New developments in modern pipe welding

2022-05-28 21:15:31 By : Ms. Erin Tan

The Pipeweld Orbiter from ESAB Welding & Cutting Products is a mechanized welding system that is designed to reduce the cost per joint on pipeline projects involving tie-ins and special sections, such as road and river crossings.

Technological change has reached a furious pace in some parts of the manufacturing world. In other places, some traditional means of fabricating still hold out.

The reasons are familiar. Acquiring new technology may be viewed as cost-prohibitive for some companies. Others simply believe if the process is not broken, why bother to fix it.

Competitive realities are independent of checking accounts and inefficient fabricating practices, however. They have a tendency to hit companies in the face if they aren’t paying attention to the world around them.

That’s particularly true in pipe welding. The combination of experienced welders and the belief in tried-and-true methods of joining pipes has created an environment that hasn’t been quick to change. But if recent technology introductions made at the FABTECH® show in Chicago last November are any indication, pipe welders may be put in the position where they will have to seriously consider new welding technologies.

The way that mainline pipe welding—the welding of long, straight sections of pipe that cross the countryside—is done in North America is fairly straightforward. Two sections of similarly sized pipes are brought together, and a pneumatic or hydraulic machine, typically on the inside, is used to clamp the two sections together to facilitate the welding. When connected, the pipes are J-beveled about 5 degrees to accommodate the on-site welding. (The pipes traditionally leave the pipe mill with a 30-degree bevel on their ends.) An external wire-fed welding bug is then used to lay quick and consistent beads all the way through the final pass.

This approach works well until you are required to join special sections of the pipe, which may have to clear a road or a river crossing, for example. These special sections are fabricated to the required length and then tied in to the main line that stops and starts again on either side of the crossing. You simply can’t use the internal clamping technology for these types of applications because if the brakes on these units were to fail, these large devices, some weighing up to 1,000 lbs., would come screaming down the pipe like a torpedo. In fact, these internal clamps are not used on inclines of more than 22.5 degrees. There’s no getting around the law of gravity.

Gordon Eadie, global pipeline segment manager, ESAB Welding & Cutting Products, said that in these situations, manual welding is needed to complete the job. Welders not only have to be skilled enough to work in various vertical welding positions, but also at odd angles, like 30 or 60 degrees. Needless to say, that leaves some exasperated companies looking for some automation help. They have gotten a taste of what automated welding has done for mainline welding, so why wouldn’t they want something for these not-so-straight segments?

That led ESAB to develop the Pipeweld Orbiter, which consists of a lightweight bug and a fast-fit band that clamps on pipe with diameters greater than 8 in. (Pipe wall thickness, particularly for smaller-diameter pipe, will help to determine if mechanized welding makes sense for this type of application. For example, a welder using cellulosic electrodes for the root and hot passes on an 8-in.-diameter pipe with a wall thickness of 0.25 in. likely could finish off the fill and cap passes easily enough without the need for mechanized follow-up.) The bug contains the torch, drive mechanism, controls, wire spool holder, wire feed mechanism, cables, and hoses. It is designed to work with any constant-voltage welding power source that can provide sufficient output for the wire selected. For larger-diameter pipes, perhaps 16 in. or more, two bugs can be used at the same time on both sides to speed up the welding process.

“Flux-cored wire lends itself perfectly to this,” Eadie said. “It’s great for the special sections, the crossings, or tie-in welds where they’re joining the long sections of pipe where they can’t utilize the internal clamp.”

When flux-cored wire is used for these pipeline welds, the flux freezes up quickly without affecting the weld pool fluidity underneath and the expected penetration profile. Because of those performance characteristics, flux-cored welding is the technology of choice for a majority of the pipeline work done outside of North America, Eadie said. In some parts of the world, the filling and capping with cellulosic electrodes is now becoming almost forbidden.

The PIPEFAB welding system from Lincoln Electric is a power source designed specifically for the pipe and vessel fabrication market.

Some are slow to accept change, however. That’s why consumables have been tailored for the type of pipeline welding application that one is likely to encounter in the U.S. Pipeweld cellulosic electrodes can be used for completing the root and hot pass, while the Pipeweld Orbiter automates the fill and cap passes using flux-cored electrodes. In another procedure, Pipeweld DH low-hydrogen electrodes can be used for the first fill pass, and the Pipeweld Orbiter can finish up the remaining passes.

Eadie said that manual welders would find it hard to keep up with the mechanized bug, especially with the uphill FCAW being able to deposit up to 9 lbs. of filler metal per hour. He added that the process is much more consistent than those that use shielded metal arc welding or solid-wire, narrow gap-procedures.

Eadie shared a case where a company had 200 miles of pipe to weld in Europe and was awarded an additional contract for another 50 miles on the same pipeline. What should have been a celebratory moment quickly turned into a dilemma. They had enough mechanized devices for the straight, mainline pipe welding they had planned for, but they couldn’t justify the cost for more machines for the additional 50-mile project. (Most of the machines designed for these narrow-gap pipeline weld applications are rented from equipment rental companies.)

“They were using this Pipeweld Orbiter technology on the tie-ins and the crossings because there were sections within that original 200 miles where they couldn’t use the traditional clamp,” Eadie said. “They very quickly learned that, if they manned this project correctly, they could in fact compete timewise with the number of welds they could produce with an alleged faster process.”

While using the Pipeweld Orbiter for all the connections on the 50-mile project, the welders also learned that they didn’t need to rebevel the pipe ends. This meant that they didn’t have to employ a cleanup crew to collect the metal shavings and deal with the cutting fluid.

When the pipeline welding was complete, the company took a critical look at the costs of the different welding approaches. They learned that they were getting about 60 joints per day on 48-in.-diameter, 0.75-in.-wall pipe using the traditional narrow-gap process with five welding crews (10 welders). With the flux-cored process, the company still got 60 joints per day, but they had six crews (12 welders) working the process. Even with the extra crew, however, the company found that the overall cost per joint using the Pipeweld Orbiter was 40% less than using the mechanized equipment for the narrow-gap process, when the mobilization and machining costs were included. The company also retained the equipment at the end of the job instead of returning it to the rental company.

Eadie added that this type of pipe welding technology doesn’t require a lot of training. Because of easy-to-use controls and the consistent production from the vertical-up flux-cored process, competent operators can be trained in a day.

“We’ve got a couple of projects that are welding in Texas with flux-cored,” Eadie said. “It’s quite new for guys there … but we’re seeing quite a bit of interest.”

New technology introductions from welding companies Lincoln Electric and ESAB promise to alter the way pipe is welded. Getty Images

Welders doing this type of pipe work share many of the same pressures as their peers in other areas of metal fabricating, one of which is doing more with less. Companies are interested in increasing productivity so that they can complete projects sooner and move on to the next money-making opportunity. Meanwhile, quality has to be maintained because in this type of work, failure could be disastrous. For example, a chemical leak is not something that anyone wants to deal with.

Against these ever-increasing expectations, pipe and pressure vessel shops and mechanical contractors are having to deal with the struggles of finding the right operators and welders for their openings. This is particularly true when it comes to those openings for which high-level skills, such as gas tungsten arc welding (GTAW), are needed.

In short, any tools that can help pipe welders do their jobs more efficiently without sacrificing quality are likely to be appreciated greatly. That led Lincoln Electric to develop its PIPEFAB™ welding system.

“We started with existing technologies that were already serving this space and delivering the welding performance that they needed, but maybe not the experience that they required from an ease-of-use perspective,” said Lincoln Electric’s Bruce Chantry, director, advanced technology products. “So we spent a lot of time in these pipe and vessel shops listening to customers and observing them in their operations to understand how they use the tools in their day-to-day world.”

That welding reality in a pipe and pressure vessel shop is going to be completely different than life in the welding department of a large OEM like John Deere or Caterpillar, where someone is likely gas metal arc welding (GMAW) with the same wire size and gas combination for most of a work shift. Pipe welders in a shop are constantly switching between shielded metal arc welding, flux-cored arc welding, GTAW, and GMAW.

To give welders that ability to walk up to a power source, leave everything connected, and choose the process needed for the job with a push of a button, Lincoln Electric engineers designed the PIPEFAB system so that all process outputs are electrically isolated. No disconnections and reconnections are needed when the process is changed. The company calls it the Ready-to-Run™ design.

That helps to address the need for increased productivity, but what about the concerns about the lack of welding experience and knowledge in the pipe welding field? That’s where the new visual display comes into play.

