Other Skilled Trades Welding 1 — Questions and Answers
Question 1: What does the acronym MIG stand for in MIG welding?
- Metal Inert Gas (Correct answer)
- Manual Inert Grounding
- Metal Integrated Groove
- Mechanical Induction Gas
Correct answer: Metal Inert Gas
MIG stands for Metal Inert Gas, a welding process that feeds a continuous solid wire electrode through a welding gun shielded by an inert gas.
Question 2: Which welding position is considered the most difficult to perform?
- 1G (Flat)
- 2G (Horizontal)
- 3G (Vertical)
- 4G (Overhead) (Correct answer)
Correct answer: 4G (Overhead)
The 4G overhead position is considered the most challenging because molten metal tends to drip away from the weld pool due to gravity.
Question 3: What shielding gas is most commonly used for MIG welding mild steel in the US?
- 100% Argon
- 100% CO2
- 75% Argon / 25% CO2 (Correct answer)
- 50% Argon / 50% Helium
Correct answer: 75% Argon / 25% CO2
A 75/25 Argon/CO2 mixture (C25) is the most widely used shielding gas for MIG welding mild steel, providing good arc stability and weld appearance.
Question 4: What is the purpose of preheating steel before welding?
- To clean the base metal
- To reduce the risk of cracking and residual stress (Correct answer)
- To increase travel speed
- To eliminate the need for shielding gas
Correct answer: To reduce the risk of cracking and residual stress
Preheating reduces the temperature differential between the weld and base metal, slowing cooling rates and reducing the risk of hydrogen cracking and distortion.
Question 5: In AWS welding certification, what does the 'D1.1' designation refer to?
- Aluminum welding standard
- Structural welding code for steel (Correct answer)
- Pipeline welding standard
- Sheet metal welding code
Correct answer: Structural welding code for steel
AWS D1.1 is the American Welding Society's Structural Welding Code for Steel, the most widely referenced welding standard in US structural fabrication.
Question 6: What type of joint is formed when two pieces of metal are welded end-to-end in the same plane?
- Lap joint
- T-joint
- Corner joint
- Butt joint (Correct answer)
Correct answer: Butt joint
A butt joint is formed when two pieces of metal are aligned end-to-end in the same plane and welded along the seam between them.
Other Skilled Trades Welding 1
What does the acronym MIG stand for in MIG welding?