JPH0871755A - Butt one side welding method of aluminum alloy member - Google Patents

Abstract

PURPOSE: To achieve the MIG welding in one pass with hardly generating weld defects such as the incomplete penetration or the like at a groove of a weld joint by composing a butt one side weld joint of a single drawn structure of an aluminum alloy plate to be welded on which a bent part as the single drawn part is formed and another aluminum alloy plate to be welded. CONSTITUTION: A groove having an inclined groove surface 12a where one plate 11 to be welded is inclined toward a bent part 11a, the angle θ to the plate surface (horizontal plane) is 30-60 deg., and the depth (d) from the plate surface is >=1/2 of the thickness (t) of a plate 2 to be welded is formed as the groove of the plate 12 to be welded having no bent part 11a in place of the conventional square groove (vertical groove surface). The groove root part (groove bottom part) can be sufficiently melted by the arc, and the MIG welding can be achieved in one pass with hardly generating weld defects such as incomplete penetration and burn through at the groove part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention constitutes a butt one-side welded joint having a grooved portion with two welded plates made of an aluminum alloy, and the grooved portion of the butted one-side welded joint is formed by one pass. The present invention relates to a butt piece welding method for aluminum alloy members, in which MIG welding is performed.

[0002]

2. Description of the Related Art Conventionally, when welding thin aluminum alloy members having a plate thickness of 5 mm or less, a welded one-sided welded joint having a single-drawing or a double-drawing structure is constructed by these two plates to be welded, and the butting is performed. One groove on the welded joint
Butt one-sided welding is performed so that MIG welding is performed in a pass. For example, in the production of a thin aluminum alloy pressure vessel such as a household LP gas cylinder, in manufacturing the pressure vessel, a single throttle structure having a groove portion for attaching a hemispherical end plate to a cylindrical body plate is provided. The butting one-side welded joint is formed, and the groove portion of the butting one-side welded joint is welded by the one-pass mig welding. In the present specification, "aluminum alloy" means so-called industrial pure aluminum (JIS / A).
(1000 series) is also used in the meaning including.

FIG. 6 is a view showing a joint shape (groove portion shape) of a conventional butt-side welded joint having a single-drawing structure, and FIG. 7 is a joint shape of a conventional butt-side weld joint having another single-drawing structure (groove). It is a figure which shows a part shape.

In the conventional one-side butt welding method, as shown in FIG. 6 or 7, one end of one welded plate 21 of two welded plates 21, 22 having a plate thickness of 5 mm or less and made of an aluminum alloy is used. After being bent diagonally inward, the other welded plate 22 is bent along the back surface of the other welded plate 22, and the other welded plate 22 has an I-shaped groove surface (vertical groove surface) 22a which is left as it is. The bent portion 21a of one welded plate 21 is arranged by overlapping the one welded plate 21 so as to face the obliquely bent bent portion 21a of the welded plate 21.
a and the I-shaped groove surface 22a of the other plate to be welded 22 to form a butt portion 23 having a groove portion 23. The butt one-side welded joint is formed, and the groove portion 23 of the welded joint faces downward. MIG welding is done in one pass in one posture. In addition, in FIG. 7, the to-be-welded plate 21 having the refraction portion 21a is bent further inward at the tip thereof. Further, the two welded plates 21, 22 have the same plate thickness.

[0005]

However, in the above-mentioned conventional butt piece side welding method for aluminum alloy members,
The welded plate has a thermal conductivity about 4 times that of steel and a specific heat of about 1
Since it is / 2, it is made of an aluminum alloy with a narrow melting area by welding, and since its plate thickness is as thin as 5 mm or less, there is concern about burn through and the welding current cannot be increased sufficiently,
As shown in FIG. 8, insufficient penetration (insufficient fusion) often occurs in the groove root portion (groove bottom portion), which causes strength reduction,
The strength of the welded part was sometimes reduced. If only for the purpose of improving the strength, the cost will increase, but it is also possible to deal with it by increasing the plate thickness or by using both abutting joints. However, when X-ray inspection of welded parts is required such as in a pressure vessel, even a welding defect with no problem in strength will be rejected. Eliminating as much as possible has become important.

In view of the above, the present invention constitutes a butt one-sided welded joint having a grooved portion with two welded plates made of an aluminum alloy, and welds the grooved portion of the welded joint into the welded portion due to insufficient penetration or the like. An object of the present invention is to provide a butt-side welding method for aluminum alloy members, which enables MIG welding in one pass with almost no defects.

