Effect of sintering temperature on the microstructures and properties of 30Cr powder metallurgy low alloy steel

30Cr powder metallurgy low alloy steel was prepared by gas atomization and hot-pressing sintering, and the effect of sintering temperature on the microstructures and mechanical properties of the obtained low alloys steel was studied and analyzed by scanning electron microscope (SEM), Rockwell hardness tester, and mechanical test machine at different sintering temperatures. The results show that, when the temperature increases in 1100~1200, the number of pores on the samp℃ le surface is decreased, the pore size is also getting smaller. The sample microstructures show the granular bainite, which are composed of sheet bar M/A island and polygon ferrite. With the increase of sintering temperature, M/A island gradually increases and grows, and the density, hardness, tensile strength, and yield strength of the sintered samples are continuously improved, which is related to the reduction of porosity in the sintered samples and the increase of hard M/A islands. However, as sintering temperature continues to rise to 1225, the sample℃ shows the oversinter phenomenon, the sample defects are emerged, such as holes, and the mechanical performance of sample appears degradation. When the sintering temperature is 1200, the℃ sample gets the optimal performance as the tensile strength and elongation of up to 1288 MPa and 12.52%, respectively.