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Mechanical properties are of primary
importance for many critical service applications such as pressure
vessels and low temperature service
applications. For these welds, a compromise in performance features
may be necessary to fulfill the required
mechanical properties.
The main factor governing the choice
of the welding wire is its influence on the composition and mechanical
properties of the weld.
Chemical and mechanical properties
of a submerged arc weld are determined mainly by four factors: the
composition of the base metal, the
composition of the wire used, the specific flux employed, and the welding
conditions.
Composition of the base metal is most
important in 1 through 4 or 5 pass submerged arc welds, since the
ratio of fused base metal to added
filler metal may be as high as 2 to 1. In most other fusion welding
processes, multiple pass weld bead
procedures must be employed, minimizing the influence of base plate
chemistry.
SUBMERGED ARC FLUXES
are selected for many jobs for their performance features,
i.e., peeling, rust
handling ability, current carrying
capacity, multi-wire capability, and good AC operability. For some critical
service applications and most multi-pass
welds in plate thicknesses exceeding 1 inch (25 mm), weld
mechanical properties are most important
and fluxes from a select group MUST BE USED.
SUBMERGED ARC WIRES
are selected for their influence on the mechanical
properties and/or the
required weld metal composition.
Fluxes for Submerged
Arc Welding
Submerged arc welding fluxes are granular,
fusible mineral compounds which blanket the arc and provide
shielding, cleansing, and bead shape
control. They greatly influence process usability and weld metal
mechanical properties. Many different
fluxes are available, each offering unique performance features
allowing process optimization for
different application requirements.
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