Arc Length & Heat vs. Weld Bead Characteristics

The visual characteristics and mechanical properties of aluminum weldments are controlled by weld bead penetration and shape. A number of variables affect the end properties of the weld bead and they can be controlled by the welder. Presented here is a description of those variables and how they can be used to achieve the desired end results.

Characteristics                      Short Arc                 Long Arc

      Penetration                           Deep                         Shallow
     Weld Width                            Narrow                      Wide
     Weld Height                            High                          Flatter
  Molten Pool Surface               Depressed                    Flat
        Spatter                                 Less                         More
      Arc Noise                           Crackling                   Humming
  Porosity-Surface                        More                         Less

Characteristics                    High Heat                   Low Heat
   Penetration                            Deep                           Shallow
     Surface                               Smooth                        Rippled
      Smut                                   More                            Less
Porosity - Root                          Less                            More

Recommendations
     Root Pass                       Shorter Arc
    Finish Pass                                                          Longer Arc
  5XXX Alloys                     Shorter Arc
                                        Lower Arc Voltage
                                          HigherAmerage
  4XXX Alloys                                                           Longer Arc
                                                                             Higher Arc Voltage
                                                                              Lower Amperage

NOTE: Because 5XXX series alloys conduct heat significantly less than 4XXX series alloys, shorter arc lengths are required for desired penetration.