JP3585609B2 - Arc welding method and welding products for aluminum members - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for welding an aluminum member with improved shape accuracy after welding and a welded product such as a viscous damper.
[0002]
[Prior art]
As a method of welding and sealing a lid to an aluminum container body, Japanese Patent Application Laid-Open No. 63-264282 discloses that welding is performed using a high energy density beam such as an electron welding beam. By utilizing this, when manufacturing a viscous damper used as a member for preventing vibration of a vehicle, an iron ring is housed in a casing, and then the lid is welded and sealed by high energy beam welding in a final welding process. .
As shown in FIG. 1, the viscous damper has an annular container 2 having a rectangular cross section on the periphery of a circular flat plate 1. For the circular flat plate portion 1 and the annular container portion 2, one integrally formed of an aluminum material is used. If an aluminum viscous damper is used instead of iron, the tertiary resonance in the overrun region is greatly reduced, vibration due to torsional resonance in normal rotation is reduced, and the temperature rise of silicone oil is suppressed, preventing oil deterioration. Yes (see the Society of Automotive Engineers of Japan Academic Lecture Preprint 943, pages 45-48).
[0003]
An opening 3 through which the shaft of the crankshaft is inserted is formed in the center of the circular flat plate 1. The annular container portion 2 accommodates an iron ring 4 in an internal cavity, and a gap between the iron ring 4 and the annular container portion 2 is filled with silicone oil or the like. Further, a buffer material 5 such as a fluororesin is interposed so that the iron ring 4 does not directly collide with the inner wall of the annular container portion 2.
According to the conventional method of manufacturing an aluminum viscous damper, the annular container 2 is sealed with the iron ring 4 housed therein before filling with silicone oil or the like. That is, as shown in FIG. 2A, after the iron ring 4 is put in the container body 6, the lid 7 is attached. The lid 7 is attached to the container body 6 by crimping the upper wall 8 of the container body 6 toward the lid 7. At this time, in order to ensure the sealing property of the silicone oil or the like in the sealing portion, as shown in FIG. Is sandwiched.
[0004]
[Problems to be solved by the invention]
In the joining by caulking, the joining strength between the container main body 6 and the lid 7 is weak, and the joint between the container main body 6 and the lid 7 is attached to a crankshaft to which centrifugal force, vibration and impact due to high-speed rotation are repeatedly applied. The gap which causes the oil leak is likely to be generated. Moreover, in order to facilitate the crimping work, it is necessary to form the thinned upper wall 8 and the brim portion 9 as shown in FIG. 2B, which leads to an increase in man-hours and work time.
Therefore, welding and the like have recently been studied as an alternative to caulking. For example, Japanese Patent Application Laid-Open No. 63-264282 cited above introduces a method of sealing a container by welding with high energy beams such as an electron beam and a laser beam. However, since these welding methods require special equipment, initial costs, running costs, and the like increase.
[0005]
When an attempt is made to seal the container by a typical MIG welding method, which is a typical welding method, the heat input amount per unit length is large, and the thermal deformation of the container base material is large. Further, since the temperature becomes high, it is impossible to insert a component such as a fluororesin or a rubber therein. The large thermal deformation also causes the desired vibration absorption characteristics to be impaired when the device is mounted on a crankshaft. Further, since the bead width and the margin are large and the sagging of the edge portion is likely to be large, the appearance of the product is deteriorated.
Such a problem is caused not only by the aluminum viscous damper shown in FIGS. 1 and 2 but also by an accumulator, a water pump, and a torque converter as long as an aluminum inner material is welded to an aluminum outer material to form a container. This also occurs in cases, hermetic terminals, liquid and gas tanks, and the like.
