Corrosion resistance of sintered duplex stainless steels in the salt fog spray test

This paper presents corrosion resistance results in salt fog spray test of duplex stainless steels obtained through powder metallurgy starting from austenitic X2CrNiMo 17-12-2, martensitic X6Cr13 powders by controlled addition of alloying elements in the right quantity to obtain the chemical composition of the structure similar to biphasic one. In the preparations of mixtures the Schaffler's diagram was taken into consideration. The prepared mixtures of powders have been sintered in a vacuum furnace with argon backfilling. After sintering two different cooling cycles were applied: rapid cooling with an average cooling rate of 245 °C/min using nitrogen under pressure 0.6 MPa and slow cooling with furnace with an average cooling rate of 5 °C/min in argon atmosphere. The corrosion properties have been studied through salt fog spray test which is applied by the automotive industry end-users because it reproduces the behaviour of a material in front of the environmental corrosion with feasibility. According to the achieved results, it was confirmed that the applied sintering method as well as powder mixtures preparation allows for manufacturing the sintered duplex steels with good corrosion properties in chloride environment.