APPLICATIONS & WELDING
Whether it is wrought or foundry alloys, aluminum alloys share the presence of a layer of oxide called alumina, which is said to be refractory. This characteristic makes it impossible to weld without a prior pickling (chemical, electronic or mechanical) of that oxide.
Inherent problems when welding aluminum and its alloys :
- Porosities (due to undissolved hydrogen coming from the base metal, protecting gases or even the electrode's coating).
- Hot cracking (related to the type of base metal welded).
- Reduction of the joints resistance (importance of the selection of right filler metal).
The choice of the filler metal is crucial because it will have influence on : the fluidity, the sensibility to hot cracking, mechanical resistance, joint ductility, corrosion resistance, maintaining service temperature or even the esthetic aspect of the joint.
