New technological methods of protecting the sur-faces of the parts of transport and lifting machines against fretting corrosion

Abstract

Damage to the surfaces of parts of transport and lifting machines from fretting wear is accompanied by the emergence of stress concentrators, changes in the mechanical properties of structural elements, weakening of tension and other phenomena, which leads to the destruction of individual structural elements and can cause serious accidents. Thus, the study of the problems of fretting wear, the study of the causes of its occurrence and the development of methods to increase fretting resistance is an urgent task that requires timely solution. Goal. The purpose of the work is to increase the reliability and durability of parts of transport and lifting machines by increasing the fretting resistance of joints by forming special coatings on the contact surfaces of the connecting parts. Methodology. Both analytical methods of research and experimental check of efficiency of the offered methods of increasing resistance against fretting wear of parts’ surfaces were used. Results. A study of the influence of various factors on the intensity and features of fretting processes on the contact surfaces of various parts of transport and lifting machines, substantiated the use of methods of electric spark alloying, epilation, metal plating of surfaces subjected to fretting wear. Originality. A new method of manufacturing a fixed joint type "Shaft - hub" of steel parts is offered, which provides the increased fatigue strength of the shafts in fixed joints and recommendations are developed for the materials used and processing modes. A new method of protecting the parts of the elastic coupling from fretting corrosion is proposed, in which a chemical and physical effect is performed on the surface layer of the parts in contact with friction pairs. A new method is offered for protecting flexible elements of elastic couplings from fretting corrosion and increasing their durability in more severe operating conditions, by changing the quality parameters of their surface layers by applying corrosion-resistant lubricants. Practical value. The use of the proposed technological methods provides a significant increase in resistance to fretting wear of the parts’ surfaces, which is confirmed by the results of the bench tests.