Welder Red Seal · Question
An apprentice welder is struggling to achieve consistent penetration and suffers from excessive porosity when using GMAW on stainless steel. They are currently using a 75% Argon / 25% CO2 shielding gas mixture. What change in shielding gas would most likely resolve these issues?
75% Argon / 25% CO2 is generally not recommended for stainless steel as CO2 can destabilize the arc and cause carbon pickup, leading to reduced corrosion resist
Start free practice for Welder Red Seal
154 questions · no signup required · 40 free questions per day
Question: An apprentice welder is struggling to achieve consistent penetration and suffers from excessive porosity when using GMAW on stainless steel. They are currently using a 75% Argon / 25% CO2 shielding gas mixture. What change in shielding gas would most likely resolve these issues?
Answer options: ✅ Switch to an Argon + 2% Oxygen mixture.
- Increase the CO2 content to 100%.
- Switch to 100% Argon.
- Decrease the gas flow rate.
Correct answer: Switch to an Argon + 2% Oxygen mixture.
Explanation: 75% Argon / 25% CO2 is generally not recommended for stainless steel as CO2 can destabilize the arc and cause carbon pickup, leading to reduced corrosion resistance and porosity. An Argon + 2% Oxygen mixture provides better arc stability, puddle fluidity, and reduces porosity when GMAW welding stainless steel. 100% CO2 would worsen the issue, and 100% Argon might lead to poor bead profile and wetting.
Start free practice for Welder Red Seal
154 questions · no signup required · 40 free questions per day
More about Welder Red Seal
Related Questions
- A welder is fabricating a pressure vessel component using FCAW-G with an E70T-1 wire. The procedure specifies
- A welder is preparing to weld 20 mm (0.8 in) thick high-strength low-alloy (HSLA) steel using FCAW-G. The weld
- A structural steel fabricator is using FCAW-S (E71T-8 wire) to weld heavy sections of structural steel in an o
- When performing FCAW-G (gas-shielded flux-cored arc welding), a welder notices the arc is unstable and the wir
- A structural welder is performing overhead FCAW-G on 12 mm (0.5 in) thick steel with an E71T-1 wire. The weld
- A welder is setting up an FCAW-S machine for welding in a remote location without access to external shielding
More for Welder Red Seal candidates
Practice tests
Question explanations
- A welder is fabricating a pressure vessel component using FCAW-G with an E70T-1 wire. The procedure specifies
- A welder is preparing to weld 20 mm (0.8 in) thick high-strength low-alloy (HSLA) steel using FCAW-G. The weld
- A structural steel fabricator is using FCAW-S (E71T-8 wire) to weld heavy sections of structural steel in an o
- When performing FCAW-G (gas-shielded flux-cored arc welding), a welder notices the arc is unstable and the wir
Ready to practice?
Free, no signup required. Build a wrong-question list as you go.
Start Free Welder Red Seal Practice →Related courses
Other Canadian certifications candidates often prepare for alongside this one.