JP2024098801A - Welding method and can body manufacturing method - Google Patents

Abstract

To provide a welding method which makes plates less likely to be misaligned, and to provide a production method of a can body.SOLUTION: A welding method of the disclosure is used to join a first plate and a second plate to each other. The first plate has: a first surface part having a cylindrical shape; and a first end which is an end of the first surface part. The second plate has: a second surface part having a cylindrical shape; and a second end which is an end of the second surface part. The first end has a first bending part which is erected at an acute angle, directed to the radial outer side of the first surface part; and a second bending part which bends in an opposite direction of the first bending part at a tip side of the first end relative to the first bending part. The second end has a flare bending part erected at an obtuse angle, directed to the radial outer side of the second surface part. In a state that the first bending part and the second bending part and the flare bending part are placed in contact at the inner side of a bending portion between the first bending part and the second bending part, the second bending part is heated from the radial outer side to weld the first end and the second end to each other.SELECTED DRAWING: Figure 7

Description

This disclosure relates to a welding method and a method for manufacturing a can body.

Patent Document 1 discloses a welding method that can reduce misalignment between plate materials when welding them together. This welding method involves bringing the L-shaped ends of two plate materials into contact with each other, and then providing a gap between the L-shaped end of the second plate material and the eaves portion of the first plate material, so that the gap absorbs the misalignment between the plate materials.

JP 2012-148304 A

This disclosure provides a welding method that prevents plate materials from shifting during welding, and a method for manufacturing a can body.

The welding method disclosed herein is a welding method for joining a first plate material and a second plate material, in which the first plate material has a cylindrical first surface portion and a first end portion that is an end portion of the first surface portion, the second plate material has a cylindrical second surface portion and a second end portion that is an end portion of the second surface portion, the first end portion has a first bent portion that rises at an acute angle toward the radially outer side of the first surface portion, and a second bent portion that bends in the opposite direction to the first bent portion at a tip side of the first end portion relative to the first bent portion, and the second end portion has a flared bent portion that rises at an obtuse angle toward the radially outer side of the second surface portion, and the first bent portion and the second bent portion are in contact with each other inside the bend between the first bent portion and the second bent portion, and the second bent portion is heated from the radially outer side to weld the first end portion and the second end portion.

In the welding method and can body manufacturing method disclosed herein, the flare bend portion comes into contact with the second bend portion and the first bend portion. This makes it difficult for the plates to shift during welding.

FIG. 1 is a perspective view of a can body according to a first embodiment; 1 is a cross-sectional view of a can body according to a first embodiment of the present invention; Enlarged view of FIG. FIG. 3 is a cross-sectional view of the head plate and the body in a state where they are set in the welding device according to the first embodiment; Enlarged view of FIG. 1 is a cross-sectional view of a head plate and a fuselage after pressing in accordance with the first embodiment; Enlarged view of FIG.

(Knowledge and other information that forms the basis of this disclosure)
At the time when the inventors came to this disclosure, the technology of the welding method between plate materials was in a situation where both ensuring the quality of the welding and improving productivity were required. Therefore, in the industry, a technology was proposed to reduce the misalignment between the plate materials by deforming the end of the plate material as described in Patent Document 1, with the aim of improving the quality and productivity of the welding. Under such circumstances, the inventors discovered that when a gap as described in Patent Document 1 is provided, while the gap acts as a buffer to absorb the misalignment, there is a problem that it may cause the plate materials to be misaligned when aligned or welded. In particular, a thin-walled body and a head plate that are easily bent may be adopted for the hot water storage tank of a hot water supply device, which requires a thin-walled, lightweight tank from the standpoint of environmental consideration and cost. When such a body and a head plate are welded, the plate materials are more likely to be misaligned with each other in the conventional welding method as described in Patent Document 1. Therefore, in order to solve this problem, the inventors have come to constitute the subject of the present disclosure.
Therefore, the present disclosure provides a welding method that prevents plate materials from shifting from one another during welding.

Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted.
It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS.
[1-1. Configuration of can body]
Fig. 1 is a perspective view of a can body 1 manufactured using the welding method of the present disclosure. Fig. 2 is a cross-sectional view of the can body 1 cut along an axis AX. The axis AX in the figure is an axis passing through the center of the cylindrical shape formed by the first surface portion 11 and the second surface portion 21.
The can body 1 is a generally cylindrical container and is used as a hot water storage tank for a hot water supply system. The can body 1 has two generally hemispherical end plates (first plate material) 10 and a cylindrical body (second plate material) 20. The can body 1 is manufactured by joining the end plates 10 and the body 20, each of which is formed as an individual plate material, by arc welding.

