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In order to maintain the efficient and reliable operation of pipelines and other equipment engineers need to know what techniques are available to extend the life of new components or refurbish worn or corroded ones and, just as important, what are their cost benefits compared to the use of expensive base materials or replacing the part? here are a number of options available to protect flanges and the internal surfaces of equipment but the final choice will normally be based on an evaluation of factors such as the application, required service life, operational priorities, installation deadlines and, of course, budget restraints. So, how can engineers ensure the long-term integrity of internal surfaces of pipelines, flanges and other equipment against aggressive corrosion caused by hazardous and corrosive LNG environments? Where budget is not a constraint, engineers can simply specify components in corrosion or wear resistant alloys known to withstand the conditions. However, this is rarely the case and other, more cost-effective options are usually sought. Where pipe, flanges or fittings and other components such as valves and pumps, require protection, weld overlay cladding is certainly a versatile option, providing the assurance of a heavy-duty metallurgic-ally-bonded protective layer that will not be degraded in hostile environments. Welding processes after first identifying the surfaces that need to be protected, engineers can choose from a number of welding processes and a wide range of cladding alloys. Weld overlay cladding technology presents the materials engineer with a wide choice of welding processes that offer immense flexibility. An almost infinite range of component shapes and sizes can be protected, with an equally wide range of base material/cladding alloy alternatives. The GTAW (TIG) process can be used in bores as small as 20mm, and is ideally suited for components of varied geometry, where the position of the welding head requires frequent adjustment. These could range from a simple flange that needs to be clad through the bore and across the sealing face, to a complex valve body with several interconnecting bores. This flexibility also lends itself to the cladding of irregular shaped components, such as pump and valve internals. GMAW (MIG), submerged arc and electroslag welding processes are used where large areas and thicker deposits are required. Fast deposition rates mean these methods also offer cost savings. A wider selection of consumable materials, which may not be produced in the standard solid wire form, is also available. Selection of the most appropriate welding process is largely dependent on factors such as the size of the clad area; access to the area to be clad; alloy type, specified clad thickness; chemical composition limits; welding position; and NDT acceptance standards. STORY HIGHLIGHTS There is a nationwide shortage of welders Graduates of training programs can make $20 an hour Demand is expected to grow 15% by 2020 Welders are retiring just as demand for their skills is picking up. High school students are showing interest in training programs. The acrid smell of liquified metal hangs heavy in the air as superheated sparks shower behind the blue plastic curtains that shield passersby. Inside the welding booth, one hand inside a dirty yellow glove takes hold of two strips of steel while the other wraps around the base of a gun that will employ what seems more like magic than science to bond the strips together. The joint complete, a gloved hand lifts a dark mask, revealing a face on which is written the desire to create with patience and precision. The act of welding to some is more than a craft. It's an art that hundreds of thousands will need to master if their ranks are to keep pace with growing demand. In 2008, there was a nationwide shortage of about 250,000 welders, and that figure has remained relatively constant to this day, says Jason Walsh, who heads the welding technology program at Front Range Community College in Colorado. There were 337,300 jobs for welders, cutters, solderers and brass workers in 2010, according to the U.S. Department of Labor. By 2020 that number is expected to have grown 15%. As a result, enrollment in welding courses at Front Range has increased — from about 60 each semester nine years ago, when Walsh started teaching there, to 350 this year. "From (the welder's) standpoint, the recession's basically over, and there's a huge upturn in work," says Bryan McClure, a training manager with LPR Construction in Loveland, Colo. Specializing in heavy steel construction, LPR's projects have included the backbones for two baseball parks, the Colorado Rockies' Coors Field in Denver and Marlins Park in Miami. And it's hiring FRCC students, "absolutely," McClure said, paying them $16 an hour. Keeping up with demand "Right now, they are disappearing," Walsh said of welders across the U.S., the majority of whom are 50-plus years old and either retired or close to retirement. "We're not replacing them as quickly as they're going away." And that shrinking workforce is needed to address America's aging infrastructure and needs of the energy industry, Walsh said. "We have pipelines that stretch from Utah to Pennsylvania, from Canada to Texas," Walsh said, "and that requires a lot of welders." One of those welders is a former student who, at 19, is training in underwater welding in Florida. He's making $80,000 a year doing so. High School senior Dillan Morrison grew up in a family of welders and thinks he'll continue the legacy by taking up a job in either pipeline or fabrication welding. "I know there's a high demand," he said, his fingers and palms blackened an hour into class. Underwater welders help set up equipment and structures that are below the surface. They must be both skilled welders and skilled divers with commercial diving certification. They work on projects such as ship repair, oil platform maintenance, and oil or gas pipeline installation. Underwater welders generally work on a project-by-project basis, and those with experience and good reputations can earn up to $100,000 a year, according to the American Welding Society. They also may be responsible for planning projects, acquiring materials and equipment, hiring personnel, taking videos and photographs of projects, and inspecting the work. Many underwater welders go on to become managers, engineers, supervisors, underwater trainers and inspectors.
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Welding Technology ProgramThe Welding Technology program at Madison High school in Houston TX, prepares students for a variety of occupations in welding. Welding by gas and electricity (either arc or resistance) is a major part of this program. Methods used to fabricate and weld parts made of aluminum, steel, stainless steel and most other alloys are included in this program. Students prepare to take certification exams in welding and safety. This program offers an opportunity for certification from the American Welding Society Archives
March 2023
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