The Paton Welding Journal, 2022, №06



2022 №06 (02)

DOI of Article 10.37434/tpwj2022.06.03

2022 №06 (04)

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The Paton Welding Journal, 2022, #6, 17-21 pages

Repair of the body of connecting rod of mobile jaw crusher Metso Lokotrack LT 120

V.D. Poznyakov, O.A. Gaivoronskyi, Yu.V. Demchenko, A.M. Denysenko, G.V. Zhuk

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

Abstract
The paper describes the experience of repair welding of service defects in the body of the connecting rod of mobile jaw crusher Metso lokotrack LT 120, which is a rather rigid honeycomb structure from cast low-alloyed steel of 20GL type with thickness of external walls of 60 mm and of partitions of not less than 45 mm and more than 5 t weight. It was found that the most significant defects — fatigue cracks and cleavage which are incompatible with performance, naturally formed near the structural stress raisers, service damage, caused by contact impact of armour protection, casting defects, as well as in the sites of unsmooth connection of elements, etc. Crack opening displacement is equal to 2‒3 mm that is indicative of the start of shape change of the body and need for prevention of further operation in such a state. Rigid structure of the connecting rod body and general state of destruction required special technology of repair welding, which was created and realized by the authors. It included new welding consumables, technological measures and engineering solutions and those verified by our own practical experience of repair of cast structures, as well as high skill and competence of the welders. Practical importance and effectiveness of the performed work on connecting rod repair was confirmed by safe operation of the crusher in the design mode for two years.
Keywords: connecting rod, service defects, design stress raisers, through-thickness cracks, repair-welding technology, rigid framework, weldability, mechanical peening of welds

Received: 18.05.2022
Accepted: 15.08.2022

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