The process of flux-cored arc welding (FCAW) was first developed back in the 1950s. Back then, it was created as an alternative to manual metal arc (MMA) welding. FCAW made welding easier due to a continuously fed wire electrode. The wire is constantly fed due to a constant-voltage welding power supply plus other equipment similar to what is used for metal active gas (MAG) welding.
This technique is popular across construction sites, auto garages, and many shops because of its high welding speed and portability. Welders can also work quickly and with different types of materials. You’ll find this technique used in bridge construction, erecting structural steel, repairing heavy equipment, and various smaller tasks that need a quick but effective weld.
This process can be completed by using a MIG welder. However, you may have to change the rollers or adjust the contact tip to accommodate the thicker wire electrode. For larger projects in the industry, you might find yourself using machines explicitly built for flux-core arc welding. The biggest difference between these machines and traditional Mig welders is that the FCAW machines offer high current and voltage settings for welding thicker pieces of metal.
Ready to start learning more about FCAW welding?
How Flux-Cored Arc Welding Works
As the name implies, flux-cored arc welding involves the use of a welding electrode with a flux core. Big surprise, right?
Flux-cored arc welding uses the heat generated from an electric arc to fuse metal in the weld joint area. The arc melts the wire to the base metal to form the weld joint. The electrode forms a slag that covers and protects the molten metal being welded.
Since the flux helps shield the weld, you can use this process outside—even in windy conditions! There’s no need to use an external shielding gas, so there are many opportunities to practice this welding technique. With that being said, if you want to use an external shielding gas, you can.
The other way flux-cored arc welding can be completed is by using a shielding gas provided by an external source. This is known among the welding industry as dual shield welding. This technique uses both the flux and external shieldings like carbon dioxide or argon carbon dioxide blends to protect the weld. You’ll find this technique used in many metal shops as it is stronger and more consistent welds. Typically, external shielding gas combinations for dual shield welding will be a 70% argon and 25% carbon dioxide mix. Unlike straight-up FCAW, you do not want to use the dual shield method in windy conditions as the airflow can disrupt the shielding gas and weaken the weld.
Both of the techniques we just covered will leave behind slag created by the flux. It doesn’t matter your skill level or years of experience—there’s no escaping slag being thrown everywhere when working with flux. Not to worry though, this is easy to remove with a wire brush, grinder, or chipper.
When practicing this technique, there are a lot of variables that can impact the process. These include:
- The speed of the wire being fed
- Arc voltage
- Electrode extension
- Travel speed and angle
- Electrode angles and wire types
- Shielding gas composition
- Contact tip to work distance
This technique performs well with stainless steel, cast iron, most carbon steels, and hard-facing/surfacing alloys.
One last thing to note here about how this process works. The flux core gets extremely bright and can flash burn your skin. An easy way to prevent this is by making sure you wear long sleeves or a welding shirt. Welding gloves with long cuffs to protect the wrist are an essential item in your safety equipment checklist.
Advantages Of Flux-cored Arc Welding
Compared to MMA and MAG welding, the flux-cored arc technique offers a lot of advantages. This is why it’s such a popular technique and preferred method for a lot of great welders working in professional settings. Learning to excel at flux-cored arc welding is something every welder should pursue and practice regularly.
Besides portability and outdoor use, this technique makes it easier to join thicker pieces of metal together. Not only that, it offers a lot more flexibility with alloy compositions than MAG welding does. Improved arc stability and a higher wire deposition rate make high-speed applications possible and still produce quality welds every time.
This technique is also one that welders of all levels can learn to do. Many people refer to it as an “all position” skill to have since it’s one of the first most welders learn. It requires less skill than MMA or MAG. Another advantage of this technique is you don’t need to spend as much time precleaning the metal.
Limitations and Things To Consider with Flux-Cored Arc Welding
While there are many advantages to flux-cored arc welding, there are some limitations to consider as well. One difficulty with this technique is visibility. Flux-cored arc welding produces noxious smoke, making it harder to see the weld pool in some conditions. If these gases cannot escape before the weld solidifies, porosity can be a problem.
While this technique is good for joining thicker pieces of metal together, it doesn’t perform as well on thinner pieces of metal. As a general rule of thumb, you should avoid this type of welding on materials thinner than 20 gauge.
Equipment Needed For FCAW Welding
Every welding project is going to be different and may require some or all of the following tools. This equipment list should cover everything you need to complete your welding project using the FCAW technique.
