Is Flux Core Welding Strong?

Flux core welding is a strong metal-combining process that produces solid welds. It delivers results that can withstand tension and stress for a long period. 

Fluid core welding can still produce quality output even if you weld in a windy open space. This process can also combine metals nicely and tight even if they’re contaminated with rust and dirt.

Is Flux Core Welding Strong?

Many consider flux core welding a strong process. Thanks to its excellent penetration capabilities. Flux core welding also uses electrode wires that produce heavy-duty weld joints.  

Yet, you can still improve the quality of the results. To do that, you have to consider a few things such as techniques, wire choice, metal types, etc. 

Flux Core Welding Strength vs MIG Welding

Flux core welding is often compared to MIG welding. We will discuss their similarities and differences in the following sections.  


Flux core and MIG welding are the same as how their welding wires work. Both processes won’t require you to keep on replacing their consumable electrodes. That’s because they both use continuous wire feeds. 

This automatic feeding process provides the weld with a constant supply of filler materials. Likewise, it helps the wire in supporting the welding arc. That said, both flux core and MIG welding could reduce work time and increase the production rate. 


Now that you’ve seen the similarities between flux core welding and MIG welding, let’s look at the things that set the two apart. 

Wire Build and Shielding Gas

One of the differences is the construction of their respective wires. Flux core welding uses tubular hollow electrodes while MIG uses solid welding wires. 

Unlike MIG welding which requires gas to shield the weld, flux core welding doesn’t need one. That’s because the wire’s hollowed core contains flux. This material produces shielding gas when heated. Also, the exclusion of gas tanks makes flux core welding more portable.

You can also use flux core welding in open spaces. The protective gas that flux core wires produce can shield the weld against the wind. One of the places you can use this welding process is construction sites. 

Wire Fillings

The hollow core of a flux-cored wire also contains materials apart from flux. This filler element’s main purpose is to help the welding wire work with certain metals. The only downside is that it makes multiple passes bad for the weld. 

MIG welding wires on the other hand are more fitting to take multiple passes. They have less chance of producing fragile joints and vulnerable welds. 

Penetration Capabilities

Flux core welding is better than MIG welding regarding its ability to penetrate. The former could even penetrate thick metals because it uses concentrated heat. With MIG welding, you must crank up the amperage to penetrate like its counterpart.

Flux core welding could likewise make its way through contaminated metals. You see, contaminants like rust cause weld bead porosity defects. This welding process could prevent the absorption of porosity-causing elements.

Strength Comparison

Both flux core and MIG welding produce results that aren’t far from each other. The two provide welds that could hold what it has to. While you can do multiple passes with MIG welding, it doesn’t make its output stronger than flux core welding.  

The bottom line is, the correct technique, proper execution, and the welder’s experience play a big part in producing strong welds.  

Tips to Improve Your Flux Core Welding Strength

If you’re new to this process, the tips below can help you improve your flux core welding strength.    

Avoid Burnback

Burnback happens when you set your wire with an incorrect feed speed. Setting it at low speed prematurely removes the arc and melts the wire into a ball. They could cause defects in the weld. 

It’s recommended you use the appropriate feed speed for your application. This will prevent burn-back from happening. Make sure to have a distance no further than 1.25 inches between the work and the contact tip.

Counter Birdnesting

Birdnesting can also lessen the integrity of the weld. You’d know you’re birdnesting when the wires get tangled and stop during the feed. 

Use appropriate roll tension to avoid the wire from getting flattened and tangled. We recommend you use U-groove or knurled V drive rolls. This will compress the wire with ease to prevent birdnesting. 

Prevent Porosity

Clean the metals first before you begin. This will ensure that no gas gets trapped in the weld. Trapped gas can cause porosity and reduces the cohesion of the weld. So get rid of contaminants like rust, grease, oil, paint, dirt, and moisture.

You might also want to pay attention to your travel angle. Too much push or pull can also lead to porosity. 

Apply the Right Amount of Penetration

Applying proper heat input can also improve your flux core welding strength. Too much heat can lead to excessive penetration. You don’t want to weld through the base metal. So lower your voltage range as well as your wire feed speed. You might also want to increase your travel speed. 

If you need to increase the penetration, you must reduce the travel speed. You should choose a high voltage range and a faster wire feed speed.  

welder using a flux electrode

Flux Core Welding Strength With Different Metals

Flux core welding is versatile enough to work with various materials. That’s the reason why many shop and farm owners prefer this method. It can easily join metals like stainless steel, high-nickel alloys, low-alloy steels, and carbon steel. 

The penetration capabilities of flux core welding also make it efficient even on galvanized steel. You don’t have to get rid of the zinc layer to begin welding. 

If there’s one metal that flux core welding performs poorly, it would be aluminum. The reason for that is because:

  • Tested aluminum fluxes are very corrosive and absorb water from the air. These traits make low-quality welds.
  • Flux core welding uses concentrated heat. Aluminum absorbs heat fast which could lead to burn-through.
  • The fluid nature of aluminum creates too much spatter. It makes the welds weak and less appealing.     


We’ve learned that flux core welding produces strong welds. You can use it in various circumstances and conditions. Likewise, it has some characteristics that make it better than MIG welding. First is the wire build. The other one is its penetration capabilities. 

We discovered, too that flux core isn’t choosy when it comes to the kind of metals it can combine. 

Lastly, while flux core welding is strong in and of itself, you can further improve and enhance its strength. You have to follow a few simple steps.