KR20200060925A - Filler Wire for Tailor Welded Blank and Method for Tailor Welded Blank using the Same - Google Patents

Abstract

The present invention relates to a Taylor blank welding filler wire capable of ensuring excellent robustness and formability of a weld part, and a Taylor blank welding method using the same. The Taylor blank welding filler according to one embodiment of the present invention, as a filler wire used for Taylor blank welding, contains: 7.0 to 9.0 wt% of magnesium (Mg); 0.2 to 1.0 wt% of copper (Cu); and the balance aluminum (Al) and other unavoidable impurities.

Description

Filler wire for Taylor blank welding and Taylor blank welding method using the same {Filler Wire for Tailor Welded Blank and Method for Tailor Welded Blank using the Same}

The present invention relates to a filler wire for Taylor blank welding and a Taylor blank welding method using the same, and more particularly, a Taylor blank welding filler wire which can securely secure the robustness and formability of a welded portion and a Taylor blank welding method using the same It is about.

Recently, in the automobile industry, studies to reduce the weight of the vehicle body have been continuously conducted to improve fuel efficiency and reduce exhaust gas.

In order to achieve the weight reduction of the vehicle body, a light weight material application technology is being actively developed to replace the existing steel plate material applied to the vehicle body parts, and among the light weight materials, aluminum is in the spotlight.

Aluminum has rich reserves, only about 35% of iron (steel sheet), and has excellent corrosion resistance. However, aluminum has a disadvantage in that its strength is lower than that of a steel sheet, and thus there is a limit to replacing the steel sheet as it is using aluminum. For example, in order to realize a vehicle body having the same strength as a steel plate by using aluminum, the vehicle body must be manufactured with a thickness of 1.5 to 2 times that of the steel plate, thereby reducing the weight reduction rate.

On the other hand, in order to maximize the weight reduction ratio, recently, technology development to apply the optimum thickness for each part by calculating the required performance for each part has been actively conducted, and the Taylor Welded Blank (TWB) technology has received the most attention. have.

Taylor welded blank technology is a technology that bonds dissimilar plates of different materials and thicknesses with lasers, and then molds them into parts, which have already been applied to parts such as door inner plates.

However, in the case of aluminum, many defects such as pores and thermal cracks occurred during welding, which made it difficult to manufacture, and research to overcome this has been continued.

The above descriptions as background arts are only for improving the understanding of the background of the present invention, and should not be accepted as acknowledging that they correspond to the prior arts already known to those skilled in the art.

Registered Patent Publication No. 10-0551797 (2006.02.06)

The present invention provides a Taylor blank welding filler wire and a Taylor blank welding method using the filler wire for securing the robustness and formability of a welded portion.

The filler wire for Taylor blank welding according to an embodiment of the present invention is a filler wire used for Taylor blank welding, magnesium (Mg): 7.0 to 9.0 wt%, copper (Cu): 0.2 to 1.0 wt%, and the remaining aluminum ( Al) and other inevitable impurities.

The filler wire further contains iron (Fe): 0.2 wt% or less.

The filler wire is characterized in that it is used for Taylor blank welding of 5000-based aluminum alloy.

The filler wire is characterized in that it is used for Taylor blank welding of inner plate parts for automobiles.

Meanwhile, the filler wire for Taylor blank welding according to an embodiment of the present invention is a filler wire used for Taylor blank welding, magnesium (Mg): 7.0 to 9.0 wt%, copper (Cu): 0.2 to 1.0 wt%, iron (Fe): 0.2 wt% or less (excluding 0 wt%), remaining aluminum (Al), and other inevitable impurities.

In addition, the Taylor blank welding method according to an embodiment of the present invention is magnesium (Mg): 7.0 ~ 9.0wt%, copper (Cu): 0.2 ~ 1.0wt%, iron (Fe): 0.2wt% or less (excluding 0wt% ), preparing a filler wire for Taylor blank welding containing the remaining aluminum (Al) and other inevitable impurities; Preparing a sheet of aluminum alloy; And butt-welding the plate material using the filler wire.

The plate material is characterized by being prepared with a 5000-based aluminum alloy.

According to an embodiment of the present invention, the elongation and strength of the base material level can be secured even in a welding portion when welding a plate material made of a 5000-based aluminum alloy.

Through this, an aluminum taylor welded blank can be applied to the body parts to maximize weight reduction through optimization of the thickness of each part.

