23 Edge
Preparation by Beveling or Grooving a.
Effect of Edge Bevel or Groove The
effect of edge beveling or grooving is to control the amount of weld reinforcement
(see Fig. 10). The amount
of weld penetration is also affected by changes in bevel depth and volume. For
butt, fillet and multipass
welds, the maximum weld width should be at least somewhat wider than the weld
depth. A ratio of 1.25
to 1.5 weld width/weld depth is preferred to reduce the possibility of center
weld cracking. Proper joint bevels
and proper welding parameter selection assist in obtaining this relationship.
b. When to Bevel or Groove
Beveling or grooving is especially desirable
for butt joints thicker than 5/8 in. Beveling is sometimes used for
material as thin as 1/4 in. where it
can assist in tracking the weld seam with knife edged wheel followers. In
positioned tee joint or comer joint
fillet welding where complete root penetration is desired, the abutting
member is generally bevelled if the
depth of fusion desired for each weld exceeds 3/8-in. c.
Effect of Root Face Dimension The
unbeveled root face should be thick enough for the weld to fuse down into but
not through the butted root
faces, or “nose” of the joint. If the thickness of the nose is inadequate,
there will not be enough metal mass
to absorb the heat of the molten metal and it may spill out of the bottom of the
joint. See Fig. 11. d.
Methods of Edge Preparation 1.
Flame or Plasmarc Cutting - may be done manually or with flame planers or cutting
machines. Refer to your
ESAB Representative for a description of plate edge preparation techniques and
equipment supplied by
ESAB. All loose scale and slag resulting from cutting must be removed before assembly
and welding. It is
not necessary to remove the oxide film formed on cooling; in fact, it is good
practice to allow this oxide film
to remain on the edges if the plates are to be stored for some time before welding
since it will assist in preventing
rusting.
