Considering the importance of the mechanical properties of the materials in terms of engineering design, the work in question has the purpose of obtaining the mechanical property related to the area of fatigue, called the fatigue limit, using infrared thermography technique. This property was studied in SAE 1020 carbon steels by thermographic methods such as the Risitáno cyclic and static method and the Luong method. This study was carried out using cyclic compressive loads, whose stress ratios were equal to R = 2, R = 7.7, R= minus 3 and static loads. In total, nine tests were performed, of which six were cyclic, two static and one compressive. The buckling was also studied, considering the compressive nature of the loads used in the tests. All the results were compared among themselves and also compared to bibliographical references, continuing the line of research that has been developed in the Photomechanical laboratory of PUC-Rio.