[0006]
With an aluminum member having good thermal conductivity, it is difficult to weld even a member having a large difference in heat capacity. That is, in a member having a large heat capacity, the input heat amount is diffused into the member by the heat transfer, and it is difficult for the welding location to rise to a required welding temperature. On the other hand, in a member having a small heat capacity, the temperature rapidly rises due to the heat input during welding, and the temperature easily rises until local deformation occurs. For this reason, welding defects such as burn-through and poor weld bead shape are likely to occur, and it is necessary to control welding conditions with high precision. In addition, when the joint portion shown in FIG. 2 is to be joined by welding, the arc wraps around the outer surface of the upper wall 8 at the time of welding, which may cause sagging at the edge and various defects on the surface. There is.
The present invention has been devised to solve such a problem. By arranging a jig having a function of covering a material to be welded in the vicinity of a welded part and adjusting a heat capacity, sagging and burn-through are prevented. An object of the present invention is to prevent welding and weld aluminum members having significantly different heat capacities without causing deterioration of the material due to excessive heat input. It is another object of the present invention to perform welding well even in a case where the width of a welding surface of a material to be welded is small with respect to the spread of an arc, and an undesired portion is melted by the arc.
[0007]
[Means for Solving the Problems]
Arc welding method of the present invention in order to achieve the purpose, if the spread width W _a is smaller than on the surface of the material to be welded in arc width W _b of the workpieces is radiated from the electrode of the welding torch, a large heat capacity Arc welding is performed by bringing the jig into contact with the surface of the material to be welded that is not to be melted.
Assuming that the width of the jig is W _j , the width of the material to be welded is W _b , and the width of spread of the arc on the surface of the material to be welded is W _a , W _j > W _a −W _b Is preferably used. As the jig, a jig having a built-in water cooling or air cooling mechanism can be used.
According to the present invention, an aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is placed in the cylindrical aluminum casing. Can be welded and sealed so as to form the same plane. In this case, a jig having an upper end surface at the same height as or higher than the casing main body and the cover, a jig for partially covering the upper end surface of the casing, or the like is used.
[0008]
The jig has upper surface above the casing, when the plate thickness of the upper part of the step portion of the cylindrical aluminum casing body t, the jig height projecting from the casing upper surface and t _1, jig is used with a jig height t ₁ of t ₁ ≦ 100 / t. As the jig for covering the upper end face part of the casing, when the protrusion width of the jig covers the casing upper surface and t _2, using a jig with t ₂ <protrusion width t ₂ to t . Furthermore, when the distance from the upper end surface of the casing to the jig surface covering the casing surface is t ₃ , a jig having a distance t ₃ of t ₃ ≦ t ₂ is used.
If you want to put a corner radius R at the corners, when welding the cover to the casing body, using a jig with only low jig height height difference t ₄ when required for corner radius R of the casing. When welding a disk-shaped cover to a cylindrical aluminum casing, a jig that moves along the outer peripheral surface of the casing may be used. The welding speed is set in the range of 1 to 7 m / min, preferably 2 to 5 m / min so as not to give an excessive amount of heat to the material to be welded.
[0009]
[Action]
When welding aluminum members having significantly different heat capacities, the heat conduction of the aluminum members is large and the melting point is relatively low, so that damage due to heat input during welding is greater than that of iron-based members. For example, as shown in FIG. 3, when the vertical aggregate 12 is arc-welded to the panel 11, the T-shaped joint in which the height of the vertical aggregate 12 is lower than the spread width of the arc tends to cause sagging due to the wraparound of the arc 13. , And a healthy rib shape cannot be maintained. Further, in the T-shaped joint in which the height of the vertical aggregate 12 is low, the heat balance between the panel 11 and the vertical aggregate 12 is poor, and the temperature of the vertical aggregate 12 is excessively increased as compared with the panel 11, so that the vertical bone The material of the material 12 softens, and the material strength decreases.
In the present invention, a jig 14 as shown in FIG. 4 is used in order to prevent such arc wraparound and excessive temperature rise. The jig 14 is preferably made of a material having a high heat conductivity and easy to conduct heat with the material to be welded made of aluminum and having a large heat capacity. For example, a material having a larger sectional area than the material to be welded and made of a material such as an aluminum material or a copper material which is formed in a close contact shape is used.
