Rotating Roll Induced By Low-carbon Steel Surface Nanocrystallization

By mean of circulation rolling plastic deformation (CRPD), a nanostructured surface layer was formed on a 10# steel. The microstructure features were systematically characterized by using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. Microhardness on the surface layer were measured by microhardness testing machine. The results show that the nanostructured surface layers were obtained on a 10# steel with bcc structure, the grain size on the nanocrystalline surface was about 20 nm, the depth of deformed layer was 800 urn, the surface microhardness was 600 HV, which was 3times of that of the initial sample.The low temperature annealing behavior of the sample after the CRPD treatment was investigated. It was found that variation of annealing temperature affluences the distribution of hardness on the surface layer. The microhardness first increases, which reaches highest values at 573K ( increases 8% than the initial sample), then deceases with annealing temperature increasing.Ion implantation behavior of the sample after CRPD treatment was investigated in comparison with that in the origin sample. It was found that the nitrogen content on the surface layer of the sample subjected to CRPD treatment is higher than that in origin sample with the same ionimplanting treatment parameter. After ion implantation, implanting depth of the CRPD sample was about 600 nm, while which of the origin sample was a few nm, mainly due to fast atomic diffusion channels of grain boundaries of nanoscale microstructure introduced by circulation rolling plastic deformation.