JP7573202B2 - Welding method and can body manufacturing method - Google Patents

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 suppress gaps and misalignment in the thickness direction between plate materials when welding the two plates together. In this welding method, a eaves portion having a first bent portion and a second bent portion is formed on a first plate material, and welding is performed with the second plate material pressed against the eaves portion.

JP 2017-113796 A

This disclosure provides a welding method that makes it easy to align plate materials when 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, and 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, and the first end portion is formed with a first bent portion that expands radially outward from the first surface portion, a second bent portion that is bent in the opposite direction to the first bent portion on the tip side of the first end portion from the first bent portion, and a third bent portion that is bent in the opposite direction to the second bent portion on the tip side from the second bent portion, and the second end portion is flat in shape, and the joint between the first bent portion and the second bent portion and the end face of the second end portion are pressed against each other, and the first end portion and the second end portion are welded by heating from the third bent portion.

The welding method and can body manufacturing method disclosed herein can guide the second end 23 by the first bent portion, the second bent portion, and the third bent portion formed on the first end when aligning the first end and the second end. This makes it easier to align the first plate material and the second plate material.

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. 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. FIG. 3 is a cross-sectional view of the head plate and the fuselage in an aligned state according to the first embodiment; Enlarged view of FIG.

(The knowledge and other information that formed 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 state where both ensuring the quality of the welding and improving productivity were required. Therefore, in the industry, a technology for suppressing the misalignment of the plate materials by deforming the ends of the plate materials as described in Patent Document 1 was proposed with the aim of improving the quality and productivity of the welding. Under such circumstances, the inventors discovered that when the eaves portion has a shape as described in Patent Document 1, there is a problem that when the two plate materials are aligned, the end faces of the plate materials collide with each other, and the plate materials are likely to be misaligned. In particular, in the hot water storage tank used in the hot water supply device, a thin and lightweight tank is required from the viewpoint of environmental consideration and cost, and a plate material with low rigidity and easy to bend is sometimes adopted. In such a case, it becomes even more difficult to align the plate materials with each other with the welding method as described in Patent Document 1. 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 makes it easy to align plate materials with each other.

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 in the radial direction. An 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. Due to its shape, the mirror plate 10 has greater rigidity than the body plate 10.

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 the respective axes AX are coincident. The thickness of the second surface 21 is plate thickness T2. The inner diameter D2 of the second surface 21 is larger than the inner diameter D1 of the first surface 11. In this embodiment, specifically, the inner diameter D2 is larger than the inner diameter D1 by more than twice the plate thickness T2 of the second surface 21. 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 portion of the first end 13 and the second end 23 that were melted by welding before welding and then solidified.

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 positioned at positions shifted radially by a misalignment d with respect to their respective inner diameter surfaces. The misalignment d is greater than the plate thickness T2 of the second surface 21 and corresponds to half the difference between the inner diameter D2 and the inner diameter D1. Since the misalignment d is greater than the plate thickness T2 of the second surface 21, the second surface 21 is positioned radially outward from the outer diameter surface of the first surface 11. 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.

The cross-sectional shape of the bead 30 connecting the head plate 10 and the body 20 is inclined radially outward in the DO direction from the first end 13 to the second end 23, and 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.

[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]
[1-2-1-1. Setting for welding equipment]
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. 4 shows the state immediately after the head plate 10 and the body 20 are set in the welding device W, and the head plate 10 and the body 20 are spaced apart.

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 with their first ends 13 facing each other. At this time, the axis AX is horizontal. The body 20 is held between the two end plates 10 so that the second ends 23 located at both ends in the direction along the axis AX face the first ends 13 of the end plates 10. 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 rotate in the circumferential direction of the first surface portion 11 and the second surface portion 21 around the axis AX 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 13 and the second end 23, and performs arc discharge vertically from above to below. As shown in FIG. 4, the welding device W may also be configured to have a ring-shaped jig W3 that fixes the center of the body 20. The jig W3 is a tool that tightens and fixes substantially the entire circumference of the body 20 from the radially outward direction DO side, and is rotatable in the circumferential direction of the first surface portion 11 and the second surface portion 21 around the axis AX. 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.

