Arc welding of aluminum: choice of welding alloy
Selection welding alloy for welding aluminum
Corporation of Japan KOBE STEEL in your manual arc welding of aluminum and aluminum alloys provides advice on selecting the appropriate welding alloy of those, which are presented in the Japanese standard JIS Z 3232 (table). Numerals alloys match those of ISO and EN.
The following factors are taken into account:
- tendency to crack formation;
- tensile strength of the seam;
- plastic properties of the alloy;
- corrosion resistance;
- a combination of colors and shades of the weld base metal after anodizing.
Among all the welding materials, most commonly used aluminum alloys 4043 and 5356. Below are the main points, to which you should pay attention when choosing a welding material.
Aluminum Alloy Welding 4043
Alloy 4043 exhibits high resistance to hot cracking and therefore well suited for welding 6xxx series alloys, as well as aluminum castings. Its disadvantages: 1) the seam material has low ductility and 2) due to the high silicon content, its color after anodizing does not match well with the color of the 5XXX and 6XXX series alloys. Moreover, alloy 4043 not suitable for welding alloys of the 5XXX series with a high magnesium content (3 % and more), since in this case a too much Mg intermetallic particles in the weld metal2Si, which reduces the ductility and increases the tendency to form cracks.
Aluminum Alloy Welding 5356
Alloy 5356 widely used for welding alloys of the 5XXX series (for example, popular alloy 5083) and alloys of the 6XXX series (for example, 6061). Consumption of this alloy is more than half of the total global consumption of aluminum welding alloys. Alloy 5356 It contains a small amount of titanium, to provide a fine microstructure, and thereby improve the mechanical properties of the weld metal. If need good match colors and weld base metal, for example, decorative or construction products, apply welding alloy 5356.
Aluminum Alloy Welding 2319
In most designs of welded joints in aluminum and aluminum alloys the weld metal is not thermally hardenable alloy or a thermally hardened only slightly due to the formation of the solid solution alloying elements in the base metal. therefore, when weldments of thermally hardenable alloys after welding must be heat treated, selection of welding material is very limited. When welding alloys 2219 and 2014 thermally hardenable welding alloy 2319 It provides maximum strength weld.
Aluminum alloys welding 5183, 5356, 5556 and 5654
welding alloys 5183, 5356, 5556 and 5654, that have a nominal magnesium content more 3 %, are not suitable for products and designs, which operate at temperatures above the 65 ° C, since they can be susceptible to stress cracking. welding alloy 5554 and all other alloys, shown in the above table except, suited for operation at elevated temperatures.
Aluminum alloys welding 4043 and 4047
Aluminum-magnesium alloys welding have high resistance to general corrosion, when used in welding of aluminum alloys with magnesium content close. However, welding 5xxx series alloys may be anodic aluminum alloys 1xxx series, 3XXX and 6xxx. Therefore, when working in water or in a humid environment weld metal itself will corrode and protect the base metal from corrosion. This will occur at different rates depending on the difference of the electric potentials of the weld metal and the base metal. In this case, welding of aluminum-silicon alloys, such as alloys 4043 and 4047, It is more preferred from the viewpoint of corrosion resistance, than an alloy 5356 welding, for example, structure of the alloy 6061. That's why, apparently, welding alloy 4043 used for welding bicycle frames made of aluminum alloy 6061.
Source:
The Arc Welding of Nonferrous Metals, KOBE STEEL, LTD, 2011
