What is flux cored welding wires (FCAW)?
Flux-Cored Arc Welding is a semi-automatic or automatic arc welding process that uses a continuously fed consumable electrode (the wire) that contains a flux compound inside a metal sheath. The process can use shielding gas (often called "dual-shield") or be self-shielding, making it incredibly versatile.
How Does flux cored welding wire Work?
The core concept is that the wire itself contains materials that facilitate the welding process. When the arc is struck, several things happen simultaneously:
The metal sheath melts: This forms the weld metal, fusing with the base material.
The flux core reacts: The heat from the arc causes the flux compounds to react, performing one or more critical functions:
Forming a Slag Covering: The flux creates a protective layer of slag over the molten weld pool as it cools. This slag protects the hot metal from atmospheric contamination (oxygen and nitrogen), shapes the weld bead, and helps it cool evenly.
Providing Shielding Gas: In many wires, the flux produces a shielding gas vapor that further protects the arc and weld pool.
Deoxidizing and Purifying: The flux contains deoxidizers (like silicon and manganese) that "scavenge" impurities from the weld pool, resulting in a cleaner, stronger weld. This is especially useful on slightly rusty or dirty metal.
Adding Alloying Elements: The flux can add specific alloys to the weld metal to achieve desired mechanical properties like strength, toughness, or corrosion resistance.
Stabilizing the Arc: Compounds in the flux help maintain a stable and consistent arc.
