456A FCAW 2 — Questions and Answers
Question 1: When should slag be removed between passes in multi-pass FCAW welding?
- Only after the final pass
- All slag must be completely removed between every pass using a chipping hammer and wire brush to prevent slag inclusions (Correct answer)
- Only if the slag doesn't look right
- Slag removal is optional in FCAW
Correct answer: All slag must be completely removed between every pass using a chipping hammer and wire brush to prevent slag inclusions
Complete slag removal between every pass is mandatory in FCAW to prevent slag inclusions — one of the most common defects in flux-cored welding. Use a chipping hammer to break the slag, followed by vigorous wire brushing. Pay special attention to the toes of the weld and any undercuts where slag can become trapped.
Question 2: What CSA standard governs the use of FCAW in structural steel welding in Canada?
- CSA W47.1 only
- CSA W59 (Welded Steel Construction) specifies the requirements, and CSA W47.1 (Certification of Companies for Fusion Welding of Steel) governs company certification (Correct answer)
- No specific standard exists for FCAW
- Only the National Building Code covers welding
Correct answer: CSA W59 (Welded Steel Construction) specifies the requirements, and CSA W47.1 (Certification of Companies for Fusion Welding of Steel) governs company certification
CSA W59 provides the technical requirements for welded steel construction in Canada, including approved processes (FCAW is listed), preheat requirements, WPS requirements, and acceptance criteria. CSA W47.1 certifies welding companies and requires welders to be qualified under supervised testing. Both standards reference FCAW as an approved process.
Question 3: What are the advantages of gas-shielded FCAW (FCAW-G) over solid-wire GMAW?
- FCAW-G is always cheaper
- Higher deposition rates, better out-of-position performance, greater tolerance for mill scale and surface contaminants, and deeper penetration capability (Correct answer)
- FCAW-G produces no spatter
- FCAW-G requires no slag removal
Correct answer: Higher deposition rates, better out-of-position performance, greater tolerance for mill scale and surface contaminants, and deeper penetration capability
Gas-shielded FCAW offers several advantages over solid-wire GMAW: higher deposition rates (more metal deposited per hour), better performance in vertical and overhead positions due to the slag support, greater tolerance for surface contaminants, and typically deeper penetration. The trade-off is the need for slag removal between passes.
Question 4: What filler wire classification does E71T-1C/1M represent?
- A solid GMAW wire
- A gas-shielded flux-cored wire: E = electrode, 7 = 70 ksi tensile, 1 = all positions, T = tubular (flux-cored), 1 = usability/performance, C = CO₂ shielding (M = mixed gas) (Correct answer)
- A SMAW electrode
- A submerged arc wire
Correct answer: A gas-shielded flux-cored wire: E = electrode, 7 = 70 ksi tensile, 1 = all positions, T = tubular (flux-cored), 1 = usability/performance, C = CO₂ shielding (M = mixed gas)
In the AWS/CSA classification: E = electrode, 7 = minimum tensile strength (70,000 psi / 490 MPa), 1 = all-position capability, T = tubular (flux-cored), 1 = usability and performance characteristics, C = designed for CO₂ shielding, M = designed for mixed gas (argon/CO₂). E71T-1 is the most widely used structural FCAW wire.
Question 5: What is the proper technique for FCAW vertical-up welding?
- Use the same settings as flat position
- Reduce voltage and wire feed speed compared to flat position, use a weave or stringer technique with pauses at the toes, and maintain proper stick-out (Correct answer)
- Weld downhill for better penetration
- Increase voltage for better flow
Correct answer: Reduce voltage and wire feed speed compared to flat position, use a weave or stringer technique with pauses at the toes, and maintain proper stick-out
Vertical-up FCAW requires reduced parameters (typically 10-15% less voltage and WFS compared to flat) to control the puddle against gravity. Use a weave or oscillation technique with brief pauses at the toes to ensure fusion. Maintain consistent stick-out and a slight drag angle. The slag helps support the puddle in vertical position.
Question 6: What storage requirements apply to FCAW wire to maintain weld quality?
- No special storage is needed
- Store in a dry, controlled environment away from moisture, dirt, and contaminants; reseal opened packages; some wires require heated storage similar to low-hydrogen SMAW electrodes (Correct answer)
- Store underwater to prevent oxidation
- Store in direct sunlight for warmth
Correct answer: Store in a dry, controlled environment away from moisture, dirt, and contaminants; reseal opened packages; some wires require heated storage similar to low-hydrogen SMAW electrodes
FCAW wire must be stored in a clean, dry environment to prevent moisture absorption by the flux core (which causes porosity and hydrogen cracking). Opened packages should be resealed or the wire kept in a heated cabinet. Some low-hydrogen FCAW wires have specific storage requirements similar to E7018 SMAW electrodes. Contaminated or rusty wire should be discarded.
456A FCAW 2
When should slag be removed between passes in multi-pass FCAW welding?