WO2023248650A1

WO2023248650A1 - Welding method, can body manufacturing method, and welding device

Info

Publication number: WO2023248650A1
Application number: PCT/JP2023/018311
Authority: WO
Inventors: 智也今井; 正朗榊原; 武士物種
Original assignee: 三菱電機株式会社
Priority date: 2022-06-24
Filing date: 2023-05-16
Publication date: 2023-12-28

Abstract

Provided are a welding method and a welding device which use a consumable electrode and can achieve both an increase in welding speed and an enlargement of the dimensional margin for a weld gap. This welding method comprises a preparation step and a welding step. This welding method comprises a preparation step and a welding step. In the welding step, in a state in which a first object (5a) to be welded and a second object (5b) to be welded are disposed such that a portion where a first end (5aa) and a second end (5ba) abut each other is formed, an arc (A) generated by a non-consumable electrode (4) having a center axis (4a) is used to weld said portion. The center axis (4a) of the non-consumable electrode (4) is inclined relative to a normal line (5c) to said portion relating to the surfaces of the first object (5a) to be welded and the second object (5b) to be welded. The center axis (4a) is inclined relative to the normal line (5c) toward the opposite direction of a movement direction of the non-consumable electrode (4) relative to said portion. The inclination angle θ of the center axis (4a) relative to the normal line (5c) is at least 40° but less than 80°.

Description

Welding method, can manufacturing method and welding equipment

The present disclosure relates to a welding method, a can manufacturing method, and a welding device.

Conventionally, welding methods using non-consumable electrodes are known. For example, the TIG (Tungsten Inert Gas) welding method, which generates an arc between a non-consumable tungsten electrode and the workpiece in an inert gas atmosphere, produces high-quality welds with less spatter. Because of this, it is widely used for welding members constituting can bodies or thin plate members. However, welding methods using non-consumable electrodes such as TIG welding have a slower welding speed than MAG (Metal Active Gas) welding and MIG (Metal Inert Gas) welding using consumable electrodes. However, there was a problem in that the dimensional margin for the gap between the objects to be welded (welding gap) was small.

For this reason, for example, in Japanese Patent Application Laid-Open No. 2012-139704, double shielding gas is flowed from the nozzle of a welding torch equipped with a tungsten electrode to increase the arc energy density, arc directionality, etc., and to increase the welding speed. We are trying to speed it up.

Japanese Patent Application Publication No. 2012-139704

Although the welding method disclosed in Japanese Patent Application Laid-open No. 2012-139704 described above can increase the welding speed, it does not solve the problem of small dimensional margin for the weld gap. As described above, with conventional welding methods using non-consumable electrodes, it has been difficult to simultaneously increase the welding speed and increase the dimensional margin for the weld gap.

Therefore, the present disclosure provides a welding method and a welding device using a consumable electrode, which can both increase the welding speed and expand the dimensional margin for the weld gap, and further provide a can body using the same. The purpose is to provide a manufacturing method.

A welding method according to the present disclosure includes a preparing step and a welding step. In the preparing step, a first workpiece having a first end and a second workpiece having a second end are prepared. In the welding process, the first and second objects to be welded are arranged so that a butted portion of the first end and the second end is formed, and a non-consumable material having a central axis is The above parts are welded using an arc generated by an electrode. In the step of welding, the parts are welded while the non-consumable electrode is moved relative to the parts. The central axis of the non-consumable electrode is inclined with respect to the normal to the surfaces of the first and second objects to be welded. The central axis is inclined with respect to the normal in a direction opposite to the direction of movement of the non-consumable electrode relative to the portion. The angle of inclination of the central axis with respect to the normal is 40° or more and less than 80°.

A method for manufacturing a can body according to the present disclosure is a method for manufacturing a can body using the above welding method. In the above preparation step, a cylindrical body portion constituting a can body is prepared as the first object to be welded. In the preparation step, the end plate of the can body is prepared as the second object to be welded. The first end is an annular end in the extending direction of the body. The second end portion is the outer peripheral portion of the end plate portion. In the welding step, the body and the end plate are arranged so that a portion where the end of the body and the outer periphery of the end plate abut against each other is formed. While the non-consumable electrode is fixed, the body part and the end plate part are welded while being rotated about a central axis of rotation extending along the extending direction of the body part. The normal line is a straight line that is perpendicular to the rotation axis and connects the rotation center axis and the tip of the non-consumable electrode.

A welding device according to the present disclosure includes a non-consumable electrode, a power source, and a control unit. The non-consumable electrode has a central axis. A power source powers the non-consumable electrodes. The control unit controls the attitude of the central axis of the non-consumable electrode with respect to the workpiece.

According to the above, there is a welding method and welding device using a consumable electrode that can both increase the welding speed and expand the dimensional margin for the weld gap, and also manufacture a can body using the same. method is obtained.

1 is a schematic diagram showing the configuration of a welding device according to Embodiment 1. FIG. 1 is a schematic diagram for explaining a welding method according to Embodiment 1. FIG. 3 is a flowchart of the welding method shown in FIG. 2. FIG. 7 is a schematic diagram for explaining a welding method according to a second embodiment. 5 is a schematic diagram seen from the direction indicated by the arrow in FIG. 4. FIG. FIG. 6 is a schematic diagram for explaining a modification of the welding method shown in FIGS. 4 and 5. FIG. FIG. 3 is a schematic diagram showing the configuration of a welding device according to Embodiment 3. FIG. 7 is a schematic diagram for explaining a welding method according to Embodiment 3. 7 is a flowchart of a method for manufacturing a can according to Embodiment 4. FIG. 10 is a schematic diagram for explaining a method of manufacturing the can body shown in FIG. 9. FIG. 10 is a schematic diagram for explaining a method of manufacturing the can body shown in FIG. 9. FIG. 10 is a schematic diagram for explaining a method of manufacturing the can body shown in FIG. 9. FIG. FIG. 7 is a schematic diagram showing the configuration of a welding device according to Embodiment 5. FIG. 7 is a schematic diagram showing the configuration of a welding device according to a sixth embodiment. FIG. 7 is a schematic diagram showing the configuration of a welding device according to a sixth embodiment. FIG. 7 is a schematic diagram showing the configuration of a welding device according to Embodiment 7. 3 is a graph showing the relationship between the inclination angle of the central axis of a non-consumable electrode and the maximum arc pressure. It is a graph showing the relationship between arc length and maximum arc pressure. It is a graph showing the temperature distribution at the time of arc extinguishing from the tip of the pool for each inclination angle.

Hereinafter, embodiments of the present disclosure will be described. In addition, the same reference numerals are given to the same structure, and the description thereof will not be repeated.

Embodiment 1.
<Configuration of welding equipment>
As shown in FIG. 1, a welding device 1 according to the present embodiment is a welding device that performs the so-called TIG welding method, and includes a welding torch 2, a power source 6, a control section 7, and a drive section 8. Prepare for the Lord. Welding torch 2 includes a non-consumable electrode 4 and a nozzle 3. The non-consumable electrode 4 is, for example, a tungsten electrode. As the material for the non-consumable electrode 4, pure tungsten or a tungsten alloy can be used. As the tungsten alloy, for example, tungsten containing several percent of an alloying element such as lanthanum, cerium, or thorium can be used. As shown in FIG. 2, the non-consumable electrode 4 has a central axis 4a. A non-consumable electrode 4 is arranged inside the nozzle 3. Note that, when the non-consumable electrode 4 has a rod-like shape, the central axis 4a of the non-consumable electrode 4 extends along the extending direction of the rod-shaped non-consumable electrode 4, and the central axis 4a of the non-consumable electrode 4 is an imaginary axis passing through the center of a cross section perpendicular to the extending direction of .

The nozzle 3 supplies shielding gas around the non-consumable electrode 4. The nozzle 3 is connected to a shielding gas supply source (not shown). Shielding gas is stored in the shielding gas supply source. The shielding gas supplied around the non-consumable electrode 4 from the nozzle 3 is blown toward the workpiece 5 from around the non-consumable electrode 4 . As the shielding gas, any gas can be used as long as it is an inert gas used in TIG welding. For example, argon gas, helium gas, or a mixed gas thereof can be used as the shielding gas. Further, as the shielding gas, a mixed gas obtained by mixing about several percent of an active gas with an inert gas as described above may be used. As the active gas constituting the mixed gas, for example, oxygen gas, nitrogen gas, or hydrogen gas can be used.

