JP3352913B2 - MIG wire for welding aluminum or aluminum alloy material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MIG wire used for welding aluminum or aluminum alloy material, and more particularly to a MIG wire for welding aluminum or aluminum alloy material capable of improving wire feedability and arc stability.

[0002]

2. Description of the Related Art When aluminum or an aluminum alloy material is subjected to MIG welding, it is necessary to improve blowhole resistance and wire feedability in order to obtain a good weld.

That is, since aluminum or aluminum alloy has a large difference in hydrogen solubility between a liquid phase and a solid phase, blowholes are particularly likely to occur in a welded portion thereof.
Therefore, it is known that reducing the amount of hydrogen present in an aluminum or aluminum alloy wire can improve the resistance to blowholes. For example, a wire that appropriately defines the position of hydrogen in the wire has been disclosed. (JP-A-6-246480).

[0004] As described above, regarding the blowhole resistance, the occurrence frequency of blowholes can be reduced by grasping the location of hydrogen in the wire and adjusting the manufacturing process of the wire.

On the other hand, in an actual welding site, since a semi-automatic welding having a strict feed system and welding are performed using a multi-joint robot, recently, even in such a strict feed system, It is an important issue to obtain a method capable of feeding a wire at a constant speed during welding. This is because when a wire feeding failure occurs, a stable welded portion cannot be formed, resulting in poor fusion and meandering of the beads. Therefore, a wire has been proposed in which a fluorine derivative of polyether, which is a feed lubricating oil having no hydrogen atoms, is attached to the surface of the wire to improve the feedability (JP-A-6-114590). .

[0006]

However, even with the use of the wire described in Japanese Patent Application Laid-Open No. 6-114590, since the feeding system has become severe due to the recent spread of welding robots, a stable arc has been obtained. It is difficult to obtain continuously.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an aluminum or aluminum alloy welding MIG wire capable of improving both wire feedability and arc stability. I do.

[0008]

According to the present invention, there is provided a MIG wire for an aluminum or aluminum alloy material, comprising a fluorine derivative of polyether which is liquid at room temperature and having a diameter of 50 to 20.
It is characterized in that it is attached to the wire surface in the state of droplets of 0 μm at an attachment density of 20 to 80 (pieces / mm ² ).

The diameter of the fluorine derivative of the polyether is preferably 100 to 150 μm.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain a wire capable of improving the wire feedability even in a severe feed system, the present inventors increased or decreased the amount of the polyether fluorine derivative attached to the wire surface. Then, the range of the appropriate adhesion amount was examined. Hereinafter, the fluorine derivative of the polyether is referred to as fluoro oil.

FIG. 1 is a graph showing the effect of the wire feedability and arc stability on the change in the amount of adhered fluorine oil on the surface of the wire. In FIG. 1, a solid line 1 indicates the wire feedability, and the smaller the amount of fluorine oil adhering to the wire surface, the more a defective feed occurs in a severe feed system. On the other hand, the solid line 2 shows the stability of the arc, and the more the amount of fluorine oil attached to the wire surface, the more unstable the arc. Therefore, as shown in FIG. 1, it is not possible to improve both the wire feedability and the arc stability only by adjusting the amount of adhesion, and the appropriate range of the amount of adhesion of fluorine oil to the wire surface is not sufficient. Could not be found.

By the way, when the amount of fluorine oil adhering to the wire surface is small, the wire feedability is reduced because:
This is because the frictional resistance due to the contact between the welding conduit tube and the wire increases. Therefore, if the amount of the adhered fluorine oil is small, the wire is not smoothly fed in a severe feeding system. In addition, when the amount of the adhered fluorine oil is large, the wire is fed smoothly, but since a thick insulating film is formed on the surface of the wire, power supply between the current-carrying chip and the wire is hindered. Arc becomes unstable.