[0007]

In order to achieve the above-mentioned object, a method for butt-side welding of aluminum alloy members according to the present invention is such that one end of one welded plate of two welded plates made of aluminum alloy is welded. Bent inwardly and then along the back surface of the other plate to be welded, so that the groove surface of the other plate to be welded is opposite to the bent portion of the one plate to be welded. Arranged to configure a butting one-side welded joint of a single-drawing structure in which a groove is formed between the refraction portion of the one plate to be welded and the groove surface of the other plate to be welded,
In a butt piece welding method for an aluminum alloy member in which the groove portion of this welded joint is MIG welded in one pass, the groove surface of the other welded plate is directed toward the bent portion of the one welded plate. And the angle with the plate surface is 3
A groove surface having an inclined groove surface having a depth from the surface of the plate of 0 to 60 degrees and a half or more of the plate thickness of the other plate to be welded is formed, and the groove surface is formed. The groove portion formed between the bent portion and the bent portion of the one plate to be welded is MIG welded in one pass.

[0008]

FIG. 5 is a view showing a joint shape (groove shape) of a butt one-side welded joint having a one-sided drawing structure according to the butt one-side welding method of the present invention. According to the butting one-side welding method for aluminum alloy members according to the present invention, as shown in FIG.
A groove portion is formed by one welded plate 11 made of an aluminum alloy and the other welded plate 12 made of an aluminum alloy in which a bent portion 11a is formed by bending an end portion inwardly to form a one-sided drawing structure. When constructing a butting one-side welded joint having a one-sided drawing structure having the
Instead of the conventional I-shaped grooved surface (vertical grooved surface) as it is, the plate surface (horizontal plane) is inclined toward the bent portion 11a of the one plate 11 to be welded. A groove surface having an inclined groove surface 12a having an angle θ of 30 to 60 degrees and a depth dimension d from the surface of the plate being one half or more of the plate thickness dimension t of the plate 2 to be welded. Is formed, and the groove portion 13 formed between the groove surface having the inclined groove surface 12a and the bending portion 11a is MIG welded in one pass. The plate thickness to which the welding method according to the present invention is applied is 5 mm or less.

As described above, by forming the groove surface having the inclined groove surface 12a as described above on the welded plate 12 which does not have the bending portion 11a for the one-sided drawing structure, the welding current can be obtained. Even if the value is the same as the conventional value, the groove root part (bottom part of the groove part 13) can be sufficiently melted by the arc, and the groove part 13 hardly causes welding defects such as insufficient penetration 1 MIG welding can be performed with a pass.

The angle θ formed by the inclined groove surface 12a and the plate surface is preferably in the range of 60 to 30 degrees. The angle θ is 60
If the vertical angle is exceeded by more than 100 degrees, it is difficult for the arc to reach the groove root part and it is difficult to sufficiently melt the groove root part by the arc, and welding defects due to insufficient penetration easily occur in the groove root part. This is because when the angle becomes smaller than 30 degrees and the inclined groove surface 12a approaches horizontal, burn-through occurs. The angle θ is preferably in the range of 60 to 45 degrees from the viewpoint of preventing a decrease in welding efficiency due to an increase in groove cross-sectional area as compared with the conventional case.

The depth d of the inclined grooved surface 12a from the plate surface is preferably d ≧ (t / 2) where t is the plate thickness of the plate 12 to be welded. d <(t / 2)
In that case, the effect of forming the inclined groove surface 12a is not exhibited, it becomes difficult to sufficiently melt the groove root portion by the arc, and a welding defect due to insufficient penetration easily occurs in the groove root portion. is there.

[0012]

Embodiments of the present invention will be described below.
FIG. 1 is a diagram relating to a welding method according to the present invention, in which a joint shape (opening) of a butt-side welded joint having a single-drawing structure composed of a cylindrical body plate made of an aluminum alloy and a hemispherical end plate made of an aluminum alloy. FIG. 2 is a view showing the structure of a household LP gas cylinder to which the welding method according to the present invention is applied.

As shown in FIG. 2, a household LP gas cylinder made of an aluminum alloy to which the welding method according to the present invention is applied has a three-piece structure including a body portion and upper and lower mirror portions. ), The upper end plate 2 having a hemispherical shape is circumferentially welded and joined to one end of the cylindrical body plate 1, and the other end of the body plate 1 has a basin plate shape. The lower end plate 2 ', which is formed by welding, is circumferentially welded and joined. In this embodiment, the welding method according to the present invention is used to join the cylindrical body plate 1 and the upper end plate 2 and the body plate 1 and the lower end plate 2'to each other to obtain a plate thickness of 2.5 m.
m, length about 500 mm, body diameter about 200 mm,
A domestic LP gas cylinder made of JIS A5083-O material was experimentally manufactured, and an X-ray inspection of the welded part of the butt one-side welded joint was conducted, and a fracture test by internal pressure was carried out to obtain the pressure resistance of the joint.

