140
Gas Tungsten Arc Welding Handbook
10. Move the torch forward approximately 3/32″
(2.4 mm) and add welding rod again as in Step 8.
11. Continue moving the arc across the joint, adding
welding rod as before.
A. Maintain the proper torch angles.
B. Maintain the proper fi ller rod angles.
12. Stop the weld at the end of the plate. Remember to
hold the torch at the end until the weld cools.
Problem Areas and Corrections:
1. Undercut at top of weld crown.
Possible cause: Torch angle fl at.
Solution: Maintain the proper torch angles.
Possible cause: Not enough fi ller metal added to
the weld pool.
Solution: Add welding rod to the top of the weld
pool.
2. Crown sags.
Possible cause: Gravity.
Solution: Add welding rod to the top of the weld
pool.
Solution: Do not add welding rod in large
amounts.
Solution: Move the torch with a slight circular
motion to hold pool in position.
3. Penetration is uneven on the centerline of the weld.
Possible cause: Torch not centered on the joint.
Solution: Keep the electrode centered on the joint.
Welding Procedure Number 8-5
Weld joint type: Square-groove butt
Position: Vertical uphill
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. Align the parts to be welded with the joint in the
vertical position.
4. Align the torch to the angles shown in Figure 8-16
and move the torch toward the joint until the tip of
the electrode is approximately 1/8″ (3.2 mm) from
the surface.
5. Hold the welding rod so the end is approximately
1″ (25.4 mm) from the electrode.
6. Start the arc at low current. Move the torch
toward the joint until the tip of the electrode is
approximately 1/16″ (1.6 mm) from the surface.
7. Increase the amperage to form a weld pool
approximately 3/16″ (4.8 mm) in diameter.
8. Bring the welding rod into the upper part of the
pool and melt enough fi ller metal to form a slight
crown on the surface.
9. Draw the welding rod approximately 1/2″
(12.7 mm) away from the weld pool.
10. Move the torch upward approximately 3/32″
(2.4 mm) and add welding rod again as in Step 8.
11. Continue moving upward, adding welding rod as
before.
12. Stop the weld at the end of the plate. Remember to
hold the torch at the end until the metal cools.
Figure 8-16.
Torch and welding rod positions for a
square-groove butt weld in the vertical position.
(Mark Prosser)