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The effect of rolling parameters on microstructure and tensile properties of nanocrystalline/microcrystalline 304 stainless steel (SS) casted by the aluminothermic reaction was investigated in this work. It was found that majority of the nanocrystalline austenite of the 304 SS rolled at 700 ∘ C and 900 ∘ C grew up and transformed to sub-microcrystalline. While the nanocrystalline/microcrystalline structure still retained rolled at 900 ∘ C with 40% deformation followed 600 ∘ C with 70% thickness reduction, and microcrystalline austenite grains distributed evenly. The strength and ductility of the various rolled 304 SS were improved compared with the as-casted 304 SS steel. The steel rolled at 900 ∘ C with 80% deformation exhibited a uniform elongation as large as 31.3%, which is almost the same ductility level of counterpart coarse-grained steel. The rolled steel at 700 ∘ C with 80% deformation achieved the maximum tensile strength but the smallest elongation. The sample, two-step rolled at 900 ∘ C with 40% thickness reduction and then 600 ∘ C with 70% thickness reduction, yielded the satisfactory combination of strength and ductility. The yield strength and elongation were appropriate 767 MPa and 22.8%, respectively, which resulted from the optimized nanocrystalline/microcrystalline structure and distribution. [ABSTRACT FROM AUTHOR]

The effects of the rolling temperature on nanocrystalline phases and tensile properties of nanocrystalline/microcrystalline 316L stainless steel, that is, fabricated by the aluminothermic reaction method are investigated in this study. The rolling experiments are first performed at 1073 K with 40% and then with a 70% thickness reduction at the temperatures of 1073, 973, and 873 K. X‐Ray Diffraction (XRD) and SEM are used to analyze the evolution of the phases, and the microstructure is characterized using TEM. When the rolling temperature is 1073 K, the initial nano‐grains disappears gradually with the increasing rate of thickness reduction and are followed by the formation of the new sub‐micro grain phase. While the elongation increase to 24% monotonically, the strength of the steels initially increases and then decreases. When the rolling temperature decreases to 873 K, 316L stainless steels obtain a typical bimodal structure and achieve a super balance of high strength and considerable ductility (σ0.2 = 702 MPa, EL. = 20%). The nano‐grain fraction of approximately 50% is the optimized structure for bimodal grain size 316L stainless steel. [ABSTRACT FROM AUTHOR]