Influence of Annealing, Normalizing Hardening Followed By Tempering And Laser Treatments on Some of The Static and Dynamic Mechanical Properties of Medium Carbon Steel
Dr. AbdulKhaliq F. Hamood , Dr. Sanna A. hafeed
Abstract

This research illustrates the influence of different heat treatments on the mechanical properties such as stress-strain curves ,wear resistance and fatigue properties of medium carbon steel,. This steel was treated by annealing, normalizing, hardening followed by tempering and laser treatments. The bulk mechanical properties of ultimate ,fracture and yield tensile strength were evaluated. Surface mechanical properties of fatigue, wear resistance and hardness were evaluated as well. Microstructure of treated alloys also were inspected. Results showed that (hardened -tempered) steel had improved tensile strength, fatigue{limit, life}, wear resistance, hardness then laser surface treated alloy, then the normalized alloy came in order ,but annealed alloy had the lowest mechanical properties. Annealing caused softening and growth of alloy structure. It was found that the microstructure of treated alloy play an important role in the improvement or deterioration of bulk and surface mechanical properties and by analyzing the obtained results. For (Quenched -tempered) alloy found fine tempered martensititic structure, laser surface treated alloy had martensititic structure in the skin and ferritic- pearlitic structures in the core .Normalized alloy had ferriticpearlitic structures, Annealed alloy had coarse ferritic- pearlitic structures
Keywords: Heat treatments, fatigue, medium Carbon Steel, quenching, normalizing, laser treatment.