APPLICATION Engineer at the Lincoln Electric Company Ken Lee has written about the advantages and uses of flux-cored wire in welding applications.
Most welders find gas metal arc welding (GMAW) with a solid wire is satisfactory, but the higher-priced flux-cored wire is optimised to obtain performance beyond that a solid wire is capable of. Particularly, flux-cored wire performs better and faster in vertical-up welding, flat welding, welding over galvanised and welding hard-to-weld steels.
Additionally, GMAW with solid mild steel wire has various limitations and drawbacks. It is slow for out-of-position welding, is limited to short-circuit transfer or pulse transfer, and requires very clean steel.
Flux-cored wires allow a variety of materials to be added to the core of the welding wire. This means various performance enhancements are possible.
Slag formers, for example can be used to shield the weld pool and shape and support the weld. Iron powder can be used to increase deposition rates. Powdered alloys are added to produce low-alloy deposits and improve mechanical properties, while scavengers and fluxing agents are used to refine the weld metal.
There are two types of flux-cored welding wires. Gas-shielded wires requires gas to provide shielding, while self-shielded wires have core materials that generate its own shielding gases, slag formers and weld pool refining compounds. Both have their own advantages.
Gas-shielded wires allow for better welding performance and speed, while self-shielded ones can be used in adverse conditions without need for tenting and additional equipment required for gas shielding.

Leave a comment