Fatigue behaviour of sintered duplex stainless steel

The stainless steel despite of tradition of use over the 100 years are steel interesting in terms of metallurgical improvement and development of new products. Stainless steel products undergo intensive development, especially for duplex stainless steel grades manufacture be conventional casting method and metal forming processes, thus, influences an increase in the interest of those materials by alternative technologies of metal forming, which is powder metallurgy. The powder metallurgy and manufacturing processes of metal powders and sintered components production undergoing rapid development. This trend applies also for sintered duplex stainless steels. The paper investigates fatigue behaviours of vacuum sintered duplex stainless steel produced by mixing in appropriate proportions powders of ferritic and austenitic stainless steel and elemental alloying powders and then sinter hardening in a vacuum. The mechanical properties of studied steel were evaluated in terms of tensile strength, hardness, toughness, plasticity. Fatigue tests were carried out in symmetric plane bending at stress ratio R= -1 with frequency of about 24Hz. Fatigue crack propagation micromechanisms were investigated by means of a scanning electron microscope fracture surface analysis. (C) 2014 Elsevier Ltd.