Crack initiation at intermetallic inclusions in spring steels under close to real loading conditions
Abstract
Material fatigue is a damaging process caused by cyclic loading, i.e. repeated loading and unloading. Great numbers of load cycles can lead to the formation of cracks and ultimately fracture although all loads are significantly below the static strength of the material. Material fatigue is one of the most frequent reasons for failure of technical components and studying this process of material degradation is therefore of great technical as well as economical interest. There is a recently increasing interest in the fatigue performance of materials when very high numbers of load cycles are applied. Both the demand for reduction of environmental impact and the quest for enhanced economic efficiency are driving the design of new components and systems towards extreme fatigue lives. Appropriate selection of the used material and adequate design of the components must guarantee safe operation even after very long service times. BOKU and KOBE STEEL have a common scientific interest in understanding the Very High Cycle Fatigue (VHCF) properties of materials under close to real conditions. Mechanisms leading to VHCF failure must be understood and appropriately characterized, described, and modelled for purposive development of materials as well as for the safe design of components. High strength steels are high performance materials that are frequently used in applications where a large number of high cyclic stresses occur during service. Therefore, the VHCF properties of high strength steels have been subject to several investigations during the past 15 years. The project serves to study the role of microstructural variability, notably the effect of non-metallic inclusions, on crack initiation, initial crack growth and associated fatigue lifetime. Investigations of spring steel will be performed under loading conditions, that are typical for loading conditions of coil springs used in transportation industry.
keywords material fatigue
Publikationen
Project staff
Herwig Mayer
Ao.Univ.Prof. Dipl.-Ing. Dr.techn. Herwig Mayer
herwig.mayer@boku.ac.at
Tel: +43 1 47654-89202
Project Leader
01.07.2017 - 30.09.2018