Linde BOC RAPTOR Operating Manual page 42

Welding Progression Angle
Weld Metal
Slag
Direction of Welding
Double 'U' Butt Weld
Horizontal Butt Weld
General notes on Butt Welds
The first run in a prepared butt weld should be
deposited with an electrode not larger than
WELD BEADS
42
Electrode
Arc
Weld Pool
Workpiece
Used on thick plates an alternative to a single 'V' preparation. It has advantages
as regards speed of welding. It takes less weld metal than a single 'V', there is less
contraction and therefore a lessened tendency to distortion. Preparation is more
expensive
than in the case of a 'V', as machining is required. The type of joint is most suitable
for material over 40 mm in thickness.
For use on thick plate that is accessible for welding from both sides. For a given
thickness it is faster, needs less weld metal and causes less distortion than a single
'U' preparation.
The lower member in this case is bevelled to approximately 15° and the upper
member 45°, making an included angle of 60°. This preparation provides a ledge on
the lower member, which tends to retain the molten metal.
ELECTRODE
70–85˚
4.0 mm. The angle of the electrode for the various
runs in a butt weld is shown.
70˚ - 85˚