Customer enquiryabout ER 4043 andER4047

A customer who often use ER4043aluminum welding wire for welding 6061 and casting asked us: someone suggested to him that ER4047 should be used as filling welding material, because it has better welding effect.But we know that ER4047 is more expensive than ER4043. Is it necessary to adjust under this circumstance?

First, let’s first understand that ER4043 and ER 5356 are the most common aluminum-filled alloys welding wire, which account for 80% of all aluminum welding wire sales. Therefore, one of the two is the right choice for most aluminum welding applications.

We generally think that the ER4043 should be selected for welding 6XXX alloys and most casting alloys.

The ER5356 is the right choice when welding most 5XXX alloys or welding 5XXX alloys to 6XXX alloys.

The ER5356 is also ideal for welding most 6XXX alloys.

The difference between ER4043 and ER4047: 4043 is aluminum with 5% silicon added; and 4047 is aluminum with 12% silicon added.

What is the role of silicon added to the alloy?

Pure metals have a specific melting point. However, the alloy melts over a range of temperatures.
When heated, melting begins at a certain temperature, it name is  solidus line, and the melting with a higher temperature, is a liquidus. The temperature difference between the liquidus and the solidus is  the melting range.

The resistance of the weld crack  related to the melting range. The smaller the melting range, the stronger the crack resistance of the alloy. The alloy composition of ER4047 determines its lower melting range.
Therefore, ER4047 has three advantages over ER4043.
1.ER4047 has a lower melting point
2.ER4047 has higher strength
3.ER4047 has better mobility

Of course, ER4047 also has disadvantages.
1.Difference in ductility:
The ductility of 4043 is approximately 7% to 8%; and the ductility of 4047 is small, approximately 2% to 4%. Although most structural designs do not consider ductility. However, some workpiece structures are prone to plastic deformation during their lifetime. For example, cars sometimes crash during testing and use. Therefore, when welding the structure of the car, the 4043 will be more than 4047 because it has better ductility.
2.More expensive than ER4043:
Due to its lower elongation, ER4047 requires more intermediate annealing thanER 4043 during processing, so the price is higher.

Now, let’s go back to the customer consultation question: Should we abandon all the ER4043 adjust to ER4047? It’s unnecessary.

The ER4047 is not powful. You can use ER4043 exactly as you would most industry standards. But if you encounter a hot crack problem with ER 4043, you can try ER4047.