Acoustic events detected during tensile testing of TWIP steels G. Por110, G. Csicso13, Z. Danka13, G. Gardonyi12, G. Manhertz1,23, P. Bereczki14, V. Szombathelyi1, P. Trampus117, B. Vero1 1aHungarian Acoustic and Industrial Diagnostic Laboratory bGleeble Laboratory; University of Dunaujvaros (DUF)15, Dunaujvaros, Hungary 2Budapest University of Technology and Economics11, Budapest, Hungary Acoustic Emission (AE), Modeling and Simulation, signal processing, materials characterization, material testing, Acoustic emission, TWIP steel
Twinning induced plasticity (TWIP) steels have a relatively short history of about 16 years only. These austenitic steels are used widely in many applications because of their excellent strength and ductility combined with good wear and corrosion resistance. The tensile curve of these steels has three well distinguished parts: in the first stage mainly dislocations cause the acoustic emission (AE) events; in the second stage the interactions of dislocations and twinning processes produce the majority effect in AE; while in the third stage twinning pairs are producing AE events. Our aim was to find differences in the AE events in different sections of hardening rate in these materials which have more and more importance in automotive industry. Differences were found in magnitudes, in the rate of events in the three stages, while general spectrum components were very similar to each other. Nevertheless we investigated also small differences in spectra as well, since they are important in classification of processes during treatment. Measurements were carried out using Gleeble simulator, which allowed performing tensile tests at different temperatures as well. Traditional AE parameters have been estimated with a new AE system developed by our laboratory.