Effect of precipitation on hot formability of high nitrogen steels

This paper examines the effect of precipitation on hot formability of high nitrogen steels (HNSs) through modeling of the precipitation and experimental simulation of the hot deformation. The experiments were carried out on three grades 1.4501, 1.4882, 1.4452 of HNSs and austenitic grade 1.4301 steel. In the course of modeling, precipitation characteristics and phase transformations were investigated by calculation of phase diagrams and precipitation analysis using SEM/EDX. High temperature properties were determined at deformation temperatures between 900 °C and 1300 °C using hot tensile tests in order to investigate the hot formability. The effect of deformation temperature on crack sensibility was determined using compression test. The effects of carbide/nitride precipitation on hot formability in HNSs were discussed.

Research highlights▶ Hot deformation is critical for HNSs 1.4882 and 1.4452. The precipitates of M2N are stable at deformation temperatures in steel 1.4452. Hardly soluble M(C,N) precipitates reduce the hot ductility of HNS 1.4882. Super duplex steel 1.4501 shows similar deformability to reference steel 1.4301.