JP2509916B2 - Aluminum alloy filler metal - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aluminum alloy filler material used for welding, and more particularly to a filler material used for welding Al-Cu alloy material having a Cu content of 5 wt% or less. .

Conventional Technology and Problems Since addition of Cu is generally effective in improving the strength of aluminum alloy materials, for example, 2000-based Cu-containing aluminum alloy materials are widely used as structural materials. However, such a Cu-containing aluminum alloy material, when subjected to welding using the existing filler material, causes welding cracks due to the following reasons except for some alloys described later, and therefore as a material for a welded structure. It could not be used. That is, the weld crack susceptibility of the Al-Cu binary alloy is, as shown in the weld crack test result of FIG. 2, Cu:
Sensitive in the range of 0.3 to 5 wt%, this tendency is
It is known that it does not change even when other additive elements such as g and Zn are included. On the other hand, existing filler materials such as A535
When welding a Cu-containing aluminum alloy material using a filler metal made of A5556, A5183 aluminum alloy, A4043 aluminum alloy containing Si: 4.5 to 6.0 wt%, etc., the composition of the weld bead (from the base metal by welding) Since the filler metal composition is diluted, the bead composition is approximately (base metal composition + filler metal composition) / 2). In most cases, the above-mentioned weld crack susceptibility is in a sensitive range, resulting in a weld zone. It was impossible to use Cu-containing aluminum alloy as a welded structural material because of the fact that cracks occur in the steel and the strength of the welded part becomes insufficient depending on the type of filler metal. However, Cu is 5w
Aluminum alloys containing more than t%, eg C
u: A2219 aluminum alloy containing 5.8 to 6.8 wt% is the same as Cu: 5.8 to 6.8 wt% eutectic A2319.
By using aluminum alloy as a filler metal,
Since the Cu content of the weld bead can be made higher than 5 wt%, it has been partially used as a welded structural material. However, for Al-Cu alloys with a Cu content of 5 wt% or less, even if the above A2319 alloy is used as a filler metal, welding cracks will occur, and it is still impossible to use it as a material for welded structures. Met.

The present invention has been made in view of such a background, Cu content is 5 wt% or less, Al-Cu-based alloy material, to improve its weld cracking susceptibility, as a material for a welded structure of the material The purpose of the present invention is to provide an aluminum alloy filler material that can be used.

MEANS FOR SOLVING THE PROBLEMS Thus, the present invention is directed to Al-Cu having a Cu content of 5 wt% or less.
A filler metal for welding alloys containing Cu, containing more than 7 wt% and less than 15 wt% Cu, or Mn: 0.05 to 1.5
wt%, Cr: 0.01 to 0.5 wt% and / or at least one of
Zr: 0.01-1.0wt%, Ti: 0.005-0.2wt%, B: 0.001-0.01
The gist of the present invention is an aluminum alloy filler material containing one or two or more wt% and the balance being aluminum and inevitable impurities.

Cu as an essential component in the filler metal has a Cu content of 5 wt%
For Al-Cu alloy materials that are below, the Cu content in the composition of the weld bead is set to 0.3-5 wt
It is necessary to set it outside the range of%. As described above, the bead composition is approximately (base material composition + filler material composition) / 2, so the Cu content of the base aluminum alloy material is 0.6w.
When it is t% or more, it is impossible to suppress the Cu content of the bead to less than 0.3 wt%. For this reason, the Cu content of the bead needs to be greater than 5 wt%, but when the Cu content of the bead is around 5 wt%, instability remains in the weld cracking susceptibility, so 6 wt% or more is desirable. When the Cu content in the base metal is 5 wt%, the Cu content in the filler metal needs to be 7 wt% to make the Cu content in the bead 6 wt%. From this viewpoint, the lower limit of the Cu content in the filler metal is 7 wt%. % Was exceeded. On the other hand, the upper limit of the Cu content in the filler metal is set to 15 wt% because when the content exceeds 15 wt%, the Cu content in the weld bead always exceeds 6 wt% regardless of the Cu content in the base metal. This is because not only the joint strength is lowered, but also the workability is lowered, which makes it difficult to manufacture the filler metal itself.

