In FCAW, the need for shielding gas depends on the flux used.

• A. True
• B. False
• C. Only for some flux
• D. Shielding gas is never needed

Answer: (A)

In FCAW, shielding gas requirements hinge on the flux inside the tubular wire. Some flux-cored wires are designed to provide all the shielding from the flux and slag they produce, so no external shielding gas is needed (self-shielded FCAW). Others are intended to be used with shielding gas to protect the weld pool, with the gas helping to stabilize the arc and control penetration (gas-shielded FCAW). Because the flux formulation determines whether external gas is required, the statement is true. If you use a self-shielded flux, you don’t run gas; if you use a gas-shielded flux, you supply shielding gas such as CO2 or an Argon-CO2 blend.