International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Rolling element bearing fault detection is of significant importance due to the widespread use of bearings across numerous industrial applications. In this study, vibration measurements using an accelerometer and a laser displacement sensor are carried out on a laboratory bearing test rig under different operating conditions, including a healthy state and bearings with localized inner- and outer-ring faults. Measurements are conducted at a constant rotational speed of 1700 rpm and the acquired signals are analysed to extract characteristic features associated with potential bearing faults. The results demonstrate that the applied methodology enables indicative bearing fault detection using both measurement approaches.

The intensification methods for carburizing and nitrocarburizing investigated in this study include the use of biochar, preliminary oxidation, and plastic deformation. The possibility of combining oxidation and plastic deformation was also examined.

The evolution of phase composition and mechanical properties and the formation of oxide layers on Fe40–xNiCoCrAlx (x = 5 and 10 at.%) alloys in long-term oxidation at 900 and 1000 °C were studied. In the initial cast state, depending on the aluminum content and valence electron concentration, the alloys contain only an fcc solid solution (VEC = 8 e/a) or a mixture of fcc and bcc phases (VEC = 7.75 e/a). Thin continuous oxide scales containing Cr2O3 and NiCr2O4 spinel formed on the surface of both alloys oxidized at 900°C for 50 h. A further increase in the annealing time to 100 h leads to the formation of aluminum oxide Al2O3 in the scale on the Fe30Ni25Co15Cr20Al10 alloy, having high protective properties. An increase in the oxidation temperature to 1000°C results in partial failure of the protective layer on the
alloy with 10 at.% Al. Long-term holding at 900°C (100 h) + 1000°C (50 h) does not change the phase composition of the Fe35Ni25Co15Cr20Al5 alloy matrix, being indicative of its high thermal stability. In the two-phase Fe30Ni25Co15Cr20Al10 alloy, the quantitative ratio of solid solutions sharply changes: the amount of the bcc phase increases from 4 to 54 wt.% and its B2-type ordering is observed. The mechanical characteristics of the starting alloys and those after long-term high-temperature annealing were determined by automated indentation. It is shown how the hardness (HIT) and the elastic modulus (E) of alloys change after oxidation, depending on the Al content.

In this paper behavior of inorganic compound (2-amino-5-ethyl-1,3,4-thiadiazole) as inhibitor of copper corrosion in acidic medium (HCl solution) was examined. In addition to examination the effects of different concentrations of the inhibitor on the corrosion processes, research also included investigation of influence of immersion time of copper electrode in 2-amino-5-ethyl-1,3,4-thiadiazole (AETDA) solution on protective film formation on electrode surface (copper electrode). During this study next experimental methods are used: open circuit potential measurements (OCP), linear voltammetry measurements (LV) and cyclic voltammetry measurements (CV). Shift of open circuit potential toward negative values indicate that on copper surface comes to formation of corrosion product sand adsorption of molecule inhibitor. Copper oxidation is consequence of existing defect in structure layer and layer dissolution on electrode surface. Results show that inhibition efficiency depend on inorganic inhibitor concentration and immersion time of copper electrode in inhibitor solution (azole derivatives solution). Inhibition mechanism of AETDA is explained by forming compact protective film on copper surface. Adsorption of 2-amino-5-ethyl-1,3,4-thiadiazole on copper surface in 0.05M HCl solution obeys the Langmuir adsorption isotherm. The value of adsorption energy amount: ΔG = -39,52 kJ/mol.