10
Multipass
Welding
Multipass
welding will generally be necessary for welding material over 1/8-inch thick.
The number of passes
required
will depend on the thickness of the material, and on the current carrying capacity
of the equipment
involved
and the assembly being fabricated. The first pass should be a ”root-weld”
and provide complete
fusion
at the bottom of the joint. Subsequent passes can be
made at higher currents due to the back-up
effect
of the root weld. Care should be taken to prevent inclusions between weld layers.
On heavy work, it is
sometimes
advantageous to carry all the beads along simultaneously in a staggered arrangement
to utilize
the
residual heat of preceding passes.
