Effect of High-Temperature Thermomechanical Treatment on the Structure, Mechanical Properties and Corrosion Resistance of Austenitic-Ferritic Steel with Varying Rare Earth Metal Content

The structure, mechanical properties, nonmetallic inclusion cleanliness and pitting corrosion resistance of S32750 duplex stainless steel microalloyed with the rare‑earth metals Ce + La in amounts of 0.02–0.08 wt % were investigated after high‑temperature thermomechanical treatment (HTMT) with different numbers of passes during hot rolling, and compared with standard heat treatment. The best combination of properties was obtained for the steel containing 0.05 wt % REM and processed by HTMT with single‑pass deformation: conventional yield strength—561 MPa; tensile strength—857 MPa; total elongation—30%; pitting resistance potential—1.254 V.