The mirror plate 10 is a metal plate having a cylindrical first surface 11 and a dome-shaped dome portion 19. The thickness of the first surface 11 is plate thickness T1. In this embodiment, the metal constituting the mirror plate 10 is stainless steel. The mirror plate 10 is work-hardened by processing during manufacturing, and has greater rigidity than the body 20.

The body 20 is a metal plate having a cylindrical second surface 21. The second surface 21 is oriented along the first surface 11, and their respective axes AX are aligned. The thickness of the second surface 21 is plate thickness T2. The inner diameter D2 of the second surface 21 is equal to the inner diameter D1 of the first surface 11. In this embodiment, the metal constituting the body 20 is stainless steel.

In the can body 1, a bead 30 is formed between the first end 13, which is the end of the first surface 11, and the second end 23, which is the end of the second surface 21. The bead 30 is a part of the first end 13 and the second end 23 before welding that melts and then solidifies due to welding.

Figure 3 is an enlarged view of the bead 30 in the cross-sectional view of Figure 2. As shown in Figure 3, in the can body 1 of embodiment 1, the first surface 11 and the second surface 21 are arranged at aligned positions in the radial direction. The cross-sectional shape of the bead 30 connecting the head plate 10 and the body 20 is a flat shape with little radial bulge. When the bead 30 has such a flat shape, stress concentration in the bead 30 is reduced. The radially outward direction DO is the direction from the inside to the outside of the cylindrical shape formed by the first surface 11 and the second surface 21.

[1-2. Manufacturing method of can body]
Next, a method for manufacturing the above-mentioned can body 1 by welding the head plate 10 and the body 20 together will be described.
[1-2-1. Pre-welding process]
Fig. 4 is a cross-sectional view of the head plate 10 and the body 20 when set in the welding device W, showing a cross-section of the head plate 10 and the body 20 cut vertically along the axis AX. Fig. 5 is an enlarged view of Fig. 4, showing the first end 13 and the second end 23.

As shown in FIG. 4, the welding device W has a clamp W1 and two torches W2. The clamp W1 holds two end plates 10 in the direction of the axis AX, and holds the body 20 between the two end plates 10. At this time, the axis AX is horizontal. The clamp W1 can move in the direction of the axis AX of the first surface portion 11 and the second surface portion 21. The clamp W1 can also rotate around the axis AX of the first surface portion 11 and the second surface portion 21 in the circumferential direction of the first surface portion 11 and the second surface portion 21. The torch W2 is a device that generates heat by arc discharge and performs welding using the generated heat. The torch W2 is provided near the first end portion 13 and the second end portion 23, and performs arc discharge vertically from above to below. Also, as shown in FIG. 4, the welding device W may be configured to have a ring-shaped jig W3 that fixes the center of the body 20. The jig W3 is a tool that fastens and fixes substantially the entire circumference of the body 20 from the radially outward direction DO side, and can rotate around the axis AX in the circumferential direction of the first surface portion 11 and the second surface portion 21. The jig W3 prevents the body 20, which has a lower rigidity than the head plate 10, from bending and deforming. The jig W3 also makes it easier to position the body 20 relative to the head plate 10.

As shown in FIG. 5, the first end 13 of the head plate 10 before welding is formed with a first bent portion 15 that rises radially outward, and a second bent portion 17 that bends in the opposite direction to the first bent portion 15. The first bent portion 15 is formed by rising in a direction such that the bending angle between it and the first surface portion 11 is angle A1, and has a substantially linear shape in the cross section of FIG. 5. In addition, angle A1 is an acute angle. The first bent portion 15 is formed around the entire circumference of the first end 13.

The second bent portion 17 is formed closer to the tip 13a of the first end portion 13 than the first bent portion 15, and has a substantially linear shape in the cross-sectional view of FIG. 5. The second bent portion 17 is bent in a direction such that the bending angle between the second bent portion 17 and the first bent portion 15 is angle A2. In this embodiment, angle A2 is an acute angle and is equal to angle A1. Therefore, the second bent portion 17 extends along the first surface portion 11 and has a cylindrical shape parallel to the axis AX. In addition, the second bent portion 17 is perpendicular to the radially outward direction DO.

