456A GTAW TIG 2

Question 1

What is a gas lens in a GTAW torch and what advantage does it provide?

Accepted Answer

A fine mesh screen that produces a smooth, laminar gas flow for better shielding coverage, especially at extended stick-out distances and on joints with restricted access

Answer

A gas lens replaces the standard collet body and uses multiple layers of fine stainless steel mesh to convert turbulent gas flow into smooth, laminar flow. This provides more effective shielding coverage, allows longer tungsten stick-out for better visibility and access to tight joints, and reduces gas consumption while improving weld quality.

Question 2

What causes tungsten contamination in a GTAW weld?

Accepted Answer

Dipping the tungsten electrode into the weld pool, which deposits tungsten particles in the weld

Answer

Tungsten contamination occurs when the electrode tip contacts the molten weld pool, depositing tungsten particles in the weld. Tungsten inclusions appear as bright white spots on radiographs and are considered weld defects in critical applications. If contamination occurs, the affected area must be ground out, and the tungsten must be re-prepared.

Question 3

What is the function of a foot pedal (foot amptrol) in GTAW welding?

Accepted Answer

To provide real-time variable amperage control during welding, allowing the welder to increase or decrease heat input while welding

Answer

The foot pedal (amptrol) gives the GTAW welder precise, real-time control over welding current from zero to maximum while welding. This allows the welder to increase heat for thicker sections, reduce heat approaching edges to prevent burn-through, and taper the current down at the end to properly fill the crater.

Question 4

What is the purpose of adding filler metal in GTAW welding?

Accepted Answer

To add material to the weld joint for building up the weld cross-section, filling gaps, and matching the base metal composition and strength

Answer

Filler metal is added separately (by hand-feeding a rod) to provide additional weld metal for filling joints, building up weld reinforcement, bridging gaps, and matching the base metal's composition and mechanical properties. Some GTAW welds on thin material can be made autogenously (without filler) by fusing the base metal edges together.

Question 5

What is a GTAW walking the cup technique used for?

Accepted Answer

Rocking the ceramic gas cup alternately on each side of the joint to maintain consistent travel speed, torch angle, and arc length while welding pipe or tubing

Answer

Walking the cup is a GTAW pipe welding technique where the welder rocks the ceramic gas cup from side to side on the pipe bevel, alternating contact points like walking. This provides consistent torch angle, travel speed, and arc length, producing uniform weave beads — particularly valuable in pipe root and fill passes where consistency is critical.

Red Seal Welder 456A Practice Test

Red Seal Welder 456A Practice Test

456A GTAW TIG 2