1 is a photograph showing the fracture behavior according to the tensile test of the embodiments to which the filler wire according to the present invention is applied,
Figure 2 is a photograph showing the fracture behavior according to the tensile test of the comparative examples,
Figure 3 is a photograph showing a cross-section of the welding portion of the embodiments to which the filler wire according to the present invention is applied,
4 is a photograph showing a cross-section of a weld of comparative examples.
5 is a photograph showing a microstructure of a welding part of an embodiment to which a filler wire according to the present invention is applied.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the present embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art is completely It is provided to inform you.

The filler wire for Taylor blank welding according to the present invention is a filler wire used for Taylor blank welding of a plate made of 5000 aluminum alloy for use as an inner plate part for automobiles. It is a filler wire that can secure strength.

Specifically, a filler wire containing magnesium (Mg): 7.0 to 9.0 wt%, copper (Cu): 0.2 to 1.0 wt%, and the remaining aluminum (Al) and other inevitable impurities is targeted. At this time, the filler wire may further contain iron (Fe): 0.2 wt% or less.

The reasons for limiting the ingredients and their compositional range in the present invention are as follows.

Magnesium (Mg): 7.0 ~ 9.0wt%

Magnesium (Mg) serves to improve mechanical strength and elongation due to the solid solution effect.

When the content of magnesium (Mg) is less than 7.0wt%, the effect of increasing moldability is negligible, and when it exceeds 9.0%, it is over-dissolved to degrade moldability.

Therefore, the content of magnesium (Mg) is limited to 7.0 ~ 9.0wt% range.

Copper (Cu): 0.2 ~ 1.0wt%

Copper (Cu) exhibits aging characteristics and serves to improve mechanical properties.

When the content of copper (Cu) is less than 0.2 wt%, the effect of improving the mechanical properties is negligible, and when it exceeds 1.0 wt%, compounds such as Cu ₂ Al are excessively precipitated, resulting in poor formability.

Therefore, the content of copper (Cu) is limited to the range of 0.2 to 1.0 wt%.

Iron (Fe): 0.2 wt% or less (excluding 0 wt%)

Iron (Fe) is an element contained as an impurity in the filler wire, and even in a very small amount, an Al ₃ Fe compound is formed to degrade mechanical properties.

Therefore, the maximum content of iron (Fe) is limited to 0.2 wt%.

On the other hand, the remainder other than the above-mentioned components is aluminum (Al) and other inevitable impurities.

On the other hand, in the present invention, a Taylor blank welding is performed using a filler wire having a composition as described above to produce a plate material made of 5000-based aluminum alloy for manufacturing an automobile inner plate part.

To this end, as described above, magnesium (Mg): 7.0 to 9.0 wt%, copper (Cu): 0.2 to 1.0 wt%, iron (Fe): 0.2 wt% or less (excluding 0 wt%), remaining aluminum (Al) and A filler wire for Taylor blank welding containing other unavoidable impurities is prepared.

Then, a plate material is prepared from a 5000-based aluminum alloy.

The 5000-based aluminum alloy is an aluminum alloy that has high strength and good moldability, and is applied as a body part.

When the plate material and the filler wire are prepared in this way, the plate material is butted and then welded using the filler wire. At this time, the welding source for melting the filler wire uses an arc or a laser, and a single beam or a dual beam may be applied to the beam shape during welding. Of course, the beam shape is not limited to this, and may be applied by being variously changed in consideration of the shape and thickness of the welding object.

Hereinafter, the present invention will be described using examples and comparative examples.

Filler wire was prepared with the components shown in Table 1 below. And the base material was made of a plate material using A5182, a 5000-based (Al-Mg-based) aluminum alloy material applied to an automobile inner plate, and after welding two base metals using a laser, the elongation and tensile strength were measured. The results are shown in Table 1 and FIGS. 1 and 2.

In addition, cross-sections of welds of Examples and Comparative Examples were observed, and the results are shown in FIGS. 3 and 4. Then, the microstructure of the weld part of the example was observed, and the results are shown in FIG. 5.

