Quality Connections: Welders Play Crucial Role in Pipeline Integrity
As oil prices have plummeted and the pipeline industry becomes more conservative, companies put increased focus on efficiency to ensure to success. Out on the right of way, that means efficiency and quality must go hand in hand. For welders, those hands clutch torches and operate the controls of automated welding systems that create the critical connections from one end of a pipeline spread to the other.
The pipeline welding field faces a number of challenges to maintain efficiency and integrity on the jobsite, such as the skill of welders, quality of the filler metals, using the correct welding procedure and being able to quickly troubleshoot issues that occur in the construction process.
To make the welder’s job easier, equipment manufacturers and suppliers are continuously developing new welding machines, better filler metals and improving processes to “simplify the variables that occur during welding,” says Tyler Edwards, pipeline technical sales specialist for the ITW Welding global onshore pipeline division. These variables can include higher strength pipe, a lack of qualified welders or introducing new welding machines that are more efficient and easier to use.
There are two main types of welding seen on pipeline projects in North America, Edwards says, the first being manual “stick” welding, or shielded metal arc welding (SMAW), and automatic welding, referred to as a “bug.”
“With automatic welding, typically there will be a bead and hot pass welded with the stick process,” Edwards adds, “then the rest of the weld joint will use the automatic system.”
In addition to SMAW, there is also flux-cored arc welding (FCAW) and gas metal arc welding (GMAW), which refer to the filler metal and process used to join the pipe ends together, says Paul Spielbauer, welding engineering manager for CRC-Evans, which primarily uses FCAW and GMAW for its automated welding systems.
“Mechanization provides a consistency in quality and production that can be difficult to match with other manual or semi-automatic processes,” he says.
Spielbauer adds that having an experienced and properly trained work crew, high quality equipment and consumables, proper setup of work crews and the right of way and good communication between inspection and welding are some of the keys to a successful project.
Edwards agrees, noting that pipeline jobsites can be filled with unknowns, including issues related to workers, equipment and the weather.
“From a welder not being consistent enough to the machines that need to be repaired or replaced,” Edwards says. “The filler metals need to be able to meet the specified mechanical and welding requirements. The welders and operators need to follow the welding procedure that has been approved so that bad welds are repaired. The weather is a factor also, the weld joint needs to be preheated and sometimes post-heated so that the welds do not crack from hydrogen or cold climates.”
Manual vs. Automated
There are benefits and drawbacks to each of the major types of pipeline welding practices. Manual welding is easier to deploy but more difficult to maintain consistency. Automated systems provide repeatability but require higher capital expense to deploy.
“Handheld or manual welding is much easier for a single person to operate,” Edwards says. “There is less equipment involved so it’s cheaper to purchase and operate. A drawback is that the welder needs to be properly trained and highly skilled to be able to produce quality welds time after time. With automatic welding, you have a higher initial cost, more equipment to move around and more people to assist in the welding. You also still need an operator who knows how to weld so that if an adjustment needs to be made they can recognize and react to the issue.”
Edwards sees a trend of more wire and mechanized welding being used in the past five years.
“When comparing handheld vs. automated welding what comes to mind for most people is the SMAW process vs. automated GMAW process,” Spielbauer says. “SMAW can be quick to deploy and can require less support equipment. That being said, though, the process is highly dependent on the welder and is not as productive as mechanized welding. Mechanized welding provides a consistency in weld quality and production that can be hard or impossible to match with handheld processes particularly on long distance, large diameter pipelines.”
Spielbauer adds that automated systems provide the ability to accurately control the heat input levels needed for engineering critical assessment (ECA) tests and to successfully weld today’s high strength steel pipe, such as X-80 and X-100.
Pipeline integrity has been a major focus in the industry over the past decade, and ensuring quality welds is a primary part of the equation.
