Austenitic-ferritic (duplex) stainless steels are successfully used in chemical, nuclear, oil and gas industries, due to their good mechanical properties and excellent generalized and localized corrosion resistance in many environments and operating conditions (for example, chloride induced stress corrosion). The aim of this work is the analysis of the fatigue crack propagation resistance in air of three austenitic-ferritic stainless steels: - a "lean" duplex stainless steel 21 Cr 1 Ni; - a "standard" duplex stainless steel 22 Cr 5 Ni; - a "superduplex" stainless steel 25 Cr 7 Ni. Two different heat treatments were considered: - solution annealed 1050C for 1 h (as received; R = Kmin/Kmax = 0.1; 0.5; 0.75) - tempering at 800C up to 10 h (only R = 0.5) A scanning electron microscope (SEM) fracture surface analysis has been performed to investigate the fatigue crack propagation micromechanisms in the investigated superduplex stainless steel. Experimental results allow to evidence the influence of secondary phases, carbides and nitrides on fatigue crack propagation resistance that depends on the duplex stainless steel chemical composition.
Fatigue crack propagation micromechanisms in high temperature embrittled duplex stainless steels / F., Iacoviello; V., Di Cocco; E., Franzese; Natali, Stefano. - STAMPA. - 3:(2008), pp. 2275-2282. (Intervento presentato al convegno 17th European Conference on Fracture 2008: Multilevel Approach to Fracture of Materials, Components and Structures, ECF17 tenutosi a Brno; Czech Republic nel 2 September 2008 through 5 September 2008).
Fatigue crack propagation micromechanisms in high temperature embrittled duplex stainless steels
NATALI, Stefano
2008
Abstract
Austenitic-ferritic (duplex) stainless steels are successfully used in chemical, nuclear, oil and gas industries, due to their good mechanical properties and excellent generalized and localized corrosion resistance in many environments and operating conditions (for example, chloride induced stress corrosion). The aim of this work is the analysis of the fatigue crack propagation resistance in air of three austenitic-ferritic stainless steels: - a "lean" duplex stainless steel 21 Cr 1 Ni; - a "standard" duplex stainless steel 22 Cr 5 Ni; - a "superduplex" stainless steel 25 Cr 7 Ni. Two different heat treatments were considered: - solution annealed 1050C for 1 h (as received; R = Kmin/Kmax = 0.1; 0.5; 0.75) - tempering at 800C up to 10 h (only R = 0.5) A scanning electron microscope (SEM) fracture surface analysis has been performed to investigate the fatigue crack propagation micromechanisms in the investigated superduplex stainless steel. Experimental results allow to evidence the influence of secondary phases, carbides and nitrides on fatigue crack propagation resistance that depends on the duplex stainless steel chemical composition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
