The electrode code ER70S-2 indicates the electrode wire is for which material?

• A. Mild steel electrode wire
• B. Stainless steel electrode wire
• C. Aluminum electrode wire
• D. Copper electrode wire

Answer: (A)

ER70S-2 is a carbon steel filler metal used for welding mild steel. The “ER” identifies an arc-welding filler metal, the “70” means about 70 ksi minimum tensile strength of the weld, and the “S” indicates a solid wire. The “-2” suffix is a deoxidizer package that helps produce a stable weld with good quality. This combination is specific to carbon/mild steel, not stainless, aluminum, or copper, so it’s the right choice for mild steel electrode wire.