Inspection of thin steel gauge welds for the shipping industry using laser guided inspection robot

In the shipping industry sector, structural failure is a major cause of the loss of ships, vessels and tankers resulting in loss of life and pollution of the world’s oceans, seas and coastal waters of Europe. Indeed, it has been reported in 2006, that each year over 400 ocean going ships sink, many as a result of weakened structures due to corrosion and inadequate/poor welding quality. Most of the inspection techniques used today proved to be disruptive to the manufacturing process and far from being cost effective. Additionally, as the current generation of ships are being built from thinner section steels (10mm or less) to lower the cost of build and ship operation, typical assessment methods are not as effective as for thicker sections. Therefore, there is a real need for more reliable, faster, cost effective and safer inspection techniques. A novel inspection system using a crawling robot was developed in order to deploy remote volumetric, surface and visual inspection to verify the integrity of welds during manufacture and in service shipping vessels. By the combination of ultrasonic phased array, electromagnetic ACFM and laser optical methods, this system aimed for the detection and the sizing of surface breaking and sub-surface flaws. A tracking system and a self-control robot were developed to allow the automatic inspection following the weld run. This work was carried out in the FP7 European funded project XScan with the collaboration of seven European companies including Lloyd’s Register EMEA, Vermon, Tecnitest, Spectrumlabs, TWI, Brunel University and Innora. Several laboratory trials with manual scanning of reference samples and scanning with the overall X-Scan system allowed the comparison of manual inspection and semi-automated inspection. The X-Scan system was then put to the test on site as to evaluate its performance in a less controlled environment as to observe whether the different sub-systems can function in such conditions and generate adequate results. This paper aims to present the background of the X-Scan inspection system, to present the results of the X-Scan project; to demonstrate the performance of this automatic inspection system.