A power source 6 supplies power to the non-consumable electrode 4 of the welding torch 2. The negative terminal of the power source 6 is connected to the non-consumable electrode 4 of the welding torch 2. A positive terminal of the power source 6 is connected to the workpiece 5. As a result, as shown in FIG. 2, an arc A, which is a TIG arc, is generated between the non-consumable electrode 4 and the workpiece 5.

The drive unit 8 arbitrarily changes the attitude and position of the welding torch 2 with respect to the workpiece 5. By controlling the drive unit 8, the control unit 7 can control the direction of the central axis 4a of the non-consumable electrode 4 with respect to the workpiece 5. Specifically, as shown in FIG. 2, the drive unit 8 controls the attitude of the welding torch 2 so that the central axis 4a of the non-consumable electrode 4 is inclined with respect to the normal 5c of the workpiece 5. do. As the drive unit 8, any configuration can be adopted. For example, a multi-axis robot arm or the like can be used as the drive unit 8.

Note that it is only necessary that the relative position and posture of the non-consumable electrode 4 with respect to the workpiece 5 can be changed. For example, while the welding torch 2 including the non-consumable electrode 4 is fixed, it is possible to change the position and posture of the non-consumable electrode 4 relative to the workpiece 5. The holding member may be moved relative to the welding torch 2. In this case, the welding device 1 includes a moving section that moves the holding member. Although any configuration can be adopted as the moving unit, for example, an XY stage or the like may be used.

The material of the object to be welded 5 is not particularly limited. Examples of the material of the object to be welded 5 include steel materials such as carbon steel, stainless steel, aluminum alloys, magnesium alloys, nickel alloys, copper alloys, titanium alloys, and the like.

<Welding method>
In the welding method using the welding apparatus 1 shown in FIG. 1, as shown in FIG. 3, a preparation step (S1) is first performed. In this step (S1), as shown in FIG. 2, a first workpiece 5a having a first end 5aa and a second workpiece 5b having a second end 5ba are prepared.

Next, a welding step (S2) is performed. In this step (S2), as shown in FIG. 2, the first workpiece 5a and the second workpiece 5b are formed such that a portion where the first end 5aa and the second end 5ba butt each other is formed. and place it. In this state, the above portions are welded using an arc A generated by a non-consumable electrode 4 having a central axis 4a. This will be explained in detail below.

In the step (S2), the first workpiece 5a and the second workpiece 5b are plate materials, and the end face of the first end 5aa and the end face of the second end 5ba are butted to form a butt joint. Become. At this time, the butted end surfaces may contact each other, but a gap (welding gap) may be formed between the two end surfaces.

Welding is performed with the first workpiece 5a and the second workpiece 5b arranged as described above. First, shielding gas is sent to the nozzle 3 of the welding torch 2 from a shielding gas supply source (not shown). Next, the power source 6 is operated to apply a welding current between the non-consumable electrode 4 and the object to be welded 5. As a result, arc A is generated as shown in FIG. Next, the welding torch 2 is moved in a direction (welding direction) along a portion where the end surface of the first end 5aa and the end surface of the second end 5ba are butted against each other. As a result, the non-consumable electrode 4 moves relative to the above-mentioned part, and the said part is welded by the arc A. Specifically, the arc A melts the surface of the object to be welded 5 (the surface of the portion where the first end 5aa and the second end 5ba are butted together), and a molten pool P is formed. Thereafter, when the welding torch 2 moves, the molten pool P is cooled and solidified to become the weld metal M. As a result, the first workpiece 5a and the second workpiece 5b are welded by the weld metal M.

At this time, welding may be performed by fixing the welding torch 2 and moving the workpiece 5 with respect to the welding torch 2. Furthermore, in the process described above, the welding torch 2 or the workpiece 5 as the base metal is moved after the arc A is generated, but the arc A is generated while the welding torch 2 or the workpiece 5 is moved. You may let them.

In the step (S2), as shown in FIGS. 1 and 2, the non-consumable electrode 4 The central axis 4a is inclined. Note that the normal line 5c is the normal line to the surface of the first workpiece 5a (the surface facing the welding torch 2) at the part where the first workpiece 5a and the second workpiece 5b are butted together. You may. The direction of inclination of the central axis 4a is opposite to the direction of movement of the welding torch 2 relative to the normal line 5c at the portion where the first workpiece 5a and the second workpiece 5b abut against each other. The inclination angle θ of the central axis 4a with respect to the normal line 5c is 40° or more and less than 80°. Therefore, as shown in FIG. 2, the arc A is formed to extend in a direction oblique to the surface of the workpiece 5. Further, the arc A has a shape that spreads further forward than the molten pool P in the direction in which welding progresses (the direction in which the welding torch 2 moves).

Further, the electrode protrusion length L (see FIG. 2), which is the distance from the tip of the nozzle 3 of the welding torch 2 to the tip of the non-consumable electrode 4, is not particularly limited. The electrode protrusion length L is preferably set to 20 mm or less. This is because there is a concern that the longer the electrode protrusion length L becomes, the worse the gas shielding properties will be, making welding unstable, or the more likely the welding part will be oxidized. However, if the configuration of the nozzle 3 is such that laminar shielding gas can be sprayed over a long distance, the electrode protrusion length L may be set to 20 mm or more.

<Effect>
The welding method according to the present disclosure includes a step of preparing (S1) and a step of welding (S2). In the preparing step (S1), a first workpiece 5a having a first end 5aa and a second workpiece 5b having a second end 5ba are prepared. In the welding step (S2), the first workpiece 5a and the second workpiece 5b are arranged so that a portion where the first end 5aa and the second end 5ba are butted together is formed, The above parts are welded using an arc A generated by a non-consumable electrode 4 having a central axis 4a. In the welding step (S2), the above-mentioned parts are welded while moving the non-consumable electrode 4 relative to the above-mentioned parts. The central axis 4a of the non-consumable electrode 4 is inclined with respect to the normal line 5c at the above-mentioned portion with respect to the surfaces of the first workpiece 5a and the second workpiece 5b. The central axis 4a is inclined with respect to the normal line 5c in a direction opposite to the direction of movement of the non-consumable electrode 4 with respect to the portion. The inclination angle θ of the central axis 4a with respect to the normal line 5c is 40° or more and less than 80°.

In this way, as shown in FIG. 2, the arc A is formed to extend in a direction inclined with respect to the surfaces of the first workpiece 5a and the second workpiece 5b. Further, the arc A has a shape that spreads further forward than the molten pool P in the direction in which welding progresses (the direction in which the welding torch 2 including the non-consumable electrode 4 moves). Therefore, it is possible to increase the welding current supplied to the non-consumable electrode 4 and improve the welding speed while suppressing the occurrence of burn-through defects and the like. Further, by preheating the region in front of the molten pool P in the direction in which welding progresses by the arc A, the dimensional margin for the welding gap can be expanded. This will be explained in more detail below.

In welding using the above-mentioned non-consumable electrode 4 and shielding gas, for example, TIG welding, as arc A is generated, a plasma airflow due to the surrounding shielding gas is generated in the direction along the central axis 4a of the non-consumable electrode 4. do. The plasma airflow is blown onto the workpiece 5 to be welded. The plasma airflow collides with the object to be welded 5, and the traveling direction of the plasma airflow changes to a direction along the surface of the object to be welded 5 (in the surface direction). At this time, as the traveling direction of the plasma airflow is changed, a force (arc force) acts on the workpiece 5 along the original traveling direction of the plasma airflow.

It is known that the arc force increases as the welding current supplied to the non-consumable electrode 4 increases. In order to increase the welding speed, it is necessary to increase the amount of heat input by the arc A in order to maintain the welding heat input per unit length applied to the workpiece 5. In other words, it is necessary to increase the welding current. In this case, as the welding current increases, the arc force also increases. When the arc force increases, the force that pushes the molten pool P downward in the thickness direction (plate thickness direction) of the workpiece 5 to be welded increases. As a result, defects in which the molten pool P drops downward (melt-through defects) are likely to occur. Further, such burn-through defects tend to occur more easily when the thickness (plate thickness) of the welded object 5 is thinner.

