Alteration of the Elastic Properties of Steel and （改变的弹性,钢铁和）.pdfVIP

1st International Symposium on Laser Ultrasonics: Science, Technology and Applications July 16-18 2008, Montreal, Canada Alteration of the Elastic Properties of Steel and Cast Iron Caused by Hardening Bernhard REITINGER 1, Thomas BERER 1, Oliver HELM 1, Peter BURGHOLZER 1 1 Upper Austrian Research, Department of Contactless Sensor Technology, Hafenstrasse 47-51, 4020 Linz, Austria; Phone: +43 (0) 732-9015-5643, Fax +43 (0) 732-9015-5618; e-mail: bernhard.reitinger@uar.at, thomas.berer@uar.at, oliver.helm@uar.at, peter.burgholzer@uar.at Abstract Generally, the elastic material properties (e.g. Young’s modulus and Poisson ratio) in steel and cast iron are assumed to be unaffected by hardening processes in common literature. Only the hardness is presumed to alter, while the elastic properties keep constant. As the results of traditional and FEM (finite element method) static and dynamic stress calculations directly depend on the accuracy of these properties - they are highly crucial. We show that the elastic properties get considerably modified during the hardening process. The change in Young’s modulus was up to 4%. An increase in hardness was associated with a decrease of the Young’s modulus. This effect was measured in steel alloys, as well as in cast iron. Measurements were performed utilizing a picosecond-laser and a photorefractive interferometer. Subsequently, the elastic properties were calculated from the recorded signals and the known density of the materials. As the measurements are performed contactless, future measurements will be done during the hardening process to get more detailed information on the recryst