“By going to a nice high-visibility, industrial-grade, 7-in. screen, we now can use this display as a means to exchange information with the operators to try and make their lives easier,” Chantry said.

Historically, the user interfaces on welding power sources were pretty limited. There might have been some labels on a nameplate with some LED lights that told the welder what process had been chosen, but overall they were fairly rudimentary.

Instead of theorizing what pipe welders might want, Lincoln Electric used the expertise of a company that specializes in user interface and design to help with the PIPEFAB system development. They did extensive customer research with pipe welders, learning what they liked and didn’t like. They researched and benchmarked information centers associated with products like the Ford F-150 and a John Deere tractor. That led to several different concepts for screen layouts, hardware forms, and placement of buttons and knobs. Further welder feedback helped to get the final user interface to where it needed to be.

“This focus allowed us to make the user experience incredibly intuitive and educational,” Chantry said. “As an example, if somebody were to have an error code appear for some reason, rather than the error code just popping up, the welder is now able to learn what the error is and maybe even some potential solutions to solve it. We can now start to impart knowledge to them on how to fix problems.”

The user interface was an important development for the PIPEFAB product because in many instances it might be the deciding factor for companies looking to buy new pipe welding equipment, Chantry added. While experienced welders might like Lincoln Electric welding technology better than other power sources in the marketplace, shop managers or equipment purchasers may lean toward the most user-friendly machines, given that they are likely to have less experienced welders working for them with the retirement of the baby boomers.

Lincoln Electric also has improved the welding performance of its new pipe welding power source, according to Chantry. The company’s patented Surface Tension Transfer® process, a modified short-circuit GMAW, has been fine-tuned to deliver faster travel speeds and more arc stability. In fact, at one time pipe welders had to use shorter cable lengths or sensing leads to ensure a stable arc during the joining process. That doesn’t have to be the case anymore with the introduction of CableView™ technology, Chantry said.

This patented feature continually monitors cable inductance and adjusts the waveform to maintain consistent arc performance with long or coiled cables up to 65 feet (19.81 m). Welders don’t have to worry about the additional wires that were present when sensing leads were needed. Also, the CableView technology notifies the welder if inductance is outside of performance thresholds.

“It doesn’t matter if a welder is working with a 15-ft. [4.57-m] cable in ideal conditions or a 50-ft. [15.24-m] cable in not-so-ideal conditions. The welder doesn’t have to touch a thing to ensure arc stability,” Chantry said.

The PIPEFAB system also is designed to deliver pulse welding characteristics tailored to pipe welding. Using Lincoln Electric’s Waveform Control Technology®, the Smart Pulse™ feature monitors the machine settings and tailors the pulse for each pipe welding application, such as out-of-position and 1G pipe welding.

Chantry said that this pipe welding technology was developed for what pipe welders are doing today and for other possibilities down the road, perhaps with newer, not yet identified materials. Another thing product developers kept in mind was the need for Industry 4.0 connectivity. While many manufacturers have yet to embrace the full potential of what this type of digital manufacturing management can do for productivity and quality, they have the comfort in knowing that the PIPEFAB system will be able to be a part of such an interconnected environment.

“Customers can connect this up with the Ethernet to their network and take advantage of our existing data solutions when the product is taken right out of the box. They can manage and oversee their welding operations from anywhere in the world,” Chantry said.

See More by Dan Davis

Dan Davis is editor-in-chief of The FABRICATOR, the industry's most widely circulated metal fabricating and forming magazine, and its sister publications, STAMPING Journal, The Tube & Pipe Journal, and The Welder. He has been with the publications since April 2002.

Read more from this issue

Find The FABRICATOR on Facebook

Find The FABRICATOR on Twitter

The FABRICATOR is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1970.

Easily access valuable industry resources now with full access to the digital edition of The FABRICATOR.

Easily access valuable industry resources now with full access to the digital edition of The WELDER.

Easily access valuable industry resources now with full access to the digital edition of The Tube & Pipe Journal.

Enjoy full access to the digital edition of STAMPING Journal, which serves the metal stamping market with the latest technology advancements, best practices, and industry news.

Easily access valuable industry resources now with full access to the digital edition of The Fabricator en Español.

© 2022 FMA Communications, Inc. All rights reserved.

Not yet registered? Sign up