Flux-cored wire is a consumable used in continuous-feed arc welding, consisting of a metal casing containing a core of flux or metal powder. This category includes gasless or self-shielded flux-cored wire, which provides the necessary protection as its core melts and does not require an external gas supply.
What is gas-free flux-cored wire?
Gasless flux-cored wire, also known as self-shielded wire, generates its own chemical and gaseous protection as the flux core melts during the arc, and therefore requires no gas cylinder or external flow meter. The process is carried out using direct current and produces a layer of slag that protects the weld bead as it cools, in a similar way to the coating on an electrode.
Differences compared with other types of flux-cored wire
Not all flux-cored wires work in the same way. Metal-cored, rutile and basic wires do require external shielding gas to form the weld bead correctly, whereas self-shielded wires do not require it at all:
Type of flux-cored wire | Requires shielding gas | Typical application |
| Metal cored | Yes | Structures and high-productivity work |
| Rutile | Yes | Flat position, good weld bead finish |
| Basic | Yes | Joints subject to higher mechanical stresses |
Self-shielded (no gas) | No | Outdoor work, construction sites or areas without a gas supply |
Advantages of gas-free flux-cored wire
As it does not rely on bottled gas, gasless flux-cored wire is more practical for construction work, field maintenance or outdoor work exposed to the wind, where a draught could displace the shielding gas and cause porosity in the weld bead. It also simplifies the set-up of the equipment, as it avoids the need to transport gas cylinders, and makes it easier to work in hard-to-reach areas.
On the other hand, it tends to produce more smoke and spatter than a gas-based process, and its surface finish is somewhat less clean; consequently, it is mainly used on structures and for jobs where functionality takes precedence over aesthetic finish.
When to choose gas-free flux-cored wire
It is advisable to use gasless flux-cored wire when working outdoors, on site or in any environment where a gas supply is not feasible or where wind could compromise the protection of the molten pool. For workshop work, in a controlled position and where the finish of the weld bead is a priority, a gas-shielded flux-cored wire or a solid MIG/MAG wire usually offers better results.
At CHAVESBAO, we stock the equivalent of E71T-11, a self-shielded flux-cored wire complying with the European standard UNE-EN ISO 17632-A, available in diameters of 0.9, 1.2 and 1.6 mm for use with direct current without the need for shielding gas. Check out the flux-cored wire category and consult our technical team to determine which product best suits your process and working conditions.