“Weld integrity starts with good filler metal and base metal,” Edwards says. “These are always being inspected to make sure they meet the required specifications. While the joint is being welded, a welding inspector will check to make sure the welders are staying within the parameters called out in the welding procedure. They X-ray the welds to make sure there are no defects. If there are, they are either repaired or the section of pipe is completely cut out and replaced.”
The welders themselves also play a vital role in maintaining integrity.
“As crews are pushed to maximum production, welders and operators start to become fatigued and become more prone to mistakes,” Spielbauer says. “With manual and semi-automatic processes, you are dependent to a greater extant on the welder. By implementing mechanized welding system, many of the operations involved in completing the weld are controlled by system, allowing for repeatable quality from start of the work day until the finish. Mechanized welding also incorporates a welding shack which provides protection from the elements, helping to ensure a quality weld.”
Furthermore, Spielbauer says that properly training personnel is “the best safeguard” in maintaining weld integrity.
Some developments in welding equipment that are aiding in pipeline integrity include the increased use
of low hydrogen consumables, which help reduce hydrogen cracking, Spielbauer adds.
“Also owning companies are increasingly providing their own requirements for welding above and beyond those outlined in codes such as API 1104,” Spielbauer says. “I think we will continue to see greater emphasis placed on weld quality and monitoring of the welds to ensure this quality is being repeated.”
Growing Field of Repair
With the number of aging pipelines in the ground, field repair welding is a growing market, Edwards says. While there may be some small differences depending on the size of the repair, the welding procedures are largely the same as for a new installation. In most cases, a section of pipe is cut out and replaced using a qualified welding procedure.
“I believe the average lifespan of a line is 35 years,” he says. “There are a great deal of lines that are running all over the country that were put in during or after World War II that need to be repaired.”
Causes for pipeline repair run the gamut.
“The weld could be finished, but the inspection found a defect in the X-ray,” Edwards says. “The weld could have had too much or not enough reinforcement on the inside of the pipe, and it caused an undercurrent effect eventually wearing the pipe out in that spot and causing leaks. It also could be something called hydrogen cracking or cold cracking. This occurs when the hydrogen in the weld was trapped and causes a crack in the weld causing blow outs, leaks or explosions.”
Spielbauer adds that start-stop regions of the weld are most prone to defects and care must be taken to properly prepare these areas prior to welding.
“While every effort is made to avoid causing a repair, inevitably they do occur,” he says. “This is why we require a field repair to fix the localized indication rather than cut out and start the whole joint over again.”
Across all of the construction industry, workforce shortages remain a major concern. It’s no surprise that these concerns are also found in the pipeline welding sector.
“The biggest challenge is the lack of skilled welders,” Edwards says. “Our skilled trades are lacking from the push of the last few generations to get a four-year degree.”
Spielbauer agrees, noting that an aging workforce means the industry could lose skilled welders before the younger generation can fill the void.
“In the United States, a figure which is commonly referenced is the average age of a welder is 55 years old,” he says. “A large percentage of the truly skilled welders in the marketplace are approaching retirement age and with them goes job knowledge and skill.”
To help the industry bridge that generation gap, welding equipment manufacturers have developed new welding processes to make it easier to learn and still make quality welds time after time, says Edwards, adding that automatic welding makes the task easier on both the younger and older welders.
“The younger guys have grown up in the computer and video game age and using remotes and joysticks are almost second nature, so they pick up on the controls fast,” he says. “The older welders look at it as a way to extend their careers because there is less wear and tear on their bodies.”
Training plays a key role in developing a new crop of skilled welders to fill the looming generation gap, Spielbauer adds. Welding manufacturers can partner with universities and trade schools to provide hands-on experience with equipment before entering the market, while owning companies can team with the manufacturers to provide training at local facilities to help prepare prospective welders prior to the start of a large project. Furthermore, on the job training and apprenticeship programs provide an opportunity to pair young welders with more experienced welders.
“A retiring welder may have 35 to 40 years of on the job experience,” Spielbauer says. “If someone new to the industry can learn a fraction of that, they will be miles ahead.”March 2015 Issue