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Abstract:
In the article, a direct choice system of the most rational technology for applying a babbitt coating on the liners of sliding bearings (SB) is developed, which takes into account both economic and environmental requirements. On the basis of the performed research, a physically substantiated mathematical model of the babbitt-coatings’ wear process (wear equation) is proposed, which allows solving both the direct problem of determining weight and linear wears based on the known work of friction, as well as the inverse problem of finding the necessary work of friction to obtain the required amount of weight or linear wears. With knowing the time to reach a certain amount of wear, it becomes possible to operate the products more rationally, timely assigning the repair time and friction-surface catastrophic-wear preventing. In the course of research, a methodology is developed for determining the constants of the wear equation: activation energy (EA) as well as maximum weight (Δmб.п.н) and linear (Δhб.п.н) wears, which can be used as selection criteria for the most rational technology of applying a babbitt coating.

Keywords:
sliding bearing, babbitt, coating, wear, structure, transition layer, adhesion strength, electrospark alloying, mathematical model

Abstract:
The article substantiates the importance and relevance of increasing problem of the performance and service life of babbitt sliding bearings (SB), which are the rotors supports of a large number of centrifugal pumps, compressors, turbines and other dynamic equipment operating at high operating parameters (speeds, loads and temperatures), as well as in conditions of corrosive, abrasive and other types of working environment’s influence. The analysis of the babbitt SBs production technology and operating conditions showed that the reason for the decrease in their durability are factors that are formed both at the stage of manufacture and during operation. SB failure under normal operating conditions is a consequence of wear various types: cavitation, abrasive wear, damage due to plastic deformations, fatigue damage, etc. The antifriction layer wear resistance depends on the mode of operation and design of the bearing, the physical properties of the connection between the layer and the base, the rigidity of the shaft and the bed under the bearings. As established, the bearing anti-friction layer quality must be evaluated according to the following criteria: adhesion strength of the coating to the base, cohesive strength of the anti-friction layer, porosity, and homogeneity of the structure. As established, during the production of SBs, the formation by the method of electrospark alloying (ESA) of a copper intermediate layer, firmly bonded with steel substrate, and tin layer (formation of solid substitution solutions) and babbitt provides a stronger (by 35%) of adhesion, compared to traditional technology (steel 20 + babbitt), steel substrate with babbitt, as well as more intensive removal of heat from the friction zone. As determined, a new technology in which all operations are carried out by the ESA method can be a reserve for improving the babbitt coatings formation quality, which significantly affects the durability of the SB. As determined, in order to determine a more rational technology for applying babbitt coatings, it is necessary to develop a physically based mathematical model that relates the wear of a certain amount of babbitt to the frictional work spent on it.

Keywords:
sliding bearing, babbitt, coating, wear, structure, transition layer, adhesion strength, electrospark alloying, mathematical model