A curved first corner 14 is formed between the portion of the first end 13 along the first surface 11 and the first bent portion 15. The first corner 14 is a fold formed by the process of forming the first bent portion 15, and is a rounded corner.

A curved second corner 16 is formed between the first bent portion 15 and the second bent portion 17. The second corner 16 is a fold formed by the process of forming the second bent portion 17, and is a rounded corner.

Before welding, the second end 23 has a flat shape and extends in the direction of the axis AX and parallel to the second surface 21. Therefore, the thickness of the second end 23 is the plate thickness T2, similar to the second surface 21. In addition, a flat end face 23a that is approximately perpendicular to the second end 23 is formed at the tip of the second end 23. The end face 23a faces the first corner 14 of the first end 13.

After the head plate 10 and the body 20 are set on the welding device W as shown in Figures 4 and 5, the welding device W applies pressure by moving the clamp W1 in a direction in which the two head plates 10 press against each other in the direction of the axis AX. As a result, the head plate 10 and the body 20 are strongly pressed against each other along the direction of the axis AX.

Figure 6 is a cross-sectional view of the head plate 10 and body 20 set in the welding device W after pressure is applied, showing a cross-section of the head plate 10 and body 20 cut vertically along the axis AX. Figure 7 is an enlarged view of Figure 6, showing the first end 13 and the second end 23. Figure 6 shows the pressure direction of the clamp W1.

As shown in Figures 6 and 7, in this embodiment, the clamp W1 moves and the head plate 10 and the body 20 are pressed firmly against each other along the axis AX, forming a flare bend 25 at the second end 23.

The flare bend 25 is formed by pressing the first corner 14 and the first bent portion 15 firmly against the end surface 23a of the second end 23 by applying pressure, and is raised from the second surface 21 in the radially outward direction DO. The flare bend 25 is raised in a direction such that the angle between the flare bend 25 and the second surface 21 is angle A3. Angle A3 is an obtuse angle. In this embodiment, the sum of angle A1 and angle A3 is 180° or more.

When the flare bend 25 is formed, the end face 23a moves radially outward while sliding on the outer surface 14a, which is the outer surface of the curve of the first corner 14, and the inner surface 15a, which is the inner surface of the bend between the first bend 15 and the second bend 17 of the first bend 15. The radial outward movement of the end face 23a stops when it comes into contact with the inner surface 17a, which is the inner surface of the bend between the first bend 15 and the second bend 17 of the second bend 17. For this reason, in this embodiment, the end face 23a of the second end 23, which is the tip of the flare bend 25, makes line contact in the circumferential direction with the inner surfaces 15a, 17a of the first bend 15 and the second bend 17.

In this embodiment, the radius of curvature of the inner surface 16a, which is the inner surface of the curve of the second corner portion 16, is smaller than the plate thickness T2 of the second surface portion 21 and the second end portion 23. Therefore, the end surface 23a, which is the tip of the flare bend portion 25, is likely to come into line contact in the circumferential direction with the inner surfaces 15a, 17a of the first bend portion 15 and the second bend portion 17, respectively.

In addition, in this embodiment, the second end 23 where the flare bend 25 is formed is formed on the body 20, which has a lower rigidity than the head plate 10. This makes it easier to form the flare bend 25 on the second end 23.

When the flare bend portion 25 is formed, the pre-welding process is completed and the welding process begins.

[1-2-2. Welding process]
In the welding process, the welding device W performs arc welding with the torch W2 while the clamp W1 rotates the head plate 10 and the body 20 around the axis AX. At this time, the clamp W1 applies a force along the axis AX to the head plate 10 in the direction in which the head plate 10 and the body 20 press against each other. This makes it easier for the end face 23a to make line contact with both the inner surfaces 15a, 17a of the first bent portion 15 and the second bent portion 17. In addition, the end face 23a is sandwiched from the radial inside and the radial outside by the two inner surfaces 15a, 17a. Therefore, the end face 23a is restricted from moving in the radial direction, and the first end 13 and the second end 23 are less likely to shift from each other in the direction along the axis AX and in the radial direction.