[0010]
The jig 14 shown in FIG. 4A includes a pressing portion 15 that comes into contact with the upper end surface of the vertical aggregate 12, and an inclined surface 17 inclined from the pressing portion 15 to the lower surface along the welding bead 16. Pressing portion 15, the spread width _{W a} of the arc 13, when the width of the vertical aggregate 12 and _{W b,} are set to W _j> W a -W _b satisfies the jig width _{W j.} Thereby, the arc 13 is prevented from wrapping around the surface of the vertical aggregate 12 other than the portion to be welded, and the surface after welding is maintained in a sound state without welding marks or the like. Moreover, _case, the jig 14 is used with a W _j> W a -W _b satisfies the jig width _{W j} shed arc 13 against the workpieces 18, as shown in a right angle Fig 4 (b) Is done. In this specification, the spread width W _a of the arc shows the spread width on the surface of the street workpieces shown in FIG.
These dimensions are the same even when the axis of the torch is displaced from the welding center as shown in FIG. 4C, and when the axis of the torch is inclined. Further, as shown in FIG. 4D, the same applies to the case where three materials are overlap-welded simultaneously. As described above, the outer edge of the arc covers the portion of the material to be welded that is not to be melted with the jig having a large heat capacity.
As described above, when arc welding by applying a jig 14 having such a jig width W _j in the vertical aggregate 12, since the amount of heat applied to a small vertical aggregate 12 of the heat capacity is transmitted to the jig 14 In addition, the vertical aggregate 12 is prevented from being excessively heated. As a result, sag that tends to occur particularly at the corners of the vertical aggregate 12 is eliminated. In addition, since excessive temperature rise is suppressed, distortion and deformation are suppressed, and the shape accuracy of the welded product is improved.
[0011]
In a viscous damper or the like in which a disk-shaped lid is welded and sealed to a cylindrical casing, the jig 14 is applied to the outside of the casing 19 as shown in FIG. Then, the cover 21 is fitted to the step portion 20 formed on the upper edge of the casing 19, and the cover 21 is arc-welded to the casing 19. By applying the jig 14, a healthy surface state is maintained without the arc 13 wrapping around the outer peripheral surface of the casing 19. Also, the shape of the formed weld bead 22 is stabilized. On the other hand, if the cover 21 is welded and sealed without using the jig 14, the weld bead 22 will sag due to the wraparound of the arc 13 as shown in FIG. Further, the corners of the casing 19 are burnt off, and the shape after welding is deteriorated.
In the design in which the cover 21 is sealed to the casing 19 by welding, a step portion 20 is usually formed at the upper end edge of the casing 19, and the cover portion is formed on the joint portion 23 whose thickness is reduced to t as shown in FIG. The cover 21 is welded to the casing 19 after fitting the edges of the 21 and forming the groove 24 as necessary. In this case, as shown in FIG. 6B, the use of the jig 14 having a height protruding from the upper end surface of the casing 19 reliably prevents the arc from turning around.
[0012]
The height t ₁ of the jig 14 protrudes from the upper end surface of the casing 19, it is preferable that the relative to the thickness t of the joint portion 23 satisfy the relation of t ₁ ≦ 100 / t. The height t ₁ can be prevented even wraparound arc beyond the 100 / t, due to defects are likely to occur for example t _1> 20 mm next time t = 5 mm, the shield shortage due to the welding torch is increased .
As the jig 14, as shown in FIG. 6C, a jig having a water cooling mechanism for circulating cooling water or an air cooling mechanism may be used. The jig 14 with a built-in cooling mechanism promotes heat dissipation from the thinned joint portion 23 and prevents the joint portion 23 from excessively rising in temperature.