Figure 5 is an enlarged view of Figure 4, showing the first end 13. Note that Figure 5 also shows a first direction DA that is parallel to the axis AX and points from the dome portion 19 to the first end 13, and a second direction DB that is parallel to the axis AX and points from the first end 13 to the dome portion 19. That is, the first direction DA is the direction toward the fuselage 20 when viewed from the mirror plate 10, and the second direction DB is the direction toward the mirror plate 10 when viewed from the fuselage 20.

As shown in FIG. 5, the first end 13 of the head plate 10 before welding is formed with an eaves portion 15 that is bent in three stages and expands from the first direction DA toward the radially outward direction DO. By forming the eaves portion 15, the tip 15a of the first end 13 is located radially outward from the first surface portion 11. The eaves portion 15 has a first bent portion 17a that expands radially outward from the first surface portion 11, a second bent portion 17b that bends in the opposite direction to the first bent portion 17a, and a third bent portion 17c that bends in the opposite direction to the second bent portion 17b.

The first bent portion 17a is a connection portion with the flat cylindrical second surface portion 21 in the eaves portion 15, and is curved at an angle A1 from the first surface portion 11 in the cross section of Figures 4 and 5. Here, the angle A1 is an obtuse angle. Since the first bent portion 17a is curved in a direction expanding radially outward from the first surface portion 11, the outer surface 17a1 on the outside of the curve of the first bent portion 17a is part of the inner diameter side surface 15b2 of the eaves portion 15. In addition, the inner surface 17a2 on the inside of the curve of the first bent portion 17a is part of the outer diameter side surface 15b1 of the eaves portion 15. In addition, the outer diameter side surface 15b1 is a curved surface that is curvedly connected to the outer diameter side surface of the first surface portion 11 in the eaves portion 15. In addition, the inner diameter side surface 15b2 is a curved surface that is curvedly connected to the inner diameter side surface of the first surface portion 11 in the eaves portion 15.

The second bent portion 17b is located on the tip 15a side, i.e., on the first direction DA side, of the first bent portion 17a in the eaves portion 15, and is curved at an angle A2 in the cross section of Figures 4 and 5. Here, the angle A2 is an obtuse angle. The second bent portion 17b is curved in the opposite direction to the first bent portion 17a, i.e., in the direction falling along the first surface portion 11 from the radially outer side. Therefore, the outer surface 17b1 of the second bent portion 17b is part of the outer diameter side surface 15b1 of the eaves portion 15. Also, the inner surface 17b2 of the second bent portion 17b is part of the inner diameter side surface 15b2 of the eaves portion 15.

The third bent portion 17c is located closer to the tip 15a than the second bent portion 17b in the eaves portion 15, and is curved at an angle A3 in the cross section of Figures 4 and 5. Here, angle A3 is an obtuse angle. The third bent portion 17c is curved in the opposite direction to the second bent portion 17b, that is, in a direction rising radially outward from the first surface portion 11. Therefore, the outer surface 17c1 of the third bent portion 17c is part of the inner diameter side surface 15b2 of the eaves portion 15. In addition, the inner surface 17c2 of the third bent portion 17c is part of the outer diameter side surface 15b1 of the eaves portion 15.

The inner diameter side surface 15b2 has a first connection surface (seam) 16a, a second connection surface 16b, and a third connection surface 16c. The first connection surface 16a is a surface from the portion of the outer surface 17a1 of the first bent portion 17a on the first direction DA side to the portion of the inner surface 17b2 of the second bent portion 17b on the second direction DB side. The second connection surface 16b is a surface from the portion of the outer surface 17c1 of the third bent portion 17c on the second direction DB side to the portion of the inner surface 17b2 of the second bent portion 17b on the first direction DA side. The third connection surface 16c is a surface from the portion of the outer surface 17c1 of the third bent portion 17c on the first direction DA side to the tip 15a.

