Welding of Aluminium and its Alloys
Posted: 25 Sep 2010, 08:36
Aluminium and its alloys are mainly used for their low weight / density and and good corrosion resistance even at low temperature. Welding aluminium is a lot more critical as compared to steels.
Here I am sharing some of the information I have on the subject.
As per ASTM numbering system, aluminium can be divided in eight groups based on alloying elements.
Al Alloy - Alloying element - Weldability
1xxx - No major alloying element - Good
2xxx - Cu - Bad
3xxx - Mn - Good
4xxx - Si - Good
5xxx - Mg - Good
6xxx - Mg & Si - Bad
7xxx - Zn - Bad
8xxx - Sn - Bad
Most suited welding processes:
GTAW
GMAW
PAW
Welding consumables:
1xxx - Consumables to be used may contain Zr, Ti or B for gain refinement. As per AWS 5.10, you may use ER1100 or ER1188
2xxx - As per AWS 5.10, you may use ER2319
3xxx - Any consumable with alloying equivalent to 4xxx or 5xxx. You may use ER4xxx or ER5xxx as per AWS 5.10
4xxx & 5xxx - Refer to AWS 5.10 for the matching composition or higher
Typical Welding Procedure:
Preheat: 50 deg C min.
Interpass: below 250 deg C
Avoid weaving due to high heat input, cracking
Look for more in API 582
Typical Welding Problems:
Aluminium and its alloys are difficult to weld due to the oxide layer which causes poor fusion and porosity problems.
To get a quality weld with GTAW, use AC to remove the oxide layer.
With GMAW either AC or DC may be used. With DC, keep the filler wire positive.
Here I am sharing some of the information I have on the subject.
As per ASTM numbering system, aluminium can be divided in eight groups based on alloying elements.
Al Alloy - Alloying element - Weldability
1xxx - No major alloying element - Good
2xxx - Cu - Bad
3xxx - Mn - Good
4xxx - Si - Good
5xxx - Mg - Good
6xxx - Mg & Si - Bad
7xxx - Zn - Bad
8xxx - Sn - Bad
Most suited welding processes:
GTAW
GMAW
PAW
Welding consumables:
1xxx - Consumables to be used may contain Zr, Ti or B for gain refinement. As per AWS 5.10, you may use ER1100 or ER1188
2xxx - As per AWS 5.10, you may use ER2319
3xxx - Any consumable with alloying equivalent to 4xxx or 5xxx. You may use ER4xxx or ER5xxx as per AWS 5.10
4xxx & 5xxx - Refer to AWS 5.10 for the matching composition or higher
Typical Welding Procedure:
Preheat: 50 deg C min.
Interpass: below 250 deg C
Avoid weaving due to high heat input, cracking
Look for more in API 582
Typical Welding Problems:
Aluminium and its alloys are difficult to weld due to the oxide layer which causes poor fusion and porosity problems.
To get a quality weld with GTAW, use AC to remove the oxide layer.
With GMAW either AC or DC may be used. With DC, keep the filler wire positive.