[0013] The inventors of the present invention have conducted various studies in order to obtain a wire capable of improving both the wire feedability and the arc stability. First, the relationship between the amount of fluorine oil deposited on the wire surface and the form of deposition was investigated. FIG. 2 is a diagram showing a result of analyzing the wire surface by infrared spectroscopy when a fluorine oil is adhered to the wire surface by a coating method using felt. This is a method in which a solution of fluoro oil diluted with a diluent such as chlorofluorocarbon is impregnated into a felt, and the felt is rubbed against the surface of the wire to apply the fluoro oil to the surface of the wire (Japanese Utility Model Application Laid-Open No. 3-116274). Gazette).

FIG. 3 is a diagram showing the result of analysis of the wire surface by infrared spectroscopy when fluorine oil is adhered to the wire surface by the rotary electrostatic atomization coating method.
The rotary electrostatic atomization coating method is to supply a solution to be applied into a bell cup to which a high voltage is applied, and to rotate and rotate the bell cup to atomize and charge the coating particles (fluoro oil). And the object to be coated (wire) at the opposite electrode
Is a method of applying paint particles to the surface (Japanese Patent No. 2578556).
issue).

In FIGS. 2 and 3, the wave number is plotted on the X axis and the distance from a predetermined position on the wire surface is plotted on the Y axis.
Absorbance is taken on the Z axis. In this example, the measurement of the absorbance was performed using a micro FT manufactured by PerkinElmer.
An -IR (microscopic Fourier transform infrared spectroscopy) device was used.

When a fluorine oil is analyzed by infrared spectroscopy, an absorption peak usually appears in a region of 1000 to 1300 cm ^-1 . In FIG. 2, an absorption peak with non-uniform intensity exists in this region regardless of the measurement position. As described above, when the fluorine oil is applied to the wire surface by the conventional application method, the entire area of the wire surface is unevenly covered with the fluorine oil. The difference in the amount of adhesion can be evaluated based on the thickness of the fluorine oil present on the wire surface.

On the other hand, in FIG. 3, a peak indicating fluoro oil appears only at a certain position. That is, when the fluorine oil is adhered to the wire surface by the rotary electrostatic atomization coating method, the adhesion is different from that shown in FIG. 2, and a region where the fluorine oil exists and a region where the fluorine oil does not exist are formed. As a result, the inventors of the present application focused on optimizing the form of attachment of the fluoro oil to the wire surface as a method for improving both the arc stability and the wire feedability.

Therefore, the inventors of the present invention presuppose, as a prerequisite, that the total amount of fluorine oil adhered to the wire surface should be constant,
Various coating methods were studied in order to change only the adhesion form. As a result, it has been found that the form of adhesion can be changed depending on the application method. Also,
As a result of evaluating the welding workability of the wire in which the fluorine oil is adhered to the surface in various forms, if the adhesion form of the fluorine oil adhering to the wire surface is appropriately regulated, the welding workability,
That is, it has been found that both the arc stability and the wire feeding property can be improved.

FIG. 4 (a) is a cross-sectional view showing the form of attachment of fluorine oil on the surface of a wire which can provide excellent welding workability, and FIG. 4 (b) shows the state of attachment of fluorine oil on the surface of a conventional wire. It is sectional drawing. As shown in FIG. 4A, the surface of the wire 11a having excellent welding workability is attached with the fluorine oil 12a in a droplet state. That is, the fluoro oil 12a does not cover the entire surface of the wire 11a, but is scattered at a desired density on the wire surface.

On the other hand, as shown in FIG. 4B, on the surface of the conventional wire 11b, as described above, the fluoro oil 12b is unevenly present over the entire surface.

As described above, the present invention is intended to improve the welding workability by adhering fluorine oil to the wire surface in the form of droplets and appropriately regulating the adhering density. In order to adjust the adhesion form of the fluorine oil on the wire surface as described above, the method of applying the fluorine oil may be appropriately selected. For example, when a rotary electrostatic atomization application method is used, a desired adhesion form is obtained. Fluorine oil can be applied to the wire surface.

The reason for limiting the diameter and the adhesion density of the droplet-like fluorine oil present on the surface of the MIG wire for welding aluminum or aluminum alloy material according to the present invention will be described below.

