Abstract: “Presented work discusses research results concerning the effect of the heat treatment process. Thermal fatigue which expresses repeated heating and cooling processes affect the ductility or the brittleness of the material. In this research 70 specimens of steel (1.5 mm thickness, 85 mm length, 32 mm width) are subjected to thermal fatigue at different conditions. Heating temperatures; Th = 100, 300 and 500 ° C. Number of repeated cycles; N =1 to 100. Results are evaluated then compared to each other and to that of specimens without subjected to thermal fatigue.”

Keywords: steel alloys, thermal analysis, heat treatment, hardness, thermal fatigue .