Maciej Michnej
Wpływ technologicznych metod podwyższenia trwałości warstwy wierzchniej na zużycie frettingowe osi kolejowych zestawów kołowych
W niniejszym artykule przedstawiono badania mające na celu zastosowanie takich technologii ulepszania warstwy wierzchniej podpiaścia zestawu kołowego, które eliminowałoby zużycie frettingowe. Badania zostały przeprowadzone na uproszczonym modelu fizycznym rzeczywistego połączenia koła i osi zestawu kołowego z samoczynną zmianą rozstawu kół. Wyniki przeprowadzonych badań zużyciowych wskazują, że obróbką skutecznie ograniczająca rozwój zużycia frettingowego może być zastosowanie powłoki metalicznej w postaci molibdenowania. Przeprowadzone badania wskazują na pełną możliwość zastosowania tego rozwiązania w rzeczywistej eksploatacji.
Influence of technological methods increasing surface layer durability on axles fretting wear in railway wheel sets
The article presents studies whose aim is to use such technologies of improving surface layer of a wheel seat that would eliminate fretting wear. The studies were carried out on a simplified physical model of an actual connection between the wheel and the axle of a wheel set with a self-acting wheel track change. The results of carried out wear studies show that fretting wear development can be successfully limited when metallic coating in the form of molybdenizing is used. Carried out studies indicate that such a solution can be fully used in actual exploitation.
Physical and reliability aspects of high-pressure ammonia water pipeline failures
The paper concerns the problem of the occurrence of failures of the high-pressure ammonia water pipeline of the coke oven battery complex, which is affected by chemical and thermal factors as well as the operating pressure occurring during its use. Pipeline failures manifested themselves as leaks (leakage of the medium) due to cracks in the area of the pipeline thermal elongation compensators. The conducted tests included, among others: visual inspection, penetration tests, macroscopic and microscopic tests as well as chemical analysis of the material. The study includes microscopic photographs of the material structure and cracks. The results of the pipeline strength and reliability analysis were also presented. On the basis of the conducted research and analyses conclusions were formulated. The assumed cause of the damage was the incorrectly made welded joints. Formulated recommendations and proposals for actions aimed at avoiding further failures of this and similar pipelines were related to the inspection time and preventive renewal.