Instructions / Assembly

56
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GMAW
S
ome stainless steel weld metals during welding have a
t
endency toward hot cracking or tearing when they contain little
or no ferrite — Type 347, for example. When welding these,
more welding passes than indicated in the procedures may be
needed. Stringer bead techniques are also recommended
r
ather than weaving or oscillating from side to side. Hot crack-
ing may be eliminated by stringer bead techniques since there is
a reduction in contraction stresses, hence cooling is more rapid
through the hot short temperature range. A procedure that
t
ends to produce a more convex bead than normal can be very
h
elpful, and care should be taken to fill craters.
W
eld metal hot cracking may be reduced by short-circuiting
transfer welding, because of the lower dilution from the base
metal. Excessive dilution may produce a completely austenitic
weld metal having strong cracking characteristics.
W
hen welding magnetic stainless steels (ferritic and martensitic
t
ypes) to the relatively non-magnetic types (austenitic types), it is
desirable to:
1. Use a single bevel joint to obtain minimum joint
reinforcement.
2. Use low heat input short-circuiting transfer to minimize the
arc deflection encountered when welding magnetic to
non-magnetic steels.
3. For uniform fusion, be sure the wire is kept centered over the
n
on-beveled edge of the joint.
Blue Max
®
Stainless Steel GMAW Electrode