Here, in the welding method according to the first embodiment, the welding torch 2 and the non-consumable electrode 4 are tilted in a direction opposite to the direction in which welding progresses. Further, the inclination angle θ, which is the angle between the central axis 4a of the non-consumable electrode 4 and the normal line 5c of the workpiece 5, is set in a range of 40° or more and less than 80°. Therefore, the arc force that acts to push down the molten pool P downward in the plate thickness direction can be reduced.

For example, according to an experiment described later, when the welding current value is 100 A and the inclination angle θ is increased from 0° to 40°, the downward arc force in the plate thickness direction is halved. Further, when the inclination angle θ is set to 0° and the value of the welding current is increased from 100 A to 200 A, the downward arc force in the plate thickness direction increases approximately 2.2 times. However, by setting the inclination angle θ to 40° or more, the arc force when the welding current value is 200A is equal to or less than the arc force when the inclination angle θ is 0° and the welding current value is 100A. can be reduced to Further, when the inclination angle θ is 80° or more, the arc A generated between the non-consumable electrode 4 and the workpiece 5 to be welded becomes unstable, and welding quality may deteriorate or welding may not be possible. From the above, by setting the inclination angle θ to 40° or more and less than 80°, it is possible to suppress the arc force that acts in a downward direction (downward) on the molten pool P during welding. Therefore, the welding current can be increased without causing burn-through defects, and as a result, the welding speed can be increased.

Here, if the inclination angle θ is increased, the arc force in the downward direction is reduced, but the arc A tends to become unstable. Therefore, considering the reduction of the arc force in the downward direction and the stability of the arc A, it is preferable that the inclination angle θ is set to 45° or more and 75° or less.

Further, according to the welding method according to the first embodiment, when welding thin plate materials having a thickness of 0.1 mm or more and 2 mm or less as the first workpiece 5a and the second workpiece 5b, It is possible to increase the dimensional margin for the gap (welding gap) created when the first workpiece 5a and the second workpiece 5b are butted together.

Here, when welding thin plate materials, if the welding gap is large, there will be a shortage of material to fill the welding gap. Therefore, even if the molten metals of the first welded object 5a and the second welded object 5b are not joined together, or even if the molten metals are joined together to form a molten pool P, burn-through defects due to arc force may occur. There are concerns that such problems may occur. Therefore, for example, in a butt joint by TIG welding that does not use a welding wire, the maximum allowable welding gap is about 20% of the plate thickness of the workpiece 5 to be welded. Therefore, when the thickness of the workpiece 5 is 2 mm or less, the welding gap is assumed to be 0.4 mm or less.

Furthermore, when actually manufacturing a product by welding, it is necessary to consider thermal deformation of the welded object 5 due to welding. Therefore, it is difficult to eliminate the welding gap. Therefore, a welding method with a large dimensional margin for the welding gap is desired.

In the welding method according to the first embodiment, the welding torch 2 is tilted in the opposite direction to the direction in which welding progresses, and the tilt angle θ is set in the range of 40° or more and less than 80°, as shown in FIG. has been done. Therefore, the generated arc A has a shape that spreads farther forward than the molten pool P in the direction in which welding progresses. Therefore, the effect of preheating the front region of the molten pool P can be obtained. When the front region is preheated, the temperature of the weld object 5 in the front region increases, and the weld object 5 (the first weld object 5a and the second weld object 5b) thermally expands in a direction that reduces the welding gap. . As a result, it is possible to suppress the occurrence of problems such as the objects to be welded 5 not being joined or the occurrence of burn-through defects. This makes it possible to increase the dimensional margin for the welding gap.

The welding device 1 according to the present disclosure includes a non-consumable electrode 4, a power source 6, and a control unit 7. Non-consumable electrode 4 has a central axis 4a. A power source 6 supplies power to the non-consumable electrode 4. The control unit 7 controls the attitude of the central axis 4a of the non-consumable electrode 4 with respect to the workpiece 5. In this case, the welding method described above can be easily carried out using the welding device 1.

Here, if the inclination angle θ, which is the angle between the central axis 4a of the non-consumable electrode 4 and the normal line 5c of the workpiece 5, is increased, the depth of the molten pool P formed by the arc A becomes shallower. . Therefore, in the welding apparatus 1 according to the first embodiment, it is preferable that the thickness of the workpiece 5 to be welded is 2 mm or less. Although it is possible to use a workpiece 5 with a plate thickness larger than 2 mm, the depth of the molten pool P becomes shallow, and it is difficult to completely melt the workpiece 5 in the entire thickness direction of the workpiece 5. may be difficult.

Embodiment 2.
<Welding method>
As shown in FIGS. 4 and 5, the welding method according to the second embodiment basically has the same configuration as the welding method shown in FIGS. 2 and 3, and can obtain similar effects. However, the shape of the workpiece 5 is different from the welding method shown in FIGS. 2 and 3. That is, in the welding method shown in FIGS. 4 and 5, the ends of the first workpiece 5a and the second workpiece 5b are bent as shown in FIG. Note that FIG. 5 shows the end portions of the first workpiece 5a and the second workpiece 5b viewed from the direction shown by the arrow 10 in FIG. The first end portion 5aa of the first workpiece 5a includes a bent portion 5aa1 and an extending portion 5aa2. The bent portion 5aa1 is bent to have an L-shape in a cross section perpendicular to the moving direction of the welding torch 2. The extending portion 5aa2 extends from the bent portion 5aa1 in a direction along the normal line 5c (see FIG. 4). The second end portion 5ba of the second workpiece 5b includes a bent portion 5ba1 and an extended portion 5ba2. The bent portion 5ba1 is bent to have an L-shape in the cross section. The extending portion 5ba2 extends from the bent portion 5ba1 in a direction along the normal line 5c (see FIG. 4). The bent portion 5ba1 of the second end portion 5ba is arranged so as to face the bent portion 5aa1 of the first end portion 5aa. The extending portion 5ba2 of the second end portion 5ba is arranged so as to face the extending portion 5aa2 of the first end portion 5aa. In this way, the portion where the first workpiece 5a and the second workpiece 5b are butted has a bow joint shape. The welding method described above can be performed using the welding apparatus 1 according to the first embodiment.

As shown in FIG. 4, when welding the workpiece 5, the arc A is formed so as to go toward the extending portion 5aa2 of the first end 5aa and the extending portion 5ba2 of the second end 5ba. . The extending portions 5aa2 and 5ba2 are melted by the arc A and flow downward, thereby becoming part of the molten pool P. By moving the welding torch 2 in the direction approaching the extension parts 5aa2 and 5ba2, the extension parts 5aa2 and 5ba2 are sequentially melted and a molten pool P is formed.

Note that, as shown in FIG. 6, only one of the first end 5aa and the second end 5ba may be bent. In FIG. 6, only the first end portion 5aa includes a bent portion 5aa1 and an extension portion 5aa2. The second end portion 5ba is not bent. The end surface of the second end portion 5ba is arranged to face the bent portion 5aa1 of the bent first end portion 5aa.

<Effect>
In the above welding method, at the portion where the first end 5aa and the second end 5ba are butted together, one of the first end 5aa and the second end 5ba (the first end 5aa in FIG. 6) is It may also include a bent portion 5aa1 and an extended portion 5aa2. The bent portion 5aa1 may be bent to have an L-shape in a cross section perpendicular to the movement direction. The extending portion 5aa2 may extend from the bent portion 5aa1 in a direction along the normal line 5c. The other of the first end 5aa and the second end 5ba (the second end 5ba in FIG. 6) may be arranged to face the bent portion 5aa1.

In the welding method described above, in the above-mentioned portion where the first end 5aa and the second end 5ba are butted together, the other of the first end 5aa and the second end 5ba (the second end 5ba in FIG. 5) is , may include a bent portion 5ba1 and an extended portion 5ba2. The bent portion 5ba1 may be bent to have an L-shape in the cross section. The extending portion 5ba2 may extend from the bent portion 5ba1 in a direction along the normal line 5c. The bent portion 5ba1 of the second end portion 5ba may be arranged so as to face the bent portion 5aa1 of the first end portion 5aa. The extending portion 5ba2 of the second end portion 5ba may be arranged so as to face the extending portion 5aa2 of the first end portion 5aa.