Pro tip – if you enrol in the Welder 101 course, you can get access to equipment discounts from some of the best companies in the industry!
- Safety glasses
- A welding mask
- Ear protection
- Work gloves
- Long sleeve clothing
- Wire brush
- Tape measure
How To Flux-core Arc Weld
Once you’ve got your equipment and tools ready, you can start practicing this technique. Here’s a quick run-through of how to perform this type of weld.
Step 1: Clean Your Metal
Yes, you can get away with welding dirty metal with this technique, but, if you can spend some time cleaning your material beforehand, do it. A simple wire brush or grinder is all it takes to remove contaminants like rust and paint.
A quick pro tip is to use a wire brush on a grinder to speed up the process and get the best results. If you do plan to use a grinder, make sure the welding material is secured before you start.
Step 2: Cut Your Materials and Setup Your Work Piece
Once you’ve got the metal all cleaned up, you can begin to cut the metal to size. Next, use some magnets to set up your workpiece and get it ready to make a couple of tack welds.
In larger shops and factories that do mass production, you’d likely find the operators using jigs that can easily set the pieces into place. For DIY jobs, though, and smaller shops, magnets work great.
Step 3: Get Your Welder Ready
Now that you’ve got all of your materials ready, it’s time to turn the welder on and get everything set up. Depending on the size and type of the materials you’re using, you’ll need to adjust the settings on your equipment.
The wire speed and voltage will vary depending on the gauge of the metal being used. A thicker metal requires a higher voltage and wire speed to make quality welds.
If you’re unsure you have the proper settings, take some time to do some practice welds first. You can check manufacturer recommendations or access the materials available inside the Welder 101 course for more advice to ensure your equipment is being used correctly.
Step 4: Tack-Weld Your Work Piece
Once you’re confident in your machine’s setting, do a couple of tack welds on each end of the joint you’re welding. This will help hold the materials in place as you complete the rest of the weld.
Make sure to tack your welds exactly where the two pieces of metal join. If they get a little too far to one side or the other, the lack of fusion can result in the materials not joining together correctly.
Step 5: Bead Weld the Remaining Area
After you’ve completed your tack welds, you can fill in the rest of the joint with bead welds.
Pay extra attention to your torch angle and travel speed. The key to good welds is consistency. Keep your travel speed fairly fast, but maintain a constant pace as you work. This speed and consistency will ensure that you get the proper penetration on your weld.
Step 6: Remove the Slag
Now that you’ve completed your welds and everything is joined together, it’s time to clean up your workpiece. As I mentioned before, there’s going to be slag and splatter leftover from the flux. Unfortunately, you can’t avoid this. What you can do, though, is use a wire brush or chipping hammer to remove as much of it as you can.
Once finished with these hand tools, you can use a grinder to remove the outer layers of the weld until everything is flush and clean. If you find any defects like holes or cracks, you’ll need to reweld the area to correct this and repeat the clean-up process.
Step 7: Clean Up Your Tools and Work Area
If all the slag is removed and you’re happy with how the weld looks, you can start to pack up your tools and clean up your workspace.
It goes without saying that a clean workspace is a safe workspace, so don’t be lazy and properly clean up after each job. Materials left lying around are not only irritating and pose tripping hazards etc, but they are also fire hazards. Welding produces extreme heat and sparks, unclean workspaces can be catastrophic.
Master The Art Of Flux-cored Arc Welding Today!
Learning how to safely and adequately practice flux-cored arc welding is a skill every welding master has developed. You can develop this skill from the comfort of home by enrolling in the Welder 101 course.
This program distills 30 plus years of welding experience into a comprehensive and on-demand welding course. Every welder makes mistakes when they start out on their first welding projects. With Welder 101, and the easy-to-follow video tutorials, you can make fewer mistakes and start working towards a new career or bigger, more exciting personal projects.
Whether you’re just starting out or simply want a quick refresher, Welder 101 is perfect for all skill levels. Welding is a skill you can continually develop and improve. Even master welders need to spend time studying different techniques and practicing their craft. When you enroll in the program, you receive lifetime access to all current and future content so you can continue your progress at any time. The Welder 101 course includes over 50 tutorial videos to help you get started. New content is also being added regularly, so you’ll always have something new to learn about.
Besides just the course materials, you’ll also get access to our private Facebook community. Inside this group, you can interact with other students and mentors and participate in different welding challenges and contests.
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