In this way, the end face 23a is restricted in the radial direction and the direction along the axis AX relative to the inner surfaces 15a, 17a over its entire circumference. Therefore, in addition to the misalignment caused by the arrangement of the mirror plate 10 and the body 20, the misalignment caused by the deflection of the first end 13 and the second end 23 can also be suppressed.

The welding device W has a touch sensor (not shown) that detects the position of the tip 13a of the first end 13 located vertically above. Using the information on the position of the tip 13a detected by the touch sensor, the welding device W moves the torch W2 in the direction of the axis AX and in the radial direction, and causes the torch W2 to arc discharge, aiming at the inside of the target range R in FIG. 7. In this embodiment, the target range R is the outer surface 17b, which is the outer surface of the bend between the first bend 15 and the second bend 17, of the second bend 17, and the second corner 16. The outer surface 17b and the second corner 16 are heated from the radial outside by the torch W2.

The first bent portion 15 and the second bent portion 17 are melted by the heat from the torch W2. The flare bent portion 25 is melted by the heat conducted from the first bent portion 15 and the second bent portion 17. In this manner, in this embodiment, welding is performed by melting the flare bent portion 25, the first bent portion 15, and the second bent portion 17, so that the amount of metal melted can be increased and welding can be performed with stable quality. In addition, the melted flare bent portion 25, the first bent portion 15, and the second bent portion 17 act as a filler material that fills the gap between the first end portion 13 and the second end portion 23, so that the first end portion 13 and the second end portion 23 can be welded without using a filler material.

Here, in this embodiment, the length L of the second bent portion 17 along the axis AX is more than twice the plate thickness T2, which is the thickness of the second surface portion 21 and the second end portion 23. Therefore, the target range R can be made wider, and the area of the outer surface 17b of the second bent portion 17 becomes larger, making it easier to heat and easier to weld. In addition, since the second bent portion 17 is long, the end surface 23a of the second end portion 23 is less likely to come off the inner surface 17a of the second bent portion 17. Therefore, during welding, the head plate 10 and the body 20 are less likely to shift radially. Furthermore, since the second bent portion 17 is long, the amount of metal melted during welding can be increased, making it easier to stabilize the quality of the welding without using a filler metal.

In addition, in this embodiment, since the end face 23a is likely to be in line contact with both the inner surfaces 15a, 17a of the first bent portion 15 and the second bent portion 17, heat is likely to be transferred from the first end portion 13 to the second end portion 23 via the end face 23a. This makes it easier to melt the flare bent portion 25 and stabilize the quality of the welding. In particular, in this embodiment, the end face 23a is in contact with the inner surface 17a, which is the surface opposite the outer surface 17b of the second bent portion 17 heated by the torch W2. As a result, the heat applied to the outer surface 17b from the torch W2 is quickly transferred to the second end portion 23 via the inner surface 17a and the end face 23a, making it easier to melt the flare bent portion 25.

In addition, in this embodiment, since the second bent portion 17 has a generally cylindrical shape extending along the first surface portion 11, the torch W2 located radially outside the second bent portion 17 can easily heat the outer surface 17b. Also, since the second bent portion 17 is along the first surface portion 11 and is generally perpendicular to the radially outward direction DO, when the end face 23a tries to shift radially outward, the inner surface 17a of the second bent portion 17 can easily restrict the movement of the end face 23a.

The torch W2 performs an arc discharge on the outer surface 17b and the second corner 16 of the entire circumference of the target range R, and as shown in FIG. 3, the first end 13 and the second end 23 are joined around the entire circumference via the bead 30. This completes the welding process and the manufacture of the can body 1.

