Figure 7-11 shows that the GROOVE FACE is
that surface of a member that is included in the
groove. The ROOT of a joint is that portion of the
joint where the members approach each other most
closely. The root of a joint may be a point, a line,
or an area when viewed in cross section. A given
joint design may have a ROOT FACE or it may
have a ROOT EDGE. A root face is the surface of
the groove that is adjacent to the root of the joint.
If the root face is of zero width, it is known as a
root edge (fig. 7-11, view C).
Details of joint design involve the size of the
Figure 7-12.--Bevel angle, groove angle, groove radius, and
groove and the space existing between the members
of the joint. Specifications for joint design are
expressed in terms of bevel angle, groove angle,
groove radius, and root opening. Figure 7-12
The GROOVE RADIUS is the radius of the
illustrates the use of these terms.
curved portion of the opening at the bottom of the
groove near the root of the joint. It exists only in
The BEVEL ANGLE is the angle formed
special groove joint designs.
between the prepared edges of a member and a
plane perpendicular to the surface of the member.
The ROOT OPENING refers to the separation
between the members of the joint where the
The GROOVE ANGLE is the included angle of
members are closest together.
the groove between the parts to be joined. For
example, if the edge of each of the two plates to be
The bevel angle, groove angle, and root opening
joined were beveled to an angle of 30°, the groove
of any joint will depend upon the thickness of
angle would be 60°.
material being welded, the kind of joint being made,
and the welding process being employed. As a rule,
oxyacetylene welding requires a larger groove angle
than does manual metal-arc welding. Root opening
is usually governed by the diameter of the filler
material, which in turn depends on the thickness of
the base metal and the position of welding.
Root penetration and joint penetration in
groove welds are illustrated in figure 7-13. ROOT
PENETRATION refers to the depth that a groove
weld extends into the root of the joint. Root
penetration is measured on the center line of the
root cross section. JOINT PENETRATION refers
to the minimum depth that a groove weld extends
from its face into a joint, exclusive of any excess
weld metal that is above the plate surface.
Incidentally, this brings up another term you should
know: REINFORCEMENT OF WELD is the term
used to describe weld metal, on the face of a groove
weld, that is in excess of the metal necessary for the
specified weld size.
As may be seen from figure 7-13, the terms
ROOT PENETRATION and JOINT
Figure 7-11.--Groove face, root face, and root edge.
PENETRATION often refer to the same dimension.
This is the case in views A, C, and E of the