AWS Filler Metals & Consumables 4 — Questions and Answers
Question 1: Which AWS filler metal classification prefix indicates a bare solid wire electrode for GMAW?
- ER (Correct answer)
- E
- R
- EC
Correct answer: ER
The 'ER' prefix denotes a wire that can be used as either an electrode or a rod, which is standard for GMAW solid wires.
Question 2: What does the 'G' suffix in an E71T-1C-H8 flux-cored wire classification indicate?
- General-purpose shielding
- Meets supplemental impact and diffusible hydrogen requirements
- Gas-shielded only
- No specific requirements beyond the base classification (Correct answer)
Correct answer: No specific requirements beyond the base classification
The 'G' suffix means the wire meets no requirements beyond those already specified in the base classification.
Question 3: A welding procedure requires a filler metal with a minimum tensile strength of 80,000 psi for carbon steel SMAW. Which electrode class is the minimum requirement?
- E6010
- E7018
- E8018 (Correct answer)
- E9018
Correct answer: E8018
The 'E80XX' series designates a minimum tensile strength of 80,000 psi; E8018 meets this requirement.
Question 4: What is the primary purpose of lithium fluoride in a SAW flux?
- Increase deposition rate
- Reduce weld bead width
- Lower arc voltage requirements
- Improve slag detachability and reduce fluorine fumes (Correct answer)
Correct answer: Improve slag detachability and reduce fluorine fumes
Lithium fluoride in SAW fluxes improves slag removal and helps reduce the overall fluorine fume generation compared to calcium fluoride alone.
Question 5: When welding austenitic stainless steel, which filler metal composition is used to prevent weld solidification cracking by promoting a small amount of ferrite?
- Fully austenitic with no ferrite
- Dual-phase with 3–8 FN ferrite number (Correct answer)
- Martensitic with high carbon
- Ferritic with minimal nickel
Correct answer: Dual-phase with 3–8 FN ferrite number
A ferrite number of 3–8 FN in the weld deposit provides enough ferrite to dissolve sulfur and phosphorus, preventing hot cracking.
Question 6: Which shielding gas mixture is most commonly specified with ER70S-6 wire to achieve a spray transfer mode in GMAW?
- 100% CO2
- 75% Ar / 25% CO2
- 90% Ar / 10% CO2 (Correct answer)
- 50% Ar / 50% He
Correct answer: 90% Ar / 10% CO2
A high-argon mix of 90% Ar / 10% CO2 (or similar) provides the stable arc needed for spray transfer with ER70S-6.
Question 7: According to AWS A5.1, what does the digit '8' in the E7018 classification specifically indicate?
- Flat and horizontal position only
- Low-hydrogen potassium coating, AC or DC+ (Correct answer)
- Iron powder titania coating
- High cellulose sodium coating
Correct answer: Low-hydrogen potassium coating, AC or DC+
The suffix '8' in AWS A5.1 designates a low-hydrogen potassium (LHK) coating usable with AC or DC+ polarity.
AWS Filler Metals & Consumables 4
Which AWS filler metal classification prefix indicates a bare solid wire electrode for GMAW?