FSWBot: Friction stir welding crawler for internal repair and refurbishment of pipelines
FSWBot aimed to create a robotic system, integrating several technologies including friction stir welding (FSW), ultrasonic non-destructive testing (NDT), and milling and patch deployment, that could be deployed to conduct repairs on subsea pipelines while they are operational. It was designed to be controlled remotely by engineers at a safe distance from the pipeline.
The FSWBot solution comprises four articulated carriages: a power generation carriage, two carriages for battery storage and one for the control system. The robot works by:
- Entering a pipe segment that contains defects previously mapped out using a magnetic flux leakage (MFL) survey
- Correctly positioning itself to perform the repair on the first defect
- Machining away from the corroded area and producing a pocket in the pipe wall into which a steel patch will be placed
- Welding the patch into place
- Using the milling tool to ensure the weld is flush with the pipe wall
The machine then uses NDT to inspect the weld, after which it unclamps and moves downstream to repeat the process on any further defects. The data generated, such as location, and pre- and post-weld ultrasonic scan data, is stored for later use, in order to increase the level of autonomy using artificial intelligence (AI) and machine learning. The robot is controlled remotely by engineers at a safe distance from the pipeline.
Once the prototype FSW system was ready for testing, the project partners demonstrated that a patch weld can be carried out in-situ, for example, to rectify a corrosion induced defect on a 36 inch (91cm) diameter, oil-filled, steel export pipe.
Partners: Forth Engineering, Innvotek, London South Bank University, TWI and the Joining 4.0 Innovation centre (J4IC).
FSWBot was funded by Innovate UK.