Page 163 - Welding of Aluminium and its Alloys

146 The welding of aluminium and its alloys

Welding can be carried out with equal ease with the plate in the
horizontal, vertical or overhead position although in other than the flat
position the welding time needs to be reduced from that listed in Table 7.7.
This may result, however, in an increased level of porosity. Other defects
include cracking, lack of fusion and burn-through. To prevent and control
burn-through a temporary backing bar may be used. Fit up is important and
for the highest strength the gap between the plates should be as small as
possible.