Mechanical properties of a novel high nitrogen and low nickel stainless steel S35657

Abstract

Stainless steel exhibits excellent ductility and corrosion resistance, making it highly promising for applications in civil engineering. In order to investigate the mechanical properties of a novel stainless steel S35657, a total of 150 coupons including 125 plates and 25 rods were tested. The failure modes, stress-strain curves, and mechanical parameters of coupons were obtained. Fractographic analysis using scanning electron microscopy was also performed to investigate the failure mechanisms. It was found that all coupons exhibited ductile failure mode with elongation up to 52.08%. The nominal yield strength standard value reached 370.50 MPa, while the ultimate tensile strength standard value reached 736.07 MPa. The various existing typical constitutive models were assessed, indicating that these models provide a good fit in the elastic stage but are not applicable in the hardening stage. Based on the Ramberg-Osgood model and test results, a new constitutive model applicable to stainless steel S35657 was proposed. Moreover, a design reliability analysis was carried out using the Equivalent Normalization Method (JC method), and partial factors for resistance of stainless steel S35657 were calibrated, which were 1.05 under windless load combinations and 1.15 under windy combinations.