SAW Flux Types & Wire Selection 2

Question 1

What effect does increasing arc voltage have on SAW weld bead geometry?

Accepted Answer

Increases bead width and decreases penetration

Answer

Increases penetration and decreases bead width

Answer

Decreases both bead width and penetration equally

Answer

Has no effect on bead geometry, only on travel speed

Question 2

When selecting SAW wire for low-alloy high-strength steel, what is the primary consideration for maintaining weld metal toughness?

Accepted Answer

Controlling carbon equivalent and matching alloy additions (Ni, Mo) to base metal requirements

Answer

Maximizing silicon content in the wire for better fluidity

Answer

Using the largest diameter wire available for higher heat input

Answer

Selecting the highest basicity flux regardless of wire chemistry

Question 3

In a tandem SAW setup, what is the typical polarity arrangement for lead and trail electrodes?

Accepted Answer

Lead electrode DCEP for penetration; trail electrode DCEN or AC for deposition

Answer

Both DCEP to maximize penetration on both wires

Answer

Both DCEN to maximize deposition rate

Answer

Both AC at the same phase angle

Question 4

Compared to DCEP (electrode positive), using DCEN (electrode negative) polarity in SAW produces:

Accepted Answer

Lower penetration and higher deposition rate

Answer

Higher penetration and lower deposition rate

Answer

Identical penetration and deposition as DCEP

Answer

Higher heat input to the base metal with equal deposition

Question 5

In the AWS A5.17 flux-wire classification 'F7A2-EM12K', what does the 'F7' prefix indicate about the weld deposit?

Accepted Answer

Minimum tensile strength of 70,000 psi (70 ksi)

Answer

Minimum tensile strength of 60,000 psi (60 ksi)

Answer

Minimum tensile strength of 80,000 psi (80 ksi)

Answer

Minimum tensile strength of 72,000 psi (72 ksi)

Question 6

What does the 'A2' designator in the AWS A5.17 classification 'F7A2-EM12K' specify?

Accepted Answer

As-welded condition with minimum 20 ft-lb CVN impact toughness at −20°F

Answer

Two-pass welding technique is required for qualification

Answer

2% alloy content limit in the wire electrode

Answer

Second revision of the A5.17 standard applies

Question 7

Why is controlling electrode extension (contact-tip-to-work distance) important in SAW welding?

Accepted Answer

Extension affects resistive preheating of the wire, altering deposition rate and arc current

Answer

Longer extension increases flux layer depth automatically

Answer

Extension determines which flux type must be used

Answer

Extension has no measurable effect on SAW weld quality