Abstract Inside a research program agreed with the AIAS-MEAS Energy Methods Group, this preliminary study starts defining the fatigue parameters of a commercial steel in static and cyclic loading conditions. The final purpose of the research is to define the fatigue limits in different loading conditions using different energetic methodologies and comparing them with those derived by several tests performed by the other researchers of the Group. This first step was carried out using the thermographic methods already proposed in literature, determining the values of the fatigue limit for R=0. At the same time, the thermal response in static tests were derived in order to correlate the limit of the totally thermoelastic behavior, corresponding with the phase of the crack nucleation, with the fatigue limit.