Why might SAW filler wires be copper-coated?

• A. To prevent rusting.
• B. To increase magnetic properties.
• C. To make the wire black.
• D. To reduce melting point.

Answer: (A)

Copper coating on SAW filler wires is used mainly to protect the steel core from corrosion. The copper layer acts as a barrier against moisture and air, reducing rust on the wire surface during storage and handling, which helps prevent surface flaws that could affect weld quality. In addition, copper’s high electrical conductivity aids smooth current transfer from the power source through the wire to the arc, contributing to stable arc behavior in the submerged arc process. The other options don’t fit because the coating isn’t intended to alter magnetic properties, color, or melting point of the wire.