Research of fundamental mechanical properties of carbon and low-alloy steels

In this study, the optimization of the microstructure and mechanical propertieswhich effect the fracture toughness of carbon and low-alloy steels areinvestigated. The relationships among the fracture toughness, microstructure andmechanical properties for heat treatment processes are considered.Mechanical experiments (uniaxial tensile test and charpy test) are carried out forthe specimens which were applied various heat treatment. The effect of dataobtained from the experiments (yield strength, tensile strength, true fracturestrength, shrinkage, strain hardening coefficient, charpy toughness) on the fracturetoughness are discussed. In addition, the relationships between microstructuresobtained from SEM (scanning electron microscope) and optical microscope andmechanical experimental data are explained.In the result of this study, the heat treatment processes under Ac3 line in iron-cementite phase diagram can be stated to increase the fracture toughness of steelsused in the study.Keywords : Heat Treatment, Mechanical Properties, Fracture Toughness, StrainHardening, Microstructure.