Common welding issues can be solved by making better filler metal choices. Flux-cored, metal-cored or solid wire filler metals offer benefits in applications where each is best suited. Because of the way that cored wire is produced – by adding metal powders and other elements to a wire sheath – manufacturers can tailor the additive chemistries and sheath composition for a wide variety of steel, stainless steel and nickel-alloy welding applications.
Knowing when it’s most advantageous to use cored wire can help increase productivity and save money by allowing more efficient welding with higher deposition rates, all-position welding capabilities (for flux-cored), reduced cleanup (especially for metal-cored) and better quality.
One area where flux-cored wire could help lessen defects is in applications where using a smaller diameter solid wire is causing a lack of penetration in the sidewall of the joint because the arc cone is not wide enough.
“A perfect example is people who are having sidewall fusion problems on a larger joint in structural steel welds,” says Bob Gulas, business product manager – cored wire, ESAB Welding & Cutting Products. “If they’re in a V-groove and running 0.045-in. wire, they should consider a larger diameter flux-cored wire. For materials 1/2 in. or thicker, they can step up to 1/16-in.-dia. wire, which will create a wider weld bead. Bumping up to a larger diameter will input more heat and provide a bit more drive. Users can probably fill the joint in a single pass versus the two passes needed with 0.045-in. wire. A higher deposition rate means fewer passes so the work gets done faster with higher quality and lower total costs.”
However, the welders themselves can be resistant to changing wire; some may believe they are being tasked with working harder. These welders might have the perspective that by switching wire, their supervisor is trying to increase their arc-on time or increase their throughput – even though they’ve been successful with 0.045-in. for quite a while.
“To overcome this perception, we have to show welders the advantages,” Gulas says. “The deposition is going to be higher because of the larger diameter of the wire, and in turn, the welds are going to be more sound with fewer defects. By going from a 0.035-in. or 0.045-in. to 1/16-in. wire, the cost per pound is going to be lower as well. But the perception in the weld shop is that changing it up means management is just trying to get the welders to work faster and harder.
“There is also the shop supervisor or accountant who’s trying to save on the front end,” he adds. “But, the problem with that mindset is that if you’ve been welding with the same wire for a long time, chances are you’ve been leaving money on the table – which is especially true with the bigger shops (see Table 1). So that is an opportunity to understand that you are probably going to have to change your procedure, but the benefits from a cost standpoint are worth it.”
To help shops understand the productivity and benefits of wire diameter choice, Gulas suggests ESAB’s Quick Weld Productivity Analyzer. By entering welding variables and using drop down menus for common solid and cored wire, users can calculate deposition rate, travel speed, cycle, cost per foot of weld and more.
Another area where flux-cored wire can be a big benefit is in situations where the welder doesn’t have a lot of experience. With a solid wire, the welder’s technique and experience play a bigger role: With solid wire, they’re using different types of arc transfers, such as pulsed spray or short circuit transfer for out-of-position welding, which can be difficult for an inexperienced welder to achieve. Flux-cored wire, on the other hand, allows inexperienced welders to qualify their welds faster while they’re still in the process of learning and perfecting their trade.
Another solution for less experienced welders is flux-cored wire using a thinner metal sheath. Concentrating the welding current in a smaller area (the thinner sheath) gives welders a wider operating range.
“Many times with a solid wire, or even a metal-cored wire, the welder has to make adjustments in the parameters to achieve the weldability of their joints – and that requires experience,” Gulas says. “With a flux-cored wire with a thin sheath, whether the welder is traveling at a slower speed or the heat input is lower, they are still able to control that puddle, control the weld and go out of position. With a solid or metal-cored wire, the only way the welder is going to do that is with a process change.”
Throughout his years at ESAB, Gulas has had several occasions where changing the weld procedure to a cored wire resulted in a major success. Because of the savings in the long run, the extra time and effort required for the change in the specification was well worth it.
“I can offer several examples where I’ve gone into a fabrication shop that used solid wire about 80 percent of the time, but because of high turnover rates, which results in hiring less experienced welders, they’ve been forced to consider other options,” Gulas says. “Committing to a change in wire ultimately depends on the project and how their procedures are written, but that’s where we can step in and show them that they can save time and money by spending the time and money to change their procedure. Welders will be able to complete jobs in a timelier manner with less weld defects, and, in turn, they can increase throughput in the shop.”
No matter the material, application or environment, sometimes a shop has to drill down into the exact problems they’re encountering. This often reveals the need to look at more specific products, such as wire with low hydrogen levels or non-copper coated wire to help with issues with copper flakes building up in the wire feeding equipment.
For applications requiring low hydrogen levels, such as welding on high-strength steel, filler metal manufacturers can formulate flux-cored wires with hydrogen levels as low as 4 ml per 100 g of weldment, which helps reduce the risk of hydrogen cracking. To prevent moisture issues, these wires are vacuum packed. Additionally, ESAB offers a seamless low-hydrogen wire. Sealed seams mean no chance of picking up moisture so the wire can retain its low-hydrogen properties, another benefit for inexperienced welders.
The right class
Regardless of the type of filler metal, the decision must always take quality into consideration. Just because a wire has an AWS classification, doesn’t mean all wires of that classification perform the same.
“Manufacturers of different wires can say they are all E71T-1 wires, which is probably the most common wire for welding structural steel in all-position,” Gulas says, “but in the end, welders will struggle if they’ve been given lower quality E71T-1 wire. The welder is left with a narrow operating range and must have all their parameters fine tuned – the voltage, amperage, stickout and travel speed as well as the welder’s technique.
“Higher quality wires on the market are much more forgiving or what I call ‘operator friendly,’” he continues. “Overall, they have a wider parameter window. As an example, the welder may be able to get away with less than perfect manipulation because the slag system is going to freeze and support the puddle better, which makes it easier for the welder to direct the puddle. They may be more forgiving with stickout. They may provide lower spatter levels and offer easier slag removal. The broad operating range works with attributes from one welder to another. Regardless of their skill level, they can perform the weld, even out of position, because the operating range for that wire gives them that flexibility.”
In the end, the time and effort required to switch to a new filler metal is minimal when compared to the long-term benefits. It’s key, though, to seek out products that were formulated and based on customer feedback. Purchasing from a company that has thoughtfully considered how welders of all experience levels actually operate is always going to be the best choice.