Producing nanostructured 304 stainless steel by rolling at cryogenic temperature

Effect of rolling temperature on deformation-induced α′- martensite and reverted austenite was investigated. Rolling experiments were carried out at room temperature (without inter-pass cooling) and at liquid nitrogen temperature, respectively. The phase components, orientations, and microstructures are characterized by X-ray diffraction, electron backscattered scattering detection, and transmission electron microscopy. The (200)α′ martensite was found to be of the preferred orientation in sample rolled at cryogenic temperature. An average grain size of about 300 nm combined with high yield strength (∼1500 MPa) and good elongation (∼35%) was obtained by the cryogenic temperature rolling and 240 s annealing treatment.