Each of these connection surfaces 16a, 16b, and 16c is open so that the first direction DA side is located radially outward with respect to the first surface portion 11. The opening angle of the first connection surface 16a, which opens in the first direction DA side with respect to the first surface portion 11 as a reference (for example, angle B1 in FIG. 5), is an acute angle. Also, the opening angle of the second connection surface 16b with respect to the first surface portion 11 as a reference (for example, angle B2 in FIG. 5) is an acute angle and is smaller than the opening angle of the first connection surface 16a. Furthermore, the opening angle of the third connection surface with respect to the first surface portion 11 as a reference (for example, angle B3 in FIG. 5) is an acute angle and is larger than the opening angle of the second connection surface 16b. That is, the opening angles of the first connection surface 16a and the third connection surface 16c are larger than the opening angle of the second connection surface 16b, and the opening angles of the connection surfaces 16a, 16b, and 16c are acute angles. In this embodiment, bending portions 17a, 17b, and 17c are formed so that they alternately bend in opposite directions, creating the above-mentioned relationship between the opening angles of connection surfaces 16a, 16b, and 16c.

[1-2-1-2. Alignment of headboard and fuselage]
Figure 6 is a cross-sectional view of the head plate 10 and the fuselage 20 in proper alignment with one another, taken along the axis AX and cut vertically through the head plate 10 and the fuselage 20. Figure 7 is an enlarged view of Figure 6, showing the first end 13 and the second end 23.

As shown in FIG. 6, after the head plate 10 and the body 20 are set, the welding device W moves a pair of clamps W1 to align the first end 13 of the head plate 10 and the second end 23 of the body 20 so that they come into contact with each other. At this time, the welding device W uses the clamps W1 and the jig W3 to align the first surface 11 and the second surface 21 so that they are coaxial.

As shown in FIG. 7, the second end 23 has a flat shape and has an end face 23a that is approximately perpendicular to the second end 23. When the first end 13 and the second end 23 are properly aligned, the first surface 11 and the second surface 21 are approximately coaxial, so the second surface 21 is located radially outward from the first surface 11 by the misalignment d. Also, since the second end 23 is flat, the thickness of the second end 23 is the plate thickness T2, and when properly aligned, the second end 23 is in a position shifted radially outward from the first surface 11 by the misalignment d. Therefore, the inner diameter side surface of the second end 23 is located radially outward from the first surface 11 by the misalignment d, and the end face 23a contacts the inner diameter side surface 15b2 of the eaves portion 15. More specifically, the end face 23a contacts the first connection surface 16a of the inner diameter side surface 15b2. The welding device W completes the alignment when the entire circumference of the end face 23a comes into line contact with the first connection surface 16a as shown in FIG. 7.

Up to this point, alignment has been explained without taking into account the deflection or axial misalignment of the head plate 10 and the body 20. However, in reality, the body 20 in particular is prone to deflection, and axial misalignment can occur even during axial alignment using the clamp W1 and the jig W3. As a result, when the clamp W1 moves the head plate 10, part of the second end 23 of the body 20 may shift radially inward from the correct position.

As described above, in this embodiment, when properly aligned, the second end 23 is shifted radially outward by the misalignment d with respect to the first surface 11. Therefore, even if the second end 23 is shifted radially inward from the state when properly aligned, the end face 23a is likely to come into contact with the inner diameter side surface 15b2 of the eaves portion 15. This makes it easier to prevent the second end 23 from slipping radially inward beyond the first surface 11. In particular, when the misalignment d is larger than the plate thickness T2 of the second surface 21, as in this embodiment, it is easier to effectively prevent the second end 23 from slipping radially inward beyond the first surface 11.

In addition, when the clamp W1 moves the mirror plate 10, due to deflection of the mirror plate 10 or the body 20, or axial misalignment, a portion of the second end 23 may shift radially outward from the correct position.

For example, it is conceivable that the second end 23 is shifted radially outward, causing a part of the end face 23a to come into contact with the second connection face 16b, which is radially outward from the first connection face 16a. As described above, the opening angle of the second connection face 16b is an acute angle, which is smaller than the opening angle of the first connection face 16a. For this reason, the end face 23a and the second connection face 16b are unlikely to face each other, and the end face 23a is likely to be guided by the second connection face 16b and move radially inward. The second end 23 that has moved radially inward from the second connection face 16b comes into contact with the first connection face 16a. At this time, the end face 23a is likely to come into contact with the first connection face 16a, which has a larger opening angle than the second connection face 16b, and to come to rest. Thus, in this embodiment, even if a portion of end face 23a contacts second connection face 16b, end face 23a can be easily guided to first connection face 16a, and second end 23 can be easily aligned in the appropriate position.

