Radiographic examination with isotopes is also called gammagraphy. It makes a diversity of mistakes in the welding, such as pores, cracks, weld slag, adhesion faults, poor restarts, and many more visible and detectable. The day activity of the isotope, the thickness of the material, the film quality or matching image plate, as well as the distance (film/image plate to source of radiation) all play a role in finding the right exposure time.
With this method, drawing up so-called shadow graphs “on stream” is easily done. This makes possible corrosion, erosion, as well as reductions in wall thickness of piping visible. Piping that is hard to access or insulated can also be irradiated, and wall thickness can thus also be determined.
Often, the double imaging technique is used with welding seams that have considerable differences in wall thickness, for example with connection elements. Usually, even more can be seen with CR (digital gammagraphy)!
Generally, this inspection method is very reliable. The advantage: it is manageable, easy to transport, and deployable in many areas. We use it for a plant’s facilities, in pipe trenches, and in all places where it is not possible to work with X-ray tubes.
For the digital gammagraphy, so-called imaging plates are used. They fulfil the same function as a film, however, the data is read out and subsequently appears digitally on a screen.
The plates allow a very quick and rapid capturing and evaluation of the images. As usual, you receive an inspection report. The inspection is carried out according to DIN EN ISO 17636-2 (digital). Naturally, the master data is tamper-proof and cannot be changed via photoshop, etc. Compressed files can easily be sent via email.
The advantage of this is obvious. Images can be viewed at any time or place with the applicable software (which we provide you with), they can be forwarded, integrated into the project, and be stored perfectly and with minimal use of storage capacity. Furthermore, it is possible to find any data (images) very quickly.
Image quality indicators, as well as the wire type IQI are present on each image and documented accordingly.
As with the X-ray examination of pipes, it is very important to use the right film. We have various quality films from brands such as Fuji and AGFA, all vacuum-packed. We also offer you these with lead foil of varying thickness (0.027 and 0.1mm). The image quality indicators, which are placed either further away or closer to the film, show the image quality of the film. These are available for various metals and with wire types of varying thickness. The testing instruction and, of course, the applicable norm indicate which wire type should be showing.
Our mobile lab vehicles are fully equipped. All our vehicles are equipped with fully automatic film processors or a CR scanner. This means that you are always provided with optimum quality. With film processing, results are already available after 8 minutes. With CR this already happens after ca. 30 seconds!
On demand, we offer on-site evaluations at the construction site. For the evaluation of the film we employ LED film viewers. Densitometer. For CR we have special laptops with high-resolution displays.
Protocolling is done with a laptop and printer, and the results are provided directly afterwards. If desired, we will send you the protocols and data directly from the construction site as a data file.
For the radiographic examination with gamma rays we use Selenium 75 or IR 192. For the gammagraphy it is important to use the correct source of radiation. Selenium 75 for thin-walled material, IR 192 for slightly thicker-walled material.
Our Isotopes – the radiation source – Selenium 75 and IR 192 are safely kept in transportable handy containers. We have all the necessary equipment for this – remote controls, various long guide tubes, collimators, source terminals, positioning devices, mountings, etc. These are used to keep radiation exposure at a minimum. A fast working pace, short exposure times, and the best possible quality are additional advantages.