In this work, a 400 W Nd-YAG laser has been used to expose eight ferritic-pearlitic railroad steels to two different kinds of oscillating temperature cycles. Severe heating and water quenching cycles were chosen to test the materials thermal shock resistance. Their thermal fatigue behaviour has been tested in a laser pulse induced way. The results obtained from laser-tests show that improving the thermal shock resistance of any railroad steel requires opposite materials properties to those for improving its thermal fatigue resistance. Dependent on the severity of the temperature gradients, contrary connections between microstructure, material properties and thermal shock or fatigue resistance were obtained. This results were explained on the basis of the micromechanisms. It has further been shown that a high crack density on the surface of a material does not represent the crack propagation into the depth. Therefore, the evaluation of the material damage has to be carried out carefully. In conclusion, the laser test system serves a couple of possibilities to simulate the material behaviour under changing working temperatures. Nevertheless, the selection of a material with optimum thermal stress resistance can be a complex task.
Nd-YAG-laser simulated thermal shock and thermal fatigue behaviour of railroad steel
Vd-YAG-Laser-Simulation des Thermoschock- und des thermischen Ermüdungsverhaltens von Radreifenstählen
Metall - Internationale Fachzeitschrift für Metallurgie ; 52 , 7-8 ; 464-470
1998
7 Seiten, 15 Bilder, 3 Tabellen, 16 Quellen
Article (Journal)
English
legierter Stahl , mechanische Eigenschaft , chemische Zusammensetzung , Härte , Streckgrenze , Zugfestigkeit , Bruchdehnung , Brucheinschnürung , Temperaturwechselbeständigkeit , Rissbildung , Rissausbreitung , Materialermüdung , Lebensdauer , Eisenbahnrad , Reifen (Ring) , Werkstoffgefüge , Simulationsmodell
Laser thermal shock and fatigue testing system [3097-60]
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