In this case, the same effects as the welding method according to Embodiment 1 can be obtained, and the dimensional margin of the welding gap can be further increased. This will be explained in more detail below.

In the case of a joint (butt joint) having a first end 5aa or a second end 5ba with an L-shaped cross-section as in the second embodiment, the arc A preheats the front region of the molten pool P. As a result, the first end 5aa or the second end 5ba having an L-shaped cross section is thermally deformed. Specifically, the first end 5aa or the second end 5ba is thermally deformed in a direction in which residual stress is released when the first end 5aa or the second end 5ba is processed into an L-shape. . As a result, the thermal deformation causes the first end 5aa or the second end 5ba to deform so that the degree of L-shaped bending becomes gentle. In a butt joint, the weld gap becomes smaller due to the deformation of the L-shape in a direction where the degree of bending becomes gentler. Therefore, the inclination angle θ, which is the angle between the central axis 4a of the non-consumable electrode 4 of the welding torch 2 and the direction of the normal line 5c of the workpiece 5, is set in the range of 40° or more and less than 80°, and the L-shaped By using a butt joint having the first end 5aa or the second end 5ba, the dimensional margin for the welding gap can be further increased than in the welding method according to the first embodiment.

The angle between the surface of the molten part in the extension parts 5aa2, 5ba2 at the first end 5aa or second end 5ba of the L-shape during welding and the normal 5c shown in FIG. 4 is about 0°. (The surface of the molten part extends almost vertically) is considered. On the other hand, it is also possible that the angle is about 80°. For example, the angle changes depending on welding conditions such as the inclination angle θ, which is the angle between the central axis 4a of the non-consumable electrode 4 and the normal line 5c of the workpiece 5, welding current, welding speed, etc. Note that it is preferable to avoid a situation where the angle is approximately 0°.

According to the welding method according to the second embodiment as described above, compared to the case of using a butt joint that does not have the L-shaped first end 5aa or second end 5ba, the dimensional margin for the welding gap can be further increased. can be made larger. Further, compared to a method of increasing the dimensional margin of the welding gap using a welding rod or welding wire for a butt joint, the welding speed can be made higher.

Embodiment 3.
<Configuration of welding equipment>
As shown in FIG. 7, the welding device 1 according to the third embodiment basically has the same configuration as the welding device 1 shown in FIG. The welding apparatus 1 differs from the welding apparatus 1 shown in FIG. 1 in that it further includes a section 9. The welding apparatus 1 shown in FIG. 7 includes a detection section 9 connected to a control section 7. The detection unit 9 detects displacement of the workpiece 5 to be welded.

As the detection unit 9, for example, a sensor 9a that directly measures the displacement of the object to be welded 5 can be used. As the sensor 9a, for example, a position sensor such as a laser displacement meter, an imaging device that acquires image data to measure the displacement of the object to be welded 5 based on image data, or the like can be used. The position of the top surface of the extending portions 5aa2, 5ba2 of the first end 5aa or the second end 5ba shown in FIG. 8, for example, may be detected by the sensor 9a. In this case, it is preferable that the sensor 9a be placed at a position where it is not affected by the arc A. As shown in FIG. 8, the arc A has a shape that spreads toward the front in the welding progress direction (direction from the non-consumable electrode 4 toward the extension parts 5aa2 and 5ba2 in FIG. 8). Therefore, when measuring the displacement of the workpiece 5 near the welding part, it is necessary to consider the influence of the arc A. For example, a filter that blocks light from the arc A may be installed on the sensor 9a.

Further, as the detection unit 9, a voltage sensor 9b that measures an arc voltage indicating the state of the arc A can be used. When the object to be welded 5 is displaced, the distance between the object to be welded 5 and the non-consumable electrode 4 changes, resulting in a change in the arc voltage. Therefore, the displacement of the object to be welded 5 can be measured indirectly by the arc voltage.

The control unit 7 controls the drive unit 8 according to the displacement of the workpiece 5 detected by the detection unit 9. As a result, the drive unit 8 can change the position of the welding torch 2 with respect to the workpiece 5. Therefore, the position of the welding torch 2, that is, the position of the non-consumable electrode 4 can be adjusted.

<Welding method>
The welding method using the welding device 1 shown in FIG. 7 basically has the same configuration as the welding method shown in FIG. ), the method of controlling the position of the non-consumable electrode 4 of the welding torch 2 is different from the welding method shown in FIG. That is, in the welding method shown in FIG. 8, during welding, the distance H1 from the bent portions 5aa1, 5ba1 to the non-consumable electrode 4 in the direction of the normal line 5c is from the bent portions 5aa1, 5ba1 to the extending portions 5aa2, 5ba2. The position of the welding torch 2 is controlled so that the distance to the top surface of the welding torch 2 is at least H2. That is, the position of the welding torch 2 is adjusted so that the distance h from the top surface of the extension parts 5aa2, 5ba2 to the non-consumable electrode 4 in the direction along the normal line 5c is greater than or equal to zero, preferably greater than zero. be done.

The position of the welding torch 2 is controlled by a drive unit 8 based on a signal from a control unit 7. At this time, the detection unit 9 detects the displacement of the extension portions 5aa2 and 5ba2. A signal indicating the displacement of the extension portions 5aa2 and 5ba2 is transmitted from the detection unit 9 to the control unit 7. Based on the signal, the control unit 7 adjusts the distance H1 from the bending parts 5aa1 and 5ba1 to the non-consumable electrode 4 so as to maintain the state of the arc A appropriately.

As shown in FIG. 7, since the non-consumable electrode 4 is arranged so as to be inclined with respect to the normal line 5c, the arc A is directed diagonally upward with respect to the extending portions 5aa2 and 5ba2 of the workpiece 5. sprayed from. The portions of the extension portions 5aa2 and 5ba2 melted by the arc A become part of the molten pool P.

<Effect>
In the above welding method, the distance H1 from the bent portions 5aa1, 5ba1 to the non-consumable electrode 4 is greater than or equal to the distance H2 from the bent portions 5aa1, 5ba1 to the top surfaces of the extension portions 5aa2, 5ba2 in the direction of the normal line 5c. You can leave it there. In this case, since the non-consumable electrode 4 is arranged at a position sufficiently away from the workpiece 5 to be welded, the arc force that acts to push the molten pool P downward in the thickness direction can be reduced.

In the welding method described above, in the welding step (S2), the distance H1 from the bent portions 5aa1, 5ba1 to the non-consumable electrode 4 may be adjusted according to the displacement of the extension portions 5aa2, 5ba2. In this case, in the welding step (S2), even if the extending parts 5aa2, 5ba2 of the welded object 5 are displaced due to thermal deformation, the non-consumable electrode 4 and the extending parts 5aa2, 5ba2 of the welded object 5 The distance between the two can be maintained within an appropriate range. As a result, the welding quality in the welding step (S2) can be stabilized.

The welding apparatus 1 may include a detection section 9 that detects the displacement of the object to be welded 5. The control unit 7 may control the position of the non-consumable electrode 4 according to the displacement of the workpiece 5 detected by the detection unit 9. As a result, by using the welding apparatus 1, the welding quality can be stabilized even if the workpiece 5 is thermally deformed during welding.

Embodiment 4.
<Method for manufacturing can body>
A method for manufacturing a can body according to this embodiment will be described below. As shown in FIG. 9, in the can manufacturing method according to the present embodiment, a step (S10) of preparing can parts is first performed. This step (S10) corresponds to the preparing step (S1) shown in FIG. In the above step (S10), as shown in FIG. 10, the body portion 21 and end plate portion 22 that constitute the can body 20 are prepared. Note that the can body 20 is, for example, a metal hot water storage tank in a hot water storage type water heater. The body portion 21 has a cylindrical shape. The body portion 21 corresponds to the first object to be welded 5a. The end plate portion 22 has a U-shaped or semicircular cup shape in cross section. The mirror plate portion 22 corresponds to the second object to be welded 5b. An annular end portion 21a in the extending direction of the body portion 21 corresponds to the first end portion 5aa in FIGS. 4 and 5. The outer peripheral portion 22a of the end plate portion 22 corresponds to the second end portion 5ba in FIGS. 4 and 5. The end portion 21a of the body portion 21 and the outer peripheral portion 22a of the mirror plate portion 22 are formed with bent portions and extended portions as shown in FIGS. 4 and 5.

