DOI: 10.18503/1995-2732-2022-20-2-82-90
Abstract
The paper describes studies on three proposed promising methods for local ion nitriding of steels of a wide class: 16Kh3NVFMB-Sh, 38KhMYuA, R6M5, 12Kh18N10T and 13Kh11N2V2MF-Sh, to create diffusion layers with different thickness and mechanical properties on the treated surface in one vacuum cycle. The first method is based on creating high-density plasma on sections of parts, using the effect of a hollow cathode. The second method proposes the creation of highly ionized glow discharge plasma, using crossed electric and magnetic fields on the local sections of parts. Increase in diffusion layer thickness in local areas during ion nitriding is attributed to an increase in the concentration gradient of a saturating element in the chamber formed by a hollow cathode or crossed electric and magnetic fields. The third method is implemented by refining a material structure by plastic deformation methods before the nitriding process on the areas of high-wear parts. As a result of such structure refinement, local areas of machine parts and mechanisms show intensified diffusion processes and formed wear-resistant hardened layers. The paper presents research on microstructures of steels after local ion nitriding with the proposed methods, and microhardness measurements of the hardened layer on the various treated areas. It has been found that during ion nitriding with a hollow cathode or in crossed electric and magnetic fields, using high-density glow discharge plasma, the local area of the part shows the formation of a diffusion layer, which is 2–2.5 times larger than during classical ion nitriding. Ion nitriding of parts with a preliminary refinement of the material structure with plastic deformation methods before the diffusion saturation process contributes to forming in individual sections of the part diffusion layers, which are ~ 2 times thicker than the relevant indicator, achieved during nitriding of parts with an unchanged structure. The methods under study will provide for processing heavy-loaded parts of machines and mechanisms, operating under local wear conditions.
Keywords
local ion nitriding, glow discharge, hollow cathode effect, crossed electric and magnetic fields, steel, structure, microhardness, hardened layer.
For citation
Khusainov Yu.G. Promising Methods for Local Ion Nitriding of Steels.Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2022, vol. 20, no. 2, pp. 82–90. https://doi.org/10.18503/1995-2732-2022-20-2-82-90
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