[0013]
As shown in FIG. 6D, the jig 14 may be formed with a protruding portion 25 for pressing a part of the upper end surface of the casing 19 to reduce the melting width of the upper surface of the joint portion. The length t ₂ which covers the upper end surface of the protruding portion 25 the casing 19, it is necessary to be smaller than the thickness t of the joint portion 23 for securing the welds. In this case, as shown in FIG. 6E, a gap 26 can be provided between the upper end surface of the casing 19 and the protruding portion 25. In this case, it is effective that the distance t _{3 of the} gap 26 be equal to or less than the length t ₂ of the protrusion 25 covering the upper end surface of the casing 19. When the distance t ₃ is greater than the length t _2, together with the effect of reducing the melt width of the upper end surface of the casing 19 is reduced by the welding arc, fear arises that the projecting portion 25 is melted.
If you want with a corner radius R is in the corners, as shown in FIG. 6 (f), it is preferable to use a jig 14 which is lower by height difference t ₄ as compared to the upper end surface of the casing 19. This intends to form a corner radius R by intentionally utilizing the wraparound of the arc. For example, when the height difference t ₄ and 2 mm, the surface tension and interfacial tension of the molten metal upper outer peripheral portion of the casing 19 by diffraction of the arc can generally form a corner radius R of 2 mm.
[0014]
The present invention can be applied to a case where a flange 28 is welded to a cylindrical pipe material 27 as shown in FIG. The flange 28 is smaller than the tube 27. Therefore, when welding is performed by a normal welding method, the temperature of the flange 28 having a small heat capacity excessively rises, and the sag 29 is easily generated on the flange 28 as shown in FIG. 7B. In an extreme case, the weld bead 22 rises to the side surface of the flange 28, and the required shape accuracy cannot be secured.
Therefore, as shown in FIG. 7C, a jig 14 that accommodates the pipe material 27 and has an inner peripheral surface that contacts the side surface of the flange 28 is used. When welding is performed in a state where the side surface of the flange 28 is covered by the jig 14, heat concentrated on the flange 28 at the time of welding is dissipated to the jig 14, so that the flange 28 is not excessively heated, and distortion due to welding heat input is prevented. And deformation are prevented. In addition, since the side surface of the flange 28 is covered with the jig 14, the wraparound of the arc is prevented, and the flange 28 is maintained in a sound surface state even after welding.
[0015]
When the aggregate is welded to the panel, it is preferable to press a rollable roller-like jig 30 against the end face of the aggregate 31 as shown in FIG. As shown in FIG. 8A, the roller-shaped jig 30 is pivotally supported by a sagging prevention frame 32 that sandwiches the aggregate 31, and is pressed against the end face of the aggregate 31 by a pressing force F. A plurality of roller-shaped jigs 30 can be arranged in the welding direction as shown in FIG. In this case, each roller-shaped jig 30 is pressed equally to the aggregate 31 by applying a pressing force F through a frame 33 to a sagging prevention frame 32 that supports a plurality of roller-shaped jigs 30. Can be When the welding torch 34 is attached to the frame 33, the roller-shaped jigs 30, 30,... Move in synchronization with the welding torch 34.
Therefore, the aggregate 31 is fillet-welded to the panel 35 while the required portion of the aggregate 31 is pressed against the panel 35 by the roller-shaped jigs 30, 30,. The welding beat 22 is formed in a favorable shape at the corners of the panel 35 and the aggregate 31. Further, since the jigs 30 are protected by the roller-shaped jigs 30 and the sagging prevention frame 32, the arc 13 does not go around the end face of the aggregate 31. Therefore, the finish after welding is also excellent.
[0016]
When the cover is welded and sealed to the cylindrical casing, a jig that rolls along the outer peripheral surface of the casing can be used as shown in FIGS.
The jig 36 in FIG. 9 has a flange 38 integrally formed at the end of a cylindrical body 37, and rotates around a rotation shaft 39. The cylindrical body 37 is in contact with the outer peripheral surface of the casing 19, and the brim portion 38 covers the upper end surface of the casing 19. When the cylindrical body 37 is pressed against the outer peripheral surface of the casing 19 with the pressing force F and the casing 19 or the jig 36 is relatively rotated as shown in FIG. Move on the outer peripheral surface.
