IMM Welding & Fabrication 2 — Questions and Answers
Question 1: In the electrode designation E7018, what does the number '70' represent?
- Electrode diameter in thousandths of an inch
- Minimum tensile strength of the deposited weld metal in ksi (Correct answer)
- Recommended welding current in amperes
- Percentage of iron powder in the flux coating
Correct answer: Minimum tensile strength of the deposited weld metal in ksi
The digits '70' in E7018 indicate a minimum tensile strength of 70,000 psi (70 ksi) for the weld deposit in the as-welded condition.
Question 2: What type of oxy-acetylene flame is used when welding cast iron?
- Oxidizing flame
- Neutral flame
- Carburizing (reducing) flame (Correct answer)
- Hydrogen flame
Correct answer: Carburizing (reducing) flame
A slightly carburizing flame is used for cast iron to add carbon to the weld zone and compensate for carbon burn-off during the welding process.
Question 3: What does FCAW stand for?
- Full-Current Arc Welding
- Flux-Coated Arc Welding
- Flux-Cored Arc Welding (Correct answer)
- Forge-Control Arc Welding
Correct answer: Flux-Cored Arc Welding
FCAW stands for Flux-Cored Arc Welding, which uses a tubular wire electrode with a flux-filled core to shield and protect the weld pool.
Question 4: What is the primary purpose of a backing bar (backing strip) placed behind a weld joint?
- To preheat the base metal to welding temperature
- To support the molten weld pool and ensure full root penetration on single-sided welds (Correct answer)
- To regulate amperage fluctuations during welding
- To prevent warping of thin sheet metal
Correct answer: To support the molten weld pool and ensure full root penetration on single-sided welds
A backing bar supports the molten root pass from below, allowing full-penetration welds to be made from one side without burn-through.
Question 5: What causes porosity in a completed weld?
- Excessively slow travel speed during welding
- Gas entrapped in the solidifying weld metal forming voids (Correct answer)
- Amperage set too high for the electrode diameter
- Improper groove angle on the joint preparation
Correct answer: Gas entrapped in the solidifying weld metal forming voids
Porosity occurs when gases such as hydrogen, nitrogen, or oxygen become trapped in the solidifying weld pool before they can escape, forming voids or bubbles.
Question 6: What travel angle is typically used with a drag technique during flat-position SMAW welding?
- 90° perpendicular to the base metal surface
- 45° to the direction of travel
- 10–15° from vertical in the direction of travel (Correct answer)
- 30° away from the direction of travel
Correct answer: 10–15° from vertical in the direction of travel
A 10–15° drag (travel) angle directs arc force slightly forward into the joint, improving penetration and bead shape in the flat position.
Question 7: Which weld joint configuration is formed when two pieces of metal are aligned end to end in the same plane?
- T-joint
- Lap joint
- Butt joint (Correct answer)
- Corner joint
Correct answer: Butt joint
A butt joint is created when two pieces of metal are placed edge to edge in the same plane and welded along their abutting edges.
IMM Welding & Fabrication 2
In the electrode designation E7018, what does the number '70' represent?