Which statement best differentiates shielding methods between GMAW and FCAW?

Which statement best differentiates shielding methods between GMAW and FCAW?

• A. GMAW uses external shielding gas; FCAW uses flux-core shielding (which can be self-shielded or gas-shielded depending on the wire)
• B. GMAW uses flux-core shielding; FCAW uses external shielding gas
• C. Both require external shielding gas
• D. GMAW uses no shielding

Answer: (A)

Shielding method is what distinguishes these two processes. GMAW relies on shielding gas supplied from an external bottle to protect the weld pool from the atmosphere. FCAW uses a flux-core electrode; the shielding comes from the flux inside the wire, and it can either shield on its own (self-shielded) or work with an external shielding gas (gas-shielded) depending on the wire chosen. That’s why the best description is that GMAW uses external shielding gas, while FCAW uses flux-core shielding that may be self-shielded or gas-shielded. The other options mix up which process uses flux-core shielding or incorrectly claim that both require external gas or that GMAW has no shielding.

Shielding method is what distinguishes these two processes. GMAW relies on shielding gas supplied from an external bottle to protect the weld pool from the atmosphere. FCAW uses a flux-core electrode; the shielding comes from the flux inside the wire, and it can either shield on its own (self-shielded) or work with an external shielding gas (gas-shielded) depending on the wire chosen. That’s why the best description is that GMAW uses external shielding gas, while FCAW uses flux-core shielding that may be self-shielded or gas-shielded. The other options mix up which process uses flux-core shielding or incorrectly claim that both require external gas or that GMAW has no shielding.