The jig 40 of FIG. 10 includes a jig main body 41 having an inner surface curved along the outer peripheral surface of the casing 19, and a plurality of rollers 42 are rotatably provided on the inner surface of the jig main body 41. When the casing 19 or the jig 40 is relatively rotated as shown in FIG. 10B, the jig 40 also moves on the outer peripheral surface of the casing 19 while rotating.
[0017]
【Example】
An embodiment in which the present invention is applied to welding and sealing a cover to a container body (casing) of a viscous damper will be described. As the container body 6, an aluminum alloy JIS A6061 forged material having an annular cavity having an outer diameter of 272 mm, an inner diameter of 264 mm, and a depth of 24 mm at the upper end of the outer peripheral wall was used. As the lid 7 to be welded and sealed in the annular cavity, an annular disk having an outer diameter of 264 mm, an inner diameter of 177 mm, and a thickness of 4 mm made of the same aluminum alloy JIS A6061 was used.
As shown in FIG. 11A, when the lid 7 is welded and sealed to the container main body 6 in which the iron ring 4 is accommodated in the annular cavity, the container main body 6 is placed on the lower surface jig 43 and directed toward the center. And press the side jig 44. The lower surface jig 43 has a depression formed on the surface thereof roughly corresponding to the bottom surface shape of the container body 6, and stably supports the placed container body 6. The side jig 44 is divided into an appropriate number in the circumferential direction. In the example of FIG. 11, a structure is employed in which the three-parted side jig 44 is pressed against the outer peripheral surface of the container body 6.
[0018]
After the bottom and side surfaces of the container body 6 are supported by the lower surface jig 43 and the side surface jig 44, respectively, the lid 7 is placed on the upper surface opening portion. The lid 7 is formed into an annular disk that fits into the annular cavity of the container body 6, and is pressed against the container body 6 by the force applied to the cover holding jig 45. The cover holding jig 45 is an annular disk having a width slightly smaller than the width of the lid 7. Therefore, when the cover holding jig 45 is disposed on the lid 7, the welded sealing portions 46 and 47 between the container body 6 and the lid 7 are exposed on the inner peripheral side and the outer peripheral side of the cover holding jig 45.
As shown in FIG. 12, the container body 6 and the lid 7, whose positional relationship is fixed by the jigs 43 to 45, are tightened by the clamp 48 and supported by the chuck 49. Then, the welding sealing portions 46 and 47 are welded while rotating the container body 6 and the lid 7 by the motor 50. FIG. 11B shows a state in which the lid 7 is welded and sealed to the container body 6 in this manner.
[0019]
A groove having a groove angle of 45 to 70 degrees and a groove depth of 1.5 to 2 mm was formed on the welded sealing portions 46 and 47. While supplying argon as a shielding gas at a flow rate of 25 l / min, a filler material of 5356 WY having a diameter of 1.2 mm is used, a current of 170 to 230 A, a voltage of 19.5 to 25 V, a torch advance angle of 10 degrees and a target angle of 0 degrees. Under the following conditions.
The container body 6 with the lid 7 welded and sealed was taken out of the jigs 43 to 45, and the deformation was measured at six measurement points P at equal intervals along the circumferential direction as shown in FIG. . When the measurement results of the deformation amount were arranged by the presence or absence of the jig and the welding speed, as shown in FIG. 14, compared with the case where welding was performed without using the jigs 43 to 45, In the case where the main body 6 and the lid 7 were welded while being restrained, the amount of deformation was significantly reduced. Even when the container body 6 and the lid 7 were restrained by the jigs 43 to 45, the deformation amount decreased as the welding speed was increased.