[1-3. Effects, etc.]
As described above, in this embodiment, the welding method is a welding method for joining a head plate 10 and a body 20, in which the head plate 10 has a cylindrical first surface portion 11 and a first end portion 13 which is an end portion of the first surface portion 11, the body 20 has a cylindrical second surface portion 21 and a second end portion 23 which is an end portion of the second surface portion 21, and the first end portion 13 has a first bent portion 15 which rises at an acute angle radially outward from the first surface portion 11, and a second end portion 23 which is closer to the tip 13a of the first end portion 13 than the first bent portion 15. and a second bent portion 17 that bends in the opposite direction to the first bent portion 15, and the second end 23 has a flare bent portion 25 that rises at an obtuse angle radially outward from the second surface portion 21, and on the inside of the bend between the first bent portion 15 and the second bent portion 17, the first bent portion 15 and the second bent portion 17 are in contact with an end face 23a located at the tip of the flare bent portion 25, and the second bent portion 17 is heated from the radially outside to weld the first end 13 and the second end 23 together.
According to this configuration, the end face 23a comes into contact with the first bent portion 15 and the second bent portion 17, thereby restricting the radial movement of the flare bent portion 25. Therefore, the head plate 10 and the body 20 are less likely to shift during welding. Furthermore, during welding, the second bent portion 17 is heated from the radially outer side with the end face 23a in contact with the first bent portion 15 and the second bent portion 17. Therefore, the heat applied to the second bent portion 17 is easily transferred to the flare bent portion 25 via the end face 23a, making it easier to stabilize the quality of the welding.

Furthermore, as in this embodiment, the welding method may be configured to weld the first end 13 and the second end 23 while pressing the head plate 10 and the body 20 against each other along the axis AX of the first surface portion 11.
According to this configuration, the end face 23a is more likely to come into contact with the first bent portion 15 and the second bent portion 17, and radial movement is more likely to be restricted. Therefore, the head plate 10 and the body 20 are less likely to shift during welding. In addition, since the end face 23a is more likely to come into contact with the first bent portion 15 and the second bent portion 17, heat is more likely to be transferred from the second bent portion 17 to the flare bent portion 25 via the end face 23a, and the quality of the welding is more likely to be stable.

Furthermore, as in this embodiment, in the welding method, the flare bend portion 25 may be formed by pressing the head plate 10 and the body 20 against each other along the axis AX of the first surface portion 11 with the second end portion 23 in contact with the first bend portion 15.
According to this configuration, the process of forming the flare bent portion 25 and the welding can be carried out continuously, improving the productivity of the welding.

Furthermore, as in this embodiment, the radius of curvature of the inner surface 16a of the second corner portion 16 between the second bent portion 17 and the first bent portion 15 may be configured to be less than or equal to the plate thickness T2, which is the thickness of the second end portion.
According to this configuration, the end surface 23 a of the flare bent portion 25 is more likely to come into line contact with the first bent portion 15 and the second bent portion 17 .

Furthermore, as in this embodiment, the bending angle A2 between the first bending portion 15 and the second bending portion 17 may be configured to be equal to the bending angle A1 between the first surface portion 11 and the first bending portion 15.
According to this configuration, the second bent portion 17 extends in a direction substantially perpendicular to the radial direction, which makes it easier to restrict the movement of the end face 23a toward the radial outside. This makes it easier to prevent the head plate 10 and the body 20 from being misaligned during welding. In addition, since the second bent portion 17 is heated from the radial outside, the second bent portion 17 can be easily heated by extending in a direction substantially perpendicular to the radial direction.

Furthermore, as in this embodiment, the length L, which is the dimension of the second bent portion 17 in the direction along the axis AX of the first surface portion 11, may be configured to be more than twice the plate thickness T2, which is the thickness of the second end portion 23.
According to this configuration, the length L of the second bent portion 17 is more than twice the plate thickness T2 of the second end portion 23, so that the inner surface 17a of the second bent portion 17 can easily press the end surface 23a from the radial outside. Therefore, the head plate 10 and the body 20 are less likely to shift during welding. In addition, since the second bent portion 17 is heated from the radial outside, the second bent portion 17 can be easily heated by setting the dimension along the axis AX intersecting the radial direction to be large. Furthermore, since the dimension of the second bent portion 17 is large, the amount of metal melted during welding increases, making it easier to stabilize the quality of the welding without using a filler metal.

Other Embodiments
As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create a new embodiment.
Therefore, other embodiments will be exemplified below.

In the manufacturing method of the can body of the first embodiment, it has been explained that the plate material having the first end 13 on which the first bent portion 15 and the second bent portion 17 are formed is the head plate 10, and the plate material having the flared bent portion 25 and the flat end surface 23a is the body 20, but this is only one example. For example, the first bent portion and the second bent portion may be formed in the body 20, and the flared bent portion and the flat end surface may be formed in the head plate 10.

