| 摘要 |
<p>Cracks and surface flaws in billets are detected by heating the surface of the work-piece by means of high frequency current, the heating taking place while the work-piece is brought to pass in its longitudinal direction through a high frequency induction coil. That part of the work-piece, which has just left the coil is immediately, while the workpiece is still passing through the coil, scanned by means of infrared recording equipment which records the temperature distribution across the work-piece. the emission coeffisient for the different work-pieces is increased and differences equalized by moistening the surface of the work-piece with an appropriate liquid, for instance water to which have been added components for reduction of the surface tension.</p> |
