Welding Aluminium Defects. The two that are most notorious are Hot and Cold cracking. Heat generated for joining can cause significant changes in material microstructure thereby compromis-ing the mechanical property of the base metal and caus-.
Some of the most common weld defects are porosity lack of fusion and burn through with aluminum presenting a few more welding challenges than steel. Welding defects may occur either outside or inside the weld metal. Insufficient welding current Excessive travel speed Inadequate joint preparation Inadequate back gouge Excessive arc length Incomplete Joint Penetration Incomplete Joint Penetration A joint root condition in a groove weld in which weld metal does not extend through the joint thickness.
Hydrogen can come from many sources such as moisture in electrode fluxes humid air damp weld joints and more.
Hydrogen becomes present from either water vapor or hydrocarbon contamination through oils greases lubricants and solvents. The former happens because of shrinkage that takes place as the metal solidifies after welding. Defects may originate in the substrate metal as a result of the thermo-mechanical fabrication process used to produce the sheet or extrusion or during handling and storage of the material before finishing. Aluminum is one of the metals most susceptible to porosity.