Fortuitous Flux

Productivity benefits of all-position, flux-cored products

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In a perfect world, every weld would be made in position, on clean material and require no post-weld cleaning. Unfortunately, that’s not reality. Depending on the industry and application, a welder is going to have to perform some out-of-position welds to bring the materials together and create a sound weld joint. Stick, short-circuit MIG and pulsed MIG welding are options that can accomplish out-of-position operations, but they also come at the cost of efficiency and productivity.

With these welding processes, the increased time spent working at slower travel speeds, controlling the necessary deposition rates and managing any pre- and post-welding activities all adds up when welding out of position because these concerns aren’t just limited to carbon-based steels.

With self-shielded, flux-cored products, welders can maintain the productivity benefits of a wire-fed process while being able to weld out in the field.

The switch to all-position, flux-cored wire enhances efficiency and helps improve throughput due to faster travel speeds that are achievable, increased penetration and higher deposition rates – all of which minimize rework and keep uptime at a maximum.

Flux-cored basics

Before looking at how flux-cored wire can positively impact out-of-position welding, it’s probably worth a quick reminder of what it is and how it works. Flux-cored wire is a tubular product where the core is filled with flux powder and a mix of chemicals that protect the weld from contaminants. The flux also helps obtain desired mechanical properties such as impact toughness and tensile strength.

Additionally, the flux-core wire can be self-shielded (FCAW-S) or gas-shielded (FCAW-G). In this case, the flux in self-shielded wire creates the shielding gas, making it an ideal selection for outdoor applications. The gas-shielded, option still requires the use of a gas mix during the welding process and is best used indoors. Lastly, flux-cored wire is available for both in-position and out-of-position welding, so it’s important to use the type that matches the task.

With pulsed MIG, the current is pulsing during the welding process. The power source alternates between high peak current to melt the metal and a lower background current to maintain the arc. Because of this, a specific gas mix is required to help maintain the transitional current and control the spray transfer as the weld is being made. That mix is commonly seen at 90 percent argon to 10 percent CO2, and industry standard requires a minimum argon content of around 80 percent to achieve a spray transfer mode.

In most FCAW-G applications, a 75 percent CO2 to 25 percent argon mix or a 100 percent CO2 mix are commonly used within the industry. Some gas-shielded wire is gas-specific, but regardless of the gas mix, all-position, flux-cored wire will help maintain control of the weld pool and achieve acceptable weld bead appearance. Because FCAW-G products utilize simple and common gas mixes, there is no extra money spent for proprietary mixes or additional time swapping gases.

Out-of-position welds

When faced with challenging positions, the ante is upped for a welder who needs to maintain control during the process and work effectively against gravity in the weld pool. If they’re not welding in the flat position, the weld pool is likely going to sag or drip, which can lead to inconsistent weld profiles and compromised weld quality.

With stick welding, in particular, the need to change the electrode results in an arc stop. This requires the welder to clean and feather the crater area to begin welding again if they want to maintain a consistent weld profile. If it’s a long weld joint, there will likely be multiple arc stops, which adds time to the process and increases the likelihood of slag inclusions if the welds aren’t properly cleaned.

All-position, flux-cored wire helps maintain control of the weld pool and achieve acceptable weld bead appearance.

Welders who turn to pulsed MIG for out-of-position welds start to improve the efficiency issues experienced with stick welding. However, they need to have the proper expertise and experience to make sound acceptable welds. Adjustments to wire feed speed and travel speed are critical for successful out-of-position welding and are typically on the lower range of the operating window.

On top of that, the weaving technique required for out-of-position welding requires expert handling of the weld gun to ensure proper penetration and fusing into both walls of the workpiece and the root of the weld. This becomes a very precise and physically demanding operation. Maintaining that stability needed in vertical and overhead positions is challenging, and again, gravity can negatively affect the behavior of the weld pool.

Flux-cored wire allows a welder to run a stringer bead without needing to manipulate the gun and it achieves the consistency needed for high-quality welds. Other advantages of flux-cored wire welding are higher deposition rates due to the higher wire feed speeds achievable, which lead to increased travel speed and increased weldability from the ease of use and lack of manipulation required. This all helps increase throughput and overall productivity.

Reduced prep work

Base metal prep is typically a crucial step prior to welding regardless of the process. Contaminants like dirt, grease, oil or rust are often present on the base material and can negatively impact the quality of the weld. Additionally, mill scale, a flaky, oxidized layer sometimes present on the base metal, can cause poor wetting and increase the chances of inclusions, which hinder the formation of a strong, clean weld. With certain weld processes, it’s imperative to have a clean base to facilitate better fusion between the filler metal and the base material, which results in sound welds with fewer discontinuities.

Watch the video to learn about the differences between flux-cored welding and MIG welding.

Because of the deoxidizers and shielding elements present in flux-cored wire, in addition to being able to weld at higher amperages out of position, the welder can burn through most surface contaminants and maintain acceptable penetration and internal weld quality. That allowance means they don’t have to clean the base material before starting, which saves time.

Approaching out-of-position welding from processes like stick or pulsed MIG no doubt gets the job done, but when shop productivity is at a premium, finding high-performing alternatives is a must. Switching to flux-cored products for out-of-position welding provides consistent and high throughput welds without the pain points typically associated with the traditional processes. The adage goes, “work smarter, not harder,” and flux-cored consumables not only provide the smarts but the coveted productivity, as well – a must for any welder or business owner.

Hobart

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