Effects of Rolling Temperature on the Microstructure and Mechanical Properties in an Ultrafine‐Grained Low‐Carbon Steel. Issue 2 (4th September 2018)

• Record Type: Journal Article
• Authors: Yuan, Qing; Xu, Guang; Liu, Man; Hu, Haijiang; Tian, Junyu
• Is Part Of: Steel research international. Volume 90:Issue 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-04
• Subjects: cryorolling -- Fe3C -- microstructure -- property -- ultrafine grain; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.201800318
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : Ultrafine grained low‐carbon steels are fabricated by cryorolling and cold‐rolling martensite starting microstructure at liquid nitrogen temperature and ambient temperature, respectively. The results indicate that cryorolling process at liquid nitrogen temperature present more potential in refining ferrite grains in low‐carbon steel (132 nm) than ambient temperature deformation (330 nm). The tensile strength increase from 867.0 to 970.2 MPa for the specimen cryorolled at liquid nitrogen temperature compared to the specimen rolled at ambient temperature. The decreased elongation in the specimen at liquid nitrogen temperature is attributed to the coarse Fe3 C particles during the annealing. Moreover, Fe3 C particles precipitate during the cold‐rolling and subsequent annealing processes in the cold‐rolled specimen, while Fe3 C particles in the cryorolled specimen are mainly formed during the annealing process due to the suppression of diffusion of carbon atoms during the cryorolling process. Abstract : The schematic diagram of the formation of ultrafine grains in the low‐carbon steels is presented in Figure 1. Large amount of dislocation is induced in cryorolled specimens and martensite dimension sharply decreases. Finer ultrafine ferrite grains are formed and the spherical Fe3 C are coarsened in the cryorolled specimens. The decreased elongation is attributed to the coarse Fe3 C in the cryorolled specimens.