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In the evolving application of repair technologies for turbomachinery, complex geometries, demanding service conditions and the need for reduced repair times are constant challenges.
The industry demands repair technologies that not only adapt to intricate designs but also minimize downtime. Enter laser welding, a technology that has proven its ability to meet these stringent requirements over the past decade.
Laser welding, a process that uses a laser beam as the heat source to fuse metallic filler material onto a surface, offers numerous advantages. One of the most significant benefits is the limited need for post-weld heat treatment (PWHT). This minimizes the risk of distortion in the repaired components, which is a common issue with traditional welding methods. Additionally, laser welding systems feature integrated controls that provide precise positional accuracy, akin to Computerized Numerically Controlled machining centers, thereby enhancing the quality of the repairs.
Application #1: Screw compressor seal strips
Screw compressor rotor seal strips illustrate the precision and efficiency of laser welding. Traditionally, these seal strips were repaired using gas tungsten arc welding (GTAW) combined with multi-axis machining. The process involved removing the damaged seal strips, depositing filler metal with GTAW, and then machining the strips to their final profile. This method, while effective, posed several challenges, including potential lobe distortion and lengthy repair times.
GTAW introduces substantial heat, risking distortion of the lobes and altering rotor clearances during operation, potentially affecting compressor performance. Additionally, multi-axis machining centers often face high demand, resulting in long wait times for repairs.
Laser welding addresses these issues by minimizing heat input, thereby preventing lobe distortion. The fine bead size of laser welds can be adjusted for each seal strip width, reducing the need for extensive machining. Integrated control systems position the weld precisely, making it possible to achieve the desired seal strip dimensions without the need for multi-axis machining centers. Consequently, repairs are not only faster but also more precise, significantly reducing overall repair timelines.
Application #2: Compressor casing
Equipment located in harsh environments, such as oil platforms in the Gulf of Mexico, faces extreme weather and salt-rich air, which can severely affect seal areas. Large components like outer casings of vertically split compressors require meticulous repair processes. Traditional GTAW repairs necessitate preheating, significant heat input, and often PWHT, which risks distorting other critical features.
Laser welding, with its superior heat control, eliminates the need for preheating and PWHT, thereby avoiding distortion. The process complies with stringent quality standards, as outlined in ASME Section IX, and allows for the application of corrosion-resistant overlays such as Inconel 625. These overlays enhance the longevity of repairs and the overall durability of the machinery in harsh environments.
The petrochemical industry continuously faces the challenge of repairing complex components under demanding conditions while striving to minimize downtime. Laser welding emerges as a transformative technology, offering precise, efficient, and reliable repairs. By addressing the limitations of traditional welding methods, laser welding ensures that even the most intricate parts can be restored to optimal condition quickly and without compromising quality.
At the forefront of this technological advancement is Houston-based MAN Energy Solutions. Its state-of-the-art 100,000 square foot repair center houses the largest laser welding cell dedicated to turbomachinery in North America. Supported by a team of highly skilled engineers and technicians, MAN Energy Solutions is equipped to meet industry’s turbomachinery repair needs, ensuring operations continue to run smoothly and efficiently.
For more information, visit MAN Energy.
