L. I. Kuksenova

Criteria for efficiency and choice of materials for sliding supports accounting for lubricant properties

The authors discuss the criteria for sliding support efficiency and the influence of the structure of structural and lubricating materials on corresponding parameters. The application of active lubricants proved to be able to increase the load capacity as one of the parameters of efficiency.

Effect of composition and structure of nitrided iron alloys on wear resistance under friction and sliding

Characteristic features of the formation of the wear-resistant structure of the nitrided model alloys with body-centered cubic (bcc) and face-centered cubic (fcc) lattices are studied, including Fe-Mo, Fe-Cr, Fe-Al, Fe-Ni-Cr, Fe-Ni-Al, Fe-Ni-Ti, and Fe-Ni-Cr-Al-Ti. Interrelations are established between the parameters of the structure of the nitrided layer and the wear resistance of alloys. It is shown that, in alloys with the bcc lattice, maximum wear resistance is achieved by the formation of incoherent particles of nitrides of alloying elements, and the maximum hardness can be found in the alloy with coherent nitrides. In alloys with the fcc lattice, maximum hardening during nitriding and wear resistance are achieved at the stage preceding the rupture of coherent communication of the nitride with the lattice. Interconnections of characteristics of the structure of the nitrided layer and the wear resistance are discussed in the context of the formation of the wear-resistant structural state of alloys.

Application of the microplasma method for strengthening of the near-surface layer of samples made from steel 45

Strong local interaction of microplasma discharges with samples made from construction steel 45 is investigated experimentally. It is found that a remelted region with strongly changed physicochemical properties of the material is formed in the near-surface layer of samples treated with microplasma discharges. It is shown that roughness, microhardness, wear resistance, and other properties of treated samples made from steel 45 differ considerably from the corresponding starting values.

The Influence of High-Pressure Gas Nitriding on the Properties of Martensitic Steels

The influence of high-pressure gas nitriding on the structure and properties of martensitic steels VKS-5, VKS-7, 20Kh3N3MFB, and 25Kh5M is investigated. It is shown that the high-pressure nitriding increases the thickness of the diffusion zone at substantial reduction of the process time as compared to the traditional gas-phase nitriding. Increase of the post-treatment cooling rate above 30 K/min favors the formation of diffusion layers with greater hardness.

Methods for estimating the adaptive properties of mechanical systems as means of improving their performance indicators

The article proposes criteria and methods for estimating the adaptive properties of mechanical systems, such as sliding bearings, worm gears, and internal combustion engines. The examples of estimating the adaptation effects under the conditions of using the film-forming lubricants have been given.

Mixed-surface impregnation of gear wheels made of 13Kh3N3M2VFB-Sh age-hardenable integrally alloyed steel aimed at improving surface hardness, wear-resistance, and back-to-back endurance

An analysis has been carried out of mixed-surface impregnation of the 13Kh3N3M2VFB-Sh age-hardenable integrally alloyed steel consisting of successive vacuum carburizing, heat treatment, grinding and nitriding in the glow-discharge was made. Test results of samples hardened by mixed-surface impregnation for back-to-back endurance and wear resistance have been presented. It has been shown that mixed-surface impregnation combines the advantages of vacuum carburizing and nitriding. A surface hardness of more than 1000 HV has been achieved via the mixed-surface impregnation of this stated steel.

Assessment of critical level of shear stresses in tribocouples of Аl2O3 and metal details of ITER blanket modules

The shear strength of plasma-sprayed electroinsulating Аl2O3 coating has been determined for blanket modules of a thermonuclear reactor in a friction couple with 316L(N)-IG steel and BrAZhNMts9-4-4-1 bronze. An analysis of the experimental and calculated data on the influence of shear stresses on the electric insulation of blanket modules has revealed the need to decrease the coefficient of friction to permissible level [f] = 0.28 in the range of contact pressures Р = 3–500 MPa.

Development of method for evaluating performance of worm gears via analysis of their tribological characteristics

The occurrence of self-excited frictional oscillations in a worm gear and their interrelation with the performance characteristics of the gear are considered. A method for accelerated testing of worm gears is proposed based on the obtained relations. Results of the tests carried out using various lubricants are presented.

Analysis of microplastic deformation processes of surface layers of nitrided structural steels

A model of microplastic deformation in surface layers of nitrided structural steels under the incoherent boundaries of nanodisperse reinforcing particles formed upon thermochemical treatment is considered, allowing the adaptive evolution of deformation without the accumulation of defects at the near-boundary zones, which provides high wear resistance of the material.

Mechanical Properties of Surface Layers of Structural Steels After Nitriding and Possibilities of Adaptation of Their Nanostructure to Contact Deformation

The mechanism of plasticity of surface layers of structural steels after nitriding that yields nanosize particles with incoherent boundaries is considered with allowance for the possibility of adaptation diffusion processes initiated by friction strain.