Next, a welding step (S20) is performed. This step (S20) corresponds to the welding step (S2) shown in FIG. 3. In the above step (S20), as shown in FIG. 10, the body part 21 and the end plate part 22 are assembled so that a portion where the end part 21a of the body part 21 and the outer circumferential part 22a of the end plate part 22 butt each other is formed. Placed. The portion where the end portion 21a and the outer circumferential portion 22a butt each other is a joint. In addition, the bending part and the extending part may not be formed in the end part 21a and the outer peripheral part 22a, and the said part may serve as a simple butt joint.

The body part 21 and the mirror plate part 22 are arranged so that the rotation center axis 21b (see FIG. 11) of the body part 21 extends along the horizontal direction. The two mirror plate parts 22 are arranged so as to sandwich the body part 21 therebetween. A jig 25 is installed on the end plate portion 22. Stress is applied to the end plate portion 22 by the jig 25 in the direction shown by the arrow in FIG. In this state, the welding torch 2 is placed so as to face the portion where the end portion 21a of the body portion 21 and the outer peripheral portion 22a of the mirror plate portion 22 are butted against each other.

As shown in FIGS. 10 and 11, a welding torch 2 containing a non-consumable electrode 4 is fixed. In this state, while rotating the body part 21 and the mirror plate part 22 in the direction shown by the arrow in FIG. 21a and the outer circumferential portion 22a (the portion to be welded) are welded. At this time, consider a straight line 20a that is perpendicular to the rotation center axis 21b and connects the rotation center axis 21b and the tip of the non-consumable electrode 4. The straight line 20a corresponds to the normal line 5c shown in FIG. 4. The central axis 4a of the non-consumable electrode 4 is inclined with respect to the straight line 20a in the direction opposite to the moving direction of the non-consumable electrode 4 (the direction indicated by the arrow in FIG. 11). The inclination angle θ of the central axis 4a with respect to the straight line 20a corresponding to the normal line 5c is 40° or more and less than 80°. In this way, the curved connection portion between the body portion 21 and the end plate portion 22 (the portion where the end portion 21a of the body portion 21 and the outer peripheral portion 22a of the end plate portion 22 are butted together) can be reliably welded. As a result, the can body 20 in which the body portion 21 and the end plate portion 22 are joined can be obtained.

Note that in the above step (S20), the position of the welding torch 2 may be determined as shown in FIG. 12. That is, consider a line segment 20b that connects the rotation center axis 21b and the apex 21c located at the uppermost position of the body portion 21 when viewed from the direction along the rotation center axis 21b of the body portion 21. The non-consumable electrode 4 of the welding torch 2 is located at a position on the outer periphery side of the body part 21 and the end plate part 22 and overlaps the line segment 20b, or at a position further than the line segment 20b in the rotational direction of the body part 21 and the end plate part 22. It is located in the area located on the front side. From a different point of view, the non-consumable electrode 4 extends from the topmost vertex 21c of the body part 21 to the front side in the rotational direction of the body part 21 and the mirror plate part 22 (the direction indicated by the arrow in FIG. 12). placed in the area.

In the above step (S20), the welding method shown in Embodiment 2 is applied as described above, but even if the welding method shown in

Embodiment

1 or 3 is applied. good.

<Effect>
A method for manufacturing the can body 20 according to the present disclosure is a method for manufacturing the can body 20 using the above welding method. In the preparation step (S1), the cylindrical body portion 21 constituting the can body 20 is prepared as the first object to be welded 5a. In the preparation step (S1), the end plate portion 22 of the can body 20 is prepared as the second object to be welded 5b. The first end portion 5aa is an annular end portion 21a in the extending direction of the body portion 21. The second end portion 5ba is the outer peripheral portion 22a of the mirror plate portion 22. In the welding step (S2), the body part 21 and the end plate part 22 are arranged so that a portion where the end part 21a of the body part 21 and the outer peripheral part 22a of the end plate part 22 butt each other is formed. While the non-consumable electrode 4 is fixed, the body part 21 and the end plate part 22 are welded while being rotated about a rotation center axis 21b extending along the direction in which the body part 21 extends. The normal line 5c is a straight line 20a that is perpendicular to the rotation center axis 21b and connects the rotation center axis 21b and the tip of the non-consumable electrode 4.

In this way, the connection portion between the body portion 21 and the end plate portion 22 can be a high-quality welded portion.

In the above method for manufacturing a can body, in the welding step (S2), the body portion 21 and the end plate portion 22 may be arranged so that the rotation center axis 21b extends along the horizontal direction. When viewed from the direction along the rotation center axis 21b, the non-consumable electrode 4 is arranged in a region on the front side in the rotation direction of the body part 21 and the end plate part 22 from the topmost apex 21c of the body part 21. You can leave it there.

In this case, the flow of the melt in the molten pool P (see FIG. 4) formed by welding is stabilized. As a result, a uniform weld bead can be obtained.

Embodiment 5.
<Configuration of welding equipment>
As shown in FIG. 13, the welding device 1 according to the fifth embodiment basically has the same configuration as the welding device 1 shown in FIG. The configuration of the section 8 differs from the welding apparatus 1 shown in FIG. 1 in that it includes a linear guide 30 and a guide section 31. In FIG. 16, a structure near the welding torch 2 in the welding apparatus 1 is shown. In the welding apparatus 1 shown in FIG. 13, the guide portion 31 is arranged so as to be in contact with the workpiece 5 to be welded. Welding torch 2 is connected to linear guide 30. The linear guide 30 is connected to a guide section 31. The linear guide 30 adjusts the position of the welding torch 2 by moving during welding. Specifically, as will be described later, the guide section 31 detects the displacement of the workpiece 5 to be welded, and the linear guide 30 moves in accordance with the displacement. As the linear guide 30 moves, the welding torch 2 connected to the linear guide 30 also moves. This will be explained in detail below.

The linear guide 30 includes a linear guide rail 30a and a linear guide block 30b. A torch holder 32 is connected to the linear guide block 30b via, for example, a flat plate 33. Welding torch 2 is connected to torch holder 32 . The linear guide rail 30a is connected to the drive section 8 (see FIG. 1).

The guide section 31 includes a guide roller 31a and a bracket 31b. As the bracket 31b, a member having an L-shaped cross section as shown in FIG. 13 may be used, but a member having any other arbitrary shape may also be used. The guide portion 31 is connected to a flat plate 33 connected to the linear guide block 30b. In other words, the guide portion 31 and the welding torch 2 are connected to the linear guide block 30b by the same flat plate 33. In FIG. 13, the bracket 31b is included in the configuration of the guide portion 31, but the guide roller 31a may be directly connected to the flat plate 33 depending on the case. In this case, the guide portion 31 consists of only the guide roller 31a. As the guide roller 31a, for example, a ball roller having a rotatable ball at its tip can be used. The guide roller 31a is arranged so as to be in contact with the workpiece 5 to be welded. Therefore, other members than the ball roller can be used as long as they can be slid against the workpiece during welding.

<Welding method>
The welding method using the welding device 1 shown in FIG. 13 basically has the same configuration as the welding method shown in FIG. 4 or FIG. In step (S2), the method of controlling the position of the non-consumable electrode 4 of the welding torch 2 is different from the welding method shown in FIG. 4 or FIG. 8. That is, in the welding method using the welding apparatus shown in FIG. 13, the guide portion 31 is arranged so as to be in contact with the workpiece 5 during welding. Therefore, the position of the non-consumable electrode 4 of the welding torch 2 is controlled by displacing the linear guide 30 in accordance with the displacement of the workpiece 5 . Specifically, in the normal line 5c direction (see FIG. 8), the distance H1 from the bent part of the workpiece 5 to the non-consumable electrode 4 (or from the top surface of the extending part of the workpiece 5 to the non-consumable electrode The distance h) to the electrode 4 is adjusted.