The second connection surface 16b has a small opening angle and is therefore easy to guide the end surface 23a, but on the other hand, its projected area as viewed along the axis AX is small and its width in the radial direction is narrow. For this reason, when the clamp W1 moves the mirror plate 10, a part of the second end 23 may be located radially outward of the second connection surface 16b. In such a case, in the conventional configuration as described in Patent Document 1, a two-stage curved eaves portion is used, so that the end surface 23a and the tip of the eaves portion come into contact, and a gap or misalignment in the plate thickness direction is likely to occur between the second end 23 and the eaves portion.

In contrast, in this embodiment, the eaves portion 15 has three bent portions 17a, 17b, and 17c that alternately bend in opposite directions, and has a three-stage curved shape. Therefore, a third connection surface 16c is formed radially outward of the second connection surface 16b, with an opening angle larger than that of the second connection surface 16b. Because the opening angle of the third connection surface 16c is larger, the projected area as viewed along the axis AX and the width in the radial direction are larger than those of the second connection surface 16b. Therefore, when the clamp W1 moves the mirror plate 10, even if a part of the second end 23 is located radially outward of the second connection surface 16b, the third connection surface 16c is likely to come into contact with the end surface 23a.

In addition, since the opening angle of the third connection surface 16c is an acute angle, it is easy to guide the contacted end surface 23a toward the inner diameter side. Furthermore, the second connection surface 16b and the first connection surface 16a are located on the inner diameter side of the third connection surface 16c in that order from the side closest to the third connection surface 16c, and the opening angle of the second connection surface 16b is smaller than the opening angle of the first connection surface 16a. Therefore, the end surface 23a guided toward the inner diameter side from the third connection surface 16c is further guided toward the inner diameter side by the second connection surface 16b, and is likely to come into contact with the first connection surface 16a and come to rest. Thus, in this embodiment, even if a part of the second end 23 is located further outboard than the second connection surface 16b, it is easy to guide the end surface 23a to the first connection surface 16a.

In this manner, in this embodiment, when aligning the first end 13 and the second end 23 using the clamp W, even if the second end 23 shifts radially outward from the correct position, it is easy to guide the second end 23 to the correct position.

In this way, in order to form connection surfaces 16a, 16b, 16c that can easily guide second end 23 to the correct position when second end 23 deviates radially outward from the correct position, it is desirable that angles A1, A2, A3 are each obtuse angles, as in this embodiment. This results in first connection surface 16a having a shape that opens radially outward on the first direction DA side, i.e., the body 20 side. Also, it is easier to form eaves portion 15 than when eaves portion 15 is formed by bending bent portions 17a, 17b, 17c at an acute angle.

Moreover, it is more desirable that angle A2 be an obtuse angle greater than angle A1, as in this embodiment. This makes it easier to form the second connection surface 16b in a shape that opens radially outward on the first direction DA side, i.e., the body 20 side, regardless of the obtuse angle that angle A1 is set to.

Furthermore, it is even more desirable that angle A3, as in this embodiment, satisfies the following relational expression (1).

A3<90°+A2-A1...(1)

As a result, as long as angle A1 is an obtuse angle and angle A2 is an obtuse angle greater than angle A1, it is easy to make the third connection surface 16c have a shape that opens radially outward on the first direction DA side, i.e., on the body 20 side, for any combination of angles A1 and A2.

In addition, in this embodiment, the length H along the radial direction of the eaves portion 15 is set to be equal to or greater than the sum of twice the plate thickness T2 of the body 20 and the misalignment d. That is, in this embodiment, the length H is set to satisfy the following relational expression (2).

H≧2*T2+d...(2)

By setting the length H to satisfy the above relational expression (2), when the first end 13 and the second end 23 are aligned, the end face 23a of the second end 23 is easily brought into contact with the first connection face 16a. The length H is defined as the radial distance between the tip 15a of the first end 13 and the first surface 11. More specifically, the length H is the radial distance between the radially outermost part 15a2 of the tip 15a, which is the radially outermost part, and the surface of the outer diameter side of the first surface 11. That is, in this embodiment, the radially outermost part 15a2 is located radially outward from the surface of the outer diameter side of the first surface 11 by a distance equal to or greater than the total length of twice the plate thickness T2 of the body 20 and the misalignment d.

