In this study, mechanical and fatigue properties of the duplex (austenitic-ferritic) stainless steel wire (SSW) after drawing were invesitigated and compared with SUS304 SSW.
Further, the notch samples were made with the duplex SSW after drawing, and a fatigue crack generated at the notch root was observed by means of SEM after interruption of test at halfway.
The main results are as follows:
1) The duplex SSW after drawing shows the excellent fatigue and toughness properties as compared with SUS304 SSW.
2) Stress concentration at the fatigue crack tip is relaxed by the α phase that has low strength when fatigue crack propagate and propagation of fatigue crack is arrested by the γ phase that has high strength. From this result, maximum fatigue strength of the duplex SSW might be attained, if it has proper volume fraction as a microstructural component.