The influence of sintering time on the properties of PM duplex stainless steel

Purpose: The purpose of this paper is to analyse the effect of sintering time on the pore morphology, microstructural changes, tensile properties and corrosion resistance of vacuum sintered duplex stainless steel. Design/methodology/approach: In presented study PM duplex stainless steels were obtained through mixing base ferritic stainless steel powder with controlled addition of elemental alloying powders and then sintered in a vacuum furnace with argon backfilling at 1250°C for different time periods. Produced materials were studied by LOM/SEM metallography and the pore morphology was characterized. The mechanical properties were studied in tensile, hardness and Charpy impact tests. The corrosion resistance was evaluated by means of salt spray test and immersion in sulfuric acid. Findings: Prolongation of sintering time influenced on increase of density thus on the mechanical properties and microstructure balance. Practical implications: Mechanical properties of obtained PM duplex stainless steels are very promising, especially with the aim of extending their field of possible applications. Originality/value: The possibility of obtaining balanced austenitic-ferritic microstructure of stainless steel using elemental powders added to a stainless steel base powder. The vacuum sintering of such powder mixture results in good microstructural homogeneity.