A butt and one-sided welded joint having a one-sided drawing structure composed of the cylindrical body plate 1 and the hemispherical upper end plate 2 will be described. As shown in FIG. 1, the end of the body plate 1 has a one-sided drawing structure. After the part is bent inwardly, the end part is bent along the back surface of the end plate 2, and the end face having the inclined groove face 2a is opposed to the obliquely bent bending part 1a of the body plate 1. By arranging them on the body plate 1 like this,
A butt-side one-side welded joint having a single-drawing structure in which a groove portion 3 is formed between the bending portion 1a of the body plate 1 and the groove surface having the inclined groove surface 2a of the end plate 2 is formed. The configuration of the butt one-side welded joint having the one-sided drawing structure including the body plate 1 and the lower end plate 2'is also the same. In FIG. 1, θ indicates an angle (tilt groove angle) formed by the inclined groove surface with respect to the end plate surface (horizontal plane), and d is a depth dimension of the inclined groove surface 2a from the end plate surface (inclined groove depth dimension). ) Is shown. The plate thickness t of the end plate 2 and the body plate 1 is 2.5 mm in this embodiment.

A work having such a butt-side welded joint was prepared, and the groove portion 3 was MIG welded in one pass by using the inclined groove angle θ and the inclined groove depth dimension d as parameters. Welding was performed using a semi-automatic welding machine while fixing the welding torch and rotating the work at a constant speed. The welding conditions are: welding position: downward welding, welding wire diameter: 1.
2 mm, shield gas: argon gas, welding current: about 1
00A, welding voltage: about 20V, welding speed: about 60 cm /
Minutes,

FIG. 3 is a diagram showing the relationship between the inclined groove angle and the X-ray inspection result, and the relationship between the inclined groove angle and the pressure resistance test result. In FIG. 3, the inclined groove depth dimension d is d = (3
/ 4) · t, set to a constant value, and tilt groove angle θ
The result when changing is shown. The value of the X-ray inspection grade in FIG. 3 is a value obtained by averaging the X-ray inspection grade values at a total of eight places in the upper and lower sides of the work integrated body.

As shown in FIG. 3, the value of the X-ray inspection grade showing the presence or absence of insufficient penetration of the groove portion 3, particularly the insufficient penetration at the groove root portion, is smaller than the vertical angle θ of inclination. It was improved as it became, and when it reached 60 degrees, it reached the level of the second grade which is the X-ray inspection passing line. In the region where the inclined groove angle θ is larger than 60 degrees and approaches the vertical direction, it is difficult for the arc to reach the groove root part and it is difficult to sufficiently melt the groove root part by the arc, and welding due to insufficient penetration into the groove root part It is considered that defects easily occur and the X-ray inspection grade value deteriorates. Then, in the region where the inclined groove angle θ becomes smaller than 30 degrees and the inclined groove surface 2a approaches the horizontal direction, burn-through occurs.

Further, as shown in FIG. 3, the proof pressure strength is improved between 75 ° and 60 ° when the inclined groove angle θ is smaller than 90 °, and is increased, and is almost in the range of 60 to 30 °. The base metal (non-welded part) started to break. When the inclined groove surface angle θ was smaller than 30 degrees, the welding amount was insufficient under these welding conditions, the groove portion 3 could not be completely filled, and the pressure resistance sharply decreased.

As described above, the inclined groove surface angle θ is
It has been found that the range of 60 to 30 degrees is preferable, and more preferably, the range of 60 to 45 degrees is optimal from the viewpoint of preventing a decrease in welding efficiency due to an increase in groove cross-sectional area as compared with the prior art. .

FIG. 4 is a diagram showing the relationship between the inclination groove depth dimension and the X-ray inspection result, and the relationship between the inclination groove depth dimension and the pressure resistance test result. In FIG. 4, the inclination groove angle θ is θ =
The groove depth is set to be 45 degrees and the groove depth is d
The result when changing is shown. The value of the X-ray inspection grade in FIG. 4 is a value obtained by averaging the X-ray inspection grade values at a total of eight places in the upper and lower sides of the work piece.

As shown in FIG. 4, the X-ray inspection grade value is improved as the inclined groove depth dimension d is increased, and when the inclined groove depth dimension d becomes a half of the plate thickness dimension t, it is almost the same. Two
Reached class level. Similarly, the compressive strength was improved as the inclined groove depth dimension d was increased, and almost reached the base metal strength when the inclined groove depth dimension d became half the sheet thickness dimension t.

As described above, it was found that the inclined groove depth dimension d is preferably one-half or more of the plate thickness dimension [d ≧ (t / 2)]. If d <(t / 2), the effect of forming the inclined groove surface 2a is not exerted, and it becomes difficult for the groove root portion to be sufficiently melted by the arc, and a welding defect due to insufficient penetration into the groove root portion. Is likely to occur.

