Specific features of α → γ transformation in powder carbon steels

A study was made into the influence of sintering conditions on phase transformations in carbon powder steels of various density with carbon content ranged of 0.34 to 0,41 %. Powder mixture pressing at 500 and 800 N/mm2 with subsequent sintering in hydrogen at 1100-1200 deg C for 1-4 h resulted in preparation of samples with relative density of 80-88 %. Thermal differential analysis and kinetic curves of austenization and lattice parameter variation testify to the fact that under conditions mentioned the metastable austenite is formed and crystal defects play an essential role in its formation. 5 refs., 3 figs., 2 tabs