[1-2-2. Welding process]
After the first end 13 of the head plate 10 and the second end 23 of the body 20 are aligned, a welding process is performed in which the first end 13 and the second end 23 are welded and joined. In the welding process, the welding device W performs arc welding using 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 to the head plate 10 in a direction along the axis AX in the direction in which the head plate 10 and the body 20 press against each other. This makes it easier for the first connection surface 16a and the end surface 23a of the second end 23 to come into contact with each other. In addition, since the first connection surface 16a is open so that the body 20 side is located radially outward, the first connection surface 16a and the end surface 23a press against each other, making it difficult for the head plate 10 and the body 20 to shift in position. Furthermore, the second end 23 is covered from the radially outer side by the second connection surface 16b, which has a smaller opening angle than the first connection surface 16a. Therefore, the second end 23 is less likely to shift radially outward.

The welding device W has a touch sensor (not shown) that detects the position of the tip 15a of the eave portion 15 that is formed around the entire circumference of the first end 13 and that is located vertically above. Using the position information 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 target range R on the eave portion 15. The target range R that is heated by the arc discharge is the inner surface 17c2 of the outer diameter side surface 15b1 of the eave portion 15, which is inside the curve of the third bent portion 17c.

At this time, the eaves portion 15 heated by the arc discharge of the torch W2 melts from the inner surface 17c2, which is the target range R, and fills the gap between the first end 13 and the second end 23. In other words, the eaves portion 15 makes it easier to form a defect-free bead 30 between the first end 13 and the second end 23. In this way, the eaves portion 15 acts like a filler material in the welding process.

In this embodiment, the length L of the eaves portion 15 along the axis AX is at least twice the plate thickness T1, which is the thickness of the first surface portion 11. By making the length L of the eaves portion 15 at least twice the plate thickness T1 as in this embodiment, the eaves portion 15 melted in the welding process is more likely to fill the gap between the first end portion 13 and the second end portion 23. The length L is defined as the distance from the first bent portion 17a to the tip 15a of the first end portion 13 in the direction along the axis AX (axial direction). More specifically, the length L is the distance between the axial tip portion 15a1 of the tip 15a of the eaves portion 15 that is closest to the body 20 and the part of the first bent portion 17a that is farthest from the tip 15a in the direction along the axis AX.

The torch W2 performs an arc discharge on the target range R around the entire circumference of the eaves portion 15, and as shown in FIG. 3, the first end portion 13 and the second end portion 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, and 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, and the first end portion 13 has a first bent portion 17a which expands radially outward from the first surface portion 11, and a second bent portion 17b which is bent in the opposite direction to the first bent portion 17a on the tip 15a side of the first end portion 13 relative to the first bent portion 17a. a second bent portion 17b bent in a direction opposite to that of the second bent portion 17b on the tip 15a side of the second bent portion 17b, and a third bent portion 17c bent in a direction opposite to that of the second bent portion 17b on the tip 15a side of the second bent portion 17b, the second end 23 having a flat shape, and a first connecting surface 16a which is a joint between an outer surface 17a1 of the first bent portion 17a and an inner surface 17b2 of the second bent portion 17b, and an end face 23a of the second end 23 are pressed against each other, and heat is applied from an inner surface 17c2 of the third bent portion 17c to weld the first end 13 and the second end 23.
According to this configuration, the second end 23 can be guided by the first bent portion 17a, the second bent portion 17b, and the third bent portion 17c formed in the first end 13. This makes it easy to align the first end 13 and the second end 23.

Furthermore, as in this embodiment, the second end portion 23 may be configured to be shifted radially outward from the first surface portion 11 by at least the plate thickness T2, which is the thickness of the second end portion 23.
According to this configuration, when aligning the first end 13 and the second end 23, it is possible to prevent the second end 23 from slipping radially inward beyond the first surface portion 11. This makes it easier to align the first end 13 and the second end 23.