Diameter of droplet-like fluoro oil: 50 to 200 μm
When a predetermined amount of fluoro oil is applied to the wire surface, if the diameter of the droplet-shaped fluoro oil is less than 50 μm or the diameter exceeds 200 μm, the wire surface is uniformly covered with the applied fluoro oil. Therefore, the form of adhesion of the fluoro oil on the surface of the wire is the same as the case of applying by a conventional application method. As a result, it becomes difficult to improve both the wire feedability and arc stability. Therefore, the diameter of the droplet-like fluorine oil is set to 50 to 200 μm. Preferably, the diameter of the fluoro oil is 100 to 150 μm.

Adhesion density of droplet-like fluorine oil: 20 to 80
(Pieces / mm ² ) The adhesion density is 20
If the number is less than (pieces / mm ² ) or exceeds 80 (pieces / mm ² ), the form of adhesion of the fluoro oil on the wire surface is
It is equivalent to the case of applying by the conventional application method. As a result, it becomes difficult to improve both the wire feedability and arc stability. Therefore, the adhesion density of the droplet-like fluorine oil is set to 20 to 80 (pieces / mm ² ).

When a rotary electrostatic atomizing coating method is used as a method for attaching the fluorine oil to the wire surface, the voltage applied to the bell cup of the rotary electrostatic atomizing coating apparatus, the number of rotations of the bell cup and By adjusting the supply amount of the fluorine oil, the diameter and the adhesion density of the droplet-like fluorine oil can be regulated as described above.

For example, when the voltage applied to the bell cup is increased, the adhesion density of the droplet-like fluoro oil can be increased. Therefore, usually, the voltage is from 2 to 3000 V to tens of thousands V
It is preferable that even if the voltage is further increased, the effect of increasing the adhesion density of the droplet-like fluorine oil on the wire surface decreases. Also, the higher the rotation speed of the bell cup,
Since the diameter of the droplet-like fluoro oil becomes small, it is usually 4 to 5
The rotation is preferably from 000 to 20,000 to 30,000. The number of rotations can be increased to 30,000 or more, but in this case, the mechanical wear of the rotating part is significantly increased, which is not preferable.

Further, when the rotational speed of the bell cup is constant, the diameter of the droplet-like fluorine oil increases as the supply amount of the fluorine oil increases. In addition to these factors, factors that affect the diameter and the adhesion density of the droplet-like fluorine oil include the shape of the bell cup, the shape of the booth of the coating device, the shape of the air flow in the booth of the coating device, and the bell cup and wire. There is a positional relationship. Therefore, by appropriately adjusting these factors, it is possible to control the diameter and the adhesion density of the droplet-like fluorine oil.

In the present invention, in addition to the rotary electrostatic atomizing coating method, a spray type electrostatic coating is also used.
Droplet-like fluorine oil can be attached to the wire surface with a desired diameter and attachment density. Further, it is also possible to use a method of applying fluorine oil using an atomizing nozzle, a method of applying fluorine oil dripping from a needle point to which a high voltage is applied, and atomizing and applying the fluorine oil. . In particular, when the rotary electrostatic atomization coating method is used, it is possible to further improve the penetrability of the fluoro oil into the wire (the spreadability), that is, the uniformity of the adhesion density of the fluoro oil in various regions of the wire surface. Can be improved.

In the present invention, the existence form and adhesion density of the fluorine oil adhered to the wire surface can be evaluated by observation with an optical microscope. The component identification of the fluoro oil can be performed by the micro FT-IR device.

[0030]

EXAMPLES Examples of the MIG wire for welding aluminum or aluminum alloy material according to the present invention will be specifically described below in comparison with comparative examples.

First, a wire material (JIS Z3232 A5356WY) having a diameter of 1.6 mm is prepared, and fluorine oil (fluorine derivative of polyether) is applied to the surface of the wire material using a rotary electrostatic atomizer. Was applied to prepare a MIG wire. In this embodiment, the diameter and the adhesion density of the droplet-like fluorine oil to be attached to the wire surface are changed by controlling the voltage, the number of revolutions, and the supply amount of the polyether fluorine derivative of the rotary electrostatic atomizing coating device. I let it.

