What is Flux Core Welding?

by WeldingWatch

First introduced to the industry in the 50s, Flux Core Welding is a type of welding that can be executed with or without the use of shielding gas.

Apart from that, it does share a lot in common with MIG welding, in that it uses the power supply, very similar equipment, and a continuous wire feed.

As well as offering a form of welding that doesn’t require a shielding gas, one of the biggest advantages of Flux core arc welding, often referred to as no gas welding, is that it is much more productive. In the following post, we are going to look at the method in greater detail, how it works, its suitability, and a lot more.

How Does Flux Core Welding Work?

Flux core welding involves an electric arc being used to combine a filler metal electrode that is running continuously with a base material. Unlike MIG welding that uses a solid metallic electrode, Flux core welding uses a tubular electrode that is hollow and filled with flux. The electrode filled with flux is fed automatically through the gun’s center with the same kind of equipment used in MIG welding. Depending on what method you use, you can either have gas produced by the gun to protect the weld pool from the effects of oxidation or the flux from the electrode that forms a protective covering that protects the weld pool from oxidation.

Although it won’t make much difference which method you use if you are indoors, when you are welding outdoors and there is a lot of wind, gasless flux core welding is a more effective and efficient choice.

Flux Core Welding Suitability and Application

It is probably one of the most flexible welding methods and is ideal for use in all position welding when you use the right filler flux and metal combination. Part of what makes it so highly productive is its high deposition rates, which not only ensure you have a robust and durable weld, but one that looks great too.

You will find that this form of welding often lends itself to work with thicker pieces and can produce a weld that is fully-penetrated at either side of a plate measuring half-inch in one pass.

Materials that are best for flux core arc welding are low-alloy steels, stainless steel, and carbon steel. One major downside of flux core welding is that non-ferrous metals like aluminum are not compatible.

Frequently Asked Questions:

What is Weld Flux?

You may wonder with all this talk of flux, if you are unfamiliar with the terminology or are just new to welding, what flux is. It is a combination of silicate and carbonate materials. When the heat generated from the weld puddle reaches the flux, in this case, found inside the electrode, it melts down and outgasses. Gases that are produced from this reaction push all the atmospheric gases back and prevent oxidation (involving oxygen and other reactions involving nitrogen) from affecting the quality of the weld.

What is 7018 Flux Made From?

When looking into flux core welding, you will come across what is known as 7018 flux and a 7018 arc welding rod. This is used most commonly when welders are working with carbon steel for more general purposes. It involves a rod made from mild steel that has a coating of iron-based, low-hydrogen flux that works in the same way as other flux.

What do the letters and numbers mean? In an E7018 electrode, the E highlights that it is used for arc welding. While the 70 relates to the strength of the welds it is made, of up to 70,000psi. The 18 is interesting and can mean a couple of things – 1 indicates it is usable in all positions, while the 18 indicates a DC is used and that it is low hydrogen.

Is Flux Core Arc Welding Easy?

This is an important question, especially if you are just starting in welding or are looking to change the method you use. The great thing about flux core welding is that you can do it right out of the box, especially if you are not using any gas with it.

Which is Best Solid Wire or Flux Core Wire?

We have touched on this subject at other points in the post, but as it is a question that is asked regularly, we felt it was important to also look at it separately. When you are comparing flux core wire electrodes to solid wire electrodes and trying to figure out which is best, there is no set answer. It all depends on two things – the type of welding work you plan on doing and the location.

Both types of electrodes are effective for producing robust and durable welds that have great aesthetics if they are used properly.

When you are working with thicker metals and materials or outside, there is no question that flux core wire electrodes are the best option, whereas if you are working indoors and with much thinner materials, solid wire electrodes are often best.

If portability is a factor for you and you need to be able to easily transport your welding gear from one place to another, you should consider flux core wire electrodes, because you don’t necessarily need to use a shieling gas. However, for solid wire electrodes in MIG welding, you do.

Probably the biggest difference is the price. While you don’t need to pay out for a supply of shielding gas, the actual flux core wire electrodes themselves are more expensive than the solid wire electrodes.


We hope you have found our guide to flux core welding useful. If you were still on the fence about it before you read this post, then we hope you have a clearer viewpoint and idea of what you want to invest in for your welding jobs.

In the end, it will come down to the type of welding you are doing, the materials you are working with, and where you will be completing the welding as to what is your best option.

You can find out more about other forms of welding and related subjects by checking out the other blogs on this site.

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