Types Of Joints - Linde BOC RAPTOR Operating Manual

Butt Welding
FACE REINFORCEMENT
ROOT FACE

11.5 Types of Joints

Butt Welds
A butt weld is a weld made between two plates
so as to give continuity of section. Close attention
must be paid to detail in a butt weld to ensure that
the maximum strength of the weld is developed.
Failure to properly prepare the edges may lead
to the production of faulty welds, as correct
manipulation of the electrode is impeded.
Square Butt Weld
The edges are not prepared but are separated slightly to allow fusion through the
full thickness
of the steel. Suitable for plate up to 6 mm in thickness.
Single 'V' Butt Weld
This is commonly used for plate up to 16 mm in thickness and on metal of greater
thickness where access is available from only one side.
Double 'V' Butt Weld
Used on plate of 12 mm and over in thickness when welding can be applied from
both sides. It allows faster welding and greater economy of electrodes than a single
'V' preparation on the same thickness of steel and also has less of a tendency to
distortion as weld contraction can be equalised.
Butt Weld with Backing Material
When square butt welds or single 'V' welds cannot be welded from both sides it is
desirable to use a backing bar to ensure complete fusion.
Single 'U' Butt Weld
WELD FACE
ROOT GAP
WELD BEADS
Two terms relating to the preparation of butt welds
require explanation at this stage. They are:
Root Face: the proportion of the prepared edge
that has not been bevelled.
Root Gap: the separation between root
faces of the parts to be joined.
Various types of butt welds are in common use and
their suitability for different thickness of steel are
described as follows:
41