In the above welding method, the guide portion 31 and the welding torch 2 are integrally constructed and connected to the linear guide 30. From a different perspective, the guide section 31 and the welding torch 2 are connected to the linear guide 30 in a state where the relative positional relationship between the guide section 31 and the welding torch 2 is fixed. The position of the non-consumable electrode 4 of the welding torch 2 is controlled by the guide part 31 and the linear guide 30. In the method of controlling the position of the non-consumable electrode 4 of the welding torch 2 using the detection unit 9 shown in FIG. There is a concern that a considerable time lag may occur in controlling the position of the electrode 4. Therefore, when the welding speed increases, a problem may occur because the adjustment of the position of the non-consumable electrode 4 relative to the workpiece 5 is delayed in response to the displacement of the workpiece 5 due to the time lag. On the other hand, according to the welding method using the welding apparatus 1 according to the fifth embodiment, the guide section 31 comes into contact with the workpiece 5 and the displacement of the workpiece 5 can be directly detected by the guide section 31. Since the guide portion 31 and the welding torch 2 are integrated and can be moved by the linear guide 30, the position of the non-consumable electrode 4 can be directly adjusted in accordance with the displacement of the workpiece 5. That is, since the non-consumable electrode 4 and the guide portion 31 are mechanically connected, the influence of the welding speed can be suppressed in adjusting the position of the non-consumable electrode 4. As a result, the welding quality in the welding step (S2) can be made more stable.

<Effect>
The welding device 1 according to the present disclosure includes a guide section 31 and a linear guide 30 as an adjustment section. The guide portion 31 contacts the workpiece 5 to be welded. A linear guide 30 serving as an adjustment section is connected to a guide section 31 and a non-consumable electrode 4. The linear guide 30 as an adjustment section adjusts the position of the non-consumable electrode 4 according to the displacement of the workpiece 5 detected via the guide section 31. In this case, welding quality can be stabilized.

Embodiment 6.
<Configuration of welding equipment>
As shown in FIG. 14, the welding device 1 according to the sixth embodiment basically has the same configuration as the welding device 1 shown in FIG. 13, and can obtain similar effects, but the drive unit 8 is different from the welding apparatus 1 shown in FIG. 13 in that it further includes a moving stage 34. The moving stage 34 is connected between the linear guide 30 and the welding torch 2. Specifically, the moving stage 34 is arranged to connect the plate 33 connected to the linear guide 30 and the plate 35. The moving stage 34 can change the relative position of the plate 35 with respect to the plate 33. A torch holder 32 is fixed to the plate 35. The welding torch 2 is connected to the torch holder 32. The distance between the tip of the guide roller 31a and the tip of the non-consumable electrode 4 of the welding torch 2 is adjusted by the moving stage 34. That is, the distance h between the object to be welded 5 and the non-consumable electrode 4 (or the distance H1 from the bent portions 5aa1, 5ba1 of the object to be welded 5 to the non-consumable electrode 4) can be adjusted by the moving stage 34. From a different perspective, the movable stage 34 can change the relative position between the contact position between the guide portion 31 and the workpiece 5 and the non-consumable electrode 4. In FIG. 14, the moving stage 34 is provided between the linear guide 30 and the welding torch 2, but if the distance h between the workpiece 5 and the non-consumable electrode 4 can be adjusted, the moving stage 34 can be placed between the linear guide 30 and the welding torch 2. It may be placed at any position. For example, the moving stage 34 may be arranged to connect the linear guide 30 and the guide section 31, and the relative position of the guide section 31 with respect to the linear guide 30 may be adjusted by the moving stage 34.

FIG. 15 is a schematic diagram showing the configuration of a modification of the welding device 1 according to the sixth embodiment. As shown in FIG. 15, a modification of the welding device 1 according to the sixth embodiment basically has the same configuration as the welding device 1 shown in FIG. 13, and can obtain similar effects. The welding apparatus 1 differs from the welding apparatus 1 shown in FIG. 13 in that the drive unit 8 further includes an air cylinder 36.

The air cylinder 36 is arranged to connect the linear guide 30 and the guide section 31. Specifically, the air cylinder 36 connects the plate 33 connected to the linear guide 30 and the guide roller 31a of the guide section 31. The air cylinder 36 adjusts the protruding length X of the guide roller 31a from the lower end of the plate 33. That is, the distance h between the workpiece 5 and the non-consumable electrode 4 can be adjusted by the air cylinder 36. From a different perspective, the relative position between the contact position between the guide portion 31 and the workpiece 5 and the non-consumable electrode 4 can be changed by the air cylinder 36. In FIG. 15, the air cylinder 36 is provided between the linear guide 30 and the guide part 31, but if the distance h between the workpiece 5 and the non-consumable electrode 4 can be adjusted, the air cylinder 36 can be moved to another position. It may be placed in For example, an air cylinder 36 may be provided between the linear guide 30 and the welding torch 2, and the relative position of the welding torch 2 with respect to the linear guide 30 may be adjusted by the air cylinder 36.

In the welding apparatus 1 shown in FIGS. 14 and 15, the moving stage 34 and the air cylinder 36 are connected to the control section 7 (see FIG. 1). The control unit 7 controls the moving stage 34 and the air cylinder 36. Therefore, the position of the welding torch 2 relative to the workpiece 5 can be changed by the moving stage 34 and the air cylinder 36 controlled by the control unit 7. As a result, the position of the welding torch 2, ie, the position of the non-consumable electrode 4, can be adjusted.

<Welding method>
The welding method using the welding device 1 shown in FIGS. 14 and 15 basically has the same configuration as the welding method using the welding device 1 shown in FIG. 13, and can obtain the same effects. However, it differs from the welding method shown in FIG. 13 in that in the welding step (S2), the distance h between the workpiece 5 and the non-consumable electrode 4 can be changed during welding. . In the welding method using the welding apparatus 1 shown in FIG. 13, the distance h between the workpiece 5 and the non-consumable electrode 4 adjusted in the step (S1) of preparing the material to be welded is adjusted in the welding step (S1). In S2), it is maintained constant according to the displacement of the workpiece 5 to be welded. In the welding method shown in FIGS. 14 and 15, the control unit 7 controls the moving stage 34 or the air cylinder 36 even in the welding step (S2), so that the workpiece 5 and the non-consumable electrode 4 are connected to each other. Distance h can be adjusted during welding.

In this case, even if the appropriate value of the distance h between the workpiece 5 and the non-consumable electrode 4 changes during welding due to constraints on the workpiece 5, the controller 7 By controlling the cylinder 36, it is possible to adjust the distance h between the workpiece 5 and the non-consumable electrode 4 for each welding location. As a result, the welding quality in the welding step (S2) can be made more stable.

An example in which the appropriate value of the distance h between the workpiece 5 and the non-consumable electrode 4 changes during welding will be described. For example, in the welding of the can body 20 in which the head plate part 22 and the body part 21 are welded together as shown in FIG. , 5ba1 and extending portions 5aa2 and 5ba2. In this welding, the ends formed by the bent portions 5aa1 and 5ba1 and the extension portions 5aa2 and 5ba2 are welded together. At this time, assuming that the entire circumference of the end is welded, the welding start position and end position will be the same. Alternatively, the end position is the position where the weld exceeds the start position and wraps to the specified position. In such a case, the appropriate value of the distance h between the workpiece 5 and the non-consumable electrode 4 changes at each of the welding start position, steady state part, and end position. Here, the steady portion is a position between the welding start position and the welding end position. For example, at the welding start position, the shape of the weld at the start position, that is, the width and height of the weld, changes depending on the distance h. At the welding end position, the bent parts 5aa1, 5ba1 and the extension parts 5aa2, 5ba2 shown in FIGS. 4 and 5 have already been welded at the welding start position, so the shape of the welded part has changed. When welding the can body by welding the end plate part 22 and the body part 21, as described above, the welding part is lapped until the welding start and end positions are the same or the end position exceeds the start position. Therefore, it is undesirable for the shape of the welded part at the welding start position to be extremely different from the shape of the welded part at the welded end position because the shape of the welded part will be non-uniform. Therefore, it is preferable to appropriately adjust the distance h between the workpiece 5 and the non-consumable electrode 4 at each position. Furthermore, the appropriate value for the distance h between the workpiece 5 and the non-consumable electrode 4 may not be uniquely determined because it may change depending on the performance required of the welding part. In such a case, the welding method using the welding apparatus 1 shown in FIGS. 14 and 15 is effective.

