Improvement of formability and tensile mechanical properties of SAE 970X steel by controlled rolling process

Abstract

It is believed that texture, as the preferred crystallographic orientation of microstructural features, causes plastic anisotropy, leading to a decrease in formability. Thus, promoting recrystallization and randomizing crystallographic texture have been the main methods of increasing formability. The aim of the current study was to improve the tensile properties and formability by means of controlling the microstructural features under controlled rolling processes in an SAE 970X steel. The evolution of microstructure, crystallographic orientation, and grain boundary distribution was analyzed by scanning electron microscope, X-ray diffraction, and electron backscatter diffraction. The results of tensile uniaxial tests and equibiaxial tension behaviors showed that the ultrafine ferrite grains oriented along the {011} and {111} planes parallel to the rolling direction, with adequate slip systems accompanied by the dispersion of martensite/austenite (M–A) microconstituents in the ferritic structure, improved the tensile mechanical properties and formability. The sample subjected to isothermal rolling at 850 ◦C achieved successful results compared to as-received and other controlled rolling methods.