Flux Core Arc Welding (FCAW) is a fast, flexible, mobile method of welding. One added benefit – the process produces its own shielding gas, making it good in windy conditions. However, there are some challenges. To aid you through the process, leading fabricator LeJeune Steel Company (LSC), would like to share some helpful Flux Core Welding tips.
FCAW requires a Direct Current (DC) power supply and you should check the settings. Generally the polarity is D/C electrode (+) positive. The handle is the positive side, meaning the electricity flows from the metal to the welding handle. This generates high, steady, heat to the electrode and a stable arc.
Proper Tension Reduces Drama
Before welding, check the contact tip, the roller speed, and set the wire tension. FCAW uses a continuous wire feed over rollers. Too much tension crushes the electrode in the rollers. Wire speed controls wire flow to the weld joint. Changing wire speed changes the amperage. The faster and harder the wire contacts the joint, the higher the amps and heat.
Down to the Wire
FCAW uses a consumable hollow wire, lightly coated in metal. The middle is filled with flux and metal powder. DC power charges the electrode. When it meets the metal, it produces enough heat to melt this mixture and the metal, which produces a flux shielding gas and slag that protect the weld pool from contamination. So there is quite a bit of emphasis on making sure the wire feeds properly.
- Bird-nesting happens when the wires get tangled. FCAW wire is softer than MIG wire, so use knurled V or U-groove drive rolls in your feeder.
- Burn-back happens when you touch the tip of the electrode to the weld pool and the hollow middle fuses shut. Generally happens when the wire feed is too slow or the gun is too close to the weld pool. Keep the contact tip about 1 ¼ inch away from the material.
- Make sure to keep the proper electrode extension, otherwise called “stick-out.” Experts say that means no more than 1¼ inches past the contact tip.
Staying in the Flow
Decide what type of transfer or flux flow you need. That means checking the voltage setting, wire speed and what gas you’re using (if you choose dual-shield welding). There are two types of transfer, Globular and Spray.
Often used on thinner metals. Heat is transferred through the electrode. When hot, globs of metal drip off the electrode into the weld joint. Makes a popping sound during welding.
When hot the electrode actually sprays filler metal into the joint. Makes a deep, fast crackling sound during the welding.
Unlike the 5-8 pounds of welds you get from MIG, FCAW allows you to speed through more than 25 pounds per setting. That will be great for your production numbers.
Setting up your welder is best done on a piece of scrap metal close to the thickness that you are planning to weld. If your set-up is accurate you don’t need a lot of skill to use the FCAW method. Just try to remember these helpful Flux Core Welding Tips and let’s get cooking with our own gas.
For more than 70 years, LeJeune Steel has been an industry leader in steel fabrication. Since 1944, we have grown to become one of the largest structural steel fabricators in the Midwest, with more than 40,000 tons of steel fabricated annually by our shops in Minnesota and Wisconsin.