The results of theoretical and experimental studies of the surface of the sample of steel 45 after surface plastic deformation (SPD) with multi-radius roller (MR-roller) is shown. The goal of this study is to expand the technological capabilities of the method of SPD through the use of a new design of the deforming tool developed at the Department of Engineering Technology of KuzSTU. The advantage of the MR-roller (Patent RU № 2557377) over the traditional tool for SPD (single-radius roller) is the possibility of creating a large hydrostatic pressure in the deformation zone, without destroying the surface layer of the processed material. The research technique included finite element modeling (FEM), microhardness measurement, metallographic studies of the sample structure. As a result of the study, some regularities of the process of hardening by a multi-radius tool with high hydrostatic pressure and a large number of quasi-monotonic deformation sites were revealed. The results indicate a significant hardening without metal destruction and the formation of nanoscale grains, which allows to improve the properties of rolled products in the application of high operating loads.

The results of experimental studies of the thin surface layer of samples made of steel 45 after treatment with surface plastic deformation (SPD) multiradius roller (MR-roller) are presented. On the basis of the apparatus of the mechanics of technological inheritance, taking into account the effect of the solidified body, a model of the process according to the scheme of multiple loading-unloading of metal, taking into account the phenomenology of the SPD process and the properties of the material, is created. Distributions of parameters of the stress-strain state in the deformation centre are obtained, the parameters of roughness and microhardness of the surface layer are investigated.

The study looks at features the formation of the structure of the surface layer of pure-iron after hardening treatment with surface plastic deformation (SPD) by a multiradius roller (MP-roller). Earlier authors with the help of the method of finite-element modelling (FEM) of the MP-roller SPD process proved the possibility of creating high hydrostatic pressure in the deformation center of the part being processed. The methods of optical (OM) and atomic-force microscopy (AFM) and X-ray structural analysis have determined that the MR-roller SPD results in the formation of an intensively deformed surface layer of the component with characteristic ferrite grains, stretched in the direction of the current of the metal and an average size of 20-30 μm. Analysis of the results of the X-ray structural analysis showed that the processing of the SPD by the MP-roller results in a significant increase in the microdistortion of the crystal lattice, which is characteristic of the nanodimensional structure. The data obtained are well consistent with the results of the finite element modelling previously obtained.

The structure of pure iron after surface plastic deformation (SPD) by a multiradius roller (MR-roller) was studied using optical microscopy (OM) and atomic force microscopy (AFM). An optical microscope of reflected light is used to study the size and uniformity of grains and subgrains (Neophot-21). The fine structure of the sample surface was studied using an atomic force microscope (Solver PH47-PRO) contact method. The paper shows changes in the deformation relief of the material after processing with an MR-roller.

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