WELDING | NDE & INSPECTION, DIAGNOSTICS & ROBOTICS
meeting for forty-seven participants over Microsoft Teams was a first for us all. Oddities became the norm — like test rigs having their own web addresses so that they could be invited to meetings. As infection rates ebbed and flowed, and government
restrictions changed, it became inevitable that the original delivery plan had to change. It was not possible to demonstrate the technology on a single platform, owing to travel and social distancing restrictions. A ‘plan B’ was needed urgently and the team came up with a solution. Two autonomous and robotically-enabled demonstrators were built, one at each research centre, joined virtually by a software emulator. A shared common workpiece physically travelled by courier between the centres to demonstrate that both the weld process monitoring and NDT inspection system elements could detect the same defects. The change was significant, extending the project to
December 2021. Costs increased as well, but were controlled by the research centres’ abilities to acquire additional equipment and resources, and the goodwill of the industrial partners who continued with the engagement.
AWESIM outcomes To measure whether a system can detect a weld defect in real-time, it is essential to have the means to create a quantifiable and repeatable defect when it is needed. This might sound easy but it is not. Modern autonomous or robotic welding centres are designed to minimise the occurrence of weld defects. Trying to get such systems to create a defect of a measurable, predictable size when needed took considerable ingenuity. Once this challenge had been met it was possible to
test the technology to find engineered defects of different forms, such as root weld failure, lack of side wall fusion, inclusions and porosity. Nuclear AMRC delivered a weld process condition
monitoring system that brought together the processed output from four dissimilar sensors to reach real-time decisions as to whether a fusion weld defect was present or not. The sensors included a laser weld profile sensor, a high definition camera, an acoustic sensor and a weld process power monitoring sensor. While the sensors were commercially-off-the-shelf
components, the data analysis software was not. Bespoke data analytics and image processing methods involving neural networks and machine learning algorithms were developed. Aggregation of the processed data sets was used to confirm in real time whether a defect was present. ANRC continued with its development of a phased
array ultrasound sensor capable of operating at surface temperatures up to 350°C. A combination of hardware and software development took place. A roller probe configuration using a tyre made from a custom temperature resistant polymer, cooled internally, was chosen and developed. This meant no acoustic couplant was needed and the forced cooling ensured the sensor could operate without restriction — 24 hours per day, seven days per week if needed. Compensation for the variation in the speed of sound in steel at temperature was factored into the full matrix capture (FMC) phased array ultrasound testing (PAUT) measurement approach for the freshly deposited weld bead. It was shown that the prototype sensor and software suite can detect, locate and size defects with the same accuracy as similar measurements carried out at ambient
temperatures. By avoiding the need for a liquid acoustic couplant being applied to the surface of the component being inspected, time and cost savings can be realised. The team showed that the real-time capability of the
technology gave operators a higher degree of confidence that the welding is ‘right first time’, improving schedule certainty while maintaining quality. Abortive welding was avoided, as the welding process could be stopped as soon as an out-of-specification weld was found. This process-control step leads to increased productivity and optimisation of the energy and materials used, improving sustainability. Additional benefits can be realised by reducing the dependence on radiographic weld inspection, further saving time and reducing hazards to operators by reducing radiation risks. The team were able to successfully demonstrate the AWESIM technology. They performed real-time detection of defects in September 2021 to representatives from BEIS, the Office for Nuclear Regulation and the Environment Agency face-to-face. Realisation of many of the benefits identified before the project began is in sight. Patent applications were prepared covering all elements of the technology and patents have been filed.
Next steps Planning is under way to develop the technology for commercial deployment. The consortium members are developing the technology to follow up on secondary opportunities identified, but not worked on, in AWESIM. The AWESIM project resulted in a technology that offers
a potentially disruptive step-change in the technology used for welding and NDT of high integrity components. The benefits to the nuclear industry are clear. The
technology is being applied to the future nuclear new- build programmes (Sizewell C, UK SMR, advanced modular reactors and fusion reactors). Although the technology was developed using government funds and focused on nuclear industry applications, it could apply to any industry that requires high-integrity welded fabrications. ■
Below: Temperature compensated phased array ultrasound sensor at ANRC, University of Strathclyde
HDR camera
F/T sensor PAUT roller probe
TIG torch
Pipe rotation
www.neimagazine.com | April 2022 | 29
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