Acero inoxidable dúplex lean fatigado a temperatura ambiente

RENATA STRUBBIA; SILVINA HEREÑÚ; IRIS ALVAREZ-ARMAS

Rosario

Conferencia; 5ª CONFERENCIA SOBRE USOS DEL ACERO DEL IAS; 2010

Instituto Argentino de Sidururgia

Though about 80 years have passed since the first discovery of duplex stainless steels (DSS) they are still under development. Nowadays, a way to reduce the cost of DSS is to decrease the content of the most expensive alloy components: nickel and molybdenum. These new DSS are called Lean (DSSL). In recent years there has been sustained activity towards improving substructural characterization and corrosion properties of Lean DSS. However, scarce work has been found on their mechanical properties in literature and particularly no information is available on their fatigue behaviour. Therefore, the purpose of this investigation is to analyze the cyclic behaviour at room temperature of DSSL AL 2003 (UNS S32003) and LDX 2101 (UNS S3210) at different total strain ranges. The fatigue dislocation structure was analyzed by a transmission electron microscopy (TEM). Thegeneral cyclic behaviour of both DSSL is characterized by a small initial hardening followed by a softening stagethat becomes more pronounced with the increased of the applied strain range. For all the employed strain rangesDSSL AL 2003 attains higher stress level than DSSL LDX 2101. This fact could be attributed to the highermolybdenum content in DSSL AL 2003. Within the studied strain ranges it seems that the ferrite phase controlsthe cyclic behaviour in both DSSL and that the dislocation structure of this phase in LDX 2101 shows apremature evolution in relation with that observed in AL 2003.