[0020]
From this, it is understood that heat is absorbed by the jigs 43 to 45 at the time of welding, and heat balance is achieved even when welding the container body 6 and the lid 7 having different heat capacities. As a result, thermal deformation of the container body 6 and the lid 7 was suppressed, and sagging of the container body 6 was also prevented. In addition, even at a welding speed of 2 m / min or less, sagging hardly occurred and the non-melting width was large, as shown in FIG. 15 by comparing the absence of the jig (a) with the presence of the jig (b). Therefore, the conditions were relaxed even in the aim which had been a problem in high-speed MIG welding at a welding speed of 5 m / min or more, and welding was facilitated. Furthermore, even if there is a gap of 0.3 mm between the welding portion of the container body 6 and the lid 7, the deformation amount is small, so that the processing cost of the material to be welded can be reduced.
[0021]
【The invention's effect】
As described above, in the present invention, when welding aluminum members having significantly different heat capacities, a jig that covers the material to be welded in the vicinity of the welded portion and has a function of adjusting the heat capacity is arranged to prevent dripping and burn-through. This prevents deformation and material deterioration due to excessive heat input. In addition, since the arc is prevented from being wrapped around by the jig, the surface of the welded aluminum member is also maintained at a sound surface free from defects such as welding marks. Moreover, since excessive temperature rise is suppressed, distortion and deformation are suppressed, and the shape accuracy of the welded product is improved. Thus, according to the present invention, a welded product having good shape characteristics and surface condition can be obtained even with aluminum members having greatly different heat capacities.
[Brief description of the drawings]
FIG. 1 is a perspective view of a viscous damper containing an iron ring with a part cut away. FIG. 2 is a cross-sectional view in which a lid is attached to a container body of the viscous damper by caulking, and an enlarged cross-sectional view of a sealing portion. (B)
FIG. 3 is an explanatory view of welding a vertical aggregate to a panel; FIG. 4 is an explanatory view of welding a vertical aggregate to a panel by disposing a jig according to the present invention; FIG. Explanatory diagram for welding (b), explanatory diagram for welding the lid to the container (c), and explanatory diagram for welding three plates (d)
FIGS. 5A and 5B are an explanatory view in which a jig is arranged on the outer periphery of a casing of a viscous damper and a cover is welded, and an explanatory view in which welding is performed without using a jig;
FIG. 6 shows several examples of jigs according to the present invention. The jig has the same height as the casing (a), the jig is higher than the casing (b), the jig with a built-in water cooling mechanism (c), A jig (d) for covering the casing, a jig (e) having a projection formed with a gap between the casing and the surface of the casing, and a jig (f) having an upper end surface lower than the surface of the casing are used. FIG. 7 shows a state in which a flange is welded to a pipe material in accordance with a target shape (a) after welding, a shape after welding (b) in which sagging occurs, and the present invention. (C) after welding formed by using a jig
FIGS. 8A and 8B are a cross-sectional view and a side view illustrating a state where welding is performed while restraining the aggregate using a roller-shaped jig.
FIG. 9 is a side sectional view (a) and a plan view (b) when the cover is welded and sealed while pressing the side surface of the casing with a roller-shaped jig.
FIG. 10 is a side sectional view (a) and a plan view (b) when the cover is welded and sealed while pressing the side surface of the casing with a jig provided with a roller.
11A and 11B are a perspective view and a cross-sectional view of a jig for restraining a container body and a lid welded in the embodiment of the present invention.
FIG. 12 is an explanatory view of a mechanism for rotating a container body and a lid constrained by a jig. FIG. 13 is a side view (a) and a plan view (b) showing measurement points for examining deformation after welding.
