 |
|
|
|
|
|
|
|
|
|
 |
 |
 |
 |
 |
 |
 |
 |
|
|
4043 is designed for welding
6xxx series aluminum alloys. It may also be used to weld 3xxx series alloys
or 2xxx alloys. 4043 has a lower melting point and more fluidity than the
5xxx series filler alloys, and is preferred by most welders because it "wets
and flows better" and it's less sensitive to weld cracking with
the 6xxx series base alloys. 4043 can also be used for welding castings. 4043
also makes brighter looking MIG welds with less smut because it doesn't contain
magnesium. 4043 gives more weld penetration than 5356, but produces welds
with less ductility than those made using 5356. However, 4043 is not well
suited for welding Al-Mg alloys and should not be used with high Mg content
alloys such as 5083, 5086 or 5456 because excessive magnesium-silicide (Mg2Si)
can develop in the weld structure to decrease ductility and increase crack
sensitivity. (One exception to this rule is 5052, which has a low magnesium
content.)
5356 wire has become the most commonly used of all aluminum filler alloys
because of its good strength and its good feed-ability when used as a MIG
electrode wire. It is designed to weld 5xxx series structural alloys and 6xxx
series extrusions, basically anything other than castings, because castings
are high in silicon. Its one limitation is that 5356 is not suitable for service
temperatures exceeding 150 degrees Fahrenheit (65 degrees Celsius). The formation
of Al2Mg at elevated temperatures at the grain boundaries makes the alloys
prone to stress corrosion. For components that will be anodized after welding,
5356 is recommended over 4043, which turns jet black when
anodized.
