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Gas Tungsten Arc Welding Handbook
Welding Procedure
Specifi cations (WPS)
The following eleven procedures have been devel-
oped for GTAW practice and production. Any scrap
material can be used for practice. The weld joint should
fi t properly for good results. Clean all of the materials, as
previously discussed, before tack welding and welding.
When steel is being welded, a small white dot
may form on the weld pool surface. This is a normal
condition and does not require any corrective action.
The material in the dot is silicon, which separates from
the base material and the welding rod. It fl oats on the
surface because it is lighter than the metal.
Gas nozzle sizes are not specifi ed, since many
variables are involved. Always use the largest possible
size. However, do not use a size that will obstruct your
view of the weld pool.
Tooling can be used when welding practice plates.
Tools assist in holding the material in the proper plane and
prevent warpage and misalignment during the welding
sequence. The tooling may also have a gas manifold to
permit use of a backing gas, if desired. See Figure 8-11.
Welding Procedure Number 8-1
Weld joint type: Flat plate autogenous weld
Position: Flat
Material type: Cold-rolled steel
Thickness: 1/16″ (1.6 mm)
Machine setup: DCEN high-frequency start
Shielding gas: Argon
CFH: 15–25
Tungsten type: 1%, 1.5%, or 2% lanthanated,
ceriated, or thoriated
Diameter: 1/16″ (1.6 mm) (tapered)
Procedure:
1. Prepare and clean the materials.
2. Raise the part to be welded 1/8″ (3.2 mm) above
the table with metal blocks.
3. Align the torch to the angles shown in Figure 8-12
(90° work angle and 15°–25° travel angle) and lower
the torch until the tip of the electrode is approximately
1/8″ (3.2 mm) from the top surface.
4. Start the arc at low current; lower the torch until the
electrode tip is approximately 1/16″ (1.6 mm) from
the surface.
A
B
Figure 8-11.
Tooling can support the weld and provide backing gas. A—Hand-built copper backing plates for providing
cover gas to the back side of a butt weld. The weld is positioned on top of the plate and welded. B—This fi xture includes a
manifold for backing gas. The weldment is clamped and held in place by the top bars. (Mark Prosser)