Authors
Juha Uusitalo, Pentti Karjalainen, Delphine Retraint, Mikko Palosaari,
Title
Fatigue properties of steels with ultrasonic attrition treated surface layers
In
Materials science forum
Volume
604-605
Pages
239–248
Publisher
scientific.net
Year
2009
Publisher's URL
scientific.net
Indexed by
Abstract
Severely deformed surface layers have been created by ultrasonic attrition technique on four steel sheets to investigate their influence on fatigue behaviour. A low-carbon (0.05%) ferritic steel and a medium-carbon (0.47%) normalized ferritic-pearlitic steel were selected to study the effect of carbon content on fatigue properties of carbon steels. Two stainless steels, Type 316L and Type 301LN, were also tested to study the influence of stability of the austenitic structure. Microstructural features were characterized by hardness measurements, X-ray diffraction and optical and electron microscopy. Fatigue properties were determined in flexural bending in the range 104 to 107 cycles. Crack nucleation and propagation stages were followed. In the attrition treatment thin severely deformed surface layers were found to form. Highly increased hardness was measured in these layers, especially for stainless steels, where also strain-induced martensite was formed. Drastic improvement in fatigue resistance was observed for all steels due to the surface nanocrystallization treatment.
Affiliations
Offprint