Precipitation phases at different processes and heat treatments as well as their effects on the mechanical properties of super-austenitic stainless steel

A new type 1Cr30Ni30Mo2TiZr super-austenitic stainless steel has been developed. The microstructures, precipitation phases and mechanical properties of the steel under different deformation processes and heat treatment (solution, stabilized treatment) were investigated using X-ray Diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) as well as mechanical tests. The results indicate that coarse carbides such as Cr-rich M23C6, sigma (sigma), and little chi (chi) phases were formed in the steel, and large alpha' -Cr phases were also detected at three joint grain boundaries, and they were promoted by large strain. The precipitate phases were dissolved or transformed to intermetallic phase even at higher elevated temperature, and influenced the mechanical property obviously. These intermetallic compounds seriously reduced elongation of the rolled steel at room temperature and 700 degrees C, but increased the forged one at 700 degrees C. Impact absorbed energies of the stabilized specimens were lower than half of that solution status.