Applus+ leads the way with ultrasonic imaging (IWEX) for girth weld inspection

08/10/2020

    Ever since the introduction and development of welding technologies for pipeline construction, non-destructive testing (NDT) of girth welds has become a vital part of the quality and integrity assurance of the pipeline. With the improvement of welding technologies and the increase in challenging applications, the demand for more accurate and reliable NDT methods has also grown. Applus+ RTD has always been a pioneer in the development of new NDT methods and strategies. 

    One of the latest innovations in ultrasonic NDT solutions for girth weld inspection is the Applus+ RTD IWEX technology. This technology allows for real time 2D and 3D imaging of possible indications in girth welds whereby the position, height and orientation of the indication are accurately displayed within the weld geometry. As opposed to radiography, this approach does not require any time for film development or hazardous radiation. Compared to traditional ultrasonic technologies like manual UT, zonal discrimination automate UT (AUT) or phased array sectorial scan, the IWEX technology provides comprehensive results in the form of 2D and interactive 3D images that are easy to interpret, even by non-NDT experts. Furthermore, the process to set up the equipment does not necessarily require a calibration block with known reference targets.

    The benefits of the IWEX technology are nicely illustrated with the successful conclusion of a recent project in Germany. The welding contractor (PPT) proposed to use automated welding for the manufacturing of a pipeline near the town of Hamm for one of Germany’s leading owners of pipeline systems OGE (Open Grid Europe). As per this company’s requirement, all automated welds had to be inspected with an automated UT system qualified by an independent party (TüV). The IWEX technology has been qualified by several independent parties, such as DNV (according to OS-F101), Dekra (according to the GasUnie standard CSW-50-E) and TüV. Typically, the manufacturing of dedicated calibration blocks for traditional AUT and the preparation of a system set-up is time-consuming. For this particular project, there was insufficient preparation time. To the satisfaction of the client and contractor, Applus+ managed to set-up and mobilise the IWEX equipment at a very short notice, without the need for a calibration block.  

    Due to the relatively small wall thickness (6,3mm), the acceptance criteria were stringent and challenging for traditional UT technologies. However, with the right choice of ultrasonic array probes and wedges, Applus+ specialists could obtain highly focused images whereby indications less than 1mm in height and 5mm in length could clearly and reliably be identified with impressive accuracy and a pixel resolution of 0,1 x 0,1 mm. 

    During the start of the project, small indications were found in the first couple of welds. The indications appeared to be at the same circumferential location and depth. Thanks to the comprehensive 2D and 3D images obtained, the welding crew was able to understand the nature of these indications, such that it was possible to address and improve the corresponding parameters of the welding equipment. With fast feedback and good communication between the welding crew and the IWEX inspection crew, the weld quality could be improved immediately. Thereby, it was possible to maintain production efficiency and avoid unnecessary costs for weld repair, demonstrating once again Applus+ standing as a trusted partner of the industrial sector and leading agent of innovation