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Measures to prevent damage and to extent the service life of a rotary excavator

Arsić Dušan, Nikolić Ružica R., Arsić Aleksandra, Cvetković Dragan, Pastorková Jana, Bokuvka Otakar

Production Engineering Archives

2025

Vol. 31, Iss. 1

73--80

The rotary excavator is a complex machine system, the main part of the ECS (excavator-conveyer-spreader) system, used in open-pit mining. Such a machine’s service life can last for decades, it gen-erally operates in the harsh exploitation conditions, which requires that its vital structures must be continuously controlled and well maintained. Damage or fracture of parts or assemblies of a rotary excavator can be caused by influence of various manufacturing, construction, exploitation conditions or environmental factors. Analysis of those eventual failures can be performed by various methods, out of which the most suitable are the failure analysis methods, for example the fault-tree analysis (FTA), the Ishikawa fishbone (cause-and-effect) diagrams or the failure modes and effects analysis (FMEA). In this article are presented results of the fault tree analysis of possible causes of rotary excavator’s parts, as well as measures to prevent their damages and/or fractures and to extend the service life of an excavator as a whole. The model of the organizational system for the rotary excava-tor’s maintenance is given, as well.

Reparation of a massive machine part made of grey cast iron

Arsić Dušan, Nikolić Ružica, Bokuvka Otakar, Zuziakova Ingrid, Arsić Aleksandra

System Safety : Human - Technical Facility - Environment

2024

Vol. 6, iss. 1

109--117

The analysis of the reparation procedure of the damaged turbine diaphragm from the ironworks plant, which was subjected to wear during the long-term exploitation process, is presented in this paper. The two-thirds of the bearing volume of the turbine diaphragm, made of grey cast iron EN-GJL-150, were damaged, and its functional properties were lost. The reparation was executed by the multi-layer hard-facing process. The procedure included verification of the material’s chemical composition, mechanical properties and metallographic structure, necessary for definition of the appropriate methodology for the part’s rehabilitation. The hard-facing was executed with preheating, as well as the post-welding heat treatment, with specifically selected filler materials and all the adequate welding process parameters. The executed hard-facing procedure turned out to be the cost efficient since, as a rule, the costs of reparation did not exceed 20 % of the price of that would be paid for acquiring the new part.