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Gas Tungsten Arc Welding Handbook
4. Hold the welding rod as shown in Figure 8-13 and
move it so the end is approximately 1″ (25.4 mm)
from the electrode.
5. Start the arc at low current. Lower the torch so the
electrode tip is approximately 1/16″ (1.6 mm) from
the surface.
6. Increase the amperage and form a weld pool
approximately 1/4″ (6.5 mm) in diameter.
7. Bring the rod into the front edge of the pool and
melt enough rod to form a slight crown on the
surface.
8. Draw the rod approximately 1/2″ (12.7 mm) away
from the pool.
9. Move the torch forward approximately 3/16″
(4.8 mm) and add rod again as in Step 7.
10. Continue moving the arc across the joint, adding
rod as before.
11. Stop the weld at the end of the plate. Remember to
hold the torch at the end until the weld cools. This
protects the weld with shielding gas as it cools.
Problem Areas and Corrections:
1. Uneven top weld width and low crown.
Possible cause: Variation in travel speed.
Solution: Maintain a consistent travel speed.
Possible cause: Heat buildup in the weld pool.
Solution: Increase the travel speed as the plates
get hotter.
Possible cause: Variation in adding rod.
Solution: Add rod to form a consistent crown.
2. Undercut.
Possible cause: Torch not aligned vertically.
Solution: Maintain a 90° work angle.
Possible cause: Not enough fi ller metal added to
the weld pool.
Solution: Add rod to the center of the weld pool.
3. Penetration uneven or lack of penetration.
Possible cause: Inconsistent travel speed.
Solution: Maintain a consistent travel speed.
Possible cause: Inconsistent rod addition.
Solution: Add fi ller metal to create a consistent
crown on the weld pool.
Possible cause: Insuffi cient amperage.
Solution: Increase amperage and add more
welding rod.
Possible cause: Inconsistent torch height.
Solution: Hold the torch at a consistent height.
Welding Procedure Number 8-3
Weld joint type: Square-groove butt
Position: Flat
Material type: Cold-rolled steel
Thickness: 1/16″ (1.6 mm)
Filler metal: ER70S-2 or 6
Diameter: .045″–.062″ (1.1 mm – 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. Tack weld the plates together.
3. Raise the part to be welded 1/8″ (3.2 mm) above
the table with metal blocks.
4. Align the torch to the angles shown in Figure 8-14
and lower the torch until the electrode tip is
approximately 1/8″ (3.2 mm) from the surface.
5. Position the end of the welding rod approximately
1″ (25.4 mm) from the electrode.
Figure 8-14.
Torch position for a square-groove butt weld
in the fl at position. (Mark Prosser)