Ohio Welding Certification Exam MIG

Ohio Welding Certification Exam – MIG Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2025|2026 Q&A | Instant Download Pdf

• What is the primary shielding gas used for MIG welding mild steel?
• Helium
• Oxygen
• Argon/CO₂ mix
• Nitrogen

Rationale: An argon/CO₂ blend provides proper arc stability,

penetration, and minimal spatter for mild steel MIG welding.

• What type of current is used for MIG welding?
• AC
• DC Electrode Positive (DCEP)
• DC Electrode Negative (DCEN)
• Pulsed AC 1 / 4

Rationale: MIG welding uses DCEP (electrode positive) to achieve

proper penetration and stable arc characteristics.

• Which joint design is most commonly used for plate welding?
• Lap joint
• Butt joint
• Tee joint
• Corner joint

Rationale: Butt joints are commonly used to join plates edge-to-

edge, providing full penetration and strength.

• What is the ideal electrode extension for MIG welding?
• 1 inch
• 3 inches
• 3/4 inch
• 1/4 inch

Rationale: A 3/4-inch electrode extension provides a stable arc and

proper shielding gas coverage.

• How does increasing wire feed speed affect MIG welding?
• Decreases penetration
• Increases spatter
• Increases deposition rate
• Reduces arc stability

Rationale: Higher wire feed speed increases the amount of filler

metal deposited per unit time. 2 / 4

• What is the main function of shielding gas in MIG welding?
• Cooling the weld
• Protecting molten metal from atmospheric contamination
• Increasing current
• Reducing electrode wear

Rationale: Shielding gas prevents oxidation and contamination of the

molten weld pool.

• Which welding position is considered flat in MIG welding?
• 1G
• 2G
• 3G
• 4G

Rationale: 1G indicates a flat position weld, where gravity assists in

puddle formation.

• What is the recommended travel angle for MIG welding?

A) 90°

B) 0°

• 10–15° push angle
• 45° pull angle

Rationale: A slight push angle ensures proper penetration and gas

coverage.

• Which metal is most commonly welded with MIG?
• Cast iron 3 / 4

• Titanium
• Mild steel
• Nickel

Rationale: Mild steel is widely used due to its ease of welding and

cost-effectiveness.

• What can cause porosity in a MIG weld?
• Excessive heat
• Low voltage
• Contamination on the base metal or wire
• Incorrect travel speed

Rationale: Oil, rust, or dirt can trap gas, creating porosity in the

weld.

• Which factor primarily determines weld penetration in MIG

welding?

• Electrode type
• Shielding gas
• Voltage and amperage settings
• Travel speed

Rationale: Proper voltage and amperage control the heat input,

affecting penetration depth.

• What is the purpose of a backstep technique in MIG welding?
• Reduce spatter
• Increase speed
• / 4