That is, the method for manufacturing a can body is a method for manufacturing a can body in which a head plate 10 and a cylindrical body 20 are welded to produce a can body 1, in which one of a first plate material having a first bent portion 15 and a second bent portion 17 formed therein, and a second plate material having a flare bent portion 25 formed therein, is used as the head plate 10, and the other of the first plate material and the second plate material, which is different from the one of the first plate material and the second plate material, is used as the body 20, and the head plate and the body are welded together using the welding method described in the above embodiment.
According to this configuration, when manufacturing the can body 1, misalignment between the first end 13 and the second end 23 can be suppressed when welding the end plate 10 and the body 20, and the quality of the welding can be more easily stabilized.

In the first embodiment, the inner diameter D1 of the first surface portion 11 and the inner diameter D2 of the second surface portion 21 are described as being equal, but this is only one example. For example, the inner diameter D2 may be larger than the inner diameter D1, and the end face 23a may be located radially outward from the first surface portion 11 before the flare bend portion 25 is formed. In this case, the end face 23a does not contact the outer surface 14a of the first corner portion 14 but contacts the inner surface 15a of the first bent portion 15, so that the end face 23a is easily guided radially outward along the inner surface 15a. This makes it easier to form the flare bent portion 25. The flare bent portion 25 can also be easily formed by expanding the second end portion 23 before the flare bent portion 25 is formed.

In the first embodiment, the head plate 10 and the body 20 are described as being stainless steel, but this is just one example. The head plate 10 and the body 20 may each be made of a metal other than stainless steel. Also, the head plate 10 and the body 20 may each be made of a different type of metal.

In the first embodiment, the welding device W is described as detecting the position of the tip 13a of the first end 13 by a touch sensor, but this is just one example. For example, the welding device W may detect the position of the tip 13a by a non-contact sensor, such as a visual sensor or an optical sensor such as a laser displacement sensor, instead of a touch sensor.

In addition, in the welding method described in embodiment 1, welding may be performed while inserting a filler material such as a filler rod or filler wire into the arc atmosphere.

The above-described embodiments are intended to illustrate the technology disclosed herein, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[Configuration supported by the above embodiment]
The above embodiment supports the following configurations.

(Additional Note)
(Technology 1) A welding method for joining a first plate and a second plate, wherein the first plate has a cylindrical first surface portion and a first end portion that is an end of the first surface portion, the second plate has a cylindrical second surface portion and a second end portion that is an end of the second surface portion, the first end portion has a first bent portion that rises at an acute angle toward the radially outward side of the first surface portion, and a second bent portion that bends in an opposite direction to the first bent portion at a tip side of the first end portion relative to the first bent portion, and the second end portion has a flared bent portion that rises at an obtuse angle toward the radially outward side of the second surface portion, and the first bent portion and the second bent portion and the flared bent portion are in contact with each other inside the bend between the first bent portion and the second bent portion, and the second bent portion is heated from the radially outward side to weld the first end and the second end.
As a result, the flare bent portion comes into contact with the first bent portion and the second bent portion, and radial movement is restricted. Therefore, the first plate material and the second plate material are less likely to shift during welding. Furthermore, during welding, the second bent portion is heated from the radial outside while the flare bent portion is in contact with the first bent portion and the second bent portion, so that the heat applied to the second bent portion is easily transferred to the flare bent portion. Therefore, the quality of the welding is more likely to be stable.

(Technology 2) A welding method according to Technology 1, in which the first end portion and the second end portion are welded together while the first plate material and the second plate material are pressed against each other along the axis of the first surface portion.
This makes it easier for the flare bent portion to come into contact with the first bent portion and the second bent portion, and makes it easier to restrict radial movement. This makes it harder for the first plate material and the second plate material to shift during welding. In addition, since the flare bent portion comes into contact with the first bent portion and the second bent portion, heat is easily transferred from the second bent portion to the flare bent portion, and the quality of the welding is easily stabilized.

(Technology 3) A welding method according to Technology 1 or 2, in which the flare bend portion is formed by pressing the first plate material and the second plate material against each other along the axis of the first surface portion with the second end portion in contact with the first bent portion.
This allows the step of forming the flare bent portion and the welding to be carried out consecutively, improving welding productivity.

(Technology 4) A welding method according to any one of Technologies 1 to 3, wherein a radius of curvature between the second bent portion and the first bent portion is equal to or less than a thickness of the second end portion.
This makes it easier for the flare bent portion to come into line contact with the first bent portion and the second bent portion.

