Infrared Thermal Imaging Technology in Non-Destructive Inspection of Ship Structures

Author: Bryan Ng – Marketing Manager

The infrared thermal imaging system plays a key role in the non-destructive structural investigation in the shipbuilding industry. The non-destructive testing technology relies on the infrared thermal imaging system to monitor the ship-building process, providing useful detection data and thermal images for the structural quality of the ship, to replace the traditional unreliability of human visual judgment.

Thermal imaging technology is increasingly popular in the shipbuilding industry due to its simplicity, effectiveness, and ease of operation. This article introduces the application of an infrared thermal imaging system in detecting defects in ship structure.

1. Applications of Infrared Thermal Imaging System in Ship Structure Inspection

Marine ships usually work in harsh environments whereby accurate testing procedures and modern non-destructive testing techniques are needed to help ensure their structural quality. Structural quality will ultimately affect the life of the ship, safety, reliability of use, maintenance frequency, and total cost. Infrared thermography, a non-destructive testing technology that is easy to implement, will help detect and quantify defects. This inspection tool can be used in many naval and marine applications to inspect the interior and exterior areas of a vessel.

2. Monitoring Ship Welding Quality

In the process of shipbuilding, it is very important to control the welding quality. Whether it is spot welding, friction stir welding, or metal inert gas arc welding, the most important is to combine two pieces of metal in a reliable way.  Good quality welding can be achieved by heating the metal parts in a uniform heating method until the melting point. The traditional testing methods for welding quality mainly include hammering and visual inspection. However, these methods are extremely subjective. The infrared thermal imaging system is used to monitor the temperature change in the welding process and detailed information about the welding strength which could be obtained through the generated thermal image.

3. Detect Paintings on the Ship’s Surface

Do you also know that infrared thermal imaging systems have also been used for paint surface detection in automobile manufacturing process measurement? An infrared thermal imaging system can directly visualize the temperature profile of large surfaces on a ship and it’s ideal for monitoring the painting process of ships. By combining thermal images with paint layer thicknesses, a thickness map for each tank can be created instantly and in real-time before the paint dries. This also makes it easier for operators to repair coated fuel tanks.

Compared with other technologies, the biggest advantage of infrared thermal imaging technology is that it can integrate the temperature monitoring process into the painting process. Using this method, it is possible to directly find out which areas need to be repainted and which areas have been painted. This method is more effective than ultrasonic because you have to spray the paint first and then inspect it afterward.

3. Uncoated Surfaces Detection

Another application of infrared thermal imaging systems in shipbuilding is the detection of uncoated surfaces in ballast water tanks. In this application, thermal imaging technology can detect uncoated spots of different sizes because different sizes of spots have different emissivity and thermal performance. The technique could be used in conjunction with other imaging methods, such as fluorescence imaging, which involves using ultraviolet light to study paint materials containing fluorescent pigments.

4. Detection of Ship Primer Corrosion

Using an infrared thermal imaging system, it is possible to check whether the bottom is corroded or deformed without removing the paint. Cruise ships sometimes have ballast tanks filled with oil when they returned from the Middle Eastern, but when going to those destinations, those same tanks are filled with salt water, all to keep the ships balanced during the one-way trip, The problem is that these brines are very corrosive, and this corrosive medium can destroy the coating on the surface of the boat. We can use infrared thermal imaging for maintenance inspection of ballast water tanks, and the staff can see where the corrosion points are without removing the surface coating.

5. Inspect Inaccessible Parts of the Ship

Infrared thermal imaging systems are ideal for shipyards to inspect dark or hard-to-reach places on ships. This technology can detect some hidden, hard-to-detect places without physical contact. The 2D scanning nature of the technology is beneficial due to the often very large size of marine vessels. With this technique, no sample preparation and surface preparation procedures are required, and it can be performed on many different formulations of paints and materials. Therefore, the technique is not limited by the properties of materials.

6. Conclusion

In addition to the above applications, infrared thermal imaging systems also allow researchers to control the resolution of detection by adjusting the spatial dimensions of the focal plane array and prisms. This also means that a large number of ship detection problems can be solved by using the technology. Now you know the importance of infrared thermal imaging systems and their applications in ship structure inspection, it’s critical to get reliable infrared lenses from a reliable supplier. Wavelength Opto-Electronic provides a variety of high-performance infrared optical lenses for life sciences, security, machine vision, thermal imaging, and industrial applications, from design and development to manufacturing and assembling IR systems, providing customers with a complete set of infrared optical solutions.