welding direction of the welding path 6. Further, the original joint portion of the tube seat 4 is welded along the welding path 6 and the portion to ensure the overlapping joint portion 9 is the same as the example shown in FIG. Aside from this, the welding direction is discarded in the direction opposite to the welding direction of the welding path 6 and moved to the welding end point 8a to complete the welding.

  Next, various examples of the welding path in the present embodiment will be described with reference to the weld bead diagrams shown in FIGS. The abandoned welding may be performed in a range of about 30 to 150 degrees with respect to the welding path 6 rather than in a substantially tangential direction of the welding path 6. That is, as the direction of the discard welding approaches the tangential direction of the welding path 6, the portion that overlaps with the joint portion to be originally welded increases, so it is necessary to increase the distance of the discard welding.

  In the example shown in FIG. 8, the welding start point 7 a is set on the end plate 2 in the direction of 30 degrees with respect to the tangential direction of the welding path 6, and the welding end point 8 a is in the direction of 30 degrees with respect to the tangential direction of the welding path 6. It is set on the tube seat 4. In FIG. 8, 10 is the width of the weld bead 6a.

  In the example shown in FIG. 9, the welding start point 7 a is set on the end plate 2 in the direction of 150 degrees with respect to the tangential direction of the welding path 6, and the welding end point 8 a is in the direction of 150 degrees with respect to the tangential direction of the welding path 6. It is set on the tube seat 4.

  In the example shown in FIG. 10, the welding start point 7 a is set on the end plate 2 in the direction of 30 degrees with respect to the tangential direction of the welding path 6, and the welding end point 8 a is in the direction of 30 degrees with respect to the tangential direction of the welding path 6. This is set on the end plate 2.

  In the example shown in FIG. 11, the welding start point 7 a is set on the end plate 2 in the direction of 150 degrees with respect to the tangential direction of the welding path 6, and the welding end point 8 a is in the direction of 150 degrees with respect to the tangential direction of the welding path 6. This is set on the end plate 2.

  In the example shown in FIG. 12, the welding start point 7 a is positioned in the same direction as the welding path 6 and is separated by a weld bead width 10 or more in the welding path 6, and the welding end point 8 a is also in the same direction as the welding path 6. The welding bead width is 10 or more. Thus, if it is a position away from the welding path 6 more than the width 10 of the weld bead, it is possible to set it as the position of the welding start point 7a or the welding end point 8a.

  Further, the shape of the weld bead can be adjusted to some extent by the welding current, the wire supply speed, etc., but by adopting the welding method shown in the present embodiment, even in the CMT welding where the melted part is shallow, the overlapping welded part 9 It is possible to ensure sufficient airtightness.

  Furthermore, in the above embodiment, the example in which the welding path 6 around the pipe seat is set to the left is described, but the welding start point and the welding end point described above may be reversed, and the welding path 6 may be clockwise. Even in that case, the same effect can be obtained.

  As described above, according to this embodiment, it is possible to obtain a container welding method capable of suppressing the occurrence of a nest (pinhole) that is likely to occur near the welding start point even when the container is CMT welded. it can. In addition, CMT welding makes it possible to manufacture pressure vessels (accumulators, receivers, etc.) with internal pressure that are used in refrigeration cycle devices and the like, and post-processing such as pickling for the purpose of removing spatter is not required. Therefore, manufacturing costs can be reduced by reducing the number of manufacturing steps. Furthermore, since the container can be manufactured by CMT welding, there is an effect that a container with a small distortion of the welded portion can be obtained.

A Container 1 Body 2 End plate (Pipe connection side)
3 End plate 4 Tube seat 5 Piping 6 Welding path (6a ... Weld bead)
7, 7a Weld start point 8, 8a Weld end point 9 Overlap weld 10 Width of weld bead.

Claims (6)

In the container welding method,
The container is manufactured by welding using CMT (Cold Metal Transfer) welding,
Abandon welding is performed by starting CMT welding from the position different from the joint to be welded toward the joint to be welded,
After arriving at the joint to be welded, CMT welding is performed for the joint to be welded continuously,
When the starting point of the main welding is reached, the vicinity of the starting point of the main welding is further continuously performed,
Thereafter, the welding is carried out by discarding to a position different from the joint portion to be continuously welded.   The container welding method according to claim 1, wherein the discard welding is performed in a range of 30 to 150 degrees with respect to a tangential direction of a welding path of a joint portion to be welded. In the welding method of the container, which has a body part and an end plate closing the end part of the body part, and a tube seat for connecting a pipe is attached to the end panel by welding,
The weld for attaching the tube seat to the end plate is manufactured by welding using CMT (Cold Metal Transfer) welding,
Abandon welding is performed by starting CMT welding from the position different from the joint to be welded toward the joint to be welded,
After reaching the joint to be welded, CMT welding is performed around the pipe seat, which is the joint to be welded continuously.
When the starting point of the main welding is reached, the vicinity of the starting point of the main welding is further continuously performed,
Thereafter, the welding is carried out by discarding to a position different from the joint portion to be continuously welded.   The welding start point for starting the CMT welding is set on the end plate, and the discard welding is performed in a range of 30 to 150 degrees with respect to the tangential direction of the welding path of the joint to be welded. The welding end point for terminating the CMT welding is either on the tube seat or on the end plate.   5. The welding start point according to claim 4, wherein the welding start point is on the end plate in the normal direction of the welding path, and the welding end point is on the pipe seat in the normal direction of the welding path. A welding method for a container.   A refrigeration cycle apparatus using the container produced by the method according to any one of claims 3 to 5 as an accumulator or a receiver constituting a refrigeration cycle.

Images