The effects of alloying elements and sintering temperature on microstructure and mechanical properties of steels produced by powder metalurgy

In this study, Distaloy AE powder was used and low alloyed steels consisting Fe-Ni-Cu-Mo-C were produced. The study were carried out in two stage. In the first stage, 505 distaloy steel powder was compacted with pressure of 700 MPa and then sintered at various temperatures (1120,1150 and 1200 oC) in nitrogen+% 4 H2 atmosphere for 30 minutes. The samples were cooled in different environment such as in air, oil and water. At the second stage of the study alloying, elements of ferro-boron, molybdenum and copper were added into the starting powders of 505 distaloy. The compacting pressure, sintering atmosphere and duration were the same with those used in first stage. Sintering temperature was selected as 1200 °C. The samples were cooled in different environment. The effects of different sintering temperature, cooling rate and chemical composition on the microstructure and mechanical properties of steels produced by powder metallurgy (PM) method were examined.Microstructural characterization techniques such as optical microscopy, scanning electron microscopy (SEM) SEM/EDS, line analysis and XRD were used for microstructural examination. On the other hand, hardness and wear behavior of the sintered steels were investigated. Sintering temperature, cooling rate and chemical composition on the microstructure and mechanical properties were affected. Hardness and wear resistance were increasing with increasing of the sintering temperature and cooling rate. Chemical composition has great influence on the hardness and wear behavior. Hardness and wear resistance of the sintered metal were increased with the addition of molybdenum and copper addition. Boron addition showed negative influence on those properties mentioned above. Mechanical values obtained in the experimental tests were correlated with microstructure of sintered steels.