This document summarizes a study on the effect of heat treatment on the microstructure and mechanical properties of medium carbon steel. Two grades of steel were tested, one with copper and one without. Samples underwent various heat treatments including annealing, normalizing, quenching, and tempering at different temperatures. Hardness, ultimate tensile strength, and ductility were then measured. Results showed that steel with copper had higher hardness and strength but lower ductility. Hardness and strength decreased with increasing tempering temperature, while ductility increased. The study provides data on the mechanical properties and microstructure of heat treated medium carbon steel.