Furthermore, as in this embodiment, the inner diameter D2 of the second surface portion 21 may be configured to be greater than the inner diameter D1 of the first surface portion 11 by more than twice the plate thickness T2, which is the thickness of the second end portion 23.
According to this configuration, it becomes easy to dispose the second end 23 by shifting it radially outward by at least the plate thickness T2 with respect to the first surface portion 11. This makes it easy to align the first end 13 and the second end 23.

Also, as in this embodiment, the first bent portion 17a, the second bent portion 17b, and the third bent portion 17c may be configured to be bent at obtuse angles A1, A2, and A3, respectively.
According to this configuration, the first bent portion 17a, the second bent portion 17b, and the third bent portion 17c are formed to bend at angles A1, A2, and A3 that are obtuse angles with respect to the first end portion 13, so that the first end portion 13 can easily guide the end face 23a to the first connecting surface 16a. In particular, when the bending angle A2 of the second bent portion 17b is larger than the bending angle A1 of the first bent portion 17a and the bending angle A3 of the third bent portion 17c satisfies the relational expression (1) as in this embodiment, the end face 23a can be easily guided to the first connecting surface 16a.

Furthermore, as in this embodiment, the distance from the first bent portion 17a to the tip 15a of the first end 13 in the direction of the axis AX of the first surface portion 11, i.e., the length L of the eaves portion 15, may be configured to be more than twice the plate thickness T1 of the first surface portion 11.
According to this configuration, the portion of the first end 13 expanded by the bent portions 17a, 17b, and 17c, i.e., the eaves portion 15, can be used like a filler material, which can suppress the occurrence of defects during welding.

Furthermore, as in this embodiment, the tip 15a of the first end portion 13 may be configured to be positioned radially outward from the first surface portion 11 by a distance greater than the sum of the misalignment d between the second end portion 23 and the first surface portion 11 and twice the plate thickness T2, which is the thickness of the second end portion 23.
With this configuration, the radial distance between the tip 15a of the first end 13 and the first surface portion 11, i.e., the length H, can be made sufficiently large, making it easier to bring the end surface 23a of the second end 23 into contact with the first connection surface 16a of the first end 13.

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 eaves portion 15, i.e., the first end portion 13 where the bent portions 17a, 17b, and 17c are formed, is the head plate 10, and the plate material having the flat second end portion 23 is the body 20, but this is only one example. For example, the body 20 may be formed with an eaves portion, and the first end portion 13 of the head plate 10 may be flat.

In other words, the manufacturing method for a can body is a manufacturing method for a can body in which a head plate 10 and a cylindrical body 20 are welded to produce a can body 1, and the head plate 10 may be one of a first plate material having a first end 13 formed with bent portions 17a, 17b, 17c, and a second plate material having a flat second end 23, and the body 20 may be the other of the first plate material and the second plate material, which is different from the first plate material, and the head plate and the body are welded together using the welding method described in the above embodiment.
According to this configuration, in manufacturing the can body 1, the first end 13 and the second end 23 can be easily aligned when welding the end plate 10 and the body 20 together. This makes it easier to improve the productivity of the can body 1.

In the first embodiment, the gap d between the first surface 11 and the second end 23 is formed by the difference between the inner diameter D1 of the first surface 11 and the inner diameter D2 of the second surface 21, but this is just one example. For example, the inner diameter of the second surface 21 may be D1, and the second end 23 may be machined into a shape that is flat after the second surface 21 is expanded toward the second end 23, thereby providing the gap d.

In the first embodiment, the head plate 10 and the body 20 are described as being made of stainless steel, but this is merely an 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 15a 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 15a 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 material and a second plate material, wherein the first plate material has a cylindrical first surface portion and a first end portion that is an end of the first surface portion, and the second plate material has a cylindrical second surface portion and a second end portion that is an end of the second surface portion, the first end portion is formed with a first bent portion that expands radially outward from the first surface portion, 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, and a third bent portion that is bent in an opposite direction to the second bent portion on the tip side of the second bent portion, the second end portion has a flat shape, and the first end portion and the second end portion are welded together by heating from the third bent portion while a seam between the first bent portion and the second bent portion and an end face of the second end portion are pressed against each other.
As a result, when aligning the first end portion and the second end portion, the second end portion 23 can be guided by the first bent portion, the second bent portion, and the third bent portion formed in the first end portion, making it easier to align the first end portion and the second end portion.

