MetFab - Air Products Welder's Handbook - Flipbook - Page 26
Welding of sheet metal
Both TIG and MIG/MAG processes can
be used to weld sheet material - this is
typically regarded as material which is
3mm or less. When MIG/MAG welding
you should only use dip or pulse transfer
techniques.
The most common joint types are:
‘T’ joint
The edges of the sheet to be welded should
be:
• cut square
• free of burrs
• clean and degreased
• free of oxides
When welding sheet material, always
ensure a close fit-up of the joint. Sheets
should be held in alignment by clamping
to a backing bar. If this is not possible, place
small tack welds every 50mm along the
joint line. When welding butt joints and a
full penetration weld is required, set a gap
equal to 50% of the plate thickness prior to
clamping or tack welding.
Butt joint
Gap not greater than
half sheet thickness
Corner joint
No gap
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