SAW Metallurgy & Weld Quality Inspection 2

Question 1

What is the primary cause of hydrogen-induced cracking (HIC) in SAW welds?

Accepted Answer

Diffusible hydrogen from moisture in flux

Answer

Moisture absorbed in SAW flux decomposes in the arc and introduces diffusible hydrogen into the weld metal, which can cause HIC in susceptible microstructures.

Question 2

Which non-destructive testing method is most effective for detecting subsurface lack-of-fusion defects in a SAW weld?

Accepted Answer

Ultrasonic testing

Answer

Ultrasonic testing can detect internal volumetric and planar defects such as lack of fusion that are inaccessible to surface methods.

Question 3

In the heat-affected zone (HAZ), the region immediately adjacent to the fusion line is called:

Accepted Answer

Coarse-grained HAZ

Answer

The coarse-grained HAZ (CGHAZ) is closest to the fusion line, where peak temperatures cause significant austenite grain growth.

Question 4

A SAW weld bead shows excessive convexity. What is the most likely consequence?

Accepted Answer

Stress concentration at the weld toes

Answer

Excessive convexity creates a sharp angle at the weld toes, acting as a stress riser that reduces fatigue resistance.

Question 5

Carbon equivalent (CE) formulas are used to predict:

Accepted Answer

Susceptibility of steel to hydrogen cracking

Answer

Carbon equivalent quantifies a steel's hardenability and its tendency to form brittle martensite, indicating risk of hydrogen-induced cracking.

(SAW) Submerged Arc Welding Certification Practice Test

(SAW) Submerged Arc Welding Certification Practice Test

SAW Metallurgy & Weld Quality Inspection 2