ANALYTICAL ASSESSMENT OF WEAR OF THE WORKING SURFACE OF SCREW DEVICES WITH COMPOSITE COATING

Abstract

Equipment for the production and transportation of bulk agricultural materials operates under extremely difficult operating conditions, is exposed to abrasive particles of the processed material. Such working conditions lead to changes in operational properties, deterioration of the technical condition of the equipment and the occurrence of malfunctions, which are expressed in changes in the original shapes, sizes, weight, structure of the material and mechanical properties. (Research purpose) The research purpose is to predict the performance of composite coatings using a mathematical apparatus that adequately describes the process of abrasive wear of the contact surface of the grain conveyor auger when working with abrasive particles of the processed material. (Materials and methods) As a sample for modeling the process of surface wear, authors chose a screw conveyor, the working screw surface of which is treated with plasma spraying in order to increase its wear resistance. The screw works in an abrasive environment, without touching by the contact surface with other bodies. External abrasive wear is characterized by the presence of scratches or cavities oriented in the direction of sliding. The article presents the model of abrasive wear of the grain conveyor screw and numerical methods of its calculation. (Results and discussion) The article describes a method for assessing the wear resistance of restored shafts by determining the wear intensity of the surface of the part and the energy intensity of linear wear for parts with non-stationary geometry. The article presents a method for calculating the shape and contact area of composite particles with the recovered surface. The obtained expression is valid when ensuring the deviation of the screw speed during the test from the nominal one, not exceeding 10 percent of the set value, the error of applying the load on the screw does not exceed 5 percent. (Conclusions) As a result of the study, the article presents the dependence of the intensity of abrasive wear as a function of the geometry of the surface to be restored and the density of the applied material.