Skip to main content

Welder Red Seal · Question

A welder is preparing to weld a full penetration butt joint on 2 mm thick 316L stainless steel sheet. To prevent oxidation and sugaring on the root side, what is the most effective backing technique?

To prevent oxidation and sugaring on the root of stainless steel, it is crucial to displace oxygen with an inert gas. Flooding the back of the joint with argon

Start free practice for Welder Red Seal

154 questions · no signup required · 40 free questions per day

Start Practice →

Question: A welder is preparing to weld a full penetration butt joint on 2 mm thick 316L stainless steel sheet. To prevent oxidation and sugaring on the root side, what is the most effective backing technique?

Answer options:

  • Applying a thin layer of anti-spatter spray to the back of the joint.
  • Using a copper backing bar without gas purging. ✅ Flooding the back of the joint with argon shielding gas.
  • Using an open-air purge with CO2 for a short duration.

Correct answer: Flooding the back of the joint with argon shielding gas.

Explanation: To prevent oxidation and sugaring on the root of stainless steel, it is crucial to displace oxygen with an inert gas. Flooding the back of the joint with argon shielding gas (a gas purge) effectively creates an inert atmosphere, protecting the molten weld metal from atmospheric contamination. Anti-spatter is for spatter, copper backing without gas still allows oxidation, and CO2 is not an inert gas.

Start free practice for Welder Red Seal

154 questions · no signup required · 40 free questions per day

Start Practice →

More about Welder Red Seal

Related Questions

More for Welder Red Seal candidates

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.