Sinterability and tensile properties of nickel free austenitic stainless steel X15 CrMnMoN 17 11 3

摘要

Nitrogen absorption during sintering of nickel free austenitic stainless steel X15CrMnMoN 17 11 3 changes its sinterability, affecting final dimensions, density, microstructure and tensile properties. Sinterability was analysed using alloy phase diagram combined with experimental results for linear shrinkage factor, density and microstructure. Tensile tests were performed using standard tensile tests specimens used in powder metallurgy (ISO 2740). The sintering was performed at 1200 °C and 1265 °C temperatures, in argon (Ar) and nitrogen (N2) atmospheres, with the partial pressures between 400 mbar and 800 mbar. Sintering times between 3 h and 6 h were used. Lack of nitrogen, for parts sintered in argon atmosphere, resulted in final microstructure consisting of ferrite and austenite. Presence of ferrite during sintering caused better sinterability compared to parts sintered in nitrogen atmosphere, where austenitic microstructure was formed. It was found that increasing of nitrogen partial pressure causes strengthening of steel and increasing nitrogen content, while reduces density and shrinkage factor. Reduced ductility of steel after sintering was improved using solution annealing.