Certification Examination Practice

Illinois Structural Welding Technician Certification Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of preheating steel before welding?

a) To clean the surface

b) To increase welding speed

c) To reduce the risk of cracking

d) To improve appearance

Rationale: Preheating reduces thermal gradients and minimizes the

risk of weld and heat-affected zone cracking.

• Which welding process uses a consumable electrode coated with flux?

a) TIG

b) MIG 1 / 4

c) Shielded Metal Arc Welding (SMAW)

d) Plasma Arc Welding

Rationale: SMAW employs a consumable electrode coated with flux

that generates shielding gas and slag.

• What type of current is commonly used for SMAW on mild steel?

a) AC

b) DC Electrode Negative

c) DC Electrode Positive

d) None of the above

Rationale: DC Electrode Positive (DCEP) provides deeper penetration

for mild steel in SMAW.

• Which welding position is referred to as “1G”?

a) Vertical flat groove

b) Flat position

c) Horizontal position

d) Overhead position

Rationale: 1G indicates a flat groove weld where the welding is

performed on a horizontal surface.

• What is the main purpose of a welding procedure specification (WPS)?

a) To list required tools

b) To identify welders

c) To provide detailed welding instructions ensuring quality

d) To determine paint type 2 / 4

Rationale: A WPS outlines essential variables such as amperage,

voltage, and technique to maintain consistent weld quality.

• Which defect is characterized by a long, narrow separation along the

weld metal?

a) Porosity

b) Undercut

c) Cracks

d) Slag inclusion

Rationale: Cracks are long, narrow separations that can occur due to

stress, cooling rates, or improper welding technique.

• What is the recommended shielding gas for MIG welding carbon steel?

a) Helium

b) Carbon dioxide only

c) Argon-CO2 mixture

d) Oxygen

Rationale: An Argon-CO2 mixture provides stable arc, good

penetration, and minimal spatter for carbon steel MIG welding.

• Which welding process is best suited for thin sheet metal?

a) SMAW

b) Submerged Arc Welding

c) Gas Tungsten Arc Welding (GTAW/TIG)

d) Flux-Cored Arc Welding 3 / 4

Rationale: GTAW/TIG provides precise heat control and minimal

distortion, ideal for thin metals.

• What does “FCAW” stand for?

a) Flux-Coated Arc Welding

b) Flux-Conduction Arc Welding

c) Flux-Cored Arc Welding

d) Fully Coated Arc Welding

Rationale: FCAW uses a tubular wire with flux core, allowing welding

with or without shielding gas.

• What is the purpose of post-weld heat treatment (PWHT)?

a) Increase weld speed

b) Improve weld appearance

c) Relieve residual stresses and reduce hardness

d) Remove slag

Rationale: PWHT reduces residual stress, decreases brittleness, and

prevents cracking in high-strength steels.

• Which welding defect is caused by improper cleaning between

passes?

a) Porosity

b) Cracks

c) Slag inclusion

d) Burn-through

• / 4