TY - CONF A1 - Thomas, Hans-Martin A1 - Stadthaus, Meinhard A1 - Baugatz, J. A1 - König, W. A1 - Migoun, N. P. A1 - Prokhorenko, P. P. A1 - Gnusin, A. B. T1 - Reproducibility Problem for the Procedure of Type Testing of Liquid Penetrants N2 - Apparently that the type testing procedure should be conducted under the conditions ensuring reproducibility of its outcomes. We investigated various factors effecting upon the reproducibility. To obtain quantitative characteristics of indication’s visibility the image-processing hard-and software were used. It was established that there are two main groups of these factors. The first depends on the differences between various test panels, which are used for type testing. The second one concerns the reproducibility of some stages of penetrant testing procedure (excess penetrant removing and developer application). The recommendations to increase the reproducibility of type testing are developed and illustrated experimentally. The determination of penetrant system sensitivity as a part of type testing should be conducted ensuring reproducibility of the result. We investigated some factors effecting the reproducibility. To obtain quantitative characteristics of indication’s visibility, an image processing system was used [1]. We used 3 different sets of reference blocks (rb1, rb2, rb3) corresponding to type 1 of EN ISO 3452-3 [2]. Two fluorescent penetrants with different sensitivities and the same wet solvent developer were used. It was established that the reproducibility of type testing is influenced by mainly two principal factors. First there are the differences between reference blocks. Second one concerns the reproducibility of penetrant testing procedure, especially excess penetrant removal and developer application. According to EN ISO 3452-3 a reference block for determination of sensitivity level of fluorescent penetrants consists of a set of three nickel-chrome plated panels with 10, 20 and 30 µm plating thickness. Transverse cracks are made in each panel by stretching the panels in the longitudinal direction and width to depth ratio of the cracks should be approximately 1/20. Each panel presents a certain sensitivity level, which is characterised by the level of visibility of the indication. The highest level 3 corresponds to the panel with 10 µm thickness plating. Each panel is cut longitudinally (perpendicular to the crack) so that 2 sheets (panels A and B) with nearly the same cracks will be produced. These panels A and B of a reference block are used for relative evaluation, for example to compare sensitivities of two penetrants. It is considered that the application of the same penetrant to both panels with subsequent adequate development results in the same visibility of the indications on these panels. Quantitative correlations between the abilities of the reference blocks used for determining of the sensitivity were obtained in our investigations. We used the relations between the measured values of light-fluxes from the indications of similar comparing areas on two panels. These indications correspond to certain cracks’ parts of the same total length on both comparing areas. The relations of the steps between the panel are responsible for the definition of the sensitivity groups. From our investigations it follows that the steps of the different sets are different. Besides it was established that the indication‘s visibility for the same penetrant applied on different reference blocks might have a considerable difference depending on the penetrant sensitivity: the higher penetrant’ sensitivity, the smaller is such a difference between the steps 30/20 and 20/10. For example, for rb3 the relations 30/20 and 20/10 for lower sensitive penetrant (I1) reached factor 3 comparing with factor 2 for higher sensitive penetrant (I2). Some results of the comparison between the 3 sets (rb1, rb2, rb3) investigations are summarised in Table 1 with rb1 as a reference. T2 - 8th ECNDT CY - Barcelona, Spain DA - 2002-06-17 PY - 2002 UR - http://www.ndt.net/article/ecndt02/199/199.htm VL - 8 SP - 1(?) EP - 5(?) PB - European Federation for Non-Destructive Testing CY - Barcelona AN - OPUS4-1396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stadthaus, Meinhard A1 - Prokhorenko, P. A1 - Migoun, N. T1 - Physikalische Grundlagen des Eindringverfahrens N2 - Das Eindringverfahren ist in der Praxis weit verbreitet und gilt als sehr einfach in der Anwendung. Fachleute sind sich jedoch darüber im klaren, daß es sich bei diesem Verfahren um, höchst komplexe physikalische Vorgänge handelt und daß die zuverlässige Prüfung in vielen Fällen ein hohes Maß an Kenntnis der Zusammenhänge und Sorgfalt bei der Durchführung verlangt. Zur Optimierung der Anwendung und Weiterentwicklung der Prüfmittelsysteme ist eine quantitative Beschreibung der Eindringprüfung erforderlich. Die Grundlagen des Verfahrens werden zum ersten Mal umfassend in dem hier vorgestellten Buch behandelt, daß in Kürze bei der DGZfP erscheinen wird. In ihm wird von den mikrohydrodynamischen Phänomenen ausgegangen (z.B. Oberflächenspannung, Kapillarwirkung, Diffusion) und die Vorgänge auf der Grundlage von theoretischen und experimentellen Untersuchungen dargestellt. Dabei handelt es sich im Prinzip um die Dynamik des Eindringmittels während der Prüfung. Beim Eindringvorgang interessieren die Einflüsse der nachzuweisenden Inhomogenitäten, also der Typ (Durchgangsloch, Sackloch), die Form (Zylinder, Spalt mit parallelen oder konischen Wänden) und die Abmessungen der Fehler. Der Entwicklungsvorgang wird durch den Austritt des Eindringmittels aus dem Fehler und der anschließenden Ausbreitung in der Entwicklerschicht gekennzeichnet. Der zeitliche Ablauf der Anzeigenbildung wird im Wesentlichen durch die Eigenschaften der Entwicklerschicht bestimmt. Von besonderer Bedeutung ist z.B. der Einfluß des Lösungsmittels beim Naßentwickler. In weiteren Abschnitten werden der visuelle Nachweis der Anzeigen in Abhängigkeit von den Betrachtungsbedingungen dargestellt und Entwicklungstendenzen des Verfahrens aufgezeigt. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 1999 CY - Celle, Deutschland DA - 1999-05-10 KW - Eindringprüfung KW - Materialprüfung PY - 1999 UR - http://www.ndt.net/abstract/dgzfp99/data/p30.htm SN - 3-931381-27-7 VL - 2 IS - 68 SP - 765 EP - 772 PB - DGZfP CY - Berlin AN - OPUS4-719 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -