The dependence of performance characteristics of roller bearing on material used

The main materials for the manufacture of rolling stock bearing assemblies are steel ShKh15, ShKh15SG, ShKh4. The article discusses the possibility of using steels 20Kh2N4A, 95Kh18-Sh, 12Kh18N9T as alternative materials, an assessment of the arising contact stresses on the surfaces of the raceways of the bearing rings and rolling elements is given. When using 12Kh18N9T steel, the maximum contact stresses are reduced by 4 % in comparison with standard materials, which can provide an increase in the resource of the bearing assembly.

Influence of phase composition of austenitic-martensitic trip-steel VNS9-Sh on characteristics of dry sliding friction in tribocontact with steel ShKh 15

The influence of content of the martensite phase that is from 0 to 50% (vol.) on hardness and tribomechanical properties of trip-steel VNS9-Sh (ВНС9-Ш) under conditions of dry sliding friction on steel ShKh15 (ШХ15) (counterbody) has been investigated. It was found out that the best combination of hardness and wear resistance was possessed by steel with martensite phase content ≈32% (vol.). It is shown that with comparable hardness and tribomechanical properties, VNS9-Sh steel is more than twice as strong as 110G13L steel (110Г13Л).

Effects of structural inhomogeneities on the steel balls resistance to loading

When conducting impact tests of protective glasses, nonunique cases of destruction of balls made of bearing steel ShKh15 were recorded. The causes of their destruction were determined. The state of the material was studied by fractographic and metallographic analysis, hardness and microhardness measurement. In the structure of the metal of all the balls, no critical defects were found such as flockens, shells and microcracks, but adverse factors were detected in the microstructure of the material, namely, the presence of fineneedle martensite with excessive carbides. It is established that the detected structural factors lead to liability to brittle fracture, an increase in the hardness of the material, a decrease in plasticity. To prevent brittle fracture of the balls and provide a reserve of plasticity of steel ShKh15 at high shock loads assessment calculations of ductility coefficient were made; and it was recommended to limit the maximum hardness of the material critical value HV=5.70 HPa (54 HRC), with the corresponding plasticity coefficient equal to 0.8.

Использование метода акустоупругости для контроля упругих механических напряжений в материале колец подшипников

Designed and manufactured samples of the interference fit of the bearing rings on the neck of wheelset axle. The hydraulic stand for loading bearing rings has been certified. The stand simulates the pressing fit of rings on the axis. A mathematical model of the method for monitoring mechanical stresses of the bearing ring by the acoustoelastic method for chordal sounding has been created and solved. The model takes into account the change in the angle between the direction of wave propagation and the axis of the main mechanical stresses. Experimentally by loading the bearing rings are determined by the coefficient of customproperty longitudinal waves in steel SHKH15. The bearing ring tension was measured using the acoustoelasticity method on the bearing tension samples.

Semiempirical Mathematical Models of Spinning Friction Steel ShKh15 Steel Titles on Steel R6M5, on a Scheme of a Globe Plane Taking into Account Wear

The paper presents the results of the study of the friction of the spherical ball made of steel SHKH15 on the flat surface of the prism of steel R6M5. It has been established that as a result of the friction of the rotation according to the “ball-plane” scheme, at a steady wear mode, the torque of the friction of the rotation also becomes steady. It is shown that the change in the friction torque of the rotation from the load does not fit within the limits of one linear dependence, similar to G. Amonton's law. Semi-empirical models of friction rotation are given.

Influence of copper content on wear behavior of composites “steel ShKh15/copper” at sliding against copper under electric current of contact density higher than 100 A/cm2

Powder composites “steel ShKh15/copper” in alumina ceramics and graphite powders surrounding were sintered in the air. Powder steel was restored from grinding slime of bearings production. It is shown that the steel framework has low level of mechanical properties, but high pore space percolation. Copper concentration increases isolated pores concentration impeding oil impregnation. This effect did not allow making the long and steady sliding electric contact with contact current density higher than 150 A/cm2. The sintered composites based on recycled bearing steel and containing near 15%Cu show high wear resistance at sliding with a contact current density 150–200 A/cm2 under boundary lubrication.