JPS635195B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is an aluminum alloy that has good toughness and weldability, and has excellent corrosion resistance, especially no difference in color tone between the Al-Mg-Si aluminum alloy base material for drawing and the welded part. It relates to alloy filler metals. (Prior art and its problems) In recent years, lightweight structures have been desired in buildings, and as a result, Al-Mg alloys or Al-Zn-
Mg-based alloy materials for welded structures are widely used. In addition, in order to save man-hours in assembling structures, designs that use many large shapes are being adopted, and as a result, the use of Al-Mg-Si alloy materials with good extrudability is increasing. Conventionally, Al-
Aluminum alloy filler metals such as Si-based 4043 or Al-Mg-based 5356, 5556, and 1583 are used.
All of these filler metals have good weldability, but when Al-Si alloy filler metals are used to weld Al-Mg-Si alloys, the weld metal part is inferior to the base metal in terms of toughness. It was hot. Also, Al-Mg-Si
When Al--Mg type alloy filler metal is used for welding Al-Mg type alloys, there is a drawback that the welded area turns black and gray when an unpainted structure is used for a long period of time, which significantly impairs the appearance. (Means for Solving the Problems) As a result of intensive research aimed at improving the above drawbacks, the present invention has been developed to improve the toughness and mechanical performance of welded parts in welding Al-Mg-Si alloy base metals for drawing. We have discovered an excellent aluminum alloy filler material that has excellent properties and no difference in color tone between the base material and the welded part.
That is, the present invention is a filler metal for welding an Al-Si-Mg alloy for drawing, which contains 1.0 to 5.0 wt% of Si and 0.5 to 3.0 wt% of Mn.
%, Ti0.01~0.3wt%, B0.0001~0.01wt% are essential components, and this includes Cr0.01~0.2wt% and Zr0.05~
Contains 0.3wt% of either one or both of them, and the remainder
It is made of Al. (Function) In the present invention, by adding Si to Al
Hardens Al alloy and improves the strength of welded joints.
Furthermore, by adding Mn, the strength of the welded joint is further improved, and by adding Ti and B, the crystal grains of the deposited metal are made finer and the susceptibility to weld cracking is reduced. Furthermore, the addition of Cr and/or Zr reduces stress corrosion cracking susceptibility and improves corrosion resistance. The reason for limiting Si to 1 to 5wt% is that 1wt%
If it is less than 5wt%, sufficient strength in the welded part cannot be obtained and weld cracking is likely to occur, and if it exceeds 5wt%, the toughness of the welded part tends to decrease and the corrosion resistance, especially the color tone difference with the base metal, tends to be impaired. . Also, Mn
The reason why it is limited to 0.5 to 3wt% is that if it is less than 0.5wt%, it will have little effect on improving the strength of the weld, and if it exceeds 3wt%, it will form a coarse intermetallic compound with Al, reducing the toughness of the weld. It is. Also, Ti
The reason why it is limited to 0.01 to 0.3 wt% is that if it is less than 0.01 wt%, the effect of refining grains and reducing weld cracking susceptibility will be weak, and if it exceeds 0.3 wt%, it will reduce the toughness of the weld. Also, B from 0.0001
The reason for limiting the content to 0.01wt% is that if it is less than 0.0001wt%, it will not be effective in refining the grains of the weld and reducing the susceptibility to weld cracking, and if it exceeds 0.01wt%, it will inhibit the fluidity of the molten metal and reduce the toughness of the welded metal. decreases. Also, the reason for limiting Cr to 0.01 to 0.2wt% is
If it is less than 0.01wt%, the effect of improving stress corrosion cracking and corrosion resistance of the welded part will be weak, and if it exceeds 0.2wt%, Al
This forms a coarse intermetallic compound with the metal and impairs the toughness of the weld. Furthermore, the reason why Zr is limited to 0.05 to 0.3 wt% is that if it is less than 0.05 wt%, it will have little effect on improving the stress corrosion cracking and corrosion resistance of the weld, and if it exceeds 0.3 wt%, it will impair the toughness of the weld. be. (Example) Next, an example of the present invention will be described. Examples (1) to (4) After extruding an ingot with a diameter of 9" having the chemical composition shown in Table 1 into a rod with a diameter of 9 mm, annealing and wire drawing were repeated several times to obtain a rod with a diameter of 1.6 mm. Filler metal [(1) to (4)],
Comparative example filler metals [(1) to (2)] and conventional A4043 filler metal and A5356 filler metal were obtained.

[Table] This filler metal was used to weld a welding base material (A6NO1P-T5 material) with the chemical composition shown in Table 2.

[Table] Toughness (Sharpey impact value), mechanical performance (tensile strength, yield strength, elongation) and color tone test between the base metal and the weld were conducted on the weld thus obtained. The results are shown in Table 3. Mechanical performance and toughness were determined by welding a 5 mm thick base metal with the composition shown in Table 2 by the welding method and welding conditions shown below, and after leaving it at room temperature for one month after welding. After removing the parts, a Charpy impact test and a tensile test were conducted. Welding method Fully automatic MIG, downward position welding conditions Current: 200A Voltage: 19V Speed: 60cm/min Ar flow rate: 25/min Also, the color tone test between the base metal and the welded part was performed on the welded joint plate of the above welded plate. The surface was machined to 1 mm along with the extra layer, and after being immersed in a 5% oxalic acid aqueous solution for one week to perform an accelerated corrosion test, the cut surface was observed with the naked eye under natural light.

【table】

[Table] As is clear from Table 3, welding using the filler metal of the alloy of the present invention [Examples (1) to (4)]
It has superior toughness to those welded using A4043, and almost the same toughness and mechanical properties as those welded using A5356, and there is no difference in color tone between the weld and the base metal, making it more durable than conventional welds. It can be seen that this method is superior to that using filler metal. (Effects of the Invention) As detailed above, the filler metal of the present invention has excellent toughness and corrosion resistance in welding the base metal of an Al-Mg-Si aluminum alloy for drawing, so it adheres well to the base metal. Since it is difficult to cause differences in color tone between parts, it is extremely useful industrially, as it can improve the efficiency of maintenance work and reduce the weight of structures to be welded.

Claims (1)

[Claims] 1 Filler metal for welding Al-Si-Mg alloy for drawing, containing 1.0 to 5.0 wt% Si, 0.5 to 3.0 wt% Mn, and 0.01 Ti.
~0.3wt%, B0.0001~0.01wt% are essential components,
An aluminum alloy filler material containing one or both of 0.01 to 0.2 wt% of Cr and 0.05 to 0.3 wt% of Zr, with the remainder being Al.