Ultrasonic Testing on EUROFER Welded Joints for Determination of the Minimum Detectable Flaw Size.

The ferritic-martensitic steel EUROFER is intended for use as a structural material for blanket components of future fusion reactors. A blanket module consists of a multiplicity of diffusion-welded cooling plates, which are connected by TIG, EB or laser welding seams. For the quality assurance of these welding seams the ultrasonic non-destructive testing is currently examined. In the context of this work the manual testing and the ultrasonic immersion testing are considered for the examination of EUROFER parts including welding seams of different types (diffusion welding, electron-beam welding and TIG - welding). Differently arranged artificial flaws of varying sizes were introduced into the welding seams to determine their minimum detectable size. In essence, the artificially introduced flaws for immersion testing consisted of longitudinal holes and cross holes 0.2 mm to 1.0 mm in diameter as well as of tungsten wires whose diameter was in the range of 0.2 mm to 1

.0 mm. For manual testing holes were introduced with a diameter of 0.5mm only. Investigations were conducted using the KC 200 immersion testing facility developed by GE Inspection Technologies and the USD 15s by Krautkramer for manual scanning. Ultrasonic testing was performed intermitting straight- and angle beam examinations of longitudinal and transverse waves from sensors of different resolutions. The DAC (Distance Amplitude Correction) curves for flaws that are 0.2 mm and 0.1 mm in diameter were derived from the measuring results in addition.

Umfang: VI, 37 S.