®COPYRIGHT
2000 THE ESAB GROUP, INC. LESSON
VI 6.1.0.7
Although carbon steel, low alloy steels,
stainless steels, magnesium, copper, copper alloys,
titanium and other metals may be welded by one or all of the processes described
above, this Lesson will be confined
to the filler metals for welding mild or carbon steels, and
low alloy high strength steels with
the GMAW and GTAW processes. 6.2 MANUFACTURING
6.2.0.1
The manufacture of solid welding wires
for GMAW or GTAW differs from the manu- facture
of coated or flux cored electrodes in that the deoxidizers and alloying elements
that contribute
to the purity and mechanical properties of the weld metal, must be included in
the wire chemistry
rather than in the flux. Therefore, the raw material must be ordered from the
supplier to exact specifications. When
received, a sample from both ends of each coil of the hot
rolled rod is analyzed by the manufacturer to ensure that the “hot rod”,
as it is called, meets these
specifications. 6.2.0.2
The hot rod is cleaned to remove mill
scale or rust and drawn to an intermediate diameter.
At this stage, the wire has “work hardened” which necessitates
that it be annealed before
it is copper plated, drawn down to final size, spooled and packaged.
6.2.0.3 Close
quality checks must be made throughout the manufacturing process to insure
that the end product is a smooth finished,
uniform diameter wire, that will feed easily through the
end user’s wire feeding equipment and welding gun. The wire is copper
plated and/or otherwise
coated to retard oxidation or rusting of the wire, to decrease contact tip wear,
and to assure
good electrical conductivity. The plating or coating must not flake off
or leave a residue that
will clog the wire feed cable or the welding gun. If copper coated, the
layer of copper must be
kept to a low level to minimize copper welding fumes and flaking.