(Technology 5) A welding method described in any one of Technologies 1 to 4, wherein a bending angle between the first bent portion and the second bent portion is equal to a bending angle between the first surface portion and the first bent portion.
Since the second bent portion extends in a direction substantially perpendicular to the radial direction, it is easy to restrict the movement of the flare bent portion toward the radial outward direction. Therefore, it is easy to suppress the first plate material and the second plate material from being misaligned during welding. In addition, since the second bent portion is heated from the radial outward direction, the second bent portion 17 is easily heated by extending in a direction substantially perpendicular to the radial direction.

(Technology 6) A welding method according to any one of Technologies 1 to 5, wherein a dimension of the second bent portion in a direction along the axis of the first surface portion is at least twice the thickness of the second end portion.
As a result, the dimension of the second bent portion 17 along the axis is at least twice the thickness of the second end portion, so that the second bent portion can easily press the flare bent portion from the radially outer side. Therefore, the first plate material and the second plate material are less likely to shift during welding. In addition, since the second bent portion is heated from the radially outer side, the second bent portion can be easily heated by setting the dimension along the axis intersecting the radial direction to be large. Furthermore, since the dimension of the second bent portion is large, the amount of metal melted during welding increases, making it easier to stabilize the quality of the welding.

(Technology 7) A method for manufacturing a can body, in which a head plate and a cylindrical body are welded to produce a can body, wherein one of the first plate material and the second plate material is used as the head plate, and the other of the first plate material and the second plate material, which is different from the one of the first plate material and the second plate material, is used as the body, and the head plate and the body are welded using a welding method described in any one of Technologies 1 to 6.
This makes it possible to suppress misalignment between the head plate and the body when welding them together during the manufacture of the can body, and also makes it easier to stabilize the quality of the welding.

This disclosure is applicable to a method for welding plate materials together. In particular, this disclosure is preferably applicable to a welding method for manufacturing a container having a body and a head plate, such as a hot water storage tank.

REFERENCE SIGNS LIST 1 can body 10 head plate 11 first surface 13 first end 13a tip 14 first corner 14a outer surface 15 first bent portion 15a inner surface 16 second corner 16a inner surface 17 second bent portion 17a inner surface 17b outer surface 19 dome portion 20 body 21 second surface 23 second end 23a end surface 25 flare bent portion 30 bead W welding device W1 clamp W2 torch W3 jig

Claims (7)

A welding method for joining a first plate material and a second plate material, comprising:
The first plate member has a cylindrical first surface portion and a first end portion which is an end portion of the first surface portion,
The second plate member has a cylindrical second surface portion and a second end portion which is an end portion of the second surface portion,
the first end portion has a first bent portion that rises at an acute angle toward the radially outer side of the first surface portion, and a second bent portion that is bent in an opposite direction to the first bent portion on a tip side of the first end portion relative to the first bent portion,
The second end portion has a flare bent portion that rises at an obtuse angle toward a radially outer side of the second surface portion,
In a state where the first bent portion and the second bent portion are in contact with the flare bent portion on the inside of the bend between the first bent portion and the second bent portion, the second bent portion is heated from the radially outer side to weld the first end portion and the second end portion.
Welding method. The first end portion and the second end portion are welded together while pressing the first plate material and the second plate material against each other along the axis of the first surface portion.
The welding method according to claim 1. The flare bent portion is formed by pressing the first plate material and the second plate material against each other along an axis of the first surface portion with the second end portion in contact with the first bent portion.
The welding method according to claim 1. A radius of curvature between the second bent portion and the first bent portion is equal to or less than a thickness of the second end portion.
The welding method according to claim 1. A bending angle between the first bending portion and the second bending portion is equal to a bending angle between the first surface portion and the first bending portion.
The welding method according to claim 1. A dimension of the second bent portion in a direction along the axis of the first surface portion is at least twice the thickness of the second end portion.
The welding method according to claim 1. A method for manufacturing a can body, comprising the steps of: manufacturing a can body by welding a head plate and a cylindrical body, the method comprising the steps of:
one of the first plate material and the second plate material is used as the end plate;
As the fuselage, a plate material different from the one of the first plate material and the second plate material is used,
The head plate and the fuselage are welded together using the welding method according to any one of claims 1 to 6.
Manufacturing method of can body.

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