For example, the following method can be used to change the distance h between the welding start position, steady portion, and end position. Regarding the angle seen from the center of the can body when performing all-around welding in the welding of the can body described above, the distance is calculated at each of the angle corresponding to the start position, the angle corresponding to the steady part, and the angle corresponding to the end position of the weld. Set h. The distance h may be adjusted by controlling the moving stage 34 or the air cylinder 36 by the control unit 7 when the welding portion reaches a predetermined angle. Another method is to calculate in advance the time required to perform all-around welding, and calculate the time corresponding to the welding start position, the time corresponding to the steady part, and the time corresponding to the end position. Set the distance h with . When a predetermined time has elapsed during welding, the distance h may be adjusted by controlling the moving stage 34 or the air cylinder 36 by the controller 7. Here, the angle and time have been explained as an example as criteria for adjusting the distance h, but the invention is not limited to this, and for example, the distance h may be set based on the length to be welded. In addition, although an example has been shown in which the distance h is set in three parts: the welding start position, steady state part, and end position, the distance h is not limited to this, and the parts where the distance h is set can be increased or decreased depending on the workpiece 5. You can.

The welding apparatus 1 may include the moving stage 34 between the linear guide 30 and the welding torch 2 as described above. Furthermore, an air cylinder 36 may be provided between the linear guide 30 and the guide portion 31. The control unit 7 may control the distance h between the workpiece 5 and the non-consumable electrode 4 by controlling the moving stage 34 and the air cylinder 36. Alternatively, the projecting length X of the guide roller 31a of the guide portion 31 may be configured to be adjustable with a screw. Furthermore, it may include a driver for the screw that can automatically adjust the length X. The control unit 7 may adjust the protruding length X of the guide roller 31a by controlling the drive unit. Further, the welding device 1 may include a plurality of guide rollers 31a, and the protruding length The length X may be adjusted. As a result, by using the welding apparatus 1 described above, welding quality can be stabilized even if the appropriate distance h changes for each welding location of the workpiece 5.

<Effect>
In the welding method according to the present disclosure, in the welding step (S2), the distance H1 from the bent portions 5aa1 and 5ba1 to the non-consumable electrode 4 (that is, the distance h between the workpiece 5 and the non-consumable electrode 4) is , can be changed for each different position of the portion where the first end of the first workpiece 5a and the second end of the second workpiece 5b abut against each other. In this case, welding quality can be stabilized.

The welding device according to the present disclosure includes a moving stage 34 or an air cylinder 36 as a position adjustment mechanism. The position adjustment mechanism (moving stage 34 or air cylinder 36) can change the relative position between the contact position between the guide portion 31 and the workpiece 5 and the non-consumable electrode 4. The control unit 7 changes the relative position between the contact position and the non-consumable electrode 4 by controlling a position adjustment mechanism (moving stage 34 or air cylinder 36). In this case, even if the optimal distance H1 (or distance h) differs for each part to be welded, welding quality can be stabilized.

Embodiment 7.
<Welding method>
The welding method according to the seventh embodiment basically has the same configuration as the welding method shown in FIGS. 2 and 3, and can obtain the same effects, but in the welding step (S2). The operation of the control unit 7 is different. That is, in the welding method according to the seventh embodiment, in the welding step (S2), the control unit 7 (see FIG. 1) controls the workpiece 5 (see FIG. 2) while the arc A (see FIG. 2) is generated. The drive unit 8 (see FIG. 1) is controlled according to the welding location of the workpiece (see FIG. 1), and the attitude of the central axis 4a (see FIG. 16) of the non-consumable electrode 4 (see FIG. 16) with respect to the workpiece 5 is controlled. do. Specifically, the control unit 7 controls the drive unit 8 so that the inclination angle θ of the central axis 4a with respect to the normal line 5c is set to 40° or more and 80° while the arc A is generated, as shown in FIG. Adjust within the range below. At this time, the attitude of the central axis 4a of the non-consumable electrode 4 with respect to the workpiece 5 may be controlled so that the tip position of the non-consumable electrode 4 changes, but preferably the tip position of the non-consumable electrode 4 may be controlled. It is preferable to control the attitude of the central axis 4a of the non-consumable electrode 4 so as not to change.

For example, a robot arm, a rotation stage, or the like can be used as the configuration of the drive unit 8 for controlling the posture of the non-consumable electrode 4 as described above. Further, as shown in FIG. 16, the torch holder 32 holding the welding torch 2 may be moved along an arcuate trajectory. Specifically, the torch holder 32 is fitted into a groove of a plate provided with a groove into which the torch holder 32 is fitted. The torch holder 32 is moved along the groove. Any method can be used to move the torch holder 32. For example, a telescoping cylinder may be connected to the torch holder 32, and the torch holder 32 may be moved along the groove by expanding and contracting the telescoping cylinder.

In the welding method described above, in the welding step (S2), while the arc A is being generated, the control section 7 controls the drive section 8 to align the center axis 4a of the non-consumable electrode 4 with respect to the workpiece 5. Control your posture. In this case, for example, when it is necessary to change the attitude of the central axis 4a of the non-consumable electrode 4 with respect to the workpiece 5, that is, the inclination angle θ of the central axis 4a with respect to the normal line 5c, depending on the welding location, It becomes possible to set an appropriate inclination angle θ for each welding location. As a result, the welding quality in the welding step (S2) can be made more stable.

<Effect>
In the welding method according to the present disclosure, in the welding step (S2), the inclination angle θ is set between the first end of the first workpiece 5a and the second workpiece 5b in a range of 40° or more and less than 80°. It can be changed for each different position of the part where the second end of In this case, welding quality can be stabilized.

The following experiments were conducted to verify the effects of the welding equipment and welding method described above.

(Experiment example 1)
<Sample>
The material constituting the sample is SUS436L specified in the JIS standard. The shape of the sample is a plate. The plate thickness, which is the thickness of the sample, was 0.6 mm. Furthermore, the end portion that would become the welded portion was bent into an L shape. The bent portions were butted together to form a welded portion.

<Test method>
The above welded portion was welded using a TIG welding device having the configuration shown in FIG. In addition, in order to define the welding gap (distance between the objects to be welded) at the welding section, a shim plate was placed between the opposing objects to be welded at the welding section. In addition, the inclination angle θ, which is the angle between the normal line at the welding part of the workpiece and the central axis 4a of the tungsten electrode (see FIG. 2), which is the non-consumable electrode 4 of the welding torch 2, is 25°, 45°, Welding was performed at different angles of angles of 50°, 50°, and 60°. Thereafter, the condition of the welded area was visually checked. The welding conditions are shown in Table 1.

<Results>
The test results are shown in Table 2. In addition, in Table 2, in the welding result column, A indicates that the welded part is in good condition after welding, and B indicates that a defect such as the welded part is not formed properly is indicated. .

As shown in Table 2, when the inclination angle is 25°, a good weld can be obtained if the weld gap is 0.1 mm, but a defect will occur in the weld if the weld gap is 0.15 mm. On the other hand, it has been shown that when the inclination angle is 45° and 50°, the condition of the weld is good if the weld gap is 0.2 mm or less. Furthermore, it has been shown that when the inclination angle is 60°, the condition of the weld is good if the weld gap is 0.3 mm or less.

In this way, compared to the case where the inclination angle is 25°, when the inclination angle is 45° or more, the value of the weld gap at which good welding quality can be obtained may be doubled or tripled. Shown.

Note that when the inclination angle was 80°, the arc A (see FIG. 4) became unstable, and defects occurred in the weld regardless of the welding gap. Therefore, it was shown that good welding quality could be obtained if the inclination angle was less than 80°.

(Experiment example 2)
<Test method>
The vertically downward pressure component of the arc pressure was measured by changing the inclination angle (also called the torch angle) of the central axis of the tungsten electrode as a non-consumable electrode and the welding current. In addition, the vertically downward pressure component of the arc pressure was measured by varying the height from the surface of the workpiece to the tip of the tungsten electrode (also called arc length) and the welding current. In order to measure the vertically downward pressure component of the arc pressure, a water-cooled copper mother plate with through holes formed therein was prepared as an object to be welded. A differential pressure gauge was connected to the through hole from the back side of the water-cooled copper mother plate. In such a measurement system, an arc was generated from the surface side of the water-cooled copper mother plate to the portion where the through hole was formed, and the pressure component was measured. Table 3 shows the conditions during the measurement.

