How to choose aluminum welding wire

Attention should be paid to the selection of aluminum welding wire:

1) Crack sensitivity of welded joints
 The direct factor affecting crack sensitivity is the matching of base metal and welding wire. Selecting the weld metal whose melting temperature is lower than that of the base metal can reduce the crack sensitivity of the weld metal and the heat-affected zone. For example, when welding 6061 alloy with 0.6% silicon content, the same alloy is used as the weld, and the crack sensitivity is very high.

However, ER4043 welding wire with 5% silicon content has a lower melting temperature than 6061 alloy and has higher plasticity during cooling, so it has good crack resistance. In addition, the weld metal avoids the combination of magnesium and copper, because Al-Mg-Cu has a high crack sensitivity.

2) Mechanical properties of welded joints
Industrial pure aluminum has the lowest strength, 4000 series aluminum alloys are in the middle, and 5000 series aluminum alloys have the highest strength. Although aluminum-silicon welding wire has high crack resistance, silicon-containing welding wire has poor plasticity. Therefore, for joints that require plastic deformation after welding, silicon-containing welding wire should be avoided.

3) The performance of the welded joint
The choice of filler metal is not only dependent on the composition of the base material, but also related to the geometry of the joint, the requirements for corrosion resistance during operation, and the appearance requirements of the welded parts. For example, in order to make the container have good corrosion resistance or prevent contamination of the stored products, the welded container for storing hydrogen peroxide requires high-purity aluminum alloy. In this case, the purity of the filler metal must be at least equivalent to that of the base material.

Generally speaking, ER4043 and ER5356 are the most widely used aluminum alloy welding wires in aluminum alloy welding. We can choose a more suitable welding wire according to the application requirements after welding.