Effect of Cooling Media and Tempering Temperature on the Mechanical Properties of Reinforcement Steel

摘要

The object of this research is study the effect of cooling media and temperature on the mechanical properties for reinforcement steel which is tempering used in concrete at explosive and burning building. Many mechanical tests like tensile, hardness impact test, and microstructure to the samples at different temperature (900,600,400)°C were carried out. The samples were subjected to different heat treatment (Normalizing, hardening, Periodization, Recrystallization Annealing) and compared the results with samples without heat treatment. The results shows effect of presence of martensite in the samples which is heated to (900)°C and quenching in Water increasing in values of hardness and decreasing impact and tensile for found martensite at room temperature. At heating (600)°C show the hardness decreased, but the tensile down at quenching in Water and increase at normalizing. At heating (400)°C show the hardness increases at quenching, the tensile strength increase at quenching and decrease at normalizing, the impact test is down in general. In the hardening heat treatment process, this deals with quenching and tempering. At quenching outer surface is cooled quicker than the center so the transformation of the austenite is proceeding in microstructure at different rates. Optical Microscopy results showing at (900)°C and hardening or normalizing the microstructure produced (Fe3C+M) in the different percentage. The spheroidized structure is desirable when minimum hardness maximum ductility, at normalizing occurring remove the residual stress and distrpution of carbide, at (400)°C and quenching produced (Fe3C) has large size in (α+P) base, at normalizing occurring distribution of carbide.