New testing device of WBK - Seilprüfstelle for non-destructive wire rope testing with three measuring circuits

The first non-destructive wire rope testing device was developed at WBK-Seilprüfstelle as early as in 1931. Since those days non-destructive testing has proved to be an indispensable tool to support visual inspection in assessing the damage condition of steel wire ropes. According to the obtained findings it becomes possible to predict the likely progress of the existing type of damage. The underlying principle of the historical and the more recent testing devices of WBK-Seilprüfstelle is the so called "magnetic stray flux method" ¹⁾. It is particularly suited to identify outer and inner wire breaks from the recorded signals ²⁾. Furthermore it is possible to detect the existence of corrosion by applying the stray flux method, because corrosion pits give rise to stray fluxes too. They produce a more random like type of signal. But whenever the metallic area of a rope is reduced by corrosion or wear, the diagram will not give an indication of the amount of metallic area loss. In the case of corrosion it is exclusively the shape and depth of corrosion pits which produce the measuring signal.