Study on the Effects of Hydrostatic Pressure on the Structural State of Pure-Iron during Hardening Treatment with a Multiradius Roller

Abstract

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.