As described above, the end plate 2 in this embodiment is used as the plate to be welded which does not have the refraction portion for the one-sided drawing structure.
In place of the conventional I-shaped groove surface (vertical groove surface) as it is, a groove surface having an inclined groove surface 2a is formed, and an angle θ formed between the inclined groove surface 2a and the end plate surface. 30 to 6
By setting it to 0 degree and setting the depth dimension d from the surface of the end plate to more than half of the end plate thickness, insufficient penetration or burn through of the groove 3 of the butt one side welded joint of the single drawing structure It was possible to perform MIG welding in one pass with almost no welding defects such as, and good X-ray inspection results and pressure resistance test results were obtained.

[0024]

As described above, according to the butting one-side welding method for an aluminum alloy member according to the present invention, one welded plate made of an aluminum alloy having a bent portion for forming a one-sided drawing structure and a conventional welded plate are used. Butt one-side welded joint of one-sided drawing structure with another plate to be welded made of an aluminum alloy in which a groove surface having an inclined groove surface is formed instead of the I-shaped groove surface (vertical groove surface) as it is And the groove portion formed between the bent portion and the groove surface having the inclined groove surface is MIG welded in one pass. The bottom part) can be sufficiently melted by an arc, and the groove part can be MIG welded in one pass with almost no welding defects such as insufficient penetration and burn-through. Weld defects compared to conventional methods. Need to be repaired due to Effort and time can be greatly reduced that.

[Brief description of drawings]

FIG. 1 is a diagram relating to a welding method according to the present invention, in which a joint shape of a butt one-side welded joint having a one-sided drawing structure composed of a cylindrical body plate made of an aluminum alloy and a hemispherical end plate made of an aluminum alloy ( It is a figure which shows a groove part shape.

FIG. 2 is a household L to which the welding method according to the present invention is applied.
It is a figure which shows the structure of a P gas cylinder.

FIG. 3 is a diagram showing a relationship between an inclined groove angle and an X-ray inspection result, and a relationship between an inclined groove angle and a pressure resistance test result.

FIG. 4 is a diagram showing a relationship between a slope groove depth dimension and an X-ray inspection result, and a relationship between a slope groove depth dimension and a pressure resistance test result.

FIG. 5 is a joint shape (groove portion shape) of a butt one-side welded joint having a one-sided drawing structure according to the butt one-side welding method of the present invention.
FIG.

FIG. 6 is a view showing a joint shape (groove shape) of a conventional butt-side welded joint having a single-drawing structure.

FIG. 7 is a view showing a joint shape (groove portion shape) of a conventional butt-side welded joint having another single-drawing structure.

FIG. 8 is a view showing a state where a penetration insufficient defect has occurred in a groove root portion in a butt one-side welded joint.

[Explanation of reference numerals] 1 ... Body plate 1a ... Refraction part 2 ... Upper end plate 2a ... Inclined groove face 2 '... Lower end plate 3 ... Groove part 11, 12 ...
Plate to be welded 11a ... Refraction portion 12a ... Inclined groove surface 13
… Groove θ… Inclined groove angle d… Inclined groove depth dimension

Front page continuation (72) Inventor, Ms. Hagiwara, 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Inside Kobe Steel Co., Ltd. (72) Inventor, Kazuhiro Fukuda, 112, Kaita-higashi-cho, Kurayoshi, Tottori Equipment Industry Co., Ltd. (72) Inventor Shigezo Yamazaki 112 Kaitahigashi-cho, Kurayoshi City, Tottori Prefecture Shinko Equipment Co., Ltd.

Claims (1)

[Claims] 1. One of two plates to be welded made of an aluminum alloy is bent inward at one end of the plate to be welded, and then is bent along the back surface of the other plate to be welded, and the other plate to be welded is formed. The groove surface is arranged so as to face the bent portion of the one plate to be welded that is obliquely bent, and between the bent portion of the one plate to be welded and the groove surface of the other plate to be welded. A butting one-side welded joint having a one-sided drawing structure in which a groove is formed between
In a butt piece welding method for an aluminum alloy member in which the groove portion of this welded joint is MIG-welded in one pass, the groove surface of the other welded plate is directed toward the bent portion of the one welded plate. Has an inclined groove face whose angle with the plate surface is 30 to 60 degrees and whose depth dimension from the plate surface is one-half or more of the plate thickness dimension of the other plate to be welded. A butt piece side of an aluminum alloy member, characterized in that a groove surface is formed, and the groove portion formed between the groove surface and the bending portion of the one plate to be welded is MIG welded in one pass. Welding method.