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New Antifriction Composites for Printing Machines Based on Tool Steel Grinding Waste. SUSTAINABILITY 2022. [DOI: 10.3390/su14052799] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
In this article, we present research results on the structure and properties of new self-lubricating antifriction composites based on 4H4VMFS tool steel grinding waste with solid lubricant additives. The new composites are designed to work in the friction units of offset cylinders in printing machines at rotation speeds up to 7000 rpm and increased loads up to 5.0 MPa. The developed technology formed composites with a fine-grained heterophase structure with a metal matrix base of tool steel 4H4VMFS regenerated grinding waste, consisting of high-alloy α−solid solution and hard grains of alloying element carbides, as well as evenly distributed CaF2 antiseizure solid lubricant. This structure ensured the formation of composites with favorable functional properties. During the friction process, antiseizure films were formed on the contact surfaces, resulting in a self-lubrication mode. Comparative tests for friction and wear showed significant advantages of the new waste composite compared to cast bronze parts, which are traditionally used in the friction units of offset cylinders of rolled newspaper printing machines. The stable operation of the new composite made it possible to ensure a “wear-free” effect. Studies have shown the importance and prospects of using the wide range of valuable grinding waste in the reproduction cycle to manufacture quality composites. Reuse of such waste would significantly protect the environment from pollution connected with human activity industrial and mitigate negative impacts on ecosystems and the biosphere.
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Friction Mechanism Features of the Nickel-Based Composite Antifriction Materials at High Temperatures. COATINGS 2020. [DOI: 10.3390/coatings10050454] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The friction behavior of the formed antifriction films and their effect on the functional properties of the composite based on the powder nickel alloy EI929 with solid lubricant CaF2 at high temperatures was investigated. An antifriction film was formed on the contact surfaces during the friction process. Such a film was the result of the interaction of the contact surfaces with atmospheric oxygen at high temperatures. It contains oxides of alloying elements from materials of the frictional contact and solid lubricant calcium fluoride. The quantitative ratio of formed oxides depends on the temperature operating conditions of material. The data of thermodynamic simulation of the high-temperature interaction of the composite with oxygen coincide with the experimental data obtained by studying the fine structure of surface antifriction films. Antifriction films consist of oxide phases in combination with solid CaF2 lubricant. Anti-friction films provide high wear resistance of the self-lubricating composite in the range of temperatures 1073–1173 K due to the balance between the rate of their formation and wear. When the temperature exceeds 1200 K, the film loses its lubricating properties and acts as an abrasive substance due to the intense oxidation. Abrasive surfaces of materials were subjected also to microscopic examination, in which the mechanically mixed layer (MML) was described. The study of the friction surface roughness parameters confirmed the presence of the formed friction self-lubricating film and allowed to determine its parameters. The friction mechanism was the formation of an oxide layer combined with a solid lubricant, which provides high antifriction properties in the range of 1073–1273 K.
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Abstract
Calcium Fluoride (CaF2) was selected owing to its cubic symmetry and excellent luminescence properties as a crystal of interest, and ultrafast laser inscription of in-bulk double-track waveguides was realized. The guiding properties of these waveguides in relation to the writing energy of the femtosecond pulse are presented. The modified double-track waveguides have been studied by systematic developments of beam propagation experiments and numerical simulations. Furthermore, an adapted model and concepts were engaged for the quantitative and qualitative characterization of the waveguides, particularly for the transmission loss measurements and the three-dimensional refractive index mappings of the modified zones. Additionally, polarization-dependent guiding was investigated.
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