On the other hand, the elongation of the base material itself used in the test was about 26 to 27%.

division Filler wire composition (wt%) Elongation
(%) burglar
(MPa) Mg Cu Fe Example 1 7 0.2 0.2 27.1 283 Example 2 9 0.2 0.1 26.5 279 Example 3 8 0.7 0.2 26.8 283 Example 4 9 0.7 0.1 26 278 Example 5 9 One 0.1 26.4 280 Comparative Example 1 6 0.7 0.2 24.1 243 Comparative Example 2 10 One 0.2 21.8 224 Comparative Example 3 10 0.7 0.1 22 222 Comparative Example 4 9 1.2 0.2 15.7 211 Comparative Example 5 7 0.1 0.1 24.3 247 Comparative Example 6 7 0.2 0.3 18.5 215

As can be seen from Table 1, Examples 1 to 5 are specimens welded using filler wires satisfying the content defined in the present invention, and the elongation of the specimen formed by the weld is secured to a level similar to the elongation of the base material itself. I could confirm what I could do. In particular, as can be seen in Figure 1, during the tensile test, it was confirmed that the fracture did not occur in the weld but the fracture occurred in the base material. The reason for showing this result is that Mg and Cu are employed in the welding portion, and thus the strength is improved, so that the welding portion does not break, and it is considered that the fracture occurred in a relatively soft base material.

In addition, as shown in FIG. 3, in the specimens of the examples, heat cracks and pores were not generated in the weld.

In addition, as shown in FIG. 5, as a result of observing the microstructure of the welded portion of the example specimen, a dendrite structure such as a general welded portion was observed, and specific features such as defects were not found.

However, Comparative Examples 1 to 6 were specimens welded using filler wires that did not satisfy the content defined in the present invention, and it was confirmed that the elongation of the specimen formed with the weld was lower than that of the base material itself.

When the Mg content and the Cu content were lower than the suggested content, the elongation of Comparative Example 1 and Comparative Example 5 was about 24%, which was lower than that of the base material.

In addition, as shown in FIG. 2, as a result of observing the fracture behavior of the comparative examples, the fracture of the base material and the fracture of the weld part occurred simultaneously in Comparative Example 1 and Comparative Example 5. These results indicate that the strength of the weld zone was insignificant due to the low Mg and Cu content, and thus it was found to break prematurely.

In addition, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 6, in which the Mg content, the Cu content, and the Fe content were higher than the suggested content, the elongation was 22% or less, significantly lower than that of the base material.

In addition, as shown in FIG. 2, as a result of observing the fracture behavior of the comparative examples, the interface fracture of the weld zone occurred in Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 6. As a result of this, it is judged that the elongation and strength of the weld zone are lowered as the Mg is over-dissolved, the Cu precipitate is excessively formed, and the Al ₃ Fe compound is formed, resulting in fracture at the weld zone.

In addition, as can be seen in FIG. 4, in Comparative Example 4, heat cracks were generated in the welding portion, and in Comparative Example 6, micropores were generated in the welding portion.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto, but is limited by the claims below. Therefore, those of ordinary skill in the art can variously modify and modify the present invention without departing from the technical spirit of the claims to be described later.

Claims (7)

As filler wire used for Taylor blank welding,
Magnesium (Mg): 7.0 to 9.0 wt%, copper (Cu): 0.2 to 1.0 wt%, filler wire for Taylor blank welding containing the remaining aluminum (Al) and other unavoidable impurities.
The method according to claim 1,
The filler wire is iron (Fe): Taylor blank welding filler wire further contains 0.2wt% or less.
The method according to claim 1,
The filler wire is a filler wire for Taylor blank welding, characterized in that used for Taylor blank welding of 5000-based aluminum alloy.
The method according to claim 3,
The filler wire is a Taylor blank welding filler wire, characterized in that is used for Taylor blank welding of inner plate parts for automobiles.
As filler wire used for Taylor blank welding,
Magnesium (Mg): 7.0 to 9.0 wt%, Copper (Cu): 0.2 to 1.0 wt%, Iron (Fe): 0.2 wt% or less (excluding 0 wt%), Taylor blank consisting of the remaining aluminum (Al) and other inevitable impurities Filler wire for welding.
Magnesium (Mg): 7.0 to 9.0 wt%, Copper (Cu): 0.2 to 1.0 wt%, Iron (Fe): 0.2 wt% or less (excluding 0 wt%), Taylor containing the remaining aluminum (Al) and other unavoidable impurities Preparing a filler wire for blank welding;
Preparing a sheet of aluminum alloy;
Taylor blank welding method comprising the step of butt welding the plate material using the filler wire.
The method according to claim 6,
Taylor blank welding method, characterized in that the plate material is prepared from a 5000-based aluminum alloy.

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