Study on Fatigue Strength of Lean Duplex Stainless Steel Base Metal

Abstract

This paper shows fatigue strength of lean duplex stainless steel base metal. Lean duplex stainless steel is inexpensive by reducing the rare element Ni and has higher tensile strength than that of SUS304. In this study, fatigue tests were carried out using smooth base metal test specimens made from steel plates of SUS323L, SUS821L1 and SUS304. As a result, fatigue strength of lean duplex stainless steel is higher than that of SUS304 as static strength increases when the stress ratio is zero. In addition, fatigue strength at two million cycles in case of the stress ratio with 0.3 is smaller by at least 80 MPa than that with the stress ratio of zero. Then, from obtained test data, a fatigue design curve applicable to lean duplex stainless-steel base metal is proposed.