What is Flux Cored Arc Welding?

Even if you’re familiar with gas metal arc welding (GMAW) and shielded metal arc welding (SMAW) - there’s a chance you might not have heard of flux cored arc welding (FCAW). FCAW, sometimes referred to as “dual shield welding”, was first developed in the 1950s as a welding system that functions through a continuously fed wire electrode. FCAW overcomes restrictions that are commonly associated with stick welding and is generally more productive than GMAW welding.

But how exactly does dual shield welding work? What can you expect when you tackle a project with this system, and what are the pros and cons? This article will cover all of that to help you get the best experience from dual shield welding.

How Does FCAW Work?

Flux cored arc welding is performed by using heat that is generated through an electric arc, enabling the arc to fuse base metal in the joint. The arc is struck between the tubular cored consumable filler wire and the metallic piece. The wire and the workpiece are melted together to form a weld joint. Sound similar to GMAW welding? There are certainly some major similarities, but the difference is FCAW utilizes a hollow electrode tube that is filled with flux as opposed to a solid metal electrode, as in the case of an GMAW project.

There are even different types of FCAW. One depends on the flux core to protect the weld area, and the other requires an external shielding gas. How does shielding gas work? When applied, a shielding gas protects the weld from oxidation. It is generally supplied through a high-pressure gas cylinder. Flux melting also results in a slag formation, which further protects the weld metal. This process is referred to as “dual shield”, which was developed mainly for structural steel welding. The more common shielding gasses are blends of carbon dioxide and argon or just carbon dioxide. A popular blend is 75% argon and 25% carbon dioxide. This blend makes for a sturdy shielding method, ideal for projects where thick materials are being welded and out-of-position welds.

What Are the Pros?

FCAW is ideal for outdoor welds and those involving thicker materials due to the built-in shielding supplied by the filler which is able to withstand strong breezes. When used without an external shielding gas, FCAW becomes an extremely portable and therefore convenient option. Additionally, FCAW is compatible with more alloy compositions than GMAW, as well as improved arc stability and higher wire deposition rates which allows for fast applications without sacrificing the quality of the weld.

Another perk to FCAW is that when applied correctly, the chances of porosity are very low. FCAW also calls for less metal pre-cleaning than other forms of welding.

What Are the Cons?

FCAW does come with its own set of disadvantages and limitations, which you need to be aware of before you decide to utilize this method. First of all, FCAW generates considerably more smoke than GMAW or SMAW, sometimes clouding the user’s view of the weld pool. Porosity is something you’ll need to consider as well since the gasses from the weld metal can’t be expelled before the weld metal is solidified.

FCAW electrodes also call for better storing and handling procedures in comparison to solid wire electrodes. Due to the tubular nature, filler material is often more expensive than the solid counterparts. Speaking of filler, FCAW means the appropriate filler metal has to be chosen for each use in order to secure the required mechanical properties.

Finally, another limitation of FCAW is that the slag formation requires removal prior to discarding each subsequent layer. This is an extra step that could make FCAW more time-consuming than other forms of welding.

M&M welders are Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), and American Welding Society (AWS) certified and have the needed skills and experience to tackle any welding job. Flux cored arc welding is just one of the many processes our welders use. Have questions? Feel free to contact M&M Certified Welding Co. if you have questions or would like a quote on a welding project — we're ready to help!