For the filler material, in addition to the above Cu, Mn: 0.05 to 1.5 wt
%, Cr: 0.01 to 0.5 wt%, either or both of them are allowed. Both Mn and Cr contribute to improving the corrosion resistance and strength of the weld. However, Mn is less than 0.05 wt%,
If Cr is less than 0.01 wt%, these effects are poor, and conversely Mn is
If it exceeds 1.5 wt%, coarse intermetallic compounds crystallize and hinder the toughness. Further, even if Cr is contained in an amount exceeding 0.5 wt%, the toughness is impaired.

Furthermore, regardless of whether or not the above Mn and Cr are contained in the filler metal, Zr: 0.01 to 1.0 wt%, Ti: 0.005 to 0.2 wt%, B: 0.001 to
The content of one or more of 0.01 wt% is allowed. Z
r, Ti, and B all contribute to the improvement of weld crack susceptibility by refining the crystal grains. However, Zr is less than 0.01 wt%,
When Ti is less than 0.005 wt% and B is less than 0.001 wt%, the effect is poor. Conversely, when Zr exceeds 1.0 wt% and Ti exceeds 0.2 wt%, toughness is impaired, and B is 0.01 wt%. If it exceeds%, the flowability of the molten metal to be welded is hindered.

The filler material is generally used as a welding rod and an electrode wire having a diameter and tolerance defined in JIS Z3232.

As described above, the aluminum alloy filler material according to the present invention contains Cu in an amount of more than 7 wt% and 15 wt% or less, so that the Cu content is 5 wt% or less. With respect to the above welding, the Cu content in the composition of the weld bead can be forced to fall outside the sensitive range of weld cracking susceptibility. As a result, the Cu content was increased by using this filler metal.
Welding of Al-Cu alloy materials with 5 wt% or less is possible,
Therefore, it becomes possible to use the material as a welded structural material,
The range of use of the material can be remarkably expanded.

EXAMPLES Next, examples of the present invention will be described.

A test piece composed of a base material having the composition shown in Table 1 above, and a second
A MIG fishbone cracking test was carried out using various filler materials having a composition shown in the table and having a diameter of 1.6 mm. Test piece (1) is first
As shown in the figure, thickness: 6 mm, length (L): 250 mm, width (W): 200 mm, slit (ia) interval (l): 10 mm,
(Y): 10 mm. Note that (2) is a tab plate. The test was carried out under the following welding conditions in the direction indicated by the arrow (X) in FIG.
Welding was performed to measure the crack length of the welded portion (3), and the crack rate was obtained.

Welding conditions Current: 220A Voltage: 28V Welding speed: 40cm / min The test was conducted 4 times each. The results are shown in Table 3.

As is clear from the above results, it was confirmed that when the filler material according to the present invention was used, weld cracking of the base material containing Cu was unlikely to occur.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a weld crack test piece, and FIG. 2 is a graph showing the relationship between the Cu content in the base metal and the weld crack length. (1) …… Test piece, (ia) …… Slit, (2) …… Tab plate, (3) …… Welded part.

Claims (2)

(57) [Claims] 1. A filler metal for welding to an Al-Cu alloy material having a Cu content of 5 wt% or less, Cu: more than 7 wt% and 15 wt%
% Or less, with the balance being aluminum and inevitable impurities, an aluminum alloy filler material. 2. A filler metal for welding to an Al-Cu alloy material having a Cu content of 5 wt% or less, Cu: more than 7 wt% and 15 wt%
% Or less, Mn: 0.05 to 1.5 wt%, Cr: 0.01 to
At least one of 0.5 wt% and / or Zr: 0.01 to 1.0 wt
%, Ti: 0.005 to 0.2 wt%, B: 0.001 to 0.01 wt%, or a mixture of two or more, and the balance being aluminum and unavoidable impurities.