Lcf loop shape in near pearlitic steels – influence of temperature
Paper i proceeding, 2013

Specimens of near pearlitic railway wheel steels have been exposed to isothermal, uniaxial low cycle fatigue tests at constant total strain amplitudes from 0.4 – 1.0%. Temperatures have been varied from -60°C to 500°C. The data recorded has been analysed by fitting polynomial expressions to different parts of the loop. A technique used for extracting the unloading stiffness was presented at the previous conference, LCF6 in Berlin 2008. This procedure has now been extended to characterize the entire loop. The degree of micro plasticity and its effect on unloading stiffness, the strain energy and the cyclic stress development have been characterized. An increased cyclic hardening during the main part of the fatigue life was identified on cycling at 300°C at total strain amplitude of 0.6%. At 500°C the viscous behaviour dominates over the cyclic strain hardening yielding decreasing stress amplitude.

unloading stiffness

LCF loop shape

cyclic softening

hysteresis loop analysis

micro plasticity

temperature effects


Johan Ahlström

Chalmers, Material- och tillverkningsteknik, Materialteknologi

Proceedings of 7th International Conference on Low Cycle Fatigue, Aachen, Germany, September 9–11, 2013






Grundläggande vetenskaper


Annan materialteknik