SAW Metallurgy & Weld Quality Inspection 3

Question 1

What solidification mode produces the most favorable microstructure for corrosion resistance in stainless steel SAW welds?

Accepted Answer

Primary ferrite with austenite transformation

Answer

Primary ferrite solidification (FA mode) results in a weld containing 3–8% delta ferrite, which resists hot cracking and improves corrosion resistance.

Question 2

Lamellar tearing in heavy plate SAW fabrication is most likely caused by:

Accepted Answer

Low-toughness inclusions oriented parallel to the plate surface

Answer

Lamellar tearing occurs when through-thickness shrinkage stresses tear the base metal along elongated manganese sulfide or oxide inclusions lying parallel to the rolled surface.

Question 3

In radiographic testing of SAW welds, porosity appears on the film as:

Accepted Answer

Dark rounded spots

Answer

Porosity appears as dark, rounded spots on radiographic film because gas voids allow more X-ray transmission than surrounding solid metal.

Question 4

The purpose of postweld heat treatment (PWHT) stress relief is primarily to:

Accepted Answer

Reduce residual stresses and temper the HAZ

Answer

PWHT at sub-critical temperatures reduces residual welding stresses and tempers hard microstructures in the HAZ, improving toughness and reducing cracking risk.

Question 5

Which SAW flux type is most prone to moisture pickup and requires the strictest storage and rebaking procedures?

Accepted Answer

Bonded (agglomerated) flux

Answer

Bonded fluxes are manufactured with binders and have higher porosity, making them more susceptible to moisture absorption than fused fluxes.

(SAW) Submerged Arc Welding Certification Practice Test

(SAW) Submerged Arc Welding Certification Practice Test

SAW Metallurgy & Weld Quality Inspection 3