Effect of Low Annealing Temperature and Reversion of Α’-Martensite on the Mechanical Behavior and Texture of a 2304 Lean Duplex Stainless Steel

The effects of cold rolling, leading to formation of α’-martensite and its subsequent reversion during annealing treatment, were analyzed on the microstructural evolution and mechanical properties of a LDSS 2304. For this purpose, 4 mm thick hot-rolled sheets were cold-rolled up to a thickness of 1 mm, followed by isochronal annealing from 400°C to 600°C for 1800 s. In this range of temperature, 475°C, embrittlement may have occurred, leading to a rise of microhardness and a decrease of PREN (Pitting Resistance Equivalent Number) in ferrite. The X-ray diffraction (XDR) technique was employed to quantify the phase volume fraction. The texture was analyzed through ODF (Orientation Distribution Function). After tensile test, all samples had a brittle fracture due to the low reversion of α’-martensite. Increasing temperature enhanced the softening and ductility but decreased yield and tensile strengths of the specimens.