Effect of medium carbon steel microstructure on tensile strength and fatigue crack growth

Purpose The purpose of this paper is to evaluate the effects of medium carbon steel microstructure on the tensile strength and fatigue crack growth (FCG) behavior. Design/methodology/approach To achieve this aim, four different heat treatment methods (normalizing, quenching, tempering at 300 degrees C and tempering at 600 degrees C) were considered. Microstructural evolution was investigated by scanning electron microscopy. FCG rate tests were conducted on the resultant microstructures with compact tension specimens at room temperature by a standard testing method. Findings The results show that the normalized microstructure had the largest number of cycles to failure, indicating a high fatigue resistance, followed by the as received, tempered at 600 degrees C, tempered at 300 degrees C and quenched microstructure. Originality/value The paper shows the influence of the microstructure on the fatigue-propagation behavior with the definition of the Paris parameters of each heat treatment condition.