<Results>
FIG. 17 shows the relationship between the inclination angle and the vertically downward pressure component of the arc pressure. In FIG. 17, the horizontal axis indicates the inclination angle, and the vertical axis indicates the vertically downward pressure component of the arc pressure. Here, the maximum value during measurement (also referred to as maximum arc pressure) was adopted as the pressure component. Further, FIG. 17 shows relative values when the pressure component is 1 when the inclination angle is 0°, the welding current is 100 A, and the arc length is 3 mm. The welding current was 100 A or 200 A, and the inclination angle was 0°, 25°, and 50°.

As can be seen from FIG. 17, the degree of decrease in maximum arc pressure when the inclination angle is set to 25° is greater than that when the inclination angle is set to 25° compared to the case where the inclination angle is set to 25°. The degree of decrease in maximum arc pressure is relatively large when the angle is set to 50°.

Furthermore, as can be seen from FIG. 17, when the welding current is 100 A, by setting the inclination angle to 40° or more, the maximum arc pressure is halved compared to when the inclination angle is 0°. Furthermore, when the inclination angle is 0°, by increasing the welding current from 100 A to 200 A, the maximum arc pressure is approximately 2.2 times greater. On the other hand, the maximum arc pressure when the welding current is 200 A and the inclination angle is 50° is equal to or lower than the maximum arc pressure when the welding current is 100 A and the inclination angle is 0°. Such a tendency can be confirmed when the inclination angle is 40° or more. In this way, it was shown that the increase in arc pressure due to increase in welding current can be suppressed by increasing the inclination angle.

FIG. 18 shows the relationship between the arc length and the vertically downward pressure component of the arc pressure. In FIG. 18, the horizontal axis represents the arc length, and the vertical axis represents the vertically downward pressure component of the arc pressure. Here, as the pressure component, the maximum value during measurement (also referred to as maximum arc pressure) was adopted as in FIG. 17. Moreover, FIG. 18 shows relative values when the above pressure component is set to 1 when the inclination angle is 0°, the welding current is 100 A, and the arc length is 1 mm. Measurements were conducted under the following conditions: the welding current was 100 A or 200 A, and the arc length was 1 mm, 3 mm, and 5 mm. The inclination angle under each condition was 0°.

As can be seen from FIG. 18, the maximum arc pressure also changes as the arc length changes. The arc pressure can be reduced by increasing the arc length, that is, by increasing the height from the workpiece to the tip of the tungsten electrode.

(Experiment example 3)
<Sample>
A sample similar to that used in Experimental Example 1 was used.

<Test method>
The temperature distribution at the end of welding in the front region of the molten pool was measured by changing the inclination angle (torch angle) of the central axis of the tungsten electrode as a non-consumable electrode. A K-type thermocouple was used as the temperature measuring device. Table 4 shows the conditions during measurement.

<Results>
The results are shown in FIG. In FIG. 19, the horizontal axis indicates the distance from the tip of the melt pool. Further, the vertical axis indicates the temperature at each position of the welded object at the end of welding (that is, when the arc is extinguished). In FIG. 19, results are shown for tilt angles of 25° and 60°.

As can be seen from FIG. 19, the temperature in the front region of the melt pool was higher when the inclination angle was 60° than when the inclination angle was 25°. In other words, it was shown that by increasing the inclination angle, the preheating effect in the front region of the melt pool could be increased.

In addition, in the above-mentioned experimental example, the experiment was conducted using a flat plate as the object to be welded, but when the surface of the object to be welded is curved (the body and the body forming the can in Embodiment 4) Similar results can be obtained even when the end plate is used as the object to be welded.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 welding device, 2 welding torch, 3 nozzle, 4 non-consumable electrode, 4a central axis, 5 object to be welded, 5a first object to be welded, 5aa1, 5ba1 bent part, 5aa2, 5ba2 extension part, 5aa first end Part, 5b second workpiece, 5ba second end, 5c normal line, 6 power supply, 7 control unit, 8 drive unit, 9 detection unit, 9a sensor, 9b voltage sensor, 10 arrow, 20 can body, 20a straight line , 20b Line segment, 21 Body part, 21a End part, 21b Rotation center axis, 21c Vertex, 22 End plate part, 22a Outer circumference part, 25 Jig, 30 Linear guide, 30a Linear guide rail, 30b Linear guide block, 31 Guide part , 31a guide roller, 31b bracket, 32 torch holder, 33, 35 plate, 34 moving stage, 36 air cylinder, A arc, H1, H2, h distance, L length, M weld metal, P molten pool.

Claims

preparing a first workpiece having a first end and a second workpiece having a second end;
a non-consumable electrode having a central axis in a state where the first workpiece and the second workpiece are arranged so that a portion where the first end and the second end meet is formed; Welding the part using an arc generated by
In the welding step,
welding the portion while moving the non-consumable electrode relative to the portion;
The central axis of the non-consumable electrode is in a direction opposite to the direction of movement of the non-consumable electrode with respect to the portion with respect to the normal to the surface of the first workpiece and the second workpiece at the part. It is sloping towards
The welding method, wherein the inclination angle of the central axis with respect to the normal line is 40° or more and less than 80°.
In the portion, one of the first end portion and the second end portion includes a bent portion bent so as to have an L-shape in a cross section perpendicular to the moving direction, and a portion from the bent portion to the said bent portion. an extension part extending in a direction along the normal line;
The welding method according to claim 1, wherein the other of the first end and the second end is arranged to face the bent part.
The welding method according to claim 2, wherein the distance from the bent portion to the non-consumable electrode in the direction of the normal line is greater than or equal to the distance from the bent portion to the top surface of the extended portion.
The welding method according to claim 3, wherein in the welding step, the distance from the bent portion to the non-consumable electrode is adjusted according to the displacement of the extending portion.
The welding method according to claim 4, wherein in the welding step, the distance from the bent portion to the non-consumable electrode can be changed for each different position of the portion.
The welding method according to any one of claims 1 to 5, wherein in the welding step, the inclination angle can be changed for each different position of the portion in a range of 40° or more and less than 80°. .
A method for manufacturing a can using the welding method according to any one of claims 1 to 6, comprising:
In the step of preparing,
A cylindrical body portion constituting the can body is prepared as the first object to be welded,
preparing a head plate portion of the can body as the second object to be welded;
The first end is an annular end in the extending direction of the body,
The second end portion is an outer peripheral portion of the end plate portion,
In the welding step,
The body portion and the mirror plate portion are arranged such that the portion where the end portion of the body portion and the outer peripheral portion of the mirror plate portion are butted together is formed;
While fixing the non-consumable electrode, welding the body part and the end plate part while rotating the body part and the end plate part about a central axis of rotation extending along the extending direction of the body part,
The method for manufacturing a can body, wherein the normal line is a straight line that is perpendicular to the rotation center axis and connects the rotation center axis and the tip of the non-consumable electrode.
In the welding step,
The body portion and the end plate portion are arranged such that the rotation center axis extends along a horizontal direction,
When viewed from the direction along the rotation center axis, the non-consumable electrode is disposed in a region on the front side in the rotation direction of the body part and the mirror plate part from the uppermost vertex of the body part. The method for manufacturing a can body according to claim 7.
a non-consumable electrode having a central axis;
a power source for powering the non-consumable electrode;
A welding apparatus, comprising: a control section that controls a posture of the central axis of the non-consumable electrode with respect to a workpiece.
comprising a detection unit that detects displacement of the welded object,
The welding apparatus according to claim 9, wherein the control section controls the position of the non-consumable electrode according to the displacement of the workpiece detected by the detection section.
a guide portion that is brought into contact with the object to be welded;
an adjustment section connected to the guide section and the non-consumable electrode;
The welding apparatus according to claim 9, wherein the adjustment section adjusts the position of the non-consumable electrode according to the displacement of the workpiece detected via the guide section.
comprising a position adjustment mechanism capable of changing a relative position between a contact position between the guide part and the workpiece and the non-consumable electrode;
The welding apparatus according to claim 11, wherein the control unit changes the relative position between the contact position and the non-consumable electrode by controlling the position adjustment mechanism.