Abstract:

In this study, steel samples containing 1.2% carbon were produced at different unidirectional pressing pressures of 400 MPa and 800 MPa by Powder Metallurgy method. The produced samples were sintered at 1200˚C for 20 minutes in a vacuum atmosphere. After measuring the green density and hardness values of the sintered samples, the phase volume ratios and pore amounts were calculated. After these processes, the samples were austenitized at 850˚C for 5 minutes, then immediately subjected to quenching, accordingly a martensitic structure was obtained. Tempering heat treatment was applied at 200˚C, 400˚C and 600˚C to improve the hard and brittle properties of the martensitic structure. The effect of heat treatment and pressure differences on the microstructure and hardness value of the material was investigated. As a result of these examinations, as the pressing pressure increased, the density of the sintered samples increased and accordingly, the pearlite volume fraction was higher at 800 MPa pressure, while the porosity amount decreased. Due to the effect of the porosity amount on the mechanical properties of the samples produced by powder metallurgy, the hardness values of the samples with a pressing pressure of 800 MPa were higher than the samples exposed a pressing pressure of 400 MPa, which underwent the same heat treatment.