FIG. 14 is a graph showing the effect of the jig on the amount of deformation of the welded viscous damper and the welding speed. FIG. 15 is a graph showing the effect of the jig on the length of the sag and the unmelted width and the welding speed. [Explanation of symbols]
1: circular plate portion 2: annular container portion 3: opening portion 4: iron ring 5: cushioning material 6: container body 7: lid 8: upper wall 9: brim portion 10: sealing agent 11: panel 12: vertical aggregate 13 : Arc 14: jig 15: holding part 16: welding bead 17: inclined surface 18: material to be welded 19: casing 20: stepped part 21: cover 22: welded bead 23: joint part 24: groove 25: protruding part 26 : Gap 27: Pipe material 28: Flange 29: Sag 30 Roller jig 31: Aggregate 32: Sag prevention frame 33: Frame 34: Welding torch 35: Panel 36: Jig 37: Cylindrical body 38: Collar 39: Rotation Shaft 40: Jig 41: Jig main body 42: Roller 43: Lower surface jig 44: Side jig 45: Cover holding jig 46: Inner peripheral side welding sealing part 47: Outer peripheral side welding sealing part 48: Clamp 49 : Chuck 50 Motor

Claims (12)

If the surface is smaller than the spread width W _a for the material to be welded in arc width W _b of the workpieces is radiated from the electrode of the welding torch, is brought into contact with a large jig of heat capacity on the surface do not want to melt the workpieces Arc welding method for an aluminum member, characterized by performing arc welding. When the width of the jig is W _j , the width of the material to be welded is W _b , and the spread width of the arc on the surface of the material to be welded is Wa, _a jig having a width of W _j > W _a −W _b is used. An arc welding method for an aluminum member according to claim 1 . 3. The arc welding method for an aluminum member according to claim 1, wherein the jig includes a water cooling or air cooling mechanism . An aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is flush with the cylindrical aluminum casing. When welding and sealing to form, a jig having an upper end surface at the same height as or above the height of the casing main body and the cover as a jig is brought into contact with a side surface of the casing main body. The method for arc welding of an aluminum member according to any one of the above . An aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is flush with the cylindrical aluminum casing. At the time of welding and sealing to form, when the plate thickness of the portion above the step of the cylindrical aluminum casing main body is t, and the jig height projecting from the upper end surface of the casing is t ₁ , t ₁ ≦ arc welding method of an aluminum member according to claim 4 which is brought into contact with the jig having a jig height t ₁ of 100 / t to the side surface of the casing body. An aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is flush with the cylindrical aluminum casing. At the time of welding and sealing so as to form, when the plate thickness above the step of the cylindrical aluminum casing main body is t and the projecting portion width of the jig covering the upper end surface of the casing is t ₂ , t ₂ <t. arc welding method of an aluminum member according to claim 4 or 5 is brought into contact with the jig having a projecting portion width t ₂ of the side surface of the casing body. An aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is flush with the cylindrical aluminum casing. When welding and sealing to form, when the protrusion width of the jig covering the upper end surface of the casing is t ₂ , and the distance from the upper end surface of the casing to the jig surface covering the casing surface is t ₃ , arc welding method of an aluminum member according to claim 6 which is brought into contact with the jig having a distance t ₃ of t ₃ ≦ t ₂ on the side surface of the casing body. An aluminum cover having the same thickness as the height of the step is placed on the step of the cylindrical aluminum casing body having a step at the upper end of the inner wall, and the aluminum cover is flush with the cylindrical aluminum casing. The jig having a jig height that is t ₄ lower than the upper end surface of the aluminum casing when welding and sealing to form the aluminum casing is brought into contact with the side surface of the casing body. 3. The arc welding method for an aluminum member according to claim 1. Using a roller-shaped jig as a jig, pressing the roller-shaped jig against a side surface of a cylindrical aluminum casing main body, and performing arc welding while rolling along the outer peripheral surface of the casing main body in synchronization with a welding torch. An arc welding method for an aluminum member according to any one of claims 4 to 8 . The arc welding method for an aluminum member according to any one of claims 1 to 9, wherein the arc welding is performed at a welding speed of 1 to 7 m / min . An aluminum welded product arc-welded by the method according to claim 1 . An aluminum viscous damper arc-welded by the method according to claim 1.

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