TY - CONF A1 - Puthiyaveettil, N. A1 - Krishna, S. A1 - Kidangan, R. A1 - Unnikrishnakurup, Sreedhar A1 - Krishnamurthy, C. V. A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Balasubramaniam, Krishnan T1 - In-line laser thermography for crack detection at elevated temperature: A Numerical modeling study T2 - QIRT 2016 N2 - The detection and characterization of cracks prior to damage is a technologically and economically highly significant task and is of very importance when it comes to safety-relevant structures. The evaluation of a components life is closely related to the presence of cracks in it. Laser thermography has already high capability for the detection of surface cracks and for the characterization of the geometry of artificial surface flaws in metallic samples. Crack detection in metallic samples at high temperature is highly significant in present manufacturing scenario. During the casting process of billets, surface cracks form, due to the suboptimal cooling rates. These cracks reduce value of the billet and must be removed using machining process after cooling. This secondary process increases cost of manufacturing. In this work we developed a heat transfer model for laser thermography to study the thermal contrast variation with increase in surface temperature using finite element method (FEM). Here we are mainly concentrating the capability of the scanning laser thermography in crack detection which are in elevated temperature and numerical modeling study of thermal contrast variation of crack with respect increase in metal surface temperature. This study is important to prove the capability of laser thermography for crack detection in elevated temperature. Since we are using High power CW Laser to local heating of the metal surface which can give relatively high thermal contrast even at elevated temperature compare to other heating source. Here we are modeled and simulated 2D laser scanning across a surface breaking crack and developed an algorithm to produce the vicinity of crack. The algorithm we developed applied for various surface temperature data. And validated the credibility of the algorithm with experimental data. T2 - 13th Quantitative Infrared Thermography Conference 2016 CY - Gdansk, Poland DA - 04.07.2016 KW - Thermal contrast KW - Laser thermography KW - Thermography KW - Surface cracks KW - Elevated temperatures KW - FEM PY - 2016 UR - http://www.ndt.net/article/qirt2016/papers/092.pdf DO - https://doi.org/10.21611/qirt.2016.092 VL - 2016 SP - 588 EP - 596 PB - QIRT 2016 Proceedings AN - OPUS4-39105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Polomski, Benjamin A1 - Myrach, Philipp A1 - Le Claire, Elisabeth A1 - Unnikrishnakurup, Sreedhar A1 - Vengara, N. A1 - Balasubramaniam, Krishnan A1 - Ziegler, Mathias T1 - Thermographic crack detection in hot steel surface N2 - The detection and characterization of surface cracks in steel specimens prior to damage is a technologically and economically highly significant task and is of utmost importance when it comes to safety-relevant structures. In steel production where steel billets at high temperatures have to be inspected while moving a number of well-established NDT methods cannot be applied. Laser thermography however is a promising candidate to serve as a fast, non-contact and remote tool in this case. We present a study that shows that the crack detection capabilities of laser thermography can be extended also to specimens at high temperature. A combination of inductive and laser heating allows to systematically study the contrast formation as well as the optimization of the important measurement parameters. The experiments are accompanied by FEM simulations that provide a better insight of the physical correlations and support the experimental developments. The aim of these studies is to develop a system with high inspection speed and detection performance to be in-line operated under the hostile environment of steel production lines. T2 - 19th World Conference on Non-destructive Testing (WCNDT) CY - Munich, Germany DA - 13.06.2016 KW - Laser thermography KW - Non-destructive testing KW - Induction heating PY - 2016 AN - OPUS4-36813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -