What Is Flux-Cored Welding?

Jun 27, 2019 ·

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Flux-cored welding, also known as flux-cored arc welding (FCAW), is a type of welding that is suitable for the outdoors, enabling welders to meld metals and other materials together by applying heat and pressure.

If you’ve wondered, “What is flux-cored welding, and how does it differ from other types?” know that during flux-cored welding a continuous hollow wire electrode is fed through the welding gun. It is similar to gas metal arc welding (also known as GMAW or metal inert gas [MIG] welding) in the type of power supply it uses. But unlike GMAW, FCAW does not require an external shielding gas.

This is because a flux compound within the wire protects the weld pool by forming a gas as it reacts with the welding arc. This makes FCAW an ideal type of welding for dirty, rusty and contaminated materials.

Keep reading if you would like to learn more about FCAW.

What Is FCAW Used For?​

FCAW is a good technique to use on materials that are no thinner than 20 gauge, including carbon steel, low-alloy steels, high-nickel alloys, cast iron and stainless steels. The flux-cored wire is powerful and able to penetrate into thick weld joints.

FCAW is often used in the construction industry, since this semi-automatic type of welding can be used outdoors, has a high welding speed and is easily portable.

FCAW can be used for jobs like:

  • Shipbuilding
  • Construction
  • Water tank repairs

When a welder needs to work outdoors or on contaminated materials, FCAW can produce high amounts of welds in a short amount of time.

Advantages of FCAW

Several advantages make FCAW a popular welding choice, including:

  • Increased mobility: Since flux-cored welding contains its own shielding method, it doesn’t require an external gas and can be transported easier.
  • High deposition rate: The rate of deposition in flux-cored welding is the highest of any welding method, increasing productivity. Deposition rate refers to the amount of filler metal melted into the weld joint.
  • Versatility: Flux-cored welding can be performed in a variety of positions when the right filler material is used.

Disadvantages of FCAW

While there are many pros to FCAW, there are still some cons to consider:

  • Fumes: FCAW needs to be performed in a well-ventilated area because it produces a large amount of fumes from the high deposition rate.
  • Cleanup: Flux-cored welding is a process that produces slag, a layer of byproduct that takes time to be removed after a weld.
  • Expense: Equipment used in FCAW processes tends to be more expensive and complex, including the electrode wire.

How Flux-Cored Welding Works​

Wondering more about the specific process and other details of flux-cored welding? We have you covered.

Flux-Cored Welding Process

In FCAW, an electric arc unites a continuous filler metal electrode with the base material. As the welding process happens, the shield gas provided by the flux protects the weld pool from oxidation and other atmospheric elements.

After the weld is completed, there is slag that must be removed. Welders need to account for time to remove slag to make the weld look clean.

Flux-Cored Welding Techniques

There are a few different processes a welder can use when performing flux-cored welding. These variants include self-shielded FCAW and gas-shielded FCAW.

There are different fluxing agents with each that provide different benefits to the welder. Self-shielded FCAW is typically used outdoors because FCAW using a separate gas shield would have issues with wind potentially blowing it away.

Flux agents used in gas-shielded processes are designed to help deliver deeper penetration and work with out-of-position welds. Gas-shielded welds are also known as dual shields because flux-cored welds already rely on the electrode for shielding.

Flux-Cored Welding Patterns

There are a variety of welding patterns that can be achieved with flux-cored welds. High and narrow welds, for example, can be achieved by using a backhand welding method.

There is a stringer bead method that deposits weld beads in a straight line, as well as a weave bead technique that forms a zigzag pattern.

Flux-Cored Welding Wire Types

Wires for flux-cored welding differ depending on whether the process is self-shielded or gas-shielded. Self-shielded wires, or FCAW-S, don’t need an external gas cylinder. They are often used for portable jobs but do tend to produce more smoke and spatter.

Gas-shielded wires, or FCAW-G, require external shielding gas. They are easier to control and produce welds that are aesthetically pleasing. Typically they are used in shop settings, as outside the gas could blow around.

FCAW-G wires tend to be less expensive than FCAW-S wires. Both wires are typically available in diameters ranging from .035 to 7/64 of an inch.

Flux-Cored Welding Polarity​

The polarity for flux-cored welding processes depends on whether they are self-shielded or gas-shielded. The majority of gas-shielded welds work the best with a direct-current electrode positive (DCEP) polarity. When using a self-shielded process, direct-current electrode negative (DCEN) polarity is used.



Flux-Cored Welding Classes

FCAW is one of the main components of the Welding Technology program at Universal Technical Institute (UTI). In the program, students are introduced to welding tools including hand grinders, pedestal grinders, plasma cutters, CNC pipe cutters and more. State-of-the-industry equipment is provided by Lincoln Electric, a leading brand in welding equipment.

Students learn about subjects including general safety and safe operation, math that’s practical to welding industry fabrication, welding theory, metallurgy, advanced welding machine functions, the science behind welding and hands-on welding applications. Students take a specific FCAW course, which builds upon stick-welding skills, so that they learn how to perform overhead, vertical and horizontal welding operations.

Students will then apply those skills in Welding Applications I, where they’ll use blueprinting and project planning skills to fabricate specific projects using FCAW welding.

“Students choose this program because they like to work with their hands,” says Edward Lopez, welding technical team leader at UTI Rancho Cucamonga. “They want to choose an industry that pays very well and will be in demand for many years to come.”6

Attend One of Our Welding Campus Locations

FCAW is just one of the welding processes students learn while training at UTI. They’ll also learn how to perform three other kinds of arc welding processes in the labs at one of campus locations nationwide:

You can click on any one of the locations listed above for more specific information about each campus and what benefits they have to offer. To find out more about the welding program, contact us.

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1) UTI is an educational institution and cannot guarantee employment or salary.

2) For program outcome information and other disclosures, visit

6) UTI graduates’ achievements may vary. Individual circumstances and wages depend on personal credentials and economic factors. Work experience, industry certifications, the location of the employer and their compensation programs affect wages. UTI is an educational institution and cannot guarantee employment or salary.

Universal Technical Institute of Illinois, Inc. is approved by the Division of Private Business and Vocational Schools of the Illinois Board of Higher Education.


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