Welding on the Right-of-Way: Pipeline Welding True Test of Equipment, Skill
March 5, 2011
Local 798 and Sheehan Pipe Line Construction Company descend on "pipeliners capital of the world" to build brand new X70 natural gas pipeline. Also: Miller works with Local 798 to design next generation pipeline welder.
A brand new, 185-mile X70 natural gas pipeline was constructed in the summer and fall of 2010 that cuts through the heart of White County, Arkansas. There lies Bald Knob, a town widely considered to be the “pipeliners capital of the world”. UA Local 798 business agent Phillip Wallace reports that the area surrounding Bald Knob has more pipeline welders, operators, superintendents and inspectors per capita than any other region in the country. As transmission pipelines from every corner of the country converged upon the area decades ago, young men signed on and made a career of pipeline welding.
That career choice made nomads of these skilled tradesmen. When Sheehan Pipe Line Construction Company began work on its 65-mile stretch of the new pipeline, it was an opportunity to call many of the “Bald Knobbers” home. The area sits on the Fayetteville Shale, and the new pipeline represented the first opportunity in years that many of these pipeline welders had to work near their home.
Sheehan’s portion of the pipeline—a 65-mile stretch of 42-in. X70 pipe—stretches through rocky terrain exposed to wind, dust and heat. It adequately represents the rigorous environments pipeline welders, and their engine-driven welder generators, face daily.
“The machine is carried over rough terrain,” says Farron Hollabaugh, director of training, Local 798. “It’s exposed to the elements, whether it’s cold, extreme heat, rain, or snow. It has to be a strong machine to withstand that and to still work day-in and day-out. It’s the welder’s lifeline. They have to have reliable equipment.”
Looking for Consistency in a Welder
While much of today’s pipeline welding is mechanized, manual processes are often specified for tie-ins and other critical joints. The 42-in. pipe that makes up the pipeline features a nominal wall thickness of .435 in. on the main line, and is as thick as .888 in. where it travels under roads and residential areas. The pipe’s joint is preheated to 250 degrees and is monitored/maintained throughout the welding process to meet the pipeline’s standard. Each joint then undergoes x-ray testing to ensure quality.
The root pass is made with an E6010 cellulosic electrode for deep penetration and increased ductility, with welding output ranging from 135 to 155 amps. The organic compounds in the electrode’s coating (including cellulose) break down during the welding process to form gasses that strengthen the arc and provide good penetration in all positions around the joint. All passes after the root are performed with an E8010 cellulosic electrode with welding output ranging from 150 to 185 amps.
Temperatures during the welding process regularly exceed 100 degrees in the summer, and welders are always fighting dirt, dust and humidity when working in wide-open environments. Factor in the quality of the joint prep, out-of-roundness, high-low fit-up and any number of other pipe-related variables, and the quality of the equipment is the last thing anyone in the field wants to worry about. Carmen Moody, pipeline welder, Local 798, has relied on Miller’s PipePro™ 304 for the last seven years:
“It’s consistent,” he says. “It’s the same every day from seven o’clock in the morning until five o’clock in the evening. Whether it’s 40 degrees or 104 degrees, the puddle control, the amperage and the voltage is all the same.”
Miller Works with Local 798 to Build New and Improved Pipeline Welder
While machines like the PipePro 304 have served the pipeline welding industry admirably, Miller teamed up with Local 798—the largest pipeline local in the United States—to design a new machine that would stand up to the harsh, demanding work environment while also evolving to meet the changing needs of the industry. The result: Miller’s Big Blue® 350 PipePro diesel engine-driven welder/AC generator
“We’ve worked extensively with Miller on the development of this,” says Hollabaugh. “It’s a strong machine that has good arc characteristics. You get the exact same amperage out of it every time you use it as opposed to a DC generator that varies with temperature. They can count on it being the same weld characteristics every time they strike an arc.”
The Big Blue 350 PipePro provides pipeline welders 20 to 400 amps for both DC Stick (325 amps at 100 percent duty cycle) and DC TIG welding, 14 to 40 volts for MIG and Flux Cored welding (350 amps at 100 percent duty cycle), and 12,000 watt peak/10,000 watts continuous auxiliary generator power for running tools. One of the biggest advantages is the new Mitsubishi 24.4 HP diesel engine that lowers RPM to 1,850. This reduces fuel consumption by as much as 50 percent—a critical factor to pipeline welders who are independent contractors who own their own rigs and shoulder the weight of their operating costs.
“Fuel symbolizes money right out of each of these guy’s pockets,” says Joe Gitter, product manager, Miller Electric Mfg. Co. “This machine will use 20-percent less fuel than the machine it replaces, and potentially 40- to 50-percent compared to DC generators available on the market.”
The Big Blue 350 PipePro features Infinite Arc Control that allows arc characteristics to be tailored to specific applications in Stick, MIG and Flux Cored welding. Overall arc quality is improved, and MIG/Flux Cored controls have been enhanced and simplified to optimize the machine for wire welding. It also features Miller’s “Vault”, a sealed aluminum case that protects the machine’s circuit board from dirt, moisture and heat to ensure consistent operation, including unwavering arc consistency and generator power.
“Reliability is paramount to these guys,” says Gitter. “They’re getting paid to weld, not to sit around and wait at the repair shop.”
The machine is available in an optional stainless steel package to withstand corrosive elements, and all models come standard with a LINE-X®-coated top cover for added durability and reliability. It’s smaller than previous models (56-in. depth) to optimize truck space. The machine meets all Tier 4i requirements and is designed to operate for 10,000 hours before the first basic overhaul.
While the machine was officially introduced in September, Local 798 members received a sneak peak of the product at a Pipeliner’s Appreciation Event sponsored by Miller, WelsCo and Hypertherm.