Applications of Flux-Cored Welding
The heart of the flux-cored arc welding process is the tubular wire electrode that makes the FCAW process fundamentally different from MIG. Rather than just conducting an electric arc and providing filler to the molten weld pool, the tubular construction of the flux-cored wires allows it to be packed with slag formers similar in nature to those found on the outside of stick electrodes used for SMAW.
Whether the wire is designed for use with external shielding gas (an FCAW-G wire) or without (an FCAW-S wire), the core of these flux cored wires must serve double (and sometimes) triple-duty. They can alloy the weld pool and remove impurities to help improve the strength and toughness of the completed weld. Impurities are removed from the weld pool through slag formation, but the slag also helps support and shape the solidifying weld metal.
In short, the slag is what makes the process unique and provides flux cored arc welding with unique benefits for a wide range of applications.
Application One: Outdoor Structural Welding
Gas-shielded processes such as MIG are not generally recommended when the wind speed in the area of welding exceeds 5 miles per hour. However, when the weather is not cooperating with a pressing deadline, or maybe you are working in an offshore location, self-shielded flux-cored electrodes are the most economical means of completing critical welding jobs. Unlike gas-shielded wires, self-shielded wires can generate a sufficient volume of atmosphere-displacing gas to maintain weld quality even when the wind picks up.
But a porosity-free weld is only part of what makes the self-shielded flux cored electrodes a staple on construction sites nationwide. Wires intended for heavy-duty applications such as bridge and skyscraper erection need specially designed wires that provide excellent mechanical properties such as toughness to resist many natural and artificial forces. With one of these tough flux-cored wires and a well-designed welding procedure, it is possible to quickly and economically deposit weld metal on demand or fracture-critical structural components such as seismic-force restraint systems.
Application Two: Outdoor Home, Farm & Ranch Repairs
Of course, only some applications consist of splicing columns and making moment connections that exceed several inches in thickness. For those other applications, the modern “seismic” flux-cored wire is often too large in diameter for thinner materials and undoubtedly not as user-friendly.
To meet the needs of repairs around the home and farm, self-shielded flux cored wires exist that are smaller in diameter and easier to be successfully wielded by a broader range of skill levels. Like their large-diameter counterparts, these wires are still suitable for being brought to the outdoor workpiece. Still, the smaller diameter makes welding thinner materials, such as fencing, much easier with less risk of burn-through.
Application Three: Out-of-Position Welding
Flux-cored wires also can facilitate high-quality welding “out-of-position.” Not all welds can be easily made “in-position” with the weld joint resting on the workbench. In the production environment, it can be economical to invest in equipment that helps to allow easy movement of the workpiece to “position” parts. Still, for complex weldments, this may be a luxury.
Flux-cored wires have a unique advantage of a slag that solidifies to support molten metal when welding in the vertical and overhead positions. With high-quality welding wire and good technique, it is possible to produce very flat welds that can be difficult to distinguish from in-position welds.
It is possible to use MIG to weld out-of-position, but both deposition rate (productivity) and weld penetration will suffer compared to those all-position flux cored wires.
Unfortunately, not all flux-cored wires are suitable for welding out-of-position, but those that can are often classified and marketed as such. Wires intended for in-position welding only are often available in larger diameters and have a slower freezing slag that allows for high-amperage welding parameters to achieve the highest travel speeds.
Application Four: Rust, Scale, and Weldable Primer
Those who weld within the construction industry, know that bridges and skyscrapers start in the beam fabrication shop, where steel webs and flanges are joined into structural shapes such as angle, channel, and I-beams. Although every shop is different, many beam fabricators perform work in enclosed structures. However, raw materials are often stored in outdoor locations with at least some environmental exposure that leads to rust or necessitates the benefits of mill scale and weldable primer.
Although removing all potential contaminants from the base metal is “best practice,” it often becomes complicated to justify in the production environment as the part size increases. To maintain control of productivity and profitability, leveraging the welding process itself can be helpful. Remember that the slag of the flux-cored welding process helps to remove impurities from the weld metal to maintain good weld quality.
Application Five: The Heavy Duty
FCAW manufactures various components ranging from consumer goods to refinery components. Each of these applications demands different weld deposit chemical compositions to ensure the welds perform satisfactorily. Just as you can purchase wires for welding indoors or outdoors, or out-of-position versus in-position only, flux-cored wires are available in compositions ranging from carbon and low-alloy steel to nickel super-alloys and everything in between.
The flux-cored wire market is vast, meaning there are plenty of wires to choose from. However, if you are considering selecting flux-cored arc welding for your particular application, first consider the following:
Will you be welding outdoors? If so, you may benefit from a self-shielded flux-cored wire. If not, a gas-shielded flux-cored wire may still help tackle dirty base material with less prep work.
Will you be welding out-of-position? If so, you may benefit from an all-position flux-cored wire. Even still, large-diameter gas-shielded flux-cored wires can achieve deposition rates challenging to obtain with MIG.
What kind of mechanical property requirements does your application demand? Chances are good that a flux-cored wire exists that will help you strike the best balance between optimal properties and productivity.
If you’re still unsure, reach out to the Red-D-Arc team! We have extensive experience with applications of flux cored arc welding ranging from field to shop. Contact us today to learn more and select the rental equipment you need to complete your job today!
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