The inspection of steel welds is a requirement in many safety critical applications, with X-rays offering an excellent visual aid in quality monitoring of such parts. In order to penetrate the steel and the weld, high energy X-rays are usually required though, depending on the material's thickness and the length of material the X-ray beams must traverse. The high beam energies can seriously degrade the X-ray detectors' life expectancy and image quality, so in order to ensure consistent image quality traditional X-ray film has been used, in spite of its drawbacks regarding the ecological impact of the chemical process and the significant efforts involved if archives of the welds must be maintained.
This paper presents an alternative solution to the traditional photochemical archival approach using a custom X-ray detector developed specifically for the inspection of welded seams. The detector is protected from the damaging effects of high energy X-rays used in steel weld inspection, thus maintaining constant image quality over time. Electronic images offer the possibility of automatic image processing of the welded seams, and the detector's constant image quality has also allowed it to eliminate the photochemical process entirely and progress to an electronic archival system.
The paper will present the operating principle and background of the application as well as the experiences gained from its use over the past years at an automatic welding station. This paper also presents data and images generated with the system in conjunction with automatic weld inspection software developed for steel welded seams.