Next, a welding test for evaluating arc stability and wire feedability was performed by continuously performing welding using these wires for 5 minutes by a bead-on-plate method. However, MIG welding conditions are as follows:
Using a water-cooled straight torch, the wire protrusion length was 15 mm. The welding current is 250 A and the voltage is 3
0 V was applied.

Table 1 below shows the results of the evaluation of the diameter and the adhesion density, the arc stability, and the wire feedability of the fluorinated droplet oil. However, in the evaluation results column of arc stability and wire feedability in Table 1 below, ◎ indicates extremely good, 、 indicates good, △ indicates slightly poor, and × indicates poor.

[0034]

[Table 1]

As shown in Table 1 above, Example No. In Nos. 1 to 6, since the diameter and the adhesion density of the droplet-like fluorine oil were appropriately regulated, the arc stability and the wire feeding property were excellent. In particular, in Example No. In Nos. 1 to 4, since the diameter of the droplet-like fluorine oil was within the preferable range specified in the present invention, the arc stability and the wire feedability were further improved.

On the other hand, in Comparative Example No. Reference numeral 7 denotes a conventional wire, in which fluorine oil is present on the entire surface of the wire.
The arc stability and wire feedability were slightly reduced as compared to the examples. Comparative Example No. In No. 8, the diameter of the fluorinated droplet oil was within the range of the present invention, but the wire feeding property was lowered because the adhesion density was less than the lower limit of the range of the present invention. Comparative Example No. In No. 9, the adhesion density of the droplet-like fluorine oil was within the range of the present invention, but the diameter exceeded the upper limit of the range of the present invention, so that the arc stability was lowered.

Comparative Example No. In No. 10, the diameter of the fluorinated droplet oil was within the range of the present invention, but since the adhesion density exceeded the upper limit of the range of the present invention, the arc stability was lowered. Comparative Example No. In No. 11, although the adhesion density of the droplet-like fluorine oil was within the range of the present invention, the wire feeding property was reduced because the diameter was less than the lower limit of the range of the present invention.

[0038]

As described in detail above, according to the present invention,
Since the fluorine derivative of polyether, which is liquid at room temperature, is attached in droplet form on the surface of the MIG wire for welding aluminum or aluminum alloy material, the diameter and the attachment density are appropriately specified. In addition, the arc stability at the time of welding can be improved as well as the arc resistance.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graph showing the amount of fluorine oil deposited on a wire surface on the horizontal axis, and showing the influence of wire feedability and arc stability on the change in the deposited amount.

FIG. 2 is a diagram showing a result of analyzing the wire surface by infrared spectroscopy when a fluorine oil is adhered to the wire surface by a coating method using a felt.

FIG. 3 is a view showing the result of analyzing the wire surface by infrared spectroscopy when fluorine oil is adhered to the wire surface by a rotary electrostatic atomization coating method.

FIG. 4 (a) is a cross-sectional view showing a form of attachment of fluorine oil on a wire surface capable of obtaining excellent welding workability, and FIG. 4 (b) is a cross-section showing a form of attachment of fluorine oil on a conventional wire surface. FIG.

[Explanation of symbols]

 11a, 11b; wire 12a, 12b; fluorinated oil

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-277877 (JP, A) JP-A-6-114590 (JP, A) JP-A-6-106129 (JP, A) JP-A-3-106 66495 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 35/02 B23K 35/36 B23K 35/40

Claims (2)

(57) [Claims] 1. A fluorine derivative of polyether, which is liquid at normal temperature, is attached to the wire surface in a droplet state having a diameter of 50 to 200 μm at an adhesion density of 20 to 80 (pieces / mm ² ). MIG wire for welding aluminum or aluminum alloy material. 2. The MIG wire for welding aluminum or aluminum alloy material according to claim 1, wherein the diameter of the fluorine derivative of the polyether is 100 to 150 μm.