Dynamic viscosity of the lubricant and its effect on steel materials with boron

Abstract

In this work, the regularities of the change in the shear strength of the adhesive bond τ₀ and the piezoelectric coefficient β in the metal systems "12Kh2N4 (45KhN2MFA) - steel 45 + B", "12Kh2N4 (45KhN2MFA) - steel 45 + VS" were obtained during physical modeling of the shear of surfaces of small-sized samples and changes in dynamic viscosity environment of their interaction with the use of additional equipment of the SMTs-2 friction machine. It has been established that boriding and boron carburizing of the surface of steel 45 leads to the absence of adhesion to the surfaces of steels 12Kh2N4 and 45KhN2MFA in certain ranges of normal pressures, at which τ₀> 0 and the dynamic viscosity of liquid and grease. It was found that the parameter τ₀ when lubricating surfaces is determined to a greater extent for the system "12X2H4 - steel 45", and partially for borating steel 45 and low values of dynamic viscosity μ = 0.027 Pa•s. With an increase in the dynamic viscosity of the liquid phase of the lubricant in the "12X2H4 - steel 45" system, there is a tendency to an increase in the value of τ0. It was found that the absence of modification of steel 45 with boron and boron carbide predetermines the independence of the piezoelectric coefficient from the viscosity of the liquid lubricant and the shear rate. Вoriding and boron carburizing steel 45 predetermines an increase in the piezoelectric coefficient by an average of 1.6 times with an increase in dynamic viscosity from 0.027 Pa•s to 0.19 Pa•s at a shear rate of 10.16±0.8. At shear rate = 5.08±0.6 mm/s, the piezoelectric coefficient is relatively constant in the systems under study. With the transition to contact through a grease lubricant, there is an ambiguous manifestation of the rate of change of the piezoelectric coefficient.