DOI: 10.18503/1995-2732-2024-22-4-120-133
Abstract
Problem Statement (Relevance). The prospects for the use of a unique metal with a shape memory effect in the design of machinery are hampered by the problems of its mechanical processing. This research is designed to improve the machinability of nitinol. Objectives. It is required to prove the possibility of the martensite-austenite phase transformation of nitinol on the surface using technological methods, which allows achieving precision in abrasive processing of planes. Methods Applied. The work is an experimental study using mathematical statistics. Originality. It has been determined that nitinol, unlike other metals, has low cutting machinability when removing large volumes of materials with high process productivity. Result. For the first time, the possibility of controlling phase transformations in nitinol by grinding mode parameters has been confirmed. Based on ANOVA and regression analyses, stochastic models were obtained and microhardness response surfaces were studied, as one of the main characteristics of the phase composition of the metal, taking into account the influence of grinding modes and characteristics of the abrasive tool. Changes in surface accuracy were obtained when grinding the surface with preliminary thermal hardening by plasma and quenching in water, and without it. Ultimately, the machinability of nitinol with an operating temperature above +75ºC is ensured due to changes in microhardness in the surface layer of parts because of phase transformations. Practical Relevance. Equations are proposed to describe the surface quality indicator, the magnitude and pattern of changes in the error of the shape of the planes, as well as recommendations for abrasive wheels, in particular regarding grain size and porosity. Grinding modes with abundant cooling and plasma thermal hardening parameters have been developed to ensure a guaranteed deviation from flatness of up to 7 microns. A technological process route for processing nitinol parts has been proposed.
Keywords
shape accuracy, microhardness, grinding, plasma heat treatment, titanium nickelide, phase transformations
For citation
Kazimirov D.Yu., Soler Y.I. Achive Surface Precision When Grinding Nitinol With High Transformation Temperatures. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2024, vol. 22, no. 4, pp. 120-133. https://doi.org/10.18503/1995-2732-2024-22-4-120-133
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