Both radiography and ultrasonic testing are valuable in non-destructive testing of welds and materials. Both methods also require a high skill level and training to ensure accurate readings and avoid dangers as well (especially in radiography where X-rays or gamma rays are utilised).
Which testing method is better? It actually depends on the specific application and as implied earlier, the accuracy of the readings heavily depend on the operator’s training and skill level. After all, the manner of testing and the interpretation of test results depend on the operators. The tools and technologies only aid the operators in performing the inspection work.
About industrial radiography and ultrasonic testing
To give you a better overview (and hence some of the inherent advantages) of radiography and ultrasonic testing, we’ll discuss the basic mechanism of both and how they can be applied in inspection of welds.
Let’s start with radiography. This method uses X-rays and gamma rays that penetrate a solid object (our welds and weld interiors) and then go onto a photographic film. As with human X-ray images, the result will be an image that shows the material’s internal structure. The resulting images will vary depending on the material’s thickness on different sections and areas which could be due to porosity, voids, inclusions, cracks and other discontinuities.
In contrast to radiography, ultrasonic testing uses mechanical vibrations and ultrasonic waves. When those ultrasonic waves hit a discontinuity, the reflected energy goes back to the transducer. The resulting readings show the intensity of the reflection and the distance. The readings vary because the amount of sound reflected back will be reduced if the waves encountered discontinuities and other imperfections.
Ultrasonic testing is generally suited for inspection of thicker sections accessible from only one side. This method has found applications in testing both ferrous and nonferrous materials. With ultrasonic testing, operators are able to locate the exact position of a weld’s discontinuity.
Each testing method has its own advantages and the choice of method may depend on the welds you have, the material type, accessibility, time required for inspection, costs, available operators and other factors. Extensive technical knowledge is also required for both methods to ensure accurate readings and safety in the field.
If you require more technical information about industrial radiography and ultrasonic testing, you can contact us here at NDT Equipment Sales. You can tell us your requirements and we can discuss an accurate and cost-effective testing method and equipment for your specific application.