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

Higher arc voltage lengthens the arc column, spreading heat laterally to produce a wider, flatter bead with reduced depth of fusion into the base metal.

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

Weld metal toughness on high-strength steels depends on controlled carbon equivalent and appropriate alloy additions; the wire chemistry must be matched to the required mechanical properties.

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

Tandem SAW optimizes each wire independently: the lead wire uses DCEP for deep penetration to achieve fusion, while the trail wire uses DCEN or AC to maximize deposition rate and shape the bead.

Question 4

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

Accepted Answer

Lower penetration and higher deposition rate

Answer

With DCEN, more heat is generated at the electrode tip rather than the base metal, melting more wire per unit time (higher deposition) while reducing fusion depth (lower penetration).

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

In AWS A5.17, 'F7' designates a flux that, when used with the specified wire, produces weld metal with a minimum 70,000 psi tensile strength; the number represents tensile strength in multiples of 10,000 psi.

(SAW) Submerged Arc Welding Certification Practice Test

(SAW) Submerged Arc Welding Certification Practice Test

SAW Flux Types & Wire Selection 2