How Does NDT Keep Ships Afloat?
By Rachel Lieberman
Those of you who have ever taken a cruise have probably wondered how such a huge vessel manages to stay safely afloat when crossing large bodies of water. Few are aware of the major role that NDT weld inspection plays in ensuring the vessels’ safety.
The ship building structure process includes two main stages: Production and NDT inspection of the ship’s countless welds. Both of these processes are very time consuming. With the aim of facilitating the production process, some shipyards have transferred to Laser Beam Welding. In some cases, this system enables the welding of plates of up to 30 meters at one time.
Thus, the welding time has been effectively shortened. But what can be done to facilitate the NDT inspection process? Conventional NDT weld inspection methods have several serious drawbacks: Due to the high radiation when conventional methods are used, NDT testing is conducted during night shifts, doubling labor costs. With film X-ray, reshoots are often required and development time is lengthy, making the assessment process slow and complicated. When using conventional X-ray methods, cables must be stretched over extremely large areas and reach almost inaccessible locations. Cables are often cut unintentionally, due to the steel plates’ sharp edges.
In order to overcome all of the obstacles described above, leading shipyards searched for an all-in-one NDT solution. They discovered the Vidisco portable Digital Radiography (DR) systems, which significantly expedite the NDT inspection process in shipyards and resolve all of the prevalent NDT problems. Bottom line, these systems save the shipyard significant amounts of time and money.
Vidisco’s portable DR systems effectively eliminate bottlenecks in the NDT inspection process and save precious time in shipyard production. The DDA imagers used in DR are highly sensitive, thus enabling the use of X-ray sources that emit very low doses (e.g., pulsed X-ray sources). Safety zones are reduced. As there is a minimal risk, NDT weld inspections can take place during day shifts alongside the regular production work, saving both time and money. In addition, Vidisco’s portable DR systems provide top-quality images on a laptop screen within seconds and upon request, thus eliminating unnecessary waits, reducing the analysis time and enabling immediate action. These X-ray systems are truly portable and lightweight, which means that they can easily be carried to and installed in hard-to-reach, elevated spots even in the roughest conditions. Due to the fact that they are powered by batteries and equipped with wireless modules, these portable DR systems operate without tangled wires and cables.
The shipyard industry is required to meet various international standards in the area of NDT inspection. Such certification is provided to X-ray manufacturers that support these standards, including Vidisco Ltd.
Vidisco’s portable DR systems effectively resolve many of the difficulties encountered in shipyard NDT using conventional radiography. But these systems have even more to offer: They are equipped with the company’s proprietary XBitPro software, which contains various enhancement tools such as Stitching and Advanced Measurement capabilities. The software’s stitching feature enables the system to take top-quality images that it produced and stitch them together automatically based on the pixel level throughout the image. The software also provides excellent measurement capabilities, enhancing minute defects. Large weld sections can be viewed at once on screen with great detail.
All of these features combine in Vidisco’s range of portable digital X-ray systems to present an ideal NDT solution based on leading DR technology for both small and large shipyards.
This article was first presented by Vidisco NDT expert Ron Pincu at the BINDT/MT Exhibition 2011.