Which statement best describes shielding requirements for solid wire MIG versus flux-cored MIG?

Which statement best describes shielding requirements for solid wire MIG versus flux-cored MIG?

• A. Solid wire does not require shielding gas.
• B. Flux-cored wire never uses shielding gas.
• C. Solid wire uses shielding flux instead of gas.
• D. Solid wire requires external shielding gas; flux-cored wire provides shielding via flux, which may be self-shielded or gas-shielded depending on the core.

Answer: (D)

The key idea is how shielding is provided in MIG welding for solid wire versus flux-cored wire. Solid wire relies entirely on shielding gas from an external source to protect the weld pool from the atmosphere, since the wire itself contains no flux to generate its own shielding. Flux-cored wire contains flux inside the wire; that flux can create shielding gas and/or slag. Because of that, flux-cored wires can shield the weld either without any external gas (self-shielded) or with external shielding gas (gas-shielded) depending on the core design. So solid wire requires external shielding gas, while flux-cored wire may shield themselves or may need gas depending on the core. The other statements don’t fit because solid wire does require shielding gas, flux-cored wires can use shielding gas, and solid wire does not rely on a shielding flux.

The key idea is how shielding is provided in MIG welding for solid wire versus flux-cored wire. Solid wire relies entirely on shielding gas from an external source to protect the weld pool from the atmosphere, since the wire itself contains no flux to generate its own shielding. Flux-cored wire contains flux inside the wire; that flux can create shielding gas and/or slag. Because of that, flux-cored wires can shield the weld either without any external gas (self-shielded) or with external shielding gas (gas-shielded) depending on the core design. So solid wire requires external shielding gas, while flux-cored wire may shield themselves or may need gas depending on the core. The other statements don’t fit because solid wire does require shielding gas, flux-cored wires can use shielding gas, and solid wire does not rely on a shielding flux.