How to make the selection aluminum filler metals
toyota1515 > 07-11-2022, 09:14 AM
The goal when selecting aluminum filler metals is to choose an alloy that produces a weld that best meets the requirements of the product and its intended use. Sometimes the strongest weld is desirable — other times, leak resistance, ductility, corrosion resistance or toughness are more important.
Aluminum GMAW LR
The most common of aluminum filler metals are 4043
and 5356 alloys, both of which are available in wires
for gas metal arc welding (GMAW) or cut-lengths (often
called filler rods) for gas tungsten arc welding (GTAW).
When trying to choose between the common 4043 and 5356 aluminum filler metals, there is a series of five questions to ask to narrow down the selection.
1. What is the aluminum base designation?
2. Will the welded component be exposed to sustained elevated temperature?
3. Will the weldment be subjected to post-weld anodizing?
4. Will shear strength, ductility and toughness be prime considerations?
5. Will post-weld heat treatment be performed?
Providing the base metal is compatible, a 4043 aluminum filler metal will be best for the following:
• Applications that will be subject to long-term elevated temperature exposure (above 150 degrees Fahrenheit).
• Applications where it is necessary to reduce the risk of termination and shrinkage cracking.
• Applications where aesthetics are particularly important, since these filler metals provide bright, clean welds.
• Applications where distortion is of particular concern, as it minimizes this defect.
A 5356 aluminum filler metal would be most appropriate for:
• Welding on 5XXX or 6XXX series of aluminum when tensile strength is most important.
• Achieving good anodized color matching on 5XXX and 6XXX base metals.
• Applications requiring higher ductility and toughness (such as those subject to dynamic loading).
• Applications requiring higher shear strength.
When welding 6XXX series aluminum or 5XXX series aluminum containing less than 3 percent magnesium, it is possible to use either a 4043 or a 5356 filler metal to complete the job. The same holds true for higher shear strength applications; however, it typically takes three fillet passes with a 4043 product to equal the shear strength of one pass using a 5356 filler metal.
Proper storage and handling
Proper storage and handling of aluminum filler metals is essential to ensuring the highest quality welds. It is important to keep the filler metals in a clean, dry area that is of a similar ambient temperature as the weld cell. Moving them from a cold area to a warmer area could cause condensation to form on the surface of filler metals and lead to poor weld quality.
If a spool of aluminum wire isn’t going to be used cover the spool with the plastic bag the wire shipped in or with another protective cover. TIG cut-lengths are best stored in their original box to protect against dirt and debris.