(Technology 2) The welding method according to Technology 1, wherein the second end portion is positioned radially outward from the first surface portion by a distance equal to or greater than the thickness of the second end portion.
This makes it possible to prevent the second end from slipping radially inward beyond the first surface portion when aligning the first end and the second end, making it easier to align the first end and the second end.

(Technology 3) A welding method according to Technology 2, wherein an inner diameter of the second surface portion is greater than an inner diameter of the first surface portion by at least twice the thickness of the second end portion.
This makes it easier to dispose the second end portion radially outwardly shifted from the first surface portion by an amount equal to or greater than the thickness of the second end portion, making it easier to align the first end portion and the second end portion.

(Technology 4) A welding method according to any one of Techniques 1 to 3, wherein the first bent portion, the second bent portion, and the third bent portion are each bent at an obtuse angle.
This forms a first bent portion, a second bent portion, and a third bent portion that bend at an obtuse angle relative to the first end portion, making it easier for the first end portion to guide the end face of the second end portion to the joint between the first bent portion and the second bent portion.

(Technology 5) A welding method described in any one of Technologies 1 to 4, wherein the distance from the first bent portion to the tip of the first end in the axial direction of the first surface portion is at least twice the thickness of the first surface portion.
This allows the portion of the first end portion that is expanded by the first bent portion, the second bent portion, and the third bent portion to be used like a filler metal, thereby making it possible to suppress the occurrence of defects during welding.

(Technology 6) A welding method described in any one of Techniques 1 to 5, wherein the tip of the first end portion is positioned radially outward from the first surface portion by a distance greater than the sum of the misalignment between the second end portion and the first surface portion and twice the thickness of the second end portion.
This allows the radial distance between the tip of the first end portion and the first surface portion to be sufficiently large, making it easier to bring the end face of the second end portion into contact with the joint between the first bent portion and the second bent portion.

(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, 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 allows the first end and the second end to be easily aligned when the head plate and the body are welded together during the manufacture of the can body, which makes it easier to improve the productivity of the can body.

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: End plate 11: First surface portion 13: First end portion 15: Eaves portion 15a: Tip portion 15a1: Axial tip portion 15a2: Outside portion 15b1: Outer diameter side surface 15b2: Inner diameter side surface 16a: First connection surface (joint between first bent portion and second bent portion)
16b second connecting surface 16c third connecting surface 17a first bent portion 17a1 outer surface 17a2 inner surface 17b second bent portion 17b1 outer surface 17b2 inner surface 17c third bent portion 17c1 outer surface 17c2 inner surface 19 dome portion 20 body 21 second surface portion 23 second end portion 23a end surface 30 bead W welding device W1 clamp W2 torch W3 jig d misalignment

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 is formed with a first bent portion that expands radially outward from the first surface portion, 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, and a third bent portion that is bent in an opposite direction to the second bent portion on the tip side of the second bent portion,
the second end has a flat shape;
A welding method in which a joint between the first bent portion and the second bent portion and an end face of the second end portion are pressed against each other, and heat is applied from the third bent portion to weld the first end portion and the second end portion. The second end portion is disposed so as to be shifted toward the outside in the radial direction from the first surface portion by a distance equal to or greater than the thickness of the second end portion.
The welding method according to claim 1. The inner diameter of the second surface portion is greater than the inner diameter of the first surface portion by at least twice the thickness of the second end portion.
The welding method according to claim 2. the first bent portion, the second bent portion, and the third bent portion each bend at an obtuse angle;
The welding method according to claim 1. In the axial direction of the first surface portion, the distance from the first bent portion to the tip of the first end portion is equal to or greater than twice the thickness of the first surface portion.
The welding method according to claim 1. The tip of the first end portion is located radially outward from the first surface portion by a distance greater than the sum of a misalignment between the second end portion and the first surface portion and 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, one of the first plate material and the second plate material different from the other 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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