Abstract
Powder mixes containing up to 4 % Mn with 0.3 or 0.7 % C, balance Fe, were compacted to green densities ranging from 7.0 to 7.1 g•cm^-3 and sintered in atmosphere of N₂/H₂ in laboratory and industrial furnaces at temperatures of 1120–1200°C and dew points ranging from -60 to -23°C. Sinter-hardening was also investigated. All the alloy microstructures were heterogeneous, consisting of diffusive and non-diffusive transformation products and additionally ferrite and retained austenite. The best combination of mechanical properties for the industrially sintered furnace-cooled state, yield, tensile and bend strengths of 438, 580 and 1136 MPa, with tensile strain of 1.12 %, was achieved for Fe-2Mn-0.7C alloy. Sinter-hardening led to an improvement in mechanical properties: for Fe-4Mn-0.3C alloy the yield, tensile and bend strengths were 570, 664 and 1263 MPa, respectively, at acceptable impact energy of 14 J, with tensile strain of 0.52 %. Many of the results compare favourably with the requirements of MPIF 35 for medium strength structural parts.

Key words
manganese sintered steels, microstructure, mechanical properties

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